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ATLAS announces its 2024 Outstanding Achievement Award winners

Cern News - Τετ, 24/07/2024 - 11:13
ATLAS announces its 2024 Outstanding Achievement Award winners

The ATLAS collaboration held its seventh biennial Outstanding Achievement Awards ceremony on 20 June 2024. These awards recognise the invaluable technical work performed across the collaboration in various fields. This year, the Awards Committee honoured two individuals and seven groups for their exceptional contributions to detector operation, detector upgrades, software, computing and teamwork during the period from February 2022 to October 2023.

“The work of the award winners demanded great creativity and determination,” said Sarah Demers, co-chair of the Awards Committee. “Not only were their contributions crucial during this recent data-taking period, but they also set the stage for high-quality physics analyses and operations in the years to come.”

Find out about the award winners on the ATLAS website.

ndinmore Wed, 07/24/2024 - 10:13 Byline ATLAS collaboration Publication Date Wed, 07/24/2024 - 10:12

Collective motion of electrons captured at the atomic scale

Nature Physics - Δευ, 22/07/2024 - 00:00

Nature Physics, Published online: 22 July 2024; doi:10.1038/s41567-024-02553-6

Many 2D or 1D materials feature fascinating collective behaviour of electrons that competes with highly localized interactions at atomic defects. By combining terahertz spectroscopy with scanning tunnelling microscopy, the ultrafast motion of these collective states can be captured with atomic spatial resolution, enabling the observation of electron dynamics at their intrinsic length and time scale.

HiLumi News: new large helium tanks

Cern News - Τετ, 17/07/2024 - 15:54
HiLumi News: new large helium tanks

Exceptional machines call for exceptional operations. Two large helium tanks for the High-Luminosity LHC (HL-LHC) were installed at Point 1 in June, and two more at Point 5 in July. They will store the helium for the refrigerators that will cool the HL-LHC’s new focusing magnets on both sides of the ATLAS and CMS experiments.

Each tank weighs over 62 tonnes and is 28 metres long and 3.5 metres in diameter. The tanks will each be able to store 250 cubic metres of gaseous helium at a pressure of 20 bars at room temperature, representing a weight of around 800 kg. As the tanks were manufactured in Portugal, it took more than eight days to transport them to CERN under escort as an abnormal load.

The new refrigerators – one for each point – will be delivered next year. “We have a good year of work ahead of us to install the complete infrastructure and connect the tanks to the helium distribution system,” explains Antonio Suraci from the Cryogenics group.

Around 130 tonnes of helium are needed to cool the superconducting magnets of the LHC and its experiments. When the HL-LHC is up and running, it will consume almost the same amount of helium, but the design of the cryogenic system will have to be modified to supply this new equipment on each side of the ATLAS and CMS experiments.


Delivery and installation of helium tanks for the High-Luminosity LHC project. (Video: CERN)


cmenard Wed, 07/17/2024 - 14:54 Publication Date Thu, 07/18/2024 - 11:40

Transverse emittance reduction in muon beams by ionization cooling

Nature Physics - Τετ, 17/07/2024 - 00:00

Nature Physics, Published online: 17 July 2024; doi:10.1038/s41567-024-02547-4

Current muon beams have a phase-space volume that is too large for applications in muon colliders. Now, the reduction in the beam’s transverse emittance when passed through different absorbers in ionization cooling experiments is quantified.

CERN and Pro Helvetia announce the artists selected for the Connect India residency

Cern News - Τρί, 16/07/2024 - 16:29
CERN and Pro Helvetia announce the artists selected for the Connect India residency

Connect is an art residency programme launched by Arts at CERN and Pro Helvetia in 2021, which serves as a platform to foster experimentation in art and science by bringing artists into contact with fundamental science and cutting-edge research at CERN and other international scientific organisations.

The two awardees, Lou Masduraud and Shailesh BR, selected by a board of cultural experts, will be invited to a three-week residency at the International Centre for Theoretical Sciences (ICTS) in Bengaluru, followed by a three-week stay at CERN in Geneva. They will receive support from the Arts at CERN and ICTS curatorial teams to explore new forms of artistic expression and transform these explorations into art productions.

Shailesh BR is a visual artist based in Delhi NCR, India. His practice explores fundamental aspects of our world by examining existing knowledge, systems, traditions and philosophical thoughts. Utilising a diverse visual vocabulary, he incorporates methods from science and technology into his artistic interventions, creating drawings, object modifications and machines.

