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

Abstract

The inclusive cross sections for dihadrons of charged pions and kaons (e+e- → hhX) in electronpositronannihilation are reported. They are obtained as a function of the total fractional energy andinvariant mass for any di-hadron combination in the same hemisphere as defined by the thrust event-shapevariable and its axis. Since same-hemisphere dihadrons can be assumed to originate predominantly fromthe same initial parton, di-hadron fragmentation functions are probed. These di-hadron fragmentationfunctions are needed as an unpolarized baseline in order to quantitatively understand related spindependentmeasurements in other processes and to apply them to the extraction of quark transversitydistribution functions in the nucleon. The di-hadron cross sections are obtained from a 655 fb^−1 datasample collected at or near the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.