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168 results on '"H. Clement"'

1. Search for the η mesic He3 in the pd→dpπ0 reaction with the WASA-at-COSY facility

Author

M. Bashkanov, Markus Büscher, Izabela Ciepał, A. Erven, A. Goswami, A.E. Bondar, H. P. Morsch, P. Fedorets, Hans Stockhorst, Akira Yamamoto, Frank Goldenbaum, B. Mariański, Steven D. Bass, Rolf Stassen, K. Fransson, Hans Calén, Magdalena Skurzok, S. Schadmand, A. Khoukaz, Satoru Hirenzaki, Günter Kemmerling, Marcin Zieliński, P. Kulessa, W. Eyrich, A. Kupść, N. Hüsken, Di. Kirillov, W. Augustyniak, D. Pszczel, H. Ohm, K. Pysz, B. Kamys, T. Sefzick, Stanisław Kistryn, T. Johansson, Wiktor Parol, W. Erven, R. Engels, P. Wüstner, Lena Heijkenskjöld, D. Prasuhn, Paweł Moskal, G. Sterzenbach, B. Lorentz, M. Żurek, D. Lersch, B. Kłos, P. Adlarson, N. G. Kelkar, V. Hejny, K. Föhl, H. Clement, N.M. Piskunov, B. Shwartz, J. Stepaniak, Jozef Zlomanczuk, M. Berłowski, H. Ströher, Pawel Marciniewski, Eryk Czerwiński, T. Skorodko, Harald Kleines, J. Ritman, S. Sawant, V. Serdyuk, A. Magiera, Jerzy Smyrski, Oleksandr Rundel, E. Stephan, K. Lalwani, Wojciech Krzemien, J. Zabierowski, Antoni Szczurek, V. Sopov, Ankhi Roy, Aleksander Khreptak, K. Grigoryev, R. Maier, Aleksandra Wrońska, E. Perez del Rio, K. Demmich, F. S. Bergmann, and Magnus Wolke

Subjects
Excitation function, Physics, Meson production, Proton, 010308 nuclear & particles physics, chemistry.chemical_element, Resonance, 01 natural sciences, Nuclear physics, chemistry, 0103 physical sciences, Bound state, Pi, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Helium
Abstract

The excitation function for the $pd\rightarrow$ $d p \pi^{0}$ reaction has been measured by WASA-at-COSY experiment with the aim of searching for $^{3}\hspace{-0.03cm}\mbox{He}$-$\eta$ mesic nuclei. The measurement in the vicinity of $\eta$ meson production was performed using a ramped proton beam. The data analysis and interpretation was carried out with the assumption that the $\eta$-mesic Helium decays via the formation of an intermediate N$^{*}$(1535) resonance. No direct signal of the $\eta$-mesic nucleus is observed in the excitation function. We determine a new improved upper limit for the total cross section for the bound state production and decay in the $pd\rightarrow$ $(^{3}\hspace{-0.03cm}\mbox{He}$-$\eta)_{bound} \rightarrow$ $d p \pi^{0}$ process. It varies between 13 nb to 24 nb for the bound state with width in the range $\Gamma \in (5,50)$ MeV.

