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

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

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 2.3×105 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",

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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