TY  - JOUR
T1  - Performance of missing transverse momentum reconstruction in proton-proton collisions at  √s=7 TeV with ATLAS
JF  - The European Physical Journal C
N2  - The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 nb\(^{−1}\) and 600 nb\(^{−1}\) respectively, together with events containing a Z boson decaying to two leptons (electrons or muons) or a W boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 pb\(^{−1}\). An estimate of the systematic uncertainty on the missing transverse momentum scale is presented
KW  - momentum scale
KW  - Atlas detector
KW  - pp collision
KW  - systematic uncertainty
KW  - transverse momentum
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127530
VL  - 72
IS  - 1844
ER  - 
TY  - JOUR
T1  - Measurement of τ polarization in W→τν decays with the ATLAS detector in pp collisions at s√=7 TeV
JF  - The European Physical Journal C
N2  - In this paper, a measurement of τ polarization in W→τν decays is presented. It is measured from the energies of the decay products in hadronic τ decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb\(^{−1}\), were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the τ polarization is P\(_τ\)=−1.06±0.04 (stat)\(^{+0.05}_{−0.07}\) (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95 % CL interval [−1,−0.91]. Measurements of τ polarization have not previously been made at hadron colliders.
KW  - total systematic uncertainty
KW  - energy scale uncertainty
KW  - multijet background
KW  - electroweak background
KW  - jet energy
KW  - Monte Carlo methods
KW  - signal template
KW  - track momentum
KW  - calorimeter
KW  - detector track
KW  - transverse momentum
KW  - ATLAS detector
KW  - jet axis
KW  - multijet event
KW  - track multipilicty
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127807
VL  - 72
IS  - 2062
ER  - 
TY  - JOUR
T1  - Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at √s=7 TeV with the ATLAS experiment
JF  - The European Physical Journal C
N2  - This paper describes an analysis of the angular distribution of W→eν and W→μν decays, using data from pp collisions at s√=7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb\(^{−1}\). Using the decay lepton transverse momentum and the missing transverse momentum, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f\(_0\), f\(_L\) and f\(_R\) over two ranges of W transverse momentum (p\(^W_T\)):35<p\(^W_T\)<50 GeV and p\(^W_T\)>50 GeV. Good agreement is found with theoretical predictions. For p\(^W_T\)>50 GeV, the values of f\(_0\) and f\(_L\)−f\(_R\), averaged over charge and lepton flavour, are measured to be: f\(_0\)=0.127±0.030±0.108 and f\(_L\)−f\(_R\)=0.252±0.017±0.030, where the first uncertainties are statistical, and the second include all systematic effects.
KW  - good agreement
KW  - transverse plane
KW  - Atlas detector
KW  - transverse momentum
KW  - helicity fraction
KW  - Pp Collision
KW  - lepton flavour
KW  - systematic effect
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127615
VL  - 72
IS  - 2001
ER  - 
TY  - JOUR
T1  - Rapidity gap cross sections measured with the ATLAS detector in pp collisions at √s=7TeV
JF  - The European Physical Journal C
N2  - Pseudorapidity gap distributions in proton-proton collisions at √s=7 TeV are studied using a minimum bias data sample with an integrated luminosity of 7.1 μb\(^{−1}\). Cross sections are measured differentially in terms of Δη\(^F\), the larger of the pseudorapidity regions extending to the limits of the ATLAS sensitivity, at η=±4.9, in which no final state particles are produced above a transverse momentum threshold pcutT. The measurements span the region 0<Δη\(^F\)<8 for 200MeV<p\(^{cut}_T\)<800MeV. At small Δη\(^F\) , the data test the reliability of hadronisation models in describing rapidity and transverse momentum fluctuations in final state particle production. The measurements at larger gap sizes are dominated by contributions from the single diffractive dissociation process (pp→Xp), enhanced by double dissociation (pp→XY) where the invariant mass of the lighter of the two dissociation systems satisfies M\(_Y\) ≲7 GeV. The resulting cross section is dσ/dΔη\(^F\) ≈1 mb for Δη\(^F\) ≳3. The large rapidity gap data are used to constrain the value of the Pomeron intercept appropriate to triple Regge models of soft diffraction. The cross section integrated over all gap sizes is compared with other LHC inelastic cross section measurements.
KW  - dissociation process,
KW  - transverse momentum
KW  - large rapidity gap
KW  - cross section measurement
KW  - invariant mass
KW  - diffractive dissociation
KW  - hadronisation model
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127629
VL  - 72
IS  - 1926
ER  - 
TY  - JOUR
T1  - Search for supersymmetry in events with large missing transverse momentum, jets, and at least one tau lepton in 7 TeV proton-proton collision data with the
JF  - The European Physical Journal C
N2  - A search for supersymmetry (SUSY) in events with large missing transverse momentum, jets, and at least one hadronically decaying τ lepton, with zero or one additional light lepton (e/μ), has been performed using 4.7 fb\(^{−1}\) of proton-proton collision data at \(\sqrt s\)=7TeV recorded with the ATLAS detector at the Large Hadron Collider. No excess above the Standard Model background expectation is observed and a 95 % confidence level visible cross-section upper limit for new phenomena is set. In the framework of gauge-mediated SUSY-breaking models, lower limits on the mass scale Λ are set at 54 TeV in the regions where the \(\tilde τ_1\) is the next-to-lightest SUSY particle (tanβ>20). These limits provide the most stringent tests to date of GMSB models in a large part of the parameter space considered.
KW  - multi-jet background
KW  - jet energy scale
KW  - systematic uncertainty
KW  - jet background
KW  - anti-k jet
KW  - jet energy resolution
KW  - MC expectation
KW  - GMSB model
KW  - Cl Lowe limit
KW  - transverse momentum
KW  - single top event
KW  - SM background
KW  - MC simulation
KW  - transverse momentum vector
KW  - SUSY breaking scale
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128891
VL  - 72
IS  - 2215
ER  -