In this document the results of the ATLAS J/Ψ studies on very early LHC proton-proton
s
=
7
TeV
data are shown. The double differential cross-section is measured with respect to the transverse ...momentum and rapidity of the J/Ψ on 9.5 nb
−
1 of integrated luminosity. The non-prompt to prompt cross-section ratio using 17.5 nb
−1 as a function of the J/Ψ transverse momentum has been estimated.
An angular analysis of the decay Bd0 → K∗μ+μ− is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC. The study is using 20.3 fb−1 of integrated luminosity ...collected during 2012 at centre-of-mass energy of s=8\ \sqrt{s}=8 \ TeV. Measurements of the K* longitudinal polarisation fraction and a set of angular parameters obtained for this decay are presented. The results are compatible with the Standard Model predictions.
A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb ...Formula omitted of Formula omitted TeV proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge bosons; direct production of chargino pairs, which in turn decay into leptons and the lightest neutralino via intermediate sleptons; and slepton pair production, where each slepton decays directly into the lightest neutralino and a lepton. No significant deviations from the Standard Model expectation are observed and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles in each of these scenarios. For a massless lightest neutralino, masses up to 580 GeV are excluded for the associated production of the next-to-lightest neutralino and the lightest chargino, assuming gauge-boson mediated decays, whereas for slepton-pair production masses up to 500 GeV are excluded assuming three generations of mass-degenerate sleptons.
It has been found that Figure 30 shows the 68% and 99% confidence-level contours for the W boson and top quark mass measurements, instead of the 68% and 95% confidence-level contours, as stated in ...the legend.
The performance of the missing transverse momentum ( Formula omitted) reconstruction with the ATLAS detector is evaluated using data collected in proton-proton collisions at the LHC at a ...centre-of-mass energy of 13 TeV in 2015. To reconstruct Formula omitted, fully calibrated electrons, muons, photons, hadronically decaying Formula omitted, and jets reconstructed from calorimeter energy deposits and charged-particle tracks are used. These are combined with the soft hadronic activity measured by reconstructed charged-particle tracks not associated with the hard objects. Possible double counting of contributions from reconstructed charged-particle tracks from the inner detector, energy deposits in the calorimeter, and reconstructed muons from the muon spectrometer is avoided by applying a signal ambiguity resolution procedure which rejects already used signals when combining the various Formula omitted contributions. The individual terms as well as the overall reconstructed Formula omitted are evaluated with various performance metrics for scale (linearity), resolution, and sensitivity to the data-taking conditions. The method developed to determine the systematic uncertainties of the Formula omitted scale and resolution is discussed. Results are shown based on the full 2015 data sample corresponding to an integrated luminosity of Formula omitted.
A measurement of the mass of the W boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding ...to Formula omitted of integrated luminosity. The selected data sample consists of Formula omitted candidates in the Formula omitted channel and Formula omitted candidates in the Formula omitted channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yielding mW=80370±7(stat.)±11(exp. syst.)±14(mod. syst.)MeV=80370±19MeV,where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the Formula omitted and Formula omitted bosons yields Formula omitted MeV.
A search for neutral heavy resonances is performed in the
decay channel using
collision data corresponding to an integrated luminosity of
, collected at a centre-of-mass energy of 13
by the ATLAS ...detector at the Large Hadron Collider. No evidence of such heavy resonances is found. In the search for production via the quark-antiquark annihilation or gluon-gluon fusion process, upper limits on
as a function of the resonance mass are obtained in the mass range between 200
and up to 5
for various benchmark models: a Higgs-like scalar in different width scenarios, a two-Higgs-doublet model, a heavy vector triplet model, and a warped extra dimensions model. In the vector-boson fusion process, constraints are also obtained on these resonances, as well as on a Higgs boson in the Georgi-Machacek model and a heavy tensor particle coupling only to gauge bosons.
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