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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Searches for heavy long-lived sleptons and R-hadrons with the ATLAS detector in pp collisions at root s=7 TeV. Phys. Lett. B, 720(4-5), 277–308.
Abstract: A search for long-lived particles is performed using a data sample of 4.7 fb(-1) from proton-proton collisions at a centre-of-mass energy. root s = 7 TeV collected by the ATLAS detector at the LHC. No excess is observed above the estimated background and lower limits, at 95% confidence level, are set on the mass of the long-lived particles in different scenarios, based on their possible interactions in the inner detector, the calorimeters and the muon spectrometer. Long-lived staus in gauge-mediated SUSY-breaking models are excluded up to a mass of 300 GeV for tan beta = 5-20. Directly produced long-lived sleptons are excluded up to a mass of 278 GeV. R-hadrons, composites of gluino (stop, sbottom) and light quarks, are excluded up to a mass of 985 GeV (683 GeV, 612 GeV) when using a generic interaction model. Additionally two sets of limits on R-hadrons are obtained that are less sensitive to the interaction model for R-hadrons. One set of limits is obtained using only the inner detector and calorimeter observables, and a second set of limits is obtained based on the inner detector alone.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Search for WH production with a light Higgs boson decaying to prompt electron-jets in proton-proton collisions at root s=7 TeV with the ATLAS detector. New J. Phys., 15, 043009–35pp.
Abstract: A search is performed for WH production with a light Higgs boson decaying to hidden-sector particles resulting in clusters of collimated electrons, known as electron-jets. The search is performed with 2.04 fb(-1) of data collected in 2011 with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at root s = 7 TeV. One event satisfying the signal selection criteria is observed, which is consistent with the expected background rate. Limits on the product of the WH production cross section and the branching ratio of a Higgs boson decaying to prompt electron-jets are calculated as a function of a Higgs boson mass in the range from 100 to 140 GeV.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2012). Search for top and bottom squarks from gluino pair production in final states with missing transverse energy and at least three b-jets with the ATLAS detector. Eur. Phys. J. C, 72(10), 2174–19pp.
Abstract: This letter reports the results of a search for top and bottom squarks from gluino pair production in 4.7 fb(-1) of pp collisions at root s = 7 TeV using the ATLAS detector at the LHC. The search is performed in events with large missing transverse momentum and at least three jets identified as originating from a b-quark. Exclusion limits are presented for a variety of gluino-mediated models with gluino masses up to 1 TeV excluded.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Search for third generation scalar leptoquarks in pp collisions at root s=7 TeV with the ATLAS detector. J. High Energy Phys., 06(6), 033–40pp.
Abstract: A search for pair-produced third generation scalar leptoquarks is presented, using proton-proton collisions at root s = 7 TeV at the LHC. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 4.7 fb(-1). Each leptoquark is assumed to decay to a tau lepton and a b-quark with a branching fraction equal to 100%. No statistically significant excess above the Standard Model expectation is observed. Third generation leptoquarks are therefore excluded at 95% confidence level for masses less than 534 GeV.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2012). Search for the Standard Model Higgs boson produced in association with a vector boson and decaying to a b-quark pair with the ATLAS detector. Phys. Lett. B, 718(2), 369–390.
Abstract: This Letter presents the results of a direct search with the ATLAS detector at the LHC for a Standard Model Higgs boson of mass 110 <= m(H) <= 130 GeV produced in association with a W or Z boson and decaying to b (b) over bar. Three decay channels are considered: ZH -> l(+)l(-)b (b) over bar, WH -> lvbb (b) over bar and ZH -> v (v) over bar(b) over bar where l corresponds to an electron or a muon. No evidence for Higgs boson production is observed in a dataset of 7 TeV pp collisions corresponding to 4.7 fb(-1) of integrated luminosity collected by ATLAS in 2011. Exclusion limits on Higgs boson production, at the 95% confidence level, of 2.5 to 5.5 times the Standard Model cross section are obtained in the mass range 110-130 GeV. The expected exclusion limits range between 2.5 and 4.9 for the same mass interval.
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