TY - JOUR

T1 - Observation of D+→KS0π0μ+νμ, Test of Lepton Flavor Universality, and First Angular Analysis of D+ → K ¯∗(892)0ℓ+νℓ

AU - BESIII Collaboration

AU - Ачасов, Михаил Николаевич

AU - Мучной, Николай Юрьевич

AU - Николаев, Иван Борисович

N1 - The BESIII Collaboration thanks the staff of BEPCII [69] 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. 2023YFA1606000, No. 2023YFA1606704; National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, 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; CAS under Contract No. YSBR-101; 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; Agencia Nacional de Investigación y Desarrollo de Chile (ANID), Chile under Contract No. ANID PIA/APOYO AFB230003; German Research Foundation DFG under Contract No. FOR5327; Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation under Contracts No. 2021.0174, No. 2021.0299; 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 & Institutional Development, Research and Innovation of Thailand under Contract No. B50G670107; Polish National Science Centre under Contract No. 2024/53/B/ST2/00975; Swedish Research Council under Contract No. 2019.04595; U.S. Department of Energy under Contract No. DE-FG02-05ER41374.

PY - 2025/10/21

Y1 - 2025/10/21

N2 - We report a study of the semileptonic decays 퐷+→퐾0푆⁢휋0⁢ℓ+⁢휈ℓ (ℓ =푒, 휇) based on 20.3  fb−1 of 푒+⁢푒− collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The 퐷+→퐾0푆⁢휋0⁢휇+⁢휈휇 decay is observed for the first time, with a branching fraction of (0.896±0.01⁢7stat±0.00⁢8syst)%, and the branching fraction of 퐷+→퐾0푆⁢휋0⁢푒+⁢휈푒 is determined with the improved precision as (0.943±0.01⁢2stat±0.01⁢0syst)%. From the analysis of the dynamics, we observe that the dominant ¯퐾*⁢(892)0 component is accompanied by an 푆-wave contribution, which accounts for (7.10±0.6⁢8stat±0.4⁢1syst)% of the total decay rate of the 휇+ channel and (6.39±0.1⁢7stat±0.1⁢4syst)% of the 푒+ channel. Assuming a single-pole dominance parametrization, the hadronic form factor ratios are extracted to be 푟푉=푉⁡(0)/퐴1⁡(0)=1.42±0.0⁢3stat±0.0⁢2syst and 푟2=퐴2⁡(0)/퐴1⁡(0)=0.75±0.0⁢3stat±0.0⁢1syst. Based on the first comprehensive angular and the decay-rate 퐶⁢푃 asymmetry analysis, the full set of averaged angular and 퐶⁢푃 asymmetry observables are measured as a function of the momentum-transfer squared; they are consistent with expectations from the standard model. No evidence for violation of 휇 −푒 lepton-flavor universality is observed in either the full range or the five chosen bins of momentum-transfer squared.

AB - We report a study of the semileptonic decays 퐷+→퐾0푆⁢휋0⁢ℓ+⁢휈ℓ (ℓ =푒, 휇) based on 20.3  fb−1 of 푒+⁢푒− collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The 퐷+→퐾0푆⁢휋0⁢휇+⁢휈휇 decay is observed for the first time, with a branching fraction of (0.896±0.01⁢7stat±0.00⁢8syst)%, and the branching fraction of 퐷+→퐾0푆⁢휋0⁢푒+⁢휈푒 is determined with the improved precision as (0.943±0.01⁢2stat±0.01⁢0syst)%. From the analysis of the dynamics, we observe that the dominant ¯퐾*⁢(892)0 component is accompanied by an 푆-wave contribution, which accounts for (7.10±0.6⁢8stat±0.4⁢1syst)% of the total decay rate of the 휇+ channel and (6.39±0.1⁢7stat±0.1⁢4syst)% of the 푒+ channel. Assuming a single-pole dominance parametrization, the hadronic form factor ratios are extracted to be 푟푉=푉⁡(0)/퐴1⁡(0)=1.42±0.0⁢3stat±0.0⁢2syst and 푟2=퐴2⁡(0)/퐴1⁡(0)=0.75±0.0⁢3stat±0.0⁢1syst. Based on the first comprehensive angular and the decay-rate 퐶⁢푃 asymmetry analysis, the full set of averaged angular and 퐶⁢푃 asymmetry observables are measured as a function of the momentum-transfer squared; they are consistent with expectations from the standard model. No evidence for violation of 휇 −푒 lepton-flavor universality is observed in either the full range or the five chosen bins of momentum-transfer squared.

UR - https://www.scopus.com/pages/publications/105021200680

U2 - 10.1103/w9vz-4fq9

DO - 10.1103/w9vz-4fq9

M3 - Article

VL - 135

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 17

M1 - 171801

ER -