Inclusive cross sections for pairs of identified light charged hadrons and for single protons in e(+)e(-) at root s=10.58 GeV
Abstract
We report the first double differential cross sections of two charged pions and kaons (e(+)e(-) -> hhX) in electron-positron annihilation as a function of the fractional energies of the two hadrons for any charge and hadron combination. The dependence of these dihadron cross sections on the topology (same, opposite hemisphere or anywhere) is also studied with the help of the event shape variable thrust and its axis.
The ratios of these dihadron cross sections for different charges and hadron combinations directly shed light on the contributing fragmentation functions. For example, we find that the ratio of same-sign pion pairs over opposite-sign pion pairs drops toward higher fractional energies where disfavored fragmentation is expected to be suppressed.
These dihadron results are obtained from a 655 fb(-1) data sample collected near the gamma (4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. Extending the previously published single-pion and single-kaon cross sections, single-proton (e(+)e(-) -> pX) cross sections are extracted from a 159 fb(-1) data subsample.