TY - JOUR

T1 - Observation of the singly Cabibbo-suppressed decay Λc+→pπ0

AU - BESIII Collaboration

AU - Ablikim, M.

AU - Achasov, M. n.

AU - Николаев, Иван Борисович

AU - Мучной, Николай Юрьевич

N1 - The authors thank Huilin Qu, Congqiao Li, and Sitian Qian for suggestions on deep learning. 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. 11935015, No. 11935016, No. 11935018, 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, No. 12361141819; 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; 100 Talents Program of CAS; CAS Project for Young Scientists in Basic Research No. YSBR-117; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG under Contracts No. 455635585, 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. Observation of the singly Cabibbo-suppressed decay Λc+→pπ0 / The BESIII Collaboration // Physical Review D. – 2025. – Vol. 111, No. 5. – P. L051101. – DOI 10.1103/physrevd.111.L051101.

PY - 2025/3/14

Y1 - 2025/3/14

N2 - Utilizing 4.5 fb-1 of e+e- annihilation data collected with the BESIII detector at the BEPCII collider at center-of-mass energies between 4.600 and 4.699 GeV, the first observation of the singly Cabibbo-suppressed decay Λc+→pπ0 is presented, with a statistical significance of 5.4σ. The ratio of the branching fractions of Λc+→pπ0 and Λc+→pη is measured as B(Λc+→pπ0)/B(Λc+→pη)=(0.120±0.026stat±0.007syst). This result resolves the longstanding discrepancy between earlier experimental searches, providing both a decisive conclusion and valuable input for QCD-inspired theoretical models. A sophisticated deep learning approach using a Transformer-based architecture is employed to distinguish the signal from the prevalent hadronic backgrounds, complemented by thorough validation and systematic uncertainty quantification.

AB - Utilizing 4.5 fb-1 of e+e- annihilation data collected with the BESIII detector at the BEPCII collider at center-of-mass energies between 4.600 and 4.699 GeV, the first observation of the singly Cabibbo-suppressed decay Λc+→pπ0 is presented, with a statistical significance of 5.4σ. The ratio of the branching fractions of Λc+→pπ0 and Λc+→pη is measured as B(Λc+→pπ0)/B(Λc+→pη)=(0.120±0.026stat±0.007syst). This result resolves the longstanding discrepancy between earlier experimental searches, providing both a decisive conclusion and valuable input for QCD-inspired theoretical models. A sophisticated deep learning approach using a Transformer-based architecture is employed to distinguish the signal from the prevalent hadronic backgrounds, complemented by thorough validation and systematic uncertainty quantification.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-105000965124&origin=inward&txGid=56b76dc9e8672238ead77fab312c67c6

UR - https://www.mendeley.com/catalogue/e7572681-d291-3603-a87a-70602477a5ec/

U2 - 10.1103/PhysRevD.111.L051101

DO - 10.1103/PhysRevD.111.L051101

M3 - Article

VL - 111

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 5

M1 - L051101

ER -