First Exclusive Reconstruction of the B$^{*+}$, B$^{*0}$, and B$^{*0}_s$ 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$^{*0}_𝑠$, 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$^{*0}_𝑠$)−𝑚⁡(𝐵$^0_𝑠$)=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.