Invariant-mass and fractional-energy dependence of inclusive production of dihadrons in e + e − annihilation at √s = 10.58 GeV

Abstract

The inclusive cross sections for di-hadrons of charged pions and kaons (e+e−→hhX) in electron-positron annihilation are reported. They are obtained as a function of the total fractional energy and invariant mass for any di-hadron combination in the same hemisphere as defined by the thrust event-shape variable and its axis. Since same-hemisphere di-hadrons can be assumed to originate predominantly from the same initial parton, di-hadron fragmentation functions are probed. These di-hadron fragmentation functions are needed as an unpolarized baseline in order to quantitatively understand related spin-dependent measurements in other processes and to apply them to the extraction of quark transversity distribution functions in the nucleon. The di-hadron cross sections are obtained from a 655fb−1 data sample collected at or near the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider.