Spin density matrix elements in exclusive ρ0 meson muoproduction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081731%3A_____%2F23%3A00579249" target="_blank" >RIV/68081731:_____/23:00579249 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68407700:21340/23:00371107 RIV/00216208:11320/23:10476524

Výsledek na webu

<a href="https://link.springer.com/article/10.1140/epjc/s10052-023-11359-4" target="_blank" >https://link.springer.com/article/10.1140/epjc/s10052-023-11359-4</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1140/epjc/s10052-023-11359-4" target="_blank" >10.1140/epjc/s10052-023-11359-4</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Spin density matrix elements in exclusive ρ0 meson muoproduction

Popis výsledku v původním jazyce

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ρ0 meson muoproduction at COMPASS using 160~GeV/c polarised μ+ and μ− beams impinging on a liquid hydrogen target. The measurement covers the kinematic range 5.0~GeV/c2 <W< 17.0~GeV/c2, 1.0 (GeV/c)2 <Q2< 10.0 (GeV/c)2 and 0.01 (GeV/c)2 <p2T< 0.5 (GeV/c)2. Here, W denotes the mass of the final hadronic system, Q2 the virtuality of the exchanged photon, and pT the transverse momentum of the ρ0 meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γ∗T→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a dominant contribution of natural-parity-exchange transitions and a very small contribution of unnatural-parity-exchange transitions, which is compatible with zero within experimental uncertainties. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow one to evaluate in a model-dependent way the role of parton helicity-flip GPDs in exclusive ρ0 production.

Název v anglickém jazyce

Spin density matrix elements in exclusive ρ0 meson muoproduction

Popis výsledku anglicky

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ρ0 meson muoproduction at COMPASS using 160~GeV/c polarised μ+ and μ− beams impinging on a liquid hydrogen target. The measurement covers the kinematic range 5.0~GeV/c2 <W< 17.0~GeV/c2, 1.0 (GeV/c)2 <Q2< 10.0 (GeV/c)2 and 0.01 (GeV/c)2 <p2T< 0.5 (GeV/c)2. Here, W denotes the mass of the final hadronic system, Q2 the virtuality of the exchanged photon, and pT the transverse momentum of the ρ0 meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γ∗T→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a dominant contribution of natural-parity-exchange transitions and a very small contribution of unnatural-parity-exchange transitions, which is compatible with zero within experimental uncertainties. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow one to evaluate in a model-dependent way the role of parton helicity-flip GPDs in exclusive ρ0 production.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Physical Journal C

ISSN

1434-6044

e-ISSN

1434-6052

Svazek periodika

83

Číslo periodika v rámci svazku

10

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

25

Strana od-do

924

Kód UT WoS článku

001095775200001

EID výsledku v databázi Scopus

2-s2.0-85174592149