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ATLAS SMP+TOP summary
No full textOverview of the latest results on Effectove Field Theory interpretations from the ATLAS Collaboration in 2025. Overall the results eight analyses in the Standard Model electroweak sector and top quark sector are presented
Topical issue on the intersection of low-energy nuclear structure and high-energy nuclear collisions
No full textHigh-energy heavy-ion physics and low-energy nuclear structure physics have historically been disconnected fields. The hydrodynamic description of the quark-gluon plasma (QGP) requires input from nuclear structure to model the initial states of the colliding nuclei. Advances in both theory and experiment now show that the hydrodynamic evolution of the QGP is sensitive to the detailed features of the colliding nuclei, with remarkable consequences for experimental observables. The topical collection represents a joint effort between the low- and high-energy nuclear communities, reflecting the growing recognition that precision modeling of nuclear structure is essential for interpreting high-energy collision data. This new experimental approach opens outstanding opportunities to deepen our understanding of strong-interaction matter. Indeed, by probing many-body correlations of nucleons directly in the nuclear ground state, high-energy collisions provide a unique way to "image" nuclei, fully complementary to the techniques of low-energy experiments, where nuclear collectivity is usually inferred from spectroscopic information on excited states. Do emergent many-body QCD phenomena in nuclei manifest consistently across experiments and energy scales? Addressing this question requires synergy between collider data and state-of-the-art nuclear structure calculations. In view of the rapid progress of ab initio methods based on low-energy effective field theories of QCD, the implications are far-reaching: heavy-ion collisions can probe nuclear forces, while nuclear structure insights refine our understanding of QGP dynamics
Vibration Study of the Laser Transfer Line Structure for The Gamma Factory Proof of Principle Experiment
No full textThe Gamma Factory at CERN is a developing experiment aiming to generate high-intensity gamma-ray beams through the interaction of laser pulses with ultra-relativistic ion beams. A key technical challenge is ensuring the mechanical stability of the laser transport system. Vibrations in the CERN accelerator tunnels can disturb laser alignment, reducing performance and preventing efficient gamma-ray production. This project addresses that challenge by studying the vibrational behavior of the periscope support pillar, a structure responsible for guiding the laser into the accelerator, using interferometric techniques capable of detecting motion at the nanometer scale. The work began with the design of a Fabry–Perot interferometer, chosen for its high sensitivity. However, its extreme sensitivity made it impractical to align and operate in a noisy environment. To overcome this limitation, a Michelson interferometer was developed instead, providing a balance between robustness and resolution. With this setup, vibrations were measured under free-running, shock, and impact conditions, allowing both environmental noise and intrinsic resonances of the pillar to be identified. The results reveal characteristic vibrational modes and confirm the pillar’s role in suppressing facility-generated noise, providing essential data for stabilizing the enhancement cavity in the upcoming proof-of-principle experiment
ALICE Collaboration
No full textALICE Group Photo during the ALICE Week collaboration meeting at CERN in December 2025 (https://indico.cern.ch/event/1596309/
Modular sensor supports for precision alignment of HL-LHC components
No full textThe High Luminosity Large Hadron Collider (HL-LHC) is an ambitious upgrade project to increase the LHC collision rate, significantly enhancing the physics discovery potential of the present LHC beyond 2030. As part of this effort, new components must be aligned within an elliptical 1 tolerance envelope, with radii of 0.17 mm vertically and 0.33 mm radially over 420 m around the two high luminosity experiments ATLAS and CMS. To meet these stringent requirements, all components will be equipped with micro-metric alignment sensors, including 276 Wire Positioning Sensors and 148 Hydrostatic Levelling Sensors. These sensors must be rigidly attached to the component structures and accurately pre-adjusted relative to external reference networks. These requirements led CERN’s geodetic metrology group to develop a modular support system. This system ensures an ergonomic adjustment of sensors, a long-term positional stability, and a robustness against mechanical constraints. This paper presents the design approach and the results of the final testing and validation of the modular sensor support solution
Identification of low-energy kaons in the ProtoDUNE-SP detector
No full textThe Deep Underground Neutrino Experiment (DUNE) is a next-generation neutrino experiment with a rich physics program that includes searches for the hypothetical phenomenon of proton decay. Utilizing liquid-argon time-projection chamber technology, DUNE is expected to achieve world-leading sensitivity in the proton decay channels that involve charged kaons in their final states. The first DUNE demonstrator, ProtoDUNE Single-Phase, was a 0.77 kt detector that operated from 2018 to 2020 at the CERN Neutrino Platform, exposed to a mixed hadron and electron test-beam with momenta ranging from 0.3 to 7 GeV/c. We present a selection of low-energy kaons among the secondary particles produced in hadronic reactions, using data from the 6 and 7 GeV/c beam runs. The selection efficiency is 1% and the sample purity 92%. The initial energies of the selected kaon candidates encompass the expected energy range of kaons originating from proton decay events in DUNE (below 200 MeV). In addition, we demonstrate the capability of this detector technology to discriminate between kaons and other particles such as protons and muons, and provide a comprehensive description of their energy loss in liquid argon, which shows good agreement with the simulation. These results pave the way for future proton decay searches at DUNE
Facilitating Scientific Reproducibility and Interoperability through CWL Integration in the Dirac Grid Middleware
No full textIn the wake of the reproducibility crisis that has underscored the critical need for verifiable scientific research, the integration of Common Workflow Language (CWL) into the Dirac grid middleware represents a significant leap forward. CWL facilitates the precise definition of computational workflows, ensuring that they are easily shareable and executable across diverse computational environments. This standardization allows scientific processes to be replicated without ambiguity. Its widespread adoption across major workload and workflow management systems emphasizes its effectiveness. Dirac, a comprehensive framework for managing computational tasks and workflows at different scales, serving a broad range of communities from diverse scientific fields, has traditionally utilized specialized descriptive languages, introducing complexity and barriers to interoperability and seamless workflow reproduction. By adopting CWL, this study aims to eliminate these barriers, standardizing the description of computational tasks and thereby enhancing their reproducibility and interoperability. By streamlining the interface for defining computational tasks within Dirac, we enable researchers to effortlessly transition workflows from local to grid-scale environments and foster compatibility with a broader ecosystem of scientific tools. This integration promises not only to mitigate the challenges posed by the reproducibility crisis but also to significantly lower the threshold for engaging with complex computational infrastructures, thus accelerating scientific discovery and innovation across multiple disciplines
The neXt Dirac incarnation
No full textThe DIRAC interware has long served as a vital resource for user communities seeking access to distributed computing resources. Originating within the LHCb collaboration around 2000, DIRAC has undergone significant evolution. Despite its efficacy in meeting experiment-specific requirements, DIRAC has accrued technical debt over its 15-year history. Installation management remains intricate, with significant entry barriers and a reliance on bespoke infrastructure. The software development process lacks alignment with contemporary standards, impeding the onboarding process for new developers. Notably, integral components such as the network protocol and authentication mechanisms are proprietary and pose challenges for seamless integration with external applications. In response to these challenges, the DIRAC consortium has embarked on the development of DiracX. DiracX heralds a new era in distributed computing solutions. This contribution describes technical decisions, roadmap and timelines for the development of DiracX, while recognizing the criticality of maintaining a continuously operational DIRAC system for numerous user communities