The Experimental Search for Pentaquark

TL;DR

This paper reviews experimental efforts to detect the pentaquark, focusing on evidence for the $ heta^+$ resonance, contrasting positive findings with null results, and discussing ongoing and future experiments at Jefferson Lab.

Contribution

It provides a comprehensive overview of experimental searches for the pentaquark, highlighting recent evidence and upcoming experiments in the field.

Findings

Evidence for the $ heta^+$ resonance with mass 1.52-1.55 GeV

Null results from some high-energy experiments

Ongoing and planned second-generation experiments at Jefferson Lab

Abstract

The existence of an anti-decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model. In the last year, several experimental groups have reported evidence for a S=+1 baryon resonance, with mass ranging from 1.52 and 1.55 GeV and width less than 25 MeV, by looking at the invariant mass of the $K N$ system. This resonance, has been identified with the lowest mass of the anti-decuplet, the $\Theta^+$. At the same time, there are a number of experiment, mostly at high energies, that report null results. An overview of the experimental results so far obtained will be given here together with a review of the second generation experiments currently ongoing and planned at Jefferson Lab Hall B.