734 research outputs found

    Event characterization of dark bosons via exotic Higgs decays with final states of displaced dimuons in high luminosity era of the LHC

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    We investigate the potential reach of a search for a long-lived/prompt dark vector boson ZDZ_D, also called dark ZZ, and a prompt dark Higgs boson hDh_D through exotic decays of the observed Higgs boson hh into either ZDZDZ_DZ_D, hDhDh_Dh_D, or ZZDZZ_D with ZZ being the hypercharge gauge boson. The ZDZ_D production through the Higgs portal is completed via one of two mechanisms, kinetic mixing of ZDZ_D with ZZ and the mixing of hDh_D with hh. All production modes of hh are considered, while the branching fractions are calculated in Monte Carlo simulation using the {\textsc{MadGraph5}}\_aMC@NLO v2.7.2 framework. We focus on a final state of multiple dimuons, displaced up to \mbox{7500 mm}, where the muons can be reconstructed without vertex constraint using data from ATLAS and CMS detectors to be collected in Run~3. Integrated luminosities of 137, 300, and 3000 fb‚ąí1^{-1} for Run~2, Run~3, and high luminosity run (HL-LHC), respectively, are used for estimating the expected search sensitivity of the Large Hadron Collider to each of the decay modes.Comment: 4 pages, 3 figures, ICHEP202

    Single-photon emission associated with double electron capture in F9+ + C collisions

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    Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.Comment: Submitted to Phys. Rev.

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV