Search for high-mass dilepton resonances using 139 fb−1 of pp collision data collected at s=13 TeV with the ATLAS detector

Abstract

Search for high-mass dilepton resonances using139 fb −1 of p p collision data collected at √ s = 13 TeV with the ATLAS detectorThe ATLAS Collaboration A search for high-mass dielectron and dimuon resonances in the mass range of 250 GeV to 6 TeV is presented. The data were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of √ s = 13 TeV during Run 2 of the Large Hadron Collider and correspond to an integrated luminosity of 139 fb −1 . A functional form is fitted to the dilepton invariant-mass distribution to model the contribution from background processes, and a generic signal shape is used to determine the significance of observed deviations from this background estimate. No significant deviation is observed and upper limits are placed at the 95% confidence level on the fiducial cross-section times branching ratio for various resonance width hypotheses. The derived limits are shown to be applicable to spin-0, spin-1 and spin-2 signal hypotheses. For a set of benchmark models, the limits are converted into lower limits on the resonance mass and reach 4.5 TeV for the E 6 -motivated Z ψ boson. Also presented are limits on Heavy Vector Triplet model couplings.ATLAS [14-16] is a multipurpose detector with a forward-backward symmetric cylindrical geometry with respect to the LHC beam axis.1 The innermost layers consist of tracking detectors in the pseudorapidity range |η| < 2.5. This inner detector (ID) is surrounded by a thin superconducting solenoid that provides a 1 ATLAS uses a right-handed coordinate system with its origin at the nominal interaction point (IP) in the centre of the detector and the z-axis along the beam pipe. The x-axis points from the IP to the centre of the LHC ring, and the y-axis points upwards. Cylindrical coordinates (r, φ) are used in the transverse plane, φ being the azimuthal angle around the z-axis. The pseudorapidity is defined in terms of the polar angle θ as η = − ln tan(θ/2). Angular distance is measured in units of ∆R ≡ (∆η) 2 + (∆φ) 2 .

Probing new neutral gauge bosons with CEνNS and neutrino-electron scattering

“…1 for the case of SNS (reactor) experiments. From this analysis, it becomes evident that for all the setups the sensitivities are rather poor compared to current bounds from the LHC [6], i.e. we find that M Z 125 GeV at 90% C.L.…”

“…with the radiative corrections ρ νe = 1.0128 andκ νe = 0.9963. (1) and (6) for CEνNS and ν e − e − scattering, respectively.…”

“…Searches for heavy intermediate vector bosons have been extensively performed using high energy accelerators such as the LHC [6]. Their existence could also have important implications for electroweak precision tests [7][8][9] and induce charged lepton flavor violation [10,11].…”

Suppressed flavor violation in lepton flavored dark matter from an extra dimension

“…In order to demonstrate how the KK resonance bounds depend on the model parameters (in particular, the bulk masses), we choose four benchmarks, listed in table A 8 1 1 5 B 8 1 1 3 C 8 1 -1 5 D 9 -1 1 5 Table 1: Four benchmarks for bulk masses to be used in our study of KK resonance bounds. For each of these choices, we will also vary M q L. Figure 15: Constraints on the mass of the KK-Z (dashed lines) and the KK gluon (solid lines) for the benchmarks A through D and for several values of M q L, based on dilepton [62] and dijet resonance searches [63], respectively.…”

“…In figure 15, we plot the constraints on the mass of the KK Z-boson and the KK gluon (first KK mode in each case), based respectively on dilepton resonance searches [62] and dijet resonance searches [63], as we vary M q L for each of the four benchmarks A through D. The limits are extracted by performing a Monte Carlo scan over the BLKT coefficients (quarks as well as leptons) as before, and the exclusion curve corresponds to 95% of the trials resulting in resonant production cross sections consistent with the experimental bounds (1000 trials per point). There are two main takeaway points from this figure, namely that the KK gluon bound is the dominant one, pushing the KK scale π/L to values close to 10 TeV, and that the resonance bounds are fairly insensitive to the bulk mass parameters.…”