# Observation of the doubly Cabibbo-suppressed decay $\Xi_{c}^{+}\to p\phi$

## TL;DR

This paper reports the first observation of the doubly Cabibbo-suppressed decay ^{+} o p with high statistical significance, measuring its branching ratio relative to a known decay mode using LHCb data at 8 TeV.

## Contribution

It provides the first experimental observation and measurement of the decay ^{+} o p, expanding understanding of charm baryon decay processes.

## Key findings

- First observation of ^{+} o p decay with >15 sigma significance.
- Measured branching ratio relative to ^{+} o pK^{-}^{+} decay.
- Quantified uncertainties including statistical, systematic, and  decay branching fraction.

## Abstract

The doubly Cabibbo-suppressed decay $\Xi_{c}^{+}\to p\phi$ with $\phi\to K^{+}K^{-}$ is observed for the first time, with a statistical significance of more than fifteen standard deviations. The data sample used in this analysis corresponds to an integrated luminosity of 2 fb$^{-1}$ recorded with the LHCb detector in $pp$ collisions at a centre-of-mass energy of 8 TeV. The ratio of branching fractions between the decay $\Xi_{c}^{+}\to p\phi$ and the singly Cabibbo-suppressed decay $\Xi_{c}^{+}\to pK^{-}\pi^{+}$ is measured to be \begin{equation*} \frac{\mathcal{B}(\Xi_{c}^{+}\to p\phi)}{\mathcal{B}(\Xi_{c}^{+}\to pK^{-}\pi^{+})} = (19.8 \pm 0.7 \pm 0.9 \pm 0.2) \times 10^{-3}, \end{equation*} where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the $\phi\to K^{+}K^{-}$ branching fraction.