First Exclusive Reconstruction of the B*+, B*0, and Bs*0 Mesons and Precise Measurement of Their Masses

Using proton-proton collision data collected by the CMS experiment at root s = 13 TeV in 2016-2018, corresponding to an integrated luminosity of 140 fb(-1), the first full reconstruction of the three vector B meson states, B*(+), B-*0, and B-s(*0), is performed. The mass differences between the excited mesons and their corresponding ground states are measured to be m(B*(+)) - m(B+) 45.277 +/- 0.039 +/- 0.027 MeV, m(B*(0))- m(B-0) = 45.471 +/- 0.056 +/- 0.028 MeV, and m(B-s(0)) - m(B-s(0)) = 49.407 +/- 0.132 +/- 0.041 MeV, where the first uncertainties are statistical and the second are systematic. These results improve on the precision of previous measurements by an order of magnitude.