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Toward axial channeling deployment at the Large Hadron Collider
No full textEfficient steering of particle beams in accelerators by means of bent crystals has been pursued over the last decades. Recent achievements in their operational deployment at CERN has resulted in a renewed interest in their exploitation for advanced accelerator and high energy physics concepts. Efforts to date have been focused on establishing planar channeling, given the intrinsic complexity of the process. However, the know-how developed with operation of bent crystals at the Large Hadron Collider has allowed this to be pushed a step further, demonstrating that axial channeling can also be used in the multi-TeV regime. Present results were achieved through a combination of mechanical crystal rotation and local orbit bump, proving that incorporating an additional degree of freedom in the design of future goniometers could enable the operational deployment of axial channeling, opening up the possibility for new and more efficient particle steering applications with bent crystals
Electroweak physics: experimental status
No full textElectroweak physics: current status and prospects from the experiment side - LHC tal
The ATLAS ITk Pixel and Strip Detector System for the Phase-II LHC Upgrade
No full textThe inner detector of the present ATLAS experiment has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the ATLAS Phase-II Upgrade, the particle densities and radiation levels will exceed current levels by a factor of ten. The instantaneous luminosity is expected to reach unprecedented values, resulting in up to 200 proton- proton interactions in a typical bunch crossing. The new detectors must be faster and they need to be more highly segmented. The sensors used also need to be far more resistant to radiation, and they require much greater power delivery to the front-end systems. At the same time, they cannot introduce excess material which could undetermine tracking performance. For those reasons, the inner tracker of the ATLAS detector was redesigned and will be rebuilt completely. The ATLAS Upgrade Inner Tracker (ITk) consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of silicon micro-strip sensors. The pixel detector has to deal with the challenging requirements in terms of radiation hardness, power dissipation and production yield. Several silicon pixel sensors technologies will be employed in the five barrel and endcap layers. As a timeline, it is facing to pre-production of components, sensor, building modules, mechanical structures and services. The pixel modules assembled with RD53B readout chips have been built to evaluate their production rate. A new powering scheme – serial – will be employed in the ITk pixel detector, helping to reduce the material budget of the detector as well as power dissipation. This talk will present the status of the ITk pixel project and lessons learned on the prototyping phase. The central part of the strip tracker (barrel) will be composed of rectangular short and long strip sensors. The forward regions of the strip tracker (end- caps) consist of six disks per side, with trapezoidal shaped sensors of various lengths and strip pitches. After the completion of final design reviews in key areas, such as sensors, modules, front-end electronics, and ASICs, a large scale prototyping program has been completed in all areas successfully. We present an overview of the strip system and highlight the final design choices of sensors, module designs and ASICs. We will summarize results achieved during prototyping and the current challenges of pre-production and production on various detector components, of the pixel and strip system with an emphasis on Quality Assurance and Quality Control procedures
The Cu conundrum remains unsolved
No full textNear the doubly-magic nucleus 78Ni (Z=28, N=50), there has been a decades-long debate on the existence of a long-lived isomer in 76Cu. A recent mass measurement claimed to have settled the debate, by measuring the energy of the isomer and shedding light on the structure of the nucleus. In this work, we present new, more accurate, and precise values of the half-lives of the isomeric and ground states in 76Cu. Our findings suggest that both states have very similar half-lives, in the 600–700 ms range, in disagreement with the literature values, implying that they cannot be differentiated by their decay curves. These results raise more questions than they answer, reopening the debate and showing that the structures in 76Cu are still not fully understood.Near the doubly-magic nucleus \nuc{Ni}{78} (, ), there has been a decades-long debate on the existence of a long-lived isomer in \nuc{Cu}{76}. A recent mass measurement claimed to have settled the debate, by measuring the energy of the isomer and shedding light on the structure of the nucleus. In this work, we present new, more accurate, and precise values of the half-lives of the isomeric and ground states in \nuc{Cu}{76}. Our findings suggest that both states have very similar half-lives, in the 600-700 ms range, in disagreement with the literature values, implying that they cannot be differentiated by their decay curves. These results raise more questions than they answer, reopening the debate and showing that the structures in \nuc{Cu}{76} are still not fully understood
ttH+tH measurements from ATLAS
No full textThe study of Higgs boson production in association with one or two top quarks provides a key window into the properties of the two heaviest fundamental particles in the Standard Model, and in particular into their couplings. This talk presents property measurement of Higgs boson, in particular cross section and CP nature, with tH and ttH production in pp collisions collected at 13 TeV with the ATLAS detector using the full Run 2 dataset of the LHC
