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11 results on '"Steffen, D."'

1. Triangle Singularity as the Origin of the $a_1(1420)$

Author

Alexeev, G. D., Alexeev, M. G., Amoroso, A., Andrieux, V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Antequera, J. Berenguer, Bernhard, J., Bodlak, M., Bradamante, F., Bressan, A., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Correia, P. M. M., Crespo, M. L., D'Ago, D., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisenko, I., Denisov, O. Yu., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faccioli, P., Faessler, M., Finger, M., Finger jr., M., Fischer, H., Franco, C., Friedrich, J. M., Frolov, V., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, 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, T., Joosten, R., Joerg, P., Kabuss, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Koval, A., Kral, Z., Krinner, F., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Lavickova, K., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Maltsev, A., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, T., Mattson, G., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Naim, C., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevskiy, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Pekeler, H., Peng, J. -C., Pesek, M., Peshekhonov, D. V., Peskova, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Reicherz, G., Riedl, C., Rudnicki, T., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Townsend, A., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., 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., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, 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., Berenguer Antequera, J., Bernhard, J., Bodlak, M., Bradamante, F., Bressan, A., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Correia, P. M. M., Crespo, M. L., D’Ago, D., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisenko, I., Denisov, O. Yu., Donskov, S. V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faccioli, P., Faessler, M., Finger, M., Fischer, H., Franco, C., Friedrich, J. M., Frolov, V., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., 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., Joosten, R., Jörg, P., Kabuß, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo Horikawa, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Koval, A., Kral, Z., Krinner, F., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Lavickova, K., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Maltsev, A., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, T., Mattson, G., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Naim, C., Neyret, D., Nový, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Pekeler, H., Peng, J. -C., Pešek, M., Peshekhonov, D. V., Pešková, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Reicherz, G., Riedl, C., Rudnicki, T., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Townsend, A., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Ventura, B., Vidon, A., Virius, M., Wagner, M., Wallner, S., Zaremba, K., Zavada, P., Zavertyaev, M., Zemko, M., Zemlyanichkina, E., Zhao, Y., and Ziembicki, M.

Subjects
isovector, partial wave, meson: exotic, FOS: Physical sciences, axial-vector, quantum number, COMPASS, singularity, High Energy Physics - Experiment, High Energy Physics - Phenomenology, hadron physics, resonance, High Energy Physics - Experiment (hep-ex), compass, High Energy Physics - Phenomenology (hep-ph), resonance, quality, hadron physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, ground state, structure, compa, Particle Physics - Experiment
Abstract

The COMPASS experiment recently discovered a new isovector resonance-like signal with axial-vector quantum numbers, the $a_1(1420)$, decaying to $f_0(980)\pi$. With a mass too close to and a width smaller than the axial-vector ground state $a_1(1260)$, it was immediately interpreted as a new light exotic meson, similar to the $X$, $Y$, $Z$ states in the hidden-charm sector. We show that a resonance-like signal fully matching the experimental data is produced by the decay of the $a_1(1260)$ resonance into $K^\ast(\to K\pi)\bar{K}$ and subsequent rescattering through a triangle singularity into the coupled $f_0(980)\pi$ channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having less parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonance-like structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect., Comment: 7 pages, 5 figures

Published
2021

2. Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering

Author

Aghasyan, M., Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buechele, M., Burtsev, V. E., Capozza, L., Chang, W. -C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Curiel, Q., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., von Hohenesche, N. du Fresne, Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heinsius, F. H., Heitz, R., Herrmann, F., Horikawa, N., d'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jary, V., Joosten, R., Joerg, P., Kabuss, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Koenigsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kraemer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peskova, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schoenning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veloso, J., Vidon, A., Virius, M., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., Ziembicki, M., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Aghasyan, M., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Büchele, M., Burtsev, V. E., Capozza, L., Chang, W. -C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Curiel, Q., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heinsius, F. H., Heitz, R., Herrmann, F., Horikawa, N., D’Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jary, V., Joosten, R., Jörg, P., Kabuß, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Königsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Krämer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Nový, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pešek, M., Pešková, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schönning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veloso, J., Vidon, A., Virius, M., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Ziembicki, M., Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), and Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay

Subjects
CERN Lab, ComputerSystemsOrganization_COMPUTERSYSTEMIMPLEMENTATION, MULTIPLICITIES, dimension: 3, PT DEPENDENT, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, FOS: Physical sciences, ComputerApplications_COMPUTERSINOTHERSYSTEMS, target: isoscalar, muon deuteron: deep inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, transverse momentum dependence, hadron: transverse momentum, SIDIS, COMPASS, GeneralLiterature_MISCELLANEOUS, High Energy Physics - Experiment, scaling: Bjorken, Subatomär fysik, charged particle: multiplicity, High Energy Physics - Experiment (hep-ex), [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], mass: hadronic, Subatomic Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Physics - Experiment, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), quantum chromodynamics: perturbation theory, Nuclear Experiment, DIS, hep-ex, hadron: multiplicity, effect: nonperturbative, perturbation theory: higher-order, CERN SPS, photon: energy, semi-inclusive reaction, ComputingMethodologies_PATTERNRECOGNITION, kinematics, High Energy Physics::Experiment, Particle Physics - Experiment, experimental results, photon: virtual
Abstract

A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality $Q^{2}>1$ (GeV/$c$)$^2$, invariant mass of the hadronic system $W > 5$ GeV/$c^2$, Bjorken scaling variable in the range $0.003 < x < 0.4$, fraction of the virtual photon energy carried by the hadron in the range $0.2 < z < 0.8$, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/$c)^2 < P_{\rm{hT}}^{2} < 3$ (GeV/$c$)$^2$. The multiplicities are presented as a function of $P_{\rm{hT}}^{2}$ in three-dimensional bins of $x$, $Q^2$, $z$ and compared to previous semi-inclusive measurements. We explore the small-$P_{\rm{hT}}^{2}$ region, i.e. $P_{\rm{hT}}^{2} < 1$ (GeV/$c$)$^2$, where hadron transverse momenta are expected to arise from non-perturbative effects, and also the domain of larger $P_{\rm{hT}}^{2}$, where contributions from higher-order perturbative QCD are expected to dominate. The multiplicities are fitted using a single-exponential function at small $P_{\rm{hT}}^{2}$ to study the dependence of the average transverse momentum $\langle P_{\rm{hT}}^{2}\rangle$ on $x$, $Q^2$ and $z$. The power-law behaviour of the multiplicities at large $P_{\rm{hT}}^{2}$ is investigated using various functional forms. The fits describe the data reasonably well over the full measured range., 28 pages, 20 figures

Published
2018

3. Measurement of the cross section for hard exclusive $\pi^0$ leptoproduction

Author

Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buechele, M., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Finger jr., M., Fischer, H., Franco, C., von Hohenesche, N. du Fresne, Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, Grube, B., Guskov, A., Hahne, D., Hamar, G., 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, T., Joosten, R., Joerg, P., Juraskova, K., Kabuss, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kraemer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Naim, C., Nagaytsev, A., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevskiy, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peshekhonov, D. V., Peskova, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Silva, L., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Vidon, A., Virius, M., Wagner, M., Wallner, S., Wilfert, M., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhao, Y., Ziembicki, M., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and COMPASS

Subjects
exclusive reaction, generalized parton distribution, hep-ex, muon: beam, polarization: longitudinal, interference, cross section: measured, COMPASS, High Energy Physics - Experiment, photon: polarization, angular dependence, pi0: leptoproduction, hydrogen: liquid: target, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], polarization: transverse, Particle Physics - Experiment, experimental results
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 $\overline{E}_T$., Comment: 9 pages, 5 figures

Published
2019

4. Longitudinal double-spin asymmetry $A_1^{\rm p}$ and spin-dependent structure function $g_1^{\rm p}$ of the proton at small values of $x$ and $Q^2$

Author

Aghasyan, M., Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buechele, M., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., von Hohenesche, N. du Fresne, Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heinsius, F. H., Heitz, R., Herrmann, F., Horikawa, N., d'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jary, V., Joosten, R., Joerg, P., Kabuss, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Koenigsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kraemer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peskova, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schoenning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veloso, J., Vidon, A., Virius, M., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., Ziembicki, M., Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Laboratoire AIM, Université Paris Diderot - Paris 7 ( UPD7 ) -Centre d'Etudes de Saclay, COMPASS, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), and Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112))

Subjects
small-x, CERN Lab, [formula omitted], FOS: Physical sciences, sum rule: Bjorken, structure function: spin, spin: dependence, COMPASS, beam: energy, High Energy Physics - Experiment, x-dependence, High Energy Physics - Experiment (hep-ex), p: spin, momentum transfer: low, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], p: structure function, Nuclear Experiment, A1, hep-ex, muon: beam, spin: effect, photon, Inelastic muon scattering, CERN SPS, Low [formula omitted], Low Q2, Low x, Spin structure function, g1, muon p: deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment, nucleon: spin, muon: polarized beam, spin: longitudinal, statistical, spin: asymmetry, Particle Physics - Experiment, experimental results
Abstract

We present a precise measurement of the proton longitudinal double-spin asymmetry $A_1^{\rm p}$ and the proton spin-dependent structure function $g_1^{\rm p}$ at photon virtualities $0.006~({\rm GeV}/c)^2, Comment: 19 pages, 7 figures

Published
2018

5. Search for muoproduction of $X (3872)$ at COMPASS and indication of a new state $\widetilde{X}(3872)$

Author

COMPASS Collaboration, Aghasyan, M., Augsten, K., Kondo, K., Königsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Krämer, M., Kremser, P., Krinner, F., Augustyniak, W., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Austregesilo, A., Levorato, S., Lian, Y.-S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Azevedo, C. D. R., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Badełek, B., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Nagaytsev, A., Nerling, F., Neyret, D., Nový, J., Nowak, W.-D., Balestra, F., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J.-C., Pereira, F., Ball, M., Pešek, M., Pešková, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, Jörg, Quaresma, M., Quintans, C., Barth, J., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Beck, R., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schönning, K., Bedfer, Y., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Akhunzyanov, R., Bernhard, J., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Bicker, K., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veloso, J., Vidon, A., Virius, M., Wallner, S., Bielert, E. R., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., Ziembicki, M., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Büchele, M., Burtsev, V. E., Alexeev, M. G., Chang, W.-C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S.-U., Cicuttin, A., Crespo, M. L., Dalla Torre, S., Dasgupta, S. S., Alexeev, G. D., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Amoroso, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Andrieux, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Anfimov, N. V., Grosse-Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heinsius, F. H., Heitz, R., Herrmann, F., Anosov, V., Horikawa, N., d'Hose, N., Hsieh, C.-Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jary, V., Joosten, R., Antoshkin, A., Jörg, P., Kabuß, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and COMPASS

Subjects
two-pion [mass spectrum], muon nucleus: exclusive reaction, FOS: Physical sciences, leptoproduction [X(3872)], COMPASS, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), X(3872), hadronic decay [X(3872)], mass spectrum: two-pion, Tetraquark, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, X(3872): hadronic decay, muon+: beam, Nuclear Experiment, muon+ nucleus: scattering, M176M, hep-ex, X(3872): leptoproduction, beam [muon+], CERN SPS, exclusive production, channel cross section: branching ratio: measured, Photoproduction, +J%2Fpsi%283100%29+2pi%22">X(3872) --> J/psi(3100) 2pi, branching ratio: measured [channel cross section], exclusive reaction [muon nucleus], High Energy Physics::Experiment, Exotic charmonia, scattering [muon+ nucleus], hadron, statistical, Particle Physics - Experiment, experimental results
Abstract

We have searched for exclusive production of exotic charmonia in the reaction $\mu^+~N \rightarrow \mu^+ (J\!/\!\psi\pi^+\pi^-)\pi^{\pm}~N'$ using COMPASS data collected with incoming muons of 160 GeV/$c$ and 200 GeV/$c$ momentum. In the $J\!/\!\psi\pi^+\pi^-$ mass distribution we observe a signal with a statistical significance of 4.1 $\sigma$. Its mass and width are consistent with those of the $X(3872)$. The shape of the $\pi^+\pi^-$ mass distribution from the observed decay into $J\!/\!\psi\pi^+\pi^-$ shows disagreement with previous observations for $X(3872)$. The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of $X(3872)$ with $C = -1$ predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into $J\!/\!\psi\pi^+\pi^-$ is determined to be 71$\pm$28(stat)$\pm$39(syst) pb., Comment: 12 pages, 6 figures

Published
2018

6. Search for muoproduction of X (3872) at COMPASS and indication of a new state $\widetilde{X}$(3872)

Author

Aghasyan, M., Akhunzyanov, R., Alexeev, M.G., Alexeev, G.D., Amoroso, A., Andrieux, V., Anfimov, N.V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C.D.R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E.R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Büchele, M., Burtsev, V.E., Chang, W.-C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A.G., Chung, S.-U., Cicuttin, A., Crespo, M.L., Dalla Torre, S., Dasgupta, S.S., Denisov, O.Yu., Dhara, L., Donskov, S.V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R.R., Dziewiecki, M., Efremov, A., Eversheim, P.D., Faessler, M., Ferrero, A., Finger, Michael, Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J.M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O.P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., Von Harrach, D., Heinsius, F.H., HEITZ, R., Herrmann, F., Horikawa, N., D'Hose, N., Hsieh, C.-Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jary, V., Joosten, R., Jörg, P., Kabuß, E., Kerbizi, A., Ketzer, B., Khaustov, G.V., Khokhlov, Yu.A., Kisselev, Yu., Klein, F., Koivuniemi, J.H., Kolosov, V.N., Kondo, K., Königsmann, K., Konorov, I., Konstantinov, V.F., Kotzinian, A.M., Kouznetsov, O.M., Kral, Z., Krämer, M., Kremser, P., Krinner, F., Kroumchtein, Z.V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R.P., Kuznetsov, I.I., Kveton, A., Lednev, A.A., Levchenko, E.A., Levillain, M., Levorato, S., Lian, Y.-S., Lichtenstadt, J., Longo, R., Lyubovitskij, V.E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G.K., Mamon, S.A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G.V., Meyer, M., Meyer, W., Mikhailov, Yu.V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Nagaytsev, A., Nerling, F., Neyret, D., Nový, J., Nowak, W.-D., Nukazuka, G., Nunes, A.S., Olshevsky, A.G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J.-C., Pereira, F., Pešek, M., Pešková, M., Peshekhonov, D.V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V.A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N.S., Ryabchikov, D.I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V.D., Sandacz, A., Santos, C., Sarkar, S., Savin, I.A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schönning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B.I., Vauth, A., Veloso, J., Vidon, A., Virius, M., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., Ziembicki, M., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and COMPASS

Subjects
X(3872), Automatic Keywords, charmonium, Tetraquark, muon, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Exotic charmonia, branching ratio, tetraquark: model, COMPASS, statistical, pi+ pi-: mass spectrum, photoproduction
Abstract

International audience; We have searched for exclusive production of exotic charmonia in the reaction μ+N→μ+(J/ψπ+π−)π±N′ using COMPASS data collected with incoming muons of 160 GeV/ c and 200 GeV/ c momentum. In the J/ψπ+π− mass distribution we observe a signal with a statistical significance of 4.1 σ . Its mass and width are consistent with those of the X(3872) . The shape of the π+π− mass distribution from the observed decay into J/ψπ+π− shows disagreement with previous observations for X(3872) . The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of X(3872) with C=−1 predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into J/ψπ+π− is determined to be 71±28(stat)±39(syst) pb.

Published
2018

7. Light isovector resonances in $\pi^- p \to \pi^-\pi^-\pi^+ p$ at 190 GeV/${\it c}$

Author

Aghasyan, M., Alexeev, M. G., Austregesilo, A., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kraemer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Azevedo, C. D. R., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Levorato, S., Lian, Y.-S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Badełek, B., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Balestra, F., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Ball, M., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Nový, J., Nowak, W.-D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Barth, J., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J.-C., Pereira, F., Pešek, M., Pešková, M., Peshekhonov, D. V., Pierre, N., Beck, R., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, Jörg, Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Bedfer, Y., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Bernhard, J., Sawada, T., Sbrizzai, G., Schiavon, P., Schlüter, T., Schmeing, S., Schmieden, H., Seder, E., Selyunin, A., Silva, L., Sinha, L., Bicker, K., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Alexeev, G. D., Bielert, E. R., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Birsa, R., Vasilishin, B. I., Vauth, A., Büchele, M., Veloso, J., Vidon, A., Virius, M., Wallner, S., Wilfert, M., Wolbeek, J. ter, Zaremba, K., Bodlak, M., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Ziembicki, M., Schönning, K., Haas, F., COMPASS Collaboration, Bordalo, P., Bradamante, F., Bressan, A., Buechele, M., Burtsev, V. E., Chang, W.-C., Chatterjee, C., Amoroso, A., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S.-U., Cicuttin, A., Crespo, M. L., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, Oleg Yu., Andrieux, V., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Anfimov, N. V., Ferrero, A., Finger, M., Finger Jr., M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, Jan M., Frolov, V., Fuchey, E., Gautheron, F., Anosov, V., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse-Perdekamp, M., Grube, Boris, Grussenmeyer, T., Antoshkin, A., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., d'Hose, N., Hsieh, C.-Y., Huber, S., Augsten, K., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jary, V., Joosten, R., Joerg, P., Juraskova, K., Kabuss, E., Kerbizi, A., Augustyniak, W., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), and Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay

Subjects
M230M, M185M, resonance: isovector, M012.11, M012.12, M012M1, M161M, multiple production [pi], momentum transfer dependence, M017.6, M161W, (pi+ 2pi-) [mass spectrum], COMPASS, M017.5, M230W, High Energy Physics - Experiment, M185W, M017:Desig=5, M017:Desig=6, mass: width, M012:Desig=12, M012:Desig=11, excited state, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], a4(2040): hadronic decay, Particle Physics Experiments, M017M, meson: ground state, M239M, M164M, M075M, hadronic decay [a2(1320)], 190 GeV/c, mass spectrum: (pi+ 2pi-), parity [spin], hep-ph, M075W, Breit-Wigner, M164W, hadroproduction [meson resonance], mass dependence, inclusive reaction [pi- p], M111.5, High Energy Physics - Phenomenology, branching ratio, ground state [meson], Particle Physics - Experiment, beam [pi-], M034M, M010M, diffraction: dissociation, pi- p: inclusive reaction, M239:Desig=1, M034W, quantum number, M010W, pi(1800), width [mass], M012W1, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], recoil, ddc:530, hadronic decay [a4(2040)], Particle Physics - Phenomenology, M239W, M111:Desig=5, pi-: beam, M239.1, hep-ex, M017W, pi: multiple production, hadron spectroscopy, M162M, isovector [resonance], partial wave analysis, CERN SPS, a2(1320): hadronic decay, M162W, meson resonance: hadroproduction, spin: parity, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], pi2(1880), pi2(1670), [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], dissociation [diffraction], experimental results
Abstract

We have performed the most comprehensive resonance-model fit of $\pi^-\pi^-\pi^+$ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction $\pi^- + p \to \pi^-\pi^-\pi^+ + p_\text{recoil}$ with a 190 GeV/$c$ pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, $0.5 < m_{3\pi} < 2.5$ GeV/$c^2$, and simultaneously in 11 bins of the reduced four-momentum transfer squared, $0.1 < t' < 1.0$ $($GeV$/c)^2$, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with $J^{PC} = 0^{-+}$, $1^{++}$, $2^{++}$, $2^{-+}$, $4^{++}$, and spin-exotic $1^{-+}$ quantum numbers. The model contains the well-known resonances $\pi(1800)$, $a_1(1260)$, $a_2(1320)$, $\pi_2(1670)$, $\pi_2(1880)$, and $a_4(2040)$. In addition, it includes the disputed $\pi_1(1600)$, the excited states $a_1(1640)$, $a_2(1700)$, and $\pi_2(2005)$, as well as the resonancelike $a_1(1420)$. We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 $t'$ bins. We extract the relative branching fractions of the $\rho(770) \pi$ and $f_2(1270) \pi$ decays of $a_2(1320)$ and $a_4(2040)$, where the former one is measured for the first time. In a novel approach, we extract the $t'$ dependence of the intensity of the resonances and of their phases. The $t'$ dependence of the intensities of most resonances differs distinctly from the $t'$ dependence of the nonresonant components. For the first time, we determine the $t'$ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances., Comment: 224 pages, 172 figures

