@article{21014f7d343c492e8757089595e209e0,
title = "Observation of the Radiative Decays of ψ (1S) to χc1",
abstract = "We report the first observation of the radiative decay of the ψ(1S) into a charmonium state. The significance of the observed signal of ψ(1S)→γχc1 is 6.3 standard deviations including systematics. The branching fraction is calculated to be B[ψ(1S)→γχc1]=[4.7-1.8+2.4(stat)-0.5+0.4(sys)×10-5]. We also searched for ψ(1S) radiative decays into χc0,2 and ηc(1S,2S), and set upper limits on their branching fractions. These results are obtained from a 24.9 fb-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at a center-of-mass energy equal to the ψ(2S) mass using ψ(1S) tagging by the ψ(2S)→ψ(1S)π+π- transitions.",
author = "{Belle Collaboration} and P. Katrenko and I. Adachi and H. Aihara and {Al Said}, S. and Asner, {D. M.} and T. Aushev and I. Badhrees and S. Bahinipati and P. Behera and C. Bele{\~n}o and J. Bennett and V. Bhardwaj and B. Bhuyan and J. Biswal and A. Bobrov and G. Bonvicini and M. Bra{\v c}ko and M. Campajola and L. Cao and D. {\v C}ervenkov and V. Chekelian and A. Chen and Cheon, {B. G.} and K. Chilikin and Cho, {H. E.} and K. Cho and Choi, {S. K.} and Y. Choi and S. Choudhury and D. Cinabro and S. Cunliffe and {Di Capua}, F. and {Di Carlo}, S. and Z. Dole{\v Z}al and Dong, {T. V.} and S. Eidelman and D. Epifanov and Fast, {J. E.} and Fulsom, {B. G.} and R. Garg and V. Gaur and N. Gabyshev and A. Garmash and A. Giri and P. Goldenzweig and B. Golob and O. Grzymkowska and O. Hartbrich and K. Hayasaka and H. Park",
note = "Publisher Copyright: {\textcopyright} 2020 authors. Published by the American Physical Society.",
year = "2020",
month = mar,
day = "27",
doi = "10.1103/PhysRevLett.124.122001",
language = "English",
volume = "124",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "12",
}