Abstract
A search for the rare decays and is performed with data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise of proton-proton collisions at and at . We observe an excess of candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of , where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the standard model expectation. The observed number of candidates is consistent with the background expectation, giving an upper limit of at 95% confidence level.
- Received 12 November 2012
DOI:https://doi.org/10.1103/PhysRevLett.110.021801
This article is available under the terms of the 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.
© 2013 CERN, for the LHCb Collaboration
Viewpoint
Mixed Feelings About a Rare Event
Published 7 January 2013
Measurement of a rare-meson decay is an experimental achievement worth celebrating, but so far, no new physics beyond the standard model is indicated.
See more in Physics