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

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; M. Funcke; Ll Garrido; A. Gellrich; B. Giacobbe; J. Gläß; D. Goloubkov; Y. Golubkov; A. Golutvin; I. Golutvin; I. Gorbounov; A. Gorišek; O. Gouchtchine; D. C. Goulart; S. Gradl; W. Gradl; F. Grimaldi; J. Groth-Jensen; Yu Guilitsky; J. D. Hansen; J. M. Hernández; W. Hofmann; M. Hohlmann; T. Hott; W. Hulsbergen; U. Husemann; O. Igonkina; M. Ispiryan; T. Jagla; C. Jiang; H. Kapitza; S. Karabekyan; N. Karpenko; S. Keller; J. Kessler; F. Khasanov; Yu Kiryushin; I. Kisel; E. Klinkby; K. T. Knöpfle; H. Kolanoski; S. Korpar; C. Krauss; P. Kreuzer; P. Križan; D. Krücker; S. Kupper; T. Kvaratskheliia; A. Lanyov; K. Lau; B. Lewendel; T. Lohse; B. Lomonosov; R. Männer; R. Mankel; S. Masciocchi; I. Massa; I. Matchikhilian; G. Medin; M. Medinnis; M. Mevius; A. Michetti; Yu Mikhailov; R. Mizuk; R. Muresan; M. Zur Nedden; M. Negodaev; M. Nörenberg; S. Nowak; M. T.Núñez Pardo De Vera; M. Ouchrif; F. Ould-Saada; C. Padilla; D. Peralta; R. Pernack; R. Pestotnik; B. A.A. Petersen; M. Piccinini; M. A. Pleier; M. Poli; V. Popov; D. Pose; S. Prystupa; V. Pugatch; Y. Pylypchenko; J. Pyrlik; K. Reeves; D. Reßing; H. Rick; I. Riu; P. Robmann; I. Rostovtseva; V. Rybnikov; F. Sánchez; A. Sbrizzi; M. Schmelling; B. Schmidt; A. Schreiner; H. Schröder; U. Schwanke; A. J. Schwartz; A. S. Schwarz; B. Schwenninger; B. Schwingenheuer; F. Sciacca; N. Semprini-Cesari; S. Shuvalov; L. Silva; L. Sözüer; S. Solunin; A. Somov; S. Somov; J. Spengler; R. Spighi; A. Spiridonov; A. Stanovnik; M. Starič; C. Stegmann; H. S. Subramania; M. Symalla; I. Tikhomirov; M. Titov; I. Tsakov; U. Uwer; C. Van Eldik; Yu Vassiliev; M. Villa; A. Vitale; I. Vukotic; H. Wahlberg; A. H. Walenta; M. Walter; J. J. Wang; D. Wegener; U. Werthenbach; H. Wolters; R. Wurth; A. Wurz; S. Xella-Hansen; Yu Zaitsev; M. Zavertyaev; T. Zeuner; A. Zhelezov; Z. Zheng; R. Zimmermann; T. Živko; A. Zoccoli

doi:10.1140/epjc/s10052-009-0957-7

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

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, M. Funcke, Ll Garrido, A. Gellrich, B. Giacobbe, J. Gläß, D. Goloubkov, Y. Golubkov, A. Golutvin, I. Golutvin, I. Gorbounov, A. Gorišek, O. Gouchtchine, D. C. Goulart, S. Gradl, W. Gradl, F. Grimaldi, J. Groth-Jensen, Yu Guilitsky, J. D. Hansen, J. M. Hernández, W. Hofmann, M. Hohlmann, T. Hott, W. Hulsbergen, U. Husemann, O. Igonkina, M. Ispiryan, T. Jagla, C. Jiang, H. Kapitza, S. Karabekyan, N. Karpenko, S. Keller, J. Kessler, F. Khasanov, Yu Kiryushin, I. Kisel, E. Klinkby, K. T. Knöpfle, H. Kolanoski, S. Korpar, C. Krauss, P. Kreuzer, P. Križan, D. Krücker, S. Kupper, T. Kvaratskheliia, A. Lanyov, K. Lau, B. Lewendel, T. Lohse, B. Lomonosov, R. Männer, R. Mankel, S. Masciocchi, I. Massa, I. Matchikhilian, G. Medin, M. Medinnis, M. Mevius, A. Michetti, Yu Mikhailov, R. Mizuk, R. Muresan, M. Zur Nedden, M. Negodaev, M. Nörenberg, S. Nowak, M. T.Núñez Pardo De Vera, M. Ouchrif, F. Ould-Saada, C. Padilla, D. Peralta, R. Pernack, R. Pestotnik, B. A.A. Petersen, M. Piccinini, M. A. Pleier, M. Poli, V. Popov, D. Pose, S. Prystupa, V. Pugatch, Y. Pylypchenko, J. Pyrlik, K. Reeves, D. Reßing, H. Rick, I. Riu, P. Robmann, I. Rostovtseva, V. Rybnikov, F. Sánchez, A. Sbrizzi, M. Schmelling, B. Schmidt, A. Schreiner, H. Schröder, U. Schwanke, A. J. Schwartz, A. S. Schwarz, B. Schwenninger, B. Schwingenheuer, F. Sciacca, N. Semprini-Cesari, S. Shuvalov, L. Silva, L. Sözüer, S. Solunin, A. Somov, S. Somov, J. Spengler, R. Spighi, A. Spiridonov, A. Stanovnik, M. Starič, C. Stegmann, H. S. Subramania, M. Symalla, I. Tikhomirov, M. Titov, I. Tsakov, U. Uwer, C. Van Eldik, Yu Vassiliev, M. Villa, A. Vitale, I. Vukotic, H. Wahlberg, A. H. Walenta, M. Walter, J. J. Wang, D. Wegener, U. Werthenbach, H. Wolters, R. Wurth, A. Wurz, S. Xella-Hansen, Yu Zaitsev, M. Zavertyaev, T. Zeuner, A. Zhelezov, Z. Zheng, R. Zimmermann, T. Živko, A. Zoccoli

Max-Planck-Institut für Physik
Institut für Physik
University of Dortmund
Max-Planck-Institut für Kernphysik
c/o DESY
LIP Coimbra
Institute for Nuclear Research
Institute of Nuclear Research, National Academy of Sciences in Ukraine
High Energy Physics Institute
Institute for Theoretical and Experimental Physics
Dipartimento di Fisica
University of Bologna
Joint Institute for Nuclear Research, Dubna
Science Park 105
Fachbereich Physik
Universität Siegen
Universiteit Utrecht
Department of Physics
University of Oslo
Department ECM
University of Barcelona
Niels Bohr Institutet
Physikalisches Institut
University of Heidelberg
Institute of High Energy Physics, Chinese Academy of Sciences
Informatik V
University of Mannheim
National Research Nuclear University MEPhI
Moscow State University
Department of Biochemistry and Molecular and Structural Biology
Department of Physics
University of Cincinnati
Kurchatov Institute
University of Houston
Fachbereich Physik
Universität Rostock
Institut für Physik
Humboldt-Universität zu Berlin
University of Maribor
University of California, Los Angeles
University of Ljubljana
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
Dipartimento di Ene
University of Florence
Physik-Institut
University of Zurich
Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences
Fondazione Giuseppe Occhialini
Institute of Engineering Physics
Tsinghua University

Research output: Contribution to journal › Article › peer-review

33 Citations (Scopus)

Abstract

A study of the angular distributions of leptons from decays of J/ψ's produced in p-C and p-W collisions at sqrt{s}=41.6\mbox{∼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.

Original language	English
Pages (from-to)	517-524
Number of pages	8
Journal	European Physical Journal C
Volume	60
Issue number	4
DOIs	https://doi.org/10.1140/epjc/s10052-009-0957-7
Publication status	Published - 1 Apr 2009
Externally published	Yes

Access to Document

10.1140/epjc/s10052-009-0957-7

Cite this

Abt, I., Adams, M., Agari, M., Albrecht, H., Aleksandrov, A., Amaral, V., Amorim, A., Aplin, S. J., Aushev, V., Bagaturia, Y., Balagura, V., Bargiotti, M., Barsukova, O., Bastos, J., Batista, J., Bauer, C., Bauer, T. S., Belkov, A., Belkov, A., ... Zoccoli, A. (2009). Angular distributions of leptons from J/ψ's produced in 920 GeV fixed-target proton-nucleus collisions. European Physical Journal C, 60(4), 517-524. https://doi.org/10.1140/epjc/s10052-009-0957-7

