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Long-Term Ageing Studies on Eco-Friendly Resistive Plate Chamber Detectors
No full textIn high-energy physics, resistive plate chamber (RPC) detectors operating in avalanche mode make use of a high-performance gas mixture. Its main component, Tetrafluoroethane (CHF), is classified as a fluorinated greenhouse gas. The RPC EcoGas@GIF++ collaboration is pursuing an intensive R&D; on new gas mixtures for RPCs to explore eco-friendly alternatives complying with recent European regulations. The performance of different RPC detectors has been evaluated at the CERN Gamma Irradiation Facility with Tetrafluoropropene (CHF)-CO-based gas mixtures. A long-term ageing test campaign was launched in 2022, and since 2023, systematic long-term performance studies have been carried out thanks to dedicated beam tests. The results of these studies are discussed together with their future perspectives.In high-energy physics, resistive plate chamber (RPC) detectors operating in avalanche mode make use of a high-performance gas mixture. Its main component, Tetrafluoroethane (C2H2F4), is classified as a fluorinated greenhouse gas. The RPC EcoGas@GIF++ collaboration is pursuing an intensive R&D on new gas mixtures for RPCs to explore eco-friendly alternatives complying with recent European regulations. The performance of different RPC detectors has been evaluated at the CERN Gamma Irradiation Facility with Tetrafluoropropene (C3H2F4)-CO2-based gas mixtures. A long-term ageing test campaign was launched in 2022, and since 2023, systematic long-term performance studies have been carried out thanks to dedicated beam tests. The results of these studies are discussed together with their future perspectives
A system solution for a 100 kA class high temperature superconducting line for HL-LHC and for wider energy applications
No full textThe powering of the High Luminosity magnets of the Large Hadron Collider relies on Cold Powering Systems incorporating direct current superconducting lines, called Superconducting Links, based on magnesium diboride cables. A Cold Powering System interconnects the magnets in the accelerator existing tunnel to the power converters in newly excavated galleries that are about 8 m higher than the accelerator tunnel and up to about 100 m distant from the magnets. It feeds circuits rated at different currents and is designed to transfer a total current of up to |117| kA with magnesium diboride and Rare-Earth-Barium-Copper-Oxide technologies. After about ten years of development, the first Cold Powering System was successfully constructed and tested at CERN. The Superconducting Link was measured in a geometrical configuration that included a vertical path simulating the final routing in the accelerator underground. The test campaign validated the mechanical, cryogenic and electrical performance of the system both in steady state conditions and under various transient scenarios. This paper reports on the results of the tests and details the performance of the first ever built magnesium diboride and Rare-Earth-Barium-Copper-Oxide 100 kA class superconducting system
Lepton Flavour Universality Tests Using Semileptonic b-Hadron Decays at the LHCb Detector
No full textThis review highlights advancements in testing Lepton Flavour Universality (LFU) through semileptonic b-hadron decays at the LHCb detector. Measurements of the LFU and provide evidence of deviations from Standard Model (SM) predictions, suggesting the presence of possible New Physics (NP). However, the longitudinal polarisation results are in good agreement with SM expectations, placing constraints on potential NP theories, such as the leptoquarks or charged Higgs models. Further improvements in the measurements’ precision are expected with the new data from LHCb Run 3, collected with higher instantaneous luminosity and improved trigger
Development of the ATLAS Liquid Argon Calorimeter On-detector Readout Electronics for the HL-LHC
No full textThe High-Luminosity LHC will start operations for physics around 2030, allowing to collect ten times more data than what will have been achieved by the LHC. This expansion of the dataset will be achieved by increasing the number of collisions per bunch crossing, leading, however, to higher radiation doses and busier events. To cope with those harsher data taking conditions and to be compatible with the new ATLAS data acquisition paradigm, the ATLAS Liquid Argon Calorimeter on-detector electronics will have to be replaced. The two main elements, the Front-End readout Board and the Calibration Board, had to be fully redesigned and rebuilt. The Front-End board will amplify, shape and digitize the calorimeter ionisation signal at 40 MHz and on two gains over a 16-bit dynamic range with 11 bit precision. Custom Preamplifier/Shaper and ADC ASICs have been designed to meet the stringent requirement in terms of linearity and radiation hardness. The Calibration board will inject a calibration signal into the detector with a non-linearity of one permille and non-uniformity between channels of 0.25% with a pulse rise time smaller than 1 ns, facilitated by two additional custom-designed ASICs: The LADOC, a high frequency pulser and the CLADOC, which is the DAC part. Mass ASIC testing procedures are being established while, in parallel, full prototype boards are being assembled and tested.The poster will cover the validation of the performance of those boards, a critical step before launching the full production of about 1500 boards and their installation which is planned to start in 202
Dissecting Jet Modification in the QGP with Multi-Point Energy Correlators
