TY - JOUR
T1 - Observation of Λ+c → Λa0ð980Þ + and Evidence for Σð1380Þ + in Λ+c → Λπ + η
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Adlarson, P.
AU - Afedulidis, O.
AU - Ai, X. C.
AU - Aliberti, R.
AU - Amoroso, A.
AU - Kalantar-Nayestanaki, N.
AU - Kavatsyuk, M.
AU - Messchendorp, J.
PY - 2025/1/17
Y1 - 2025/1/17
N2 - Based on 6.1 fb-1 of e+e- annihilation data collected at center-of-mass energies from 4.600 to 4.843 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis of Λc+→Λπ+η is performed, and branching fractions and decay asymmetry parameters of intermediate processes are determined. The process Λc+→Λa0(980)+ is observed for the first time, and evidence for the pentaquark candidate ς(1380)+ decaying into Λπ+ is found with statistical significance larger than 3σ with mass and width fixed to theoretical predictions. The branching fraction product B[Λc+→Λa0(980)+]B[a0(980)+→π+η] is determined to be (1.05±0.16stat±0.05syst±0.07ext)%, which is larger than theoretical calculations by 1-2 orders of magnitude. Here the third (external) systematic is from B(Λc+→Λπ+η). Finally, we precisely obtain the absolute branching fraction B(Λc+→Λπ+η)=(1.94±0.07stat±0.11syst)%.
AB - Based on 6.1 fb-1 of e+e- annihilation data collected at center-of-mass energies from 4.600 to 4.843 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis of Λc+→Λπ+η is performed, and branching fractions and decay asymmetry parameters of intermediate processes are determined. The process Λc+→Λa0(980)+ is observed for the first time, and evidence for the pentaquark candidate ς(1380)+ decaying into Λπ+ is found with statistical significance larger than 3σ with mass and width fixed to theoretical predictions. The branching fraction product B[Λc+→Λa0(980)+]B[a0(980)+→π+η] is determined to be (1.05±0.16stat±0.05syst±0.07ext)%, which is larger than theoretical calculations by 1-2 orders of magnitude. Here the third (external) systematic is from B(Λc+→Λπ+η). Finally, we precisely obtain the absolute branching fraction B(Λc+→Λπ+η)=(1.94±0.07stat±0.11syst)%.
U2 - 10.1103/PhysRevLett.134.021901
DO - 10.1103/PhysRevLett.134.021901
M3 - Article
SN - 0031-9007
VL - 134
JO - Physical Review Letters
JF - Physical Review Letters
IS - 2
M1 - 021901
ER -