Strange-Meson Spectroscopy -- from COMPASS to AMBER

TL;DR

This paper discusses strange meson spectroscopy, analyzing COMPASS data to identify known and potential exotic states, and proposes a new high-precision measurement at the AMBER experiment to overcome current limitations.

Contribution

It presents a detailed partial-wave analysis of COMPASS data and proposes a new experiment at CERN to improve strange meson spectroscopy.

Findings

Identification of signals corresponding to known states like K*_2(1430)

Indications of a potential exotic strange meson near 1630 MeV

Proposal for a new high-precision measurement at AMBER

Abstract

COMPASS is a multi-purpose fixed-target experiment at CERN's M2 beam line aimed at studying the structure and spectrum of hadrons. It has collected the so far world's largest data set on diffractive production of the $K^-\pi^-\pi^+$ final state, which in principle gives access to all strange mesons. Based on this data set, we performed an elaborate partial-wave analysis. It reveals signals in the mass region of well-known states, such as the $K_2^*(1430)$. In addition, we found indications for a resonance-like signal in the mass region of the $K(1630)$. This state would be a supernumerary state and hence could be a candidate for an exotic strange meson. The partial-wave analysis is limited in some areas by the limited kinematic coverage of the final-state particle identification of the COMPASS setup. To overcome this limitation, we propose a new high-precision strange-meson spectroscopy measurement at the AMBER experiment, which will be located at CERN's M2 beam line.