TY - JOUR

T1 - Observation of Λc+→Λa0(980)+ and Evidence for Σ(1380)+ n Λc+→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 - An, Q.

AU - Bai, Y.

AU - Bakina, O.

AU - Balossino, I.

AU - Ban, Y.

AU - Bao, H.-R.

AU - Batozskaya, V.

AU - Begzsuren, K.

AU - Berger, N.

AU - Berlowski, M.

AU - Bertani, M.

AU - Bettoni, D.

AU - Bianchi, F.

AU - Bianco, E.

AU - Bortone, A.

AU - Boyko, I.

AU - Briere, R. a.

AU - Brueggemann, A.

AU - Cai, H.

AU - Cai, X.

AU - Мучной, Николай Юрьевич

AU - Николаев, Иван Борисович

N1 - We thank En Wang, Guan-Ying Wang, Yu-Kuo Hsiao, and Jia-Jun Wu for useful discussions. The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key R&D Program of China under Contracts No. 2020YFA0406400, No. 2020YFA0406300, No. 2023YFA1606000; National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, No. 11735014, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012, No. 12025502, No. 12035009, No. 12035013, No. 12061131003, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, No. 12192265, No. 12221005, No. 12225509, No. 12235017; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contract No. U1832207; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003, No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; European Union’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant agreement under Contract No. 894790; German Research Foundation DFG under Contracts No. 455635585, Collaborative Research Center CRC 1044, No. FOR5327, No. GRK 2149; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Research Foundation of Korea under Contract No. NRF-2022R1A2C1092335; National Science and Technology fund of Mongolia; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources and Institutional Development, Research and Innovation of Thailand under Contract No. B16F640076; Polish National Science Centre under Contract No. 2019/35/O/ST2/02907; The Swedish Research Council; U.S. Department of Energy under Contract No. DE-FG02-05ER41374.

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)%.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85215947894&origin=inward&txGid=8e2e27a37eaf80e661f7c31a42bcab8f

U2 - 10.1103/PhysRevLett.134.021901

DO - 10.1103/PhysRevLett.134.021901

M3 - Article

VL - 134

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 2

M1 - 021901

ER -