8 research outputs found

    First background-free limit from a directional dark matter experiment: results from a fully fiducialised DRIFT detector

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    The addition of O2 to gas mixtures in time projection chambers containing CS2 has recently been shown to produce multiple negative ions that travel at slightly different velocities. This allows a measurement of the absolute position of ionising events in the z (drift) direction. In this work, we apply the z-fiducialisation technique to a directional dark matter search. In particular, we present results from a 46.3 live-day source-free exposure of the DRIFT-IId detector run in this completely new mode. With full-volume fiducialisation, we have achieved the first background-free operation of a directional detector. The resulting exclusion curve for spin-dependent WIMP-proton interactions reaches 0.9 pb at 100 GeV/c2, a factor of 2 better than our previous work. We describe the automated analysis used here, and argue that detector upgrades, implemented after the acquisition of these data, will bring an additional factor of \u3e3 improvement in the near future

    Status of Muon Collider Research and Development and Future Plans

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    The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from a heavy-Z target and proceeding through the phase rotation and decay (πμνμ\pi \to \mu \nu_{\mu}) channel, muon cooling, acceleration, storage in a collider ring and the collider detector. We also present theoretical and experimental R & D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the R & D since the Feasibility Study of Muon Colliders presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A. Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics, Accelerators and Beam

    Search for a Light CP -odd Higgs Boson and Low-Mass Dark Matter at the Belle Experiment

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    View references (31) We report on the first Belle search for a light CP-odd Higgs boson, A0, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events produced via the dipion transition (2S)→ (1S)π+π-, followed by the on-shell process (1S)→γA0 with A0→χχ, or by the off-shell process (1S)→γχχ. Utilizing a data sample of 157.3×106 (2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges MA0<8.97 GeV/c2 and Mχ<4.44 GeV/c2. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5 GeV/c2

    Report of the Instrumentation Frontier Working Group for Snowmass 2021

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    Detector instrumentation is at the heart of scientific discoveries. Cutting edge technologies enable US particle physics to play a leading role worldwide. This report summarizes the current status of instrumentation for High Energy Physics (HEP), the challenges and needs of future experiments and indicates high priority research areas. The Snowmass Instrumentation Frontier studies detector technologies and Research and Development (R&D) needed for future experiments in collider physics, neutrino physics, rare and precision physics and at the cosmic frontier. It is divided into more or less diagonal areas with some overlap among a few of them. We lay out five high-level key messages that are geared towards ensuring the health and competitiveness of the US detector instrumentation community, and thus the entire particle physics landscape

    Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

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    We report on a measurement of the Ωc0\Omega_c^0 lifetime using Ωc0Ωπ+\Omega_c^0 \to \Omega^-\pi^+ decays reconstructed in e+eccˉe^+e^-\to c\bar{c} data collected by the Belle II experiment and corresponding to 207 fb1207~{\rm fb^{-1}} of integrated luminosity. The result, τ(Ωc0)=243±48(stat)±11(syst) fs\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs, agrees with recent measurements indicating that the Ωc0\Omega_c^0 is not the shortest-lived weakly decaying charmed baryon

    Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

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    We report on a measurement of the Ωc0\Omega_c^0 lifetime using Ωc0Ωπ+\Omega_c^0 \to \Omega^-\pi^+ decays reconstructed in e+eccˉe^+e^-\to c\bar{c} data collected by the Belle II experiment and corresponding to 207 fb1207~{\rm fb^{-1}} of integrated luminosity. The result, τ(Ωc0)=243±48(stat)±11(syst) fs\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs, agrees with recent measurements indicating that the Ωc0\Omega_c^0 is not the shortest-lived weakly decaying charmed baryon

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

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    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field
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