@article{c1b889cfbe8643268f52f53f6097b844,

title = "Angular distributions of leptons from J/ψ's produced in 920 GeV fixed-target proton-nucleus collisions",

abstract = "A study of the angular distributions of leptons from decays of J/ψ's produced in p-C and p-W collisions at sqrt\{s\}=41.6\textbackslash{}mbox\{∼GeV\} has been performed in the J/ψ Feynman-x region -0.34F <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{\texttimes}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.",

author = "I. Abt and M. Adams and M. Agari and H. Albrecht and A. Aleksandrov and V. Amaral and A. Amorim and Aplin, \{S. J.\} and V. Aushev and Y. Bagaturia and V. Balagura and M. Bargiotti and O. Barsukova and J. Bastos and J. Batista and C. Bauer and Bauer, \{Th S.\} and A. Belkov and Ar Belkov and I. Belotelov and A. Bertin and B. Bobchenko and M. B{\"o}cker and A. Bogatyrev and G. Bohm and M. Br{\"a}uer and M. Bruinsma and M. Bruschi and P. Buchholz and T. Buran and J. Carvalho and P. Conde and C. Cruse and M. Dam and Danielsen, \{K. M.\} and M. Danilov and \{De Castro\}, S. and H. Deppe and X. Dong and Dreis, \{H. B.\} and V. Egorytchev and K. Ehret and F. Eisele and D. Emeliyanov and S. Essenov and L. Fabbri and P. Faccioli and M. Feuerstack-Raible and J. Flammer and B. Fominykh and M. Funcke and Ll Garrido and A. Gellrich and B. Giacobbe and J. Gl{\"a}{\ss} and D. Goloubkov and Y. Golubkov and A. Golutvin and I. Golutvin and I. Gorbounov and A. Gori{\v s}ek and O. Gouchtchine and Goulart, \{D. C.\} and S. Gradl and W. Gradl and F. Grimaldi and J. Groth-Jensen and Yu Guilitsky and Hansen, \{J. D.\} and Hern{\'a}ndez, \{J. M.\} and W. Hofmann and M. Hohlmann and T. Hott and W. Hulsbergen and U. Husemann and O. Igonkina and M. Ispiryan and T. Jagla and C. Jiang and H. Kapitza and S. Karabekyan and N. Karpenko and S. Keller and J. Kessler and F. Khasanov and Yu Kiryushin and I. Kisel and E. Klinkby and Kn{\"o}pfle, \{K. T.\} and H. Kolanoski and S. Korpar and C. Krauss and P. Kreuzer and P. Kri{\v z}an and D. Kr{\"u}cker and S. Kupper and T. Kvaratskheliia and A. Lanyov and K. Lau and B. Lewendel and T. Lohse and B. Lomonosov and R. M{\"a}nner and R. Mankel and S. Masciocchi and I. Massa and I. Matchikhilian and G. Medin and M. Medinnis and M. Mevius and A. Michetti and Yu Mikhailov and R. Mizuk and R. Muresan and \{Zur Nedden\}, M. and M. Negodaev and M. N{\"o}renberg and S. Nowak and \{De Vera\}, \{M. T.N{\'u}{\~n}ez Pardo\} and M. Ouchrif and F. Ould-Saada and C. Padilla and D. Peralta and R. Pernack and R. Pestotnik and Petersen, \{B. A.A.\} and M. Piccinini and Pleier, \{M. A.\} and M. Poli and V. Popov and D. Pose and S. Prystupa and V. Pugatch and Y. Pylypchenko and J. Pyrlik and K. Reeves and D. Re{\ss}ing and H. Rick and I. Riu and P. Robmann and I. Rostovtseva and V. Rybnikov and F. S{\'a}nchez and A. Sbrizzi and M. Schmelling and B. Schmidt and A. Schreiner and H. Schr{\"o}der and U. Schwanke and Schwartz, \{A. J.\} and Schwarz, \{A. S.\} and B. Schwenninger and B. Schwingenheuer and F. Sciacca and N. Semprini-Cesari and S. Shuvalov and L. Silva and L. S{\"o}z{\"u}er and S. Solunin and A. Somov and S. Somov and J. Spengler and R. Spighi and A. Spiridonov and A. Stanovnik and M. Stari{\v c} and C. Stegmann and Subramania, \{H. S.\} and M. Symalla and I. Tikhomirov and M. Titov and I. Tsakov and U. Uwer and \{Van Eldik\}, C. and Yu Vassiliev and M. Villa and A. Vitale and I. Vukotic and H. Wahlberg and Walenta, \{A. H.\} and M. Walter and Wang, \{J. J.\} and D. Wegener and U. Werthenbach and H. Wolters and R. Wurth and A. Wurz and S. Xella-Hansen and Yu Zaitsev and M. Zavertyaev and T. Zeuner and A. Zhelezov and Z. Zheng and R. Zimmermann and T. {\v Z}ivko and A. Zoccoli",

year = "2009",

month = apr,

day = "1",

doi = "10.1140/epjc/s10052-009-0957-7",

language = "English",

volume = "60",

pages = "517--524",

journal = "European Physical Journal C",

issn = "1434-6044",

publisher = "Springer Nature",

number = "4",

}

Abt, I, Adams, M, Agari, M, Albrecht, H, Aleksandrov, A, Amaral, V, Amorim, A, Aplin, SJ, Aushev, V, Bagaturia, Y, Balagura, V, Bargiotti, M, Barsukova, O, Bastos, J, Batista, J, Bauer, C, Bauer, TS, Belkov, A, Belkov, A, Belotelov, I, Bertin, A, Bobchenko, B, Böcker, M, Bogatyrev, A, Bohm, G, Bräuer, M, Bruinsma, M, Bruschi, M, Buchholz, P, Buran, T, Carvalho, J, Conde, P, Cruse, C, Dam, M, Danielsen, KM, Danilov, M, De Castro, S, Deppe, H, Dong, X, Dreis, HB, Egorytchev, V, Ehret, K, Eisele, F, Emeliyanov, D, Essenov, S, Fabbri, L, Faccioli, P, Feuerstack-Raible, M, Flammer, J, Fominykh, B, Funcke, M, Garrido, L, Gellrich, A, Giacobbe, B, Gläß, J, Goloubkov, D, Golubkov, Y, Golutvin, A, Golutvin, I, Gorbounov, I, Gorišek, A, Gouchtchine, O, Goulart, DC, Gradl, S, Gradl, W, Grimaldi, F, Groth-Jensen, J, Guilitsky, Y, Hansen, JD, Hernández, JM, Hofmann, W, Hohlmann, M, Hott, T, Hulsbergen, W, Husemann, U, Igonkina, O, Ispiryan, M, Jagla, T, Jiang, C, Kapitza, H, Karabekyan, S, Karpenko, N, Keller, S, Kessler, J, Khasanov, F, Kiryushin, Y, Kisel, I, Klinkby, E, Knöpfle, KT, Kolanoski, H, Korpar, S, Krauss, C, Kreuzer, P, Križan, P, Krücker, D, Kupper, S, Kvaratskheliia, T, Lanyov, A, Lau, K, Lewendel, B, Lohse, T, Lomonosov, B, Männer, R, Mankel, R, Masciocchi, S, Massa, I, Matchikhilian, I, Medin, G, Medinnis, M, Mevius, M, Michetti, A, Mikhailov, Y, Mizuk, R, Muresan, R, Zur Nedden, M, Negodaev, M, Nörenberg, M, Nowak, S, De Vera, MTNP, Ouchrif, M, Ould-Saada, F, Padilla, C, Peralta, D, Pernack, R, Pestotnik, R, Petersen, BAA, Piccinini, M, Pleier, MA, Poli, M, Popov, V, Pose, D, Prystupa, S, Pugatch, V, Pylypchenko, Y, Pyrlik, J, Reeves, K, Reßing, D, Rick, H, Riu, I, Robmann, P, Rostovtseva, I, Rybnikov, V, Sánchez, F, Sbrizzi, A, Schmelling, M, Schmidt, B, Schreiner, A, Schröder, H, Schwanke, U, Schwartz, AJ, Schwarz, AS, Schwenninger, B, Schwingenheuer, B, Sciacca, F, Semprini-Cesari, N, Shuvalov, S, Silva, L, Sözüer, L, Solunin, S, Somov, A, Somov, S, Spengler, J, Spighi, R, Spiridonov, A, Stanovnik, A, Starič, M, Stegmann, C, Subramania, HS, Symalla, M, Tikhomirov, I, Titov, M, Tsakov, I, Uwer, U, Van Eldik, C, Vassiliev, Y, Villa, M, Vitale, A, Vukotic, I, Wahlberg, H, Walenta, AH, Walter, M, Wang, JJ, Wegener, D, Werthenbach, U, Wolters, H, Wurth, R, Wurz, A, Xella-Hansen, S, Zaitsev, Y, Zavertyaev, M, Zeuner, T, Zhelezov, A, Zheng, Z, Zimmermann, R, Živko, T & Zoccoli, A 2009, 'Angular distributions of leptons from J/ψ's produced in 920 GeV fixed-target proton-nucleus collisions', European Physical Journal C, vol. 60, no. 4, pp. 517-524. https://doi.org/10.1140/epjc/s10052-009-0957-7

