Angular distributions of leptons from J/ψ’s produced in 920 GeV fixed-target proton-nucleus collisions

被引：0

作者：

I. Abt

M. Adams

M. Agari

H. Albrecht

A. Aleksandrov

V. Amaral

A. Amorim

S. J. Aplin

V. Aushev

Y. Bagaturia

V. Balagura

M. Bargiotti

O. Barsukova

J. Bastos

J. Batista

C. Bauer

Th. S. Bauer

A. Belkov

Ar. Belkov

I. Belotelov

A. Bertin

B. Bobchenko

M. Böcker

A. Bogatyrev

G. Bohm

M. Bräuer

M. Bruinsma

M. Bruschi

P. Buchholz

T. Buran

J. Carvalho

P. Conde

C. Cruse

M. Dam

K. M. Danielsen

M. Danilov

S. De Castro

H. Deppe

X. Dong

H. B. Dreis

V. Egorytchev

K. Ehret

F. Eisele

D. Emeliyanov

S. Essenov

L. Fabbri

P. Faccioli

M. Feuerstack-Raible

J. Flammer

B. Fominykh

机构：

[1] NIKHEF,Department ECM, Faculty of Physics

[2] University of Barcelona,Institute of Engineering Physics

[3] Institute for High Energy Physics,Institut für Physik

[4] Tsinghua University,Department of Physics

[5] Humboldt-Universität zu Berlin,Institut für Physik

[6] Dipartimento di Fisica dell’ Università di Bologna and INFN Sezione di Bologna,Physikalisches Institut

[7] University of Cincinnati,Department of Physics

[8] LIP Coimbra,Institute for Nuclear Research

[9] Niels Bohr Institutet,Lehrstuhl für Informatik V

[10] Universität Dortmund,Max

[11] Joint Institute for Nuclear Research Dubna,Planck

[12] DESY,Institut für Physik

[13] Max-Planck-Institut für Kernphysik,Department of Physics

[14] Universität Heidelberg,Fachbereich Physik

[15] University of Houston,Fachbereich Physik

[16] Ukrainian Academy of Science,Institute for Nuclear Research

[17] J. Stefan Institute,Physik

[18] University of Ljubljana,Institut

[19] University of California,undefined

[20] Universität Mannheim,undefined

[21] University of Maribor,undefined

[22] Institute of Theoretical and Experimental Physics,undefined

[23] Werner-Heisenberg-Institut,undefined

[24] University of Oslo,undefined

[25] Universität Rostock,undefined

[26] Universität Siegen,undefined

[27] INRNE-BAS,undefined

[28] Universiteit Utrecht/NIKHEF,undefined

[29] DESY,undefined

[30] Universität Zürich,undefined

来源：

The European Physical Journal C | 2009年 / 60卷

关键词：

Systematic Uncertainty; Decay Channel; Beam Momentum; Polar Anisotropy; Azimuthal Anisotropy;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

A study of the angular distributions of leptons from decays of J/ψ’s produced in p-C and p-W collisions at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\sqrt{s}=41.6\mbox{~GeV}$\end{document} has been performed in the J/ψ Feynman-x region −0.34<xF<0.14 and for J/ψ transverse momenta up to 5.4 GeV/c. The data were collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The results, based on a clean selection of 2.3×105J/ψ’s reconstructed in both the e+e− and μ+μ− decay channels, indicate that J/ψ’s are produced polarized. The magnitude of the effect is maximal at low pT. For pT>1 GeV/c a significant dependence on the reference frame is found: the polar anisotropy is more pronounced in the Collins-Soper frame and almost vanishes in the helicity frame, where, instead, a significant azimuthal anisotropy arises.

引用

页码：517 / 524

页数：7

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