phi-meson production in proton-antiproton annihilation

TL;DR

This paper investigates phi-meson production in proton-antiproton annihilation, exploring how intrinsic strangeness in the nucleon affects the process and aligns with experimental data.

Contribution

It introduces three models for nucleon strangeness content and calculates their effects on phi-meson production, providing new insights into channel dependence and experimental consistency.

Findings

Strangeness models predict channel-dependent phi-meson production rates.

Nonrelativistic quark model results agree with recent experimental data.

Certain configurations lead to negative strangeness magnetic moments and spin contributions.

Abstract

Apparent channel-dependent violations of the OZI rule in nucleon-antinucleon annihilation reactions are discussed in the presence of an intrinsic strangeness component in the nucleon. Admixture of strange-antistrange quark pairs in the nucleon wave function enables the direct coupling to the phi-meson in the annihilation channel without violating the OZI rule. Three forms are considered in this work for the strangeness content of the proton wave function, namely, the uud cluster with a strange-antistrange sea quark component, kaon-hyperon clusters based on a simple chiral quark model, and the pentaquark picture. Nonrelativistic quark model calculations reveal that the strangeness magnetic moment and the strangeness contribution to the proton spin from the first two models are consistent with recent experimental data. For the third model, the uuds subsystem with the configurations FS[31]F[211]S[22] and FS[31]F[31]S[22] leads to negative values for the strangeness magnetic moment and the strangeness contribution to the proton spin. With effective quark line diagrams incorporating the 3P0 quark model we give estimates for the branching ratios of the proton-antiproton annihilation reactions at rest to two mesons. Results for the branching ratios of phi-meson production from atomic proton-antiproton s-wave states are for the first and third model found to be strongly channel dependent, in good agreement with measured rates.