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تسجيل مستخدم جديدInclusive cross sections for pairs of identified light charged hadrons and for single protons in $e^+e^-$ at $sqrt{s}=$ 10.58 GeV
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We report the first double differential cross sections of two charged pions and kaons ($e^+e^- rightarrow hhX$) 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 di-hadron 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 di-hadron 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 di-hadron results are obtained from a $655,{rm fb}^{-1}$ data sample collected near the $Upsilon(4S)$ 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 ($e^+e^- rightarrow pX$) cross sections are extracted from a $159,{rm fb}^{-1}$ data sub-sample.
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