Measurements of the branching fractions of ${\Lambda }_c^{+}\to p\eta$ and ${\Lambda }_c^{+}\to p{\pi }^0$ decays at Belle

Abstract

We report measurements of the branching fractions of singly Cabibbo-suppressed decays ${\Lambda }_c^{+}\to p\eta$ and ${\Lambda }_c^{+}\to p{\pi }^0$ using the full Belle data sample corresponding to an integrated luminosity of 980.6 $\mathrm{f}{\mathrm{b}}^{-1}$. The data were collected by the Belle detector at the KEKB $e^{+}$$e^{-}$ asymmetric-energy collider. A clear ${\Lambda }_c^{+}$ signal is seen in the invariant mass distribution of $p\eta$. The signal yield of the ${\Lambda }_c^{+}\to p\eta$ process is $7734\pm 263$; from this, we measure the ratio of branching fractions $\mathcal{B}({\Lambda }_c^{+}\to p\eta )/\mathcal{B}({\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+})=(2.258\pm 0.077(stat.)\pm 0.136(syst.))\times 10^{-2}$, from which we infer the branching fraction $\mathcal{B}({\Lambda }_c^{+}\to p\eta )=(1.42\pm 0.05(stat.)\pm 0.11(syst.))\times 10^{-3}$. In addition, no significant signal for ${\Lambda }_c^{+}\to p{\pi }^0$ is found so an upper limit on the branching fraction of $\mathcal{B}({\Lambda }_c^{+}\to p{\pi }^0)<8.0\times 10^{-5}$ at 90\% credibility level is set, more than three times better than the best current upper limit.

Comments: 9 pages, 7 figures, accepted for publication as a Regular Article in Physical Review D