V. A. Nikonov - St.Petersburg Nuclear Physics Institute

V. A. Nikonov
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Name
V. A. Nikonov
Affiliation
St.Petersburg Nuclear Physics Institute
City
Saint Petersburg
Country
Russia

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Nuclear Experiment (27)
 
High Energy Physics - Phenomenology (20)
 
High Energy Physics - Experiment (14)
 
Nuclear Theory (6)
 
Quantum Physics (1)
 
Mathematical Physics (1)
 
Mathematics - Mathematical Physics (1)

Publications Authored By V. A. Nikonov

2017May
Authors: D. Ho, P. Peng, C. Bass, P. Collins, A. D'Angelo, A. Deur, J. Fleming, C. Hanretty, T. Kageya, M. Khandaker, F. J. Klein, E. Klempt, V. Laine, M. M. Lowry, H. Lu, C. Nepali, V. A. Nikonov, T. O'Connell, A. M. Sandorfi, A. V. Sarantsev, R. A. Schumacher, I. I. Strakovsky, A. Švarc, N. K. Walford, X. Wei, C. S. Whisnant, R. L. Workman, I. Zonta, K. P. Adhikari, D. Adikaram, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, J. Ball, M. Bashkanov, M. Battaglieri, V. Batourine, I. Bedlinskiy, W. J. Briscoe, V. D. Burkert, D. S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P. L. Cole, M. Contalbrigo, V. Crede, N. Dashyan, E. De Sanctis, R. De Vita, C. Djalali, R. Dupre, A. El Alaoui, L. El Fassi, L. Elouadrhiri, G. Fedotov, S. Fegan, R. Fersch, A. Filippi, A. Fradi, Y. Ghandilyan, G. P. Gilfoyle, F. X. Girod, D. I. Glazier, C. Gleason, W. Gohn, E. Golovatch, R. W. Gothe, K. A. Griffioen, M. Guidal, L. Guo, H. Hakobyan, N. Harrison, K. Hicks, M. Holtrop, S. M. Hughes, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, D. Jenkins, H. Jiang, H. S. Jo, K. Joo, S. Joosten, D. Keller, G. Khachatryan, A. Kim, W. Kim, A. Klein, V. Kubarovsky, S. V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, I . J . D. MacGregor, N. Markov, B. McKinnon, T. Mineeva, V. Mokeev, R. A. Montgomery, A Movsisyan, C. Munoz Camacho, G. Murdoch, S. Niccolai, G. Niculescu, M. Osipenko, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, O. Pogorelko, J. W. Price, S. Procureur, D. Protopopescu, M. Ripani, D. Riser, B. G. Ritchie, A. Rizzo, G. Rosner, F. Sabatié, C. Salgado, Y. G. Sharabian, Iu. Skorodumina, G. D. Smith, D. I. Sober, D. Sokhan, N. Sparveris, S. Strauch, Ye Tian, B. Torayev, M. Ungaro, H. Voskanyan, D. P. Watts, M. H. Wood, N. Zachariou, J. Zhang, Z. W. Zhao

We report the first beam-target double-polarization asymmetries in the $\gamma + n(p) \rightarrow \pi^- + p(p)$ reaction spanning the nucleon resonance region from invariant mass $W$= $1500$ to $2300$ MeV. Circularly polarized photons and longitudinally polarized deuterons in $H\!D$ have been used with the CLAS detector at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the {\it{E}} polarization observable for an effective neutron target. Read More

Photoproduction of $\eta$ mesons from neutrons} \abstract{Results from measurements of the photoproduction of $\eta$ mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the $\eta\to3\pi^{0}\to6\gamma$ decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. Read More

