Monte Carlo results on the Collins asymmetries in $e^+e^-$ annihilation

A. Kerbizi; L. Lönnblad; A. Martin

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arXiv · 2410.11489

Monte Carlo results on the Collins asymmetries in $e^+e^-$ annihilation

A. Kerbizi·L. Lönnblad·A. Martin

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Abstract

The quark spin effects have been introduced in the Pythia 8 Monte Carlo event generator for the simulation of $e^+e^-$ annihilation by interfacing the generator with the StringSpinner package. The package allows to simulate quark spin effects in the string fragmentation routine of Pythia by using the string+${}^3P_0$ model, recently applied to the fragmentation of a string stretched between a quark-antiquark pair with correlated spin states. StringSpinner is used to carry out simulations of $e^+e^-$ annihilation at the center of mass energy of $10.6\,\rm{GeV}$. The Collins asymmetries are extracted from the simulated data for back-to-back pion pairs using both the thrust axis method and the hadronic plane method. The results are compared with the data from the BELLE and BABAR experiments, finding a satisfactory agreement.

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A. Kerbizi, L. Lönnblad, A. Martin. 2024-10-15. Monte Carlo results on the Collins asymmetries in $e^+e^-$ annihilation. https://arxiv.org/abs/2410.11489

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