Journal article
Observation of new resonant structures in γγ→ω, , and ωω
ZQ Liu, CP Shen, CZ Yuan, T Iijima, I Adachi, H Aihara, DM Asner, V Aulchenko, T Aushev, AM Bakich, K Belous, V Bhardwaj, B Bhuyan, M Bischofberger, A Bondar, A Bozek, M Bračko, TE Browder, MC Chang, P Chang Show all
Physical Review Letters | Published : 2012
Abstract
The processes γγ→ω, , and ωω are measured using an 870fb -1 data sample collected with the Belle detector at the KEKB asymmetric-energy e +e - collider. Production of vector meson pairs is clearly observed and their cross sections are measured for masses that range from threshold to 4.0 GeV. In addition to signals from well established spin-zero and spin-two charmonium states, there are resonant structures below charmonium threshold, which have not been previously observed. We report a spin-parity analysis for the new structures and determine the products of the η c, χ c0, and χ c2 two-photon decay widths and branching fractions to ω, , and ωω. © 2012 American Physical Society.
Grants
Funding Acknowledgements
We thank the KEKB group for excellent operation of the accelerator; the KEK cryogenics group for efficient solenoid operations; and the KEK computer group, the NII, and PNNL/EMSL for valuable computing and SINET4 network support. We acknowledge support from MEXT, JSPS and Nagoya's TLPRC (Japan); ARC and DIISR (Australia); NSFC (China); MSMT (Czechia); DST (India); INFN (Italy); MEST, NRF, GSDC of KISTI, and WCU (Korea); MNiSW (Poland); MES and RFAAE (Russia); ARRS (Slovenia); SNSF (Switzerland); NSC and MOE (Taiwan); and DOE and NSF (USA).