Evidence for the singly-Cabibbo-suppressed decay ${\Lambda }_c^{+}\to p\eta$ and search for ${\Lambda }_c^{+}\to p{\pi }^0$

Abstract

We study the singly-Cabibbo-suppressed decays ${\Lambda }_c^{+}\to p\eta$ and ${\Lambda }_c^{+}\to p{\pi }^0$ using ${\Lambda }_c^{+}{\Lambda }_c^{+}$ pairs produced by $e^{+}{e}^{-}$ collisions at a center-of-mass energy of $\sqrt{s}=4.6GeV$. The data sample was collected by the BESIII detector at the BEPCII collider and corresponds to an integrated luminosity of 567 $p{b}^{-1}$. We find the first evidence for the decay ${\Lambda }_c^{+}\to p\eta$ with a statistical significance of $4.2\sigma$ and measure its branching fraction to be $\mathcal{B}({\Lambda }_c^{+}\to p\eta )=(1.24\pm 0.28(stat.)\pm 0.10(syst.))\times 10^{-3}$. No significant ${\Lambda }_c^{+}\to p{\pi }^0$ signal is observed. We set an upper limit on its branching fraction $\mathcal{B}({\Lambda }_c^{+}\to p{\pi }^0)<2.7\times 10^{-4}$ at the 90% confidence level.

7 pages, 2 figures