Cern News

ATLAS sets record precision on Higgs boson’s mass

In the 11 years since its discovery at the Large Hadron Collider (LHC), the Higgs boson has become a central avenue for shedding light on the fundamental structure of the Universe. Precise measurements of the properties of this special particle are among the most powerful tools physicists have to test the Standard Model, currently the theory that best describes the world of particles and their interactions. At the Lepton Photon Conference this week, the ATLAS collaboration reported how it has measured the mass of the Higgs boson more precisely than ever before.

The mass of the Higgs boson is not predicted by the Standard Model and must therefore be determined by experimental measurement. Its value governs the strengths of the interactions of the Higgs boson with the other elementary particles as well as with itself. A precise knowledge of this fundamental parameter is key to accurate theoretical calculations which, in turn, allow physicists to confront their measurements of the Higgs boson’s properties with predictions from the Standard Model. Deviations from these predictions would signal the presence of new or unaccounted-for phenomena. The Higgs boson’s mass is also a crucial parameter driving the evolution and the stability of the Universe’s vacuum.

The ATLAS and CMS collaborations have been making ever more precise measurements of the Higgs boson’s mass since the particle’s discovery. The new ATLAS measurement combines two results: a new Higgs boson mass measurement based on an analysis of the particle’s decay into two high-energy photons (the “diphoton channel”) and an earlier mass measurement based on a study of its decay into four leptons (the “four-lepton channel”).

The new measurement in the diphoton channel, which combines analyses of the full ATLAS data sets from Runs 1 and 2 of the LHC, resulted in a mass of 125.22 billion electronvolts (GeV) with an uncertainty of only 0.14 GeV. With a precision of 0.11%, this diphoton-channel result is the most precise measurement to date of the Higgs boson’s mass from a single decay channel.

Compared to the previous ATLAS measurement in this channel, the new result benefits both from the full ATLAS Run 2 data set, which reduced the statistical uncertainty by a factor of two, and from dramatic improvements to the calibration of photon energy measurements, which decreased the systematic uncertainty by almost a factor of four to 0.09 GeV.

“The advanced and rigorous calibration techniques used in this analysis were critical for pushing the precision to such an unprecedented level,” says Stefano Manzoni, convener of the ATLAS electron-photon calibration subgroup. “Their development took several years and required a deep understanding of the ATLAS detector. They will also greatly benefit future analyses.”

When the ATLAS researchers combined this new mass measurement in the diphoton channel with the earlier mass measurement in the four-lepton channel, they obtained a Higgs boson mass of 125.11 GeV with an uncertainty of 0.11 GeV. With a precision of 0.09%, this is the most precise measurement yet of this fundamental parameter.

“This very precise measurement is the result of the relentless investment of the ATLAS collaboration in improving the understanding of our data,” says ATLAS spokesperson Andreas Hoecker. "Powerful reconstruction algorithms paired with precise calibrations are the determining ingredients of precision measurements. The new measurement of the Higgs boson’s mass adds to the increasingly detailed mapping of this critical new sector of particle physics."

Find out more on the ATLAS website.

angerard Fri, 07/21/2023 - 15:38 Publication Date Fri, 07/21/2023 - 16:00

ATLAS sets record precision on Higgs boson’s mass

In the 11 years since its discovery at the Large Hadron Collider (LHC), the Higgs boson has become a central avenue for shedding light on the fundamental structure of the Universe. Precise measurements of the properties of this special particle are among the most powerful tools physicists have to test the Standard Model, currently the theory that best describes the world of particles and their interactions. At the Lepton Photon Conference this week, the ATLAS collaboration reported how it has measured the mass of the Higgs boson more precisely than ever before.

The mass of the Higgs boson is not predicted by the Standard Model and must therefore be determined by experimental measurement. Its value governs the strengths of the interactions of the Higgs boson with the other elementary particles as well as with itself. A precise knowledge of this fundamental parameter is key to accurate theoretical calculations which, in turn, allow physicists to confront their measurements of the Higgs boson’s properties with predictions from the Standard Model. Deviations from these predictions would signal the presence of new or unaccounted-for phenomena. The Higgs boson’s mass is also a crucial parameter driving the evolution and the stability of the Universe’s vacuum.

The ATLAS and CMS collaborations have been making ever more precise measurements of the Higgs boson’s mass since the particle’s discovery. The new ATLAS measurement combines two results: a new Higgs boson mass measurement based on an analysis of the particle’s decay into two high-energy photons (the “diphoton channel”) and an earlier mass measurement based on a study of its decay into four leptons (the “four-lepton channel”).

The new measurement in the diphoton channel, which combines analyses of the full ATLAS data sets from Runs 1 and 2 of the LHC, resulted in a mass of 125.22 billion electronvolts (GeV) with an uncertainty of only 0.14 GeV. With a precision of 0.11%, this diphoton-channel result is the most precise measurement to date of the Higgs boson’s mass from a single decay channel.

Compared to the previous ATLAS measurement in this channel, the new result benefits both from the full ATLAS Run 2 data set, which reduced the statistical uncertainty by a factor of two, and from dramatic improvements to the calibration of photon energy measurements, which decreased the systematic uncertainty by almost a factor of four to 0.09 GeV.

“The advanced and rigorous calibration techniques used in this analysis were critical for pushing the precision to such an unprecedented level,” says Stefano Manzoni, convener of the ATLAS electron-photon calibration subgroup. “Their development took several years and required a deep understanding of the ATLAS detector. They will also greatly benefit future analyses.”

When the ATLAS researchers combined this new mass measurement in the diphoton channel with the earlier mass measurement in the four-lepton channel, they obtained a Higgs boson mass of 125.11 GeV with an uncertainty of 0.11 GeV. With a precision of 0.09%, this is the most precise measurement yet of this fundamental parameter.

“This very precise measurement is the result of the relentless investment of the ATLAS collaboration in improving the understanding of our data,” says ATLAS spokesperson Andreas Hoecker. "Powerful reconstruction algorithms paired with precise calibrations are the determining ingredients of precision measurements. The new measurement of the Higgs boson’s mass adds to the increasingly detailed mapping of this critical new sector of particle physics."

Find out more on the ATLAS website.

angerard Fri, 07/21/2023 - 15:38 Publication Date Fri, 07/21/2023 - 16:00

An even closer look at magic tin

In a new paper published in Physical Review Letters, researchers working at CERN’s ISOLDE facility describe how an upgrade to the ISOLTRAP experiment has allowed them to determine the energy necessary to bring the atomic nucleus of indium-99 from its ground state to a long-lived excited state called an isomer. The result follows an earlier ISOLTRAP measurement of indium-99 in the ground state, offering an even closer look at the nucleus of tin-100 – a “doubly magic” nucleus that is a mere proton above indium-99.

Atomic nuclei in which the constituent protons and neutrons each completely fill the orbital shells to capacity are more strongly bound than their nuclear neighbours. Such “doubly magic” nuclei provide stringent tests of theoretical models of the nucleus. This is the case of the tin-100 nucleus, which has 50 protons and 50 neutrons. But this special doubly magic nucleus – it is also the heaviest such nucleus comprising protons and neutrons in equal number – is particularly challenging to produce in the lab and is relatively short-lived. Researchers therefore turn to its more easily produced nuclear neighbours to try and reveal its secrets.

