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Design and Performance of a 96-channel Resistive Micromegas Detector for ENUBET
No full textThe PICOSEC-Micromegas (PICOSEC-MM) detector is a fast gaseous detector that achieves picosecond-level timing by coupling a Cherenkov radiator, typically an MgF2 crystal, to a Micromegas-based photodetector with a photocathode. This configuration allows the fast photoelectron-induced signal to suppress the intrinsic time jitter of gaseous detectors, enabling sub-20 ps timing precision while preserving the robustness and scalability of micro-pattern gaseous detector technologies. The 96-pad PICOSEC-MM detector is a large-area demonstrator optimized for precision timing in high-energy physics, building on research and development insights from earlier 7-pad resistive prototypes to validate scalability, uniformity, and robustness for the ENUBET project. It employs a 2.5 nm diamond-like carbon photocathode and a Micromegas board with a surface resistivity of 10 megaohms per square, and was characterized using 150 GeV/c muons at the CERN SPS beamline, with one-third of the active area instrumented per run. A dedicated alignment procedure for multi-pad PICOSEC-MM systems was used to reconstruct pad centers and merge measurements across regions, yielding a timing resolution of 43 ps and uniform signal arrival time distributions over the tested area. Mechanical flatness was identified as a key factor, with planarity tolerances within 10 micrometers required to maintain good timing resolution, and the successful operation of the 96-pad demonstrator confirms the scalability of the PICOSEC-MM concept toward robust, high-granularity, picosecond-level gaseous timing detectors for monitored neutrino beam experiments such as ENUBET
Particle production and identification for the T10 secondary beamline of the CERN East Area
No full textThe particle composition of the T10 beam line in the renovated East Hall at CERN was measured using several methods: pressure scans on a threshold Cherenkov counter, a lead-glass calorimeter, time-of-flight, and finally using two separate threshold Cherenkov counters. For the pressure scans, at a given beam momentum, the count rate in the Cherenkov counters is measured as a function of pressure which allows computation of the fraction of a specific particle species. For the method using two threshold Cherenkov counters, one set above and one set below the threshold for the particle species to be identified, the difference relative to a beam trigger gives the relevant fraction. The measurement was proposed in the “Beamline For Schools” competition by team Particular Perspective and carried out in 2023. This data was expanded with pressure scans in 2023 and 2025. A comprehensive overview results of the particle content of the T10 beam.The particle composition of the T10 beam line in the renovated East Hall at CERN has been measured using several experimental techniques and detectors: pressure scans on a threshold Cherenkov counter, a lead-glass calorimeter, time-of-flight, and finally using two separate threshold Cherenkov counters. For the pressure scans, at a given beam momentum, the count rate in the Cherenkov counters is measured as a function of pressure in the counter. The count rate normalized to the rate of beam particles allows computation of the fraction of a specific particle type in the beam. For the method using two threshold Cherenkov counters, one set above and one set below the threshold for the particle species to be identified, with the difference relative to a beam trigger giving the particle fraction for that species. The measurement was proposed in the context of the ``Beamline For Schools'' competition by team Particular Perspective and carried out in 2023. This data was expanded with pressure scans in 2023 and 2025. Overlapping data is compared, leading to a comprehensive overview of the particle content of the T10 beam
ATLAS Event Display: Higgs boson decay to two muons
No full textCandidate Higgs boson event decaying to two muons, recorded by ATLAS in 2024 at 13.6 TeV
Search for associated production of a Higgs boson and of two vector bosons via vector boson scattering
No full textA search for the production of a Higgs boson in association with two vector bosons via vector boson scattering is presented. The search uses CMS data from proton-proton collisions at collected from 2016 to 2018, corresponding to an integrated luminosity of . Selected events are consistent with the presence of two jets originating from vector boson scattering and a Higgs boson decaying into a pair of b quarks, reconstructed as a single large-cone jet, while final states with 0, 1 or 2 charged leptons coming from the decays of the two vector bosons are studied. The study constrains the quartic coupling strength relative to the standard model, , in the observed (expected) range [0.40, 1.60] ([0.34, 1.66]) at confidence level when the other Higgs boson couplings are fixed to their SM values. The process is also sensitive to the and quartic couplings independently, whose strengths relative to the standard model are constrained in the observed (expected) ranges [0.17, 1.84] ([0.11, 1.89]) and [--0.37, 2.38] ([--0.54, 2.54]), for and respectively. A two-dimensional scan is performed to determine exclusion regions in the - plane
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