Published
2020

2. Differential cross sections for neutron-proton scattering in the region of the d*(2380) dibaryon resonance

Author

C.-O. Gullström, Markus Büscher, D. Pszczel, P. Podkopał, Pawel Marciniewski, S. Sawant, Paweł Moskal, R. Varma, P. Fedorets, I. Ozerianska, R. Maier, A. Švarc, J. Ritman, W. Eyrich, T. Sefzick, V. Serdyuk, P. Goslawski, E. Stephan, Jerzy Smyrski, P. Kulessa, N. Hüsken, B. Kamys, V. Hejny, K. Föhl, R. Engels, A. Pricking, P. Wüstner, H. Clement, Günter Kemmerling, A. Kupść, M. Mikirtychiants, A. Pyszniak, W. Augustyniak, D. Lersch, Izabela Ciepał, A. Goswami, Magdalena Skurzok, M. Bashkanov, Frank Goldenbaum, M. Krapp, K. Demmich, K. Pysz, B. Kłos, A. Magiera, Ferdous Khan, J. Zabierowski, Akira Yamamoto, Hans Stockhorst, M. Berłowski, A. Erven, H. Ströher, W. Erven, G. Sterzenbach, Antoni Szczurek, B. Lorentz, Rolf Stassen, Tord Johansson, K. Fransson, H. P. Morsch, Zbigniew Rudy, T. Skorodko, V. Sopov, H. Ohm, K. Grigoryev, A. Trzcinski, A. Khoukaz, S. Schadmand, P. Żuprański, A. Zink, Jozef Zlomanczuk, B. Mariański, R. Siudak, A. Täschner, I. I. Strakovsky, E. Doroshkevich, Aleksandra Wrońska, A. Jany, K. Lalwani, Eryk Czerwiński, Hans Calén, Stanisław Kistryn, W. Bardan, W. J. Briscoe, E. Perez del Rio, Ankhi Roy, Wojciech Krzemien, M. Hodana, J. Stepaniak, C. F. Redmer, F. S. Bergmann, Magnus Wolke, Harald Kleines, Di. Kirillov, F. Hauenstein, Lena Heijkenskjöld, D. Prasuhn, P. Wurm, Patrik Adlarson, Bo Höistad, D. Coderre, L. Yurev, Benedykt R. Jany, Himani Bhatt, N.M. Piskunov, Ron L. Workman, M. Żurek, and Marcin Zieliński

Subjects
Physics, Nuclear physics, Range (particle radiation), Hydrogen, chemistry, Deuterium, Scattering, chemistry.chemical_element, Neutron, Nuclear Experiment, Resonance (particle physics), Beam (structure), Differential (mathematics)
Abstract

Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized np scattering performed in the energy region of the d*(2380) dibaryon resonance covering the range of beam energies Tn=0.98−1.29 GeV (s=2.32−2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp→np+pspectator. In this way the np differential cross section σ(Θ) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power Ay(Θ) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D33-G33 waves.

Published
2020

3. Role of the d⁎(2380) dibaryon in NN interaction

Author

M. N. Platonova, H. Clement, V. N. Pomerantsev, O. A. Rubtsova, and V. I. Kukulin

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Scattering, Nuclear Theory, Phase (waves), 01 natural sciences, Resonance (particle physics), lcsh:QC1-999, Nuclear physics, Position (vector), 0103 physical sciences, 010306 general physics, Nuclear Experiment, lcsh:Physics
Abstract

It is demonstrated for the first time that the dibaryon resonance d ⁎ ( 2380 ) discovered reliably in the numerous experiments at the WASA@COSY facility (Julich FZ) determines almost completely (when supplemented with the peripheral one-pion exchange) NN scattering phase shifts and inelasticities in the coupled partial-wave channels D 3 3 – G 3 3 not only near the resonance position, but also in a broad energy range from zero up to about 1 GeV.

Published
2020

4. Three-nucleon dynamics in dp breakup collisions using the WASA detector at COSY-Jülich

Author

Jozef Zlomanczuk, P. Kulessa, K. Pysz, A. Kupść, Ankhi Roy, J. Zabierowski, A. Trzcinski, Antoni Szczurek, B. Kłos, Aleksandra Wrońska, E. Perez del Rio, A. Deltuva, T. Sefzick, R. Maier, D. Lersch, W. Augustyniak, D. Pszczel, Frank Goldenbaum, S. Schadmand, Eryk Czerwiński, K. Lalwani, S. Sawant, H. P. Morsch, M. Żurek, Harald Kleines, W. Erven, A. Kozela, Jacek Golak, Oleksandr Rundel, Wojciech Krzemien, B. Kamys, P. Żuprański, R. Skibiński, Marcin Zieliński, R. Engels, P. Wüstner, B. Shwartz, J. Stepaniak, Paweł Moskal, W. Eyrich, E. Stephan, A. Magiera, F. S. Bergmann, A. Wilczek, Magnus Wolke, N. Hüsken, V. Sopov, W. Bardan, B. Mariański, M. Berłowski, Patrik Adlarson, Magdalena Skurzok, Hans Calén, Akira Yamamoto, M. Bashkanov, T. Skorodko, Pawel Marciniewski, A. Erven, H. Ströher, K. Fransson, K. Demmich, J. Ritman, Tord Johansson, Henryk Witała, V. Serdyuk, Jerzy Smyrski, K. Grigoryev, L. Jarczyk, A. Khoukaz, Izabela Ciepał, A. Goswami, Hans Stockhorst, Rolf Stassen, G. Sterzenbach, B. Lorentz, Stanisław Kistryn, Lena Heijkenskjöld, D. Prasuhn, V. Hejny, K. Föhl, Günter Kemmerling, Markus Büscher, I. Skwira-Chalot, P. Fedorets, Wiktor Parol, N.M. Piskunov, H. Clement, Di. Kirillov, A.E. Bondar, and Aleksander Khreptak

