74 research outputs found

    The Global Network of Cavities to Search for Gravitational Waves (GravNet): A novel scheme to hunt gravitational waves signatures from the early universe

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    The idea of searching for gravitational waves using cavities in strong magnetic fields has recently received significant attention. Specifically, discussions focus on cavities with relatively small volumes, which are currently employed in the search for axions. In this context, we propose a novel experimental scheme that enables the detection of gravitational waves in the GHz regime, which could originate, for example, from primordial black hole mergers. The scheme is based on synchronous measurements of cavity signals from multiple devices operating in magnetic fields at distant locations. While gravitational wave signatures might be detectable in individual cavities, distinguishing them from noise is highly challenging. By analyzing the correlation among signals from several, possibly geographically separated cavities, it is not only possible to significantly enhance the signal-to-noise ratio but also to investigate the source of those gravitational wave signatures. In the context of this proposal, a first demonstration experiment with one superconducting cavity is currently conducted, which is the basis of the proposed data-analysis approaches. On this basis the prospects of GravNet (Global Network of Cavities to Search for Gravitational Waves) are outlined in the paper.Comment: 9 page

    Searching for Gravitational Waves with CMS

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    The idea of searching for gravitational waves using cavities in strong magnetic fields has recently received significant attention. Most concepts foresee moderate magnetic fields in rather small volumes, similar to those which are currently employed for axion-like particle searches. We propose to use the magnet system of the Compact Muon Solenoid (CMS) experiment after the high luminosity phase of the LHC as a key component for a future detector for gravitational waves in the MHz frequency range. In this paper we briefly discuss a possible cavity concept which can be integrated into CMS and additionally provide a first estimation of its possible sensitivity.Comment: 4 pages, 2 figure

    First results of the SUPAX Experiment: Probing Dark Photons

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    We show the first results of a new cavity based haloscope searching for dark photons with masses around 34¬†őľeV34~\mu\text{eV}. Dark photons are hypothetical vector particles and a compelling dark matter candidate. Having the same quantum numbers as photons a kinematic mixing between both is expected, leading to conversions from dark photons to standard model photons, where the photon frequency depends on the dark photon mass. For wavelengths in the microwave regime resonators are typically used to enhance the signal. A new experiment is setup at the University of Mainz. In this paper we present the initial results from the new setup searching for dark photons utilising a 8.3 GHz copper cavity at LHe temperatures. Limits on the kinetic mixing parameter Ōá<(6.20¬Ī3.15(exp.)¬Ī9.65(SG))‚čÖ10‚ąí14\chi < (6.20 \pm 3.15^\text{(exp.)} \pm 9.65^\text{(SG)}) \cdot 10^{-14} at 95\% CL are set at a single frequency as proof of concept. Finally the next steps of the experiment and expected sensitivity are detailed.Comment: 6 page

    The two-photon decay of X(6900) from light-by-light scattering at the LHC

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    The LHCb Collaboration has recently discovered a structure around 6.9 GeV in the double-J/ŌąJ/\psi mass distribution, possibly a first fully-charmed tetraquark state X(6900)X(6900). Based on vector-meson dominance (VMD) such a state should have a significant branching ratio for decaying into two photons. We show that the recorded LHC data for the light-by-light scattering may indeed accommodate for such a state, with a ő≥ő≥\gamma \gamma branching ratio of order of 10‚ąí410^{-4}, which is larger even than the value inferred by the VMD. The spin-parity assignment 0‚ąí+0^{-+} is in better agreement with the VMD prediction than 0++0^{++}, albeit not significantly at the current precision. Further light-by-light scattering data in this region, clarifying the nature of this state, should be obtained in the Run 3 and probably in the high-luminosity phase of the LHC (Run 4 etc.).Comment: 6 pages, 4 figure

    Two-photon decay of fully-charmed tetraquarks from light-by-light scattering at the LHC

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    The LHC newly-discovered resonant structures around 7 GeV, such as the X(6900), could be responsible for the observed excess in light-by-light scattering between 5 and 10 GeV. We show that the ATLAS data for light-bylight scattering may indeed be explained by such a state with the ő≥ő≥ branching ratio of order of 10‚ąí4. This is much larger than the value inferred by the vectormeson dominance, but agrees quite well with the tetraquark expectation for the nature of this state. Further light-by-light scattering data in this region, obtained during the ongoing Run-3 and future Run-4 of the LHC, are required to pin down these states in ő≥ő≥ channel

    First Direct Observation of Collider Neutrinos with FASER at the LHC

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    We report the first direct observation of neutrino interactions at a particle collider experiment. Neutrino candidate events are identified in a 13.6 TeV center-of-mass energy pppp collision data set of 35.4 fb‚ąí1{}^{-1} using the active electronic components of the FASER detector at the Large Hadron Collider. The candidates are required to have a track propagating through the entire length of the FASER detector and be consistent with a muon neutrino charged-current interaction. We infer 153‚ąí13+12153^{+12}_{-13} neutrino interactions with a significance of 16 standard deviations above the background-only hypothesis. These events are consistent with the characteristics expected from neutrino interactions in terms of secondary particle production and spatial distribution, and they imply the observation of both neutrinos and anti-neutrinos with an incident neutrino energy of significantly above 200 GeV.Comment: Submitted to PRL on March 24 202

    The Forward Physics Facility at the High-Luminosity LHC

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    Search for dark matter produced in association with bottom or top quarks in ‚ąös = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb‚ąí1 of proton‚Äďproton collision data recorded by the ATLAS experiment at ‚ąös = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    First neutrino interaction candidates at the LHC

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    FASERőĹ\nu at the CERN Large Hadron Collider (LHC) is designed to directly detect collider neutrinos for the first time and study their cross sections at TeV energies, where no such measurements currently exist. In 2018, a pilot detector employing emulsion films was installed in the far-forward region of ATLAS, 480 m from the interaction point, and collected 12.2 fb‚ąí1^{-1} of proton-proton collision data at a center-of-mass energy of 13 TeV. We describe the analysis of this pilot run data and the observation of the first neutrino interaction candidates at the LHC. This milestone paves the way for high-energy neutrino measurements at current and future colliders.Comment: Auxiliary materials are available at https://faser.web.cern.ch/fasernu-first-neutrino-interaction-candidate

    The FASER Detector

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    FASER, the ForwArd Search ExpeRiment, is an experiment dedicated to searching for light, extremely weakly-interacting particles at CERN's Large Hadron Collider (LHC). Such particles may be produced in the very forward direction of the LHC's high-energy collisions and then decay to visible particles inside the FASER detector, which is placed 480 m downstream of the ATLAS interaction point, aligned with the beam collisions axis. FASER also includes a sub-detector, FASERőĹ\nu, designed to detect neutrinos produced in the LHC collisions and to study their properties. In this paper, each component of the FASER detector is described in detail, as well as the installation of the experiment system and its commissioning using cosmic-rays collected in September 2021 and during the LHC pilot beam test carried out in October 2021. FASER will start taking LHC collision data in 2022, and will run throughout LHC Run 3
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