Exploring the potential of antihyperons in nuclei with antiprotons

Abstract

A simple method to explore the interaction of antihyperons in nuclei by exclusive hyperon-antihyperon pair production close to threshold in antiproton nucleus interactions is proposed. Due to energy and momentum conservation event-by-event transverse momentum correlations of the produced hyperons and antihyperons contain information on the difference between their potentials. A schematic Monte Carlo simulation is used to illustrate the sensitivities of the proposed method for the reaction 1.66GeV/c antiproton+$^{12}$C $\to {\Lambda\bar{\Lambda}}$. For produced D-meson pairs at 6.7GeV/c the sensitivity of the transverse momenta correlation will probably be to small to deduce differences between the potentials for D$^+$ and D$^-$ mesons. However, for $\Xi\bar{\Xi}$ pairs produced at 2.9GeV/c the asymmetry is sufficiently sensitive to predicted differences between the $\Xi$ and $\bar{\Xi}$ potentials.Comment: updated references; several minor additions; format of figures modified for better representatio

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“…short distances [15]. Taking G-parity transformation [16] as a guidance a direct comparison of the interactions of baryons with that of antibaryons in nuclei may help to shed light on the nature of short-range baryon-baryon forces [17].…”

“…Antihyperons annihilate quickly in normal nuclei and spectroscopic information is therefore not directly accessible. In future quantitative information on the antihyperon potentials may be obtained via exclusive antihyperon-hyperon pair production close to threshold in antiproton-nucleus interactions [15]. Once these hyperons leave the nucleus and are detected, their asymptotic momentum distributions will reflect the depth of the respective potentials.…”

“…In Ref. [15] it was demonstrated that momentum correlations of coincident hyperon-antihyperon pairs can be used to extract information on the relative potential of hyperons and antihyperons in nuclei.…”

Exploring the nuclear potential of antihyperons with antiprotons at ${\overline{\rm\bf P}}{\rm\bf ANDA}$

“…Quantitative information on the antihyperon potentials relative to that of the corresponding hyperon may be obtained via exclusive antihyperon-hyperon pair production close to threshold in antiproton-nucleus interactions [21]. Once these hyperons leave the nucleus and are detected, their asymptotic momentum distributions will reflect the depth of the respective potentials.…”

“…However, since in the pp center-of-mass the distribution of the produced baryon-antibaryon pair will usually not be isotropic, the analysis can rely only on the transverse momenta of the outgoing baryons. In [21] it was demonstrated that the individual transverse momentum distributions alone do not allow to extract unambiguous information on the potential of antihyperons. Instead the transverse momentum asymmetry α T defined in terms of the transverse momenta of the coincident particles can be used to explore eventby-event correlations:…”