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Physical Properties of Materials and Testing Methods
No full textThe use of materials in particle accelerator applications implies the consideration of physical properties in different environments than usual industrial applications. Cryogenic temperatures, high radiation, medium to high vacuum and high magnetic fields are requirements for which the behavior of materials has to be evaluated. In this lecture, Thermal, Electrical and Magnetic properties are briefly introduced, highlighting the mechanisms governing variation with temperature and magnetic field. Standards and testing methods for different properties are described, illustrated with practical examples. With regard to the characterization of thermal properties of a material, testing methods of heat capacity and thermal conductivity are described, with details of the main working principle and measurement examples. Determination of electrical resistivity and the residual resistivity ratio (RRR) are the main characteristics of electrical properties, together with specific characterization of superconducting materials. Testing magnetic properties deserve special attention; different methods are commonly employed to characterize non-magnetic and magnetic materials. In magnetic metals and ferrites non-linear behavior and hysteresis effects need to be considered in order to assess their suitability for applications or to model material performance
ATLAS and CMS HH/SH resonant searches in the 2b2τ final state
No full textThis talk is an overview of the latest ATLAS results in the search for resonant di-Higgs to bbtautau, together with the latest public CMS result, which involves an additional scalar
CMS track reconstruction performance during Run 3
No full textThe precise reconstruction of charged particle tracks is crucial for the overall performance of the CMS experiment. In this contribution, performance measurements of the track reconstruction both in simulation and data are presented, from the collisions that occurred during the last periods of the Run 3 of data taking at the LHC. A particular focus is given to the role and performance of the Silicon Pixel detector. Together with comparisons between data and simulation on important track quantities, the efficiencies measured at high level trigger and with the tag-and-probe techniques are discussed
HL-LHC Cost & Schedule Review 2025 - visits
No full textPhotos from the visits as part of the HL-LHC CSR25 to the HL-LHC underground galleries at Point 1, IT String and beam screen facility
BDF/SHiP Annual Report 2025
No full textThe report covers the progress of the SHiP collaboration and the HI-ECN3 Project Team since the start of the TDR phase mid-2024
Upgrade of ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC
No full textThe Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The High-Luminosity phase of LHC, delivering five times the LHC nominal instantaneous luminosity, is expected to begin in 2029. TileCal will require new electronics to meet the requirements of a 1 MHz trigger, higher ambient radiation, and to ensure better performance under high pile-up conditions. Both the on- and off-detector TileCal electronics will be replaced during the shutdown of 2026-2028. PMT signals from every TileCal cell will be digitized and sent directly to the back-end electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. The modular front-end electronics feature radiation-tolerant commercial off-the-shelf components and redundant design to minimise single points of failure. The timing, control and communication interface with the off-detector electronics is implemented with modern Field Programmable Gate Arrays (FPGAs) and high speed fibre optic links running up to 9.6 Gb/s. The TileCal upgrade program has included extensive R&D and test beam studies
QCD String Axions and -theory
No full textIn Yang-Mills theory without matter, there exist stable long electric fluxtube strings which carry a 1-form symmetry charge. Over the past decade or so, there has been increasing evidence from lattice calculations that the worldsheet theories of such QCD strings contain a massive pseudoscalar (axion), at least when . This has so far been puzzling from the perspective of holographic realizations of strings in confining gauge theories. In this note, we will show how such axions appear naturally in the realization of 4D Super-Yang-Mills (SYM) from -theory spacetimes in which the extra dimensions are modeled by certain complete metrics of -holonomy. This picture predicts that QCD string axions exist only if the gauge group is , , or (or a quotient/double-cover thereof), and is absent from the spectrum of stable QCD strings if the gauge group is , , , , or . We argue why we expect this pattern to persist for non-supersymmetric Yang-Mills strings, at least for large , something which could be tested in future lattice studies of QCD strings for gauge algebras of B, C, D, and E-type
Recent top-quark mass measurements from cross section from ATLAS
No full textHIghlights of recent top-quark mass extractions from ATLAS measurements of ttbar cross sections
