A novel interpretation of the "$\Theta^{+}(1540)$ pentaquark" peak

TL;DR

This paper presents a theoretical analysis indicating that the observed peak attributed to the $ heta^{+}(1540)$ pentaquark in a specific experiment may be an artifact caused by data analysis methods, suggesting the peak's significance is questionable.

Contribution

The study introduces a model demonstrating how experimental cuts and momentum assignments can artificially produce a peak resembling the $ heta^{+}(1540)$ signal.

Findings

The observed peak can be explained as an artifact of data analysis.

The peak's statistical significance is compatible with a 2σ fluctuation.

The method used in the experiment may create artificial signals.

Abstract

We use a theoretical model of the $\gamma ~d \to ~K^+ K^- ~n ~p $ reaction adapted to the experiment done at LEPS where a peak was observed and associated to the $\Theta^{+}(1540)$ pentaquark. The study shows that the method used in the experiment to associate momenta to the undetected proton and neutron, together with the chosen cuts, necessarily creates an artificial broad peak in the assumed $K^+ n$ invariant mass in the region of the claimed $\Theta^{+}(1540)$, such that the remaining strength seen for the experimental peak is compatible with a fluctuation of 2$\sigma$ significance.