Searching for signatures around 1920 MeV of a $N^*$ state of three hadron nature

TL;DR

This paper investigates a peak around 1920 MeV in a photon-proton reaction, proposing it as a three-hadron bound state with specific quantum numbers, supported by theoretical arguments and suggesting experimental tests for validation.

Contribution

It predicts a new $N^*$ state as a $K ar{K}N$ bound state with specific components, and proposes experimental methods to verify this hypothesis.

Findings

Supports the interpretation of the 1920 MeV peak as a $K ar{K}N$ bound state.

Suggests polarization experiments as a test for the predicted state.

Recommends studying cross sections near threshold to confirm the state.

Abstract

We provide a series of arguments which support the idea that the peak seen in the $\gamma p \to K^+ \Lambda$ reaction around 1920 MeV should correspond to the recently predicted state of $J^P=1/2^+$ as a bound state of $K \bar{K}N$ with a mixture of $a_0(980)N$ and $f_0(980)N$ components. At the same time we propose polarization experiments in that reaction as a further test of the prediction, as well as a study of the total cross section for $\gamma p \to K^+ K^- p$ at energies close to threshold and of $d \sigma/d M_{inv}$ for invariant masses close to the two kaon threshold.