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)%.

Observation of Λ_c+→Λa0(980)+ and Evidence for Σ(1380)+ in Λc+→Λπ+\eta

Amoroso, A.;Bianchi, F.;Bortone, A.;Destefanis, M.;De Mori, F.;Greco, M.;Lavezzi, L.;Maggiora, M.;Marcello, S.;Sosio, S.;Spataro, S.;
2025-01-01

Abstract

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)%.
2025
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Ablikim, M.; Achasov, M. N.; Adlarson, P.; Afedulidis, O.; Ai, X. C.; Aliberti, R.; Amoroso, A.; An, Q.; Bai, Y.; Bakina, O.; Balossino, I.; Ban, Y.; ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/2069291
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