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

Abstract

Abstract

A study of the B+→J/ψΛ¯p$$ {\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\Lambda}\mathrm{p} $$ decay using proton-proton collision data collected at s$$ \sqrt{s} $$ = 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 BB+→J/ψΛ¯p/BB+→J/ψK∗892+$$ \mathcal{B}\left({\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\Lambda}\mathrm{p}\right)/\mathcal{B}\left({\mathrm{B}}^{+}\to \mathrm{J}/{\uppsi \mathrm{K}}^{\ast }{(892)}^{+}\right) $$ is measured to be (1.054 ± 0.057(stat) ± 0.035(syst) ± 0.011(B$$ \mathcal{B} $$))%, where the last uncertainty reflects the uncertainties in the world-average branching fractions of Λ¯$$ \overline{\Lambda} $$ and K*(892) + decays to reconstructed final states. The invariant mass distributions of the J/ψΛ¯$$ \mathrm{J}/\uppsi \overline{\Lambda} $$, J/ψp, and Λ¯p$$ \overline{\Lambda}\mathrm{p} $$ systems produced in the B+→J/ψΛ¯p$$ {\mathrm{B}}^{+}\to \mathrm{J}/\uppsi \overline{\varLambda}\mathrm{p} $$ 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 Λ¯p$$ \overline{\Lambda}\mathrm{p} $$ system.