A joint measurement is presented of the branching fractions B0s→μ+μ− and B0→μ+μ− in proton-proton collisions at the LHC by the CMS and LHCb experiments. The data samples were collected in 2011 at a centre-of-mass energy of 7 TeV, and in 2012 at 8 TeV. The combined analysis produces the first observation of the B0s→μ+μ− decay, with a statistical significance exceeding six standard deviations, and the best measurement of its branching fraction so far, and three standard deviation evidence for the B0→μ+μ− decay. The measurements are statistically compatible with SM predictions and impose stringent constraints on several theories beyond the SM.
from HAL : Dernières publications http://ift.tt/1pxeyHF
from HAL : Dernières publications http://ift.tt/1pxeyHF

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