In their latest study, the ISOLTRAP team turned to indium-99, in particular to its isomer, which has a slightly different orbital occupation – and hence higher energy – than the ground state and results in a slightly larger nuclear mass. Using an upgraded version of the experiment’s multireflection time-of-flight mass spectrometer, the researchers were able to measure the difference in the time-of-flight of confined indium-99 nuclei in their ground and isomeric states. This small difference, which is caused by the different mass of the nucleus in these two states, made it possible to determine the energy necessary to excite the isomer.

The team then compared the result with measurements of isomer excitation energies for other indium neighbours, including a new ISOLTRAP measurement of indium-101. This comparison showed that the excitation energies are essentially the same down to the magic neutron number 50. The result is in stark contrast with recent results on the magnetic moments of indium nuclei from ISOLDE’s CRIS experiment, which saw their remarkably constant value undergoing a surprisingly abrupt change at magic neutron number 82.

The researchers also compared the results with several sophisticated types of theoretical calculations, including “ab initio” calculations that attempt to describe nuclei from first principles. They found that all of the calculations struggle to predict the isomer excitation energies and the magnetic moments simultaneously.

The results will guide researchers in their effort to develop a fully ab initio description of the nucleus, which continues to make promising progress.

abelchio Thu, 07/20/2023 - 13:32 Publication Date Thu, 07/20/2023 - 13:30

An even closer look at magic tin

In a new paper published in Physical Review Letters, researchers working at CERN’s ISOLDE facility describe how an upgrade to the ISOLTRAP experiment has allowed them to determine the energy necessary to bring the atomic nucleus of indium-99 from its ground state to a long-lived excited state called an isomer. The result follows an earlier ISOLTRAP measurement of indium-99 in the ground state, offering an even closer look at the nucleus of tin-100 – a “doubly magic” nucleus that is a mere proton above indium-99.

Atomic nuclei in which the constituent protons and neutrons each completely fill the orbital shells to capacity are more strongly bound than their nuclear neighbours. Such “doubly magic” nuclei provide stringent tests of theoretical models of the nucleus. This is the case of the tin-100 nucleus, which has 50 protons and 50 neutrons. But this special doubly magic nucleus – it is also the heaviest such nucleus comprising protons and neutrons in equal number – is particularly challenging to produce in the lab and is relatively short-lived. Researchers therefore turn to its more easily produced nuclear neighbours to try and reveal its secrets.

In their latest study, the ISOLTRAP team turned to indium-99, in particular to its isomer, which has a slightly different orbital occupation – and hence higher energy – than the ground state and results in a slightly larger nuclear mass. Using an upgraded version of the experiment’s multireflection time-of-flight mass spectrometer, the researchers were able to measure the difference in the time-of-flight of confined indium-99 nuclei in their ground and isomeric states. This small difference, which is caused by the different mass of the nucleus in these two states, made it possible to determine the energy necessary to excite the isomer.

The team then compared the result with measurements of isomer excitation energies for other indium neighbours, including a new ISOLTRAP measurement of indium-101. This comparison showed that the excitation energies are essentially the same down to the magic neutron number 50. The result is in stark contrast with recent results on the magnetic moments of indium nuclei from ISOLDE’s CRIS experiment, which saw their remarkably constant value undergoing a surprisingly abrupt change at magic neutron number 82.

The researchers also compared the results with several sophisticated types of theoretical calculations, including “ab initio” calculations that attempt to describe nuclei from first principles. They found that all of the calculations struggle to predict the isomer excitation energies and the magnetic moments simultaneously.

The results will guide researchers in their effort to develop a fully ab initio description of the nucleus, which continues to make promising progress.

abelchio Thu, 07/20/2023 - 13:32 Publication Date Thu, 07/20/2023 - 13:30

Accelerator Report: A quench of an LHC inner triplet magnet causes a small leak with major consequences

At 1.00 a.m. + 17 seconds on Monday, 17 July, the LHC beams were dumped after only 9 minutes in collision due to a radiofrequency interlock caused by an electrical perturbation. Approximately 300 milliseconds after the beams were cleanly dumped, several superconducting magnets around the LHC quenched – i.e. they lost their superconducting state. Among these magnets were the inner triplet magnets located to the left of Point 8 (LHCb), which play a crucial role in focusing the beams for the LHCb experiment.

While this sequence of events may not happen very often during beam operation, it is not exceptional for the LHC, as occasional quenches of some superconducting magnets are to be expected.

In this particular case, the electrical perturbation caused the quench protection system (QPS) to trigger the quench heaters of the magnets concerned. These quench heaters consist of an electrical resistor embedded in the magnet coils; they are designed to heat up quickly when a localised quench occurs somewhere in the magnet, in order to effectively bring the whole magnet out of the superconducting state in a controlled and homogenous manner. During such a quench, the liquid helium in the magnet warms up and turns into a gas that is recovered by the cryogenic system to be re-liquified, ready to cool down the magnets again.

The cryostat containing the inner triplet magnets. The tiny amount of very cold helium that replaced the insulation vacuum cooled down the cryostat, causing condensation of the tunnel air on the cryostat, which then froze. Several hours later, the thin layer of ice had melted again as the cryostat returned to room temperature. (Image: CERN)

Despite this being a normal and expected behaviour, the mechanical stresses involved in this process are significant and, in very rare cases, can lead to damage. Unfortunately, in the case of the inner triplet magnet located to the left of Point 8, a small leak has appeared between the cryogenic circuit, which contains the liquid helium, and the insulation vacuum that separates the cold magnet from the warm outer vessel, known as the cryostat. This vacuum barrier is crucial for preventing heat transfer from the surrounding LHC tunnel to the interior of the cryostat (this is similar to the functioning of a thermos flask). As a result of the leak, this insulation was lost: the insulation vacuum filled with helium gas, cooling down the cryostat and causing condensation to form and freeze on the outside.

As I write, investigations are ongoing to identify the source of the leak, to allow a repair strategy to be elaborated. Nevertheless, it is clear that an intervention with the inner triplet magnet at room temperature will be required. This incident will probably have a great impact on the LHC schedule, with machine operation unlikely to resume for at least several weeks.

anschaef Thu, 07/20/2023 - 12:32 Byline Rende Steerenberg Publication Date Wed, 07/19/2023 - 12:31

Accelerator Report: A quench of an LHC inner triplet magnet causes a small leak with major consequences

At 1.00 a.m. + 17 seconds on Monday, 17 July, the LHC beams were dumped after only 9 minutes in collision due to a radiofrequency interlock caused by an electrical perturbation. Approximately 300 milliseconds after the beams were cleanly dumped, several superconducting magnets around the LHC quenched – i.e. they lost their superconducting state. Among these magnets were the inner triplet magnets located to the left of Point 8 (LHCb), which play a crucial role in focusing the beams for the LHCb experiment.

While this sequence of events may not happen very often during beam operation, it is not exceptional for the LHC, as occasional quenches of some superconducting magnets are to be expected.

In this particular case, the electrical perturbation caused the quench protection system (QPS) to trigger the quench heaters of the magnets concerned. These quench heaters consist of an electrical resistor embedded in the magnet coils; they are designed to heat up quickly when a localised quench occurs somewhere in the magnet, in order to effectively bring the whole magnet out of the superconducting state in a controlled and homogenous manner. During such a quench, the liquid helium in the magnet warms up and turns into a gas that is recovered by the cryogenic system to be re-liquified, ready to cool down the magnets again.

The cryostat containing the inner triplet magnets. The tiny amount of very cold helium that replaced the insulation vacuum cooled down the cryostat, causing condensation of the tunnel air on the cryostat, which then froze. Several hours later, the thin layer of ice had melted again as the cryostat returned to room temperature. (Image: CERN)

Despite this being a normal and expected behaviour, the mechanical stresses involved in this process are significant and, in very rare cases, can lead to damage. Unfortunately, in the case of the inner triplet magnet located to the left of Point 8, a small leak has appeared between the cryogenic circuit, which contains the liquid helium, and the insulation vacuum that separates the cold magnet from the warm outer vessel, known as the cryostat. This vacuum barrier is crucial for preventing heat transfer from the surrounding LHC tunnel to the interior of the cryostat (this is similar to the functioning of a thermos flask). As a result of the leak, this insulation was lost: the insulation vacuum filled with helium gas, cooling down the cryostat and causing condensation to form and freeze on the outside.

As I write, investigations are ongoing to identify the source of the leak, to allow a repair strategy to be elaborated. Nevertheless, it is clear that an intervention with the inner triplet magnet at room temperature will be required. This incident will probably have a great impact on the LHC schedule, with machine operation unlikely to resume for at least several weeks.

anschaef Thu, 07/20/2023 - 12:32 Byline Rende Steerenberg Publication Date Wed, 07/19/2023 - 12:31

50 years of giant electroweak discoveries

Half a century ago, a series of tiny tracks in a bubble chamber at CERN changed the course of particle physics. The observation of “weak neutral currents”, announced on 19 July 1973 by Paul Musset of the Gargamelle collaboration, suggested that the electromagnetic and weak forces are facets of a more fundamental electroweak interaction that ruled in the early Universe. Exploring this new sector of nature has been a core business of CERN ever since, leading to the discovery of the W and Z bosons in 1983 and culminating with the discovery of the Higgs boson in 2012.

The weak force is one of the four fundamental forces of nature, responsible for crucial processes such as radioactive beta decay. Whereas the electromagnetic force was well understood as the result of neutral photons being exchanged between charged particles, the weak interaction was harder to cast in the language of quantum theory. In the 1960s, theorists posited that the weak interaction was mediated by massive versions of the photon: the charged W boson and the neutral Z boson, both inextricably tied up with the photon of electromagnetism. The W boson enabled weak interactions that involved a rearrangement of electrical charge, while the Z boson was how uncharged particles interacted via the weak force. While the former were already known to occur, the latter had never been seen before.

As physicists mastered the art of firing intense beams of neutrinos into detectors to study fundamental interactions, searches for neutral currents became possible. By the late 1960s André Lagarrigue of LAL Orsay had proposed the world’s biggest bubble chamber, Gargamelle, named after a fictional giantess. The chamber was built by the École Polytechnique Paris in 1968 and assembled at one of the beamlines of CERN’s Proton Synchrotron. Data taking started in 1970, with first results coming in shortly after. Reflecting the focus of experimentalists at the time, the search for neutral currents was placed only eighth in Gargamelle’s top-ten physics goals.

Picking out experimental evidence for neutral currents from among numerous similar-looking events was not easy, especially with the technology of the time. Researchers needed to see both “leptonic” events (whereby a neutrino interacted with an electron in the dense gas Gargamelle was filled with) and “hadronic” events (whereby a neutrino was scattered from a proton or neutron). “I remember spending the evenings with my colleagues scanning the films on special projectors, which allowed us to observe the eight views of the chamber,” recalls Gargamelle member Donatella Cavalli from the University of Milan, who was a PhD student at the time. “When the first leptonic event was found in December 1972, we were convinced that neutral currents existed.”

Further data would reveal candidate hadronic neutral-current events, but it took time for the community to be convinced. Initially, the independent Harvard–Pennsylvania–Wisconsin–Fermilab experiment in the US confirmed Gargamelle’s findings, but when they changed their experimental set-up, the tracks vanished. Only in 1974, after further analysis by both collaborations, was the existence of neutral currents universally accepted – leading to the award of the 1979 Nobel Prize in Physics to electroweak architects Sheldon Glashow, Abdus Salam and Steven Weinberg.

Gargamelle is now an exhibit in CERN’s Van Hove Square, but physicists are still pursuing the path it opened . In providing the first evidence for electroweak theory, Gargamelle’s results guided CERN to convert the Super Proton Synchrotron into a proton–antiproton collider powerful enough to enable the UA1 and UA2 collaborations to discover the W and Z bosons directly – a feat recognised by the award of the 1984 Nobel Prize in Physics to Carlo Rubbia and Simon van der Meer of CERN. During the 1990s, precision measurements of the W and Z bosons at the Large Electron–Positron collider confirmed important “quantum corrections” to electroweak theory (which, together with the theory of the strong force, quantum chromodynamics, makes up the Standard Model of particle physics). This guided physicists towards the discovery of the final piece of the electroweak jigsaw – the Higgs boson – at the Large Hadron Collider (LHC) in 2012, which led theorists François Englert and Peter Higgs to be awarded the 2013 Nobel Prize in Physics.

But the journey does not end there. As the LHC’s ATLAS and CMS experiments continue to probe the Higgs boson and other mysterious sectors of the Standard Model at increasing levels of precision, physicists are investigating the feasibility of a successor collider at CERN – the proposed Future Circular Collider – that would go much further, opening the next chapter in electroweak exploration.

Read more in CERN Courier:

CERN's neutrino odyssey

The higgs after LHC

A scientific symposium marking 50 years of neutral currents and 40 years of the W and Z bosons will take place at CERN on 31 October 2023 in the Science Gateway Auditorium.

The Gargamelle bubble chamber now sits in the park next to Science Gateway. (Image: CERN)

 

ckrishna Wed, 07/19/2023 - 10:04 Byline Matthew Chalmers Publication Date Wed, 07/19/2023 - 10:00

50 years of giant electroweak discoveries

Half a century ago, a series of tiny tracks in a bubble chamber at CERN changed the course of particle physics. The observation of “weak neutral currents”, announced on 19 July 1973 by Paul Musset of the Gargamelle collaboration, suggested that the electromagnetic and weak forces are facets of a more fundamental electroweak interaction that ruled in the early Universe. Exploring this new sector of nature has been a core business of CERN ever since, leading to the discovery of the W and Z bosons in 1983 and culminating with the discovery of the Higgs boson in 2012.

The weak force is one of the four fundamental forces of nature, responsible for crucial processes such as radioactive beta decay. Whereas the electromagnetic force was well understood as the result of neutral photons being exchanged between charged particles, the weak interaction was harder to cast in the language of quantum theory. In the 1960s, theorists posited that the weak interaction was mediated by massive versions of the photon: the charged W boson and the neutral Z boson, both inextricably tied up with the photon of electromagnetism. The W boson enabled weak interactions that involved a rearrangement of electrical charge, while the Z boson was how uncharged particles interacted via the weak force. While the former were already known to occur, the latter had never been seen before.

As physicists mastered the art of firing intense beams of neutrinos into detectors to study fundamental interactions, searches for neutral currents became possible. By the late 1960s André Lagarrigue of LAL Orsay had proposed the world’s biggest bubble chamber, Gargamelle, named after a fictional giantess. The chamber was built by the École Polytechnique Paris in 1968 and assembled at one of the beamlines of CERN’s Proton Synchrotron. Data taking started in 1970, with first results coming in shortly after. Reflecting the focus of experimentalists at the time, the search for neutral currents was placed only eighth in Gargamelle’s top-ten physics goals.

Picking out experimental evidence for neutral currents from among numerous similar-looking events was not easy, especially with the technology of the time. Researchers needed to see both “leptonic” events (whereby a neutrino interacted with an electron in the dense gas Gargamelle was filled with) and “hadronic” events (whereby a neutrino was scattered from a proton or neutron). “I remember spending the evenings with my colleagues scanning the films on special projectors, which allowed us to observe the eight views of the chamber,” recalls Gargamelle member Donatella Cavalli from the University of Milan, who was a PhD student at the time. “When the first leptonic event was found in December 1972, we were convinced that neutral currents existed.”

Further data would reveal candidate hadronic neutral-current events, but it took time for the community to be convinced. Initially, the independent Harvard–Pennsylvania–Wisconsin–Fermilab experiment in the US confirmed Gargamelle’s findings, but when they changed their experimental set-up, the tracks vanished. Only in 1974, after further analysis by both collaborations, was the existence of neutral currents universally accepted – leading to the award of the 1979 Nobel Prize in Physics to electroweak architects Sheldon Glashow, Abdus Salam and Steven Weinberg.

Gargamelle is now an exhibit in CERN’s Van Hove Square, but physicists are still pursuing the path it opened . In providing the first evidence for electroweak theory, Gargamelle’s results guided CERN to convert the Super Proton Synchrotron into a proton–antiproton collider powerful enough to enable the UA1 and UA2 collaborations to discover the W and Z bosons directly – a feat recognised by the award of the 1984 Nobel Prize in Physics to Carlo Rubbia and Simon van der Meer of CERN. During the 1990s, precision measurements of the W and Z bosons at the Large Electron–Positron collider confirmed important “quantum corrections” to electroweak theory (which, together with the theory of the strong force, quantum chromodynamics, makes up the Standard Model of particle physics). This guided physicists towards the discovery of the final piece of the electroweak jigsaw – the Higgs boson – at the Large Hadron Collider (LHC) in 2012, which led theorists François Englert and Peter Higgs to be awarded the 2013 Nobel Prize in Physics.

But the journey does not end there. As the LHC’s ATLAS and CMS experiments continue to probe the Higgs boson and other mysterious sectors of the Standard Model at increasing levels of precision, physicists are investigating the feasibility of a successor collider at CERN – the proposed Future Circular Collider – that would go much further, opening the next chapter in electroweak exploration.

Read more in CERN Courier:

CERN's neutrino odyssey

The higgs after LHC

A scientific symposium marking 50 years of neutral currents and 40 years of the W and Z bosons will take place at CERN on 31 October 2023 in the Science Gateway Auditorium.

The Gargamelle bubble chamber now sits in the park next to Science Gateway. (Image: CERN)

 

ckrishna Wed, 07/19/2023 - 10:04 Publication Date Wed, 07/19/2023 - 10:00

Computer Security: Fighting spam – the Boss Level

When it comes to protecting mailboxes against unwanted, unsolicited or even malicious emails, spam filtering is the first line of defence. And spam filtering is, while being a permanent fight against the windmill à la Don Quixote or against boulders and gravity à la Sisyphus, reasonably easy: you just need to have the right patterns of wrong emails to filter them out. The real challenge comes afterwards: identifying emails with malicious content hidden behinds links, URLs or within attachments – the malware detection and detonation part. Let’s enter the Boss Level (like in any great movie or video game).  

Actually, it’s easy to complain about spam filtering when receiving emails which are obviously spam, full of typos, of no relevance or simply and plainly dumb and stupid. On the other hand, training the spam filter is complicated and complex, in particular in an Organization like CERN where emails come from all corners of the planet, are written and read in all languages of the world, and are answered day and night. It’s even more complicated given that CERN allows personal use of the @cern.ch email address, meaning that it receives not only professional and work-related emails but also personal exchanges, private invoices, advertising and newsletters, some directly, some forwarded from external mail hosting services like Gmail or from your institute’s mail system. Finding the right balance between true spam emails to be rejected and those where some doubt remains is difficult, and as the CERN mail service prefers to be transparent, in case of doubt, emails are delivered either to your junk folder or withheld in the spam system’s quarantine. But before delivery, there’s one more step. Here comes the Superboss.  

Evil attackers are permanently out to trick you. To convince you to click on that one malicious link, to open that one malicious attachment. One click and your password might be at risk, your computer infected, or your work or private life in peril. Ideally, such emails won’t ever make it into your mailbox thanks to our sophisticated “email detonation” appliances. For each suspicious email, these appliances spawn up virtual machines with different operating system flavours (Windows 10, Windows 11, etc.), open the suspicious email and simulate user interactions – clicking, opening attachments, mouse movements. You get it. They wait to see whether the email, the clicked link or the attachment does something unexpected ─ whether it “detonates”… This includes contacting external IP addresses, downloading external files or manipulating operating system settings or the file system, i.e. actions you wouldn’t expect when just reading an email or an attached PDF. If it detonates, quarantining that email is advised. Master the Boss Rush, defeat the Bosses. Over and over again. Like Don Quixote or Sisyphus.

CERN’s mail service and Computer Security team are currently deploying a new Boss fighter, Xorlab’s “ActiveGuard”. ActiveGuard complements Microsoft’s spam filter (Microsoft Exchange Online Protection, “EOP”) and is intended to replace Microsoft’s native solution, Microsoft Defender for Office (MDO), which was showing deficiencies when compared in detection quality with our previous solution from FireEye*. ActiveGuard is an in-line cloud solution for email protection, malware identification and containment, and malicious attachment detonation. It also comes with security enhancements based on commonly used industrial standards, namely DMARC validation. While this might break certain functionalities (like external mailing lists spoofing cern.ch email addresses), these standards significantly improve the security of any email exchange by preventing email sender spoofing. And fighting the Boss requires the right weapons…

All email users will benefit from the additional email protection provided by this Boss fighter. However, especially at the beginning while we’re still fine-tuning the filtering of EOP and ActiveGuard, you might see a bit more unwanted mail either quarantined or delivered to your junk folder. In addition, another slight drawback we’re still working on is that both solutions, EOP and ActiveGuard, provide you independently with information about the emails quarantined by them so that you can review and decide whether or not release them yourself. During the roll-out phase we hope to tune this in such a way that the number of false positives to be reviewed by you (and those to be reviewed by us!) reach an acceptable minimum. Have patience with us if we don’t get it quite right at first, and be comforted by the fact that these new spam and malware appliances effectively and efficiently fight the Bosses for you!

* MDO was detecting only about 5–50% when forwarded the quarantined messages from FireEye, which have a very high true positive rate. Six months of discussion with Microsoft support have not resolved this discrepancy. With the new solution, we will repeat this exercise. However, what the (security) world might need is a “Virustotal” for email security products.

_____

Do you want to learn more about computer security incidents and issues at CERN? Follow our Monthly Report. For further information, questions or help, check our website or contact us at Computer.Security@cern.ch.

anschaef Tue, 07/18/2023 - 12:46 Byline Computer Security team Publication Date Tue, 07/18/2023 - 12:43

Computer Security: Fighting spam – the Boss Level

When it comes to protecting mailboxes against unwanted, unsolicited or even malicious emails, spam filtering is the first line of defence. And spam filtering is, while being a permanent fight against the windmill à la Don Quixote or against boulders and gravity à la Sisyphus, reasonably easy: you just need to have the right patterns of wrong emails to filter them out. The real challenge comes afterwards: identifying emails with malicious content hidden behinds links, URLs or within attachments – the malware detection and detonation part. Let’s enter the Boss Level (like in any great movie or video game).  

Actually, it’s easy to complain about spam filtering when receiving emails which are obviously spam, full of typos, of no relevance or simply and plainly dumb and stupid. On the other hand, training the spam filter is complicated and complex, in particular in an Organization like CERN where emails come from all corners of the planet, are written and read in all languages of the world, and are answered day and night. It’s even more complicated given that CERN allows personal use of the @cern.ch email address, meaning that it receives not only professional and work-related emails but also personal exchanges, private invoices, advertising and newsletters, some directly, some forwarded from external mail hosting services like Gmail or from your institute’s mail system. Finding the right balance between true spam emails to be rejected and those where some doubt remains is difficult, and as the CERN mail service prefers to be transparent, in case of doubt, emails are delivered either to your junk folder or withheld in the spam system’s quarantine. But before delivery, there’s one more step. Here comes the Superboss.  

Evil attackers are permanently out to trick you. To convince you to click on that one malicious link, to open that one malicious attachment. One click and your password might be at risk, your computer infected, or your work or private life in peril. Ideally, such emails won’t ever make it into your mailbox thanks to our sophisticated “email detonation” appliances. For each suspicious email, these appliances spawn up virtual machines with different operating system flavours (Windows 10, Windows 11, etc.), open the suspicious email and simulate user interactions – clicking, opening attachments, mouse movements. You get it. They wait to see whether the email, the clicked link or the attachment does something unexpected ─ whether it “detonates”… This includes contacting external IP addresses, downloading external files or manipulating operating system settings or the file system, i.e. actions you wouldn’t expect when just reading an email or an attached PDF. If it detonates, quarantining that email is advised. Master the Boss Rush, defeat the Bosses. Over and over again. Like Don Quixote or Sisyphus.

CERN’s mail service and Computer Security team are currently deploying a new Boss fighter, Xorlab’s “ActiveGuard”. ActiveGuard complements Microsoft’s spam filter (Microsoft Exchange Online Protection, “EOP”) and is intended to replace Microsoft’s native solution, Microsoft Defender for Office (MDO), which was showing deficiencies when compared in detection quality with our previous solution from FireEye*. ActiveGuard is an in-line cloud solution for email protection, malware identification and containment, and malicious attachment detonation. It also comes with security enhancements based on commonly used industrial standards, namely DMARC validation. While this might break certain functionalities (like external mailing lists spoofing cern.ch email addresses), these standards significantly improve the security of any email exchange by preventing email sender spoofing. And fighting the Boss requires the right weapons…

All email users will benefit from the additional email protection provided by this Boss fighter. However, especially at the beginning while we’re still fine-tuning the filtering of EOP and ActiveGuard, you might see a bit more unwanted mail either quarantined or delivered to your junk folder. In addition, another slight drawback we’re still working on is that both solutions, EOP and ActiveGuard, provide you independently with information about the emails quarantined by them so that you can review and decide whether or not release them yourself. During the roll-out phase we hope to tune this in such a way that the number of false positives to be reviewed by you (and those to be reviewed by us!) reach an acceptable minimum. Have patience with us if we don’t get it quite right at first, and be comforted by the fact that these new spam and malware appliances effectively and efficiently fight the Bosses for you!

* MDO was detecting only about 5–50% when forwarded the quarantined messages from FireEye, which have a very high true positive rate. Six months of discussion with Microsoft support have not resolved this discrepancy. With the new solution, we will repeat this exercise. However, what the (security) world might need is a “Virustotal” for email security products.

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Do you want to learn more about computer security incidents and issues at CERN? Follow our Monthly Report. For further information, questions or help, check our website or contact us at Computer.Security@cern.ch.

anschaef Tue, 07/18/2023 - 12:46 Byline Computer Security team Publication Date Tue, 07/18/2023 - 12:43

92 companies from across CERN Member and Associate Member States take part in CERN’s thematic forum on civil engineering CERN's first Civil Engineering Business Forum took place on 24 and 25 May. (Image: CERN)

On 24 and 25 May, CERN held its first Civil Engineering Business Forum. This industry-specific event was launched as part of the Laboratory’s new approach to engaging with a variety of businesses, focused on a specific domain, from Member and Associate Member States. The new format allows for better business alignment and for greater interaction between CERN’s suppliers, experts and procurement officers.

The forum was held in hybrid format, allowing a range of companies across the spectrum of civil engineering and construction to discover CERN’s site and civil engineering plans and practices. The event saw broad participation from 92 companies representing 12 Member and Associate Member States, with over 50% of attendees coming on site. At least 50 one-to-one in-person meetings between companies and CERN representatives took place.

“I was delighted to see the enthusiastic interactions during the event. The fact that it was focused on a specific theme allowed all involved – potential suppliers, CERN technical experts and procurement officers – to have meaningful conversations about our civil engineering needs and how industry can be involved,” says Luz Anastasia Lopez, Leader of CERN’s Site and Civil Engineering Project Portfolio Management group.

The primary objectives of this new type of event are to:

1. Assist industry from all Member and Associate Member States in aligning with CERN's business needs and developing opportunities for collaboration.
2. Optimise and facilitate crucial interactions between suppliers and CERN's technical teams in a structured and targeted manner.
3. Increase competition by sourcing new suppliers.
4. Foster technological awareness and gather early feedback on industry capabilities and interest in specific projects.
5. Facilitate connections among suppliers to encourage the formation of consortia and the development of subcontractor networks.

CERN’s Procurement group has also introduced market survey conferences, providing an avenue for relevant companies from Member and Associate Member States to learn about upcoming projects and calls for tender. The inaugural virtual conference, which took place in January 2023, focused on the purchase of cables for the High-Luminosity Large Hadron Collider (HL-LHC). The event made it possible to identify new suppliers, as well as to gather valuable feedback from the participating companies on specific technical considerations.

The successful execution of these events sets the stage for future industry engagement techniques, ensuring the continued growth and development of cutting-edge scientific research at CERN.

anschaef Tue, 07/18/2023 - 12:04 Byline Marzena Lapka Lisa Bellini-Devictor Publication Date Tue, 07/18/2023 - 12:01

ALICE honours its PhD thesis award winners

On 12 July 2023, the ALICE collaboration celebrated its PhD thesis award winners in a ceremony organised as part of the ALICE collaboration meeting at CERN. Since 2008, ALICE has recognised the most outstanding PhD theses in the fields of physics and instrumentation based on the excellence of the results obtained, the quality of the thesis manuscript, and the importance of the contribution to the collaboration.