TY - JOUR

T1 - Angular distributions of leptons from J/ψ's produced in 920 GeV fixed-target proton-nucleus collisions

AU - Abt, I.

AU - Adams, M.

AU - Agari, M.

AU - Albrecht, H.

AU - Aleksandrov, A.

AU - Amaral, V.

AU - Amorim, A.

AU - Aplin, S. J.

AU - Aushev, V.

AU - Bagaturia, Y.

AU - Balagura, V.

AU - Bargiotti, M.

AU - Barsukova, O.

AU - Bastos, J.

AU - Batista, J.

AU - Bauer, C.

AU - Bauer, Th S.

AU - Belkov, A.

AU - Belkov, Ar

AU - Belotelov, I.

AU - Bertin, A.

AU - Bobchenko, B.

AU - Böcker, M.

AU - Bogatyrev, A.

AU - Bohm, G.

AU - Bräuer, M.

AU - Bruinsma, M.

AU - Bruschi, M.

AU - Buchholz, P.

AU - Buran, T.

AU - Carvalho, J.

AU - Conde, P.

AU - Cruse, C.

AU - Dam, M.

AU - Danielsen, K. M.

AU - Danilov, M.

AU - De Castro, S.

AU - Deppe, H.

AU - Dong, X.

AU - Dreis, H. B.

AU - Egorytchev, V.

AU - Ehret, K.

AU - Eisele, F.

AU - Emeliyanov, D.

AU - Essenov, S.

AU - Fabbri, L.

AU - Faccioli, P.

AU - Feuerstack-Raible, M.

AU - Flammer, J.

AU - Fominykh, B.

AU - Funcke, M.

AU - Garrido, Ll

AU - Gellrich, A.

AU - Giacobbe, B.

AU - Gläß, J.

AU - Goloubkov, D.

AU - Golubkov, Y.

AU - Golutvin, A.

AU - Golutvin, I.

AU - Gorbounov, I.

AU - Gorišek, A.

AU - Gouchtchine, O.

AU - Goulart, D. C.

AU - Gradl, S.

AU - Gradl, W.

AU - Grimaldi, F.

AU - Groth-Jensen, J.

AU - Guilitsky, Yu

AU - Hansen, J. D.

AU - Hernández, J. M.

AU - Hofmann, W.

AU - Hohlmann, M.

AU - Hott, T.

AU - Hulsbergen, W.

AU - Husemann, U.

AU - Igonkina, O.

AU - Ispiryan, M.

AU - Jagla, T.

AU - Jiang, C.

AU - Kapitza, H.

AU - Karabekyan, S.

AU - Karpenko, N.

AU - Keller, S.

AU - Kessler, J.

AU - Khasanov, F.

AU - Kiryushin, Yu

AU - Kisel, I.

AU - Klinkby, E.

