Precision measurement of the $\hat{I}{ž}_{cc}^{++}$ mass

Abstract

A measurement of the $\hat{I}{ž}_{cc}^{++}$ mass is performed using data collected by the LHCb experiment between 2016 and 2018 in $pp$ collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 ${\mathrm{fb}}^{-1}$. The $\hat{I}{ž}_{cc}^{++}$ candidates are reconstructed via the decay modes $\hat{I}{ž}_{cc}^{++}\to \hat{I}{›}_c^{+}{K}^{-}\ddot{I}{€}^{+}\ddot{I}{€}^{+}$ and $\hat{I}{ž}_{cc}^{++}\to \hat{I}{ž}_c^{+}\ddot{I}{€}^{+}$. The result, $3621.55\pm 0.23(\mathrm{stat})\pm 0.30(\mathrm{syst})\mathrm{MeV}/c^2$, is the most precise measurement of the $\hat{I}{ž}_{cc}^{++}$ mass to date.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-037.html