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1. Photoproduction of ω mesons off the proton

Author

A. Wilson, V. Crede, A.V. Anisovich, J.C.S. Bacelar, B. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Y.A. Beloglazov, K.T. Brinkmann, R. Castelijns, H. Dutz, D. Elsner, R. Ewald, F. Frommberger, M. Fuchs, Chr. Funke, R. Gregor, A. Gridnev, E. Gutz, J. Hannappel, W. Hillert, P. Hoffmeister, I. Horn, I. Jaegle, T. Jude, J. Junkersfeld, H. Kalinowsky, V. Kleber, Frank Klein, Friedrich Klein, E. Klempt, M. Kotulla, B. Krusche, M. Lang, H. Löhner, I.V. Lopatin, S. Lugert, T. Mertens, J.G. Messchendorp, V. Metag, M. Nanova, V.A. Nikonov, D. Novinski, R. Novotny, M. Ostrick, L.M. Pant, H. van Pee, M. Pfeiffer, A. Roy, A.V. Sarantsev, C. Schmidt, H. Schmieden, S. Shende, V. Sokhoyan, N. Sparks, A. Süle, V.V. Sumachev, T. Szczepanek, U. Thoma, D. Trnka, R. Varma, D. Walther, Ch. Wendel, and U. Wiedner

Subjects
Meson production, Light mesons, Baryon resonances, Photoproduction reactions, Physics, QC1-999
Abstract

The differential cross sections and unpolarized spin-density matrix elements for the reaction γp→pω were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the ω meson, ω→π0γ. The cross sections cover the full angular range and show the full extent of the t-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn–Gatchina partial wave analysis (PWA). The dominant contribution to ω photoproduction near threshold was found to be the 3/2+ partial wave, which is primarily due to the sub-threshold N(1720)3/2+ resonance. At higher energies, pomeron-exchange was found to dominate whereas π-exchange remained small. These t-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the 1/2−, 3/2−, and 5/2+ partial waves were also found to contribute significantly.

Published
2015
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2. Data on Is and Ic in γ→p→pπ0π0 reveal cascade decays of N(1900) via N(1520)π

Author

V. Sokhoyan, E. Gutz, H. van Pee, A.V. Anisovich, J.C.S. Bacelar, B. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Y. Beloglazov, R. Castelijns, V. Crede, H. Dutz, D. Elsner, R. Ewald, F. Frommberger, M. Fuchs, Ch. Funke, R. Gregor, A. Gridnev, W. Hillert, Ph. Hoffmeister, I. Horn, I. Jaegle, J. Junkersfeld, H. Kalinowsky, S. Kammer, V. Kleber, Frank Klein, Friedrich Klein, E. Klempt, M. Kotulla, B. Krusche, M. Lang, H. Löhner, I. Lopatin, S. Lugert, T. Mertens, J.G. Messchendorp, V. Metag, M. Nanova, V.A. Nikonov, D. Novinski, R. Novotny, M. Ostrick, L. Pant, M. Pfeiffer, D. Piontek, A. Roy, A.V. Sarantsev, Ch. Schmidt, H. Schmieden, S. Shende, A. Süle, V.V. Sumachev, T. Szczepanek, A. Thiel, U. Thoma, D. Trnka, R. Varma, D. Walther, Ch. Wendel, and A. Wilson

Subjects
Physics, QC1-999
Abstract

Photoproduction of two neutral pions off the proton is studied using linearly polarized photons, and the polarization observables Is and Ic are measured for the first time. These two observables are unique to multi-meson final states; they characterize correlations between the linear photon polarization and the direction of outgoing single particles in photoproduction of three-body final states. The Is and Ic distributions suggest that, in the 1.8 to 2.0 GeV mass region, the N(1520)3/2−π intermediate state is reached with reaction dynamics consistent with a dominant JP=3/2+ wave. These data are included in the Bonn–Gatchina (BnGa) partial wave analysis which is based on a large variety of data; the analysis confirms a significant contribution from the reaction chain γp→N(1900)3/2+→N(1520)3/2−π0→pπ0π0. Keywords: Baryon spectroscopy, Double meson photoproduction, Polarization observables

Published
2015
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3. Measurement of polarisation observables in Ks0Σ+ photoproduction off the proton

Author

R. Ewald, A.V. Anisovich, B. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Y.A. Beloglazov, K.-T. Brinkmann, V. Crede, H. Dutz, D. Elsner, K. Fornet-Ponse, F. Frommberger, Ch. Funke, A.B. Gridnev, E. Gutz, J. Hannappel, W. Hillert, P. Hoffmeister, I. Jaegle, O. Jahn, T.C. Jude, J. Junkersfeld, H. Kalinowsky, S. Kammer, V. Kleber, Frank Klein, Friedrich Klein, E. Klempt, B. Krusche, M. Lang, H. Löhner, I.V. Lopatin, D. Menze, T. Mertens, J.G. Messchendorp, V. Metag, M. Nanova, V.A. Nikonov, D. Novinski, R. Novotny, M. Ostrick, L. Pant, H. van Pee, A. Roy, A.V. Sarantsev, S. Schadmand, C. Schmidt, H. Schmieden, B. Schoch, S. Shende, V. Sokhoyan, A. Süle, V.V. Sumachev, T. Szczepanek, U. Thoma, D. Trnka, R. Varma, D. Walther, and Ch. Wendel

Subjects
Physics, QC1-999
Abstract

The reaction γp→KS0Σ+ 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 Eγ=1650MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay Σ+→pπ0 up to Eγ=2250MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed prominent structure in the cross section near the K⁎ thresholds is discussed. Keywords: Meson production, Other strange mesons, Baryon resonances (SCB0), Decays of baryons, Polarisation in interactions and scattering

Published
2014
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4. Photoproduction of $ \eta{^\prime}$ -mesons off the deuteron

Author

S. Lugert, D. Walther, S. Hoeffgen, D. Trnka, I. Jaegle, M. Ostrick, Eberhard Klempt, A. V. Anisovich, Matthew Lang, U. Thoma, Kanzo Nakayama, T. Szczepanek, D. Menze, V. Metag, J. Junkersfeld, Fei Huang, V. Kleber, Wolfgang Hillert, V. Crede, H. Loehner, H. van Pee, Yu. A. Beloglazov, A. V. Sarantsev, T. Mertens, D. V. Novinski, S. Kammer, J. C. S. Bacelar, R. Gregor, R. Castelijns, V. A. Nikonov, M. Kotulla, C. Funke, L. Tiator, R. Ewald, O. Bartholomy, D. Elsner, Lalit Mohan Pant, R. Varma, Friedrich Klein, H. Dutz, Ch. Wendel, B. Krusche, Ch. Schmidt, R. W. Novotny, A. Suele, V. V. Sumachev, J. G. Messchendorp, S. Shende, B. Schoch, A. Fix, H. Kalinowsky, V. Sokhoyan, I. V. Lopatin, H. Schmieden, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, R. Beck, S. Schadmand, Ankhi Roy, E. Gutz, B. Bantes, Frank Frommberger, Frank Klein, and M. Pfeiffer

Subjects
Physics, Nuclear and High Energy Physics, Photon, Proton, Meson, Nuclear Theory, Particle accelerator, law.invention, Nuclear physics, Recoil, Deuterium, law, Neutron, High Energy Physics::Experiment, Nucleon, Nuclear Experiment
Abstract

Quasi-free photoproduction of $ \eta{^\prime}$ -mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam of the ELSA electron accelerator in Bonn for incident photon energies from the production threshold up to 2.5GeV. The $ \eta{^\prime}$ -mesons have been detected in coincidence with recoil protons and recoil neutrons. The quasi-free proton data are in good agreement with the results for free protons, indicating that nuclear effects have no significant impact. The coincidence with recoil neutrons provides the first data for the $ \gamma$ n $ \rightarrow$ n $ \eta{^\prime}$ reaction. In addition, also first estimates for coherent $ \eta{^\prime}$ -production off the deuteron have been obtained. In agreement with model predictions, the total cross-section for this channel is found to be very small, at most at the level of a few nb. The data are compared to model calculations taking into account contributions from nucleon resonances and t -channel exchanges

Published
2018

5. Photoproduction of η -mesons off nuclei for Eγ ⩽ 2.2 GeV

Author

Lalit Mohan Pant, B. Bantes, M. Pfeiffer, D. Menze, R. Ewald, S. Hoeffgen, Ankhi Roy, Ch. Wendel, V. V. Sumachev, H. Kalinowsky, Matthew Lang, A. Ehmanns, R. Varma, D. Elsner, I. Jaegle, S. Kammer, R. Castelijns, H. Dutz, S. Shende, V. Sokhoyan, S. Lugert, D. Trnka, B. Krusche, R. W. Novotny, Ph. Hoffmeister, K. Essig, J. Langheinrich, T. Szczepanek, A. Suele, O. Bartholomy, S. Schadmand, Ulrich Mosel, R. Gregor, Yu. A. Beloglazov, M. Konrad, R. W. Gothe, Eberhard Klempt, J. C. S. Bacelar, M. Kotulla, C.-H. Weinheimer, B. Schoch, C. Morales, M. Ostrick, I. Fabry, Michael Fuchs, R. Beck, E. Gutz, J. Lotz, V. Metag, V. Crede, Ch. Schmidt, Frank Klein, Friedrich Klein, V. Kleber, H. Schmieden, I. V. Lopatin, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, H. van Pee, D. V. Novinski, J. G. Messchendorp, K. Fornet-Ponse, D. Walther, C. Funke, I. Horn, A. Radkov, T. Mertens, U. Thoma, P. Muehlich, J. Junkersfeld, and H. Loehner

Subjects
Mass number, Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, Nuclear matter, Resonance (particle physics), Nuclear physics, Pion, Production (computer science), High Energy Physics::Experiment, Absorption (logic), Nucleon, Nuclear Experiment
Abstract

Photoproduction of $\eta$ mesons off $^{12}$C, $^{40}$Ca, $^{93}$Nb, and $^{nat}$Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2 GeV. The experiment was performed at the Bonn ELSA accelerator with the combined setup of the Crystal Barrel and TAPS calorimeters. It aimed at the in-medium properties of the S$_{11}$(1535) nucleon resonance and the study of the absorption properties of nuclear matter for $\eta$ mesons. Careful consideration was given to contributions from $\eta\pi$ final states and secondary production mechanisms of $\eta$-mesons e.g. from inelastic $\pi N$ reactions of intermediate pions. The analysis of the mass number scaling shows that the nuclear absorption cross section $\sigma_{N\eta}$ for $\eta$ mesons is constant over a wide range of the $\eta$ momentum. The comparison of the excitation functions to data off the deuteron and to calculations in the framework of a BUU-model show no unexplained in-medium modifications of the S$_{11}$(1535)., Comment: Accepted for publication in Eur. Phys. J. A

Published
2018

6. Data onIsandIcinγ→p→pπ0π0reveal cascade decays ofN(1900)viaN(1520)π

Author

H. Schmieden, D. E. Bayadilov, Mariana Nanova, M. Pfeiffer, Y. Beloglazov, H. Dutz, A. Suele, D. Walther, E. Gutz, D. Piontek, V. Crede, T. Szczepanek, J. C. S. Bacelar, A. V. Sarantsev, I. V. Lopatin, Matthew Lang, Frank Frommberger, Lalit Mohan Pant, M. Fuchs, V. Kleber, R. Gregor, Friedrich Klein, A. Gridnev, V. Metag, M. Kotulla, V. Sokhoyan, A. V. Anisovich, Ch. Schmidt, U. Thoma, A. Thiel, R. Ewald, M. Ostrick, S. Kammer, S. Lugert, J. G. Messchendorp, J. Junkersfeld, T. Mertens, Herbert Löhner, Eberhard Klempt, Ch. Funke, I. Jaegle, D. Trnka, R. Varma, B. Bantes, V. A. Nikonov, I. Horn, R. Beck, R. Castelijns, D. V. Novinski, B. Krusche, H. Kalinowsky, Ankhi Roy, Ch. Wendel, V. V. Sumachev, Wolfgang Hillert, D. Elsner, R. W. Novotny, Ph. Hoffmeister, O. Bartholomy, H. van Pee, S. Shende, Frank Klein, and A. Wilson

Subjects
Baryon, Physics, Nuclear physics, Nuclear and High Energy Physics, Pion, Photon, Linear polarization, Partial wave analysis, Photon polarization, Pi, Dalitz plot
Abstract

Photoproduction of two neutral pions off the proton is studied using linearly polarized photons, and the polarization observables I-s and I-c are measured for the first time. These two observables are unique to multi-meson final states; they characterize correlations between the linear photon polarization and the direction of outgoing single particles in photoproduction of three-body final states. The I-s and I-c distributions suggest that, in the 1.8 to 2.0 GeV mass region, the N(1520) 3/2(-)pi intermediate state is reached with reaction dynamics consistent with a dominant J(P) = 3/2(+) wave. These data are included in the Bonn-Gatchina (BnGa) partial wave analysis which is based on a large variety of data; the analysis confirms a significant contribution from the reaction chain gamma p -> N(1900)3/2(+) -> N(1520)3/2(-)pi(0) -> p pi(0)pi(0). (C) 2015 The Authors. Published by Elsevier B.V.

Published
2015

7. Measurement of polarisation observables inKs0Σ+photoproduction off the proton

Author

Volker Metag, H. Dutz, S. Schadmand, T. Mertens, T. C. Jude, Matthew Lang, H. Schmieden, R. Ewald, D. E. Bayadilov, K. Fornet-Ponse, A. B. Gridnev, Mariana Nanova, D. Walther, A. Suele, V. Sokhoyan, Friedrich Klein, J. G. Messchendorp, V. Kleber, T. Szczepanek, M. Ostrick, Herbert Löhner, A. Roy, I. Jaegle, K.-T. Brinkmann, I. V. Lopatin, Ch. Schmidt, R. Varma, V. Crede, E. Gutz, D. Trnka, O. Jahn, R. Beck, Wolfgang Hillert, Lalit Mohan Pant, B. Bantes, S. Kammer, Ch. Funke, D. Elsner, Yu. A. Beloglazov, A. V. Sarantsev, V. A. Nikonov, R. W. Novotny, A. V. Anisovich, Ph. Hoffmeister, B. Schoch, D. Menze, Eberhard Klempt, J. Hannappel, Ch. Wendel, V. V. Sumachev, U. Thoma, J. Junkersfeld, S. Shende, H. Kalinowsky, D. V. Novinski, H. van Pee, B. Krusche, O. Bartholomy, Frank Klein, and Frank Frommberger

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Photon, Proton, Partial wave analysis, Hyperon, Bremsstrahlung, Photon energy, Nuclear Experiment, Nucleon, 7. Clean energy, Sigma baryon
Abstract

The reaction γ p → K S 0 Σ + 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 γ = 1650 MeV . In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay Σ + → p π 0 up to E γ = 2250 MeV . The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed prominent structure in the cross section near the K ⁎ thresholds is discussed.

Published
2014

8. Anomaly in the KS0Σ+ photoproduction cross section off the proton at the K⁎ threshold

Author

Volker Metag, Wolfgang Hillert, S. Shende, A. Suele, D. Walther, S. Kammer, Ch. Funke, Frank Frommberger, J. Hannappel, H. van Pee, D. Elsner, B. Krusche, D. Menze, R. W. Novotny, Ph. Hoffmeister, O. Bartholomy, B. Schoch, H. Schmieden, U. Thoma, D. E. Bayadilov, A. B. Gridnev, E. Gutz, A. Roy, Mariana Nanova, T. Szczepanek, V. Sokhoyan, Eberhard Klempt, Yu. A. Beloglazov, Ch. Wendel, R. Beck, V. V. Sumachev, Frank Klein, J. Junkersfeld, K. T Brinkmann, H. Kalinowsky, Matthew Lang, S. Schadmand, M. Ostrick, V. Kleber, R. Varma, L. M. Pant, H. Dutz, V. Crede, T. Mertens, Herbert Löhner, R. Ewald, B. Bantes, D. V. Novinski, D. Trnka, Ch. Schmidt, O. Jahn, K. Fornet-Ponse, I. Jaegle, Friedrich Klein, I. V. Lopatin, T. C. Jude, and J. G. Messchendorp

Subjects
Physics, Nuclear physics, Baryon, Nuclear and High Energy Physics, Cross section (physics), Proton, Meson, Hadron, Elementary particle, Strangeness, Nucleon
Abstract

The γ + p → K 0 + Σ + photoproduction reaction is investigated in the energy region from threshold to E γ = 2250 MeV . The differential cross section exhibits increasing forward-peaking with energy, but only up to the K ⁎ threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the K ⁎ Λ and K ⁎ Σ thresholds.

Published
2012

9. Transparency ratio in γA→η′A′ and the in-medium η′ width

Author

B. Krusche, I. Horn, V. Metag, A. Radkov, S. Lugert, O. Bartholomy, D. Menze, Angels Ramos, Eberhard Klempt, S. Höffgen, K.-T. Brinkmann, T. Szczepanek, Ch. Wendel, I. Jaegle, A. Süle, V. V. Sumachev, J. Junkersfeld, K. Essig, C. Morales, M. Fuchs, H. Dutz, Frank Klein, Yu. A. Beloglazov, A. Ehmanns, E. Gutz, Ch. Funke, M. Konrad, Lalit Mohan Pant, M. Ostrick, H. Kalinowsky, M. Pfeiffer, Friedrich Klein, K. Makonyi, R. Ewald, I. V. Lopatin, T. Mertens, Herbert Löhner, H. van Pee, V. Crede, B. Kopf, D. Trnka, J. Langheinrich, J. G. Messchendorp, D. Elsner, U. Thoma, Ankhi Roy, R. W. Novotny, J. Lotz, D. Walther, Ph. Hoffmeister, B. Schoch, Ch. Schmidt, Eulogi Oset, H. Schmieden, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, I. Fabry, S. Schadmand, R. Gregor, and R. Varma

Subjects
Physics, Nuclear and High Energy Physics, Photon, Proton, Meson, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Niobium, chemistry.chemical_element, Rest frame, 7. Clean energy, 01 natural sciences, Momentum, Nuclear physics, Cross section (physics), chemistry, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The photoproduction of η ′ -mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500–2200 MeV. The transparency ratio has been deduced and compared to theoretical calculations describing the propagation of η ′ -mesons in nuclei. The comparison indicates a width of the η ′ -meson of the order of Γ = 15 – 25 MeV at ρ = ρ 0 for an average momentum p η ′ = 1050 MeV / c , at which the η ′ -meson is produced in the nuclear rest frame. The inelastic η ′ N cross section is estimated to be 3–10 mb. Parameterizing the photoproduction cross section of η ′ -mesons by σ ( A ) = σ 0 A α , a value of α = 0.84 ± 0.03 has been deduced.

