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22 results on '"Mikhailov YV"'

1. Exotic meson pi(1) (1600) with J(PC)=1(-+) and its decay into rho(770)pi

Author

Alexeev, GD, Alexeev, MG, Amoroso, A, Andrieux, V, Anosov, V, Augsten, K, Augustyniak, W, Azevedo, CDR, Badelek, B, Balestra, F, Ball, M, Barth, J, Beck, R, Bedfer, Y, Antequera, JB, Bernhard, J, Bodlak, M, Bradamante, F, Bressan, A, Burtsev, VE, Chang, WC, Chatterjee, C, Chiosso, M, Chumakov, AG, Chung, SU, Cicuttin, A, Correia, PMM, Crespo, ML, D'Ago, D, Dalla Torre, S, Dasgupta, SS, Dasgupta, S, Denisenko, I, Denisov, OY, Donskov, SV, Doshita, N, Dreisbach, C, Dunnweber, W, Dusaev, RR, Efremov, A, Eremeev, D, Eversheim, PD, Faccioli, P, Faessler, M, Finger, M, Fischer, H, Floethner, K, Franco, C, Friedrich, JM, Frolov, V, Ordonez, LG, Gautheron, F, Gavrichtchouk, OP, Gerassimov, S, Giarra, J, Giordano, D, Gorzellik, M, Grasso, A, Gridin, A, Perdekamp, MG, Grube, B, Gruner, M, Guskov, A, Haas, F, von Harrach, D, Heitz, R, Hoffmann, M, Horikawa, N, D'Hose, N, Hsieh, CY, Huber, S, Ishimoto, S, Ivanov, A, Iwata, T, Jandek, M, Jary, V, Joosten, R, Kabuss, E, Kaspar, F, Kerbizi, A, Ketzer, B, Khaustov, GV, Khokhlov, YA, Kisselev, Y, Klein, F, Koivuniemi, JH, Kolosov, VN, Konorov, I, Konstantinov, VF, Kotzinian, AM, Kouznetsov, OM, Koval, A, Kral, Z, Krinner, F, Kunne, F, Kurek, K, Kurjata, RP, Kveton, A, Lavickova, K, Levorato, S, Lian, YS, Lichtenstadt, J, Lin, PJ, Longo, R, Lyubovitskij, VE, Maggiora, A, Magnon, A, Makins, N, Makke, N, Mallot, GK, Maltsev, A, Mamon, SA, Marianski, B, Martin, A, Marzec, J, Matousek, J, Matsuda, T, Mattson, G, Metzger, F, Meyer, M, Meyer, W, Mikhailov, YV, Mikhasenko, M, Mitrofanov, E, Miyachi, Y, Moretti, A, Nagaytsev, A, Naim, C, Neyret, D, Novy, J, Nowak, WD, Nukazuka, G, Olshevsky, AG, Ostrick, M, Panzieri, D, Parsamyan, B, Paul, S, Pekeler, H, Peng, JC, Pesek, M, Peshekhonov, DV, Peskova, M, Pierre, N, Platchkov, S, Pochodzalla, J, Polyakov, VA, Pretz, J, Quaresma, M, Quintans, C, Reicherz, G, Riedl, C, Rudnicki, T, Ryabchikov, DI, Rychter, A, Rymbekova, A, Samoylenko, VD, Sandacz, A, Sarkar, S, Savin, IA, Sbrizzai, G, Schmeing, S, Schmieden, H, Selyunin, A, Sharko, K, Sinha, L, Slunecka, M, Spulbeck, D, Srnka, A, Steffen, D, Stolarski, M, Subrt, O, Sulc, M, Suzuki, H, Tessaro, S, Tessarotto, F, Thiel, A, Tomsa, J, Tosello, F, Townsend, A, Triloki, T, Tskhay, V, Uhl, S, Valinoti, B, Vauth, A, Veit, BM, Veloso, J, Ventura, B, Vidon, A, Virius, M, Wagner, M, Wallner, S, Zaremba, K, Zavertyaev, M, Zemko, M, Zemlyanichkina, E, Zhao, Y, Ziembicki, M, Alexeev, Gd, Alexeev, Mg, Amoroso, A, Andrieux, V, Anosov, V, Augsten, K, Augustyniak, W, Azevedo, Cdr, Badelek, B, Balestra, F, Ball, M, Barth, J, Beck, R, Bedfer, Y, Antequera, Jb, Bernhard, J, Bodlak, M, Bradamante, F, Bressan, A, Burtsev, Ve, Chang, Wc, Chatterjee, C, Chiosso, M, Chumakov, Ag, Chung, Su, Cicuttin, A, Correia, Pmm, Crespo, Ml, D'Ago, D, Dalla Torre, S, Dasgupta, S, Denisenko, I, Denisov, Oy, Donskov, Sv, Doshita, N, Dreisbach, C, Dunnweber, W, Dusaev, Rr, Efremov, A, Eremeev, D, Eversheim, Pd, Faccioli, P, Faessler, M, Finger, M, Fischer, H, Floethner, K, Franco, C, Friedrich, Jm, Frolov, V, Ordonez, Lg, Gautheron, F, Gavrichtchouk, Op, Gerassimov, S, Giarra, J, Giordano, D, Gorzellik, M, Grasso, A, Gridin, A, Perdekamp, Mg, Grube, B, Gruner, M, Guskov, A, Haas, F, von Harrach, D, Heitz, R, Hoffmann, M, Horikawa, N, D'Hose, N, Hsieh, Cy, Huber, S, Ishimoto, S, Ivanov, A, Iwata, T, Jandek, M, Jary, V, Joosten, R, Kabuss, E, Kaspar, F, Kerbizi, A, Ketzer, B, Khaustov, Gv, Khokhlov, Ya, Kisselev, Y, Klein, F, Koivuniemi, Jh, Kolosov, Vn, Konorov, I, Konstantinov, Vf, Kotzinian, Am, Kouznetsov, Om, Koval, A, Kral, Z, Krinner, F, Kunne, F, Kurek, K, Kurjata, Rp, Kveton, A, Lavickova, K, Levorato, S, Lian, Y, Lichtenstadt, J, Lin, Pj, Longo, R, Lyubovitskij, Ve, Maggiora, A, Magnon, A, Makins, N, Makke, N, Mallot, Gk, Maltsev, A, Mamon, Sa, Marianski, B, Martin, A, Marzec, J, Matousek, J, Matsuda, T, Mattson, G, Metzger, F, Meyer, M, Meyer, W, Mikhailov, Yv, Mikhasenko, M, Mitrofanov, E, Miyachi, Y, Moretti, A, Nagaytsev, A, Naim, C, Neyret, D, Novy, J, Nowak, Wd, Nukazuka, G, Olshevsky, Ag, Ostrick, M, Panzieri, D, Parsamyan, B, Paul, S, Pekeler, H, Peng, Jc, Pesek, M, Peshekhonov, Dv, Peskova, M, Pierre, N, Platchkov, S, Pochodzalla, J, Polyakov, Va, Pretz, J, Quaresma, M, Quintans, C, Reicherz, G, Riedl, C, Rudnicki, T, Ryabchikov, Di, Rychter, A, Rymbekova, A, Samoylenko, Vd, Sandacz, A, Sarkar, S, Savin, Ia, Sbrizzai, G, Schmeing, S, Schmieden, H, Selyunin, A, Sharko, K, Sinha, L, Slunecka, M, Spulbeck, D, Srnka, A, Steffen, D, Stolarski, M, Subrt, O, Sulc, M, Suzuki, H, Tessaro, S, Tessarotto, F, Thiel, A, Tomsa, J, Tosello, F, Townsend, A, Triloki, T, Tskhay, V, Uhl, S, Valinoti, B, Vauth, A, Veit, Bm, Veloso, J, Ventura, B, Vidon, A, Virius, M, Wagner, M, Wallner, S, Zaremba, K, Zavertyaev, M, Zemko, M, Zemlyanichkina, E, Zhao, Y, and Ziembicki, M

Subjects
PWQ, Structure, pions
Abstract

We study the spin-exotic J(PC)=1(-+) amplitude in single-diffractive dissociation of 190 GeV/c pions into pi(-)pi(-)pi(+) using a hydrogen target and confirm the pi(1)(1600) -> rho(770)pi amplitude, which interferes with a nonresonant 1(-+) amplitude. We demonstrate that conflicting conclusions from previous studies on these amplitudes can be attributed to different analysis models and different treatment of the dependence of the amplitudes on the squared four-momentum transfer and we thus reconcile these experimental findings. We study the nonresonant contributions to the pi(-)pi(-)pi(+) final state using pseudodata generated on the basis of a Deck model. Subjecting pseudodata and real data to the same partial-wave analysis, we find good agreement concerning the spectral shape and its dependence on the squared four-momentum transfer for the J(PC)=1(-+) amplitude and also for amplitudes with other J(PC) quantum numbers. We investigate for the first time the amplitude of the pi(-)pi(+) subsystem with J(PC)=1(--) in the 3 pi amplitude with J(PC)=1(-+) employing the novel freed-isobar analysis scheme. We reveal this pi(-)pi(+) amplitude to be dominated by the rho(770) for both the pi(1)(1600) and the nonresonant contribution. These findings largely confirm the underlying assumptions for the isobar model used in all previous partial-wave analyses addressing the J(PC)=1(-+) amplitude.

Published
2022

2. Odd and even partial waves of eta pi(-) and eta 'pi(-) in pi(-) p -> eta((')) pi(-) p at 191 GeV/c (vol 740, pg 303, 2015)

Author

Adolph, C, Akhunzyanov, R, Alexeev, Mg, Alexeev, Gd, Amoroso, A, Andrieux, V, Anosov, V, Austregesilo, A, Badelek, B, Balestra, F, Barth, J, Baum, G, Beck, R, Bedfer, Y, Berlin, A, Bernhard, J, Bicker, K, Bielert, Er, Bieling, J, Birsa, R, Bisplinghoff, J, Bodlak, M, Boer, M, Bordalo, P, Bradamante, F, Braun, C, Bressan, A, Buchele, M, Burtin, E, Capozza, L, Chiosso, M, Chung, Su, Cicuttin, A, Crespo, Ml, Curiel, Q, Dalla Torre, S, Dasgupta, Ss, Dasgupta, S, Denisov, Oy, Donskov, Sv, Doshita, N, Duic, V, Dunnweber, W, Dziewiecki, M, Efremov, A, Elia, C, Eversheim, Pd, Eyrich, W, Faessler, M, Ferrero, A, Finger, M, Fischer, H, Franco, C, von Hohenesche, Nd, Friedrich, Jm, Frolov, V, Gautheron, F, Gavrichtchouk, Op, Gerassimov, S, Geyer, R, Gnesi, I, Gobbo, B, Goertz, S, Gorzellik, M, Grabmuller, S, Grasso, A, Grube, B, Grussenmeyer, T, Guskov, A, Haas, F, von Harrach, D, Hahne, D, Hashimoto, R, Heinsius, Fh, Herrmann, F, Hinterberger, F, Hoppner, C, Horikawa, N, D'Hose, N, Huber, S, Ishimoto, S, Ivanov, A, Ivanshin, Y, Iwata, T, Jahn, R, Jary, V, Jasinski, P, Jorg, P, Joosten, R, Kabuss, E, Ketzer, B, Khaustov, Gv, Khokhlov, Ya, Kisselev, Y, Klein, F, Klimaszewski, K, Koivuniemi, Jh, Kolosov, Vn, Kondo, K, Konigsmann, K, Konorov, I, Konstantinov, Vf, Kotzinian, Am, Kouznetsov, O, Kramer, M, Kroumchtein, Zv, Kuchinski, N, Kunne, F, Kurek, K, Kurjata, Rp, Lednev, Aa, Lehmann, A, Levillain, M, Levorato, S, Lichtenstadt, J, Maggiora, A, Magnon, A, Makke, N, Mallot, Gk, Marchand, C, Martin, A, Marzec, J, Matousek, J, Matsuda, H, Matsuda, T, Meshcheryakov, G, Meyer, W, Michigami, T, Mikhailov, Yv, Mikhasenko, M, Miyachi, Y, Nagaytsev, A, Nagel, T, Nerling, F, Neubert, S, Neyret, D, Novy, J, Nowak, Wd, Nunes, As, Olshevsky, Ag, Orlov, I, Ostrick, M, Panknin, R, Panzieri, D, Parsamyan, B, Paul, S, Peshekhonov, Dv, Platchkov, S, Pochodzalla, J, Polyakov, Va, Pretz, J, Quaresma, M, Quintans, C, Ramos, S, Regali, C, Reicherz, G, Rocco, E, Rossiyskaya, Ns, Ryabchikov, Di, Rychter, A, Samoylenko, Vd, Sandacz, A, Sarkar, S, Savin, Ia, Sbrizzai, G, Schiavon, P, Schill, C, Schluter, T, Schmidt, K, Schmieden, H, Schonning, K, Schopferer, S, Schott, M, Shevchenko, Oy, Silva, L, Sinha, L, Sirtl, S, Slunecka, M, Sosio, S, Sozzi, F, Srnka, A, Steiger, L, Stolarski, M, Sulc, M, Sulej, R, Suzuki, H, Szabelski, A, Szameitat, T, Sznajder, P, Takekawa, S, ter Wolbeek, J, Tessaro, S, Tessarotto, F, Thibaud, F, Uhl, S, Uman, I, Virius, M, Wang, L, Weisrock, T, Wilfert, M, Windmolders, R, Wollny, H, Zaremba, K, Zavertyaev, M, Zemlyanichkina, E, Ziembicki, M, and Zink, A

Published
2020

3. Measurement of the longitudinal spin transfer to Lambda and (Lambda)over-bar hyperons in polarised muon DIS

Author

Alexeev, Maxim, Alexakhin, Vy, Alexandrov, Y, Alexeev, Gd, Amoroso, Antonio, Austregesilo, A, Badelek, B, Balestra, Ferruccio, Ball, J, Barth, J, Baum, G, Bedfer, Y, Bernhard, J, Bertini, R, Bettinelli, M, Birsa, R, Bisplinghoff, J, Bordalo, P, Bradamante, F, Bravar, A, Bressan, A, Brona, G, Burtin, E, Bussa, Maria Pia, Chapiro, A, Chiosso, Michela, Chung, Su, Cicuttin, A, Colantoni, M, Crespo, Ml, Dalla Torre, S, Dafni, T, Das, S, Dasgupta, Ss, Denisov, Oy, Dhara, L, Diaz, V, Dinkelbach, Am, Donskov, Sv, Doshita, N, Duic, V, Dunnweber, W, Efremov, A, Eversheim, Pd, Eyrich, W, Faessler, M, Ferrero, A, Finger, M, Fischer, H, Franco, C, Friedrich, Jm, Garfagnini, R, Gautheron, F, Gavrichtchouk, Op, Gazda, R, Gerassimov, S, Geyer, R, Giorgi, M, Gobbo, B, Goertz, S, Grabmuller, S, Grajek, Oa, Grasso, Antonino, Grube, B, Gushterski, R, Guskov, A, Haas, F, von Harrach, D, Hasegawa, T, Heckmann, J, Heinsius, Fh, Hermann, M, Hermann, R, Herrmann, F, Hess, C, Hinterberger, F, Horikawa, N, Hoppner, C, D'Hose, N, Ilgner, C, Ishimoto, S, Ivanov, O, Ivanshin, Y, Iven, B, Iwata, T, Jahn, R, Jasinski, P, Jegou, G, Joosten, R, Kabuss, E, Kang, D, Ketzer, B, Khaustov, Gv, Khokhlov, Ya, Kisselev, Y, Klein, F, Klimaszewski, K, Koblitz, S, Koivuniemi, Jh, Kolosov, Vn, Komissarov, Ev, Kondo, K, Konigsmann, K, Konopka, R, Konorov, I, Konstantinov, Vf, Korzenev, A, Kotzinian, Am, Kouznetsov, O, Kowalik, K, Kramer, M, Kral, A, Kroumchtein, Zv, Kuhn, R, Kunne, F, Kurek, K, Le Goff JM, Lednev, Aa, Lehmann, A, Levorato, S, Lichtenstadt, J, Liska, T, Maggiora, A, Maggiora, Marco, Magnon, A, Mallot, Gk, Mann, A, Marchand, C, Marroncle, J, Martin, A, Marzec, J, Massmann, F, Matsuda, T, Maximov, An, Meyer, W, Michigami, T, Mikhailov, Yv, Moinester, Ma, Mutter, A, Nagaytsev, A, Nagel, T, Nassalski, J, Negrini, S, Nerling, F, Neubert, S, Neyret, D, Nikolaenko, Vi, Olshevsky, Ag, Ostrick, M, Padee, A, Panknin, R, Panzieri, D, Parsamyan, Bakur, Paul, S, Pawlukiewicz Kaminska, B, Perevalova, E, Pesaro, G, Peshekhonov, Dv, Piragino, Guido, Platchkov, S, Pochodzalla, J, Polak, J, Polyakov, Va, Pontecorvo, G, Pretz, J, Quintans, C, Rajotte, Jf, Ramos, S, Rapatsky, V, Reicherz, G, Reggiani, D, Richter, A, Robinet, F, Rocco, Elena, Rondio, E, Ryabchikov, Di, Samoylenko, Vd, Sandacz, A, Santos, H, Sapozhnikov, Mg, Sarkar, S, Sbrizzai, G, Schiavon, P, Schill, C, Schmitt, L, Schroder, W, Shevchenko, Oy, Siebert, Hw, Silva, L, Sinha, L, Sissakian, An, Slunecka, M, Smirnov, Gi, Sosio, Stefano, Sozzi, F, Srnka, A, Stolarski, M, Sulc, M, Sulej, R, Takekawa, S, Tessaro, S, Tessarotto, F, Teufel, A, Tkatchev, Lg, Venugopal, G, Virius, M, Vlassov, Nv, Vossen, A, Weitzel, Q, Windmolders, R, Wislicki, W, Wollny, H, Zaremba, K, Zemlyanichkina, E, Ziembicki, M, Zhao, J, Zhuravlev, N, and Zvyagin, A.

Subjects
CHARGED-CURRENT INTERACTIONS, DEEP, NOMAD EXPERIMENT, ASYMMETRY, SCATTERING, STRANGE PARTICLE-PRODUCTION, NUCLEON, FRAGMENTATION, NEUTRINO, DECAYS
Published
2009

4. An efficient high-voltage power supply for a photomultiplier tube

Author

Ainutdinov, VM, Vonsovskii, NN, Kompaniets, KG, Kozyr, AI, Mikhailov, YV, and University of Groningen

Abstract

An adjustable power supply for a photomultiplier tube operating in the pulsed spectrometric mode with a wide range of linearity is described. The power consumed by the source is 50 mW. The output voltage is varied from 800 to 2000 V. The maximum ripple amplitude is 2.5 mV.

Published
2003

5. Probing transversity by measuring Λ polarisation in SIDIS

Author

Compass Collaboration, Alexeev, G. D., Balestra, F., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Lavickova, K., Levorato, S., Lian, Y.-S., Lichtenstadt, J., Lin, P.-J., Longo, R., Ball, M., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Maltsev, A., Mamon, S. A., Marianski, B., Martin, A., Barth, J., Marzec, J., Matoušek, J., Matsuda, T., Mattson, G., Meshcheryakov, G. V., Metzger, F., Meyer, M., Meyer, W., Mikhailov, Yu V., Mikhasenko, M., Beck, R., Mitrofanov, E., Miyachi, Y., Moretti, A., Nagaytsev, A., Naim, C., Negrini, T. S., Neyret, D., Nový, J., Nowak, W.-D., Nukazuka, G., Bedfer, Y., Nunes, A. S., Olshevsky, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Pekeler, H., Peng, J.-C., Rudnicki, T., Pešek, M., Berenguer Antequera, J., Peshekhonov, D. V., Pešková, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, Jörg, Quaresma, M., Quintans, C., Reicherz, G., Bernhard, J., Riedl, C., Ryabchikov, D. I., Rychter, A., Rymbekova, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schiavon, P., Bodlak, M., Schmieden, H., Selyunin, A., Sharko, K., Sinha, L., Slunecka, M., Smolik, J., Sozzi, F., Srnka, A., Steffen, D., Stolarski, M., Bradamante, F., Subrt, O., Sulc, M., Suzuki, H., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Townsend, A., Bressan, A., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Ventura, B., Vidon, A., Virius, M., Wagner, M., Alexeev, M. G., Burtsev, V. E., Wallner, S., Zaremba, K., Zavada, P., Zavertyaev, M., Zemko, M., Zemlyanichkina, E., Zhao, Y., Ziembicki, M., 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., Amoroso, A., 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., Andrieux, V., Efremov, A., Elia, C., Eremeev, D., Eversheim, P. D., Faccioli, P., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Anosov, V., Flöthner, K. J., Franco, C., Friedrich, J. M., Frolov, V., Garcia Ordòñez, L. G., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Giordano, D., Augsten, K., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Guskov, A., von Harrach, D., Heitz, R., Hoffmann, M., Augustyniak, W., Horikawa, N., d'Hose, N., Hsieh, C.-Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jandek, M., Jary, V., Joosten, R., Azevedo, C. D. R., Kabuß, E., Kang, D.-H., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Badełek, B., 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., Alexeev, Gd, Alexeev, Mg, Amoroso, A, Andrieux, V, Anosov, V, Augsten, K, Augustyniak, W, Azevedo, Cdr, Badelek, B, Balestra, F, Ball, M, Barth, J, Beck, R, Bedfer, Y, Antequera, Jb, Bernhard, J, Bodlak, M, Bradamante, F, Bressan, A, Burtsev, Ve, Chang, Wc, Chatterjee, C, Chiosso, M, Chumakov, Ag, Chung, Su, Cicuttin, A, Correia, Pmm, Crespo, Ml, D'Ago, D, Dalla Torre, S, Dasgupta, S, Denisenko, I, Denisov, Oy, Donskov, Sv, Doshita, N, Dreisbach, C, Dunnweber, W, Dusaev, Rr, Efremov, A, Elia, C, Eremeev, D, Eversheim, Pd, Faccioli, P, Faessler, M, Ferrero, A, Finger, M, Fischer, H, Flothner, Kj, Franco, C, Friedrich, Jm, Frolov, V, Ordonez, Lgg, Gautheron, F, Gavrichtchouk, Op, Gerassimov, S, Giarra, J, Giordano, D, Gnesi, I, Gorzellik, M, Grasso, A, Gridin, A, Perdekamp, Mg, Grube, B, Guskov, A, von Harrach, D, Heitz, R, Hoffmann, M, Horikawa, N, D'Hose, N, Hsieh, Cy, Huber, S, Ishimoto, S, Ivanov, A, Iwata, T, Jandek, M, Jary, V, Joosten, R, Kabuss, E, Kang, Dh, Kaspar, F, Kerbizi, A, Ketzer, B, Khaustov, Gv, Khokhlov, Ya, Kisselev, Y, Klein, F, Koivuniemi, Jh, Kolosovs, 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, Lichtenstadt, J, Lin, N, Longo, R, Lyubovitskij, Ve, Maggiora, A, Magnon, A, Makins, N, Makke, N, Mallot, Gk, Maltsev, A, Mamon, Sa, Marianski, B, Martin, A, Marzec, J, Matousek, J, Matsuda, T, Mattson, G, Meshcheryakov, Gv, Metzger, F, Meyer, M, Meyer, W, Mikhailov, Yv, Mikhasenko, M, Mitrofanov, E, Miyachi, Y, Moretti, A, Nagaytsev, A, Naim, C, Negrini, T, Neyret, D, Novy, J, Nowak, Wd, Nukazuka, G, Nunes, A, Olshevsky, Ag, Ostrick, M, Panzieri, D, Parsamyan, B, Paul, S, Pekeler, H, Peng, Jc, Pesek, M, Peshekhonov, Dv, Peskova, M, Pierre, N, Platchkov, S, Pochodzalla, J, Polyakov, Va, Pretz, J, Quaresma, M, Quintans, C, Reicherz, G, Riedl, C, Rudnicki, T, Ryabchikov, Di, Rychter, A, Rymbekova, A, Samoylenko, Vd, Sandacz, A, Sarkar, S, Savin, Ia, Sbrizzai, G, Schiavon, R, Schmieden, H, Selyunin, A, Sharko, K, Sinha, L, Slunecka, M, Smolik, J, Sozzi, F, Srnka, A, Steffen, D, Stolarski, M, Subrt, O, Sulc, M, Suzuki, H, Sznajder, R, 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, R, 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, and COMPASS

Subjects
quark: distribution function, Nuclear and High Energy Physics, QC1-999, polarization: longitudinal, Nuclear Theory, mass spectrum: (anti-p pi+), FOS: Physical sciences, muon: secondary beam, 01 natural sciences, COMPASS, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), mass spectrum: (p pi-), 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Quantum chromodynamic, quark: polarization: transverse, ddc:530, 010306 general physics, Nuclear Experiment, hyperon: final state, Antilambda: polarization, deep inelastic scattering: semi-inclusive reaction, 010308 nuclear & particles physics, polarized target: transverse, Physics, High Energy Physics::Phenomenology, Lambda: polarization, nucleon: polarization: transverse, CERN SPS, Lambda polarisation, Transversity, High Energy Physics::Experiment, Quantum chromodynamics, Deep inelastic scattering, muon: polarized beam, spin: asymmetry, Particle Physics - Experiment, experimental results
Abstract

Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions $h_1^q$ are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of $\Lambda$ hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversity-induced polarisation of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on $h_1^u$ and $h_1^d$., Comment: 18 pages, 6 figures

Published
2022

6. High-Statistics Measurement of Collins and Sivers Asymmetries for Transversely Polarized Deuterons.

Author

Alexeev GD, Alexeev MG, Alice C, Amoroso A, Andrieux V, Anosov V, Asatryan S, Augsten K, Augustyniak W, Azevedo CDR, Badelek B, Barth J, Beck R, Beckers J, Bedfer Y, Bernhard J, Bodlak M, Bradamante F, Bressan A, Chang WC, Chatterjee C, Chiosso M, Chumakov AG, Chung SU, Cicuttin A, Correia PMM, Crespo ML, D'Ago D, Dalla Torre S, Dasgupta SS, Dasgupta S, Delcarro F, Denisenko I, Denisov OY, Donskov SV, Doshita N, Dreisbach C, Dünnweber W, Dusaev RR, Ecker D, Eremeev D, Faccioli P, Faessler M, Finger M, Finger M, Fischer H, Flöthner KJ, Florian W, Friedrich JM, Frolov V, Garcia Ordòñez LG, Gautheron F, Gavrichtchouk OP, Gerassimov S, Giarra J, Giordano D, Grasso A, Gridin A, Grosse Perdekamp M, Grube B, Grüner M, Guskov A, Haas P, von Harrach D, Hoffmann M, Hoghmrtsyan A, d'Hose N, Hsieh CY, Huber S, Ishimoto S, Ivanov A, Iwata T, Jary V, Joosten R, Kabuß E, Kaspar F, Kerbizi A, Ketzer B, Khatun A, Khaustov GV, Klasek T, Klein F, Koivuniemi JH, Kolosov VN, Kondo Horikawa K, Konorov I, Konstantinov VF, Korzenev AY, Kotzinian AM, Kouznetsov OM, Koval A, Kral Z, Krinner F, Kunne F, Kurek K, Kurjata RP, Kveton A, Lavickova K, Levorato S, Lian YS, Lichtenstadt J, Lin PJ, Longo R, Lyubovitskij VE, Maggiora A, Magnon A, Makke N, Mallot GK, Maltsev A, Martin A, Marzec J, Matoušek J, Matsuda T, Mattson G, Menezes Pires C, Metzger F, Meyer M, Meyer W, Mikhailov YV, Mikhasenko M, Mitrofanov E, Miura D, Miyachi Y, Molina R, Moretti A, Movsisyan A, Nagaytsev A, Neyret D, Niemiec M, Nový J, Nowak WD, Nukazuka G, Olshevsky AG, Ostrick M, Panzieri D, Parsamyan B, Paul S, Pekeler H, Peng JC, Pešek M, Peshekhonov DV, Pešková M, Platchkov S, Pochodzalla J, Polyakov VA, Quaresma M, Quintans C, Reicherz G, Riedl C, Ryabchikov DI, Rychter A, Rymbekova A, Samoylenko VD, Sandacz A, Sarkar S, Savin IA, Sbrizzai G, Schmieden H, Selyunin A, Sharko K, Sinha L, Spülbeck D, Srnka A, Stolarski M, Sulc M, Suzuki H, Takanashi Y, Tessaro S, Tessarotto F, Thiel A, Tosello F, Townsend A, Triloki T, Tskhay V, Valinoti B, Veit BM, Veloso JFCA, Ventura B, Vijayakumar A, Virius M, Wagner M, Wallner S, Zaremba K, Zavertyaev M, Zemko M, Zemlyanichkina E, and Ziembicki M

Abstract

New results are presented on a high-statistics measurement of Collins and Sivers asymmetries of charged hadrons produced in deep inelastic scattering of muons on a transversely polarized ^{6}LiD target. The data were taken in 2022 with the COMPASS spectrometer using the 160 GeV muon beam at CERN, statistically balancing the existing data on transversely polarized proton targets. The first results from about two-thirds of the new data have total uncertainties smaller by up to a factor of three compared to the previous deuteron measurements. Using all the COMPASS proton and deuteron results, both the transversity and the Sivers distribution functions of the u and d quark, as well as the tensor charge in the measured x range are extracted. In particular, the accuracy of the d quark results is significantly improved.

Published
2024
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7. Final COMPASS Results on the Transverse-Spin-Dependent Azimuthal Asymmetries in the Pion-Induced Drell-Yan Process.

Author

Alexeev GD, Alexeev MG, Alice C, Amoroso A, Andrieux V, Anosov V, Augsten K, Augustyniak W, Azevedo CDR, Badelek B, Barth J, Beck R, Beckers J, Bedfer Y, Bernhard J, Bodlak M, Bradamante F, Bressan A, Chang WC, Chatterjee C, Chiosso M, Chumakov AG, Chung SU, Cicuttin A, Correia PMM, Crespo ML, D'Ago D, Dalla Torre S, Dasgupta SS, Dasgupta S, Delcarro F, Denisenko I, Denisov OY, Donskov SV, Doshita N, Dreisbach C, Dünnweber W, Dusaev RR, Ecker D, Eremeev D, Faccioli P, Faessler M, Finger M, Finger M, Fischer H, Flöthner KJ, Florian W, Friedrich JM, Frolov V, Garcia Ordòñez LG, Gautheron F, Gavrichtchouk OP, Gerassimov S, Giarra J, Giordano D, Grasso A, Gridin A, Grosse Perdekamp M, Grube B, Grüner M, Guskov A, Haas P, von Harrach D, Heitz R, Hoffmann M, d'Hose N, Hsieh CY, Huber S, Ishimoto S, Ivanov A, Iwata T, Jary V, Joosten R, Kabuß E, Kaspar F, Kerbizi A, Ketzer B, Khatun A, Khaustov GV, Klein F, Koivuniemi JH, Kolosov VN, Kondo Horikawa K, Konorov I, Konstantinov VF, Korzenev AY, Kotzinian AM, Kouznetsov OM, Koval A, Kral Z, Krinner F, Kunne F, Kurek K, Kurjata RP, Kveton A, Lavickova K, Levorato S, Lian YS, Lichtenstadt J, Lin PJ, Longo R, Lyubovitskij VE, Maggiora A, Magnon A, Makke N, Mallot GK, Maltsev A, Martin A, Marzec J, Matoušek J, Matsuda T, Mattson G, Menezes Pires C, Metzger F, Meyer M, Meyer W, Mikhailov YV, Mikhasenko M, Mitrofanov E, Miura D, Miyachi Y, Molina R, Moretti A, Nagaytsev A, Neyret D, Niemiec M, Nový J, Nowak WD, Nukazuka G, Olshevsky AG, Ostrick M, Panzieri D, Parsamyan B, Paul S, Pekeler H, Peng JC, Pešek M, Peshekhonov DV, Pešková M, Platchkov S, Pochodzalla J, Polyakov VA, Quaresma M, Quintans C, Reicherz G, Riedl C, Ryabchikov DI, Rychter A, Rymbekova A, Samoylenko VD, Sandacz A, Sarkar S, Savada T, Savin IA, Sbrizzai G, Schmieden H, Selyunin A, Sharko K, Sinha L, Spülbeck D, Srnka A, Stolarski M, Sulc M, Suzuki H, Tessaro S, Tessarotto F, Thiel A, Tosello F, Townsend A, Triloki T, Tskhay V, Valinoti B, Veit BM, Veloso JFCA, Ventura B, Vijayakumar A, Virius M, Wagner M, Wallner S, Zaremba K, Zavertyaev M, Zemko M, Zemlyanichkina E, and Ziembicki M

Abstract

The COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190  GeV/c π^{-} beam impinging on a transversely polarized ammonia target. Combining the data of both years, we present final results on the amplitudes of five azimuthal modulations, which correspond to transverse-spin-dependent azimuthal asymmetries (TSAs) in the dimuon production cross section. Three of them probe the nucleon leading-twist Sivers, transversity, and pretzelosity transverse-momentum dependent (TMD) parton distribution functions (PDFs). The other two are induced by subleading effects. These TSAs provide unique new inputs for the study of the nucleon TMD PDFs and their universality properties. In particular, the Sivers TSA observed in this measurement is consistent with the fundamental QCD prediction of a sign change of naive time-reversal-odd TMD PDFs when comparing the Drell-Yan process with deep inelastic scattering. Also, within the context of model predictions, the observed transversity TSA is consistent with the expectation of a sign change for the Boer-Mulders function.

Published
2024
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8. Search for a New B-L Z^{'} Gauge Boson with the NA64 Experiment at CERN.

Author

Andreev YM, Banerjee D, Banto Oberhauser B, Bernhard J, Bisio P, Burtsev VE, Celentano A, Charitonidis N, Chumakov AG, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Frolov VN, Gardikiotis A, Gerassimov SG, Gninenko SN, Hösgen M, Jeckel M, Kachanov VA, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kolosov VN, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Marsicano L, Matveev VA, Mikhailov YV, Molina Bueno L, Peshekhonov DV, Polyakov VA, Radics B, Rubbia A, Samalantin KM, Samoylenko VD, Sieber H, Shchukin D, Soto O, Tikhomirov VO, Tlisova IV, Toropin AN, Vasilishin BI, Volkov PV, Volkov VY, Voronchikhin I, and Zamora-Saá J

Abstract

A search for a new Z^{'} gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data with 3.22×10^{11} electrons on target collected during 2016-2021 runs, no signal events were found. This allows us to derive new constraints on the Z^{'}-e coupling strength, which, for the mass range 0.3≲m_{Z^{'}}≲100  MeV, are more stringent compared to those obtained from the neutrino-electron scattering data.

Published
2022
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9. Triangle Singularity as the Origin of the a_{1}(1420).

Author

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, Berenguer Antequera J, Bernhard J, Bodlak M, Bradamante F, Bressan A, Burtsev VE, Chang WC, Chatterjee C, Chiosso M, Chumakov AG, Chung SU, Cicuttin A, Correia PMM, Crespo ML, D'Ago D, Dalla Torre S, 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, 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, Grosse Perdekamp M, Grube B, Guskov A, von Harrach D, Heitz R, Herrmann F, Horikawa N, d'Hose N, Hsieh CY, 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 GV, Khokhlov YA, Kisselev Y, Klein F, Koivuniemi JH, Kolosov VN, Kondo Horikawa K, 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 YS, Lichtenstadt J, Lin PJ, 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 WD, Nukazuka G, Nunes AS, Olshevsky AG, Ostrick M, Panzieri D, Parsamyan B, Paul S, Pekeler H, Peng JC, Pešek M, Peshekhonov DV, Pešková M, Pierre N, Platchkov S, Pochodzalla J, Polyakov VA, Pretz J, Quaresma M, Quintans 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, 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, and Ziembicki M

Abstract

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. 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 resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π 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 fewer 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 resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

Published
2021
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10. Constraints on New Physics in Electron g-2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector.

Author

Andreev YM, Banerjee D, Bernhard J, Burtsev VE, Chumakov AG, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Charitonidis N, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Gninenko SN, Hösgen M, Kachanov VA, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kolosov VN, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Molina Bueno L, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Sieber H, Shchukin D, Tikhomirov VO, Tlisova I, Toropin AN, Trifonov AY, Vasilishin BI, Volkov PV, and Volkov VY

Abstract

We performed a search for a new generic X boson, which could be a scalar (S), pseudoscalar (P), vector (V), or an axial vector (A) particle produced in the 100 GeV electron scattering off nuclei, e^{-}Z→e^{-}ZX, followed by its invisible decay in the NA64 experiment at CERN. No evidence for such a process was found in the full NA64 dataset of 2.84×10^{11} electrons on target. We place new bounds on the S, P, V, A coupling strengths to electrons, and set constraints on their contributions to the electron anomalous magnetic moment a_{e}, |Δa_{X}|≲10^{-15}-10^{-13} for the X mass region 1  MeV≲m_{X}≲1  GeV. These results are an order of magnitude more sensitive compared to the current accuracy on a_{e} from the electron g-2 experiments and recent high-precision determination of the fine structure constant.

Published
2021
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11. Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel.

Author

Cazzaniga C, Odagiu P, Depero E, Molina Bueno L, Andreev YM, Banerjee D, Bernhard J, Burtsev VE, Charitonidis N, Chumakov AG, Cooke D, Crivelli P, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Girod S, Gninenko SN, Hösgen M, Kachanov VA, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kolosov VN, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Shchukin D, Sieber H, Tikhomirov VO, Tlisova IV, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin BI, Arenas GV, Volkov PV, Volkov VY, and Ulloa P

Abstract

We report the results of a search for a new vector boson ( A ' ) decaying into two dark matter particles χ 1 χ 2 of different mass. The heavier χ 2 particle subsequently decays to χ 1 and an off-shell Dark Photon A ' ∗ → e + e - . For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained re-analyzing the previous NA64 searches for an invisible decay A ' → χ χ ¯ and axion-like or pseudo-scalar particles a → γ γ . With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for A ' masses from 2 m e up to 390 MeV and mixing parameter ε between 3 × 10 - 5 and 2 × 10 - 2 ., (© The Author(s) 2021.)

Published
2021
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12. Search for Axionlike and Scalar Particles with the NA64 Experiment.

Author

Banerjee D, Bernhard J, Burtsev VE, Chumakov AG, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Charitonidis N, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Gninenko SN, Hösgen M, Jeckel M, Kachanov VA, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kolosov VN, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Molina Bueno L, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Sieber H, Shchukin D, Tikhomirov VO, Tlisova I, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin BI, Vasquez Arenas G, Volkov PV, Volkov VY, and Ulloa P

Abstract

We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by the nuclei of the dump. The a(s) would penetrate the downstream HCAL module, serving as a shield, and would be observed either through their a(s)→γγ decay in the rest of the HCAL detector, or as events with a large missing energy if the a(s) decays downstream of the HCAL. This method allows for the probing of the a(s) parameter space, including those from generic axion models, inaccessible to previous experiments. No evidence of such processes has been found from the analysis of the data corresponding to 2.84×10^{11} electrons on target, allowing us to set new limits on the a(s)γγ-coupling strength for a(s) masses below 55 MeV.

Published
2020
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13. Hunting down the X17 boson at the CERN SPS.

Author

Depero E, Andreev YM, Banerjee D, Bernhard J, Burtsev VE, Charitonidis N, Chumakov AG, Cooke D, Crivelli P, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Girod S, Gninenko SN, Hösgen M, Kachanov VA, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kolosov VN, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Bueno LM, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Shchukin D, Sieber H, Tikhomirov VO, Tlisova V, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin BI, Arenas GV, Volkov PV, Volkov VY, and Ulloa P

Abstract

Recently, the ATOMKI experiment has reported new evidence for the excess of e + e - events with a mass ∼ 17 MeV in the nuclear transitions of 4 He, that they previously observed in measurements with 8 Be. These observations could be explained by the existence of a new vector X 17 boson. So far, the search for the decay X 17 → e + e - with the NA64 experiment at the CERN SPS gave negative results. Here, we present a new technique that could be implemented in NA64 aiming to improve the sensitivity and to cover the remaining X 17 parameter space. If a signal-like event is detected, an unambiguous observation is achieved by reconstructing the invariant mass of the X 17 decay with the proposed method. To reach this goal an optimization of the X 17 production target, as well as an efficient and accurate reconstruction of two close decay tracks, is required. A dedicated analysis of the available experimental data making use of the trackers information is presented. This method provides independent confirmation of the NA64 published results [1], validating the tracking procedure. The detailed Monte Carlo study of the proposed setup and the background estimate show that the goal of the proposed search is feasible., (© The Author(s) 2020.)

Published
2020
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14. Dark Matter Search in Missing Energy Events with NA64.

Author

Banerjee D, Burtsev VE, Chumakov AG, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Charitonidis N, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Gninenko SN, Hösgen M, Jeckel M, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Molina Bueno L, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Shchukin D, Tikhomirov VO, Tlisova I, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin BI, Vasquez Arenas G, Volkov PV, Volkov VY, and Ulloa P

Abstract

A search for sub-GeV dark matter production mediated by a new vector boson A^{'}, called a dark photon, is performed by the NA64 experiment in missing energy events from 100 GeV electron interactions in an active beam dump at the CERN SPS. From the analysis of the data collected in the years 2016, 2017, and 2018 with 2.84×10^{11} electrons on target no evidence of such a process has been found. The most stringent constraints on the A^{'} mixing strength with photons and the parameter space for the scalar and fermionic dark matter in the mass range ≲0.2  GeV are derived, thus demonstrating the power of the active beam dump approach for the dark matter search.

Published
2019
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15. Search for a Hypothetical 16.7 MeV Gauge Boson and Dark Photons in the NA64 Experiment at CERN.

Author

Banerjee D, Burtsev VE, Chumakov AG, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dusaev RR, Enik T, Charitonidis N, Feshchenko A, Frolov VN, Gardikiotis A, Gerassimov SG, Gninenko SN, Hösgen M, Jeckel M, Karneyeu AE, Kekelidze G, Ketzer B, Kirpichnikov DV, Kirsanov MM, Konorov IV, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Peshekhonov DV, Polyakov VA, Radics B, Rojas R, Rubbia A, Samoylenko VD, Tikhomirov VO, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin BI, Vasquez Arenas G, Volkov PV, Volkov V, and Ulloa P

Abstract

We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of e^{+}e^{-} pairs observed in the excited ^{8}Be^{*} nucleus decays. Because of its coupling to electrons, the X could be produced in the bremsstrahlung reaction e^{-}Z→e^{-}ZX by a 100 GeV e^{-} beam incident on an active target in the NA64 experiment at the CERN Super Proton Synchrotron and observed through the subsequent decay into a e^{+}e^{-} pair. With 5.4×10^{10} electrons on target, no evidence for such decays was found, allowing us to set first limits on the X-e^{-} coupling in the range 1.3×10^{-4}≲ε_{e}≲4.2×10^{-4} excluding part of the allowed parameter space. We also set new bounds on the mixing strength of photons with dark photons (A^{'}) from nonobservation of the decay A^{'}→e^{+}e^{-} of the bremsstrahlung A^{'} with a mass ≲23  MeV.

Published
2018
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16. First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process.

Author

Aghasyan M, Akhunzyanov R, Alexeev GD, Alexeev MG, Amoroso A, Andrieux V, Anfimov NV, Anosov V, Antoshkin A, Augsten K, Augustyniak W, Austregesilo A, Azevedo CDR, Badełek B, Balestra F, Ball M, Barth J, Beck R, Bedfer Y, Bernhard J, Bicker K, Bielert ER, Birsa R, Bodlak M, Bordalo P, Bradamante F, Bressan A, Büchele M, Chang WC, Chatterjee C, Chiosso M, Choi I, Chung SU, Cicuttin A, Crespo ML, Dalla Torre S, Dasgupta SS, Dasgupta S, Denisov OY, Dhara L, Donskov SV, Doshita N, Dreisbach C, Dünnweber W, Dziewiecki M, Efremov A, Eversheim PD, Faessler M, Ferrero A, Finger M, Finger M, Fischer H, Franco C, du Fresne von Hohenesche N, Friedrich JM, Frolov V, Fuchey E, Gautheron F, Gavrichtchouk OP, Gerassimov S, Giarra J, Giordano F, Gnesi I, Gorzellik M, Grasso A, Grosse Perdekamp M, Grube B, Grussenmeyer T, Guskov A, Hahne D, Hamar G, von Harrach D, Heinsius FH, Heitz R, Herrmann F, Horikawa N, d'Hose N, Hsieh CY, Huber S, Ishimoto S, Ivanov A, Ivanshin Y, Iwata T, Jary V, Joosten R, Jörg P, Kabuß E, Kerbizi A, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Koivuniemi JH, Kolosov VN, Kondo K, Königsmann K, Konorov I, Konstantinov VF, Kotzinian AM, Kouznetsov OM, Kral Z, Krämer M, Kremser P, Krinner F, Kroumchtein ZV, Kulinich Y, Kunne F, Kurek K, Kurjata RP, Kveton A, Lednev AA, Levillain M, Levorato S, Lian YS, Lichtenstadt J, Longo R, Maggiora A, Magnon A, Makins N, Makke N, Mallot GK, Marianski B, Martin A, Marzec J, Matoušek J, Matsuda H, Matsuda T, Meshcheryakov GV, Meyer M, Meyer W, Mikhailov YV, Mikhasenko M, Mitrofanov E, Mitrofanov N, Miyachi Y, Nagaytsev A, Nerling F, Neyret D, Nový J, Nowak WD, Nukazuka G, Nunes AS, Olshevsky AG, Orlov I, Ostrick M, Panzieri D, Parsamyan B, Paul S, Peng JC, Pereira F, Pešek M, Peshekhonov DV, Pierre N, Platchkov S, Pochodzalla J, Polyakov VA, Pretz J, Quaresma M, Quintans C, Ramos S, Regali C, Reicherz G, Riedl C, Rogacheva NS, Roskot M, Ryabchikov DI, Rybnikov A, Rychter A, Salac R, Samoylenko VD, Sandacz A, Santos C, Sarkar S, Savin IA, Sawada T, Sbrizzai G, Schiavon P, Schmidt K, Schmieden H, Schönning K, Seder E, Selyunin A, Shevchenko OY, 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, Takewaka S, Tasevsky M, Tessaro S, Terça G, Tessarotto F, Thiel A, Tomsa J, Tosello F, Tskhay V, Uhl S, Vauth A, Veloso J, Virius M, Vit M, Vondra J, Wallner S, Weisrock T, Wilfert M, Ter Wolbeek J, Zaremba K, Zavada P, Zavertyaev M, Zemlyanichkina E, Zhuravlev N, and Ziembicki M

Abstract

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190  GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3  GeV/c^{2} and 8.5  GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Published
2017
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17. Search for Invisible Decays of Sub-GeV Dark Photons in Missing-Energy Events at the CERN SPS.

Author

Banerjee D, Burtsev V, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dubinin F, Dusaev RR, Emmenegger S, Fabich A, Frolov VN, Gardikiotis A, Gninenko SN, Hösgen M, Kachanov VA, Karneyeu AE, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Myalkovskiy VV, Peshekhonov VD, Peshekhonov DV, Petuhov O, Polyakov VA, Radics B, Rubbia A, Samoylenko VD, Tikhomirov VO, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin B, Vasquez Arenas G, Ulloa P, Zhukov K, and Zioutas K

Abstract

We report on a direct search for sub-GeV dark photons (A^{'}), which might be produced in the reaction e^{-}Z→e^{-}ZA^{'} via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The dark photons would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75×10^{9} electrons on target. We set new limits on the γ-A^{'} mixing strength and exclude the invisible A^{'} with a mass ≲100  MeV as an explanation of the muon g_{μ}-2 anomaly.

Published
2017
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18. Observation of a New Narrow Axial-Vector Meson a1(1420).

Author

Adolph C, Akhunzyanov R, Alexeev MG, Alexeev GD, Amoroso A, Andrieux V, Anosov V, Austregesilo A, Azevedo C, Badełek B, Balestra F, Barth J, Beck R, Bedfer Y, Bernhard J, Bicker K, Bielert ER, Birsa R, Bisplinghoff J, Bodlak M, Boer M, Bordalo P, Bradamante F, Braun C, Bressan A, Büchele M, Burtin E, Chang WC, Chiosso M, Choi I, Chung SU, Cicuttin A, Crespo ML, Curiel Q, Dalla Torre S, Dasgupta SS, Dasgupta S, Denisov OY, Dhara L, Donskov SV, Doshita N, Dünnweber W, Duic V, Dziewiecki M, Efremov A, Eversheim PD, Eyrich W, Faessler M, Ferrero A, Finger M, Finger M, Fischer H, Franco C, du Fresne von Hohenesche N, Friedrich JM, Frolov V, Gautheron F, Gavrichtchouk OP, Gerassimov S, 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 FH, Herrmann F, Hinterberger F, Horikawa N, d'Hose N, Hsieh CY, Huber S, Ishimoto S, Ivanov A, Ivanshin Y, Iwata T, Jahn R, Jary V, Jörg P, Joosten R, Kabuß E, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Klimaszewski K, Koivuniemi JH, Kolosov VN, Kondo K, Königsmann K, Konorov I, Konstantinov VF, Kotzinian AM, Kouznetsov O, Krämer M, Kremser P, Krinner F, Kroumchtein ZV, Kuchinski N, Kunne F, Kurek K, Kurjata RP, Lednev AA, Lehmann A, Levillain M, Levorato S, Lichtenstadt J, Maggiora A, Magnon A, Makins N, Makke N, Mallot GK, Marchand C, Martin A, Marzec J, Matousek J, Matsuda H, Matsuda T, Meshcheryakov G, Meyer W, Michigami T, Mikhailov YV, Miyachi Y, Nagaytsev A, Nagel T, Nerling F, Neyret D, Nikolaenko VI, Novy J, Nowak WD, Nunes AS, Olshevsky AG, Orlov I, Ostrick M, Panzieri D, Parsamyan B, Paul S, Peng JC, Pereira F, Pesek M, Peshekhonov DV, Platchkov S, Pochodzalla J, Polyakov VA, Pretz J, Quaresma M, Quintans C, Ramos S, Regali C, Reicherz G, Riedl C, Rocco E, Rossiyskaya NS, Ryabchikov DI, Rychter A, Samoylenko VD, Sandacz A, Santos C, Sarkar S, Savin IA, Sbrizzai G, Schiavon P, Schmeing S, Schmidt K, Schmieden H, Schönning K, Schopferer S, Schlüter T, Selyunin A, Shevchenko OY, Silva L, Sinha L, Sirtl S, Slunecka M, Sozzi F, Srnka A, Stolarski M, Sulc M, Suzuki H, Szabelski A, Szameitat T, Sznajder P, Takekawa S, Ter Wolbeek J, Tessaro S, Tessarotto F, Thibaud F, Tskhay V, Uhl S, Veloso J, Virius M, Wallner S, Weisrock T, Wilfert M, Zaremba K, Zavertyaev M, Zemlyanichkina E, Ziembicki M, and Zink A

Abstract

The COMPASS Collaboration at CERN has measured diffractive dissociation of 190  GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++). We present a resonance-model study of a subset of the spin-density matrix selecting 3π states with J(PC)=2(++) and 4(++) decaying into ρ(770)π and with J(PC)=1(++) decaying into f0(980)π. We identify a new a1 meson with mass (1414(-13)(+15))  MeV/c2 and width (153(-23)(+8))  MeV/c2. Within the final states investigated in our analysis, we observe the new a1(1420) decaying only into f0(980)π, suggesting its exotic nature.

Published
2015
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19. Measurement of the charged-pion polarizability.

Author

Adolph C, Akhunzyanov R, Alexeev MG, Alexeev GD, Amoroso A, Andrieux V, Anosov V, Austregesilo A, Badełek B, Balestra F, Barth J, Baum G, Beck R, Bedfer Y, Berlin A, Bernhard J, Bicker K, Bieling J, Birsa R, Bisplinghoff J, Bodlak M, Boer M, Bordalo P, Bradamante F, Braun C, Bressan A, Büchele M, Burtin E, Capozza L, Chiosso M, Chung SU, Cicuttin A, Colantoni M, Crespo ML, Curiel Q, Dalla Torre S, Dasgupta SS, Dasgupta S, Denisov OY, Dinkelbach AM, Donskov SV, Doshita N, Duic V, Dünnweber W, Dziewiecki M, Efremov A, Elia C, Eversheim PD, Eyrich W, Faessler M, Ferrero A, Filin A, Finger M Jr, Finger M, Fischer H, Franco C, du Fresne von Hohenesche N, Friedrich JM, Frolov V, Gautheron F, Gavrichtchouk OP, Gerassimov S, Geyer R, Gnesi I, Gobbo B, Goertz S, Gorzellik M, Grabmüller S, Grasso A, Grube B, Grussenmeyer T, Guskov A, Guthörl T, Haas F, von Harrach D, Hahne D, Hashimoto R, Heinsius FH, Herrmann F, Hinterberger F, Höppner Ch, Horikawa N, d'Hose N, Huber S, Ishimoto S, Ivanov A, Ivanshin Y, Iwata T, Jahn R, Jary V, Jasinski P, Jörg P, Joosten R, Kabuss E, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Klimaszewski K, Koivuniemi JH, Kolosov VN, Kondo K, Königsmann K, Konorov I, Konstantinov VF, Kotzinian AM, Kouznetsov O, Krämer M, Kroumchtein ZV, Kuchinski N, Kuhn R, Kunne F, Kurek K, Kurjata RP, Lednev AA, Lehmann A, Levillain M, Levorato S, Lichtenstadt J, Maggiora A, Magnon A, Makke N, Mallot GK, Marchand C, Martin A, Marzec J, Matousek J, Matsuda H, Matsuda T, Meshcheryakov G, Meyer W, Michigami T, Mikhailov YV, Miyachi Y, Moinester MA, Nagaytsev A, Nagel T, Nerling F, Neubert S, Neyret D, Nikolaenko VI, Novy J, Nowak WD, Nunes AS, Olshevsky AG, Orlov I, Ostrick M, Panknin R, Panzieri D, Parsamyan B, Paul S, Peshekhonov D, Platchkov S, Pochodzalla J, Polyakov VA, Pretz J, Quaresma M, Quintans C, Ramos S, Regali C, Reicherz G, Rocco E, Rossiyskaya NS, Ryabchikov DI, Rychter A, Samoylenko VD, Sandacz A, Sarkar S, Savin IA, Sbrizzai G, Schiavon P, Schill C, Schlüter T, Schmidt K, Schmieden H, Schönning K, Schopferer S, Schott M, Shevchenko OY, Silva L, Sinha L, Sirtl S, Slunecka M, Sosio S, Sozzi F, Srnka A, Steiger L, Stolarski M, Sulc M, Sulej R, Suzuki H, Szabelski A, Szameitat T, Sznajder P, Takekawa S, ter Wolbeek J, Tessaro S, Tessarotto F, Thibaud F, Uhl S, Uman I, Virius M, Wang L, Weisrock T, Wilfert M, Windmolders R, Wollny H, Zaremba K, Zavertyaev M, Zemlyanichkina E, Ziembicki M, and Zink A

Abstract

The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015  (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4)  fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

Published
2015
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20. First measurement of chiral dynamics in π- γ → π- π- π+.

Author

Adolph C, Alekseev MG, Alexakhin VY, Alexandrov Y, Alexeev GD, Amoroso A, Antonov AA, Austregesilo A, Badełek B, Balestra F, Barth J, Baum G, Bedfer Y, Bernhard J, Bertini R, Bettinelli M, Bicker KA, Birsa R, Bisplinghoff J, Bordalo P, Bradamante F, Braun C, Bravar A, Bressan A, Burtin E, Chaberny D, Chiosso M, Chung SU, Cicuttin A, Crespo ML, Dalla Torre S, Das S, Dasgupta SS, Denisov OY, Dhara L, Donskov SV, Doshita N, Duic V, Dünnweber W, Dziewiecki M, Efremov A, Elia C, Eversheim PD, Eyrich W, Faessler M, Ferrero A, Filin A, Finger M, Finger M Jr, Fischer H, Franco C, du Fresne von Hohenesche N, Friedrich JM, Garfagnini R, Gautheron F, Gavrichtchouk OP, Gazda R, Gerassimov S, Geyer R, Giorgi M, Gnesi I, Gobbo B, Goertz S, Grabmüller S, Grasso A, Grube B, Gushterski R, Guskov A, Haas F, von Harrach D, Hasegawa T, Heinsius FH, Herrmann F, Hess C, Hinterberger F, Horikawa N, Höppner Ch, d'Hose N, Huber S, Ishimoto S, Ivanov O, Ivanshin Y, Iwata T, Jahn R, Jasinski P, Jegou G, Joosten R, Kabuss E, Kang D, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Klimaszewski K, Koblitz S, Koivuniemi JH, Kolosov VN, Kondo K, Königsmann K, Konorov I, Konstantinov VF, Korzenev A, Kotzinian AM, Kouznetsov O, Krämer M, Kroumchtein ZV, Kunne F, Kurek K, Lauser L, Lednev AA, Lehmann A, Levorato S, Lichtenstadt J, Maggiora A, Magnon A, Makke N, Mallot GK, Mann A, Marchand C, Martin A, Marzec J, Massmann F, Matsuda T, Meyer W, Michigami T, Mikhailov YV, Moinester MA, Morreale A, Mutter A, Nagaytsev A, Nagel T, Nerling F, Neubert S, Neyret D, Nikolaenko VI, Nowak WD, Nunes AS, Olshevsky AG, Ostrick M, Padee A, Panknin R, Panzieri D, Parsamyan B, Paul S, Perevalova E, Pesaro G, Peshekhonov DV, Piragino G, Platchkov S, Pochodzalla J, Polak J, Polyakov VA, Pontecorvo G, Pretz J, Quintans C, Rajotte JF, Ramos S, Rapatsky V, Reicherz G, Richter A, Rocco E, Rondio E, Rossiyskaya NS, Ryabchikov DI, Samoylenko VD, Sandacz A, Sapozhnikov MG, Sarkar S, Savin IA, Sbrizzai G, Schiavon P, Schill C, Schlüter T, Schmitt L, Schönning K, Schopferer S, Schröder W, Shevchenko OY, Siebert HW, Silva L, Sinha L, Sissakian AN, Slunecka M, Smirnov GI, Sosio S, Sozzi F, Srnka A, Stolarski M, Sulc M, Sulej R, Sznajder P, Takekawa S, Ter Wolbeek J, Tessaro S, Tessarotto F, Teufel A, Tkatchev LG, Uhl S, Uman I, Vandenbroucke M, Virius M, Vlassov NV, Windmolders R, Wiślicki W, Wollny H, Zaremba K, Zavertyaev M, Zemlyanichkina E, Ziembicki M, Zhuravlev N, and Zvyagin A

Abstract

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Published
2012
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21. Observation of a J(PC)=1-+ exotic resonance in diffractive dissociation of 190   GeV/c π- into π- π- π+.

Author

Alekseev MG, Alexakhin VY, Alexandrov Y, Alexeev GD, Amoroso A, Austregesilo A, Badełek B, Balestra F, Ball J, Barth J, Baum G, Bedfer Y, Bernhard J, Bertini R, Bettinelli M, Birsa R, Bisplinghoff J, Bordalo P, Bradamante F, Bravar A, Bressan A, Brona G, Burtin E, Bussa MP, Chapiro A, Chiosso M, Chung SU, Cicuttin A, Colantoni M, Crespo ML, Dalla Torre S, Dafni T, Das S, Dasgupta SS, Denisov OY, Dhara L, Diaz V, Dinkelbach AM, Donskov SV, Doshita N, Duic V, Dünnweber W, Efremov A, El Alaoui A, Eversheim PD, Eyrich W, Faessler M, Ferrero A, Finger M, Finger M Jr, Fischer H, Franco C, Friedrich JM, Garfagnini R, Gautheron F, Gavrichtchouk OP, Gazda R, Gerassimov S, Geyer R, Giorgi M, Gobbo B, Goertz S, Grabmüller S, Grajek OA, Grasso A, Grube B, Gushterski R, Guskov A, Haas F, von Harrach D, Hasegawa T, Heckmann J, Heinsius FH, Hermann R, Herrmann F, Hess C, Hinterberger F, Horikawa N, Höppner Ch, d'Hose N, Ilgner C, Ishimoto S, Ivanov O, Ivanshin Y, Iwata T, Jahn R, Jasinski P, Jegou G, Joosten R, Kabuss E, Kang D, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Klimaszewski K, Koblitz S, Koivuniemi JH, Kolosov VN, Komissarov EV, Kondo K, Königsmann K, Konopka R, Konorov I, Konstantinov VF, Korzenev A, Kotzinian AM, Kouznetsov O, Kowalik K, Krämer M, Kral A, Kroumchtein ZV, Kuhn R, Kunne F, Kurek K, Lauser L, Le Goff JM, Lednev AA, Lehmann A, Levorato S, Lichtenstadt J, Liska T, Maggiora A, Maggiora M, Magnon A, Mallot GK, Mann A, Marchand C, Marroncle J, Martin A, Marzec J, Massmann F, Matsuda T, Maximov AN, Meyer W, Michigami T, Mikhailov YV, Moinester MA, Mutter A, Nagaytsev A, Nagel T, Nassalski J, Negrini T, Nerling F, Neubert S, Neyret D, Nikolaenko VI, Olshevsky AG, Ostrick M, Padee A, Panknin R, Panzieri D, Parsamyan B, Paul S, Pawlukiewicz-Kaminska B, Perevalova E, Pesaro G, Peshekhonov DV, Piragino G, Platchkov S, Pochodzalla J, Polak J, Polyakov VA, Pontecorvo G, Pretz J, Quintans C, Rajotte JF, Ramos S, Rapatsky V, Reicherz G, Reggiani D, Richter A, Robinet F, Rocco E, Rondio E, Ryabchikov DI, Samoylenko VD, Sandacz A, Santos H, Sapozhnikov MG, Sarkar S, Savin IA, Sbrizzai G, Schiavon P, Schill C, Schlüter T, Schmitt L, Schopferer S, Schröder W, Shevchenko OY, Siebert HW, Silva L, Sinha L, Sissakian AN, Slunecka M, Smirnov GI, Sosio S, Sozzi F, Srnka A, Stolarski M, Sulc M, Sulej R, Takekawa S, Tessaro S, Tessarotto F, Teufel A, Tkatchev LG, Uhl S, Uman I, Venugopal G, Virius M, Vlassov NV, Vossen A, Weitzel Q, Windmolders R, Wiślicki W, Wollny H, Zaremba K, Zavertyaev M, Zemlyanichkina E, Ziembicki M, Zhao J, Zhuravlev N, and Zvyagin A

Abstract

The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190  GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1  GeV2/c2. The well-known resonances a1(1260), a2(1320), and π2(1670) are clearly observed. In addition, the data show a significant natural-parity exchange production of a resonance with spin-exotic quantum numbers J(PC)=1-+ at 1.66  GeV/c2 decaying to ρπ. The resonant nature of this wave is evident from the mass-dependent phase differences to the J(PC)=2-+ and 1++ waves. From a mass-dependent fit a resonance mass of (1660±10(-64)(+0))  MeV/c2 and a width of (269±21(-64)(+42))  MeV/c2 are deduced, with an intensity of (1.7±0.2)% of the total intensity.

Published
2010
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22. First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering.

Author

Alexakhin VY, Alexandrov Y, Alexeev GD, Amoroso A, Badełek B, Balestra F, Ball J, Baum G, Bedfer Y, Berglund P, Bernet C, Bertini R, Birsa R, Bisplinghoff J, Bradamante F, Bravar A, Bressan A, Burtin E, Bussa MP, Cerini L, Chapiro A, Cicuttin A, Colantoni M, Colavita AA, Costa S, Crespo ML, d'Hose N, Dalla Torre S, Dasgupta SS, De Masi R, Dedek N, Denisov OY, Dhara L, Diaz Kavka V, Dolgopolov AV, Donskov SV, Dorofeev VA, Doshita N, Duic V, Dünnweber W, Efremov A, Ehlers J, Eversheim PD, Eyrich W, Fabro M, Faessler M, Fauland P, Ferrero A, Ferrero L, Finger M, Finger M Jr, Fischer H, Franz J, Friedrich JM, Frolov V, Fuchs U, Garfagnini R, Gautheron F, Gavrichtchouk OP, Gerassimov S, Geyer R, Giorgi M, Gobbo B, Goertz S, Grajek OA, Grasso A, Grube B, Grünemaier A, Gustafsson K, Hannappel J, von Harrach D, Hasegawa T, Hedicke S, Heinsius FH, Hinterberger F, von Hodenberg M, Horikawa N, Horikawa S, Ijaduola RB, Ilgner C, Ishimoto S, Iwata T, Jahn R, Janata A, Joosten R, Jouravlev NI, Kabuss E, Kalinnikov V, Kang D, Karstens F, Kastaun W, Ketzer B, Khaustov GV, Khokhlov YA, Kisselev Y, Klein F, Koivuniemi JH, Kolosov VN, Komissarov EV, Kondo K, Königsmann K, Konoplyannikov AK, Konorov I, Konstantinov VF, Korentchenko AS, Korzenev A, Kotzinian AM, Koutchinski NA, Kowalik K, Kravchuk NP, Krivokhizhin GV, Kroumchtein ZV, Kuhn R, Kunne F, Kurek K, Lamanna M, Le Goff JM, Leberig M, Lichtenstadt J, Maggiora A, Maggiora M, Magnon A, Mallot GK, Manuilov IV, Marchand C, Marroncle J, Martin A, Marzec J, Matsuda T, Maximov AN, Medved KS, Meyer W, Mielech A, Mikhailov YV, Moinester MA, Nähle O, Nassalski J, Neyret DP, Nikolaenko VI, Nozdrin AA, Obraztsov VF, Olshevsky AG, Ostrick M, Padee A, Pagano P, Panebianco S, Panzieri D, Paul S, Pereira HD, Peshekhonov DV, Peshekhonov VD, Piragino G, Platchkov S, Platzer K, Pochodzalla J, Polyakov VA, Popov AA, Pretz J, Rebourgeard PC, Reicherz G, Reymann J, Rozhdestvensky AM, Rondio E, Sadovski AB, Saller E, Samoylenko VD, Sandacz A, Sans M, Sapozhnikov MG, Savin IA, Schiavon P, Schmidt T, Schmitt H, Schmitt L, Shishkin AA, Siebert H, Sinha L, Sissakian AN, Skachkova A, Slunecka M, Smirnov GI, Sugonyaev VP, Stinzing F, Sulej R, Takabayashi N, Tchalishev VV, Tessarotto F, Teufel A, Thers D, Tkatchev LG, Toeda T, Tretyak VI, Trousov S, Vlassov NV, Webb R, Weise E, Wiesmann M, Windmolders R, Wirth S, Wiślicki W, Zanetti AM, Zaremba K, Zhao J, Ziegler R, and Zvyagin A

Abstract

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Published
2005
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