AU - Knöpfle, K. T.

AU - Kolanoski, H.

AU - Korpar, S.

AU - Krauss, C.

AU - Kreuzer, P.

AU - Križan, P.

AU - Krücker, D.

AU - Kupper, S.

AU - Kvaratskheliia, T.

AU - Lanyov, A.

AU - Lau, K.

AU - Lewendel, B.

AU - Lohse, T.

AU - Lomonosov, B.

AU - Männer, R.

AU - Mankel, R.

AU - Masciocchi, S.

AU - Massa, I.

AU - Matchikhilian, I.

AU - Medin, G.

AU - Medinnis, M.

AU - Mevius, M.

AU - Michetti, A.

AU - Mikhailov, Yu

AU - Mizuk, R.

AU - Muresan, R.

AU - Zur Nedden, M.

AU - Negodaev, M.

AU - Nörenberg, M.

AU - Nowak, S.

AU - De Vera, M. T.Núñez Pardo

AU - Ouchrif, M.

AU - Ould-Saada, F.

AU - Padilla, C.

AU - Peralta, D.

AU - Pernack, R.

AU - Pestotnik, R.

AU - Petersen, B. A.A.

AU - Piccinini, M.

AU - Pleier, M. A.

AU - Poli, M.

AU - Popov, V.

AU - Pose, D.

AU - Prystupa, S.

AU - Pugatch, V.

AU - Pylypchenko, Y.

AU - Pyrlik, J.

AU - Reeves, K.

AU - Reßing, D.

AU - Rick, H.

AU - Riu, I.

AU - Robmann, P.

AU - Rostovtseva, I.

AU - Rybnikov, V.

AU - Sánchez, F.

AU - Sbrizzi, A.

AU - Schmelling, M.

AU - Schmidt, B.

AU - Schreiner, A.

AU - Schröder, H.

AU - Schwanke, U.

AU - Schwartz, A. J.

AU - Schwarz, A. S.

AU - Schwenninger, B.

AU - Schwingenheuer, B.

AU - Sciacca, F.

AU - Semprini-Cesari, N.

AU - Shuvalov, S.

AU - Silva, L.

AU - Sözüer, L.

AU - Solunin, S.

AU - Somov, A.

AU - Somov, S.

AU - Spengler, J.

AU - Spighi, R.

AU - Spiridonov, A.

AU - Stanovnik, A.

AU - Starič, M.

AU - Stegmann, C.

AU - Subramania, H. S.

AU - Symalla, M.

AU - Tikhomirov, I.

AU - Titov, M.

AU - Tsakov, I.

AU - Uwer, U.

AU - Van Eldik, C.

AU - Vassiliev, Yu

AU - Villa, M.

AU - Vitale, A.

AU - Vukotic, I.

AU - Wahlberg, H.

AU - Walenta, A. H.

AU - Walter, M.

AU - Wang, J. J.

AU - Wegener, D.

AU - Werthenbach, U.

AU - Wolters, H.

AU - Wurth, R.

AU - Wurz, A.

AU - Xella-Hansen, S.

AU - Zaitsev, Yu

AU - Zavertyaev, M.

AU - Zeuner, T.

AU - Zhelezov, A.

AU - Zheng, Z.

AU - Zimmermann, R.

AU - Živko, T.

AU - Zoccoli, A.

PY - 2009/4/1

Y1 - 2009/4/1

N2 - A study of the angular distributions of leptons from decays of J/ψ's produced in p-C and p-W collisions at sqrt{s}=41.6\mbox{∼GeV} has been performed in the J/ψ Feynman-x region -0.34F <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.

AB - A study of the angular distributions of leptons from decays of J/ψ's produced in p-C and p-W collisions at sqrt{s}=41.6\mbox{∼GeV} has been performed in the J/ψ Feynman-x region -0.34F <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.

U2 - 10.1140/epjc/s10052-009-0957-7

DO - 10.1140/epjc/s10052-009-0957-7

M3 - Article

AN - SCOPUS:64849112682

SN - 1434-6044

VL - 60

SP - 517

EP - 524

JO - European Physical Journal C

JF - European Physical Journal C

IS - 4

ER -

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

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