Электронный каталог

Статья

Acharya, S.
First Polarisation Measurement of Coherently Photoproduced J∕*q in Ultra-Peripheral Pb–Pb Collisions at *%s&sub(NN) = 5.02 TeV / S.Acharya, B.Batyunya, C.Ceballos Sanchez, R.A.Diaz, S.Grigoryan, A.Kondratyev, L.Malinina, K.Mikhaylov, P.Nomokonov, V.Pozdniakov, E.Rogochaya, G.Romanenko, B.Rumyantsev, A.Vodopyanov, [ALICE Collab.]. – Text : electronic // Physics Letters B. – 2025. – Vol. 865. – P. 139466. – URL: https://doi.org/10.1016/j.physletb.2025.139466. – Bibliogr.: 49.

The first measurement of the polarisation of coherently photoproduced J∕*q mesons in ultra-peripheral Pb–Pb collisions, using data at *%𝑠&sub(NN) = 5.02 TeV, is presented. The J∕*q meson is measured via its dimuon decay channel in the forward rapidity interval −4.0 < 𝑦 < −2.5 using the ALICE detector at the CERN LHC. An event sample corresponding to an integrated luminosity of 750 *mb&sup(−1) ± 5% (syst) is analysed. Hadronic activity is highly suppressed since the interaction is mediated by a photon. The polar and azimuthal angle distributions of the decay muons are measured, and the polarisation parameters *l&sub(*y), *l&sub(*f), *l&sub(*q*f) are extracted. The analysis is carried out in the helicity frame. The results are found to be consistent with a transversely polarised J∕*q. These values are compared with previous measurements by the H1 and ZEUS experiments. The polarisation parameters of coherent J∕*q photoproduction in Pb–Pb collisions are found to be consistent with the 𝑠-channel helicity conservation hypothesis.



Спец.(статьи,препринты) = С 346.6а1 - Векторные мезоны
Спец.(статьи,препринты) = С 343 е2 - Взаимодействие релятивистских ядер с ядрами
ОИЯИ = ОИЯИ (JINR)2025