Search for the doubly heavy baryon $\it{\Xi}_{bc}^{+}$ decaying to $J/\it{\psi} \it{\Xi}_{c}^{+}$

TL;DR

This paper reports the first search for the doubly heavy baryon c^{+} decaying to J/\u03psi ^{+} using LHCb data, observing potential signals near 6571 and 6694 MeV/c^2, and setting upper limits on production cross-section.

Contribution

It presents the first experimental search for c^{+} decay to J/^{+} and provides upper limits on its production relative to B_c^{+}.

Findings

Two peaking structures observed near 6571 and 6694 MeV/c^2.

Significance of peaking structures: 2.8 and 2.4 standard deviations.

Upper limits set on c^{+} production cross-section.

Abstract

A first search for the $\it{\Xi}_{bc}^{+}\to J/\it{\psi}\it{\Xi}_{c}^{+}$ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of $9\,\mathrm{fb}^{-1}$ recorded at centre-of-mass energies of 7, 8, and $13\mathrm{\,Te\kern -0.1em V}$. Two peaking structures are seen with a local (global) significance of $4.3\,(2.8)$ and $4.1\,(2.4)$ standard deviations at masses of $6571\,\mathrm{Me\kern -0.1em V\!/}c^2$ and $6694\,\mathrm{Me\kern -0.1em V\!/}c^2$, respectively. Upper limits are set on the $\it{\Xi}_{bc}^{+}$ baryon production cross-section times the branching fraction relative to that of the $B_{c}^{+}\to J/\it{\psi} D_{s}^{+}$ decay at centre-of-mass energies of 8 and $13\mathrm{\,Te\kern -0.1em V}$, in the $\it{\Xi}_{bc}^{+}$ and in the $B_{c}^{+}$ rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to $20\,\mathrm{Ge\kern -0.1em V\!/}c$, respectively. Upper limits are presented as a function of the $\it{\Xi}_{bc}^{+}$ mass and lifetime.