No full textEnergy correlators have recently attracted significant attention in the study of heavy ion collisions due to their potential to robustly connect experimental measurements with an underlying quantum field theoretic description. While theoretical studies have so far primarily focused on the simplest two-point correlator, mapping out the dynamics of the quark-gluon plasma (QGP) will require developing a theoretical understanding of multi-point energy correlators. In this paper we present a systematic theoretical study of multi-point energy correlators for jets fragmenting in a dense quark-gluon plasma, accounting for both the medium's perturbative modification to the jet, and its hydrodynamical back-reaction. We consider both the scaling behavior of projected correlators, as well as the shape dependent three-point correlator, highlighting how both provide insight into interactions with the QGP. We discuss the parametric dependence of modifications on the medium scales, opening new opportunities to experimentally separate jet modifications from the medium response. Our results open the door to a systematic exploration of multi-point energy correlators in heavy ion collisions
Super-Higher-Form Symmetries
No full textWe generalize the study of higher-form-symmetries to theories with supersymmetry. Using a supergeometry formulation, we find that ordinary higher-form-symmetries nicely combine with supersymmetry to give rise to a much larger spectrum of topological conserved (super)currents. These can be classified as a supersymmetric version of Chern-Weil symmetries, and a brand new set of geometric-Chern-Weil symmetries whose generators are constructed using invariant differential forms in supermanifolds. For N=1 super-Maxwell theory in various dimensions, we build the topological operators generating these super-higher-form symmetries and construct defects carrying non-trivial charges. Notably, the charge is proportional to the super-linking number between the super-hypersurface supporting the symmetry generator and the one supporting the defect.We generalize the study of higher-form-symmetries to theories with supersymmetry. Using a supergeometry formulation, we find that ordinary higher-form-symmetries nicely combine with supersymmetry to give rise to a much larger spectrum of topological conserved (super)currents. These can be classified as a supersymmetric version of Chern-Weil symmetries, and a brand new set of geometric-Chern-Weil symmetries whose generators are constructed using invariant differential forms in super-manifolds. For N=1 super-Maxwell theory in various dimensions, we build the topological operators generating these super-higher-form symmetries and construct defects carrying non-trivial charges. Notably, the charge is proportional to the super-linking number between the super-hypersurface supporting the symmetry generator and the one supporting the defect
ML-based muon identification using a FNAL-NICADD scintillator chamber for the MID subsystem of ALICE 3
No full textThe ALICE Collaboration is planning to construct a newdetector (ALICE 3) aiming at exploiting the potential of thehigh-luminosity Large Hadron Collider (LHC). The new detector willallow ALICE to participate in LHC Run 5 scheduled from 2036 to2041. The muon-identifier subsystem (MID) is part of the ALICE 3reference detector layout. The MID will consist of a standardmagnetic iron absorber (≈4 nuclear interaction lengths)followed by muon chambers. The baseline option for the MID chambersconsiders plastic scintillation bars equipped with wave-lengthshifting fibers and readout with silicon photomultipliers. Thispaper reports on the performance of a MID chamber prototype using3 GeV/c pion- and muon-enriched beams delivered by the CERNProton Synchrotron (PS). The prototype was built using extrudedplastic scintillator produced by FNAL-NICADD (Fermi NationalAccelerator Laboratory - Northern Illinois Center for Acceleratorand Detector Development). The prototype was experimentallyevaluated using varying absorber thicknesses (60, 70, 80, 90, and100 cm) to assess its performance. The analysis was performed usingMachine Learning techniques and the performance was validated withGEANT 4 simulations. Potential improvements in both hardware anddata analysis are discussed.The ALICE Collaboration is planning to construct a new detector (ALICE 3) aiming at exploiting the potential of the high-luminosity Large Hadron Collider (LHC). The new detector will allow ALICE to participate in LHC Run 5 scheduled from 2036 to 2041. The muon-identifier subsystem (MID) is part of the ALICE 3 reference detector layout. The MID will consist of a standard magnetic iron absorber ( nuclear interaction lengths) followed by muon chambers. The baseline option for the MID chambers considers plastic scintillation bars equipped with wave-length shifting fibers and readout with silicon photomultipliers. This paper reports on the performance of a MID chamber prototype using 3 GeV/ pion- and muon-enriched beams delivered by the CERN Proton Synchrotron (PS). The prototype was built using extruded plastic scintillator produced by FNAL-NICADD (Fermi National Accelerator Laboratory - Northern Illinois Center for Accelerator and Detector Development). The prototype was experimentally evaluated using varying absorber thicknesses (60, 70, 80, 90, and 100 cm) to assess its performance. The analysis was performed using Machine Learning techniques and the performance was validated with GEANT 4 simulations. Potential improvements in both hardware and data analysis are discussed
Display of a H → γγ candidate event seen in the CMS detector
No full textDisplay of an event seen in the CMS detector in 2017 consistent with the production of a Higgs boson, which decays into a pair of photons, as part of a search for anomalous couplings