A high precision study of the process γγ→pp̄ has been performed using a data sample of 89 fb-1 collected with the Belle detector at the KEKB e+e- collider. The cross section of pp̄ production has been measured at two-photon center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in the c.m. angular range of |cosθ*|<0.6. Production of γγ→ηc→pp̄ is observed and the product of the two-photon width of the ηc and its branching ratio to pp̄ is determined.
|Number of pages||15|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2005 Aug 11|
Bibliographical noteFunding Information:
We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group and the NII for valuable computing and Super-SINET network support. We thank C.F. Berger, V.L. Chernyak, H.-N. Li and K. Odagiri for fruitful discussions. We acknowledge support from MEXT and JSPS (Japan); ARC and DEST (Australia); NSFC (contract No. 10175071, China); DST (India); the BK21 program of MOEHRD and the CHEP SRC program of KOSEF (Korea); KBN (contract No. 2P03B 01324, Poland); MIST (Russia); MESS (Slovenia); SNSF (Switzerland); NSC (under Grant No. NSC-92-2112-M-008-028) and MOE (Taiwan); and DOE (USA).
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics