Single Inclusive $\pi^\pm$ and $K^\pm$ Production in $e^+e^-$ Annihilation at center-of-mass Energies from 2.000 to 3.671GeV

TL;DR

This study measures the production rates of charged pions and kaons in electron-positron collisions at energies from 2 to 3.7 GeV, providing data that support QCD predictions and isospin symmetry in fragmentation.

Contribution

First measurement of inclusive $ m \pi^\pm$ and $ m K^\pm$ cross sections at these energies, confirming QCD predictions and isospin symmetry in parton fragmentation.

Findings

$ m \pi^\pm$ cross sections agree with $ m \pi^0$ results

$ m K^\pm$ cross sections are 1.4 times higher than $ m K^0_S$

Results align with NNLO QCD analyses at low energies

Abstract

Using data samples with a total integrated luminosity of 253 $\rm pb^{-1}$ collected by the BESIII detector operating at the BEPCII collider, the differential cross-sections of inclusive $\pi^\pm$ and $K^\pm$ production, as a function of momentum and normalized by the total hadronic cross-section, are measured at center-of-mass energies from 2.000 to 3.671 GeV. The measured $\pi^{\pm}$ cross sections are consistent with the previously reported $\pi^{0}$ cross-sections by BESIII, while the $K^{\pm}$ cross sections are systematically higher than the $K^0_S$ cross sections by a factor of approximately 1.4. These new results are in agreement with state-of-the-art QCD analyses at next-to-next-to-leading order accuracy, particularly in the large hadron momentum region at energy scales down to 3 GeV. These findings support the validity of isospin symmetry in parton fragmentation processes.