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Azizi, K., Bayar, M., Ozpineci, A., Sarac, Y., & Sundu, H. (2012). Semileptonic transition of Sigma(b) to Sigma in light cone QCD sum rules. Phys. Rev. D, 85(1), 016002–8pp.
Abstract: We use distribution amplitudes of the light Sigma baryon and the most general form of the interpolating current for heavy Sigma(b) baryon to investigate the semileptonic Sigma(b) -> Sigma l(+)l(-) transition in light cone QCD sum rules. We calculate all 12 form factors responsible for this transition and use them to evaluate the branching ratio of the considered channel. The order of branching fraction shows that this channel can be detected at LHC.
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Aydin, S. et al, Gadea, A., & Huyuk, T. (2012). High-spin structure and intruder excitations in Cl-36. Phys. Rev. C, 86(2), 024320–13pp.
Abstract: Excited states up to J(pi) = 11(-) at 10 296 keV and J(pi) = 10(+) at 10 707 keV have been populated in the odd-odd Cl-36 nucleus using the Mg-24(N-14,2p) fusion-evaporation reaction at E-lab = 31 MeV. Twenty new states and 62 new gamma transitions have been identified by employing gamma-gamma and gamma-gamma-gamma coincidences. Lifetimes have been investigated by the Doppler shift attenuation method. The experimental data have been compared with the results of large-scale shell-model calculations performed using different effective interactions and model spaces allowing particle-hole excitations across the N = Z = 20 shell gap.
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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). Underlying event characteristics and their dependence on jet size of charged-particle jet events in pp collisions at root(s)=7 TeV with the ATLAS detector. Phys. Rev. D, 86(7), 072004–34pp.
Abstract: Distributions sensitive to the underlying event are studied in events containing one or more chargedparticle jets produced in pp collisions at root s = 7 TeV with the ATLAS detector at the Large Hadron Collider (LHC). These measurements reflect 800 μb(-1) of data taken during 2010. Jets are reconstructed using the anti-k(t) algorithm with radius parameter R varying between 0.2 and 1.0. Distributions of the charged-particle multiplicity, the scalar sum of the transverse momentum of charged particles, and the average charged-particle p(T) are measured as functions of p(T)(jet) in regions transverse to and opposite the leading jet for 4 GeV < p(T)(jet) < 100 GeV. In addition, the R dependence of the mean values of these observables is studied. In the transverse region, both the multiplicity and the scalar sum of the transverse momentum at fixed p(T)(jet) vary significantly with R, while the average charged- particle transverse momentum has a minimal dependence on R. Predictions from several Monte Carlo tunes have been compared to the data; the predictions from Pythia 6, based on tunes that have been determined using LHC data, show reasonable agreement with the data, including the dependence on R. Comparisons with other generators indicate that additional tuning of soft-QCD parameters is necessary for these generators. The measurements presented here provide a testing ground for further development of the Monte Carlo models.
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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 decay B-s(0) -> mu(+)mu(-) with the ATLAS detector. Phys. Lett. B, 713(4-5), 387–407.
Abstract: A blind analysis searching for the decay B-s(0) -> mu(+)mu(-) has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. With an integrated luminosity of 2.4 fb(-1) no excess of events over the background expectation is found and an upper limit is set on the branching fraction BR(B-s(0) -> mu(+)mu(-)) <2.2(1.9) x 10(-8) at 95% (90%) confidence level.
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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). A search for t (t)over-bar resonances with the ATLAS detector in 2.05 fb(-1) of proton-proton collisions at root s=7 TeV. Eur. Phys. J. C, 72(7), 2083–23pp.
Abstract: A search for top quark pair resonances in final states containing at least one electron or muon has been performed with the ATLAS experiment at the CERN Large Hadron Collider. The search uses a data sample corresponding to an integrated luminosity of 2.05 fb(-1), which was recorded in 2011 at a proton-proton centre-of-mass energy of 7 TeV. No evidence for a resonance is found and limits are set on the production cross-section times branching ratio to t (t) over bar for narrow and wide resonances. For narrow Z' bosons, the observed 95 % Bayesian credibility level limits range from 9.3 pb to 0.95 pb for masses in the range of m(Z') = 500 GeV to m(Z') = 1300 GeV. The corresponding excluded mass region for a leptophobic topcolour Z' boson (Kaluza-Klein gluon excitation in the Randall-Sundrum model) is m(Z') < 880 GeV (m(gKK) < 1130 GeV).
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