Published
2018

8. Exclusive $\omega$ meson muoproduction on transversely polarised protons

Author

Adolph, C., Agarwala, J., Aghasyan, M., Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badelek, B., Balestra, F., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bisplinghoff, J., Bodlak, M., Boer, M., Bordalo, P., Bradamante, F., Braun, C., Bressan, A., Buechele, M., Chang, W. -C., Chatterjee, C., Chiosso, M., Choi, I., Chung, S. -U., Cicuttin, A., Crespo, M. L., Curiel, Q., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Duic, V., Duennweber, W., Dziewiecki, M., Efremov, A., Eversheim, P. D., Eyrich, W., Faessler, M., Ferrero, A., Finger, M., Finger jr., M., Fischer, H., Franco, C., von Hohenesche, N. du Fresne, Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giordano, F., Gnesi, I., Gorzellik, M., Grabmueller, S., Grasso, A., Perdekamp, M. Grosse, Grube, B., Grussenmeyer, T., Guskov, A., Haas, F., Hahne, D., von Harrach, D., Hashimoto, R., Heinsius, F. H., Heitz, R., Herrmann, F., Hinterberger, F., Horikawa, N., dHose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Yu., Iwata, T., Jahn, R., Jary, V., Joosten, R., Joerg, P., Kabuss, E., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Klimaszewski, K., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Koenigsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kraemer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Lednev, A. A., Lehmann, A., Levillain, M., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Marchand, C., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Michigami, T., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Montuenga, P., Nagaytsev, A., Nerling, F., Neyret, D., Nikolaenko, V. I., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Roskot, M., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schoenning, K., Schopferer, S., Seder, E., Selyunin, A., Shevchenko, O. Yu., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Sozzi, F., Srnka, A., Steffen, D., Stolarski, M., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Takekawa, S., Tasevsky, M., Tessaro, S., Tessarotto, F., Thibaud, F., Tosello, F., Tskhay, V., Uhl, S., Veloso, J., Virius, M., Vondra, J., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Ziembicki, M., Zink, A., Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Observatoire de la Côte d'Azur (OCA), Centre National de la Recherche Scientifique (CNRS), COMPASS, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) ( DPHN ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Observatoire de la Côte d'Azur ( OCA ), and Centre National de la Recherche Scientifique ( CNRS )

Subjects
Statistics::Theory, generalized parton distribution, angular distribution: asymmetry, muon nucleus: nuclear reaction, parton: distribution function, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, muon+ p: scattering, COMPASS, High Energy Physics - Experiment, scaling: Bjorken, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Physics - Experiment, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, omega(783): leptoproduction, transversity, form factor: transition, hep-ex, 160 GeV/c, quark: angular momentum, polarized target: transverse, photon, momentum transfer, omega(783): exclusive production, nucleon: helicity, High Energy Physics::Experiment, spin: asymmetry, Particle Physics - Experiment, omega(783): transverse momentum, experimental results
Abstract

Exclusive production of $\omega$ mesons was studied at the COMPASS experiment by scattering $160~\mathrm{GeV}/\mathit{c}$ muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality $1~(\mathrm{GeV}/\mathit{c})^2 < Q^2 < 10~(\mathrm{GeV}/\mathit{c})^2$, Bjorken scaling variable $0.003 < x_{\mathit{Bj}} < 0.3$ and transverse momentum squared of the $\omega$ meson $0.05~(\mathrm{GeV}/\mathit{c})^2 < p_{T}^{2} < 0.5~(\mathrm{GeV}/\mathit{c})^2$. The measured asymmetries are sensitive to the nucleon helicity-flip Generalised Parton Distributions (GPD) $E$ that are related to the orbital angular momentum of quarks, the chiral-odd GPDs $H_{T}$ that are related to the transversity Parton Distribution Functions, and the sign of the $\pi\omega$ transition form factor. The results are compared to recent calculations of a GPD-based model., Comment: 23 pages, 9 figures

Published
2017

10. First measurement of the Sivers asymmetry for gluons using SIDIS data

Author

S. V. Donskov, O.Yu. Denisov, M. Pešek, C. Regali, K. Königsmann, Aram Kotzinian, A.S. Nunes, D.V. Peshekhonov, D. Panzieri, Janusz Marzec, T. Grussenmeyer, P.D. Eversheim, R. Beck, A. Kerbizi, M. Wilfert, J. ter Wolbeek, H. Suzuki, C.D.R. Azevedo, A. Maggiora, G.V. Meshcheryakov, Yu. V. Mikhailov, S. Sirtl, C. Adolph, Arseniy Rybnikov, S. Gerassimov, N. Horikawa, F. Giordano, A. Grasso, W.-D. Nowak, F. Tosello, S. Tessaro, F. Tessarotto, Laura Gonzalez Silva, Yu. Kisselev, D. Hahne, J. Nový, R. Salac, M. Ostrick, M. Stolarski, I. Gnesi, Andrew Ivanov, E.R. Bielert, A.G. Olshevsky, F. Krinner, A. Rychter, S.S. Dasgupta, R. Akhunzyanov, Yu.A. Khokhlov, T. Szameitat, R. Longo, G. Nukazuka, P. Kremser, G. D. Alexeev, D.I. Ryabchikov, W. Dünnweber, M. Levillain, C.-Y. Hsieh, S.-U. Chung, E. Seder, M. Krämer, V. Frolov, Soumen Paul, M. V. Zavertyaev, V. Anosov, Franco Bradamante, D. von Harrach, V.N. Kolosov, K. Schönning, F. Thibaud, J. Barth, Celso Augusto Guimarães Santos, M. Ziembicki, T. Sawada, I. J. Choi, E. M. Kabuß, A. Magnon, C. Quintans, M. Tasevsky, Gerhard K. Mallot, E. Mitrofanov, R. Heitz, Miroslav Sulc, I.A. Savin, P. Schiavon, F. H. Heinsius, O.P. Gavrichtchouk, M. Chiosso, Martin Bodlak, L. Sinha, François Herrmann, T. Weisrock, T. Matsuda, A. Zink, Takahiro Iwata, G.V. Khaustov, Fabrice Gautheron, H. Matsuda, V. Tskhay, Alexandr Selyunin, N.S. Rogacheva, K. Kurek, V. Andrieux, Adam Szabelski, M. Meyer, L. Dhara, C. Braun, B. Marianski, M. Grosse Perdekamp, M.G. Alexeev, A.V. Efremov, B. Badelek, S. Uhl, A. Vauth, F. Kunne, Bakur Parsamyan, W. Eyrich, Nour Makke, J. Giarra, W. C. Chang, S. Grabmüller, Michal Dziewiecki, B. Ketzer, M. Roskot, S. Takekawa, Anne-Laure Martin, F. Pereira, A. Antoshkin, S. Platchkov, P. Zavada, H. Schmieden, J.M. Friedrich, W. Meyer, Maria Liz Crespo, J. Pretz, K. Zaremba, M. Slunecka, V.A. Polyakov, S. Huber, V. Jary, V.F. Konstantinov, M. Gorzellik, S. Wallner, S. Ishimoto, Kamil Augsten, E. Zemlyanichkina, H. Fischer, M. Aghasyan, G. Sbrizzai, Johannes Bernhard, Ch. Dreisbach, P. Bordalo, A. Guskov, A. Amoroso, J. Pochodzalla, Yakov Petrovich Kulinich, Andrea Bressan, A. Nagaytsev, N. du Fresne von Hohenesche, F. Balestra, N. I. Zhuravlev, N. Pierre, M. Finger, F. Haas, N. C. R. Makins, K. Bicker, E. Fuchey, R. Birsa, J. Lichtenstadt, C. Riedl, Jan Matousek, M. Quaresma, D. Neyret, Nikolay Anfimov, R. Joosten, S. Dasgupta, J. Vondra, A. Austregesilo, Y.-S. Lian, J.F.C.A. Veloso, K. Kondo, Y. Bedfer, O.M. Kouznetsov, A. Srnka, C. Chatterjee, Z.V. Kroumchtein, V. Duic, W. Augustyniak, S. Ramos, K. Schmidt, P. Sznajder, Andrea Ferrero, Norihiro Doshita, N. d'Hose, D. Steffen, J. Smolik, O. Subrt, A. Lehmann, A. Thiel, Q. Curiel, K. Klimaszewski, Y. Miyachi, A.A. Lednev, Andres Cicuttin, I. Orlov, V.D. Samoylenko, G. Reicherz, S. Dalla Torre, Frank Klein, I. Konorov, A. Sandacz, C. Franco, Jen-Chieh Peng, Markus Ball, Yu. Ivanshin, F. Nerling, G. Hamar, M. Büchele, Mikhail Mikhasenko, M. Faessler, J.H. Koivuniemi, B. Grube, R.P. Kurjata, M. Virius, P. Jörg, S. Levorato, N. Mitrofanov, S. Sarkar, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), COMPASS, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Adolph, C., Aghasyan, M., Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., BadeÅ‚ek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Braun, C., Bressan, A., Bã¼chele, M., Chang, W. -. C., Chatterjee, C., Chiosso, M., Choi, I., Chung, S. -. U., Cicuttin, A., Crespo, M. L., Curiel, Q., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, O. Y. u., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, C. h., Duic, V., Quintans, C., Dziewiecki, M., Efremov, A., Eversheim, P. D., Eyrich, W., Ramos, S., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, F., Gnesi, I., Gorzellik, M., Grabmã¼ller, S., Grasso, A., Grosse Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Haas, F., Hahne, D., Hamar, G., von Harrach, D., Heinsius, F. H., Heitz, R., Herrmann, F., Horikawa, N., D'Hose, N., Hsieh, C. -. Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Y. u., Iwata, T., Jary, V., Joosten, R., Jã¶rg, P., Kabuãÿ, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Y. u. A., Kisselev, Y. u., Klein, F., Klimaszewski, K., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Kã¶nigsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Krã¤mer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Lednev, A. A., Lehmann, A., Levillain, M., Levorato, S., Lian, Y. -. S., Lichtenstadt, J., Longo, R., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Marianski, B., Martin, A., Marzec, J., Matouå¡ek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Y. u. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Nagaytsev, A., Nerling, F., Neyret, D., Novã½, J., Nowak, W. -. D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -. C., Pereira, F., Peå¡ek, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Ziembicki, M., Zink, A., Regali, C., Reicherz, G., Riedl, C., Roskot, M., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmidt, K., Schmieden, H., Schã¶nning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Takekawa, S., Tasevsky, M., Tessaro, S., Tessarotto, F., Thibaud, F., Thiel, A., Tosello, F., Tskhay, V., Uhl, S., Vauth, A., Veloso, J., Virius, M., Vondra, J., Wallner, S., Weisrock, T., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., and Zhuravlev, N.

