Measurement of the branching fractions of the singly Cabibbo-suppressed decays $$ {\Lambda}_{\textrm{c}}^{+}\to \textrm{p}\eta $$ and $$ {\Lambda}_{\textrm{c}}^{+}\to \textrm{p}\omega $$

Abstract

Based on 4.5 fb−1e+e− collision data collected with BESIII detector at seven energy points between 4.600 and 4.699 GeV, the branching fractions for $$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη and $$ {\Lambda}_c^{+}\to p\omega $$ Λ c + → pω were measured by means of single-tag method. The branching fractions of $$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη and $$ {\Lambda}_c^{+}\to p\omega $$ Λ c + → pω are determined to be (1.57 ± 0.11stat± 0.04syst) × 10−3 and (1.11 ± 0.20stat± 0.07syst) × 10−3, with a statistical significance of greater than 10σ and 5.7σ, respectively. These results are consistent with the previous measurements by BESIII, LHCb and Belle, and the result of $$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη is the most precise to date.

Observations of the Cabibbo-Suppressed decays , and the Cabibbo-Favored decay *

“…Evidence is obtained for the decay Λ + c → pπ 0 , with a statistical significance of 3.7σ and a decay BF of (1.56 +0.72 −0.58 ±0.20)×10 −4 . The BF of Λ + c → pη is measured as (1.63 ± 0.31 stat ± 0.11 syst ) × 10 −3 , consistent with previous results [3,4,28]. The B(Λ + c → pπ 0 ) result distinctly exceeds the upper limit measured by Belle experiment.…”

“…The systematic uncertainty from the ∆E requirement on the signal side is found to be 0.3% by studying the control samples of modes Λ + c → pK − π + π 0 and Λ + c → Λπ + π 0 . The uncertainty due to the signal MC model is taken as 0.4% [28]. Uncertainties from the BFs of η → γγ and π 0 → γγ are taken from PDG [19].…”