Proposal of Direct Search for Strongly Bound States of ppbar, npbar Systems with High Intensity and Collective pbar beam

TL;DR

This paper proposes experimental methods using high-intensity antiproton beams to detect bound states of proton-antiproton and neutron-antiproton systems, aiming to clarify the nature of certain resonances like X(1860) and X(1835).

Contribution

It introduces new experimental approaches and analyzes existing data to search for direct evidence of ppbar and npbar bound states, including charged resonances, and discusses future measurement possibilities.

Findings

Data from Crystal Barrel supports the existence of X(1835).

Proposed techniques can probe the structure of X(1860) and X(1835).

Future experiments with high-intensity antiproton beams are promising.

Abstract

In this letter, we discuss the possibility to look for the direct evidence of the existence of the ppbar and npbar bound states. Measurement of the single \gamma ray from the ppbar and npbar systems at rest can directly confirm whether the X(1860) and X(1835) are the resonances which are strongly coupled to ppbar. In addition to the neutral candidate, a charged resonance $X^-$ is also proposed to be searched for in npbar channel. We find that the data from the Crystal Barrel experiment at LEAR/CERN can be used to confirm the X(1835) observed by BES Collaboration. The possibility of measuring the $\gamma$ spectrum below 100 MeV at the new experiment with cold high intensity $\pbar$ beam at GSI is discussed. These new techniques can be used to probe the structure of the X(1860) and X(1835) in the future.