Publication: Comparison of transverse single-spin asymmetries for forward π0 production in polarized pp, pAl and pAu collisions at nucleon pair c.m. energy sNN =200 GeV
Дата
2021
Авторы
Adam, J.
Adamczyk, L.
Adams, J. R.
Adkins, J. K.
Alekseev, I.
Brandin, A. V.
Khyzhniak, Y. V.
Kochenda, L.
Kravtsov, P.
Nigmatkulov, G.
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Аннотация
© 2021 American Physical Society.The STAR collaboration reports a measurement of the transverse single-spin asymmetries, AN, for neutral pions produced in polarized proton collisions with protons (pp), with aluminum nuclei (pAl) and with gold nuclei (pAu) at a nucleon-nucleon center-of-mass energy of 200 GeV. Neutral pions are observed in the forward direction relative to the transversely polarized proton beam, in the pseudorapidity region 2.7<η<3.8. Results are presented for π0s observed in the STAR forward meson spectrometer electromagnetic calorimeter in narrow Feynman x (xF) and transverse momentum (pT) bins, spanning the range 0.17<xF<0.81 and 1.7<pT<6.0 GeV/c. For fixed xF<0.47, the asymmetries are found to rise with increasing transverse momentum. For larger xF, the asymmetry flattens or falls as pT increases. Parametrizing the ratio r(A)AN(pA)/AN(pp)=AP over the kinematic range, the ratio r(A) is found to depend only weakly on A, with P = -0.027±0.005. No significant difference in P is observed between the low-pT region, pT<2.5 GeV/c, where gluon saturation effects may play a role, and the high-pT region, pT>2.5 GeV/c. It is further observed that the value of AN is significantly larger for events with a large-pT isolated π0 than for events with a nonisolated π0 accompanied by additional jetlike fragments. The nuclear dependence r(A) is similar for isolated and nonisolated π0 events.
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Comparison of transverse single-spin asymmetries for forward π0 production in polarized pp, pAl and pAu collisions at nucleon pair c.m. energy sNN =200 GeV / Adam, J. [et al.] // Physical Review D. - 2021. - 103. - № 7. - 10.1103/PhysRevD.103.072005
URI
https://www.doi.org/10.1103/PhysRevD.103.072005
https://www.scopus.com/record/display.uri?eid=2-s2.0-85104681932&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000648577400001
https://openrepository.mephi.ru/handle/123456789/23930
https://www.scopus.com/record/display.uri?eid=2-s2.0-85104681932&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000648577400001
https://openrepository.mephi.ru/handle/123456789/23930