3,127 research outputs found

    Early ATLAS B-physics with the first 10 – 100 pb-1

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    Early data of ATLAS will allow several B-physics measurements. Already with few pb-1 the ratio of the cross section of prompt J/ψ to indirect J/ψ cross-section will be measured with statistical precision of <5%. With 10 pb−1, the cross section of heavy quarkonia like J/Κ and Y will be measured in a pT range from 10-50 GeV/c. The J/y and Y polarization is expected to be measured with a precision of 0.02 to 0.06 and 0.2 for Y, respectively. Another measurement with first data will be the estimation of the cross section of the exclusive decay B+ →J/yK+, which will be used as a reference channel for e.g. rare B-decay searches as well as for detector performance studies. The measurement of the invariant masses of the B-mesons and lifetimes using these decays will allow detector performance checks

    Early ATLAS B-physics with the first 10 - 100 pb-1

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    The B-physics program of the ATLAS experiment at the LHC with the early data is presented. These data will allow us to measure the production cross sections for B hadrons and heavy quarkonia in pp collisions at a center-of-mass energy of 14 TeV to a reasonable precision. The B-physics trigger scheme employing single or di-muon algorithms is discussed. The potential for extracting the polarization of vector states from the decays J/ψ→ ÎŒ+Ό− and ΄→ ÎŒ+Ό− is also presented

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector