ホーム > CERN Experiments > Fixed Target Experiments > COMPASS > COMPASS Conference Proceedings > Measurement of the cross section for hard exclusive $\pi^0$ leptoproduction |
Article | |
Report number | arXiv:1903.12030 ; CERN-EP-2019-049 |
Title | Measurement of the cross section for hard exclusive $\pi^0$ leptoproduction |
Related title | Measurement of the cross section for hard exclusive $\pi^0$ muoproduction on the proton |
Author(s) |
Alexeev, M.G. (Turin U.) ; Alexeev, G.D. (Dubna, JINR) ; Amoroso, A. (Turin U. ; INFN, Turin) ; Andrieux, V. (CERN ; Illinois U., Urbana) ; Anfimov, N.V. (Dubna, JINR) ; Anosov, V. (Dubna, JINR) ; Antoshkin, A. (Dubna, JINR) ; Augsten, K. (Dubna, JINR ; CTU, Prague) ; Augustyniak, W. (NCBJ, Warsaw) ; Azevedo, C.D.R. (Aveiro U.) ; Badełek, B. (Warsaw U.) ; Balestra, F. (Turin U. ; INFN, Turin) ; Ball, M. (Bonn U., HISKP) ; Barth, J. (Bonn U., HISKP) ; Beck, R. (Bonn U., HISKP) ; Bedfer, Y. (IRFU, Saclay) ; Bernhard, J. (Mainz U., Inst. Kernphys. ; CERN) ; Bodlak, M. (Charles U.) ; Bordalo, P. (LIP, Lisbon) ; Bradamante, F. (Trieste U. ; INFN, Trieste) ; Bressan, A. (Trieste U. ; INFN, Trieste) ; Büchele, M. (Freiburg U.) ; Burtsev, V.E. (Tomsk Polytechnic U.) ; Chang, W.-C. (Taiwan, Inst. Phys.) ; Chatterjee, C. (Matrivani Inst., Calcutta) ; Chiosso, M. (Turin U. ; INFN, Turin) ; Chumakov, A.G. (Tomsk Polytechnic U.) ; Chung, S.-U. (Munich, Tech. U.) ; Cicuttin, A. (INFN, Trieste) ; Crespo, M.L. (INFN, Trieste) ; Dalla Torre, S. (INFN, Trieste) ; Dasgupta, S.S. (Matrivani Inst., Calcutta) ; Dasgupta, S. (Trieste U. ; INFN, Trieste) ; Denisov, O.Yu. (INFN, Turin) ; Dhara, L. (Matrivani Inst., Calcutta) ; Donskov, S.V. (Serpukhov, IHEP) ; Doshita, N. (Yamagata U.) ; Dreisbach, Ch. (Munich, Tech. U.) ; Dünnweber, W. ; Dusaev, R.R. (Tomsk Polytechnic U.) ; Efremov, A. (Dubna, JINR) ; Eversheim, P.D. (Bonn U., HISKP) ; Faessler, M. ; Ferrero, A. (IRFU, Saclay) ; Finger, M. (Charles U.) ; Finger, Michael, Jr. (Charles U.) ; Fischer, H. (Freiburg U.) ; Franco, C. (LIP, Lisbon) ; du Fresne von Hohenesche, N. (Mainz U., Inst. Kernphys. ; CERN) ; Friedrich, J.M. (Munich, Tech. U.) ; Frolov, V. (Dubna, JINR ; CERN) ; Fuchey, E. (IRFU, Saclay) ; Gautheron, F. (Ruhr U., Bochum ; Illinois U., Urbana) ; Gavrichtchouk, O.P. (Dubna, JINR) ; Gerassimov, S. (Lebedev Inst. ; Munich, Tech. U.) ; Giarra, J. (Mainz U., Inst. Kernphys.) ; Gnesi, I. (Turin U. ; INFN, Turin) ; Gorzellik, M. (Freiburg U.) ; Grasso, A. (Turin U. ; INFN, Turin) ; Gridin, A. (Dubna, JINR) ; Grosse Perdekamp, M. (Illinois U., Urbana) ; Grube, B. (Munich, Tech. U.) ; Guskov, A. (Dubna, JINR) ; Hahne, D. (Bonn U.) ; Hamar, G. (INFN, Trieste) ; von Harrach, D. (Mainz U., Inst. Kernphys.) ; Heitz, R. (Illinois U., Urbana) ; Herrmann, F. (Freiburg U.) ; Horikawa, N. (Nagoya U.) ; d'Hose, N. (IRFU, Saclay) ; Hsieh, C.-Y. (Taiwan, Inst. Phys.) ; Huber, S. (Munich, Tech. U.) ; Ishimoto, S. (Yamagata U.) ; Ivanov, A. (Turin U. ; INFN, Turin) ; Iwata, T. (Yamagata U.) ; Jandek, M. (CTU, Prague) ; Jary, V. (CTU, Prague) ; Joosten, R. (Bonn U., HISKP) ; Jörg, P. (Freiburg U.) ; Juraskova, K. (CTU, Prague) ; Kabuß, E. (Mainz U., Inst. Kernphys.) ; Kaspar, F. (Munich, Tech. U.) ; Kerbizi, A. (Trieste U. ; INFN, Trieste) ; Ketzer, B. (Bonn U., HISKP) ; Khaustov, G.V. (Serpukhov, IHEP) ; Khokhlov, Yu.A. (Serpukhov, IHEP) ; Kisselev, Yu. (Dubna, JINR) ; Klein, F. (Bonn U.) ; Koivuniemi, J.H. (Ruhr U., Bochum ; Illinois U., Urbana) ; Kolosov, V.N. (Serpukhov, IHEP) ; Kondo Horikawa, K. (Yamagata U.) ; Konorov, I. (Lebedev Inst. ; Munich, Tech. U.) ; Konstantinov, V.F. (Serpukhov, IHEP) ; Kotzinian, A.M. (INFN, Turin) ; Kouznetsov, O.M. (Dubna, JINR) ; Kral, Z. (Charles U.) ; Krämer, M. (Munich, Tech. U.) ; Krinner, F. (Munich, Tech. U.) ; Kroumchtein, Z.V. (Dubna, JINR) ; Kulinich, Y. (Illinois U., Urbana) ; Kunne, F. (IRFU, Saclay) ; Kurek, K. (NCBJ, Warsaw) ; Kurjata, R.P. (Warsaw U. of Tech.) ; Kveton, A. (CTU, Prague) ; Levorato, S. (INFN, Trieste) ; Lian, Y.-S. (Taiwan, Inst. Phys.) ; Lichtenstadt, J. (Tel Aviv U.) ; Lin, P.-J. (IRFU, Saclay) ; Longo, R. (Illinois U., Urbana) ; Lyubovitskij, V.E. (Tomsk Polytechnic U.) ; Maggiora, A. (INFN, Turin) ; Magnon, A. (Illinois U., Urbana) ; Makins, N. (Illinois U., Urbana) ; Makke, N. (INFN, Trieste) ; Mallot, G.K. (CERN) ; Mamon, S.A. (Tomsk Polytechnic U.) ; Marianski, B. (NCBJ, Warsaw) ; Martin, A. (Trieste U. ; INFN, Trieste) ; Marzec, J. (Warsaw U. of Tech.) ; Matoušek, J. (Trieste U. ; INFN, Trieste ; Charles U.) ; Matsuda, T. (Miyazaki U.) ; Meshcheryakov, G.V. (Dubna, JINR) ; Meyer, M. (Illinois U., Urbana ; IRFU, Saclay) ; Meyer, W. (Ruhr U., Bochum) ; Mikhailov, Yu.V. (Serpukhov, IHEP) ; Mikhasenko, M. (Bonn U., HISKP) ; Mitrofanov, E. (Dubna, JINR) ; Mitrofanov, N. (Dubna, JINR) ; Miyachi, Y. (Yamagata U.) ; Moretti, A. (Trieste U. ; INFN, Trieste) ; Naim, C. (IRFU, Saclay) ; Nagaytsev, A. (Dubna, JINR) ; Neyret, D. (IRFU, Saclay) ; Nový, J. (CTU, Prague ; CERN) ; Nowak, W.-D. (Mainz U., Inst. Kernphys.) ; Nukazuka, G. (Yamagata U.) ; Nunes, A.S. (LIP, Lisbon) ; Olshevsky, A.G. (Dubna, JINR) ; Ostrick, M. (Mainz U., Inst. Kernphys.) ; Panzieri, D. (INFN, Turin) ; Parsamyan, B. (Turin U. ; INFN, Turin) ; Paul, S. (Munich, Tech. U.) ; Peng, J.-C. (Illinois U., Urbana) ; Pereira, F. (Aveiro U.) ; Pešek, M. (Charles U.) ; Peshekhonov, D.V. (Dubna, JINR) ; Pešková, M. (Charles U.) ; Pierre, N. (Mainz U., Inst. Kernphys. ; IRFU, Saclay) ; Platchkov, S. (IRFU, Saclay) ; Pochodzalla, J. (Mainz U., Inst. Kernphys.) ; Polyakov, V.A. (Serpukhov, IHEP) ; Pretz, J. (Bonn U.) ; Quaresma, M. (Taiwan, Inst. Phys.) ; Quintans, C. (LIP, Lisbon) ; Ramos, S. (LIP, Lisbon) ; Regali, C. (Freiburg U.) ; Reicherz, G. (Ruhr U., Bochum) ; Riedl, C. (Illinois U., Urbana) ; Ryabchikov, D.I. (Serpukhov, IHEP ; Munich, Tech. U.) ; Rybnikov, A. (Dubna, JINR) ; Rychter, A. (Warsaw U. of Tech.) ; Samoylenko, V.D. (Serpukhov, IHEP) ; Sandacz, A. (NCBJ, Warsaw) ; Sarkar, S. (Matrivani Inst., Calcutta) ; Savin, I.A. (Dubna, JINR) ; Sbrizzai, G. (Trieste U. ; INFN, Trieste) ; Schmieden, H. (Bonn