# Spectroscopy of Strange Mesons and First Observation of a Strange Crypto-Exotic State with $J^P=0^-$ with COMPASS

- Institution: CERN
- Department: EP Seminar
- Speaker: Stefan Wallner
- Year: 2025
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3023491)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

We measured the strange-meson spectrum in the scattering reaction $K^- + p\to K^-\pi^-\pi^+ + p$ with the COMPASS spectrometer at CERN. Using the world's largest sample of this reaction, we performed a comprehensive partial-wave analysis of the mesonic final state. It substantially extends the strange-meson spectrum covering twelve states with masses up to $2.4\, \text{GeV}/c^2$. We observe the first candidate for a crypto-exotic strange meson with $J^P=0^-$ and find $K_3$ and $K_4$ states consistent with predictions for the ground states.

Refreshments will be served at 10:30 .

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## Lectures

1. [Spectroscopy of Strange Mesons and First Observation of a Strange Crypto-Exotic State with $J^P=0^-$ with COMPASS](https://invisiblenetwork.ai/learn/cern/3023491/8603ac9ce15d), 55 min (CERN's player)