Published
2012

10. Erratum to: High-statistics study of the reaction $\gamma p\rightarrow p2\pi^{0}$

Author

V. Metag, S. Lugert, Eberhard Klempt, T. Seifen, M. Kotulla, Alastair J. Wilson, Frank Klein, M. Ostrick, D. Walther, S. Kammer, Friedrich Klein, T. Mertens, H. Dutz, V. A. Nikonov, Ch. Funke, Herbert Löhner, J. G. Messchendorp, Lalit Mohan Pant, V. Crede, I. Horn, Frank Frommberger, S. Shende, A. Thiel, Ankhi Roy, Ch. Schmidt, V. Sokhoyan, R. Ewald, B. Krusche, H. Pee, O. Bartholomy, M. Pfeiffer, T. Szczepanek, E. Gutz, B. Bantes, H. Kalinowsky, Michael Fuchs, Yu. A. Beloglazov, D. Piontek, J. C. S. Bacelar, A. V. Sarantsev, B. Metsch, D. Trnka, I. V. Lopatin, Ch. Wendel, Matthew Lang, V. V. Sumachev, A. V. Anisovich, I. Jaegle, V. Kleber, R. Gregor, R. Varma, J. Junkersfeld, D. Elsner, R. W. Novotny, Ph. Hoffmeister, U. Thoma, R. Castelijns, H. Schmieden, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, A. Süle, Wolfgang Hillert, D. Novinsky, and R. Beck

Subjects
Physics, Baryon, Nuclear and High Energy Physics, Meson, Isospin, Partial wave analysis, Bremsstrahlung, Dalitz plot, Photon energy, Atomic physics, Nucleon
Abstract

The photoproduction of 2π$^{0}$ mesons off protons was studied with the Crystal Barrel/TAPS experiment at the electron accelerator ELSA in Bonn. The energy of photons produced in a radiator was tagged in the energy range from 600 MeV to 2.5 GeV. Differential and total cross sections and pπ$^{0}$ π$^{0}$ Dalitz plots are presented. Part of the data was taken with a diamond radiator producing linearly polarized photons, and beam asymmetries were derived. Properties of nucleon and Δ resonances contributing to the pπ$^{0}$ π$^{0}$ final state were determined within the Bonn-Gatchina (BnGa) partial-wave analysis. The data presented here allow us to determine branching ratios of nucleon and Δ resonances for their decays into pπ$^{0}$ π$^{0}$ via several intermediate states. Most prominent are decays proceeding via Δ(1232)π, N(1440)1/2$^{+}$ π, N(1520)3/2$^{−}$ π, N(1680)5/2$^{+}$ π, but also pf$_{0}$(500), pf$_{0}$(980), and pf$_{2}$(1270) contribute to the reaction.

Published
2015

11. Photoproduction of meson pairs: First measurement of the polarization observable Is

Author

Matthew Lang, T. Mertens, Herbert Löhner, A. Suele, Michael Fuchs, V. Crede, D. Piontek, D. Walther, M. Pfeiffer, I. V. Lopatin, A. Thiel, V. Metag, Ch. Schmidt, H. Dutz, V. Sokhoyan, J. G. Messchendorp, M. Kotulla, J. C. S. Bacelar, Friedrich Klein, R. Beck, I. Jaegle, Winston Roberts, M. Ostrick, R. Gregor, R. Ewald, R. Castelijns, S. Schadmand, Ch. Weinheimer, H. Schmieden, R. Varma, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, D. Trnka, D. Elsner, T. Szczepanek, V. Kleber, R. W. Novotny, Ph. Hoffmeister, S. Kammer, B. Schoch, Ch. Funke, Lalit Mohan Pant, S. Lugert, Wolfgang Hillert, Eberhard Klempt, Ankhi Roy, V. A. Nikonov, D. Menze, I. Horn, A. V. Anisovich, Ch. Wendel, B. Bantes, V. V. Sumachev, Yu. A. Beloglazov, A. V. Sarantsev, H. Kalinowsky, B. Krusche, E. Gutz, D. V. Novinski, S. Shende, U. Thoma, H. van Pee, O. Bartholomy, J. Junkersfeld, Frank Frommberger, and Frank Klein

Subjects
Physics, Nuclear and High Energy Physics, Photon, Meson, Proton, Linear polarization, media_common.quotation_subject, Partial wave analysis, FOS: Physical sciences, Observable, Polarization (waves), Asymmetry, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, media_common
Abstract

The polarization observable I^s, a feature exclusive to the acoplanar kinematics of multi-meson final states produced via linearly polarized photons, has been measured for the first time. Results for the reaction g p -> p pi0 eta are presented for incoming photon energies between 970 MeV and 1650 MeV along with the beam asymmetry I^c. The comparably large asymmetries demonstrate a high sensitivity of I^s to the dynamics of the reaction. Fits using Bonn-Gatchina partial wave analysis demonstrate that the new polarization observables carry significant information on the contributing partial waves., 11 pages, 6 figures, v2 to appear in Phys. Lett. B

Published
2010

12. High-statistics study of the reaction γp → p2π0

Author

S. Kammer, Ch. Funke, M. Kotulla, V. Crede, T. Szczepanek, E. Gutz, Alastair J. Wilson, H. Schmieden, Yu. A. Beloglazov, J. C. S. Bacelar, A. V. Sarantsev, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, Frank Frommberger, V. Sokhoyan, V. Metag, H. Kalinowsky, H. Dutz, A. V. Anisovich, J. G. Messchendorp, U. Thoma, O. Bartholomy, Friedrich Klein, V. A. Nikonov, M. Pfeiffer, Lalit Mohan Pant, M. Ostrick, J. Junkersfeld, T. Seifen, I. Horn, S. Lugert, Ch. Schmidt, Ch. Wendel, V. V. Sumachev, Eberhard Klempt, T. Mertens, Frank Klein, Herbert Löhner, Michael Fuchs, A. Thiel, D. Piontek, B. Metsch, Ankhi Roy, I. V. Lopatin, H. van Pee, B. Krusche, S. Shende, B. Bantes, Wolfgang Hillert, D. Elsner, R. W. Novotny, Ph. Hoffmeister, I. Jaegle, D. Walther, R. Ewald, R. Varma, V. Kleber, Matthew Lang, R. Gregor, D. Novinsky, R. Beck, D. Trnka, R. Castelijns, and A. Süle

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Range (particle radiation), Photon, Meson, law, Linear polarization, Partial wave analysis, Particle accelerator, Nucleon, Beam (structure), law.invention
Abstract

The photoproduction of 2$\pi^0$ mesons off protons was studied with the Crystal Barrel/TAPS experiment at the electron accelerator ELSA in Bonn. The energy of photons produced in a radiator was tagged in the energy range from 600\,MeV to 2.5\,GeV. Differential and total cross sections and $p\pi^0\pi^0$ Dalitz plots are presented. Part of the data was taken with a diamond radiator producing linearly polarized photons, and beam asymmetries were derived. Properties of nucleon and $\Delta$ resonances contributing to the $p\pi^0\pi^0$ final state were determined within the BnGa partial wave analysis. The data presented here allow us to determine branching ratios of nucleon and $\Delta$ resonances for their decays into $p\pi^0\pi^0$ via several intermediate states. Most prominent are decays proceeding via $\Delta(1232)\pi$, $N(1440)1/2^+\pi$, $N(1520)3/2^-\pi$, $N(1680)5/2^+\pi$, but also $pf_0(500)$, $pf_0(980)$, and $pf_2(1270)$ contribute to the reaction.

Published
2015

13. Erratum: Modification of theω-Meson Lifetime in Nuclear Matter [Phys. Rev. Lett.100, 192302 (2008)]

Author

M. Kotulla, A. Ehmanns, I. Jaegle, Ulrich Mosel, Gisela Anton, V. Metag, V. Crede, S. Hoeffgen, I. Fabry, R. W. Gothe, Yu. A. Beloglazov, T. Mertens, J. C. S. Bacelar, M. Konrad, S. Shende, J. G. Messchendorp, D. E. Bayadilov, E. Gutz, H. Dutz, J. Lotz, A. B. Gridnev, Mariana Nanova, J. Hoessl, O. Bartholomy, Michael Fuchs, D. Trnka, J. Langheinrich, R. Gregor, I. V. Lopatin, D. Elsner, R. W. Novotny, Ph. Hoffmeister, R. Castelijns, R. Ewald, K. Essig, S. Schadmand, S. Lugert, Eberhard Klempt, P. Muehlich, J. Junkersfeld, H. Loehner, Fritz Klein, I. Horn, D. Menze, B. Kopf, Ch. Funke, B. Krusche, H. Kalinowsky, R. Bogendoerfer, and Frank Klein

Subjects
Nuclear physics, Physics, Particle physics, Meson production, Meson, General Physics and Astronomy, Nuclear matter, Omega
Published
2015

14. Three-Body Nature ofN*andΔ*Resonances from Sequential Decay Chains

Author

Frank Klein, V. Sokhoyan, A. Wilson, E. Gutz, M. Pfeiffer, S. Shende, J. Junkersfeld, J. G. Messchendorp, R. Beck, D. V. Novinski, Ch. Schmidt, M. Kotulla, D. Walther, V. A. Nikonov, R. Castelijns, Matthew Lang, Wolfgang Hillert, A. Thiel, A. V. Anisovich, I. Horn, S. Lugert, H. Kalinowsky, Cbelsa, U. Thoma, Eberhard Klempt, B. Bantes, V. Kleber, D. Elsner, Volker Metag, H. van Pee, R. Gregor, R. Varma, T. Mertens, Friedrich Klein, Herbert Löhner, R. W. Novotny, Yu. A. Beloglazov, B. Krusche, A. Roy, A. V. Sarantsev, Ph. Hoffmeister, O. Bartholomy, L. M. Pant, H. Dutz, S. Kammer, Bernard Metsch, Frank Frommberger, D. Piontek, Ch. Wendel, Ch. Funke, I. V. Lopatin, V. V. Sumachev, H. Schmieden, V. Crede, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, A. Süle, I. Jaegle, M. Ostrick, D. Trnka, J. C. S. Bacelar, R. Ewald, T. Szczepanek, and M. Fuchs

Subjects
Physics, Partial wave analysis, Nuclear Theory, General Physics and Astronomy, Dalitz plot, Delta baryon, Particle decay, Pion, Isobar, High Energy Physics::Experiment, Decay chain, Atomic physics, Nuclear Experiment, Nucleon
Abstract

The N pi(0)pi(0) decays of positive-parity N* and Delta* resonances at about 2 GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: Delta(1232), N(1520)3/2(-), and N(1680)5/2(+), with spin parities J(P) = 3/2(+), 3/2(-), and 5/2(+). The partial wave analysis (within the Bonn-Gatchina approach) identifies N(1440)1/2(+) and the N(pi pi)s (wave) (abbreviated as N sigma here) as further isobars and assigns the final states to the formation of nucleon and Delta resonances and to nonresonant contributions. We observe the know Delta(1232)pi decays of Delta(1910)1/2(+), Delta(1920)3/2(+), Delta(1905)5/2(+), Delta(1950)7/2(+), and of the corresponding spin-parity series in the nucleon sector, N(1880)1/2(+), N(1900)3/2(+), N(2000)5/2(+), and N(1990)7/2(+). For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via N(1440)1/2(pi)(+), N(1520)3/2(pi)(-) , N(1680)5/2(pi)(+), and N sigma. The latter decay modes are observed in the decay of N* resonances and at most weakly in Delta(*) decays. It is argued that these decay modes provide evidence for a 3-quark nature of N* resonances rather than a quark-diquark structure.

Published
2015

15. Photoproduction of omega mesons off protons and neutrons

Author

A. Süle, S. Höffgren, O. Bartholomy, M. Kotulla, Ankhi Roy, M. Konrad, Friedrich Klein, M. Ostrick, S. Schadmand, Matthew Lang, H. Dutz, M. Pfeiffer, J. C. S. Bacelar, V. Kleber, S. Shende, J. Junkersfeld, H. Schmieden, D. E. Bayadilov, V. Crede, H. Kalinowsky, R. Ewald, A. B. Gridnev, Mariana Nanova, I. Jaegle, A. V. Anisovich, Ch. Schmidt, T. Szczepanek, D. Menze, H. van Pee, S. Kammer, Frank Klein, R. Varma, F. Dietz, A. Wilson, I. V. Lopatin, T. Mertens, Herbert Löhner, U. Thoma, V. Shklyar, Ch. Wendel, Lalit Mohan Pant, Frank Frommberger, C. Funke, R. Beck, D. Walter, V. V. Sumachev, J. G. Messchendorp, R. W. Gothe, R. Castelijns, R. Gregor, D. Trnka, E. Gutz, V. Metag, B. Bantes, T. Rostomyan, V. A. Nikonov, I. Horn, S. Lugert, Eberhard Klempt, Y. A. Belogazov, D. Elsner, R. W. Novotny, Ph. Hoffmeister, B. Schoch, Wolfgang Hillert, B. Krusche, D. V. Novinski, and Research unit Nuclear & Hadron Physics

Subjects
Nuclear reaction, Physics, TAPS, Nuclear and High Energy Physics, Proton, Meson, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Nuclear Theory, WIDTH, Photon energy, DEUTERON, Nuclear physics, Deuterium, NUCLEAR MEDIUM, Neutron, High Energy Physics::Experiment, PHI-PHOTOPRODUCTION, SPECTROMETER, Atomic physics, Nucleon, Nuclear Experiment, MATTER
Abstract

Omega photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The omega meson has been identified via the omega -> pi(0) gamma -> gamma gamma gamma decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for omega mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of a parts per thousand 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV

Published
2015

16. In-Medium ω Photoproduction with CBELSA/TAPS

Author

D. Trnka

Subjects
Nuclear physics, Crystal, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Hadron, Detector, Barrel (horology), General Physics and Astronomy
Abstract

Recent experimental results on the in-medium modification of the ω meson are discussed. The experiment described was performed at the ELSA accelerator facility in Bonn using the combined detector system of Crystal Barrel and TAPS. The ω meson was identified via the reaction γ+A→ω+X→π0γ+X.

Published
2006

17. Three-body nature of N(*) and Δ(*) resonances from sequential decay chains

Author

A, Thiel, V, Sokhoyan, E, Gutz, H, van Pee, A V, Anisovich, J C S, Bacelar, B, Bantes, O, Bartholomy, D, Bayadilov, R, Beck, Yu, Beloglazov, R, Castelijns, V, Crede, H, Dutz, D, Elsner, R, Ewald, F, Frommberger, M, Fuchs, Ch, Funke, R, Gregor, A, Gridnev, W, Hillert, Ph, Hoffmeister, I, Horn, I, Jaegle, J, Junkersfeld, H, Kalinowsky, S, Kammer, V, Kleber, Frank, Klein, Friedrich, Klein, E, Klempt, M, Kotulla, B, Krusche, M, Lang, H, Löhner, I, Lopatin, S, Lugert, T, Mertens, J G, Messchendorp, V, Metag, B, Metsch, M, Nanova, V, Nikonov, D, Novinski, R, Novotny, M, Ostrick, L, Pant, M, Pfeiffer, D, Piontek, A, Roy, A V, Sarantsev, Ch, Schmidt, H, Schmieden, S, Shende, A, Süle, V V, Sumachev, T, Szczepanek, U, Thoma, D, Trnka, R, Varma, D, Walther, Ch, Wendel, and A, Wilson

Abstract

The Nπ^{0}π^{0} decays of positive-parity N^{*} and Δ^{*} resonances at about 2 GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: Δ(1232), N(1520)3/2^{-}, and N(1680)5/2^{+}, with spin parities J^{P}=3/2^{+}, 3/2^{-}, and 5/2^{+}. The partial wave analysis (within the Bonn-Gatchina approach) identifies N(1440)1/2^{+} and the N(ππ)_{S wave} (abbreviated as Nσ here) as further isobars and assigns the final states to the formation of nucleon and Δ resonances and to nonresonant contributions. We observe the known Δ(1232)π decays of Δ(1910)1/2^{+}, Δ(1920)3/2^{+}, Δ(1905)5/2^{+}, Δ(1950)7/2^{+}, and of the corresponding spin-parity series in the nucleon sector, N(1880)1/2^{+}, N(1900)3/2^{+}, N(2000)5/2^{+}, and N(1990)7/2^{+}. For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via N(1440)1/2^{+}π, N(1520)3/2^{-}π, N(1680)5/2^{+}π, and Nσ. The latter decay modes are observed in the decay of N^{*} resonances and at most weakly in Δ^{*} decays. It is argued that these decay modes provide evidence for a 3-quark nature of N^{*} resonances rather than a quark-diquark structure.

Published
2014

18. High statistics study of the reaction γp → pπ0 η

Author

E. Gutz, A. Süle, B. Bantes, S. Lugert, D. Elsner, R. Castelijns, R. W. Novotny, H. Schmieden, Ph. Hoffmeister, Eberhard Klempt, Frank Klein, B. Krusche, D. E. Bayadilov, A. B. Gridnev, O. Bartholomy, R. Gregor, M. Kotulla, Yu. A. Beloglazov, A. Wilson, J. C. S. Bacelar, A. V. Sarantsev, M. Ostrick, D. Trnka, Matthew Lang, T. Szczepanek, Ankhi Roy, A. V. Anisovich, Lalit Mohan Pant, Frank Frommberger, R. Varma, U. Thoma, M. Fuchs, V. Crede, D. Novinsky, V. Sokhoyan, J. Junkersfeld, V. Kleber, R. Beck, H. Dutz, Wolfgang Hillert, V. A. Nikonov, S. Shende, M. Pfeiffer, Ch. Wendel, S. Kammer, V. V. Sumachev, Ch. Funke, M. Nanova, I. Jaegle, R. Ewald, A. Thiel, I. Horn, H. van Pee, H. Kalinowsky, D. Walther, T. Mertens, Herbert Löhner, V. Metag, J. G. Messchendorp, D. Piontek, Ch. Schmidt, I. V. Lopatin, and Friedrich Klein

Subjects
Physics, Nuclear and High Energy Physics, Photon, Meson, 010308 nuclear & particles physics, Partial wave analysis, Nuclear Theory, Hadron, Dalitz plot, Electron, 01 natural sciences, Nuclear physics, 0103 physical sciences, Isobar, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Photoproduction off protons of the pπ 0 η three-body final state was studied with the Crystal Barrel/TAPS detector, at the electron stretcher accelerator ELSA in Bonn, for incident energies from the π 0 η production threshold up to 2.5 GeV. Differential cross sections and the total cross sections are presented. The use of linearly polarized photons gives access to the polarization observables Σ, I s , and I c , the latter two characterize beam asymmetries in case of three-body final states. Δ(1232)η, N(1535)1/2− π, and pa 0(980) are the dominant isobars contributing to the reaction. The partial wave analysis confirms the existence of some nucleon and Δ resonances, for which so far only fair evidence was reported. A large number of decay modes of known nucleon and Δ resonances is presented. It is shown that detailed investigations of decay branching ratios may provide a key to unravelling the structure of nucleon and Δ resonances.

Published
2014

19. Measurement of the beam asymmetry Σ in πeta; production off the proton with the CBELSA/TAPS experiment⋆

Author

C. Morales, S. Schadmand, D. Novinsky, R. Beck, A. Ehmanns, M. Konrad, K. Essig, Frank Klein, A. Süle, T. Szczepanek, J. Junkersfeld, Lalit Mohan Pant, S.V. Shende, V. Sokhoyan, M. Fuchs, I. V. Lopatin, V. V. Sumachev, Yu. A. Beloglazov, M. Ostrick, H. Schmieden, Ch. Wendel, V. Metag, Friedrich Klein, D. E. Bayadilov, A. V. Sarantsev, A. B. Gridnev, M. Kotulla, R. Castelijns, I. Jägle, U. Thoma, M. Pfeiffer, Matthew Lang, O. Bartholomy, A. Radkov, R. Novotny, H. Dutz, V. Crede, M. Nanova, H. Kalinowsky, D. Menze, V. Kleber, K. Fornet-Ponse, R. Gregor, J. Langheinrich, J. C. S. Bacelar, S. Lugert, D. Walther, I. Fabry, A. V. Anisovich, Ch. Schmidt, J. Lotz, J. G. Messchendorp, D. Trnka, S. Kammer, R. Ewald, Ch. Funke, H. van Pee, I. Horn, Ch. Weinheimer, R. W. Gothe, T. Mertens, Herbert Löhner, B. Krusche, E. Gutz, B. Bantes, V. A. Nikonov, D. Elsner, Ph. Hoffmeister, Eberhard Klempt, B. Schoch, and S. Höffgen

Subjects
Physics, Nuclear and High Energy Physics, Photon, Proton, media_common.quotation_subject, Bremsstrahlung, Particle accelerator, Asymmetry, Resonance (particle physics), law.invention, Nuclear physics, Pair production, law, Atomic physics, Nuclear Experiment, Beam (structure), media_common
Abstract

In photoproduction experiments, a large number of final states yielding various resonance contributions are accessible. To extract resonance parameters via partial-wave analysis not only the measurement of differential cross-sections is necessary, but also the determination of polarization observables. At the electron accelerator ELSA (Bonn) the coherent bremsstrahlung method was used to generate a linearly polarized photon beam. Using the CBELSA/TAPS detector setup, the beam asymmetry Σ in the reaction γp → pπ 0 η was determined as a function of various masses and angles for photon energies between 970MeV and 1650MeV.

Published
2008

20. Quasi-free photoproduction of eta-mesons off the deuteron

Author

D. Walther, U. Thoma, V. Crede, F. Frommberger, D. V. Novinski, S. Schadmand, V. Sokhoyan, V. Metag, S. Lugert, S. Kammer, B. Krusche, L. M. Pant, Yu. A. Beloglazov, Wolfgang Hillert, Eberhard Klempt, J. C. S. Bacelar, R. Castelijns, R. W. Gothe, S. Höffgen, Lilian Witthauer, R. Ewald, Ch. Funke, D. Elsner, O. Bartholomy, R. W. Novotny, Ph. Hoffmeister, H. Kalinowsky, R. Gregor, A. V. Anisovich, Frank Klein, J. Junkersfeld, B. Schoch, E. Gutz, M. Dieterle, T. Mertens, D. Menze, Herbert Löhner, A. V. Sarantsev, H. Schmieden, M. Pfeiffer, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, A. Roy, D. Trnka, H. van Pee, Ch. Wendel, Friedrich Klein, T. Szczepanek, V. V. Sumachev, V. A. Nikonov, R. Beck, I. Horn, M. Kotulla, B. Bantes, M. Konrad, Matthew Lang, V. Kleber, I. Jaegle, F. Pheron, S. V. Shende, Yasser Maghrbi, H. Dutz, D. Werthmüller, I. Keshelashvili, I. V. Lopatin, J. G. Messchendorp, R. Varma, M. Oberle, A. Süle, Ch. Schmidt, M. Ostrick, KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Proton, Meson, Hadron, Nuclear Theory, NUCLEON RESONANCE, FOS: Physical sciences, Photon energy, PROTON, ELSA, REGION, Nuclear physics, Effective mass (solid-state physics), Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, Physics, NEAR-THRESHOLD PHOTOPRODUCTION, CHIRAL DYNAMICS, EXCLUSIVE MEASUREMENT, POLARIZED PHOTON BEAMS, BARYON RESONANCES, ASYMMETRY, High Energy Physics::Experiment, Nucleon
Abstract

Precise data for quasi-free photoproduction of $\eta$ mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5 GeV. The $\eta$-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to $\eta$-production off the free proton. No significant effects beyond the folding of the free cross section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the $\eta$-nucleon pairs reconstructed from the final state four-momenta of the particles. The total cross section for quasi-free $\eta$-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1 GeV of incident photon energy, which is not observed for the proton. This structure is even narrower in the invariant mass spectrum of the $\eta$-neutron pairs. Position and width of the peak in the invariant mass spectrum are $W\approx 1665$ MeV and FWHM $\Gamma\approx 25$ MeV. The data are compared to the results of different models., Comment: accepted for publication in Eur. Phys. J. A

Published
2011

21. Photoproduction of Neutral Pions off Protons

Author

T. Mertens, Herbert Löhner, E. Gutz, V. A. Nikonov, H. Schmieden, Wolfgang Hillert, M. Ostrick, S. Schadmand, Frank Klein, D. E. Bayadilov, Yu. A. Beloglazov, H. Kalinowsky, A. V. Sarantsev, J. C. S. Bacelar, A. Wilson, A. B. Gridnev, D. V. Novinski, H. van Pee, R. Bantes, Mariana Nanova, V. Crede, N. Sparks, V. Sokhoyan, H. Dutz, A. Suele, D. Elsner, Ch. Schmidt, I. Jaegle, Frank Frommberger, R. Varma, R. Castelijns, R. W. Novotny, Ph. Hoffmeister, D. Menze, B. Krusche, R. Gregor, A. V. Anisovich, Friedrich Klein, Volker Metag, S. Shende, S. Kammer, B. Schoch, Ch. Wendel, C. Funke, V. V. Sumachev, M. Pfeiffer, O. Bartholomy, D. Walther, S. Lugert, L. M. Pant, M. Kotulla, Johannes Messchendorp, U. Thoma, Eberhard Klempt, J. Junkersfeld, A. Roy, I. V. Lopatin, R. Beck, R. Ewald, D. Trnka, T. Szczepanek, KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
Nuclear and High Energy Physics, Particle physics, N(2190), Photon, tagged beam [photon], Meson, 0.85-2.50 GeV, Partial wave analysis, electromagnetic [calorimeter], NUCLEON RESONANCE, FOS: Physical sciences, photoproduction [pi0], +p+pi0%22">photon p --> p pi0, Gamma gamma, REGION, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, High Energy Physics - Phenomenology (hep-ph), Pi, Bonn ELSA Stor, ddc:530, SPECTROMETER, NEAR-THRESHOLD, Nuclear Experiment (nucl-ex), Nuclear Experiment, AMPLITUDES, BARYON, Physics, N(2080), partial wave analysis, OPERATOR EXPANSION METHOD, Baryon, High Energy Physics - Phenomenology, Amplitude, exclusive reaction [photon p], angular dependence [differential cross section], STATES, High Energy Physics::Experiment, CROSS-SECTION, DECAY, small-angle, N(2070), experimental results, +2photon%22">pi0 --> 2photon
Abstract

Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction $\gamma p\to p\pi^0$ for photon energies between 0.85 and 2.50 GeV. The $\pi^0$ mesons are observed in their dominant neutral decay mode: $\pi^0\to\gamma\gamma$. For the first time, the differential cross sections cover the very forward region, $\theta_{\rm c.m.}, Comment: 12 pages, 9 figures, minor modifications to PWA section

Published
2011

22. In-mediumωmass from theγ+Nb→π0γ+Xreaction

Author

V. Metag, M. Ostrick, M. Kotulla, Ch. Schmidt, A. Ehmanns, V. Crede, M. Pfeiffer, D. Elsner, R. Ewald, R. Bogendorfer, R. W. Novotny, Ph. Hoffmeister, Yu. A. Beloglazov, R. Gregor, T. Szczepanek, Friedrich Klein, B. Schoch, J. C. S. Bacelar, H. Schmieden, D. E. Bayadilov, I. Fabry, A. Radkov, A. B. Gridnev, Mariana Nanova, G. Suft, S. Shende, Michael Fuchs, D. Trnka, J. Langheinrich, J. Lotz, O. Bartholomy, H. Dutz, U. Thoma, Frank Klein, J. Hossl, S. Schadmand, R. Varma, I. V. Lopatin, R. W. Gothe, D. Walther, Ch. Weinheimer, H. van Pee, E. Gutz, J. Junkersfeld, J. G. Messchendorp, T. Mertens, Herbert Löhner, C. Morales, Lalit Mohan Pant, M. Konrad, B. Kopf, I. Jaegle, Gisela Anton, Ch. Funke, I. Horn, S. Lugert, Eberhard Klempt, S. Höffgen, B. Krusche, R. Castelijns, K. Essig, A. Süle, Ankhi Roy, D. Menze, Ch. Wendel, V. V. Sumachev, and H. Kalinowsky

Subjects
Absolute magnitude, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, Electron, Sensitivity (control systems), Nuclear Experiment, Nuclear matter, Omega, Line (formation)
Abstract

Data on the photoproduction of $\ensuremath{\omega}$ mesons on nuclei have been reanalyzed in a search for in-medium modifications. The data were taken with the crystal barrel (CB)/two-arm photon spectrometer (TAPS) detector system at the ELectron Stretcher Anlage (ELSA) accelerator facility in Bonn. First results from the analysis of the data set were published by Trnka et al. [Phys. Rev. Lett. 94, 192303 (2005)], claiming a lowering of the $\ensuremath{\omega}$ mass in the nuclear medium by 14$%$ at normal nuclear matter density. The extracted $\ensuremath{\omega}$ line shape was found to be sensitive to the background subtraction. For this reason a reanalysis of the same data set has been initiated, and a new method has been developed to reduce the background and to determine the shape and absolute magnitude of the background directly from the data. Details of the reanalysis and of the background determination are described. The $\ensuremath{\omega}$ signal on the Nb target, extracted in the reanalysis, does not show a deviation from the corresponding line shape on a ${\mathrm{LH}}_{2}$ target, measured as reference. The earlier claim of an in-medium mass shift is thus not confirmed. The sensitivity of the $\ensuremath{\omega}$ line shape to different in-medium modification scenarios is discussed.

Published
2010

23. Measurement of the beam asymmetryΣin the forward direction forγ⃗p→pπ0

Author

O. Bartholomy, V. A. Nikonov, S. Lugert, Eberhard Klempt, H. Schmieden, D. E. Bayadilov, T. Mertens, E. Gutz, A. B. Gridnev, Mariana Nanova, Herbert Löhner, D. Elsner, R. Castelijns, Yu. A. Beloglazov, H. van Pee, H. Kalinowsky, J. C. S. Bacelar, A. V. Sarantsev, N. Sparks, R. W. Novotny, Ph. Hoffmeister, B. Krusche, D. Menze, Friedrich Klein, S. Kammer, I. Jaegle, C. Funke, Ch. Schmidt, Ch. Wendel, B. Schoch, V. V. Sumachev, L. M. Pant, A. Roy, R. Bantes, S. Shende, D. V. Novinski, V. Sokhoyan, Volker Metag, R. Gregor, A. V. Anisovich, U. Thoma, J. G. Messchendorp, D. Walther, S. Schadmand, J. Junkersfeld, R. Ewald, I. V. Lopatin, Wolfgang Hillert, R. Beck, D. Trnka, M. Kotulla, T. Szczepanek, R. Varma, A. Süle, M. Ostrick, V. Crede, Frank Klein, A. Wilson, M. Pfeiffer, and Frank Frommberger

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, media_common.quotation_subject, Hadron, Sigma, Elementary particle, Asymmetry, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Lepton, media_common
Abstract

Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector for photon energies between 0.92 and 1.68 GeV at the electron stretcher accelerator ELSA. The beam asymmetry Sigma has been extracted for 115 degrees > theta(c.m.) > 155 degrees of the pi(0) meson and for theta(c.m.) > 60 degrees. The new beam-asymmetry data cover the very forward region, which extend previously published data for the same reaction by our collaboration and improve the world database for photon energies above 1.5 GeV. The angular dependence of Sigma shows overall good agreement with the SAID parametrization.

Published
2010

25. Photoproduction ofηandη'mesons off protons

Author

V. Crede, A. McVeigh, A. V. Anisovich, J. C. S. Bacelar, R. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Y. A. Beloglazov, R. Castelijns, A. Ehmanns, D. Elsner, K. Essig, R. Ewald, I. Fabry, M. Fuchs, Chr. Funke, R. Gothe, R. Gregor, A. Gridnev, E. Gutz, St. Höffgen, P. Hoffmeister, I. Horn, I. Jaegle, J. Junkersfeld, H. Kalinowsky, S. Kammer, Frank Klein, Friedrich Klein, E. Klempt, M. Konrad, M. Kotulla, B. Krusche, J. Langheinrich, H. Löhner, I. V. Lopatin, J. Lotz, S. Lugert, D. Menze, T. Mertens, J. G. Messchendorp, V. Metag, M. Nanova, V. A. Nikonov, D. Novinski, R. Novotny, M. Ostrick, L. M. Pant, H. van Pee, M. Pfeiffer, A. Roy, A. V. Sarantsev, S. Schadmand, C. Schmidt, H. Schmieden, B. Schoch, S. Shende, V. Sokhoyan, N. Sparks, A. Süle, V. V. Sumachev, T. Szczepanek, U. Thoma, D. Trnka, R. Varma, D. Walther, Ch. Weinheimer, Ch. Wendel, and A. Wilson

Subjects
Physics, Nuclear and High Energy Physics, Angular range, Particle physics, Photon, Meson, Proton, Nuclear Theory, Eta meson, Gamma gamma, Baryon, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Total and differential cross sections for eta and eta(')photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The eta mesons are detected in their two neutral decay modes, eta ->gamma gamma and eta -> 3 pi(0)-> 6 gamma, and for the first time, cover the full angular range in cos theta(c.m.) of the eta meson. These new eta photoproduction data are consistent with the earlier CB-ELSA results. The eta(') mesons are observed in their neutral decay to pi(0)pi(0)eta -> 6 gamma and also extend the coverage in angular range.

Published
2009

26. Beam asymmetries in near-thresholdωphotoproduction off the proton

Author

V. Sokhoyan, Matthew Lang, M. Pfeiffer, D. Walther, A. Ehmanns, J. Junkersfeld, R. Varma, Ch. Weinheimer, S. Shende, Friedrich Klein, M. Ostrick, H. Kalinowsky, H. Dutz, Frank Klein, A. Roy, R. Beck, D. Elsner, D. Menze, V. Metag, E. Gutz, V. Crede, Ph. Hoffmeister, H. Schmieden, I. Jaegle, D. E. Bayadilov, S. Kammer, A. B. Gridnev, H. van Pee, Mariana Nanova, Ch. Wendel, V. Kleber, Ch. Funke, Yu. A. Beloglazov, R. Castelijns, A. Suele, V. V. Sumachev, A. V. Sarantsev, O. Bartholomy, M. Kotulla, K. Essig, M. Konrad, D. Trnka, R. Novotny, S. Hoeffgen, I. V. Lopatin, T. Mertens, A. V. Anisovich, U. Thoma, Herbert Löhner, B. Bantes, C. Morales, B. Schoch, A. Radkov, J. G. Messchendorp, I. Fabry, J. C. S. Bacelar, R. Gregor, R. Ewald, T. Szczepanek, M. Fuchs, V. A. Nikonov, I. Horn, S. Lugert, Eberhard Klempt, Ch. Schmidt, J. Lotz, D. V. Novinski, B. Krusche, L. M. Pant, Research unit Nuclear & Hadron Physics, and Publica

Subjects
TAPS, Physics, Nuclear and High Energy Physics, Photon, Proton, Meson, media_common.quotation_subject, photon, Nuclear Theory, Bremsstrahlung, Resonance, PHOTONS, MESONS, ETA, Omega, Asymmetry, Nuclear physics, Pion, SPECTROMETER, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, media_common
Abstract

The photoproduction of {omega} mesons off protons has been studied at the Bonn ELSA accelerator from threshold to E{sub {gamma}}=1700 MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmetries in excess of 50% were obtained. For the first time the pion asymmetries associated with the {omega}{yields}{pi}{sup 0}{gamma} decay were measured and found close to zero. The asymmetries indicate s-channel resonance formation on top of t-channel exchange processes.

Published
2008

27. Quasifree photoproduction of eta mesons off the neutron

Author

T. Szczepanek, Ch. Weinheimer, B. Schoch, A.B. Gridnev, Herbert Löhner, C. Morales, A. Radkov, V. Metag, U. Thoma, M. Kotulla, D. V. Novinski, H. Dutz, T. Mertens, L.M. Pant, R. Varma, J. Junkersfeld, M. Ostrick, H. van Pee, V. A. Nikonov, R. Ewald, I. Fabry, M. Fuchs, D. Menze, A. Roy, O. Bartholomy, A. Ehmanns, M. Nanova, I. Horn, R. Beck, D. Elsner, J. Lotz, M. Konrad, B. Krusche, V. Sokhoyan, S. Schadmand, Frank Klein, D. Trnka, Eberhard Klempt, Ph. Hoffmeister, Ch. Funke, A. V. Sarantsev, S. Höffgen, R. Gregor, J. Langheinrich, J. C. S. Bacelar, Ch. Wendel, H. Schmieden, D. E. Bayadilov, S. Kammer, S. Lugert, B. Bantes, R. Novotny, K. Essig, M. Pfeiffer, Y.A. Beloglazov, A. Süle, H. Kalinowsky, A.V. Anisovich, R. W. Gothe, Ch. Schmidt, D. Walther, E. Gutz, V. V. Sumachev, Friedrich Klein, I. Jaegle, V. Kleber, S.V. Shende, R. Castelijns, M. Lang, J. G. Messchendorp, V. Crede, I. V. Lopatin, Publica, and KVI - Center for Advanced Radiation Technology

Subjects
Physics, Photon, Meson, Proton, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, NEAR-THRESHOLD PHOTOPRODUCTION, BEAM ASYMMETRY, General Physics and Astronomy, EXCLUSIVE MEASUREMENT, Photon energy, RESONANCE, PROTON, ELSA, DEUTERON, Nuclear physics, Recoil, Deuterium, S-11(1535), High Energy Physics::Experiment, Invariant mass, Neutron, SPECTROMETER, Nuclear Experiment, HE-4
Abstract

Precise data for quasi-free photoproduction of η-mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5GeV. The η-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to η-production off the free proton. No significant effects beyond the folding of the free cross-section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the η-nucleon pairs reconstructed from the final-state four-momenta of the particles. The total cross-section for quasi-free η-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1GeV of incident photon energy, which is not observed for the proton. This structure is even narrower in the invariant-mass spectrum of the η-neutron pairs. Position and width of the peak in the invariant-mass spectrum are W ≈ 1665 MeV and FWHM Γ ≈ 25 MeV. The data are compared to the results of different models.

Published
2008

28. Modification of the omega-meson lifetime in nuclear matter

Author

R. W. Novotny, Ph. Hoffmeister, B. Schoch, J. C. S. Bacelar, D. Menze, D. Elsner, R. Ewald, A. Radkov, T. Mertens, M. Kotulla, H. Dutz, B. Kopf, Ch. Wendel, A. Suele, V. V. Sumachev, D. Trnka, J. Langheinrich, I. Horn, T. Szczepanek, J. Hoessl, I. Jaegle, Gisela Anton, Fritz Klein, M. Ostrick, R. Castelijns, E. Gutz, Volker Metag, S. Lugert, S. Hoeffgen, R. W. Gothe, M. Fuchs, H. van Pee, Eberhard Klempt, K. Essig, Ch. Funke, J. Lotz, H. Kalinowsky, M. Konrad, V. Crede, B. Krusche, S. Shende, Frank Klein, Yu. A. Beloglazov, L. M. Pant, A. Ehmanns, Ch. Weinheimer, M. Pfeiffer, J. G. Messchendorp, O. Bartholomy, H. Schmieden, S. Schadmand, U. Mosel, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, Ch. Schmidt, I. V. Lopatin, G. Suft, R. Bogendoerfer, U. Thoma, D. Walther, P. Muehlich, R. Gregor, I. Fabry, J. Junkersfeld, A. Roy, H. Loehner, R. Varma, KVI - Center for Advanced Radiation Technology, and Publica

Subjects
TAPS, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Omega, Nuclear physics, ATTENUATION, QCD SUM-RULES, SPECTROMETER, Nuclear Experiment, Mass number, Physics, IN-MEDIUM, Nuclear matter, Omega baryon, Baryon, High Energy Physics - Phenomenology, PHOTON, High Energy Physics::Experiment, PHI-PHOTOPRODUCTION, Glauber, VECTOR-MESONS
Abstract

The photo production of $\omega$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $\omega$ meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic $\omega$ width is found to be $130-150 \rm{MeV/c^2}$ at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the $\omega$ meson, this inelastic $\omega$ width corresponds to a reduction of the $\omega$ lifetime by a factor $\approx 30$. For the first time, the momentum dependent $\omega$N cross section has been extracted from the experiment and is in the range of 70 mb., Comment: 5 pages, 4 figures

Published
2007

29. Observation of In-Medium Modifications of theωMeson

Author

V. Crede, V. Metag, I. Fabry, Yu. A. Beloglazov, Lalit Mohan Pant, R. W. Gothe, S. Lugert, H. Dutz, J. Hossl, Eberhard Klempt, S. Höffgen, R. Varma, R. Castelijns, Fritz Klein, I. Horn, M. Ostrick, G. Suft, S. Shende, I. Jaegle, M. Kotulla, T. Mertens, R. Gregor, S. Schadmand, Herbert Löhner, A. Roy, Gisela Anton, O. Bartholomy, Ch. Schmidt, C. Morales, J. Lotz, D. Trnka, J. Langheinrich, H. Kalinowsky, D. Walther, T. Szczepanek, Frank Klein, K. Essig, A. Süle, E. Gutz, B. Kopf, B. Krusche, A. Radkov, A. Ehmanns, H. van Pee, M. Pfeiffer, Ch. Funke, D. Menze, D. Elsner, M. Konrad, H. Schmieden, D. E. Bayadilov, Ch. Wendel, A. B. Gridnev, Mariana Nanova, V. V. Sumachev, U. Thoma, R. W. Novotny, Ph. Hoffmeister, J. C. S. Bacelar, B. Schoch, J. Junkersfeld, R. Ewald, R. Bogendorfer, J. G. Messchendorp, Michael Fuchs, I. V. Lopatin, and Ch. Weinheimer

Subjects
Physics, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Omega baryon, Omega, Baryon, Nuclear physics, Particle decay, Pion, High Energy Physics::Experiment, Nuclear Experiment, Nuclear density
Abstract

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma+A

Published
2005

30. Epidermal growth factor receptors in Rous sarcoma virus-transformed cells of different hosts

Author

V, Sovová, H, Fidlerová, D, Trnka, and E, Sloncová

Subjects
ErbB Receptors, Iodine Radioisotopes, Mice, Avian Sarcoma Viruses, Mesocricetus, Cricetinae, Tumor Cells, Cultured, Animals, Gene Expression, Humans, Receptors, Cell Surface, Blotting, Northern, Cell Transformation, Viral
Abstract

It was found that epidermal growth factor (EGF) binding on cells transformed by Rous sarcoma virus (RSV) differed in mice and hamsters. While EGF binding was considerably reduced in mouse tumours, the binding activity of hamster cells did not change after RSV transformation.

Published
1994

31. Molecular basis for the distinct functions of redox-active and FeS-transfering glutaredoxins.

Author

Trnka D, Engelke AD, Gellert M, Moseler A, Hossain MF, Lindenberg TT, Pedroletti L, Odermatt B, de Souza JV, Bronowska AK, Dick TP, Mühlenhoff U, Meyer AJ, Berndt C, and Lillig CH

Subjects
Animals, Catalytic Domain, Glutaredoxins chemistry, Humans, Iron-Sulfur Proteins chemistry, Oxidation-Reduction, Protein Binding, Protein Structure, Secondary, Signal Transduction physiology, Substrate Specificity, Glutaredoxins metabolism
Abstract

Despite their very close structural similarity, CxxC/S-type (class I) glutaredoxins (Grxs) act as oxidoreductases, while CGFS-type (class II) Grxs act as FeS cluster transferases. Here we show that the key determinant of Grx function is a distinct loop structure adjacent to the active site. Engineering of a CxxC/S-type Grx with a CGFS-type loop switched its function from oxidoreductase to FeS transferase. Engineering of a CGFS-type Grx with a CxxC/S-type loop abolished FeS transferase activity and activated the oxidative half reaction of the oxidoreductase. The reductive half-reaction, requiring the interaction with a second GSH molecule, was enabled by switching additional residues in the active site. We explain how subtle structural differences, mostly depending on the structure of one particular loop, act in concert to determine Grx function.

Published
2020
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32. Three-body nature of N(*) and Δ(*) resonances from sequential decay chains.

Author

Thiel A, Sokhoyan V, Gutz E, van Pee H, Anisovich AV, Bacelar JC, Bantes B, Bartholomy O, Bayadilov D, Beck R, Beloglazov Y, Castelijns R, Crede V, Dutz H, Elsner D, Ewald R, Frommberger F, Fuchs M, Funke Ch, Gregor R, Gridnev A, Hillert W, Hoffmeister P, Horn I, Jaegle I, Junkersfeld J, Kalinowsky H, Kammer S, Kleber V, Klein F, Klein F, Klempt E, Kotulla M, Krusche B, Lang M, Löhner H, Lopatin I, Lugert S, Mertens T, Messchendorp JG, Metag V, Metsch B, Nanova M, Nikonov V, Novinski D, Novotny R, Ostrick M, Pant L, Pfeiffer M, Piontek D, Roy A, Sarantsev AV, Schmidt Ch, Schmieden H, Shende S, Süle A, Sumachev VV, Szczepanek T, Thoma U, Trnka D, Varma R, Walther D, Wendel Ch, and Wilson A

Abstract

The Nπ^{0}π^{0} decays of positive-parity N^{*} and Δ^{*} resonances at about 2 GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: Δ(1232), N(1520)3/2^{-}, and N(1680)5/2^{+}, with spin parities J^{P}=3/2^{+}, 3/2^{-}, and 5/2^{+}. The partial wave analysis (within the Bonn-Gatchina approach) identifies N(1440)1/2^{+} and the N(ππ)_{S wave} (abbreviated as Nσ here) as further isobars and assigns the final states to the formation of nucleon and Δ resonances and to nonresonant contributions. We observe the known Δ(1232)π decays of Δ(1910)1/2^{+}, Δ(1920)3/2^{+}, Δ(1905)5/2^{+}, Δ(1950)7/2^{+}, and of the corresponding spin-parity series in the nucleon sector, N(1880)1/2^{+}, N(1900)3/2^{+}, N(2000)5/2^{+}, and N(1990)7/2^{+}. For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via N(1440)1/2^{+}π, N(1520)3/2^{-}π, N(1680)5/2^{+}π, and Nσ. The latter decay modes are observed in the decay of N^{*} resonances and at most weakly in Δ^{*} decays. It is argued that these decay modes provide evidence for a 3-quark nature of N^{*} resonances rather than a quark-diquark structure.

Published
2015
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33. Quasifree photoproduction of eta mesons off the neutron.

Author

Jaegle I, Mertens T, Anisovich AV, Bacelar JC, Bantes B, Bartholomy O, Bayadilov D, Beck R, Beloglazov YA, Castelijns R, Crede V, Dutz H, Ehmanns A, Elsner D, Essig K, Ewald R, Fabry I, Fuchs M, Funke Ch, Gothe R, Gregor R, Gridnev AB, Gutz E, Höffgen S, Hoffmeister P, Horn I, Junkersfeld J, Kalinowsky H, Kammer S, Kleber V, Klein F, Klein F, Klempt E, Konrad M, Kotulla M, Krusche B, Lang M, Langheinrich J, Löhner H, Lopatin IV, Lotz J, Lugert S, Menze D, Messchendorp JG, Metag V, Morales C, Nanova M, Nikonov VA, Novinski D, Novotny R, Ostrick M, Pant LM, van Pee H, Pfeiffer M, Radkov A, Roy A, Sarantsev AV, Schadmand S, Schmidt C, Schmieden H, Schoch B, Shende SV, Sokhoyan V, Süle A, Sumachev VV, Szczepanek T, Thoma U, Trnka D, Varma R, Walther D, Weinheimer Ch, and Wendel Ch

Abstract

Quasifree photoproduction of eta mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasifree n(gamma,eta)n and p(gamma,eta)p reactions. The excitation function for eta production off the neutron shows a pronounced bumplike structure at W=1.68 GeV (E{gamma} approximately 1 GeV), which is absent for the proton.

Published
2008
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34. Modification of the omega-meson lifetime in nuclear matter.

Author

Kotulla M, Trnka D, Mühlich P, Anton G, Bacelar JC, Bartholomy O, Bayadilov D, Beloglazov YA, Bogendörfer R, Castelijns R, Crede V, Dutz H, Ehmanns A, Elsner D, Ewald R, Fabry I, Fuchs M, Essig K, Funke Ch, Gothe R, Gregor R, Gridnev AB, Gutz E, Höffgen S, Hoffmeister P, Horn I, Hössl J, Jaegle I, Junkersfeld J, Kalinowsky H, Klein F, Klein F, Klempt E, Konrad M, Kopf B, Krusche B, Langheinrich J, Löhner H, Lopatin IV, Lotz J, Lugert S, Menze D, Messchendorp JG, Mertens T, Metag V, Mosel U, Nanova M, Novotny R, Ostrick M, Pant LM, van Pee H, Pfeiffer M, Roy A, Radkov A, Schadmand S, Schmidt Ch, Schmieden H, Schoch B, Shende S, Suft G, Sumachev VV, Szczepanek T, Süle A, Thoma U, Varma R, Walther D, Weinheimer Ch, and Wendel Ch

Abstract

Information on hadron properties in the nuclear medium has been derived from the photoproduction of omega mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the omega-meson cross section on the nuclear mass number has been compared with three different types of models: a Glauber analysis, a Boltzmann-Uehling-Uhlenbeck analysis of the Giessen theory group, and a calculation by the Valencia theory group. In all three cases, the inelastic omega width is found to be 130-150 MeV/c(2) at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the rest frame of the omega meson, this inelastic omega width corresponds to a reduction of the omega lifetime by a factor approximately 30. For the first time, the momentum dependent omegaN cross section has been extracted from the experiment and is in the range of 70 mb.

Published
2008
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35. Observation of in-medium modifications of the omega meson.

Author

Trnka D, Anton G, Bacelar JC, Bartholomy O, Bayadilov D, Beloglazov YA, Bogendörfer R, Castelijns R, Crede V, Dutz H, Ehmanns A, Elsner D, Ewald R, Fabry I, Fuchs M, Essig K, Funke Ch, Gothe R, Gregor R, Gridnev AB, Gutz E, Höffgen S, Hoffmeister P, Horn I, Hössl J, Jaegle I, Junkersfeld J, Kalinowsky H, Klein F, Klein F, Klempt E, Konrad M, Kopf B, Kotulla M, Krusche B, Langheinrich J, Löhner H, Lopatin IV, Lotz J, Lugert S, Menze D, Messchendorp JG, Mertens T, Metag V, Morales C, Nanova M, Novotny R, Ostrick M, Pant LM, van Pee H, Pfeiffer M, Roy A, Radkov A, Schadmand S, Schmidt Ch, Schmieden H, Schoch B, Shende S, Suft G, Sumachev VV, Szczepanek T, Süle A, Thoma U, Varma R, Walther D, Weinheimer Ch, and Wendel Ch

Abstract

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma + A --> omega + X --> pi(0)gamma + X('). Results obtained for Nb are compared to a reference measurement on a LH2 target. While for recoiling, long-lived mesons (pi(0), eta, and eta;(')), which decay outside of the nucleus, a difference in the line shape for the two data samples is not observed, we find a significant enhancement towards lower masses for omega mesons produced on the Nb target. For momenta less than 500 MeV/c an in-medium omega meson mass of M(medium) = [722(+4)(-4)(stat)+35-5(syst)] MeV/c(2) has been deduced at an estimated average nuclear density of 0.6rho(0).

Published
2005
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36. Epidermal growth factor receptors in Rous sarcoma virus-transformed cells of different hosts.

Author

Sovová V, Fidlerová H, Trnka D, and Sloncová E

Subjects
Animals, Avian Sarcoma Viruses metabolism, Blotting, Northern, Cricetinae, ErbB Receptors genetics, Gene Expression physiology, Humans, Iodine Radioisotopes, Mesocricetus, Mice, Receptors, Cell Surface, Tumor Cells, Cultured, Avian Sarcoma Viruses physiology, Cell Transformation, Viral, ErbB Receptors metabolism
Abstract

It was found that epidermal growth factor (EGF) binding on cells transformed by Rous sarcoma virus (RSV) differed in mice and hamsters. While EGF binding was considerably reduced in mouse tumours, the binding activity of hamster cells did not change after RSV transformation.

Published
1994

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