Subjects
hadron: angular distribution, muon+: polarized beam, Nuclear Theory, Parton, muon+ deuteron: deep inelastic scattering, hadron: transverse momentum, transverse momentum dependence, 01 natural sciences, COMPASS, High Energy Physics - Experiment, Subatomär fysik, Sivers function, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), photon gluon: fusion, Subatomic Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], parton, Nuclear Experiment, media_common, Quantum chromodynamics, Physics, gluon: distribution function, deep inelastic scattering: semi-inclusive reaction, higher-order: 0, polarized target: transverse, hep-ph, Deep inelastic scattering, Gluon, PDF, Sivers, TMD, Nuclear and High Energy Physics, lcsh:QC1-999, High Energy Physics - Phenomenology, Siver, effect: Collins, Nucleon, Compton scattering, numerical calculations: Monte Carlo, spin: asymmetry, Particle Physics - Experiment, Quark, Particle physics, data analysis method, deuteron: polarized target, hadron: asymmetry, angular distribution: asymmetry, neural network, media_common.quotation_subject, polarization: longitudinal, FOS: Physical sciences, Asymmetry, Nuclear physics, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], 0103 physical sciences, quantum chromodynamics, 010306 general physics, Particle Physics - Phenomenology, 010308 nuclear & particles physics, hep-ex, 160 GeV/c, High Energy Physics::Phenomenology, nucleon: spin: transverse, CERN SPS, muon+ p: deep inelastic scattering, correlation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, absorption, lcsh:Physics, Lepton, experimental results
Abstract

The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. It was extracted from measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it turned out to be non-zero for quarks. In this letter the evaluation of the Sivers asymmetry for gluons in the same process is presented. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/$c$ muon beam scattered off transversely polarised deuterons and protons. With a significance of more than two standard deviations a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero., Comment: 18 pages, 8 figures

Published
2017

11. Multiplicities of charged pions and charged hadrons from deep-inelastic scattering of muons off an isoscalar target

Author

A. Maggiora, J. Lichtenstadt, S.-U. Chung, N.S. Rossiyskaya, F. Giordano, K. Schmidt, Norihiro Doshita, M. Gorzellik, M. Wilfert, V.I. Nikolaenko, M. Grosse Perdekamp, F. Thibaud, N. d'Hose, V. Anosov, H. Schmieden, J.M. Friedrich, Y.-S. Lian, François Herrmann, C. Adolph, Laura Silva, M. Meyer, A. Grasso, J. Bisplinghoff, M. V. Zavertyaev, M. Roskot, M. Krämer, J. Barth, J. Smolik, W. Augustyniak, S. Ramos, R. Akhunzyanov, S. Huber, E. M. Kabuß, C. Regali, C. Marchand, Y. u. Ivanshin, Gerhard K. Mallot, S. Takekawa, P.D. Eversheim, I. Konorov, H. Suzuki, C.D.R. Azevedo, M. Stolarski, E. Zemlyanichkina, Yakov Petrovich Kulinich, S. Grabmüller, D.V. Peshekhonov, G. D. Alexeev, N. C. R. Makins, P. Zavada, W. Meyer, Maria Liz Crespo, V. Jary, J. Pretz, T. Weisrock, A.V. Efremov, S. Platchkov, M. Tasevsky, F. Pereira, E. Mitrofanov, C. Quintans, Z.V. Kroumchtein, N. du Fresne von Hohenesche, G.V. Meshcheryakov, P. Sznajder, Kamil Augsten, Yu. V. Mikhailov, S. Sirtl, I.A. Savin, W. Dünnweber, V. Andrieux, L. Dhara, M. Faessler, C. Braun, K. Bicker, Adam Szabelski, Mikhail Mikhasenko, D. Steffen, M. Aghasyan, E. Fuchey, Aram Kotzinian, R. Windmolders, Nikolay Anfimov, B. Marianski, B. Badelek, K. Zaremba, F. Tessarotto, Miroslav Sulc, F. Hinterberger, V.A. Polyakov, F. Nerling, R. Jahn, J. Pochodzalla, Andrew Ivanov, A. Magnon, B. Ketzer, G. Sbrizzai, A. Nagaytsev, F. Balestra, N. Pierre, Bakur Parsamyan, O.P. Gavrichtchouk, M. Finger, P. Bordalo, Jan Matousek, M. Ziembicki, Martin Bodlak, A. Rychter, Johannes Bernhard, A. Guskov, P. Montuenga, P. Kremser, R. Longo, F. Haas, L. Sinha, T. Matsuda, A. Zink, V.N. Kolosov, K. Schönning, A. Amoroso, A. Lehmann, R. Joosten, D.I. Ryabchikov, Y. Miyachi, A.A. Lednev, F. H. Heinsius, D. von Harrach, K. Königsmann, M. Slunecka, C. Riedl, Arseniy Rybnikov, B. Grube, T. Michigami, R. Heitz, J. ter Wolbeek, I. Gnesi, Yu. Kisselev, R. Birsa, G.V. Khaustov, Andrea Bressan, L. Capozza, C. Franco, K. Kondo, Franco Bradamante, W.-D. Nowak, N. I. Zhuravlev, Federica Sozzi, A. Sandacz, S. Gerassimov, N. Horikawa, K. Klimaszewski, Frank Klein, V.F. Konstantinov, Y. Bedfer, Jen-Chieh Peng, S. Schopferer, F. Tosello, E. Seder, S. Tessaro, D. Hahne, Fabrice Gautheron, M.G. Alexeev, Chandradoy Chatterjee, S. Ishimoto, H. Fischer, A.G. Olshevsky, M. Levillain, C.-Y. Hsieh, Celso Augusto Guimarães Santos, V. Frolov, S. Uhl, Yu.A. Khokhlov, T. Szameitat, Andres Cicuttin, Q. Curiel, P. Schiavon, Soumen Paul, D. Neyret, T. Sawada, I. Orlov, V.D. Samoylenko, Alexandr Selyunin, G. Reicherz, Michal Dziewiecki, P. Jörg, R. Kuhn, V. Tskhay, W. Eyrich, I. J. Choi, Nour Makke, O.Yu. Shevchenko, S. Levorato, H. Matsuda, Andrea Ferrero, W. C. Chang, Shuddha Shankar Dasgupta, S. Dalla Torre, M. Chiosso, M. Büchele, Alan D. Martin, S. Sarkar, J.H. Koivuniemi, S. Dasgupta, N. Mitrofanov, R.P. Kurjata, A. Austregesilo, F. Krinner, M. Quaresma, O.Yu. Denisov, M. Virius, F. Kunne, G. Nukazuka, K. Kurek, S. V. Donskov, M. Pešek, R. Hashimoto, A.S. Nunes, Takahiro Iwata, R. Beck, D. Panzieri, Janusz Marzec, T. Grussenmeyer, J. Vondra, J.F.C.A. Veloso, O.M. Kouznetsov, A. Srnka, R. Salac, M. Ostrick, E.R. Bielert, V. Duic, M. Boer, J. Nový, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Département de Physique Nucléaire (ex SPhN) ( DPHN ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Adolph, C., Aghasyan, M., Akhunzyanov, R., Alexeev, G. D., Alexeev, M. G., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badełek, B., Balestra, F., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, Renato, Bisplinghoff, J., Bodlak, M., Boer, M., Bordalo, P., Bradamante, Franco, Braun, C., Bressan, Andrea, Büchele, M., Capozza, L., Chang, W. C., Chatterjee, Chandradoy, Chiosso, M., Choi, I., Chung, S. U., Cicuttin, A., Crespo, M. L., Curiel, Q., Dalla Torre, S., Dasgupta, SHUDDHA SHANKAR, Dasgupta, S., Denisov, O. Yu, Dhara, L., Donskov, S. V., Doshita, N., Duic, Venicio, Dünnweber, W., Dziewiecki, M., Efremov, A., Eversheim, P. D., Eyrich, W., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giordano, F., Gnesi, I., Gorzellik, M., Grabmüller, S., Grasso, A., Grosse Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Haas, F., Hahne, D., von Harrach, D., Hashimoto, R., Heinsius, F. H., Heitz, R., Herrmann, F., Hinterberger, F., Horikawa, N., D'Hose, N., Hsieh, C. Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Y. u., Iwata, T., Jahn, R., Jary, V., Joosten, R., Jörg, P., Kabuß, E., Ketzer, B., Khaustov, G. V., Khokhlov, Y. u. A., Kisselev, Y. u., Klein, F., Klimaszewski, K., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Königsmann, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Krämer, M., Kremser, P., Krinner, F., Kroumchtein, Z. V., Kuhn, R., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Lednev, A. A., Lehmann, A., Levillain, M., Levorato, Stefano, Lian, Y. S., Lichtenstadt, J., Longo, R., Maggiora, A., Magnon, A., Makins, N., Makke, Nour, Mallot, G. K., Marchand, C., Marianski, B., Martin, Anna, Marzec, J., Matousek, Jan, Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Michigami, T., Mikhailov, Y. u. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Montuenga, P., Nagaytsev, A., Nerling, F., Neyret, D., Nikolaenko, V. I., Nový, J., Nowak, W. D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. C., Pereira, F., Pešek, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Roskot, M., Rossiyskaya, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, Giulio, Schiavon, Paolo, Schmidt, K., Schmieden, H., Schönning, K., Schopferer, S., Seder, E., Selyunin, A., Shevchenko, O. Yu, Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Sozzi, Federica, Srnka, A., Steffen, D., Stolarski, M., Sulc, M., Suzuki, H., Szabelski, Adam, Szameitat, T., Sznajder, P., Takekawa, Stefano, Tasevsky, M., Tessaro, Susanna, Tessarotto, F., Thibaud, F., Tosello, F., Tskhay, V., Uhl, S., Veloso, J., Virius, M., Vondra, J., Weisrock, T., Wilfert, M., Windmolders, R., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., Ziembicki, M., and Zink, A.

Subjects
Quark, Nuclear and High Energy Physics, Photon, Isoscalar, Hadron, Nuclear Theory, HERMES, target: isoscalar, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 01 natural sciences, COMPASS, scaling: Bjorken, Nuclear physics, Pion, Astronomi, astrofysik och kosmologi, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Astronomy, Astrophysics and Cosmology, Pion multiplicities, Nuclear Physics - Experiment, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], quantum chromodynamics: perturbation theory, 010306 general physics, Nuclear Experiment, RICH, Deep inelastic scattering, Fragmentation functions, Physics, quark: fragmentation function, Muon, pi: multiplicity, hep-ex, 010308 nuclear & particles physics, Scattering, muon: beam, higher-order: 0, Fragmentation function, photon, hadron: energy, lcsh:QC1-999, kinematics, Pion multiplicitie, High Energy Physics::Experiment, Particle Physics - Experiment, lcsh:Physics
Abstract

Multiplicities of charged pions and charged hadrons produced in deep-inelastic scattering were measured in three-dimensional bins of the Bjorken scaling variable x , the relative virtual-photon energy y and the relative hadron energy z . Data were obtained by the COMPASS Collaboration using a 160GeV muon beam and an isoscalar target ( 6 LiD). They cover the kinematic domain in the photon virtuality Q2>1(GeV/c)2 , 0.004 1(GeV/c$)^2$, $0.004 < x < 0.4$, $0.2 < z < 0.85$ and $0.1 < y < 0.7$. In addition, a leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions.

Published
2017

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