Spin density matrix elements in exclusive $$omega $$ meson muoproduction

G. D. Alexeev; M. G. Alexeev; A. Amoroso; V. Andrieux; V. Anosov; A. Antoshkin; K. Augsten; W. Augustyniak; C. D. R. Azevedo; B. Badełek; F. Balestra; M. Ball; J. Barth; R. Beck; Y. Bedfer; J. Berenguer Antequera; J. Bernhard; M. Bodlak; F. Bradamante; A. Bressan; V. E. Burtsev; W. -C. Chang; C. Chatterjee; M. Chiosso; A. G. Chumakov; S. -U. Chung; A. Cicuttin; P. M. M. Correia; M. L. Crespo; D. D’Ago; S. Dalla Torre; S. S. Dasgupta; S. Dasgupta; I. Denisenko; O. Yu Denisov; S. V. Donskov; N. Doshita; Ch Dreisbach; W. Dünnweber; R. R. Dusaev; A. Efremov; P. D. Eversheim; P. Faccioli; M. Faessler; A. Ferrero; M. Finger; M. Finger; H. Fischer; C. Franco; J. M. Friedrich; V. Frolov; F. Gautheron; O. P. Gavrichtchouk; S. Gerassimov; J. Giarra; I. Gnesi; M. Gorzellik; A. Grasso; A. Gridin; M. Grosse Perdekamp; B. Grube; A. Guskov; D. von Harrach; R. Heitz; F. Herrmann; N. Horikawa; N. d’Hose; C. -Y. Hsieh; S. Huber; S. Ishimoto; A. Ivanov; T. Iwata; M. Jandek; V. Jary; P. Jörg; R. Joosten; E. Kabuß; F. Kaspar; A. Kerbizi; B. Ketzer; G. V. Khaustov; Yu A. Khokhlov; Yu Kisselev; F. Klein; J. H. Koivuniemi; V. N. Kolosov; K. Kondo Horikawa; I. Konorov; V. F. Konstantinov; A. M. Kotzinian; O. M. Kouznetsov; A. Koval; Z. Kral; F. Krinner; Y. Kulinich; F. Kunne; K. Kurek; R. P. Kurjata; A. Kveton; K. Lavickova; S. Levorato; Y. -S. Lian; J. Lichtenstadt; P. -J. Lin; R. Longo; V. E. Lyubovitskij; A. Maggiora; A. Magnon; N. Makins; N. Makke; G. K. Mallot; A. Maltsev; S. A. Mamon; B. Marianski; A. Martin; J. Marzec; J. Matoušek; T. Matsuda; G. Mattson; G. V. Meshcheryakov; M. Meyer; W. Meyer; Yu V. Mikhailov; M. Mikhasenko; E. Mitrofanov; N. Mitrofanov; Y. Miyachi; A. Moretti; A. Nagaytsev; C. Naim; D. Neyret; J. Nový; W. -D. Nowak; G. Nukazuka; A. S. Nunes; A. G. Olshevsky; M. Ostrick; Daniele PANZIERI; B. Parsamyan; S. Paul; H. Pekeler; J. -C. Peng; M. Pešek; D. V. Peshekhonov; M. Pešková; N. Pierre; S. Platchkov; J. Pochodzalla; V. A. Polyakov; J. Pretz; M. Quaresma; C. Quintans; C. Regali; G. Reicherz; C. Riedl; T. Rudnicki; D. I. Ryabchikov; A. Rybnikov; A. Rychter; V. D. Samoylenko; A. Sandacz; S. Sarkar; I. A. Savin; G. Sbrizzai; H. Schmieden; A. Selyunin; L. Sinha; M. Slunecka; J. Smolik; A. Srnka; D. Steffen; M. Stolarski; O. Subrt; M. Sulc; H. Suzuki; T. Szameitat; P. Sznajder; S. Tessaro; F. Tessarotto; A. Thiel; J. Tomsa; F. Tosello; A. Townsend; V. Tskhay; S. Uhl; B. I. Vasilishin; A. Vauth; B. M. Veit; J. Veloso; B. Ventura; A. Vidon; M. Virius; M. Wagner; S. Wallner; K. Zaremba; P. Zavada; M. Zavertyaev; M. Zemko; E. Zemlyanichkina; Y. Zhao; M. Ziembicki

