High-statistics study of {eta}{pi}{sup 0} production in two-photon collisions

Journal Article · Sat Aug 01 00:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.032001· OSTI ID:21322315

Uehara, S; Adachi, I; Dalseno, J; Itoh, R; Iwasaki, Y; Kichimi, H; Krokovny, P; Nakao, M; Nishida, S; Sakai, Y; Uno, S ^[1]; Watanabe, Y; Okuno, S ^[2]; Nakazawa, H; Chen, A ^[3]; Aihara, H; Iwasaki, M ^[4]; Arinstein, K; Aulchenko, V; Bondar, A ^[5]

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1. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
2. Kanagawa University, Yokohama (Japan)
3. National Central University, Chung-li (China)
4. Department of Physics, University of Tokyo, Tokyo (Japan)
5. Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

The differential cross section for the process {gamma}{gamma}{yields}{eta}{pi}{sup 0} has been measured in the kinematic range 0.84 GeV<W<4.0 GeV, |cos{theta}*|<0.8, where W and {theta}* are the energy and {pi}{sup 0} (or {eta}) scattering angle, respectively, in the {gamma}{gamma} center-of-mass system. The results are based on a 223 fb{sup -1} data sample collected with the Belle detector at the KEKB e{sup +}e{sup -} collider. Clear peaks due to the a{sub 0}(980) and a{sub 2}(1320) are visible. The differential cross sections are fitted in the energy region 0.9 GeV<W<1.46 GeV to obtain the parameters of the a{sub 0}(980). Its mass, width and {gamma}{sub {gamma}}{sub {gamma}}B({eta}{pi}{sup 0}) are measured to be 982.3{sub -0.7-4.7}{sup +0.6+3.1} MeV/c{sup 2}, 75.6{+-}1.6{sub -10.0}{sup +17.4} MeV and 128{sub -2-43}{sup +3+502} eV, respectively. The energy and angular dependences above 3.1 GeV are compared with those measured in the {pi}{sup 0}{pi}{sup 0} channel. The integrated cross section over |cos{theta}*|<0.8 has a W{sup -n} dependence with n=10.5{+-}1.2{+-}0.5, which is slightly larger than that for {pi}{sup 0}{pi}{sup 0}. The differential cross sections show a sin{sup -4}{theta}* dependence similar to {gamma}{gamma}{yields}{pi}{sup 0}{pi}{sup 0}. The measured cross section ratio, {sigma}({eta}{pi}{sup 0})/{sigma}({pi}{sup 0}{pi}{sup 0})=0.48{+-}0.05{+-}0.04, is consistent with a QCD-based prediction.

• OSTI ID: 21322315
• Journal Information: Physical Review. D, Particles Fields, Vol. 80, Issue 3; Other Information: DOI: 10.1103/PhysRevD.80.032001; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
A0-980 MESONS
A2-1320 MESONS
CENTER-OF-MASS SYSTEM
DIFFERENTIAL CROSS SECTIONS
ELECTRON-POSITRON COLLISIONS
ETA MESONS
FORECASTING
GAMMA RADIATION
GEV RANGE 01-10
KEK LINAC
MASS
PHOTON COLLISIONS
PIONS NEUTRAL
POSITRONS
QUANTUM CHROMODYNAMICS
SCATTERING