Search for the doubly charmed baryon $\hat{I}{ž}_{cc}^{+}$

Abstract

A search for the doubly charmed baryon $\hat{I}{ž}_{cc}^{+}$ is performed through its decay to the $\hat{I}{›}_c^{+}{K}^{-}\ddot{I}{€}^{+}$ final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13$\mathrm{Te}\mathrm{V}$. The data correspond to a total integrated luminosity of $9{\mathrm{fb}}^{-1}$. No significant signal is observed in the mass range from 3.4 to 3.8$\mathrm{Ge}\mathrm{V}/c^2$. Upper limits are set at $95\%$ credibility level on the ratio of the $\hat{I}{ž}_{cc}^{+}$ production cross-section times the branching fraction to that of $\hat{I}{›}_c^{+}$ and $\hat{I}{ž}_{cc}^{++}$ baryons. The limits are determined as functions of the $\hat{I}{ž}_{cc}^{+}$ mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15$\mathrm{Ge}\mathrm{V}/c$.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-029.html