Improved measurements of the Dalitz decays ?/?? ??e+e-
Küçük Resim Yok
Tarih
2024
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
American Physical Society
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Based on a data sample of 10 billion J/? events collected with the BESIII detector, improved measurements of the Dalitz decays ?/????e+e- are performed, where the ? and ?? are produced through the radiative decays J/????/??. The branching fractions of ???e+e- and ????e+e- are measured to be (7.07±0.05±0.23)×10-3 and (4.83±0.07±0.14)×10-4, respectively. Within the single-pole model, the parameter of electromagnetic transition form factor for ???e+e- is determined to be ??=(0.749±0.027±0.007) GeV/c2. Within the multipole model, we extract the electromagnetic transition form factors for ????e+e- to be ???=(0.802±0.007±0.008) GeV/c2 and ???=(0.113±0.010±0.002) GeV/c2. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the ? and ?? are calculated to be (0.645±0.023±0.007) fm and (0.596±0.005±0.006) fm, respectively. In addition, we search for the dark photon in ?/????e+e-, and the upper limits of the branching fractions as a function of the dark photon are given at 90% confidence level. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Açıklama
Anahtar Kelimeler
Kaynak
Physical Review D
WoS Q Değeri
Scopus Q Değeri
Q1
Cilt
109
Sayı
7
