25-29 September 2017
Salamanca, Spain
Europe/Zurich timezone

## Muoproduction of exotic charmonia at COMPASS

29 Sep 2017, 09:00
25m
Aula 2.7

#### Aula 2.7

Talk Exotic states and candidates

### Speaker

Dr Alexey Guskov (Joint Institute for Nuclear Research)

### Description

Exotic charmonium-like XYZ states have been targeted by various experiments in the last 15 years,
but their nature still is unknown. Photo-(muo)production, is a new promising instrument to study them.
COMPASS, a fixed target experiment at CERN, analyzed the full set of the data collected with a
muon beam between 2002 and 2011, covering the range from 7 GeV to 19 GeV in the centre-of-mass energy
of the photon-nucleon system.
Production of the X(3872) state in the reaction $\mu^+~N \rightarrow \mu^+(J/\psi\pi^+\pi^- )\pi^{\pm} N'$ has been observed with a statistical significance of around 5 $\sigma$. The product of the cross section and the branching fraction of the $X(3872)$ decay into $J/\psi\pi\pi$ is estimated as 71$\pm$28(stat)$\pm$39(syst) pb.
The results obtained for the production of the $Z_c^{\pm}(3900)$ will be also reported as well as future perspectives.

### Primary author

Dr Alexey Guskov (Joint Institute for Nuclear Research)