Transverse momentum dependent production cross sections of charged pions, kaons and protons produced in inclusive annihilation at 10.58 GeV

10.58GeVでの電子-陽電子対消滅反応におけるパイ中間子, K中間子,陽子生成の生成断面積の横運動量依存性

Seidl, R.*; 谷田 聖   ; Belle Collaboration*; 他186名*

Seidl, R.*; Tanida, Kiyoshi; Belle Collaboration*; 186 of others*

We report measurements of the production cross sections of charged pions, kaons, and protons as a function of fractional energy, the event-shape variable called thrust, and the transverse momentum with respect to the thrust axis. These measurements access the transverse momenta created in the fragmentation process, which are of critical importance to the understanding of any transverse momentum dependent distribution and fragmentation functions. The low transverse momentum part of the cross sections can be well described by Gaussians in transverse momentum as is generally assumed but the fractional-energy dependence is non-trivial and different hadron types have varying Gaussian widths. The width of these Gaussians decreases with thrust and shows an initially rising, then decreasing fractional-energy dependence. The widths for pions and kaons are comparable within uncertainties, while those for protons are significantly narrower. These single-hadron cross sections and Gaussian widths are obtained from a data sample collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider.