Measurement of the hard exclusive π0 muoproduction cross section at COMPASS

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081731%3A_____%2F25%3A00643484" target="_blank" >RIV/68081731:_____/25:00643484 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68407700:21340/25:00387267 RIV/46747885:24510/25:00014449 RIV/00216208:11320/25:10506535

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0370269325005933" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0370269325005933</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2025.139832" target="_blank" >10.1016/j.physletb.2025.139832</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Measurement of the hard exclusive π0 muoproduction cross section at COMPASS

Popis výsledku v původním jazyce

A new and detailed measurement of the cross section for hard exclusive neutral-pion muoproduction on the proton was performed in a wide kinematic region, with the photon virtuality Q 2 ranging from 1 to 8 (GeV/ c ) 2 and the Bjorken variable x B j ranging from 0.02 to 0.45. The data were collected at COMPASS at CERN using 160 GeV/ c longitudinally polarised μ + and μ − beams scattering off a 2.5 m long liquid hydrogen target. From the average of the measured μ + and μ − cross sections, the virtual-photon–proton cross section is determined as a function of the squared four-momentum transfer between the initial and final state proton in the range 0.08 (GeV/ c ) 2 < | t | < 0.64 (GeV/ c ) 2 . From its angular distribution, the combined contribution of transversely and longitudinally polarised photons are determined, as well as transverse–transverse and longitudinal–transverse interference contributions. They are studied as functions of four-momentum transfer | t | , photon virtuality Q 2 and virtual-photon energy ν . The longitudinal–transverse interference contribution is found to be compatible with zero. The significant transverse–transverse interference contribution reveals the existence of a dominant contribution by transversely polarised photons. This could provide clear experimental evidence for the chiral-odd GPD E ‾ T . In addition, the existence of a non-negligible contribution of longitudinally polarised photons is suggested by the | t | -dependence of the cross section at x B j < 0.1. Altogether, these results provide valuable input for future modelling of GPDs and thus of cross sections for exclusive pseudo-scalar meson production. Furthermore, they can be expected to facilitate the study of next-to-leading order corrections and higher-twist contributions.

Název v anglickém jazyce

Measurement of the hard exclusive π0 muoproduction cross section at COMPASS

Popis výsledku anglicky

A new and detailed measurement of the cross section for hard exclusive neutral-pion muoproduction on the proton was performed in a wide kinematic region, with the photon virtuality Q 2 ranging from 1 to 8 (GeV/ c ) 2 and the Bjorken variable x B j ranging from 0.02 to 0.45. The data were collected at COMPASS at CERN using 160 GeV/ c longitudinally polarised μ + and μ − beams scattering off a 2.5 m long liquid hydrogen target. From the average of the measured μ + and μ − cross sections, the virtual-photon–proton cross section is determined as a function of the squared four-momentum transfer between the initial and final state proton in the range 0.08 (GeV/ c ) 2 < | t | < 0.64 (GeV/ c ) 2 . From its angular distribution, the combined contribution of transversely and longitudinally polarised photons are determined, as well as transverse–transverse and longitudinal–transverse interference contributions. They are studied as functions of four-momentum transfer | t | , photon virtuality Q 2 and virtual-photon energy ν . The longitudinal–transverse interference contribution is found to be compatible with zero. The significant transverse–transverse interference contribution reveals the existence of a dominant contribution by transversely polarised photons. This could provide clear experimental evidence for the chiral-odd GPD E ‾ T . In addition, the existence of a non-negligible contribution of longitudinally polarised photons is suggested by the | t | -dependence of the cross section at x B j < 0.1. Altogether, these results provide valuable input for future modelling of GPDs and thus of cross sections for exclusive pseudo-scalar meson production. Furthermore, they can be expected to facilitate the study of next-to-leading order corrections and higher-twist contributions.

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

2025

Kód důvěrnosti údajů

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

Název periodika

Physics Letters. B

ISSN

0370-2693

e-ISSN

1873-2445

Svazek periodika

870

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

15

Strana od-do

139832

Kód UT WoS článku

001642054700001

EID výsledku v databázi Scopus

2-s2.0-105021024118