Observation of the doubly charmed baryon decay ${\varXi}_{cc}^{++}\to {\varXi}_c^{\prime +}{\pi}^{+}$

Abstract

The ${\varXi}_{cc}^{++}\to {\varXi}_c^{\prime +}{\pi}^{+}$ decay is observed using proton-proton collisions collected by the LHCb experiment at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The ${\varXi}_{cc}^{++}\to {\varXi}_c^{\prime +}{\pi}^{+}$ decay is reconstructed partially, where the photon from the ${\varXi}_c^{\prime +}\to {\varXi}_c^{+}\gamma$ decay is not reconstructed and the pK⁻π⁺ final state of the ${\varXi}_c^{+}$ baryon is employed. The ${\varXi}_{cc}^{++}\to {\varXi}_c^{\prime +}{\pi}^{+}$branching fraction relative to that of the ${\varXi}_{cc}^{++}\to {\varXi}_c^{+}{\pi}^{+}$ decay is measured to be 1.41 ± 0.17 ± 0.10, where the first uncertainty is statistical and the second systematic.