2017Mar
Affiliations: 1Joint Institute of Nuclear Research, 141980 Dubna, Russia, 2Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 3LabCAF. F. Física, Univ. de Santiago de Compostela, 15706 Santiago de Compostela, Spain, 4Joint Institute of Nuclear Research, 141980 Dubna, Russia, 5Physik Department E12, Technische Universität München, 85748 Garching, Germany, 6LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal, 7Physik Department E12, Technische Universität München, 85748 Garching, Germany, 8Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, 91406 Orsay Cedex, France, 9LabCAF. F. Física, Univ. de Santiago de Compostela, 15706 Santiago de Compostela, Spain, 10Joint Institute of Nuclear Research, 141980 Dubna, Russia, 11Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 12Physik Department E12, Technische Universität München, 85748 Garching, Germany, 13Physik Department E12, Technische Universität München, 85748 Garching, Germany, 14Joint Institute of Nuclear Research, 141980 Dubna, Russia, 15Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, 95125 Catania, Italy, 16LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal, 17Physik Department E12, Technische Universität München, 85748 Garching, Germany, 18Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 19Technische Universität Darmstadt, 64289 Darmstadt, Germany, 20LabCAF. F. Física, Univ. de Santiago de Compostela, 15706 Santiago de Compostela, Spain, 21Physik Department E12, Technische Universität München, 85748 Garching, Germany, 22Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 23Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 24Technische Universität Darmstadt, 64289 Darmstadt, Germany, 25Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 26Technische Universität Darmstadt, 64289 Darmstadt, Germany, 27GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 28Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, 91406 Orsay Cedex, France, 29GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 30Joint Institute of Nuclear Research, 141980 Dubna, Russia, 31Istituto Nazionale di Fisica Nucleare, Sezione di Milano, 20133 Milano, Italy, 32Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 33Physik Department E12, Technische Universität München, 85748 Garching, Germany, 34Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany, 35Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 36GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 37GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 38GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 39Technische Universität Darmstadt, 64289 Darmstadt, Germany, 40Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany, 41Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 42Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 43Physik Department E12, Technische Universität München, 85748 Garching, Germany, 44Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 45II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392 Giessen, Germany, 46Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 47Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 48Joint Institute of Nuclear Research, 141980 Dubna, Russia, 49Physik Department E12, Technische Universität München, 85748 Garching, Germany, 50GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 51Physik Department E12, Technische Universität München, 85748 Garching, Germany, 52Institute of Theoretical and Experimental Physics, 117218 Moscow, Russia, 53Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, 91406 Orsay Cedex, France, 54LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal, 55Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 56Physik Department E12, Technische Universität München, 85748 Garching, Germany, 57LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal, 58Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 59II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392 Giessen, Germany, 60Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 61Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 62Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 63Physik Department E12, Technische Universität München, 85748 Garching, Germany, 64Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany, 65Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 66Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 67Department of Physics, University of Cyprus, 1678 Nicosia, Cyprus, 68GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 69Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 70GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 71Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 72Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, 91406 Orsay Cedex, France, 73Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 74Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 75Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia, 76Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 77Lawrence Berkeley National Laboratory, Berkeley, USA, 78GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 79Physik Department E12, Technische Universität München, 85748 Garching, Germany, 80Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 81Dipartimento di Fisica and INFN, Università di Torino, 10125 Torino, Italy, 82II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392 Giessen, Germany, 83Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 84Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 85GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 86Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 87Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany, 88Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 89GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 90Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059 Kraków, Poland, 91Department of Physics, University of Cyprus, 1678 Nicosia, Cyprus, 92Joint Institute of Nuclear Research, 141980 Dubna, Russia, 93Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068 Rez, Czech Republic, 94Physik Department E12, Technische Universität München, 85748 Garching, Germany, 95Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany, 96Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany, 97GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany, 98Joint Institute of Nuclear Research, 141980 Dubna, Russia, 99NRC "Kurchatov Institute", PNPI, 188300, Gatchina, Russia, 100NRC "Kurchatov Institute", PNPI, 188300, Gatchina, Russia

Baryon resonance production in proton-proton collisions at a kinetic beam energy of 1.25 GeV is investigated. The multi-differential data were measured by the HADES collaboration. Read More

2017Mar
Authors: P. Collins, B. G. Ritchie, M. Dugger, A. V. Anisovich, M. Döring, E. Klempt, V. A. Nikonov, D. Rönchen, D. Sadasivan, A. Sarantsev, K. P. Adhikaria, Z. Akbar, M. J. Amaryana, S. Anefalos Pereira, H. Avakiana, J. Ball, I. Balossino, M. Bashkanova, M. Battaglieri, I. Bedlinskiy, A. S. Bisellik, W. J. Briscoe, W. K. Brooks, V. D. Burkert, Frank Thanh Cao, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P. L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J. A. Fleming, Y. Ghandilyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, D. I. Glazier, C. Gleason, E. Golovatch, R. W. Gothe, K. A. Griffioen, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, D. Heddle, K. Hicks, M. Holtrop, S. M. Hughes, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, D. Jenkins, H. S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F. J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I. J. D. MacGregor, N. Markov, B. McKinnon, C. A. Meyer, M. Mirazita, V. Mokeev, R. A. Montgomery, A Movsisyan, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A. I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J. W. Price, Y. Prok, D. Protopopescu, B. A. Raue, M. Ripani, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, R. A. Schumacher, Y. G. Sharabian, Iu. Skorodumina, G. D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, I. I. Strakovsky, S. Strauch, M. Taiuti, Ye Tian, B. Torayev, M. Ungaro, H. Voskanyan, E. Voutier, N. K. Walford, X. Wei, N. Zachariou, J. Zhang

Measurements of the linearly-polarized photon beam asymmetry $\Sigma$ for photoproduction from the proton of $\eta$ and $\eta^\prime$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $\gamma p \to \eta p$ reaction for incident photon energies from 1. Read More

The new data on the elastic $pp$ and single pion production reaction $pp\to pn \pi^{+}$ taken at the incident proton momentum 1683 MeV/c are presented. The data on the $pp\to pn \pi^{+}$ reaction are compared with predictions from the OPE model. To extract contributions of the leading partial waves the single pion production data are analyzed in the framework of the event-by-event maximum likelihood method together with the data measured earlier. Read More

The helicity-dependent observable $E$ for the reaction $\gamma d\to \eta n (p)$ with a spectator proton was recently measured by the A2 Collaboration at MAMI in Mainz. The data were interpreted as further evidence for a narrow resonance with spin and parity $J^P=1/2^+$ ($P_{11}$ wave). However, a full partial wave analysis without any narrow resonance leads to an excellent description of the data, imposing a narrow resonance with the properties suggested by the A2 Collaboration leads to a significant deterioration of the fit quality: there is no need for a narrow resonance. Read More

New data on pion-photoproduction off the proton have been included in the partial wave analyses Bonn-Gatchina and SAID and in the dynamical coupled-channel approach J\"ulich-Bonn. All reproduce the recent new data well: the double polarization data for E, G, H, P and T in $\gamma p \to \pi^0 p$ from ELSA, the beam asymmetry $\Sigma$ for $\gamma p \to \pi^0 p$ and $\pi^+ n$ from Jefferson Laboratory, and the precise new differential cross section and beam asymmetry data $\Sigma$ for $\gamma p \to \pi^0 p$ from MAMI. The new fit results for the multipoles are compared with predictions not taking into account the new data. Read More

Comparative analysis of the interplay of hadron and Coulomb interactions in $pp^\pm$ scattering amplitudes is performed in a broad energy interval, $\sqrt{s}=1-10^6$ TeV, for two extreme cases: for the asymptotic interactions of hadrons in black disk and resonant disk modes. The interactions are discussed in terms of the $K$-matrix function technique. In the asymptotic regime the real part of the hadronic amplitude is concentrated in both cases on the boundary of the disks in the impact parameter space but the LHC energy region is not asymptotic for the resonant disk mode that lead to a specific interplay of hadronic and coulombic amplitudes. Read More

We study the interplay of hadronic and Coulomb interactions for $pp$ scattering at LHC energies on the basis of the previous determination of the real part of the amplitude [{\it V.V. Anisovich, V. Read More

Data on the reaction $\gamma p\to \omega p$ with $\omega\to\pi^0\gamma$, taken with unpolarized or polarized beams in combination with an unpolarized or polarized proton-target, were analyzed within the Bonn-Gatchina (BnGa) partial wave analysis. Differential cross sections, several spin density matrix elements, the beam asymmetry $\Sigma$, the normalized helicity difference $E$, and the correlation $G$ between linear photon and longitudinal target polarization were included in a large data base on pion and photo-induced reactions. The data on $\omega$ photoproduction are used to determine twelve $N^*\to N\omega$ branching ratios; most of these are determined for the first time. Read More

On the basis of requirements of unitarity and analyticity we analyze the real and imaginary parts of the $pp^\pm$ scattering amplitudes at recent ultrahigh energies, 1-100 TeV. The predictions for the region $\sqrt s > 100$ TeV and ${\bf q}^2<0.4$ GeV$^2$ are given supposing the black disk asymptotic regime. Read More

2015Jun
Affiliations: 1The CBELSA/TAPS Collaboration, 2The CBELSA/TAPS Collaboration, 3The CBELSA/TAPS Collaboration, 4The CBELSA/TAPS Collaboration, 5The CBELSA/TAPS Collaboration, 6The CBELSA/TAPS Collaboration, 7The CBELSA/TAPS Collaboration, 8The CBELSA/TAPS Collaboration, 9The CBELSA/TAPS Collaboration, 10The CBELSA/TAPS Collaboration, 11The CBELSA/TAPS Collaboration, 12The CBELSA/TAPS Collaboration, 13The CBELSA/TAPS Collaboration, 14The CBELSA/TAPS Collaboration, 15The CBELSA/TAPS Collaboration, 16The CBELSA/TAPS Collaboration, 17The CBELSA/TAPS Collaboration, 18The CBELSA/TAPS Collaboration, 19The CBELSA/TAPS Collaboration, 20The CBELSA/TAPS Collaboration, 21The CBELSA/TAPS Collaboration, 22The CBELSA/TAPS Collaboration, 23The CBELSA/TAPS Collaboration, 24The CBELSA/TAPS Collaboration, 25The CBELSA/TAPS Collaboration, 26The CBELSA/TAPS Collaboration, 27The CBELSA/TAPS Collaboration, 28The CBELSA/TAPS Collaboration, 29The CBELSA/TAPS Collaboration, 30The CBELSA/TAPS Collaboration, 31The CBELSA/TAPS Collaboration, 32The CBELSA/TAPS Collaboration, 33The CBELSA/TAPS Collaboration, 34The CBELSA/TAPS Collaboration, 35The CBELSA/TAPS Collaboration, 36The CBELSA/TAPS Collaboration, 37The CBELSA/TAPS Collaboration, 38The CBELSA/TAPS Collaboration, 39The CBELSA/TAPS Collaboration, 40The CBELSA/TAPS Collaboration, 41The CBELSA/TAPS Collaboration, 42The CBELSA/TAPS Collaboration, 43The CBELSA/TAPS Collaboration, 44The CBELSA/TAPS Collaboration, 45The CBELSA/TAPS Collaboration, 46The CBELSA/TAPS Collaboration, 47The CBELSA/TAPS Collaboration, 48The CBELSA/TAPS Collaboration, 49The CBELSA/TAPS Collaboration, 50The CBELSA/TAPS Collaboration, 51The CBELSA/TAPS Collaboration, 52The CBELSA/TAPS Collaboration, 53The CBELSA/TAPS Collaboration, 54The CBELSA/TAPS Collaboration, 55The CBELSA/TAPS Collaboration, 56The CBELSA/TAPS Collaboration, 57The CBELSA/TAPS Collaboration, 58The CBELSA/TAPS Collaboration, 59The CBELSA/TAPS Collaboration, 60The CBELSA/TAPS Collaboration, 61The CBELSA/TAPS Collaboration, 62The CBELSA/TAPS Collaboration, 63The CBELSA/TAPS Collaboration, 64The CBELSA/TAPS Collaboration, 65The CBELSA/TAPS Collaboration, 66The CBELSA/TAPS Collaboration, 67The CBELSA/TAPS Collaboration, 68The CBELSA/TAPS Collaboration, 69The CBELSA/TAPS Collaboration, 70The CBELSA/TAPS Collaboration, 71The CBELSA/TAPS Collaboration, 72The CBELSA/TAPS Collaboration, 73The CBELSA/TAPS Collaboration, 74The CBELSA/TAPS Collaboration, 75The CBELSA/TAPS Collaboration, 76The CBELSA/TAPS Collaboration, 77The CBELSA/TAPS Collaboration, 78The CBELSA/TAPS Collaboration, 79The CBELSA/TAPS Collaboration

Data on the polarization observables T, P, and H for the reaction $\gamma p\to p\pi^0$ are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. Read More

The first measurements of the beam-target-helicity-asymmetries $E$ and $G$ in the photoproduction of $\omega$-mesons off protons at the CBELSA/TAPS experiment are reported. $E$ ($G$) was measured using circularly (linearly) polarised photons and a longitudinally polarised target. $E$ was measured over the photon energy range from close to threshold ($E_\gamma = 1108$~MeV) to $E_\gamma = 2300$~MeV and $G$ at a single energy interval of $1108 < E_\gamma <1300$~MeV. Read More

We report a partial-wave analysis of new data on the double-polarization variable $E$ for the reactions $\gamma p\to \pi^+ n$ and $\gamma p\to \pi^0 p$ and of further data published earlier. The analysis within the Bonn-Gatchina (BnGa) formalism reveals evidence for a poorly known baryon resonance, the one-star $\Delta(2200)7/2^-$. This is the lowest-mass $\Delta^*$ resonance with spin-parity $J^P=7/2^-$. Read More

2015Mar
Authors: S. Strauch1, W. J. Briscoe2, M. Döring3, E. Klempt4, V. A. Nikonov5, E. Pasyuk6, D. Rönchen7, A. V. Sarantsev8, I. Strakovsky9, R. Workman10, K. P. Adhikari11, D. Adikaram12, M. D. Anderson13, S. Anefalos Pereira14, A. V. Anisovich15, R. A. Badui16, J. Ball17, V. Batourine18, M. Battaglieri19, I. Bedlinskiy20, N. Benmouna21, A. S. Biselli22, J. Brock23, W. K. Brooks24, V. D. Burkert25, T. Cao26, C. Carlin27, D. S. Carman28, A. Celentano29, S. Chandavar30, G. Charles31, L. Colaneri32, P. L. Cole33, N. Compton34, M. Contalbrigo35, O. Cortes36, V. Crede37, N. Dashyan38, A. D'Angelo39, R. De Vita40, E. De Sanctis41, A. Deur42, C. Djalali43, M. Dugger44, R. Dupre45, H. Egiyan46, A. El Alaoui47, L. El Fassi48, L. Elouadrhiri49, P. Eugenio50, G. Fedotov51, S. Fegan52, A. Filippi53, J. A. Fleming54, T. A. Forest55, A. Fradi56, N. Gevorgyan57, Y. Ghandilyan58, K. L. Giovanetti59, F. X. Girod60, D. I. Glazier61, W. Gohn62, E. Golovatch63, R. W. Gothe64, K. A. Griffioen65, M. Guidal66, L. Guo67, K. Hafidi68, H. Hakobyan69, C. Hanretty70, N. Harrison71, M. Hattawy72, K. Hicks73, D. Ho74, M. Holtrop75, S. M. Hughes76, Y. Ilieva77, D. G. Ireland78, B. S. Ishkhanov79, E. L. Isupov80, D. Jenkins81, H. Jiang82, H. S. Jo83, K. Joo84, S. Joosten85, C. D. Keith86, D. Keller87, G. Khachatryan88, M. Khandaker89, A. Kim90, W. Kim91, A. Klein92, F. J. Klein93, V. Kubarovsky94, S. E. Kuhn95, P. Lenisa96, K. Livingston97, H. Y. Lu98, I . J . D. MacGregor99, N. Markov100, B. McKinnon101, D. G. Meekins102, C. A. Meyer103, V. Mokeev104, R. A. Montgomery105, C. I. Moody106, H. Moutarde107, A Movsisyan108, E. Munevar109, C. Munoz Camacho110, P. Nadel-Turonski111, L. A. Net112, S. Niccolai113, G. Niculescu114, I. Niculescu115, M. Osipenko116, A. I. Ostrovidov117, K. Park118, P. Peng119, W. Phelps120, J. J. Phillips121, S. Pisano122, O. Pogorelko123, S. Pozdniakov124, J. W. Price125, S. Procureur126, Y. Prok127, D. Protopopescu128, A. J. R. Puckett129, B. A. Raue130, M. Ripani131, B. G. Ritchie132, A. Rizzo133, G. Rosner134, P. Roy135, F. Sabatié136, C. Salgado137, D. Schott138, R. A. Schumacher139, E. Seder140, M. L. Seely141, I Senderovich142, Y. G. Sharabian143, A. Simonyan144, Iu. Skorodumina145, G. D. Smith146, D. I. Sober147, D. Sokhan148, N. Sparveris149, P. Stoler150, S. Stepanyan151, V. Sytnik152, M. Taiuti153, Ye Tian154, A. Trivedi155, R. Tucker156, M. Ungaro157, H. Voskanyan158, E. Voutier159, N. K. Walford160, D. P. Watts161, X. Wei162, M. H. Wood163, N. Zachariou164, L. Zana165, J. Zhang166, Z. W. Zhao167, I. Zonta168
Affiliations: 1The CLAS Collaboration, 2The CLAS Collaboration, 3The CLAS Collaboration, 4The CLAS Collaboration, 5The CLAS Collaboration, 6The CLAS Collaboration, 7The CLAS Collaboration, 8The CLAS Collaboration, 9The CLAS Collaboration, 10The CLAS Collaboration, 11The CLAS Collaboration, 12The CLAS Collaboration, 13The CLAS Collaboration, 14The CLAS Collaboration, 15The CLAS Collaboration, 16The CLAS Collaboration, 17The CLAS Collaboration, 18The CLAS Collaboration, 19The CLAS Collaboration, 20The CLAS Collaboration, 21The CLAS Collaboration, 22The CLAS Collaboration, 23The CLAS Collaboration, 24The CLAS Collaboration, 25The CLAS Collaboration, 26The CLAS Collaboration, 27The CLAS Collaboration, 28The CLAS Collaboration, 29The CLAS Collaboration, 30The CLAS Collaboration, 31The CLAS Collaboration, 32The CLAS Collaboration, 33The CLAS Collaboration, 34The CLAS Collaboration, 35The CLAS Collaboration, 36The CLAS Collaboration, 37The CLAS Collaboration, 38The CLAS Collaboration, 39The CLAS Collaboration, 40The CLAS Collaboration, 41The CLAS Collaboration, 42The CLAS Collaboration, 43The CLAS Collaboration, 44The CLAS Collaboration, 45The CLAS Collaboration, 46The CLAS Collaboration, 47The CLAS Collaboration, 48The CLAS Collaboration, 49The CLAS Collaboration, 50The CLAS Collaboration, 51The CLAS Collaboration, 52The CLAS Collaboration, 53The CLAS Collaboration, 54The CLAS Collaboration, 55The CLAS Collaboration, 56The CLAS Collaboration, 57The CLAS Collaboration, 58The CLAS Collaboration, 59The CLAS Collaboration, 60The CLAS Collaboration, 61The CLAS Collaboration, 62The CLAS Collaboration, 63The CLAS Collaboration, 64The CLAS Collaboration, 65The CLAS Collaboration, 66The CLAS Collaboration, 67The CLAS Collaboration, 68The CLAS Collaboration, 69The CLAS Collaboration, 70The CLAS Collaboration, 71The CLAS Collaboration, 72The CLAS Collaboration, 73The CLAS Collaboration, 74The CLAS Collaboration, 75The CLAS Collaboration, 76The CLAS Collaboration, 77The CLAS Collaboration, 78The CLAS Collaboration, 79The CLAS Collaboration, 80The CLAS Collaboration, 81The CLAS Collaboration, 82The CLAS Collaboration, 83The CLAS Collaboration, 84The CLAS Collaboration, 85The CLAS Collaboration, 86The CLAS Collaboration, 87The CLAS Collaboration, 88The CLAS Collaboration, 89The CLAS Collaboration, 90The CLAS Collaboration, 91The CLAS Collaboration, 92The CLAS Collaboration, 93The CLAS Collaboration, 94The CLAS Collaboration, 95The CLAS Collaboration, 96The CLAS Collaboration, 97The CLAS Collaboration, 98The CLAS Collaboration, 99The CLAS Collaboration, 100The CLAS Collaboration, 101The CLAS Collaboration, 102The CLAS Collaboration, 103The CLAS Collaboration, 104The CLAS Collaboration, 105The CLAS Collaboration, 106The CLAS Collaboration, 107The CLAS Collaboration, 108The CLAS Collaboration, 109The CLAS Collaboration, 110The CLAS Collaboration, 111The CLAS Collaboration, 112The CLAS Collaboration, 113The CLAS Collaboration, 114The CLAS Collaboration, 115The CLAS Collaboration, 116The CLAS Collaboration, 117The CLAS Collaboration, 118The CLAS Collaboration, 119The CLAS Collaboration, 120The CLAS Collaboration, 121The CLAS Collaboration, 122The CLAS Collaboration, 123The CLAS Collaboration, 124The CLAS Collaboration, 125The CLAS Collaboration, 126The CLAS Collaboration, 127The CLAS Collaboration, 128The CLAS Collaboration, 129The CLAS Collaboration, 130The CLAS Collaboration, 131The CLAS Collaboration, 132The CLAS Collaboration, 133The CLAS Collaboration, 134The CLAS Collaboration, 135The CLAS Collaboration, 136The CLAS Collaboration, 137The CLAS Collaboration, 138The CLAS Collaboration, 139The CLAS Collaboration, 140The CLAS Collaboration, 141The CLAS Collaboration, 142The CLAS Collaboration, 143The CLAS Collaboration, 144The CLAS Collaboration, 145The CLAS Collaboration, 146The CLAS Collaboration, 147The CLAS Collaboration, 148The CLAS Collaboration, 149The CLAS Collaboration, 150The CLAS Collaboration, 151The CLAS Collaboration, 152The CLAS Collaboration, 153The CLAS Collaboration, 154The CLAS Collaboration, 155The CLAS Collaboration, 156The CLAS Collaboration, 157The CLAS Collaboration, 158The CLAS Collaboration, 159The CLAS Collaboration, 160The CLAS Collaboration, 161The CLAS Collaboration, 162The CLAS Collaboration, 163The CLAS Collaboration, 164The CLAS Collaboration, 165The CLAS Collaboration, 166The CLAS Collaboration, 167The CLAS Collaboration, 168The CLAS Collaboration

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\vec \gamma \vec p \to \pi^+n$, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2. Read More

The recent precise experimental results for the photoproduction of $\eta$-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled channel model. The main result is that the narrow structure observed in the excitation function of $\gamma n \rightarrow n\eta$ can be reproduced fully with a particular interference pattern in the $J^P=1/2^-$ partial wave. Introduction of the narrow resonance $N(1685)$ with the properties reported in earlier publications deteriorates the quality of the fit. Read More

Central production of lepton-lepton pairs ($e^+e^-$ and $\mu^+\mu^-$) and heavy quark composite states (charmonia and bottomonia) in diffractive proton collisions (proton momenta transferred ${|\bf q_\perp}|\sim m/\ln s$) are studied at ultrahigh energies ($\ln{s}>>1$), where $\sigma_{tot}(pp^\pm)\sim\ln^N s$ with $1\la N\la 2$. The $pp^\pm$-rescattering corrections, which are not small, are calculated in terms of the $K$-matrix approach modified for ultrahigh energies. Two versions of hadron interactions are considered in detail: the growth (i) $\sigma_{tot}(pp^\pm)\sim\ln^2 s$, $\sigma_{inel}(pp^\pm)\sim\ln^2 s$ within the black disk mode and (ii) $\sigma_{tot}(pp^\pm)\sim\ln^2 s$, $\sigma_{inel}(pp^\pm)\sim\ln s$ within the resonant disk mode. Read More

The analysis of current ultrahigh energy data for hadronic total cross sections and diffractive scattering cross sections points to a steady growth of the optical density with energy for elastic scattering amplitudes in the impact parameter space, $b$. At LHC energy the profile function of the $pp$-scattering amplitude, $T(b)$, reaches the black disk limit at small $b$. Two scenarios are possible at larger energies, $\sqrt{s}\ga 100$ TeV. Read More

Diffractive production is considered in the ultrahigh energy region where pomeron exchange amplitudes are transformed into black disk ones due to rescattering corrections. The corresponding corrections in hadron reactions $h_1+h_3\to h_1+h_2+h_3$ with small momenta transferred ($q^2_{1\to 1}\sim m^2/\ln^2s$, $q^2_{3\to 3}\sim m^2/\ln^2s$) are calculated in terms of the $K$-matrix technique modified for ultrahigh energies. Small values of the momenta transferred are crucial for introducing equations for amplitudes. Read More

New data on the polarization observables T, P, and H for the reaction $\gamma p \to p\pi^0$ are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. Read More

The reaction $\gamma \, p \rightarrow K^0_S\,\Sigma^+$ is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to $E_\gamma = 2250$ MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay $\Sigma^+ \rightarrow p \pi^0$ up to $E_\gamma = 1650$ MeV. Read More

Using all recent data on the differential cross sections and spin observables for the reaction $\gamma p \to K^+ \Lambda$, an energy-independent partial-wave analysis is performed. The analysis requires multipoles up to $L = 2$; there is no evidence that the fit requires multipoles with $L=3$. At present the available data allow us to extract the dominant multipoles only. Read More

The LHC energies are those at which the asymptotic regime in hadron-hadron diffractive collisions ($pp,\pi p,\pi\pi$) might be switched on. Based on results of the Dakhno-Nikonov eikonal model which is a generalization of the Good-Walker eikonal approach for a continuous set of channels, we present a picture for transformation of the constituent quark mode to the black disk one. In the black disk mode ($\sqrt s \geq 10$ TeV) we have a growth of the logarithm squared type for total and elastic cross sections, $\sigma_{tot}\sim\ln^2s$ and $\sigma_{el}\sim\ln^2s$, and $(\tau={\bf q}_\perp^2\sigma_{tot})$-scaling for diffractive scattering and diffractive dissociation of hadrons. Read More

The group theoretical description of the three-particle problem provides successful techniques for the solution of different questions. We present here a review of this approach. Read More

It is shown that the narrow structure observed in the excitation function of $\eta$ photoproduction off the Neutron originates from the interference of the two $S_{11}$ resonances. Read More

The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300\,MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed which are traced to differences in the helicity amplitudes of well known and established resonances. Read More

Ambiguities of the signs of $N\to \Sigma K$ coupling constants are studied in a multichannel partial wave analysis of a large body of pion and photo-induced reactions. It is shown that the signs are not free from some ambiguities, and further experimental data are needed. Data on the reactions $\pi^+p\to \Sigma^+K^+$ and $\gamma p\to K^+\Sigma^0$ define rather well the isospin 3/2 contributions to these channels. Read More

Using the pre-LHC and LHC data for $\pi p$ and $pp$ diffractive collisions we study the ultrahigh energy asymptotic regime in the framework of the black disk picture. The black disk picture, being constrained by the s-channel unitarity condition and the $t$-channel analyticity, gives rather definite predictions for diffractive processes increasing with the energy. To deal with the data, we consider the Dakhno-Nikonov eikonal model which predicts a growth of the $\ln^2s$ type for total and elastic cross sections and $(\tau={\bf q}_\perp^2\ln^2s)$-scaling for diffractive scattering and diffractive dissociation of hadrons. Read More

Measurements of $\gamma p \rightarrow K^{+} \Lambda$ and $\gamma p \rightarrow K^{+} \Sigma^0$ cross-sections have been obtained with the photon tagging facility and the Crystal Ball calorimeter at MAMI-C. The measurement uses a novel $K^+$ meson identification technique in which the weak decay products are characterized using the energy and timing characteristics of the energy deposit in the calorimeter, a method that has the potential to be applied at many other facilities. The fine center-of-mass energy ($W$) resolution and statistical accuracy of the new data results in a significant impact on partial wave analyses aiming to better establish the excitation spectrum of the nucleon. Read More

Amplitudes for the reaction $\pi^-p\to \Lambda K^0$ are reconstructed from data on the differential cross section $d\sigma/d\Omega$, the recoil polarization $P$, and on the spin rotation parameter $\beta$. At low energies, no data on $\beta$ exist, resulting in ambiguities. An approximation using $S$ and $P$ waves leads only to a fair description of the data on $d\sigma/d\Omega$ and $P$; in this case, there are two sets of amplitudes. Read More

Proton-proton total and elastic cross sections are considered in the Dakhno-Nikonov eikonal model [L.G. Dakhno, V. Read More

The helicity amplitudes $A^{1/2}_n$ and $A^{3/2}_n$ for the photoexcitation of nucleon resonances off neutrons are determined in a multi-channel partial-wave analysis. Read More

The first measurement is reported of the double-polarization observable G in photoproduction of neutral pions off protons, covering the photon energy range from 620 to 1120 MeV and the full solid angle. G describes the correlation between the photon polarization plane and the scattering plane for protons polarized along the direction of the incoming photon. The observable is highly sensitive to contributions from baryon resonances. Read More

Pion and photo-induced inelastic reactions off protons are studied in a multichannel partial-wave analysis. Properties of nucleon and $\Delta$ resonances are derived and compared to previous analyses. Amplitudes are shown for transitions to $N\eta$, $\Lambda K$, and $\Sigma K$ final states. Read More

Properties of nucleon and $\Delta$ resonances are derived from a multichannel partial wave analysis. The statistical significance of pion and photo-induced inelastic reactions off protons are studied in a multichannel partial-wave analysis. Read More

Results from a multi-channel partial wave analysis of elastic and inelastic $\pi N$ and $\gamma N$ induced reactions are presented. The analysis evidences the existence of a spin-quartet of nucleon resonances with total angular momenta $J^P=1/2^+,.. Read More

Evidence is reported for two nucleon resonances with spin-parity $J^P=1/2^-$ and $J^P=3/2^-$ at a mass just below 1.9\,GeV. The evidence is derived from a coupled-channel analysis of a large number of pion and photo-produced reactions. Read More

The status of light I=0, J^{PC}=2^{++} and 0^{++} mesons is discussed, particularly the separation of n-nbar and s-sbar states. They fall into a simple scheme except for f_2(1810). A case is made that this has been confused with the f_0(1790). Read More

A combined analysis is reported of 3pizero, pizero-eta and pizero-etaprime data in the mass range 1960 to 2410 MeV. This analysis is made consistent also with eta-eta-pizero data, reported separately. The analysis requires s-channel resonances with a spectrum close to that published earlier for C = +1 states with I = 0; masses for I=1 states are lower on average by 20 MeV. Read More

A partial wave analysis of pbar-p -> eta-eta-pizero data from the Crystal Barrel experiment is made in terms of s-channel resonances. The decay channels a_0(980)-eta, f_0(1770)-pi and f_0(2105)-pi provide evidence for two I = 1 J^{PC} = 0^{-+} resonances. The first has mass M =2360 +- 25 MeV and width Gamma = 300^{+100}_{-50} MeV, and the second M =2070 \pm 35 MeV, Gamma = 310^{+100}_{-50} MeV. Read More

An analysis of data on pbar-p -> eta-eta-pizero-pizero is presented at pbar beam momenta 600 to 1940 MeV/c. There is evidence for an I = 1, J^PC = 2^-+ resonance in eta-eta-pizero with mass M = 1880 +- 20 MeV and width 255 +- 45 MeV, decaying strongly a2(1320)-eta; it is too strong to be explained as the high mass tail of \pi_2(1670) -> a2(1320)-eta. There is tentative evidence also for weak decays to f_0(1500)\pi. Read More

New Crystal Barrel data are reported for pbar-p -> omega-eta and pbar-p -> omega-pizero-pizero with omega decaying to piplus-piminus-pizero. The omega-eta data confirm angular distributions obtained earlier from data where omega -> pizero-gamma. The new omega-eta data provide accurate measurements of vector and tensor polarisations of the omega and lead to considerable improvements in masses and widths of s-channel resonances. Read More

New Crystal Barrel data are reported for pbar-p -> omega-pizero and pbar-p -> omega eta-pizero with omega decaying to piplus-piminus-pizero. The shapes of angular distributions agree well with those for data where omega -> pizero-gamma; this is a valuable cross-check on systematic errors. The new data provide good measurements of vector and tensor polarisations P_y, T20, T21 and T22 of the omega. Read More

We present data on pbar-p -> eta-eta-pizero at beam momenta of 600, 900, 1050, and 1200 MeV/c. At the higher three momenta, a signal is clearly visible due to pbar-p -> f_0(1770)-pizero, f_0(1770) -> eta-eta. It has mass 1770+-12 MeV and width 220+-40 MeV, where errors cover systematic uncertainties as well as statistics. Read More

Data on pbar-p -> 3eta for beam momenta 600--1940 MeV/c are presented. The strongest channel is f_0(1500)-eta from the initial pbar-p state 1S0. Together with eta-pizero-pizero data, the 3eta data determine the branching ratio BR[f_0(1500) -> eta-eta]/BR[f_0(1500) -> pizero-pizero] = 0. Read More

Data on pbar-p -> etaprime(958)-pizero-pizero are presented at nine pbar momenta from 600 to 1940 MeV/c. Strong S-wave production of f_2(1270)-etaprime is observed, requiring a J^{PC} = 2^{-+} resonance with mass M = 2248+-20 MeV, Gamma = 280+-20 MeV. Read More