Rapidity and multiplicity dependence of charged-particle flow in Pb collisions at Tev
No full textThe elliptic and triangular flow of charged particles are measured using two-particle angular correlations in Pb collisions in the pseudorapidity range 2.0 4.8. The data sample was collected by the LHCb experiment in 2016 at a centre-of-mass energy per nucleon pair of TeV, containing in total approximately 1.5 billion collision events. Non-flow contributions are obtained in low-multiplicity collisions and subtracted to extract the flow harmonics. The results are presented as a function of event multiplicity and hadron transverse momentum. Comparisons with a full (3+1)D dynamic model indicate that it overestimates the measured elliptic flow. A comparison between the forward and backward regions reveals no significant differences in flow parameters, suggesting that final-state effects may dominate over initial-state effects in the origin of flow in small systems.The elliptic and triangular flow of charged particles are measured using two-particle angular correlations in pPb collisions in the pseudorapidity range 2.0 < |η| < 4.8. The data sample was collected by the LHCb experiment in 2016 at a centre-of-mass energy per nucleon pair of TeV, containing in total approximately 1.5 billion collision events. Non-flow contributions are obtained in low-multiplicity collisions and subtracted to extract the flow harmonics. The results are presented as a function of event multiplicity and hadron transverse momentum. Comparisons with a full (3+1)D dynamic model indicate that it overestimates the measured elliptic flow. A comparison between the forward and backward regions reveals no significant differences in flow parameters, suggesting that final-state effects may dominate over initial-state effects in the origin of flow in small systems.[graphic not available: see fulltext]The elliptic and triangular flow of charged particles are measured using two-particle angular correlations in Pb collisions in the pseudorapidity range \cal{2.0 4.8}. The data sample was collected by the LHCb experiment in 2016 at a centre-of-mass energy per nucleon pair of TeV, containing in total approximately 1.5 billion collision events. Non-flow contributions are obtained in low-multiplicity collisions and subtracted to extract the flow harmonics. The results are presented as a function of event multiplicity and hadron transverse momentum. Comparisons with a full (3+1)D dynamic model indicate that it overestimates the measured elliptic flow. A comparison between the forward and backward regions reveals no significant differences in flow parameters, suggesting that final-state effects may dominate over initial-state effects in the origin of flow in small systems
Quench Modeling of the GaToroid Demonstrator Magnet for Hadron Therapy
No full textIn the design of superconducting magnets, ensuring thermal stability during operation is of paramount importance. This study aims to predict heat propagation and temperature distribution during a quench event in the Low Temperature Superconductor (LTS) demonstrator of the GaToroid coil. An efficient 1-D Finite Element Method (FEM) quench propagation model was employed, incorporating a thermal network model to account for heat interactions between turns in the transverse direction. The study highlights the relevance of accounting for the transverse propagation for an accurate description of the normal zone propagation. The predicted numerical results are validated against experimental data obtained during a dedicated test campaign
Study of discharges observed in the CMS GE1/1 station during LHC Run-3
No full textSince July 2022, GE1/1, the first station using Gas Electron Multiplier (GEM) technology in the Compact Muon Solenoid (CMS) experiment, has been participating in the data-taking in proton–proton (p–p) collisions. This station is the first of three (GE1/1, GE2/1 and ME0) planned to be installed in CMS, to cope with the challenging conditions given by the upgrade of luminosity of the Large Hadron Collider (High-Luminosity LHC program, or HL-LHC) (Colaleo et al., 2015) . This contribution illustrates in detail the analysis developed to monitor the discharge rate per each LHC fill and the strategies developed to operate the chambers safely. An important intervention was the modification of the High Voltage (HV) power system, to correctly power detectors affected by short circuits in the GEM foils. The contribution will also present the current status of operation for GE1/1 in Run-3 in 2023 and the next steps to be implemented to improve the behaviour of the detectors
Design and Characterization of a Radiation-Tolerant Wireless Physical Layer for Control Applications in CERN Particle Accelerators
No full textThe article explores the design and radiation characterization of a wireless physical layer (PHY) specifically tailored for equipment control in harsh radiation environments, such as those in particle accelerators like the large hadron collider
(LHC). The PHY, built with commercial-off-the-shelf (COTS), leverages a software-defined radio (SDR), which, compared to dedicated transceivers, provides more flexibility and enables enhanced reliability through mitigation techniques. It is designed for low latency to meet the sampling time requirements of current
LHC control applications. The PHY is developed to be radiation-tolerant, capable of withstanding the LHC radiation environment. The article presents the radiation characterization of all system components using a 200-MeV proton beam. Experimental results show the link’s robustness against total ionizing dose (TID) and single-event effects (SEEs), with no performance degradation due to SEEs and tolerance up to kGy of dose. Radiation-induced link losses were observed, and strategies to enhance link reliability were discussed