Sneha Malde

Abstract:

A search for the rare decays B0s→μ+μ− and B0→μ+μ− is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4  fb−1. An excess of B0s→μ+μ− decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B0s→μ+μ−)=(3.0±0.6+0.3−0.2)×10^−9, where the first uncertainty is statistical and the second systematic. The first measurement of the B0s→μ+μ− effective lifetime, τ(B0s→μ+μ−)=2.04±0.44±0.05  ps, is reported. No significant excess of B0→μ+μ− decays is found, and a 95% confidence level upper limit, B(B0→μ+μ−)<3.4×10^−10, is determined. All results are in agreement with the standard model expectations.

Abstract:

The Ξ+cK− mass spectrum is studied with a sample of pp collision data corresponding to an integrated luminosity of 3.3  fb^-1, collected by the LHCb experiment. The Ξ+cK− is reconstructed in the decay mode pK-π+. Five new, narrow excited Ω0c states are observed: the Ωc(3000)^0, Ωc(3050)^0, Ωc(3066)^0, Ωc(3090)^0, and Ωc(3119)^0. Measurements of their masses and widths are reported.

Abstract:

A search for the charmless $B^{0}_{s} \to \eta^{\prime}\phi$ decay is performed using $pp$ collision data collected by the LHCb experiment at centre-of-mass energies of $7$ and $8$ TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$. No signal is observed and upper limits on the $B^{0}_{s} \to \eta^{\prime}\phi$ branching fraction are set to $0.82\times 10^{-6}$ at $90\%$ and $1.01\times 10^{-6}$ at $95\%$ confidence level.

Abstract:

An amplitude analysis of the decay Λb0 → D0pπ− is performed in the part of the phase space containing resonances in the D0p channel. The study is based on a data sample corresponding to an integrated luminosity of 3.0fb^−1 of pp collisions recorded by the LHCb experiment. The spectrum of excited Λc+ states that decay into D0p is studied. The masses, widths and quantum numbers of the Λc(2880)+ and Λc (2940) + resonances are measured. The constraints on the spin and parity for the Λc(2940)+ state are obtained for the first time. A near-threshold enhancement in the D0p amplitude is investigated and found to be consistent with a new resonance, denoted the Λc(2860)+ , of spin 3/2 and positive parity.