Sneha Malde

Abstract:

An analysis of B+→KS 0π+ and B+→KS 0K+ decays is performed with the LHCb experiment. The pp collision data used correspond to integrated luminosities of 1fb-1 and 2fb-1 collected at centre-of-mass energies of √s=7TeV and √s=8TeV, respectively. The ratio of branching fractions and the direct CP asymmetries are measured to be B(B+→KS0K+)/B(B+→KS 0π+)=0.064±0.009 (stat.)±0.004(syst.), ACP(B+→KS 0π+)=-0.022±0.025(stat.)±0.010 (syst.) and ACP(B+→KS 0K+)=-0.21±0.14 (stat.)±0.01 (syst.). The data sample taken at √s=7 TeV is used to search for Bc +→KS 0K+ decays and results in the upper limit (fc{dot operator}B(Bc +→KS 0K+))/(fu{dot operator}B(B+→KS 0π+))<5.8×10-2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a b- quark into a Bc+ or a B+ meson, respectively. © 2013 CERN.

Abstract:

The angular distribution and differential branching fraction of the decay B+→ K+μ+μ- are studied with a dataset corresponding to 1.0 fb-1 of integrated luminosity, collected by the LHCb experiment. The angular distribution is measured in bins of dimuon invariant mass squared and found to be consistent with Standard Model expectations. Integrating the differential branching fraction over the full dimuon invariant mass range yields a total branching fraction of β(B +→ K+μ+μ-) = (4:36±0:15±0:18)×10-7. These measurements are the most precise to date of the B+→ K+μ +μ- decay.

Abstract:

The angular distribution and differential branching fraction of the decay B 0→ K * 0 μ + μ - are studied using a data sample, collected by the LHCb experiment in pp collisions at S=7 TeV, corresponding to an integrated luminosity of 1.0 fb -1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q02=4.9± 0.9 GeV2 c4, where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions. [Figure not available: see fulltext.] © 2013 Cern for the benefit of the LHCb collaboration.

Abstract:

A search for the lepton-flavor-violating decays Bs0→e ±μ and B0→e±μ is performed with a data sample, corresponding to an integrated luminosity of 1.0 fb-1 of pp collisions at √s=7 TeV, collected by the LHCb experiment. The observed number of Bs0→e±μ and B0→e ±μ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e±μ)<1.1(1.4)×10-8 and B(B0→e±μ)<2.8(3.7)×10-9 at 90% (95%) confidence level (C.L.). These limits are a factor of 20 lower than those set by previous experiments. Lower bounds on the Pati-Salam leptoquark masses are also calculated, MLQ(Bs0→e±μ)>101 TeV/c2 and MLQ(B0→e±μ)>126 TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds. © 2013 CERN. Published by the American Physical Society under the terms of the http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Abstract:

A study of D + π − , D 0 π + and D* + π − final states is performed using πcollision data, corresponding to an integrated luminosity of 1.0 fb −1 , collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D 1 (2420) 0 resonance is observed in the D* + π − final state and the D* 2 (2460) resonance is observed in the D + π − , D 0 π + and D* + π − final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the D* + π − , D + π − and D 0 π + final states.