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Charge asymmetry in $e^{+}e^{-}\to B^{(*)}\bar{B}^{(*)}$ processes in the vicinity of $Υ(4S)$

S. G. Salnikov, A. I. Milstein

TL;DR

The problem addressed is the energy dependence of e+e- annihilation into heavy-meson pairs near threshold, where simple Breit-Wigner descriptions fail. The approach employs a six-channel final-state interaction model, including Coulomb effects for charged channels and isotopic invariance violation through isoscalar and isovector potentials U_{ij}^{(0)} and U_{ij}^{(1)}, solved via a radial Schrödinger equation; cross sections are derived from short-distance production amplitudes and the channel-wavefunctions at the origin. The results reproduce the Belle-II measurement of the ratio R_{21} near the resonance and predict sizable, energy-dependent deviations in R_{21}, R_{43}, and R_{65} at higher energies, with a near-threshold B^{*}B^{*} state influencing other channels. The work demonstrates that multichannel interference and isotopic invariance violation can generate large energy-dependent effects in B^{(*)}ar{B}^{(*)} production, providing a concrete target for future experiments to map the interaction structure of B^{(*)} mesons.

Abstract

The effects of isotopic invariance violation in the processes $e^{+}e^{-}\to B\bar{B}$, $e^{+}e^{-}\to B^{*}\bar{B}$, and $e^{+}e^{-}\to B^{*}\bar{B}^{*}$ are considered in the energy range between the thresholds of $B^{+}B^{-}$ and $B_{s}^{0}\bar{B}_{s}^{0}$ production. The analysis is based on taking into account the final-state interaction in a six-channel problem. Our approach allowed us to obtain good agreement with recent Belle-II results for the ratio of the $B^{0}\bar{B}^{0}$ and $B^{+}B^{-}$ production cross sections in $e^{+}e^{-}$ annihilation in the vicinity of $Υ(4S)$. It is shown that at higher energies the ratios of the cross sections for pairs of neutral and charged $B^{(*)}$ mesons can differ significantly from unity. A detailed measurement of this effect will provide evidence that the nontrivial energy dependence of the $B^{(*)}\bar{B}^{(*)}$ production cross sections is a consequence of interference of the particle production amplitudes in the multichannel problem.

Charge asymmetry in $e^{+}e^{-}\to B^{(*)}\bar{B}^{(*)}$ processes in the vicinity of $Υ(4S)$

TL;DR

The problem addressed is the energy dependence of e+e- annihilation into heavy-meson pairs near threshold, where simple Breit-Wigner descriptions fail. The approach employs a six-channel final-state interaction model, including Coulomb effects for charged channels and isotopic invariance violation through isoscalar and isovector potentials U_{ij}^{(0)} and U_{ij}^{(1)}, solved via a radial Schrödinger equation; cross sections are derived from short-distance production amplitudes and the channel-wavefunctions at the origin. The results reproduce the Belle-II measurement of the ratio R_{21} near the resonance and predict sizable, energy-dependent deviations in R_{21}, R_{43}, and R_{65} at higher energies, with a near-threshold B^{*}B^{*} state influencing other channels. The work demonstrates that multichannel interference and isotopic invariance violation can generate large energy-dependent effects in B^{(*)}ar{B}^{(*)} production, providing a concrete target for future experiments to map the interaction structure of B^{(*)} mesons.

Abstract

The effects of isotopic invariance violation in the processes , , and are considered in the energy range between the thresholds of and production. The analysis is based on taking into account the final-state interaction in a six-channel problem. Our approach allowed us to obtain good agreement with recent Belle-II results for the ratio of the and production cross sections in annihilation in the vicinity of . It is shown that at higher energies the ratios of the cross sections for pairs of neutral and charged mesons can differ significantly from unity. A detailed measurement of this effect will provide evidence that the nontrivial energy dependence of the production cross sections is a consequence of interference of the particle production amplitudes in the multichannel problem.
Paper Structure (4 sections, 7 equations, 1 figure, 2 tables)

This paper contains 4 sections, 7 equations, 1 figure, 2 tables.

Table of Contents

  1. Introduction
  2. Description of model
  3. Comparison of predictions with experimental data
  4. Conclusion

Figures (1)

  • Figure 1: Predictions for the energy dependence of $R_{21}$, $R_{43}$ and $R_{65}$. Solid lines correspond to variant I, dashed lines correspond to variant II, and dotted lines correspond to variant III from Table \ref{['tab:params1']}. Experimental points for $R_{21}$ are recalculated from data in Ref. Abumusabh2025Measurements. The vertical dashed lines indicate the thresholds for the production of the corresponding states.