First evidence for the decay Bs0→μ+ μ-
Journal
Physical Review Letters
Journal Volume
110
Journal Issue
2
Date Issued
2013
Author(s)
Aaij, R. et al. (LHCb Collaboration)
Abstract
A search for the rare decays B(s)(0)���g+ �g- and B(0)���g+ �g- is performed with data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb(-1) of proton-proton collisions at sqrt[s]=8 TeV and 1.0 fb(-1) at sqrt[s]=7 TeV. We observe an excess of B(s)(0)���g+ �g- candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is 5.3��10(-4) corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of B(B(s)(0)���g+ �g-)=(3.2(-1.2)(+1.5))��10(-9), where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the standard model expectation. The observed number of B(0)���g+ �g- candidates is consistent with the background expectation, giving an upper limit of B(B(0)���g+ �g-)<9.4��10(-10) at 95% confidence level.
Type
journal article