Angular distributions of leptons from J/ ψ's produced in 920 GeV fixed-target proton-nucleus collisions
| dc.contributor.author | Conde, P. | |
| dc.contributor.author | Garrido Beltrán, Lluís | |
| dc.contributor.author | Peralta, D. | |
| dc.contributor.author | HERA-B Collaboration | |
| dc.date.accessioned | 2014-07-28T10:44:00Z | |
| dc.date.available | 2014-07-28T10:44:00Z | |
| dc.date.issued | 2009 | |
| dc.date.updated | 2014-07-28T10:44:00Z | |
| dc.description.abstract | A study of the angular distributions of leptons from decays of J/ψ"s produced in p-C and p-W collisions at s√=41.6~GeV has been performed in the J/ψ Feynman-x region −0.34<x F <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 2.3×105 J/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 p T . For p T >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. | |
| dc.format.extent | 8 p. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.idgrec | 577648 | |
| dc.identifier.issn | 1434-6044 | |
| dc.identifier.uri | https://hdl.handle.net/2445/56366 | |
| dc.language.iso | eng | |
| dc.publisher | Società Italiana di Fisica & Springer Verlag | |
| dc.relation.isformatof | Reproduccció del document publicat a: http://doi.dx.org/ 10.1140/epjc/s10052-009-0957-7 | |
| dc.relation.ispartof | European Physical Journal C, 2009, vol. 60, num. 4, p. 517-524 | |
| dc.relation.uri | http://dx.doi.org/10.1140/epjc/s10052-009-0957-7 | |
| dc.rights | cc by (c) HERA-B Collaboration, 2009 | |
| dc.rights.accessRights | info:eu-repo/semantics/openAccess | |
| dc.rights.uri | http://creativecommons.org/licenses/by/3.0/ | |
| dc.source | Articles publicats en revistes (Física Quàntica i Astrofísica) | |
| dc.subject.classification | Astronomia | |
| dc.subject.classification | Astrofísica | |
| dc.subject.classification | Física nuclear | |
| dc.subject.classification | Partícules (Física nuclear) | |
| dc.subject.classification | Teoria quàntica de camps | |
| dc.subject.other | Astronomy | |
| dc.subject.other | Astrophysics | |
| dc.subject.other | Nuclear physics | |
| dc.subject.other | Particles (Nuclear physics) | |
| dc.subject.other | Quantum field theory | |
| dc.title | Angular distributions of leptons from J/ ψ's produced in 920 GeV fixed-target proton-nucleus collisions | |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion |
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