The quality of all 21 theses submitted for the award this year has been excellent. After reviewing all the theses, the ALICE Thesis Award committee unanimously decided to honour two winners:

• Rita Sadek of Laboratoire Subatech, France for her thesis on “MFT commissioning and preparation for Run 3 data analysis with ALICE (LHC, CERN)”. Rita is now a PostDoc with the LHCb collaboration at LLR Palaiseau.
• Lucas Anne Vermunt of Utrecht University, The Netherlands, for his thesis on “Hadronisation of heavy quarks - Production measurements of heavy-flavour hadrons from small to large collision systems”. Lucas is now a PostDoc with ALICE at GSI Darmstadt.

Both winners received congratulations by the ALICE Spokesperson, Marco van Leeuwen, the Collaboration Board Chair, Marielle Chartier, and the Chair of the Thesis Award committee, Ralf Averbeck. Marco and Marielle handed over the award certificates and prizes to Rita and Luuk, who presented their thesis works in flash talks to the collaboration.

Further details on the ALICE Collaboration website.

thortala Tue, 07/18/2023 - 09:20 Byline ALICE collaboration Publication Date Tue, 07/18/2023 - 09:19

Preparing for a quantum leap: researchers chart future for use of quantum computing in particle physics

Last week, researchers published an important white paper identifying activities in particle physics where burgeoning quantum-computing technologies could be applied. The paper, authored by experts from CERN, DESY, IBM Quantum and over 30 other organisations, is now available on ArXiv.

With quantum-computing technologies rapidly improving, the paper sets out where they could be applied within particle physics in order to help tackle computing challenges related not only to the Large Hadron Collider’s ambitious upgrade programme, but also to other colliders and low-energy experiments worldwide.

The paper was produced by a working group set up at the first-of-its-kind “QT4HEP” conference, held at CERN last November. Over the last eight months, the 46 members of this working group have worked hard to identify areas where quantum-computing technologies could provide a significant boon.

The areas identified relate to both theoretical and experimental particle physics. The paper then maps these areas to “problem formulations” in quantum computing. This is an important step in ensuring that the particle physics community is well positioned to benefit from the massive potential of breakthrough new quantum computers when they come online.

“Quantum computing is very promising, but not every problem in particle physics is suited to this mode of computing,” says Alberto Di Meglio, head of the CERN Quantum Technology Initiative (CERN QTI) and one of the paper’s lead authors, alongside DESY’s Karl Jansen and IBM Quantum’s Ivano Tavernelli. “It’s important to ensure that we are ready and that we can accurately identify the areas where these technologies have the potential to be most useful for our community.”

As far as theoretical particle physics is concerned, the authors have identified promising areas related to evolution of the quantum states, lattice-gauge theory, neutrino oscillations and quantum field theories in general. The applications considered include quantum dynamics, hybrid quantum/classical algorithms for static problems in lattice gauge theory, optimisation and classification.

On the experimental side, the authors have identified areas related to jet and track reconstruction, extraction of rare signals, for-and-beyond Standard Model problems, parton showers and experiment simulation. These are then mapped to classification, regression, optimisation and generation problems.

Members of the working group behind this paper will now begin the process of selecting specific use cases from the activities listed in the paper to be taken forward through CERN’s and DESY’s participation in the IBM Quantum Network, and through collaboration with IBM Quantum, under its “100x100 Challenge”. IBM Quantum is long-standing collaborator of CERN QTI and the Center for Quantum Technologies and Applications (CQTA) at DESY. 

IBM’s 100x100 Challenge will see the company provide a tool capable of calculating unbiased observables of circuits with 100 qubits and depth-100 gate operations in 2024. This will offer an important testbed for taking forward promising selected use cases from both particle physics and other research fields.

The working group will meet again at CERN for a special workshop on 16 and 17 November, immediately before the Quantum Techniques in Machine Learning conference is held at the Laboratory from 19 to 24 November.

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A longer version of this article is available on the CERN QTI website.

Read the full paper on ArXiv here.

abelchio Mon, 07/17/2023 - 16:28 Byline Andrew Purcell Publication Date Mon, 07/17/2023 - 16:27

CERN Science Gateway: architecture at the service of knowledge

Throughout CERN’s almost 70-year history, architecture has been placed at the service of science through iconic structures built on the Laboratory’s sites. As the Science Gateway building – designed by renowned Italian architect Renzo Piano – is nearing completion, we explore how these grand architectural projects have shaped the Organization since its early days.

Building 60, on the Meyrin site, is currently undergoing renovations to make it fit for the 21st century while respecting the architect's vision (Image: CERN)

The original CERN complex, dating from the 1950s and centred around its Main Building, established the Laboratory’s strong architectural identity. The Zurich-based architects in charge of the project, Rudolf and Peter Steiger, sought primarily to tie in with the “international Geneva” architectural movement that, in the aftermath of the Second World War, was injecting a spirit of modernity and renewal into institutions such as the World Health Organization and the International Labour Office by means of monumental, utilitarian and sculptural structures. We find this monumental character in CERN’s Main Building and Building 60, as well as in the experimental halls and neighbouring buildings that the architects sought to harmonise, all linked by an architectural unity emphasising exposed reinforced concrete. In short, the architecture of the original complex reflected the coherence of the Laboratory’s project, in which the services and communities revolved around a unified, communal space.

The building 40 atrium, featuring the CMS poster (Image: CERN)

Over the years, CERN has added other iconic buildings, such as Building 40 with its vast central atrium, completed in 1996, and its extension, Building 42, completed in 2011 and now the seat of the CERN Directorate. Both of these buildings were designed by architect Jacques Perret. In addition, the Globe of Science and Innovation, initially built for the Swiss National Exhibition in 2002 and presented to CERN to mark its 50th anniversary, has since become a symbol of the Organization and the surrounding area.

More recently, the Prévessin site has welcomed some ambitious and environmentally minded architectural projects, such as Building 774, designed by architects Octavio Mestre and Francesco Soppelsa. Inaugurated in 2015, its innovative design includes a façade covered with solar panels based on CERN technology. It sits opposite the new data centre, which will use cutting-edge cooling technologies and recover the thermal energy generated by the computing infrastructure to heat other buildings on the site.

But all eyes are now on Science Gateway, whose inauguration is due to take place in October. Patrick Geeraert, Science Gateway Project Leader, recalls how this vast undertaking began: “When Renzo Piano presented his model to us in 2018, in his Genoa offices, it turned all our plans upside down. The project was as magnificent as it was ambitious.” The proposal would go on to take the form of a structure divided into three pavilions and two imposing tubes connected by a suspended walkway.

Outreach centre... or space station? (Image: CERN)

The strong symbolism of the two tubes suspended over the road is unmissable: Renzo Piano intended them to mirror the LHC tunnel, located 100 metres below. They will immerse visitors in the world of particle accelerators before they even enter the building. In another nod to the universe of science, the silhouette of Science Gateway seen from above recalls that of a space station that has landed in a forest. With 400 trees planted especially, this forest is another key feature of the project, underlining the close links between science and nature. Lastly, the materials chosen and the overall aesthetic of the building, with its raw forms and exposed concrete, celebrate – rather than try to conceal – CERN’s industrial character.

Five years and one pandemic later, with the support of the ICM and Cimolai consortia, the dream has become a reality and CERN is preparing to open even more to the world thanks to its new centre. Just a few months away from the opening, Patrick Geeraert has plenty to be happy about: “A few years ago, we couldn’t have dreamed of building such a structure in such a short time and without impinging on the CERN Budget. The project has been financed entirely by donations, and I’d like to thank our sponsors once again, as well as all the CERN teams who have helped to make Science Gateway a reality.”

