Study of the $$ {\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\Lambda}\mathrm{p} $$decay in proton-proton collisions at $$ \sqrt{s} $$= 8 TeV

A study of the $$ {\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\Lambda}\mathrm{p} $$decay using proton-proton collision data collected at $$ \sqrt{s} $$= 8 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fb−1, is presented. The ratio of branching fractions $$ \mathcal{B}\left({\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\Lambda}\mathrm{p}\right)/\mathcal{B}\left({\mathrm{B}}^{+}\to \mathrm{J}/{\uppsi \mathrm{K}}^{\ast }{(892)}^{+}\right) $$is measured to be (1.054 ± 0.057(stat) ± 0.035(syst) ± 0.011($$ \mathcal{B} $$))%, where the last uncertainty reflects the uncertainties in the world-average branching fractions of $$ \overline{\Lambda} $$and K*(892) + decays to reconstructed final states. The invariant mass distributions of the $$ \mathrm{J}/\uppsi \overline{\Lambda} $$, J/ψp, and $$ \overline{\Lambda}\mathrm{p} $$systems produced in the $$ {\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\varLambda}\mathrm{p} $$decay are investigated and found to be inconsistent with the pure phase space hypothesis. The analysis is extended by using a model-independent angular amplitude analysis, which shows that the observed invariant mass distributions are consistent with the contributions from excited kaons decaying to the $$ \overline{\Lambda}\mathrm{p} $$system.