Search results for "dilepton"
showing 10 items of 39 documents
Forward rapidity isolated photon production in proton-nucleus collisions
2018
We calculate isolated photon production at forward rapidities in proton-nucleus collisions in the Color Glass Condensate framework. Our calculation uses dipole cross sections solved from the running coupling Balitsky-Kovchegov equation with an initial condition fit to deep inelastic scattering data and extended to nuclei with an optical Glauber procedure that introduces no additional parameters beyond the basic nuclear geometry. We present predictions for future forward RHIC and LHC measurements. The predictions are also compared to updated results for the nuclear modification factors for pion production, Drell-Yan dileptons and $J/\psi$ mesons in the same forward kinematics, consistently c…
Evidence for the production of three massive vector bosons with the ATLAS detector
2019
A search for the production of three massive vector bosons in proton–proton collisions is performed using data at TeV recorded with the ATLAS detector at the Large Hadron Collider in the years 2015–2017, corresponding to an integrated luminosity of 79.8 fb−1. Events with two same-sign leptons ℓ (electrons or muons) and at least two reconstructed jets are selected to search for . Events with three leptons without any same-flavour opposite-sign lepton pairs are used to search for , while events with three leptons and at least one same-flavour opposite-sign lepton pair and one or more reconstructed jets are used to search for . Finally, events with four leptons are analysed to search for and .…
Precise measurement of the top quark mass in dilepton decays using optimized neutrino weighting
2016
We measure the top quark mass in dilepton final states of top-antitop events in proton-antiproton collisions at sqrt(s) = 1.96 TeV, using data corresponding to an integrated luminosity of 9.7 fb^-1 at the Fermilab Tevatron Collider. The analysis features a comprehensive optimization of the neutrino weighting method to minimize the statistical uncertainties. We also improve the calibration of jet energies using the calibration determined in top-antitop to lepton+jets events, which reduces the otherwise limiting systematic uncertainty from the jet energy scale. The measured top quark mass is mt = 173.32 +/- 1.36(stat) +/- 0.85(syst) GeV.
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7$ TeV
2011
A measurement of the production cross-section for top quark pairs($\ttbar$) in $pp$ collisions at $\sqrt{s}=7 \TeV$ is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-$\ttbar$ Standard Model processes are estimated using data-driv…
Pion–nucleus Drell–Yan data as a novel constraint for nuclear PDFs
2017
We have studied the prospects of using the Drell-Yan dilepton process in pion-nucleus collisions as a novel input in the global analysis of nuclear parton distribution functions (nPDFs). In a NLO QCD framework, we find the measured nuclear cross-section ratios from the NA3, NA10 and E615 experiments to be largely insensitive to the pion parton distributions and also compatible with the EPS09 and nCTEQ15 nPDFs. These data sets can thus be, and in EPPS16 have been, included in global nPDF analyses without introducing significant new theoretical uncertainties or tension with the other data. In particular, we explore the constraining power of these data sets on the possible flavour asymmetry in…
"Dielectron invariant mass spectrum" of "Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=$…
2019
Distribution of the dielectron invariant mass for events passing the full selection.
"Observed exclusion contours on HVT $\{g_q,g_l\}$ at 3 TeV" of "Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data c…
2019
Observed 95% exclusion contours in the HVT parameter space $\{g_q,g_l\}$ with $g_h$ set to zero for a resonance mass of 3 TeV for the dilepton channel. The area outside the curves is excluded.
"Observed exclusion contours on HVT $\{g_h,g_f\}$ at 5 TeV" of "Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data c…
2019
Observed 95% exclusion contours in the HVT parameter space $\{g_h,g_f\}$ with $g_f\equiv g_l=g_q$ for a resonance mass of 5 TeV for the dilepton channel. The area outside the curves is excluded.
"Observed dielectron cross-section limits" of "Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data collected at $\sqr…
2019
Observed upper limits at 95% CL on the fiducial cross-section times branching ratio as a function of pole mass for the zero-width, 0.5%, 1.2%, 3%, 6% and 10% relative width signals for the dielectron channel.
"Observed dimuon cross-section limits" of "Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}…
2019
Observed upper limits at 95% CL on the fiducial cross-section times branching ratio as a function of pole mass for the zero-width, 0.5%, 1.2%, 3%, 6% and 10% relative width signals for the dimuon channel.