An Experimental Review of the $\Theta^+$ Pentaquark

Abstract

Evidence for the $\Theta^+$ pentaquark is still sketchy at the present time. This state, if it exists, has a small width and consequently a small production cross section. No single experiment has overwhelming evidence for the $\Theta^+$ and some non-observations of the $\Theta^+$ are difficult to understand unless this exotic baryon also has an exotic production mechanism. However, new data from the LEPS and CLAS collaborations with higher statistics are on the way, which will likely resolve the question of whether the $\Theta^+$ exists.