Measurements of the branching fractions of λc+ →pη and λc+ →pπ0 decays at belle.

Abstract

We report measurements of the branching fractions of singly Cabibbo-suppressed decays Λþ c → pη and Λþ c → pπ0 using the full Belle data sample corresponding to an integrated luminosity of 980.6 fb−1. The data were collected by the Belle detector at the KEKB eþe− asymmetric energy collider. A clear Λþ c signal is seen in the invariant mass distribution of pη. The fitted number of signal events of the Λþ c → pη process is 7734 263; from this, we measure the ratio of branching fractions BðΛþ c → pηÞ=BðΛþ c → pK−πþÞ ¼ ½2.258 0.077ðstatÞ 0.122ðsystÞ × 10−2, from which we infer the branching fraction BðΛþ c → pηÞ ¼ ½1.42 0.05ðstatÞ 0.11ðsystÞ × 10−3. In addition, no significant signal for Λþ c → pπ0 is found, so an upper limit on the branching fraction of BðΛþ c → pπ0Þ < 8.0 × 10−5 at a 90% credibility level is set, more than 3 times better than the best current upper limit.