First Exclusive Reconstruction of the B^{*+}, B^{*0}, and B_{s}^{*0} Mesons and Precise Measurement of Their Masses

Using proton-proton collision data collected by the CMS experiment at sqrt[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.