doi:10.1140/epjc/s10052-020-08740-y

Spin density matrix elements in exclusive $$omega $$ meson muoproduction

G. D. Alexeev, M. G. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C. D. R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Berenguer Antequera, J. Bernhard, M. Bodlak, F. Bradamante, A. BressanV. E. Burtsev, W. -C. Chang, C. Chatterjee, M. Chiosso, A. G. Chumakov, S. -U. Chung, A. Cicuttin, P. M. M. Correia, M. L. Crespo, D. D’Ago, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, I. Denisenko, O. Yu Denisov, S. V. Donskov, N. Doshita, Ch Dreisbach, W. Dünnweber, R. R. Dusaev, A. Efremov, P. D. Eversheim, P. Faccioli, M. Faessler, A. Ferrero, M. Finger, M. Finger, H. Fischer, C. Franco, J. M. Friedrich, V. Frolov, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d’Hose, C. -Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, P. Jörg, R. Joosten, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G. V. Khaustov, Yu A. Khokhlov, Yu Kisselev, F. Klein, J. H. Koivuniemi, V. N. Kolosov, K. Kondo Horikawa, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y. -S. Lian, J. Lichtenstadt, P. -J. Lin, R. Longo, V. E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G. K. Mallot, A. Maltsev, S. A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, G. V. Meshcheryakov, M. Meyer, W. Meyer, Yu V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W. -D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, M. Ostrick, Daniele PANZIERI, B. Parsamyan, S. Paul, H. Pekeler, J. -C. Peng, M. Pešek, D. V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, C. Regali, G. Reicherz, C. Riedl, T. Rudnicki, D. I. Ryabchikov, A. Rybnikov, A. Rychter, V. D. Samoylenko, A. Sandacz, S. Sarkar, I. A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, T. Szameitat, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, V. Tskhay, S. Uhl, B. I. Vasilishin, A. Vauth, B. M. Veit, J. Veloso, B. Ventura, A. Vidon, M. Virius, M. Wagner, S. Wallner, K. Zaremba, P. Zavada, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, Y. Zhao, M. Ziembicki

Dipartimento di Scienze e Innovazione Tecnologica

Risultato della ricerca: Contributo su rivista › Articolo in rivista › peer review

Abstract

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised μ⁺ and μ^- beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c²< W< 17.0 GeV/c², with the average kinematics ⟨ Q²⟩ = 2.1 (GeV/c)², ⟨ W⟩ = 7.6 GeV/c², and ⟨pT2⟩=0.16 (GeV/c)². Here, Q² denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and p_T the transverse momentum of the ω meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γT∗→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive ω production.

Lingua originale	Inglese
Rivista	THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS
Volume	81
Numero di pubblicazione	2
DOI	https://doi.org/10.1140/epjc/s10052-020-08740-y
Stato di pubblicazione	Pubblicato - 2021

Accesso al documento

10.1140/epjc/s10052-020-08740-y

http://hdl.handle.net/11579/122653

Altri file e collegamenti

handle

Cita questo

Alexeev, G. D., Alexeev, M. G., Amoroso, A., Andrieux, V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Antequera, J. B., Bernhard, J., Bodlak, M., Bradamante, F., ... Ziembicki, M. (2021). Spin density matrix elements in exclusive $$omega $$ meson muoproduction. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 81(2). https://doi.org/10.1140/epjc/s10052-020-08740-y

@article{6f8f6c4017d144f28de53edd89c1a5bc,

title = "Spin density matrix elements in exclusive $$omega $$ meson muoproduction",

abstract = "We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised μ+ and μ- beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c2< W< 17.0 GeV/c2, with the average kinematics ⟨ Q2⟩ = 2.1 (GeV/c)2, ⟨ W⟩ = 7.6 GeV/c2, and ⟨pT2⟩=0.16 (GeV/c)2. Here, Q2 denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and pT the transverse momentum of the ω meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γT∗→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive ω production.",

