B. Van Eijk

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.

Calculating QCD corrections to single top production in hadronic interactions

Abstract We give a detailed expose on the calculation of O( α s ) corrections to the cross section for the semiweak production of single top quarks in hadronic interactions. After introducing the different sub-processes and defining their kinematics, we briefly recall the computation of the O (α 2 ) qb → q′t and O (α s α 2 ) qg → q′t b Born amplitudes squared. Next, the calculation of virtual and bremsstrahlung corrections is presented. We adopt a massive quark and massive gluon regularisation scheme. We explicitly demonstrate cancellations among various radiative corrections and we describe the procedure of absorbing remaining singularities in the parton density distribution functions. Finally, numerical results are given. We find a cross-section enhancement of roughly 30% (for m t ≈ 174 GeV/ c 2 ) with respect to the Born contribution. We observe good agreement between the exact calculation and the approach where the mass singularity is subtracted from the sum of the O ( α 2 ) and O ( α s α 2 ) tree-level expressions.

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.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/

Review of the development of diamond radiation sensors

c

Pulse height distribution and radiation tolerance of CVD diamond detectors

and 500~MeV protons up to a fluence of

Heavy flavour production in large transverse momentum proton-antiproton collisions

5\times 10^{15}~p/{\rm cm^2}

Properties of jets measured from tracks in proton-proton collisions at center-of-mass energy root s=7 TeV with the ATLAS detector

. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to

Status of the R&D activity on diamond particle detectors

1\ times 10^{15}~p/{\rm cm^2}

CVD diamond detectors for ionizing radiation

and decreases by