Электронный каталог

Статья

Ablikim, M.
Improved Measurements of the Dalitz Decays *h/*h' *> *ge*+e*- / M.Ablikim, O.Bakina, I.Boyko, G.Chelkov, D.Dedovich, I.Denysenko, P.Egorov, A.Guskov, Y.Nefedov, A.Sarantsev, A.Zhemchugov, [a.o.] // Physical Review D [Electronic resource]. – 2024. – Vol. 109, No. 7. – P. 072001. – URL: https://doi.org/10.1103/PhysRevD.109.072001. – Bibliogr.: 48.

Based on a data sample of 10 billion J/ψ events collected with the BESIII detector, improved measurements of the Dalitz decays η/η'0 → γe*+e*− are performed, where the η and η' are produced through the radiative decays J/ψ → γη/η' . The branching fractions of η → γe*+e*− and η' → γe*+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 η → γe*+e*− is determined to be Λη =(0.749 *( 0.027 *( 0.007) GeV=c*2. Within the multipole model, we extract the electromagnetic transition form factors for η' → γe*+e*− to be Λ&sub(*h')= (0.802 *( 0.007 *( 0.008) GeV=c*2 and γ&sub(*h')=(0.113 *( 0.010 *( 0.002)GeV/c*2. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the η and η' 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 η/η' → γe*+e*−, and the upper limits of the branching fractions as a function of the dark photon are given at 90% confidence level.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 332.7 - Встречные е+е- и мю+мю- пучки