Subjects
Physics, Scattering cross-section, дейтроны, нуклоны, 010308 nuclear & particles physics, Dynamics (mechanics), Detector, Nuclear Theory, Breakup, 01 natural sciences, dp-развал, Nuclear physics, Deuterium, 0103 physical sciences, Physics::Accelerator Physics, ddc:530, протоны, 010306 general physics, Nucleon, Nuclear Experiment, Beam energy
Abstract

The differential cross section for the 1H(d,pp)n breakup reaction at deuteron beam energy of 340 MeV has been measured with the use of the WASA detector at COSY-Jülich. The set of proton-proton coincidences registered at the Forward Detector has been analyzed on a dense grid of kinematic variables, giving in total around 5600 data points. The cross-section data are compared to theoretical predictions based on the state-of-the-art nucleon-nucleon potentials, combined with a three-nucleon force or the Coulomb interaction or carried out in a relativistic regime.

Published
2020

5. Examination of the production of an isotensor dibaryon in the pp→ppπ+π− reaction

Author

Zbigniew Rudy, Akira Yamamoto, O. Khreptak, A. Khoukaz, Eryk Czerwiński, B. Kamys, P. Żuprański, K. Fransson, Harald Kleines, Oleksandr Rundel, R. Engels, D. Lersch, P. Wüstner, H. P. Morsch, H. Clement, Hans Calén, E. Stephan, Jozef Zlomanczuk, T. Sefzick, W. Erven, A.E. Bondar, W. Eyrich, Wiktor Parol, Markus Büscher, M. Bashkanov, N. Hüsken, Pawel Marciniewski, A. Erven, Paweł Moskal, K. Pysz, M. Berłowski, D. Pszczel, A. Magiera, P. Fedorets, J. Ritman, T. Skorodko, Izabela Ciepał, A. Goswami, Di. Kirillov, B. Mariański, V. Serdyuk, H. Ströher, Stanisław Kistryn, P. Kulessa, Jerzy Smyrski, V. Hejny, K. Föhl, I. Schätti-Ozerianska, A. Trzcinski, S. Schadmand, Hans Stockhorst, B. Shwartz, J. Stepaniak, N.M. Piskunov, Lena Heijkenskjöld, W. Augustyniak, D. Prasuhn, V. Sopov, Rolf Stassen, G. Sterzenbach, B. Lorentz, Wojciech Krzemien, W. Bardan, Günter Kemmerling, J. Zabierowski, Antoni Szczurek, Aleksandra Wrońska, Ankhi Roy, E. Perez del Rio, M. Żurek, Marcin Zieliński, R. Maier, K. Grigoryev, L. Jarczyk, S. Sawant, F. S. Bergmann, Magnus Wolke, K. Demmich, K. Lalwani, A. Kupść, T. Johansson, B. Kłos, P. Adlarson, Magdalena Skurzok, H. Ohm, and Frank Goldenbaum

Subjects
Nuclear physics, Physics, Cross section (physics), Pion, Meson, 010308 nuclear & particles physics, Isospin, 0103 physical sciences, 010306 general physics, 7. Clean energy, 01 natural sciences, Resonance (particle physics)
Abstract

The quasifree pp → ppπ+π− reaction has been measured by means of pd collisions at Tp = 1.2 GeV using the WASA detector setup at COSY enabling exclusive and kinematically complete measurements. Total and differential cross sections have been extracted for the energy region Tp = 1.08–1.36 GeV (√s = 2.35–2.46 GeV) covering thus the regions of N∗(1440) and (1232)(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange as well as isospin relations based on the pp → ppπ0π0 data underpredict substantially the measured total cross section. The calculations are also at variance with specific experimental differential cross sections. An isotensor N dibaryon resonance with I (J P ) = 2(1+) produced associatedly with a pion is able to overcome these deficiencies. Such a dibaryon was predicted by Dyson and Xuong [Phys. Rev. Lett. 13, 815 (1964)] and more recently calculated by A. Gal and H. Garcilazo [Nucl. Phys. A 928, 73 (2014)].