author = "Alexeev, {G. D.} and Alexeev, {M. G.} and A. Amoroso and V. Andrieux and V. Anosov and A. Antoshkin and K. Augsten and W. Augustyniak and Azevedo, {C. D. R.} and B. Bade{\l}ek and F. Balestra and M. Ball and J. Barth and R. Beck and Y. Bedfer and Antequera, {J. Berenguer} and J. Bernhard and M. Bodlak and F. Bradamante and A. Bressan and Burtsev, {V. E.} and Chang, {W. -C.} and C. Chatterjee and M. Chiosso and Chumakov, {A. G.} and Chung, {S. -U.} and A. Cicuttin and Correia, {P. M. M.} and Crespo, {M. L.} and D. D{\textquoteright}Ago and Torre, {S. Dalla} and Dasgupta, {S. S.} and S. Dasgupta and I. Denisenko and Denisov, {O. Yu} and Donskov, {S. V.} and N. Doshita and Ch Dreisbach and W. D{\"u}nnweber and Dusaev, {R. R.} and A. Efremov and Eversheim, {P. D.} and P. Faccioli and M. Faessler and A. Ferrero and M. Finger and M. Finger and H. Fischer and C. Franco and Friedrich, {J. M.} and V. Frolov and F. Gautheron and Gavrichtchouk, {O. P.} and S. Gerassimov and J. Giarra and I. Gnesi and M. Gorzellik and A. Grasso and A. Gridin and Perdekamp, {M. Grosse} and B. Grube and A. Guskov and {von Harrach}, D. and R. Heitz and F. Herrmann and N. Horikawa and N. d{\textquoteright}Hose and Hsieh, {C. -Y.} and S. Huber and S. Ishimoto and A. Ivanov and T. Iwata and M. Jandek and V. Jary and P. J{\"o}rg and R. Joosten and E. Kabu{\ss} and F. Kaspar and A. Kerbizi and B. Ketzer and Khaustov, {G. V.} and Khokhlov, {Yu A.} and Yu Kisselev and F. Klein and Koivuniemi, {J. H.} and Kolosov, {V. N.} and Horikawa, {K. Kondo} and I. Konorov and Konstantinov, {V. F.} and Kotzinian, {A. M.} and Kouznetsov, {O. M.} and A. Koval and Z. Kral and F. Krinner and Y. Kulinich and F. Kunne and K. Kurek and Kurjata, {R. P.} and A. Kveton and K. Lavickova and S. Levorato and Lian, {Y. -S.} and J. Lichtenstadt and Lin, {P. -J.} and R. Longo and Lyubovitskij, {V. E.} and A. Maggiora and A. Magnon and N. Makins and N. Makke and Mallot, {G. K.} and A. Maltsev and Mamon, {S. A.} and B. Marianski and A. Martin and J. Marzec and J. Matou{\v s}ek and T. Matsuda and G. Mattson and Meshcheryakov, {G. V.} and M. Meyer and W. Meyer and Mikhailov, {Yu V.} and M. Mikhasenko and E. Mitrofanov and N. Mitrofanov and Y. Miyachi and A. Moretti and A. Nagaytsev and C. Naim and D. Neyret and J. Nov{\'y} and Nowak, {W. -D.} and G. Nukazuka and Nunes, {A. S.} and Olshevsky, {A. G.} and M. Ostrick and Daniele PANZIERI and B. Parsamyan and S. Paul and H. Pekeler and Peng, {J. -C.} and M. Pe{\v s}ek and Peshekhonov, {D. V.} and M. Pe{\v s}kov{\'a} and N. Pierre and S. Platchkov and J. Pochodzalla and Polyakov, {V. A.} and J. Pretz and M. Quaresma and C. Quintans and C. Regali and G. Reicherz and C. Riedl and T. Rudnicki and Ryabchikov, {D. I.} and A. Rybnikov and A. Rychter and Samoylenko, {V. D.} and A. Sandacz and S. Sarkar and Savin, {I. A.} and G. Sbrizzai and H. Schmieden and A. Selyunin and L. Sinha and M. Slunecka and J. Smolik and A. Srnka and D. Steffen and M. Stolarski and O. Subrt and M. Sulc and H. Suzuki and T. Szameitat and P. Sznajder and S. Tessaro and F. Tessarotto and A. Thiel and J. Tomsa and F. Tosello and A. Townsend and V. Tskhay and S. Uhl and Vasilishin, {B. I.} and A. Vauth and Veit, {B. M.} and J. Veloso and B. Ventura and A. Vidon and M. Virius and M. Wagner and S. Wallner and K. Zaremba and P. Zavada and M. Zavertyaev and M. Zemko and E. Zemlyanichkina and Y. Zhao and M. Ziembicki",

note = "Publisher Copyright: {\textcopyright} 2021, The Author(s).",

year = "2021",

doi = "10.1140/epjc/s10052-020-08740-y",

language = "English",

volume = "81",

journal = "THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS",

issn = "1434-6044",

number = "2",

}

Alexeev, GD, Alexeev, MG, Amoroso, A, Andrieux, V, Anosov, V, Antoshkin, A, Augsten, K, Augustyniak, W, Azevedo, CDR, Badełek, B, Balestra, F, Ball, M, Barth, J, Beck, R, Bedfer, Y, Antequera, JB, Bernhard, J, Bodlak, M, Bradamante, F, Bressan, A, Burtsev, VE, Chang, W-C, Chatterjee, C, Chiosso, M, Chumakov, AG, Chung, S-U, Cicuttin, A, Correia, PMM, Crespo, ML, D’Ago, D, Torre, SD, Dasgupta, SS, Dasgupta, S, Denisenko, I, Denisov, OY, Donskov, SV, Doshita, N, Dreisbach, C, Dünnweber, W, Dusaev, RR, Efremov, A, Eversheim, PD, Faccioli, P, Faessler, M, Ferrero, A, Finger, M, Finger, M, Fischer, H, Franco, C, Friedrich, JM, Frolov, V, Gautheron, F, Gavrichtchouk, OP, Gerassimov, S, Giarra, J, Gnesi, I, Gorzellik, M, Grasso, A, Gridin, A, Perdekamp, MG, Grube, B, Guskov, A, von Harrach, D, Heitz, R, Herrmann, F, Horikawa, N, d’Hose, N, Hsieh, C-Y, Huber, S, Ishimoto, S, Ivanov, A, Iwata, T, Jandek, M, Jary, V, Jörg, P, Joosten, R, Kabuß, E, Kaspar, F, Kerbizi, A, Ketzer, B, Khaustov, GV, Khokhlov, YA, Kisselev, Y, Klein, F, Koivuniemi, JH, Kolosov, VN, Horikawa, KK, Konorov, I, Konstantinov, VF, Kotzinian, AM, Kouznetsov, OM, Koval, A, Kral, Z, Krinner, F, Kulinich, Y, Kunne, F, Kurek, K, Kurjata, RP, Kveton, A, Lavickova, K, Levorato, S, Lian, Y-S, Lichtenstadt, J, Lin, P-J, Longo, R, Lyubovitskij, VE, Maggiora, A, Magnon, A, Makins, N, Makke, N, Mallot, GK, Maltsev, A, Mamon, SA, Marianski, B, Martin, A, Marzec, J, Matoušek, J, Matsuda, T, Mattson, G, Meshcheryakov, GV, Meyer, M, Meyer, W, Mikhailov, YV, Mikhasenko, M, Mitrofanov, E, Mitrofanov, N, Miyachi, Y, Moretti, A, Nagaytsev, A, Naim, C, Neyret, D, Nový, J, Nowak, W-D, Nukazuka, G, Nunes, AS, Olshevsky, AG, Ostrick, M, PANZIERI, D, Parsamyan, B, Paul, S, Pekeler, H, Peng, J-C, Pešek, M, Peshekhonov, DV, Pešková, M, Pierre, N, Platchkov, S, Pochodzalla, J, Polyakov, VA, Pretz, J, Quaresma, M, Quintans, C, Regali, C, Reicherz, G, Riedl, C, Rudnicki, T, Ryabchikov, DI, Rybnikov, A, Rychter, A, Samoylenko, VD, Sandacz, A, Sarkar, S, Savin, IA, Sbrizzai, G, Schmieden, H, Selyunin, A, Sinha, L, Slunecka, M, Smolik, J, Srnka, A, Steffen, D, Stolarski, M, Subrt, O, Sulc, M, Suzuki, H, Szameitat, T, Sznajder, P, Tessaro, S, Tessarotto, F, Thiel, A, Tomsa, J, Tosello, F, Townsend, A, Tskhay, V, Uhl, S, Vasilishin, BI, Vauth, A, Veit, BM, Veloso, J, Ventura, B, Vidon, A, Virius, M, Wagner, M, Wallner, S, Zaremba, K, Zavada, P, Zavertyaev, M, Zemko, M, Zemlyanichkina, E, Zhao, Y & Ziembicki, M 2021, 'Spin density matrix elements in exclusive $$omega $$ meson muoproduction', THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, vol. 81, n. 2. https://doi.org/10.1140/epjc/s10052-020-08740-y

TY - JOUR

T1 - Spin density matrix elements in exclusive $$omega $$ meson muoproduction

AU - Alexeev, G. D.

AU - Alexeev, M. G.

AU - Amoroso, A.

AU - Andrieux, V.

AU - Anosov, V.

AU - Antoshkin, A.

AU - Augsten, K.

AU - Augustyniak, W.

AU - Azevedo, C. D. R.

AU - Badełek, B.

AU - Balestra, F.

AU - Ball, M.

AU - Barth, J.

AU - Beck, R.

AU - Bedfer, Y.

AU - Antequera, J. Berenguer

AU - Bernhard, J.

AU - Bodlak, M.

AU - Bradamante, F.

AU - Bressan, A.

AU - Burtsev, V. E.

AU - Chang, W. -C.

AU - Chatterjee, C.

AU - Chiosso, M.

AU - Chumakov, A. G.

AU - Chung, S. -U.

AU - Cicuttin, A.

AU - Correia, P. M. M.

AU - Crespo, M. L.

AU - D’Ago, D.

AU - Torre, S. Dalla

AU - Dasgupta, S. S.

AU - Dasgupta, S.

AU - Denisenko, I.

AU - Denisov, O. Yu

AU - Donskov, S. V.

AU - Doshita, N.

AU - Dreisbach, Ch

AU - Dünnweber, W.

AU - Dusaev, R. R.

AU - Efremov, A.

AU - Eversheim, P. D.

AU - Faccioli, P.

AU - Faessler, M.

AU - Ferrero, A.

AU - Finger, M.

AU - Fischer, H.

AU - Franco, C.

AU - Friedrich, J. M.

AU - Frolov, V.

AU - Gautheron, F.

AU - Gavrichtchouk, O. P.

AU - Gerassimov, S.

AU - Giarra, J.

AU - Gnesi, I.

AU - Gorzellik, M.

AU - Grasso, A.

AU - Gridin, A.

AU - Perdekamp, M. Grosse

AU - Grube, B.

AU - Guskov, A.

AU - von Harrach, D.

AU - Heitz, R.

AU - Herrmann, F.

AU - Horikawa, N.

AU - d’Hose, N.

AU - Hsieh, C. -Y.

AU - Huber, S.

AU - Ishimoto, S.

AU - Ivanov, A.

AU - Iwata, T.

AU - Jandek, M.

AU - Jary, V.

AU - Jörg, P.

AU - Joosten, R.

AU - Kabuß, E.

AU - Kaspar, F.

AU - Kerbizi, A.

AU - Ketzer, B.

AU - Khaustov, G. V.

AU - Khokhlov, Yu A.

AU - Kisselev, Yu

AU - Klein, F.

AU - Koivuniemi, J. H.

AU - Kolosov, V. N.

AU - Horikawa, K. Kondo

AU - Konorov, I.

AU - Konstantinov, V. F.

AU - Kotzinian, A. M.

AU - Kouznetsov, O. M.

AU - Koval, A.

AU - Kral, Z.

AU - Krinner, F.

AU - Kulinich, Y.

AU - Kunne, F.

AU - Kurek, K.

AU - Kurjata, R. P.

AU - Kveton, A.

AU - Lavickova, K.

AU - Levorato, S.

AU - Lian, Y. -S.

AU - Lichtenstadt, J.

AU - Lin, P. -J.

AU - Longo, R.

AU - Lyubovitskij, V. E.

AU - Maggiora, A.

AU - Magnon, A.

AU - Makins, N.

AU - Makke, N.

AU - Mallot, G. K.

AU - Maltsev, A.

AU - Mamon, S. A.

AU - Marianski, B.

AU - Martin, A.

AU - Marzec, J.

AU - Matoušek, J.

AU - Matsuda, T.

AU - Mattson, G.

AU - Meshcheryakov, G. V.

AU - Meyer, M.

AU - Meyer, W.

AU - Mikhailov, Yu V.

AU - Mikhasenko, M.

AU - Mitrofanov, E.

AU - Mitrofanov, N.

AU - Miyachi, Y.

AU - Moretti, A.

AU - Nagaytsev, A.

AU - Naim, C.

AU - Neyret, D.

AU - Nový, J.

AU - Nowak, W. -D.

AU - Nukazuka, G.

AU - Nunes, A. S.

AU - Olshevsky, A. G.

AU - Ostrick, M.

AU - PANZIERI, Daniele

AU - Parsamyan, B.

AU - Paul, S.

AU - Pekeler, H.

AU - Peng, J. -C.

AU - Pešek, M.

AU - Peshekhonov, D. V.

AU - Pešková, M.

AU - Pierre, N.

AU - Platchkov, S.

AU - Pochodzalla, J.

AU - Polyakov, V. A.

AU - Pretz, J.

AU - Quaresma, M.

AU - Quintans, C.

AU - Regali, C.

AU - Reicherz, G.

AU - Riedl, C.

AU - Rudnicki, T.

AU - Ryabchikov, D. I.

AU - Rybnikov, A.

AU - Rychter, A.

AU - Samoylenko, V. D.

AU - Sandacz, A.

AU - Sarkar, S.

AU - Savin, I. A.

AU - Sbrizzai, G.

AU - Schmieden, H.

AU - Selyunin, A.

AU - Sinha, L.

AU - Slunecka, M.

AU - Smolik, J.

AU - Srnka, A.

AU - Steffen, D.

AU - Stolarski, M.

AU - Subrt, O.

AU - Sulc, M.

AU - Suzuki, H.

AU - Szameitat, T.

AU - Sznajder, P.

AU - Tessaro, S.

AU - Tessarotto, F.

AU - Thiel, A.

AU - Tomsa, J.

AU - Tosello, F.

AU - Townsend, A.

AU - Tskhay, V.

AU - Uhl, S.

AU - Vasilishin, B. I.

AU - Vauth, A.

AU - Veit, B. M.

AU - Veloso, J.

AU - Ventura, B.

AU - Vidon, A.

AU - Virius, M.

AU - Wagner, M.

AU - Wallner, S.

AU - Zaremba, K.

AU - Zavada, P.

AU - Zavertyaev, M.

AU - Zemko, M.

AU - Zemlyanichkina, E.

AU - Zhao, Y.

AU - Ziembicki, M.

PY - 2021

Y1 - 2021

N2 - We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised μ+ and μ- beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c2< W< 17.0 GeV/c2, with the average kinematics ⟨ Q2⟩ = 2.1 (GeV/c)2, ⟨ W⟩ = 7.6 GeV/c2, and ⟨pT2⟩=0.16 (GeV/c)2. Here, Q2 denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and pT the transverse momentum of the ω meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γT∗→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive ω production.

AB - We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised μ+ and μ- beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/c2< W< 17.0 GeV/c2, with the average kinematics ⟨ Q2⟩ = 2.1 (GeV/c)2, ⟨ W⟩ = 7.6 GeV/c2, and ⟨pT2⟩=0.16 (GeV/c)2. Here, Q2 denotes the virtuality of the exchanged photon, W the mass of the final hadronic system and pT the transverse momentum of the ω meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons (γT∗→VL) indicate a violation of s-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing W. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive ω production.

UR - https://iris.uniupo.it/handle/11579/122653

U2 - 10.1140/epjc/s10052-020-08740-y

DO - 10.1140/epjc/s10052-020-08740-y

M3 - Article

SN - 1434-6044

VL - 81

JO - THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS

JF - THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS

IS - 2

ER -

Spin density matrix elements in exclusive $$omega $$ meson muoproduction

Abstract

Accesso al documento

Altri file e collegamenti

Fingerprint

Cita questo