PoS - Proceedings of Science
Volume 346 - 23rd International Spin Physics Symposium (SPIN2018) - Parallel Session: 3D Structure of the Nucleon: GPDs and Form Factors (C. Lorce and S. Niccolai)
Spin-density matrix elements in hard exclusive muoproduction of $\omega$ mesons at COMPASS
B. Marianski*  on behalf of the COMPASS Collaboration
Full text: pdf
Pre-published on: August 19, 2019
Published on: August 23, 2019
Abstract
Spin density matrix elements (SDMEs) have been determined for
exclusive
$\omega$ meson production on unpolarized protons, in the COMPASS
kinematic region 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)$^2$ which corresponds to
$\left< Q^{2} \right>= 2.1$~(GeV/c)$^2$), $\left< W \right>= 7.6$~GeV/$c^2$
and
$\left<p^{2}_{T} \right> = 0.16$~(GeV/c)$^2$) mean values.
Using extracted SDMEs values the contribution of unnatural parity exchange
amplitudes and
the hypothesis of s-channel helicity conservation (SCHC) were
studied. Certain matrix elements e.g. $ r^{5}_{00}$ corresponding to
transition $\gamma^*_T \to
V_L$ indicate violation of SCHC in exclusive $\omega $ production.
A sizable contribution of unnatural parity exchange amplitudes is
found for the exclusive $\omega$ meson muoproduction, and there is a
clear
indication of its decrease with increasing W.
DOI: https://doi.org/10.22323/1.346.0073
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.