Published
2019

6. Search for an isospin I= 3 dibaryon

Author

A.E. Bondar, Izabela Ciepał, O. Khreptak, Hans Stockhorst, Pawel Marciniewski, Rolf Stassen, Frank Goldenbaum, M. Berłowski, A. Magiera, J. Stepaniak, Jozef Zlomanczuk, J. Ritman, T. Skorodko, W. Erven, Di. Kirillov, Oleksandr Rundel, A. Zink, Paweł Moskal, V. Serdyuk, H. Bhatt, W. Eyrich, P. Kulessa, H. P. Morsch, T. Sefzick, Jerzy Smyrski, B. Kamys, P. Żuprański, P. Wüstner, D. Lersch, E. Stephan, M. Żurek, C.-O. Gullström, N. Hüsken, Markus Büscher, Günter Kemmerling, S. Schadmand, Zbigniew Rudy, N.M. Piskunov, A. Pyszniak, W. Augustyniak, A. Kuzmin, Hans Calén, M. Bashkanov, Eryk Czerwiński, K. Pysz, P. Fedorets, H. Clement, G. Khatri, Ferdous Khan, Kjell Fransson, Rudolf Maier, V. Hejny, A. Erven, Stanisław Kistryn, Harald Kleines, Akira Yamamoto, A. Kupść, K. Sitterberg, W. Bardan, Lena Heijkenskjöld, D. Prasuhn, B.A. Shwartz, A. Khoukaz, R. Varma, G. Sterzenbach, B. Lorentz, Ralf Engels, J. Zabierowski, Ankhi Roy, K. Föhl, Antoni Szczurek, H. Ströher, A. Trzcinski, Wojciech Krzemien, V. Sopov, D. Pszczel, I. Schätti-Ozerianska, Marcin Zieliński, P. Adlarson, H. Ohm, B. Mariański, Aleksandra Wrońska, E. Perez del Rio, Magdalena Skurzok, F. S. Bergmann, Magnus Wolke, K. Grigoryev, L. Jarczyk, A. Goswami, K. Demmich, T. Johansson, B. Kłos, K. Lalwani, and S. Sawant

Subjects
Nuclear and High Energy Physics, Particle physics, Pion-Production, Gev/C, Nuclear Theory, Hadron, FOS: Physical sciences, 01 natural sciences, Pp Collisions, High Energy Physics - Experiment, Subatomär fysik, Nuclear physics, High Energy Physics - Experiment (hep-ex), dibaryons, Subatomic Physics, 0103 physical sciences, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Proton-Proton Interactions, Physics, Quantum chromodynamics, States, Decomposition, Four-pion production, Dibaryons, 010308 nuclear & particles physics, Resonance, Quantum number, lcsh:QC1-999, Energies, Delta, Resonances, Isospin, four-pion production, 24 Gev-C, Beam energy, lcsh:Physics
Abstract

Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance d⁎(2380) with I(JP)=0(3+) there should also exist a dibaryon resonance with mirrored quantum numbers I(JP)=3(0+). We report here on a search for such a NN-decoupled state in data on the pp→ppπ+π+π−π− reaction. Since no clear-cut evidence has been found, we give upper limits for the production cross section of such a resonance in the mass range 2280–2500 MeV., This work has been supported by DFG (CL 214/3-1), STFC (ST/L00478X/1) and by the Polish National Science Center through grants Nos. DEC-2013/11/N/ST2/04152 and 2011/03/B/ST2/01847

Published
2016

7. Corrigendum to 'Isoscalar single-pion production in the region of Roper and d⁎(2380) resonances' [Phys. Lett. B 774 (2017) 599]

Author

A. Khoukaz, K. Grigoryev, P. Fedorets, P. Żuprański, P. Wüstner, R. Stassen, W. Eyrich, Wiktor Parol, B. Kamys, A. Bondar, Hans Calén, C.-O. Gullström, Aleksandra Wrońska, H. Clement, E. Perez del Rio, Kjell Fransson, A. Trzciński, M. Bashkanov, A. Pyszniak, W. Augustyniak, Izabela Ciepał, Magnus Wolke, V. Serdyuk, A. Magiera, Zbigniew Rudy, A. Yamamoto, H. Kleines, A. Kupść, Eryk Czerwiński, H.-P. Morsch, Pawel Marciniewski, A. Roy, Marcin Zieliński, H. Ohm, H. Stockhorst, K. Pysz, L. Jarczyk, G. Sterzenbach, P. Kulessa, Stanisław Kistryn, N.M. Piskunov, B. Shwartz, K. Sitterberg, B. Lorentz, K. Lalwani, K. Demmich, R. Varma, J. Ritman, W. Bardan, Lena Heijkenskjöld, G. Khatri, Paweł Moskal, D.A. Kirillov, Jerzy Smyrski, T. Sefzick, M. Büscher, F. Goldenbaum, G. Kemmerling, R. Maier, T. Johansson, B. Kłos, A. Kuzmin, D. Prasuhn, S. Sawant, F.S. Bergmann, A. Goswami, T. Skorodko, V. Hejny, N. Hüsken, J. Stepaniak, Himani Bhatt, S. Schadmand, D. Lersch, B. Mariański, V. Sopov, P. Adlarson, Oleksandr Rundel, Magdalena Skurzok, M. Berłowski, D. Pszczel, H. Ströher, R. Engels, I. Schätti-Ozerianska, W. Erven, J. Zabierowski, Wojciech Krzemien, E. Stephan, A. Szczurek, K. Föhl, A. Erven, M. Żurek, O. Khreptak, and Jozef Zlomanczuk

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Pion, Isoscalar, ddc:530, lcsh:Physics, lcsh:QC1-999
Published
2020

8. Search for η mesic 3He with the WASA-at-COSY facility in the pd→3He2γ and pd→3He6γ reactions

Author

Jozef Zlomanczuk, A. Trzcinski, W. Bardan, A. Magiera, V. Hejny, R. Maier, S. Sawant, James Ritman, Aleksandra Wrońska, E. Perez del Rio, B. Kamys, K. Grigoryev, Izabela Ciepał, D. Pszczel, B. Mariański, P. Wüstner, B.A. Shwartz, A.E. Bondar, T. Sefzick, Akira Yamamoto, A. Kupść, Hans Stockhorst, I. Schätti–Ozerianska, V. Sopov, D. Lersch, Rolf Stassen, T. Johansson, L. Jarczyk, B. Kłos, G. Sterzenbach, B. Lorentz, Oleksandr Rundel, M. Żurek, S. Schadmand, Paweł Moskal, A. Goswami, Marcin Zieliński, E. Stephan, Wiktor Parol, Pawel Marciniewski, Ralf Engels, Di. Kirillov, P. Kulessa, W. Erven, H. Clement, Wojciech Krzemien, Satoru Hirenzaki, V. Serdyuk, M. Berłowski, Günter Kemmerling, Jerzy Smyrski, Stanisław Kistryn, W. Augustyniak, K. Föhl, Ankhi Roy, A. Khreptak, T. Skorodko, Lena Heijkenskjöld, D. Prasuhn, W. Eyrich, Magnus Wolke, Markus Büscher, J. Zabierowski, M. Bashkanov, N.M. Piskunov, Antoni Szczurek, N. G. Kelkar, A. Erven, H. Ströher, Eryk Czerwiński, Harald Kleines, K. Lalwani, Frank Goldenbaum, Steven D. Bass, P. Żuprański, Hans Calén, Kjell Fransson, K. Pysz, P. Fedorets, J. Stepaniak, H. P. Morsch, H. Ohm, P. Adlarson, and Magdalena Skurzok

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Eta meson, Detector, 01 natural sciences, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, Bound state, medicine, Order (group theory), High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleus
Abstract

We report on the experimental search for the bound state of an eta meson and He-3 nucleus performed using the WASA-at-COSY detector setup. In order to search for the eta-mesic nucleus decay, the pd ...

