184 research outputs found

    Run 3 luminosity measurements with the Pixel Luminosity Telescope

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    For Run-3 of the LHC, the CMS experiment has installed the pixel luminosity telescope (PLT) which is made of three layers of pixel sensors that count charged particles from each bunch crossing of the LHC beam. The rate of triple-coincidences between layers is translated into a luminosity value that is published about every 1.4 seconds. In addition, at a lower rate, particle trajectories are reconstructed for systematic studies of beam backgrounds and efficiencies. The paper discussed the working principles of luminosity calibrations and results from systematic studies

    The Pixel Luminosity Telescope: a detector for luminosity measurement at CMS using silicon pixel sensors

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    International audienceThe Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 ‚Äútelescopes‚ÄĚ, with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run¬†2 (2015‚Äď18) of the LHC, as well as preparations for Run 3, which will begin in 2022

    Measurement of the double-differential inclusive jet cross section in proton-proton collisions at s\sqrt{s} = 5.02 TeV

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    International audienceThe inclusive jet cross section is measured as a function of jet transverse momentum pTp_\mathrm{T} and rapidity yy. The measurement is performed using proton-proton collision data at s\sqrt{s} = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb‚ąí1^{-1}. The jets are reconstructed with the anti-kTk_\mathrm{T} algorithm using a distance parameter of RR = 0.4, within the rapidity interval ‚ą£y‚ą£\lvert y\rvert<\lt 2, and across the kinematic range 0.06 <\ltpTp_\mathrm{T}<\lt 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling őĪS\alpha_\mathrm{S}

    Search for physics beyond the standard model in top quark production with additional leptons in the context of effective field theory