TY - JOUR

T1 - Observation of Ds+→η′μ+νμ, Precision Test of Lepton Flavor Universality with Ds+→η(′)l+νl, and First Measurements of Ds+→η(′)μ+νμ Decay Dynamics

AU - BESIII Collaboration

AU - Ablikim, M.

AU - Achasov, M. n.

AU - Николаев, Иван Борисович

AU - Мучной, Николай Юрьевич

PY - 2024/2/28

Y1 - 2024/2/28

N2 - By analyzing 7.33 fb-1 of e+e- annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay Ds+→η′μ+νμ, with a statistical significance larger than 10σ, and the measurements of the Ds+→ημ+νμ and Ds+→η′μ+νμ decay dynamics for the first time. The branching fractions of Ds+→ημ+νμ and Ds+→η′μ+νμ are determined to be (2.235±0.051stat±0.052syst)% and (0.801±0.055stat±0.028syst)%, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays Ds+→ηe+νe and Ds+→η′e+νe, the ratios of the decay widths are examined both inclusively and in several ℓ+νℓ four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors f+,0η(′)(0) and the c→s Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined. The results based on the two-parameter series expansion are f+,0η(0)|Vcs|=0.452±0.010stat±0.007syst and f+,0η′(0)|Vcs|=0.504±0.037stat±0.012syst, which help to constrain present models on f+,0η(′)(0). The forward-backward asymmetries are determined to be (AFBη)=-0.059±0.031stat±0.005syst and (AFBη′)=-0.064±0.079stat±0.006syst for the first time, which are consistent with the theoretical calculation.

AB - By analyzing 7.33 fb-1 of e+e- annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay Ds+→η′μ+νμ, with a statistical significance larger than 10σ, and the measurements of the Ds+→ημ+νμ and Ds+→η′μ+νμ decay dynamics for the first time. The branching fractions of Ds+→ημ+νμ and Ds+→η′μ+νμ are determined to be (2.235±0.051stat±0.052syst)% and (0.801±0.055stat±0.028syst)%, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays Ds+→ηe+νe and Ds+→η′e+νe, the ratios of the decay widths are examined both inclusively and in several ℓ+νℓ four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors f+,0η(′)(0) and the c→s Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined. The results based on the two-parameter series expansion are f+,0η(0)|Vcs|=0.452±0.010stat±0.007syst and f+,0η′(0)|Vcs|=0.504±0.037stat±0.012syst, which help to constrain present models on f+,0η(′)(0). The forward-backward asymmetries are determined to be (AFBη)=-0.059±0.031stat±0.005syst and (AFBη′)=-0.064±0.079stat±0.006syst for the first time, which are consistent with the theoretical calculation.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85186268587&origin=inward&txGid=c2509fc1492f73f7581f682dc11a0aff

UR - https://pubmed.ncbi.nlm.nih.gov/38489649/

U2 - 10.1103/PhysRevLett.132.091802

DO - 10.1103/PhysRevLett.132.091802

M3 - Article

C2 - 38489649

VL - 132

SP - 091802

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 9

M1 - 091802

ER -