U.) ; Selyunin, A. (Dubna, JINR) ; Silva, L. (LIP, Lisbon) ; Sinha, L. (Matrivani Inst., Calcutta) ; Slunecka, M. (Dubna, JINR) ; Smolik, J. (Dubna, JINR) ; Srnka, A. (Inst. Sci. Instruments, Brno) ; Steffen, D. (CERN ; Munich, Tech. U.) ; Stolarski, M. (LIP, Lisbon) ; Subrt, O. (CERN ; CTU, Prague) ; Sulc, M. (Liberec Tech. U.) ; Suzuki, H. (Yamagata U.) ; Szabelski, A. (Trieste U. ; INFN, Trieste ; NCBJ, Warsaw) ; Szameitat, T. (Freiburg U.) ; Sznajder, P. (NCBJ, Warsaw) ; Tessaro, S. (INFN, Trieste) ; Tessarotto, F. (INFN, Trieste) ; Thiel, A. (Bonn U., HISKP) ; Tomsa, J. (Charles U.) ; Tosello, F. (INFN, Turin) ; Tskhay, V. (Lebedev Inst.) ; Uhl, S. (Munich, Tech. U.) ; Vasilishin, B.I. (Tomsk Polytechnic U.) ; Vauth, A. (Bonn U. ; CERN) ; Veit, B.M. (Mainz U., Inst. Kernphys. ; CERN) ; Veloso, J. (Aveiro U.) ; Vidon, A. (IRFU, Saclay) ; Virius, M. (CTU, Prague) ; Wagner, M. (Bonn U., HISKP) ; Wallner, S. (Munich, Tech. U.) ; Wilfert, M. (Mainz U., Inst. Kernphys.) ; Zaremba, K. (Warsaw U. of Tech.) ; Zavada, P. (Dubna, JINR) ; Zavertyaev, M. (Lebedev Inst.) ; Zemlyanichkina, E. (Dubna, JINR) ; Zhao, Y. (INFN, Trieste) ; Ziembicki, M. (Warsaw U. of Tech.) |
Publication | 2020-06-10 |
Imprint | 2019-03-28 |
Number of pages | 9 |
Note | 9 pages, 5 figures |
In: | Phys. Lett. B 805 (2020) 135454 |
DOI | 10.1016/j.physletb.2020.135454 |
Subject category | hep-ex ; Particle Physics - Experiment |
Accelerator/Facility, Experiment | CERN SPS ; COMPASS NA58 |
Abstract | We report on a measurement of hard exclusive $\pi^0$ muoproduction on the proton by COMPASS using 160 GeV/$c$ polarised $\mu^+$ and $\mu^-$ beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured $\mu^+$ and $\mu^-$ cross sections, the virtual-photon proton cross section is determined as a function of the squared four-momentum transfer between initial and final proton in the range $0.08\,(\text{GeV/}c)^2 < |t| < 0.64\,(\text{GeV/}c)^2$. The average kinematics of the measurement are $\langle Q^2 \rangle =2.0\; {(\text{GeV}/c)^2}$, $\langle \nu \rangle = 12.8\; {\text{GeV}}$, $\langle x_{Bj} \rangle = 0.093 $ and $\langle -t \rangle = 0.256\; {(\text{GeV}/c)^2} $. Fitting the azimuthal dependence reveals a combined contribution by transversely and longitudinally polarised photons of $(8.1 \ \pm \ 0.9_{\text{stat}}{}_{- \ 1.0}^{+ \ 1.1}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$, as well as transverse-transverse and longitudinal-transverse interference contributions of $(-6.0 \pm 1.3_{\text{stat}}{}_{- \ 0.7}^{+ \ 0.7}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$ and $(1.4 \pm 0.5_{\text{stat}}{}_{- \ 0.2}^{+ \ 0.3}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$, respectively. Our results provide important input for modelling Generalised Parton Distributions. In the context of the phenomenological Goloskokov-Kroll model, the statistically significant transverse-transverse interference contribution constitutes clear experimental evidence for the chiral-odd GPD $\overline{E}_T$. |
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