TY - JOUR
T1 - Interpretation of angular distributions of Z-boson production at colliders
AU - Peng, Jen Chieh
AU - Chang, Wen Chen
AU - McClellan, Randall Evan
AU - Teryaev, Oleg
N1 - Funding Information:
We gratefully acknowledge helpful discussion with Aram Kotzinian, Hsiang-Nan Li, and Stephane Platchkov. This work was supported in part by the U.S. National Science Foundation ( NSF PHY 15-06416 ) and the National Science Council of the Republic of China.
Publisher Copyright:
© 2016 The Authors.
PY - 2016/7/10
Y1 - 2016/7/10
N2 - High precision data of dilepton angular distributions in γ*/Z production were reported recently by the CMS Collaboration covering a broad range of the dilepton transverse momentum, qT, up to ~300 GeV. Pronounced qT dependencies of the λ and ν parameters, characterizing the cos2 θ and cos 2φ angular distributions, were found. Violation of the Lam-Tung relation was also clearly observed. We show that the qT dependence of λ allows a determination of the relative contributions of the qq annihilation versus the qG Compton process. The violation of the Lam-Tung relation is attributed to the presence of a non-zero component of the q-q axis in the direction normal to the "hadron plane" formed by the colliding hadrons. The magnitude of the violation of the Lam-Tung relation is shown to reflect the amount of this 'non-coplanarity". The observed qT dependencies of λ and ν from the CMS and the earlier CDF data can be well described using this approach.
AB - High precision data of dilepton angular distributions in γ*/Z production were reported recently by the CMS Collaboration covering a broad range of the dilepton transverse momentum, qT, up to ~300 GeV. Pronounced qT dependencies of the λ and ν parameters, characterizing the cos2 θ and cos 2φ angular distributions, were found. Violation of the Lam-Tung relation was also clearly observed. We show that the qT dependence of λ allows a determination of the relative contributions of the qq annihilation versus the qG Compton process. The violation of the Lam-Tung relation is attributed to the presence of a non-zero component of the q-q axis in the direction normal to the "hadron plane" formed by the colliding hadrons. The magnitude of the violation of the Lam-Tung relation is shown to reflect the amount of this 'non-coplanarity". The observed qT dependencies of λ and ν from the CMS and the earlier CDF data can be well described using this approach.
KW - Drell-Yan process
KW - Lam-Tung relation
KW - QCD
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U2 - 10.1016/j.physletb.2016.05.035
DO - 10.1016/j.physletb.2016.05.035
M3 - Article
AN - SCOPUS:84969175326
VL - 758
SP - 384
EP - 388
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
ER -