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Accessing the deuteron source with pion–deuteron femtoscopy in Pb–Pb collisions at TeV
No full textFemtoscopy of non-identical particle pairs has been instrumental for precision measurements of both two-particle sources and the final-state interactions in high-energy elementary and heavy-ion collisions. The majority of measurements assessing the source properties are based on identical particle pairs, providing direct access to the characteristics of the single-particle source. The work in this paper demonstrates, via femtoscopy measurements of charged pion–deuteron pairs in Pb–Pb collisions at TeV, the feasibility of accessing the characteristics of the single-particle femtoscopic source by using particle pairs with large mass differences such as pions and deuterons. The first experimental results of the measurement of deuteron source sizes in ultrarelativistic heavy-ion collisions are presented. The results show good agreement with the trend derived from other charged hadrons such as pions, kaons, and protons as a function of transverse mass, indicating similar source properties.Femtoscopy of non-identical particle pairs has been instrumental for precision measurements of both two-particle sources and the final-state interactions in high-energy elementary and heavy-ion collisions. The majority of measurements assessing the source properties are based on identical particle pairs, providing direct access to the characteristics of the single-particle source. The work in this paper demonstrates, via femtoscopy measurements of charged pion-deuteron pairs in Pb-Pb collisions at TeV, the feasibility of accessing the characteristics of the single-particle femtoscopic source by using particle pairs with large mass differences such as pions and deuterons. The first experimental results of the measurement of deuteron source sizes in ultrarelativistic heavy-ion collisions are presented. The results show good agreement with the trend derived from other charged hadrons such as pions, kaons, and protons as a function of transverse mass, indicating similar source propertie
Search for -channel scalar and vector leptoquark exchange in the high-mass dimuon and dielectron spectra in proton-proton collisions at 13 TeV
No full textA search for -channel exchange of leptoquarks (LQs) is performed in dimuon and dielectron spectra using proton-proton collision data collected at 13 TeV with the CMS detector at the CERN LHC. The data correspond to an integrated luminosity of 138 fb. Eight scenarios are considered, in which scalar or vector LQs couple up or down quarks to muons or electrons, for dilepton invariant masses above 500 GeV. The LQ masses are probed up to 5 TeV, beyond a regime probed by previous pair-production and single-production searches. The differential distributions of dilepton events are fit to templates that model the nonresonant LQ exchange and various standard model background processes. Limits are set on LQ-fermion coupling strengths for scalar and vector LQ masses in the 1-5 TeV range at 95% confidence level, establishing stringent limits on first- and second-generation LQs.A search for -channel exchange of leptoquarks (LQs) is performed in dimuon and dielectron spectra using proton-proton collision data collected at = 13 TeV with the CMS detector at the CERN LHC. The data correspond to an integrated luminosity of 138 fb. Eight scenarios are considered, in which scalar or vector LQs couple up or down quarks to muons or electrons, for dilepton invariant masses above 500 GeV. The LQ masses are probed up to 5 TeV, beyond a regime probed by previous pair-production and single-production searches. The differential distributions of dilepton events are fit to templates that model the nonresonant LQ exchange and various standard model background processes. Limits are set on LQ-fermion coupling strengths for scalar and vector LQ masses in the 1-5 TeV range at 95% confidence level, establishing stringent limits on first- and second-generation LQs
Inverted CERN School of Computing 2025
No full textAs quantum computers advance, they pose a significant threat to our current cryptographic infrastructure, particularly RSA encryption. This presentation will explore how RSA can be broken using Shor's algorithm and examine the landscape of post-quantum encryption algorithms.
## Presentation Overview
### Introduction to RSA and Its Importance in Modern Cryptography
- Brief history of RSA
- Current widespread use in secure online transactions and communications
### The Quantum Threat: Shor's Algorithm and Its Impact on RSA
- Explanation of Shor's algorithm
- How quantum computers can factor large numbers exponentially faster than classical computers
- Implications for RSA security
### Post-Quantum Cryptography: An Overview
- Introduction to post-quantum cryptographic algorithms
- Types of post-quantum cryptography (lattice-based, code-based, multivariate polynomial, hash-based signatures)
### Standardization Efforts: NIST's Post-Quantum Cryptography Project
- Overview of NIST's standardization process
- Selected algorithms (CRYSTALS-Dilithium, FALCON, SPHINCS+, CRYSTALS-Kyber)
- Challenges in standardization and implementation
### Implementation Considerations for Post-Quantum Algorithms
- Integration into existing cryptographic libraries
- Performance comparisons with classical algorithms
- Security analysis and known vulnerabilities
## Key Takeaways
1. Understanding of the quantum threat to RSA and current public-key cryptography
2. Knowledge of post-quantum cryptographic algorithms and their types
3. Insights into implementation challenges and migration strategies
4. Insights into preparing for the post-quantum era in cybersecurit
Inverted CERN School of Computing 2025
No full textPermutation equivariant and Lorentz invariant neural networks have garnered the attention of the ML community at large for a while now, finding particular success in cases where symmetries in the data space can be exploited to overcome issues of low statistics and constraints on training time or model size. In high energy physics, however, neither problem is common to us: due to the inherent probabilistic nature of our experiments, we can simulate datasets that would excite even the most ingrained OpenAI engineer, and our computational power is on a vastly different scale compared to the average ML enthusiast.
The main strength of equivariant networks in our field lies in a different aspect, in fact, one of the main aspects that had the HEP community hesitant to adopt ML solutions in the first place, namely that of explainability. Compared to other approaches that use non-specialized architectures with many parameters and high flexibility but don’t take into account underlying physics principles, equivariant networks provide reduced complexity and increased interpretability—two key factors when searching for new physics phenomena in underexplored parameter spaces.
This talk will introduce the audience to the concepts and benefits of equivariant methods in ML. After a brief motivation for this subfield, accompanied by a short maths lesson, the audience will be introduced to the core concepts of equivariant networks, followed by examples of architectures and applications. The hour will conclude with a discussion of the newest developments in this and related fields, perhaps with a brief look at applications outside of physics
European Strategy for Particle Physics 2026: Frontier sensor R&D for the ALICE 3 apparatus
No full textThe ALICE Collaboration plans to build a new experimental setup, ALICE 3, which will be installed during Long Shutdown 4. This apparatus will maximize the potential of the HL-LHC as a heavy-ion collider by giving access to new and unexplored experimental observables, thereby enabling the investigation of open fundamental questions regarding the quark-gluon plasma and other aspects of the strong interaction. The hallmarks of the ALICE 3 physics programme are discussed in a dedicated ESPP input document. They require unprecedented pointing resolution (e.g., about 10 m at MeV/), large acceptance ( MeV/) and extensive identification capabilities for electrons, hadrons and muons. The setup consists of a compact silicon pixel tracker within a new superconducting magnet (2 T), silicon time-of-flight layers, a ring-imaging Cherenkov detector, a muon identification system, an electromagnetic calorimeter, a forward photon conversion tracker, and two forward counting detectors. An intense R&D programme on frontier sensors is well underway. The primary focus of the R&D on Monolithic Active Pixel Sensors for the trackers is on high spatial precision, low material budget, low power consumption, and large-area sensors. A pioneering concept is being pursued for a retractable barrel vertex detector that closes to a minimum radius of 5 mm from the interaction point. For particle identification, R&D is in progress towards ultra-fast timing with silicon sensors for time-of-flight measurement, and towards improving the radiation hardness of silicon photo-multipliers. The target specifications of the ALICE 3 silicon sensors are similar to those of detectors at future colliders. The advancements in sensor technologies targeted by the ALICE 3 R&D programme constitute a significant milestone in the ECFA strategic roadmap for detector R&D
Luminosity measurement using Timepix3 during 2018 pp collisions at √s=13 TeV in the ATLAS experiment
No full textPrecise luminosity determination is of paramount importance for the ATLAS physics program, given its often direct impact on the uncertainties of cross-section measurements. A set of complementary luminometers is crucial in this context to ensure high stability and precision of the ATLAS luminosity measurement. In 2018, two Timepix3 detector setups, consisting of 4 Timepix3 assemblies, synchronized with the LHC orbit clock, were installed in the ATLAS experiment to study their capabilities of measuring luminosity. The detectors benefit from a fine segmentation and a narrow per-pixel time resolution allowing for a high-quality track reconstruction and particle identification. One of the Timepix3 sensors was equipped with a 6LiF neutron converter, allowing also for the discovery of neutral radiation. The installed system was used to study luminosity in different time frames: long term (run-by-run), short term (within a single run) and instantaneous (for each bunch crossing). For the long- and short-term luminosity, two partly independent algorithms: cluster counting, and thermal neutron counting, are proposed. In this presentation, we discuss the methodology to use Timepix3 sensors for luminosity measurement and show first performance, based on data from pp-collisions at √s=13 TeV, recorded in 2018. This includes a discussion of the subtraction of the count rate related to the activation of the structures surrounding the detectors and studies showing that the Timepix3 luminosity measurement exhibits good linearity with respect to the pile-up parameter μ. We demonstrate that different algorithms provide different signal-to-background ratios and indicate the potential to use Timepix3 in the ongoing third running period of the LHC for luminosity measurement with the ATLAS experiment
Zgamma cross section measurement at 13.6 TeV
No full textA measurement of the production cross section in proton-proton collisions at a center-of-mass energy of 13.6 TeV using the leptonic final states is presented. A data set corresponding to an integrated luminosity of 34.8 fb, collected by the CMS experiment at the LHC in 2022 is used. Events with an oppositely charged pair of muons or electrons together with an isolated photon are selected. The measured fiducial cross section for the combined muon and electron channels is pb
CERN Tape Archive Workshop : CTA 2025
No full textTape reading efficiency, defined as the ratio between the effective average data reading rate and the maximal data reading rate, is reduced by two operations the tape drive inevitably needs to do and during which it can not read any data. The first is mounting the tape containing the file into the drive, after possibly having unmounted the tape that was in it before. The second is spooling the tape to the position of the file to be read. In this presentation we will explore which factors determine this reading efficiency loss and what could be done to mitigate it. We will in particular look at collocation, i.e. the strategy of writing files that are likely to be recalled together without interleaving them with unrelated files. To validate our hypotheses we analysed one month (Feb 2025) of ATLAS tape recall activity totalling about 6 PB of data contained in 1.6 million files spread over 1800 datasets
CERN Tape Archive Workshop : CTA 2025
No full textThe Tapeguy is TRIUMF's home build tape system for ATLAS T1 data center, It was designed to be a stable system that can reliably store and retrieve LHC produced data as a tiered HSM system. we also open to other solutions, evaluated CERN CTA at site in 2024. the talk will present current tapeguy status, recent updates, and the evaluation done at site