Without a shadow of a doubt, Science Gateway will be much more than just an exhibition centre; it will be a hub where science is brought to life, the scientific comminuty is welcomed and the wellspring of ideas that has characterised CERN for almost 70 years will be nurtured. Grand architectural projects marked the Organization’s early days and will help usher in its future.

thortala Mon, 07/17/2023 - 10:24 Byline Thomas Hortala Publication Date Mon, 07/17/2023 - 10:23

GBAR joins the anticlub

The aim of the GBAR experiment at CERN is to measure the acceleration of an antihydrogen atom – the simplest form of atomic antimatter – in Earth's gravitational field, and to compare it with that of the normal hydrogen atom. Such a comparison is a crucial test of Einstein's equivalence principle, which states that the trajectory of a particle is independent of its composition and internal structure when it is only subjected to gravitational forces.

But producing and slowing down an antiatom enough to see it in free fall is no mean feat. GBAR's approach is to first produce an antihydrogen atom and then turn it into a positive ion (the antimatter equivalent of an H- ion). Then the ion can be slowed down using quantum-optical techniques. Finally, the ion is neutralised for free-fall measurement. In a new paper, the GBAR collaboration reports the successful production of its first antiatoms.

To achieve this, the team has developed a complex protocol in which antihydrogen atoms are assembled from antiprotons produced by the Antiproton Decelerator (AD) and positrons produced in GBAR. The AD's 5.3-MeV antiprotons are decelerated and cooled in the ELENA ring and a packet of a few million 100-keV antiprotons is sent to GBAR every two minutes. In GBAR, a device called a pulsed drift tube further decelerates this packet to an adjustable energy of a few keV. In parallel, in another part of GBAR, a linear particle accelerator sends 9-MeV electrons onto a tungsten target, producing positrons, which are accumulated in a series of electromagnetic traps. Just before the antiproton packet arrives, the positrons are sent to a layer of nanoporous silica, from which about one in five positrons emerges as a positronium atom (the bound state of a positron and an electron). When the antiproton packet crosses the resulting cloud of positronium atoms, a charge exchange can take place, with the positronium giving up its positron to the antiproton, forming antihydrogen.

At the end of 2022, during an operation that lasted several days, the GBAR collaboration detected some 20 antihydrogen atoms produced in this way, validating this "in-flight" production method for the first time.

After this essential first step, the collaboration will now improve the production of antihydrogen atoms. This will enable precision measurements to be made on the antihydrogens themselves, in particular a measurement of an energy gap between two specific atomic levels, known as the Lamb shift. This measurement will give a more precise value of the radius of the antiproton. This will be followed by the production of positive antihydrogen ions, and finally by the implementation of the laser systems for cooling and neutralising these ions in order to finally observe the free fall of an antihydrogen atom.

GBAR is not the first experiment to produce antihydrogen: in 1995, an experiment at CERN's LEAR facility produced nine antiatoms, but at an energy too high for any measurement to be made. Following this early success, CERN's Antiproton Accumulator (used for the discovery of the W and Z bosons in 1983) was repurposed as a decelerator, becoming the AD, which is unique worldwide in providing low-energy (5-MeV) antiprotons to antimatter experiments. After the demonstration of holding antiprotons by the ATRAP and ATHENA experiments, ALPHA, a successor of ATHENA, was the first experiment to merge trapped antiprotons and positrons and to trap the resulting antihydrogen atoms. Since then, ATRAP and ASACUSA have also achieved these two milestones, and AEgIS has produced pulses of antiatoms. GBAR now joins this elite club, having produced 6-keV antihydrogen atoms in flight.

GBAR is also not alone in its aim of testing Einstein’s equivalence principle with atomic antimatter. ALPHA and AEgIS are also working towards this goal using other approaches.

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This text is a modified version of a story originally published in French here. 

abelchio Fri, 07/14/2023 - 12:41 Publication Date Fri, 07/14/2023 - 12:40

An evening dedicated to neutrinos in Prévessin-Moëns

CERN, the Prévessin-Moëns local authorities and the village’s municipal library joined forces to enable local residents to find out more about what goes on inside the Laboratory, with a particular focus on neutrinos.

Neutrinos are invisible particles, almost devoid of mass, which pass through matter like ghosts and behave unexpectedly at the quantum level. Their identity-shifting ability could help answer some of the great mysteries surrounding the origins of the Universe.

The evening kicked off with a screening at the Prévessin-Moëns municipal library of the film Ghost Particle, directed by Geneva Guérin. This scientific documentary explores the research going on worldwide to trace the origins of the Universe by studying its tiniest components, neutrinos, in some of the biggest experiments in existence.

The film was followed by a tour of the Prévessin site guided by CERN scientists. The visitors got a chance to visit the CERN Control Centre and the Neutrino Platform, a facility where the international community of neutrino specialists is developing the next generation of neutrino detectors.

The platform, which is located in the commune of Prévessin-Moëns, is CERN’s main contribution to the DUNE experiment, a globally coordinated neutrino programme.

To find out more about this programme, check out the livestream video from the CERN Neutrino Platform, the Fermi National Accelerator Laboratory and the Sanford Underground Research Facility: https://videos.cern.ch/record/2298268.

For more information about the CERN Neutrino Platform, visit: https://home.cern/science/experiments/cern-neutrino-platform

thortala Thu, 07/13/2023 - 09:31 Publication Date Thu, 07/13/2023 - 09:29

Sneak a peek into Science Gateway

Three immersive, hands-on exhibitions take up the tubes that mimic the LHC tunnel and the pavilion connected to Van Hove Square, which houses former detectors and detector parts. One tube is home to Our Universe, which along one side draws a timeline from the present-day structure of our cosmos all the way back to the Big Bang. On the other side, Exploring the Unknown features four installations by artists from around the world who collaborate with Arts at CERN. Their aim is to inspire a new way of thinking about the mysteries of the Universe. The other tube – Discover CERN – answers many of the questions you may have about how to study particles and how accelerators work. Lastly, in another of the pavilions, visitors will come face to face with particle scales and phenomena through which to experience the Quantum World.

On the first floor of the reception pavilion are the Labs, where school groups, families and individual visitors will be encouraged to work together and carry out hands-on experiments under the supervision of CERN Guides, who will also be on hand to interact with visitors in the exhibitions in many different ways.

The building complex includes a new auditorium. Able to accommodate 900 people, it can be split into three separate spaces depending on the desired format. In addition to hosting collaboration meetings of CERN’s experiments, scientific announcements and outside-hire events, the auditorium pavilion will also be the venue for regular public events and science shows. Taking the form of interactive theatre-like performances led by CERN Guides, the science shows will explain science in a fun way for all audiences.

After your tour, the Big Bang café in the reception pavilion is an invitation to stop off for refreshments, which can be enjoyed in the park surrounding the complex. Lastly, to round off the many memories made at Science Gateway, the shop offers all kinds of souvenirs, allowing you to continue the journey.

