Studies of and mesons including the observation of the decay in proton-proton collisions at

Measurements of $$ and $$ mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of , collected with the CMS detector at the LHC at a centre-of-mass energy of $$ . The analysis studies P-wave $$ meson decays into $$ and $$ , where the $$ and $$ mesons are identified using the decays $$ and $$ . The masses of the P-wave $$ meson states are measured and the natural width of the $$ state is determined. The first measurement of the mass difference between the charged and neutral $$ mesons is also presented. The $$ decay to $$ is observed, together with a measurement of its branching fraction relative to the $$ decay.