Lou Masduraud lives and works in Geneva. Through sculpture and installation, Masduraud proposes alternative narratives to dominant realities. Her body of work explores the intricate network of human activities through formal and material investigations of everyday elements such as fountains, basement windows and pipes, in both public and private spaces.

Connect India offers these artists a unique opportunity to engage with cutting-edge fundamental scientific research in both Geneva and Bengaluru. At CERN, physicists and engineers design and use a wide array of experiments in particle physics, while ICTS focuses on theoretical sciences, encompassing fields like physics, mathematics, astronomy and computational biology.

Connect India marks the second collaboration with ICTS, following successful dual residencies at scientific organisations in Chile and South Africa. Since its launch in 2021, the Connect collaboration between Pro Helvetia and Arts at CERN has hosted seven editions and established itself as a key platform for exchange between communities of artists and scientists around the world.

ldragu Tue, 07/16/2024 - 15:29 Publication Date Thu, 07/18/2024 - 15:27

CMS congratulates its 2023 Award and Thesis Award winners

Cern News - Τρί, 16/07/2024 - 10:21
CMS congratulates its 2023 Award and Thesis Award winners CMS PhD Thesis Award winners 2023 CMS PhD Thesis Award winners 2023 (Image: CMS collaboration)

Each year, the CMS collaboration honours the work of exceptional PhD students with the Thesis Award. This award recognises doctoral research conducted within the collaboration that pushes the boundaries of high-energy physics. Out of a highly competitive pool of 27 nominees, the winners of the 2023 CMS PhD Thesis Award are Jona Motta (LLR, Institut Polytechnique de Paris), Christopher Edward Brown (Imperial College London) and Spandan Mondal (RWTH Aachen University, Germany).

“Doctoral students do a lot of impressive work in CMS. Writing a PhD thesis to document this work is a tremendous effort and achievement. Some of the students decide to invest substantial extra efforts in writing an exceptionally clear, effective and original documentation of their research work. They write for their peers, future students, who will follow in their steps, and for all those in search of in-depth, detailed, accurate but also accessible knowledge related to CMS scientific or technical frontline research,” says Marta Felcini, chair of the CMS PhD Thesis Award Committee.

Read more about the winners on the CMS website.

CMS Award winners 2023 CMS award winners 2023. (Image: CERN)

Each year since 2000, the CMS Awards Committee has recognised outstanding contributions from members of the CMS collaboration, honouring their dedication to the experiment. Nominations can be made by any CMS member for exceptional work in various fields, and the winners are selected by a dedicated committee.

“This year, the CMS Awards celebrate the hard work that was done by our collaborators both on the operations and on the upgrades to ensure the success of the present and future detector,” say the CMS Awards Committee Chairs.

As well as the 50 award winners, the RD53 collaboration was singled out by CMS for special recognition. This dedicated group is responsible for the development of the ATLAS and CMS Phase 2 inner tracker readout chips.

Find out more about the collaboration and each of the 50 awardees on the CMS website.

ndinmore Tue, 07/16/2024 - 09:21 Byline CMS collaboration Publication Date Tue, 07/16/2024 - 09:15

Water dropped in the deep end

Nature Physics - Τρί, 16/07/2024 - 00:00

Nature Physics, Published online: 16 July 2024; doi:10.1038/s41567-024-02596-9

Water dropped in the deep end

Polar rain

Nature Physics - Τρί, 16/07/2024 - 00:00

Nature Physics, Published online: 16 July 2024; doi:10.1038/s41567-024-02595-w

Polar rain

Bosons reach a century

Nature Physics - Τρί, 16/07/2024 - 00:00

Nature Physics, Published online: 16 July 2024; doi:10.1038/s41567-024-02598-7

This year marks the hundredth anniversary of Satyendra Nath Bose’s paper that stimulated the study of quantum statistics. We take this opportunity to celebrate the physics of bosons.

The kernel of thermodynamics

Nature Physics - Τρί, 16/07/2024 - 00:00

Nature Physics, Published online: 16 July 2024; doi:10.1038/s41567-024-02580-3

The kernel of thermodynamics

Cool as muons

Nature Physics - Τρί, 16/07/2024 - 00:00

Nature Physics, Published online: 16 July 2024; doi:10.1038/s41567-024-02571-4

The volume of muon beams in position–momentum space is too large to be used in a collider. A clear reduction in this volume has now been demonstrated, which brings particle physics closer to a practical muon collider for exploring the energy frontier.

LHCb investigates the properties of one of physics’ most puzzling particles

Cern News - Δευ, 15/07/2024 - 13:23
LHCb investigates the properties of one of physics’ most puzzling particles The LHCb experiment. (Image: CERN)

χc1(3872) is an intriguing particle. It was first discovered over 20 years ago in B+ meson decays by the BELLE collaboration, KEK, Japan. Since then, the LHCb collaboration reported it in 2010 and has measured some of its properties. But here’s the catch – physicists still don’t know what it is actually made up of.

In the quark model of particle physics, there are baryons (made up of three quarks), mesons (made up of a quark–antiquark pair) and exotic particles (made up of an unconventional number of quarks). To find out what χc1(3872) consists of, physicists must measure its properties, such as its mass or quantum number. Theories suggest that χc1(3872) could be a conventional charmonium state, made up of charm and anticharm quarks, or an exotic particle composed of four quarks. An exotic particle of this type could be a tightly bound tetraquark, a molecular state, a cc-gluon hybrid state, a vector glueball or a mixture of different possibilities.

Previously, the LHCb collaboration has found its quantum number to be 1++ and, in 2020, made precise measurements of the width (lifetime) and mass of the particle. The collaboration also measured what is known as its low-energy scattering parameters. The results showed that its mass is just a tad smaller than the sum of the masses of the D0 and D*0 mesons.

Following these results, the theoretical community was divided. Some argued that χc1(3872) was a molecular state consisting of spatially separated D0 and D*0 mesons. This molecular state would be much larger than the typical size of particles and more comparable to a heavy nucleus. However, this argument encounters a problem, namely that physicists expect molecular objects to be suppressed in hadron–hadron collisions, and the χc1(3872) is produced abundantly. Other theorists interpreted the results as clear evidence that χc1(3872) has a “compact” component. This would mean it is a particle with much smaller size, containing either a tightly bound charmonium or a tetraquark.

One way to help determine what χc1(3872) contains is to calculate the ratio between probabilities of the decays into different lighter particles (branching fractions). By comparing the rate at which it decays either to an excited charmonium state or to a charmonium state and a photon, physicists can gather clues as to what type of particle it is. There is a clear theoretical signature: if the ratio is non-vanishing, it is evidence for some compact component in χc1(3872), disfavouring the pure molecular model.

Now, using the complete set of LHC Run 1 and Run 2 data, the LHCb collaboration has found these ratios to be non-vanishing, with a significance exceeding six standard deviations.  The large measured value of the ratios is inconsistent with the expectations based on the pure D0D*0 molecular hypothesis for the χc1(3872) particle. Instead, it supports a wide range of predictions based on other hypotheses of the χc1(3872) structure, including conventional (compact) charmonium, a compact tetraquark containing a charm quark, charm antiquark, light quark and light antiquark, or a mixture of molecules with a substantial compact core component. In short, the result provides a strong argument in favour of the χc1(3872) structure containing a compact component.

The χc1(3872) particle continues to fascinate the particle physics community. Find out more in the paper or on the LHCb website.

ndinmore Mon, 07/15/2024 - 12:23 Byline LHCb collaboration Publication Date Tue, 07/16/2024 - 09:40

Digital archaeology: new LEP data now available to all

Cern News - Δευ, 15/07/2024 - 13:15
Digital archaeology: new LEP data now available to all

Unlike letters carved on the Rosetta stone, digital data is not written on a virtually immutable support. Just a few years after it is written, its format becomes obsolete, the readout analysis tools can’t run on computers and the visualisation code no longer works. But data can still contain interesting scientific information that should remain available to future generations of scientists.

A set of data of potentially high interest is that of LEP, CERN’s former flagship accelerator that collided electrons and positrons up until 2000. Like the current LHC, LEP had four collision points, each hosting an experiment – ALEPH, DELPHI, OPAL and L3 – that was operated by hundreds of scientists. LEP holds the record for the world’s highest e+e- energy collisions but the data collected over two decades ago remains available to only a small community of people.

Like archaeologists who unearth the remnants of past civilizations, digital archaeologists are computing experts who retrieve data years after the collaborations have moved on to other experiments. “The first step is to reach agreement within the collaboration as to opening and sharing their data and the software required to exploit it. Then, just like archaeologists, we dig into the documents that the former collaborations have written about the data architecture, and retrieve the software used for actual analysis”, explains Ulrich Schwickerath, a former DELPHI physicist and computing expert working in the IT department. This is no easy task because the information often lies in unpublished documents or in private repositories that might have not even been shared within the collaboration.

The analysis software from LEP times was deposited in CERNLIB, a CERN-developed software library that was discontinued in 2003. “Shortly after the last release of CERNLIB, many external enthusiasts kept it alive and applied quick fixes to the software, known as patches. In a community-based effort, these patches were gathered together in order to create a community version, allowing the old software to be adapted to modern architectures,” Ulrich explains. “Since then, together with a few LEP enthusiasts, we have managed to resurrect the software stacks of the DELPHI and OPAL experiments using the new community-driven version of CERNLIB. We are working towards making the dataset fully available in the original format, as compatible as possible with modern hardware and software tools, and to revise the old visualisation codes so that today's scientists can run proper analyses.”

The data from ALEPH and DELPHI is now available, and the DELPHI data is shared on the CERN Open Data Portal. So whether you're a researcher, teacher, student or just an interested non-physicist, start your discovery of electron-positron annihilation data with the DELPHI detector by visiting this webpage.



ndinmore Mon, 07/15/2024 - 12:15 Byline Antonella Del Rosso Publication Date Mon, 07/15/2024 - 12:13

Petawatt pulse pushes protons

Nature Physics - Δευ, 15/07/2024 - 00:00

Nature Physics, Published online: 15 July 2024; doi:10.1038/s41567-024-02559-0

Laser-driven acceleration is a promising path towards more compact machines. Now, proton beams with energies up to 150 MeV have been achieved with a repetitive petawatt laser.

Anyons go universal

Nature Physics - Δευ, 15/07/2024 - 00:00

Nature Physics, Published online: 15 July 2024; doi:10.1038/s41567-024-02578-x

Topological quantum computers are predicted to perform calculations by manipulating quasiparticles known as non-Abelian anyons. A type of non-Abelian anyon that supports universal quantum gates has now been simulated using superconducting qubits.

Electronic excitations at the plasmon–molecule interface

Nature Physics - Δευ, 15/07/2024 - 00:00

Nature Physics, Published online: 15 July 2024; doi:10.1038/s41567-024-02537-6

Plasmonic excitations can enhance the interaction between a metal and molecules adsorbed onto its surface. This Review summarizes the different effects involved in this process and places them into a framework based on electron scattering.

Terahertz spectroscopy of collective charge density wave dynamics at the atomic scale

Nature Physics - Δευ, 15/07/2024 - 00:00

Nature Physics, Published online: 15 July 2024; doi:10.1038/s41567-024-02552-7

The observation of phase modes of charge density wave has been a long-standing challenge. Such low-energy phase excitations have now been seen in a transition metal dichalcogenide.

On the limitations of the semi-classical picture in high harmonic generation

Nature Physics - Πέμ, 11/07/2024 - 00:00

Nature Physics, Published online: 11 July 2024; doi:10.1038/s41567-024-02579-w

High harmonic generation has long been successfully described using the semi-classical three-step model. However, recent progress has introduced a quantum optical formulation, exposing the limitations of the semi-classical picture.

Accelerator Report: No summer holidays for the accelerator complex

Cern News - Τετ, 10/07/2024 - 13:11
Accelerator Report: No summer holidays for the accelerator complex

Since the technical stop in June, Linac4 has been running quite smoothly, delivering beam to the PS Booster with good availability, of 98.7%. Despite a small water leak from the cooling system in one of the PS Booster quadrupole magnets, beam availability remains high, at 94%. The leak, though small, is being carefully managed by diverting the water outside the magnet to prevent further issues. Continuous monitoring is in place, using a camera and data from the water-cooling station. As long as the leak does not worsen, operations will proceed as usual until the end of the 2024 run. If the leak increases significantly, a spare magnet is ready for installation, which would require a beam stop of several days.

As mentioned in a previous Accelerator Report, physics at ISOLDE started on 8 April. Since then, approximately 20 different experimental runs have been conducted at the low-energy experimental stations, using various isotopes produced by impinging the high-intensity PS Booster proton beam on different types of targets. In parallel, the HIE-ISOLDE superconducting linear accelerator started the cooldown and conditioning of its 20 accelerating cavities mounted in four cryomodules and, last week, the first beams were accelerated to set up the experiments downstream. On 12 July, the physics campaign using post-accelerated isotope beams will start and continue until the end of the 2024 ISOLDE run, scheduled for 25 November.

Five superconducting cavities mounted in a cryomodule. The picture was taken in a clean room before the insertion of the cryomodule into its cryostat. (Image: CERN) The HIE-ISOLDE linear accelerator with its four cryomodules. (Image: CERN)









On the SPS side, following the successful exchange of a magnet on 18 June, the SPS resumed beam delivery for its usual clients: the North Area and the LHC. However, on 25 June, the SPS operators received an alarm indicating that some magnets in the SPS were overheating. The magnets are equipped with a magnet protection system that prevents them from being powered when their temperature rises too high, which also stops beam production.

The experts discovered that a blockage in the water-cooling circuit was causing the overheating. The circuit was unblocked and refilled on 26 June, allowing beam production to resume. The blockage was caused by pieces of rubber that had remained in the circuit following an incident earlier this year.

Since resolving this latest and ­– hopefully – last issue, the SPS has had very good beam delivery, achieving beam availability of 97% for the LHC and 93% for the North Area, making up for some of the previously lost beam time. Additionally, the HiRadMat run, initially scheduled from 1 to 5 July, was already successfully completed by 2 July, allowing additional beam time for the North Area experiments.

The LHC resumed beam production on 28 June, after bringing forward some machine development (MD) activities to give the ATLAS experiment a chance to recover from a cryogenic cooling issue. Since then, the luminosity production has been good, although the beams have often been dumped prematurely due to various unrelated and mostly minor technical issues. Despite this, the LHC had a machine availability of 70% last week, with the time spent in colliding-beams mode (i.e. stable beam ratio) of 51.3%, slightly above our target of 50%.

The integrated luminosity forecast (green line) with the achieved integrated luminosity for ATLAS (blue dots) and CMS (black dots). The difference between the two experiments is mainly due to ATLAS’s cryogenic cooling issue. The fact that both are below the green line is mainly due to the advanced MD activities and the technical issues encountered, resulting in shorter stable beam periods and more frequent filling. Physics time will be recovered later, as the next MD block will be shorter. (Image: CERN) anschaef Wed, 07/10/2024 - 12:11 Byline Rende Steerenberg Publication Date Thu, 07/11/2024 - 10:10

How can I use CERN’s Open Science Office?

Cern News - Τετ, 10/07/2024 - 10:45
How can I use CERN’s Open Science Office? Why should I care about open science?

The aim of open science is to make scientific research more accessible, transparent and efficient for the benefit of scientists and society. It includes making the products of research openly available – i.e. providing open access to research publications and sharing research data and open-source software and hardware – but also covers effecting cultural change in scientific processes to ensure that the production of knowledge is inclusive, sustainable and equitable.

What does CERN’s Open Science Office do?

The Open Science Office answers questions, provides guidance and connects the CERN community with experts and resources. It organises CERN open science governance meetings and plans to organise training courses and workshops in the future. It was created in 2023, following the release of CERN’s 2022 open science policy ,and will publish CERN’s first open science report in 2025.

Why is open science important to CERN?

We are lucky at CERN that our founding Convention gave us an early mandate for open science, and it has long been the norm within particle physics to share research results openly. With the digital transformation enabled by the World Wide Web (released by CERN in open source), CERN has pioneered a range of open science activities and services, making our Laboratory a world leader in open science. In recent years, government agencies and research funders from Member States and beyond have recognised the value of open science. This recognition is reflected in increased requirements to demonstrate open science practices when submitting funding applications.

How can I contribute to open science?

You are already doing so when you submit your preprints to CDS or arxiv, publish your research papers in open access in line with our open access policy, make your experimental data accessible at HEPdata or through the CERN Open Data Portal or produce open source software. By sharing your work under licenses that let others use it, study its source code, redistribute it and share improvements, you are helping to promote transparent and inclusive research practices at CERN and beyond.

How can the Open Science Office help me?

Contact the Open Science Office with any questions you might have. We offer guidance on open access publishing options for your papers, as well as advice on creating Data Management Plans (DMPs) to comply with funders’ requirements, and much more.

I want my software or hardware to be open source. How can the Open Science Office help?

The newly launched Open Source Programme Office serves the CERN community with answers and insights regarding open source issues.

How can I find out more about open science at CERN?

You can consult the CERN open science website, which includes details of upcoming events and training courses. You can also register for the Open Science Practitioners Forum e-group and join its regular meetings to have a say in CERN’s open science strategy.

For more questions, contact the CERN open science team at

ndinmore Wed, 07/10/2024 - 09:45 Publication Date Wed, 07/10/2024 - 09:43


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