Measurement of the isospin asymmetry in B → K (*) μ + μ - decays
Journal
Journal of High Energy Physics
Journal Volume
2012
Journal Issue
7
Date Issued
2012
Author(s)
Aaij, R. et al. (LHCb Collaboration)
Abstract
The isospin asymmetries of B → K(*)μ +μ- decays and the partial branching fractions of B0 → K0μ+μ- and B +→ K*+μ+μ- are measured as a function of the di-muon mass squared q2 using an integrated luminosity of 1.0fb-1 collected with the LHCb detector. The B → Kμ+μ- isospin asymmetry integrated over q2 is negative, deviating from zero with over 4 σ significance. The B → K*μ+μ- decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay B0 → Ks0μ+μ- is reported with 5.7 σ significance. Assuming that the branching fraction of B0 → K0μ+μ- is twice that of B 0 → Ks0μ+μ-, the branching fractions of B0 → K0μ +μ- and B → K*+μ +μ- are found to be (0.31+0.07 -0.06) × 10-6 and (1.16 ±0.19) × 10-6, respectively.
Type
journal article