CERN Science Gateway will have something for everyone aged 5 or over, interested in science, CERN, architecture or learning.

ndinmore Tue, 07/11/2023 - 09:44 Byline Sanje Fenkart Publication Date Wed, 07/26/2023 - 09:26

Sneak a peek into Science Gateway

Three immersive, hands-on exhibitions take up the tubes that mimic the LHC tunnel and the pavilion connected to Van Hove Square, which houses former detectors and detector parts. One tube is home to Our Universe, which along one side draws a timeline from the present-day structure of our cosmos all the way back to the Big Bang. On the other side, Exploring the Unknown features four installations by artists from around the world who collaborate with Arts at CERN. Their aim is to inspire a new way of thinking about the mysteries of the Universe. The other tube – Discover CERN – answers many of the questions you may have about how to study particles and how accelerators work. Lastly, in another of the pavilions, visitors will come face to face with particle scales and phenomena through which to experience the Quantum World.

On the first floor of the reception pavilion are the Labs, where school groups, families and individual visitors will be encouraged to work together and carry out hands-on experiments under the supervision of CERN Guides, who will also be on hand to interact with visitors in the exhibitions in many different ways.

The building complex includes a new auditorium. Able to accommodate 900 people, it can be split into three separate spaces depending on the desired format. In addition to hosting collaboration meetings of CERN’s experiments, scientific announcements and outside-hire events, the auditorium pavilion will also be the venue for regular public events and science shows. Taking the form of interactive theatre-like performances led by CERN Guides, the science shows will explain science in a fun way for all audiences.

After your tour, the Big Bang café in the reception pavilion is an invitation to stop off for refreshments, which can be enjoyed in the park surrounding the complex. Lastly, to round off the many memories made at Science Gateway, the shop offers all kinds of souvenirs, allowing you to continue the journey.

CERN Science Gateway will have something for everyone aged 5 or over, interested in science, CERN, architecture or learning.

ndinmore Tue, 07/11/2023 - 09:44 Byline Sanje Fenkart Publication Date Wed, 07/26/2023 - 09:26

Arts at CERN collaborates with Science Gallery Melbourne and the ARC Centre for the exhibition “Dark Matters”

Arts at CERN has joined forces with Science Gallery Melbourne and the ARC Centre of Excellence for Dark Matter Particle Physics to present Dark Matters, an exhibition that seeks to explore the fundamental essence of life and the Universe and to question how their mysteries continue to elude us. For over a decade, Arts at CERN has been actively developing international collaborations with leading scientific laboratories and cultural institutions to foster a global network of art and science. Through Dark Matters, Arts at CERN extends this commitment by igniting dialogues between artists and experts from the ARC Centre of Excellence for Dark Matter Particle Physics, Australia’s leading dark matter research centre.

In 2017, Arts at CERN launched its exhibitions programme with the aim of engaging with audiences who are interested in art and fundamental science and eager to connect with CERN’s research. Now, Dark Matters brings some of the remarkable creations that have emerged from the work and research of the artists-in-residence to connect with and inspire audiences across Melbourne.

Physicists estimate that we can see and interact with only 5% of the mass of the Universe; the rest remains little known. About 85% of this unseen mass is attributed to dark matter, which is particularly challenging to study because it does not visibly interact with light. As artists and scientists continue the ultimate quest to understand it, its elusive nature mirrors the limitations of our cognitive experience. Dark Matters poses the question of whether searching for this mysterious substance could lead us to imagine new possibilities for life, our relationship with non-humans, and creative technologies that enable us to access unfathomable environments.

Several artworks in the exhibition have been drawn from Arts at CERN’s residency programmes. South Korean music producer and artist Yunchul Kim presents Chroma V, a giant 50-metre-long sculpture that folds in on itself in an intricate knot. Made of metal and materials derived from techniques Kim explored in collaboration with material scientists, the installation detects subatomic particles and comes to life as it reacts to invisible forces. 2016 Collide awardee Kim will also premiere a new art commission in an upcoming exhibition at the CERN Science Gateway from October.

In the project Scientific Dreaming, British artist Suzanne Treister carried out a series of writing workshops with scientists from CERN and the University of Melbourne with the aim of opening their unconscious imaginations. Through interviews and exercises, the scientists wrote science fiction stories that envisage hopeful futures based on hypothetical scientific breakthroughs, while exposing the potential risks associated with these technological advances. The stories, as well as narrative plot diagrams by the artist, will be part of the exhibition.

Dark Matters will also feature the work of Swiss artist Alan Bogana, Chilean artist Patricia Domínguez, Lithuanian designer Julijonas Urbonas and British artist duo Semiconductor among other local and international artists.

Co-curated by Mónica Bello, Head of Arts at CERN, Tilly Boleyn, Head of Curatorial at Science Gallery Melbourne, and a panel of young people and academic experts, Dark Matters will consider how dark matter changes how we think about ourselves, on both an individual level and a universal scale.

ndinmore Mon, 07/10/2023 - 10:49 Byline Ana Prendes Publication Date Mon, 07/10/2023 - 10:36

Accelerator Report: Reviving antimatter physics and fine-tuning luminosity measurements in the LHC

On Friday, 30 June, an exciting milestone was reached: the much-awaited antiproton physics season finally commenced. Originally scheduled for 11 May, the start had to postponed due to an unforeseen water leak that occurred on 14 March in a special quadrupole magnet located in the Antiproton Decelerator (AD) machine. As a result, the magnet had to be removed for repair in the workshop before being reinstalled to finalise hardware and beam commissioning. Consequently, the start of antimatter physics was rescheduled for 30 June. The AD-ELENA operations team, together with many experts, have been working hard to meet – with success – this important deadline.

The delay caused by the leaking magnet resulted in a loss of 50 physics days for the experiments behind the ELENA machine. To partially compensate for this significant loss of precious physics time, the 2023 run for the antimatter factory has been extended by 12 days. The extended run will now conclude at 6 a.m. on 13 November. This adjustment is intended to maximise scientific output and make best use of the available time for the experiments, without compromising on the many activities scheduled for the 2023–2024 year-end technical stop (YETS).

On the LHC side, the technical stop mentioned in the last Accelerator Report has been successfully completed. Following the stop, special physics runs were conducted along with a short intensity ramp-up to revalidate the LHC machine for luminosity production. Despite some delays caused by technical issues, including a power cut affecting part of CERN, the machine has now resumed normal operation with the aim of maximising luminosity production.

One of the special physics runs was the so-called “van der Meer” run, which plays a crucial role in precisely calibrating the experiments’ luminosity measurements. This calibration involves establishing a precise relationship between the beam separation and the observed rate of particle interactions. During the van der Meer scan, the separation between the colliding beams is intentionally varied, leading to changes in the number of particle interactions. Through meticulous control of the beam separation and thorough analysis of the resulting data, the experts in the experiments can accurately determine the relationship between beam separation and observed interactions. This relationship is referred to as the “luminosity calibration curve”, which serves as vital input towards an accurate – in the order of one per cent – determination of the number of collisions recorded by the LHC experiments.

This is just one part of the LHC luminosity scan application, where the beam separation steps for the CMS van der Meer scan are clearly visible (second row of plots): on the left-hand side we see the horizontal separation, and on the right-hand side the vertical separation. The resulting luminosity is given in the bottom left-hand plot. (Image: CERN)

The LHC will continue its proton collisions and luminosity production until a brief technical stop in mid-September. Subsequently, the focus will shift to lead-ion collisions until 30 October, when the YETS is set to commence.

anschaef Thu, 07/06/2023 - 11:43 Byline Rende Steerenberg Publication Date Wed, 07/05/2023 - 11:42