First exclusive reconstruction of the B${}^{\ast +}$, B${}^{\ast 0}$, and B${}_{\text{s}}^{\ast 0}$ 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}$, the first full reconstruction of the three vector B meson states, B${}^{\ast +}$, B${}^{\ast 0}$, and B${}_{\text{s}}^{\ast 0}$, is performed. The mass differences between the excited mesons and their corresponding ground states are measured to be $m({\text{B}}^{\ast +})-m({\text{B}}^{+})$ = 45.277 $\pm$ 0.039 $\pm$ 0.027 MeV, $m({\text{B}}^{\ast 0})-m({\text{B}}^0)$ = 45.471 $\pm$ 0.056 $\pm$ 0.028 MeV, and $m({\text{B}}_{\text{s}}^{\ast 0})-m({\text{B}}_{\text{s}})$ = 49.407 $\pm$ 0.132 $\pm$ 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.