Published
2020

9. Backward single-pion production in the $ pd\rightarrow {}^{3}\mathrm{He} \pi^{0}$ p d → 3 He π 0 reaction with WASA-at-COSY

Author

Günter Kemmerling, Izabela Ciepał, A. Trzcinski, Aleksandra Wrońska, E. Perez del Rio, Hans Calén, Hans Stockhorst, W. Eyrich, Wojciech Krzemien, R. Maier, H. Ohm, D. Lersch, Rolf Stassen, N. Hüsken, Kjell Fransson, Jozef Zlomanczuk, K. Lalwani, G. Sterzenbach, P. Kulessa, Stanisław Kistryn, B. Lorentz, C. Wilkin, H. Clement, Lena Heijkenskjöld, Pawel Marciniewski, Ralf Engels, D. Prasuhn, Frank Goldenbaum, Oleksandr Rundel, B. Mariański, Paweł Moskal, B.A. Shwartz, A. Khoukaz, F. S. Bergmann, J. Zabierowski, Magnus Wolke, Magdalena Skurzok, N.M. Piskunov, T. Johansson, W. Erven, E. Stephan, H. Ströher, K. Föhl, A. Magiera, Antoni Szczurek, A. Kuzmin, Wiktor Parol, P. Żuprański, B. Kłos, D. Pszczel, James Ritman, S. Sawant, I. Schätti-Ozerianska, V. Serdyuk, A. Pyszniak, W. Augustyniak, V. Sopov, Jerzy Smyrski, K. Grigoryev, C.-O. Gullström, Markus Büscher, B. Kamys, M. Bashkanov, V. Hejny, Akira Yamamoto, P. Wüstner, A. Kupść, A. Erven, Marcin Zieliński, L. Jarczyk, W. Bardan, K. Sitterberg, P. Adlarson, A. Goswami, K. Demmich, S. Schadmand, G. Khatri, M. Berłowski, Ankhi Roy, T. Skorodko, T. Sefzick, Zbigniew Rudy, M. Żurek, Eryk Czerwiński, Harald Kleines, K. Pysz, P. Fedorets, J. Stepaniak, H. P. Morsch, Di. Kirillov, A. Khreptak, and A.E. Bondar

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, Proton, 010308 nuclear & particles physics, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Nuclear physics, Pion, 0103 physical sciences, Production (computer science), Nuclear Experiment, 010306 general physics, Isotopes of helium
Abstract

New data on the production of single neutral pions in the $ pd\rightarrow {}^{3}\mathrm{He} \pi^{0}$ reaction are presented. For fifteen proton beam momenta between $ p_{p}=1.60$ GeV/c and $ p_{p}=1.74$ GeV/c, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.

Published
2018

10. Isotensor Dibaryon in the pp→ppπ+π− Reaction?

Author

A. Magiera, Stanisław Kistryn, O. Khreptak, H. Clement, A. Bondar, B. Shwartz, J. Stepaniak, Lena Heijkenskjöld, D. Prasuhn, K. Lalwani, H. Ohm, D. Lersch, W. Erven, T. Johansson, Jozef Zlomanczuk, H. P. Morsch, G. Sterzenbach, B. Lorentz, Ralf Engels, Pawel Marciniewski, B. Kłos, Wiktor Parol, A. Khoukaz, D. Pszczel, K. Föhl, H. Ströher, Izabela Ciepał, F. S. Bergmann, K. Pysz, P. Fedorets, W. Augustyniak, J. Ritman, V. Serdyuk, S. Sawant, Frank Goldenbaum, Jerzy Smyrski, Aleksandra Wrońska, E. Perez del Rio, Hans Stockhorst, Magnus Wolke, V. Hejny, M. Bashkanov, I. Schätti-Ozerianska, T. Sefzick, S. Schadmand, Akira Yamamoto, A. Kupść, A. Trzcinski, Marcin Zieliński, Rolf Stassen, A. Erven, Di. Kirillov, P. Żuprański, B. Kamys, Markus Büscher, W. Eyrich, Günter Kemmerling, P. Wüstner, N. Hüsken, Hans Calén, P. Adlarson, K. Grigoryev, Kjell Fransson, Magdalena Skurzok, M. Żurek, Paweł Moskal, L. Jarczyk, M. Berłowski, Wojciech Krzemien, R. Maier, A. Goswami, K. Demmich, T. Skorodko, B. Mariański, J. Zabierowski, Antoni Szczurek, Zbigniew Rudy, Eryk Czerwiński, Harald Kleines, V. Sopov, W. Bardan, Oleksandr Rundel, E. Stephan, P. Kulessa, N.M. Piskunov, and Ankhi Roy

Subjects
Nuclear physics, Physics, Cross section (physics), Pion, Meson, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, General Physics and Astronomy, 010306 general physics, 01 natural sciences, Resonance (particle physics), Energy (signal processing)
Abstract

Exclusive measurements of the quasifree pp→ppπ^{+}π^{-} reaction have been carried out at WASA@COSY by means of pd collisions at T_{p}=1.2 GeV. Total and differential cross sections have been extracted covering the energy region T_{p}=1.08-1.36 GeV, which is the region of N^{*}(1440) and Δ(1232)Δ(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor ΔN dibaryon resonance with I(J^{P})=2(1^{+}) produced associatedly with a pion is able to overcome these deficiencies.

