We have measured π+π- and K+K - production in two-photon collisions using 87.7fb-1 of data collected with the Belle detector at the asymmetric energy e +e- collider KEKB. The cross sections are measured to high precision in the two-photon center-of-mass energy (W) range between 2.4GeV<W<4.1GeV and angular region |cosθ*|<0.6. The cross section ratio σ(γγ→K+K-)/ σ(γγ→π+π-) is measured to be 0.89±0.04(stat.)±0.15(syst.) in the range of 3.0GeV<W<4. 1GeV, where the ratio is energy-independent. We observe a sin -4θ* behavior of the cross section in the same W range. Production of χc0 and χc2 mesons is observed in both γγ→π+π- and γγ→K+K- modes.
|Number of pages||11|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - 26 May 2005|
- Two-photon collisions