# Spin Density Matrix Elements for Exclusive $\rho^{0}$ Meson Muoproduction at COMPASS

### Submission summary

 As Contributors: Witold Augustyniak Preprint link: scipost_202107_00046v1 Date submitted: 2021-07-22 12:44 Submitted by: Augustyniak, Witold Submitted to: SciPost Physics Proceedings Proceedings issue: DIS2021 Academic field: Physics Specialties: High-Energy Physics - Experiment Approach: Experimental

### Abstract

Spin density matrix elements were extracted from COMPASS data for exclusive $\rho^{0}$ meson muoproduction on a liquid hydrogen target. The measurement cover the kinematic range of 1.0 (GeV/$c$)$^2$ $< Q^{2} <$ 10.0 (GeV/$c$)$^2$, 5.0 GeV/$c^2$ $< W <$ 17.0 GeV/$c^2$ and 0.01 (GeV/$c$)$^2$ $<p^{2}_{T} <$ 0.5 (GeV/$c$)$^2$. Here, $W$ denotes the mass of the final hadronic system, $Q^{2}$ the virtuality of the exchanged photon and $p_{T}$ the transverse momentum of the $\rho^{0}$ meson with respect to the virtual-photon direction. We observe a violation of s-channel helicity conservation for the transition $\gamma^{*}_{T} \to \rho^{0}_{L}$. Additionally, we find a dominant contribution of the natural-parity-exchange transitions. }

###### Current status:
Editor-in-charge assigned

### Submission & Refereeing History

Submission scipost_202107_00046v1 on 22 July 2021