Spin density matrix elements in exclusive ω meson muoproduction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081731%3A_____%2F21%3A00549445" target="_blank" >RIV/68081731:_____/21:00549445 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/46747885:24510/23:00012058

Výsledek na webu

<a href="https://link.springer.com/article/10.1140%2Fepjc%2Fs10052-020-08740-y" target="_blank" >https://link.springer.com/article/10.1140%2Fepjc%2Fs10052-020-08740-y</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1140/epjc/s10052-020-08740-y" target="_blank" >10.1140/epjc/s10052-020-08740-y</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Spin density matrix elements in exclusive ω meson muoproduction

Popis výsledku v původním jazyce

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive omega meson muoproduction on the proton at COMPASS using 160 GeV/c polarised mu(+) and mu(-) beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c(2) < W < 17.0 GeV/c(2), with the average kinematics < Q(2)>= 2.1 (GeV/c)(2), < W >=7.6 GeV/c(2), and < p(T)(2)>=0.16 (GeV/c)(2). Here, Q(2) denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and p(T) the transverse momentum of the omega 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 (gamma(*)(T)> V-L) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive omega production.

Název v anglickém jazyce

Spin density matrix elements in exclusive ω meson muoproduction

Popis výsledku anglicky

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive omega meson muoproduction on the proton at COMPASS using 160 GeV/c polarised mu(+) and mu(-) beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c(2) < W < 17.0 GeV/c(2), with the average kinematics < Q(2)>= 2.1 (GeV/c)(2), < W >=7.6 GeV/c(2), and < p(T)(2)>=0.16 (GeV/c)(2). Here, Q(2) denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and p(T) the transverse momentum of the omega 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 (gamma(*)(T)> V-L) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive omega production.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

<a href="/cs/project/LM2018104" target="_blank" >LM2018104: Výzkumná infrastruktura pro experimenty v CERN</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

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

81

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

22

Strana od-do

126

Kód UT WoS článku

000617390500004

EID výsledku v databázi Scopus

2-s2.0-85107340629