Published
2018

11. Importance of -wave Contributions in the Charge Symmetry Breaking Reaction

Author

D. Lersch, O. Khreptak, M. Bashkanov, K. Grigoryev, A. Erven, K. Sitterberg, K. Föhl, Izabela Ciepał, H. Ströher, Oleksandr Rundel, A. Magiera, V. Sopov, T. Johansson, B. Kłos, Jozef Zlomanczuk, A. Trzcinski, L. Jarczyk, B.A. Shwartz, A. Khoukaz, Hans Stockhorst, G. Khatri, E. Stephan, Rolf Stassen, G. Sterzenbach, Marcin Zieliński, S. Sawant, B. Lorentz, N.M. Piskunov, A. Kuzmin, A. Goswami, J. Zabierowski, K. Demmich, C.-O. Gullström, Markus Büscher, Antoni Szczurek, W. Bardan, S. Schadmand, D. Pszczel, Rudolf Maier, Ankhi Roy, P. Kulessa, P. Adlarson, J. Stepaniak, W. Erven, Wiktor Parol, Zbigniew Rudy, I. Schätti-Ozerianska, K. Lalwani, Magdalena Skurzok, Eryk Czerwiński, B. Mariański, Aleksandra Wrońska, K. Pysz, P. Fedorets, Harald Kleines, E. Perez del Rio, Hans Calén, B. Kamys, P. Wüstner, F. S. Bergmann, Wojciech Krzemien, Magnus Wolke, M. Berłowski, H. P. Morsch, H. Ohm, Kjell Fransson, H. Clement, Frank Goldenbaum, T. Skorodko, T. Sefzick, Pawel Marciniewski, P. Żuprański, M. Żurek, J. Ritman, V. Serdyuk, Jerzy Smyrski, Ralf Engels, Günter Kemmerling, W. Eyrich, N. Hüsken, Christoph Hanhart, Stanisław Kistryn, Lena Heijkenskjöld, D. Prasuhn, A. Pyszniak, W. Augustyniak, Paweł Moskal, V. Hejny, Akira Yamamoto, A. Kupść, Di. Kirillov, and A.E. Bondar

Subjects
Physics, Quark, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Spontaneous symmetry breaking, Hadron, Charge (physics), 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, Isobar, Symmetry breaking, Atomic physics, 010306 general physics
Abstract

This letter reports a first quantitative analysis of the contribution of higher partial waves in the charge symmetry breaking reaction dd→4Heπ0 using the WASA-at-COSY detector setup at an excess energy of Q=60MeV. The determined differential cross section can be parametrized as dσ/dΩ=a+bcos2⁡θ⁎, where θ⁎ is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a=(1.55±0.46(stat)+0.32−0.8(syst))pb/sr and b=(13.1±2.1(stat)−2.7+1.0(syst))pb/sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the Δ isobar to the dd→4Heπ0 reaction and is, therefore, crucial for a quantitative understanding of quark mass effects in nuclear production reactions.

Published
2018

12. Total and differential cross sections of η -production in proton–deuteron fusion for excess energies between Q η = 13 MeV and Q η = 81 MeV

Author

B.A. Shwartz, A. Khoukaz, M. Bashkanov, A. Erven, K. Sitterberg, Hans Calén, K. Grigoryev, Stanisław Kistryn, D. Pszczel, P. Adlarson, Kjell Fransson, K. Pysz, P. Fedorets, D. Lersch, A. Khreptak, S. Schadmand, H. Clement, Ankhi Roy, A. Pyszniak, W. Augustyniak, Günter Kemmerling, H. Ströher, K. Lalwani, I. Schätti-Ozerianska, L. Jarczyk, Zbigniew Rudy, Lena Heijkenskjöld, D. Prasuhn, P. Kulessa, C.-O. Gullström, Frank Goldenbaum, T. Johansson, F. S. Bergmann, Eryk Czerwiński, W. Eyrich, B. Kłos, W. