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

## TL;DR

This paper measures the branching ratio of the B$^+$ $ o$ J$/ar{mbda}$p decay in proton-proton collisions at 8 TeV, investigates invariant mass distributions, and finds evidence for excited kaon contributions.

## Contribution

It provides the first measurement of the branching ratio for this decay and performs an angular analysis revealing excited kaon states involved.

## Key findings

- Branching ratio measured as (1.054 ± 0.057 (stat) ± 0.035 (syst) ± 0.011 (B))%.
- Invariant mass distributions are inconsistent with pure phase space.
- Evidence suggests contributions from excited kaons decaying to mbda p.

## Abstract

A study of the B$^+$ $\to$ J$/\psi\overline{\Lambda}$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 $\mathcal{B}$(B$^+$ $\to$ J$/\psi\overline{\Lambda}$p ) / $\mathcal{B}$(B$^+$ $\to$ J$/\psi$K$^*$(892)$^+$) is measured to be (1.054 $\pm$ 0.057 (stat) $\pm$ 0.035 (syst) $\pm$ 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 J$/\psi\overline{\Lambda}$, J$/\psi$p, and $\overline{\Lambda}$p systems produced in the B$^+$ $\to$ J$/\psi\overline{\Lambda}$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 $\overline{\Lambda}$p system.