Measurement of theBs0→μ+μ−Branching Fraction and Search forB0→

Abstract

A search for the rare decays B 0 s ! þ À and B 0 ! þ À is performed at the LHCb experiment. The data analyzed correspond to an integrated luminosity of 1 fb À1 of pp collisions at a center-of-mass energy of 7 TeV and 2 fb À1 at 8 TeV. An excess of B 0 s ! þ À signal candidates with respect to the background expectation is seen with a significance of 4.0 standard deviations. A time-integrated branching fraction of BðB 0 s ! þ À Þ ¼ ð2:9 þ1:1 À1:0 Þ Â 10 À9 is obtained and an upper limit of BðB 0 ! þ À Þ < 7:4 Â 10 À10 at 95% confidence level is set. These results are consistent with the standard model expectations.

Search for Scalar Top Quarks and Higgsino-Like Neutralinos

“…1.20. The CMS and LHCb collaborations measured the branching ratio of B 0 s → µ + µ − [72,73], and the combined branching ratio is reported to be 2.8 +0.7 −0.6 × 10 −9 [74], which is consistent with the SM expectation. Furthermore, no significant evidences are found in the other rare B meson decays sensitive to the SUSY parameters.…”

Renormalizable model for the Galactic Center gamma-ray excess from dark matter annihilation

“…The average of the LHCb and CMS measurements of this mode is Br (B s → µ + µ − ) = (2.9 ± 0.7) × 10 −9 [24]. This should be compared against the SM prediction, which we take to be (3.65 ± 0.23) × 10 −9 [25].…”

First observation of the rareB+→D+K+π−decay

“…Similar fitting techniques have been used successfully in several previous LHCb analyses [22][23][24][25]. A loose requirement is placed on the output of NN2 and the remaining data in each sample are divided into six bins of the NN2 output variable, each containing a similar number of signal decays.…”