A.J.M. Muijs

Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

This Letter describes the measurement of √ elliptic flow of charged particles in lead–lead collisions at √sNN = 2.76 TeV using the ATLAS detector at the Large Hadron Collider (LHC). The results are based on an integrated luminosity of approximately 7 μb^(−1). Elliptic flow is measured over a wide region in pseudorapidity, |η| < 2.5, and over a broad range in transverse momentum, 0.5 < p_T < 20 GeV. The elliptic flow parameter v_2 is obtained by correlating individual tracks with the event plane measured using energy deposited in the forward calorimeters. As a function of transverse momentum, v_2(p_T) reaches a maximum at p_T of about 3 GeV, then decreases and becomes weakly dependent on p_T above 7–8 GeV. Over the measured pseudorapidity region, v_2 is found to be only weakly dependent on η, with less variation than observed at lower beam energies. The results are discussed in the context of previous measurements at lower collision energies, as well as recent results from the LHC.

Single- and multi-photon events with missing energy in e+e - collisions at LEP

Single-and multi-photon events with missing energy are selected in 619 pb −1 of data collected by the L3 detector at LEP at centre-of-mass energies between 189 GeV and 209 GeV. The cross sections of the process e + e − → ν ¯ νγ(γ) are found to be in agreement with the Standard Model expectations, and the number of light neutrino species is determined, including lower energy data, to be N ν = 2.98 ± 0.05 ± 0.04. Selection results are given in the form of tables which can be used to test future models involving single-and multi-photon signatures at LEP. These final states are also predicted by models with large extra dimensions and by several supersymmetric models. No evidence for such models is found. Among others, lower limits between 1.5 TeV and 0.65 TeV are set, at 95% confidence level, on the new scale of gravity for the number of extra dimensions between 2 and 8.

Search for supersymmetry using final states with one lepton, jets, and missing transverse momentum with the ATLAS detector in √s = 7 TeV pp collisions

This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from √s=7  TeV proton-proton collisions at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35  pb(-1). No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. Within this framework, for A(0)=0 GeV, tanβ=3, and μ>0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidence level.This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from √ s = 7 TeV proton-proton collisions at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35 pb. No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. For A0 = 0 GeV, tanβ = 3, μ > 0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidence level.

Search for new physics in energetic single photon production in

Using a sample of

e^{+}e^{-}

\mathrm{e^{+}e^{-}}

annihilation at the

annihilation events collected with the L3 detector at the Z resonance corresponding to an integrated luminosity of 137 pb

Z

^{-1}

resonance

, we have searched for anomalous production of

Cross-section of hadron production in

\gamma \mathrm{X}

\gamma\gamma

final states where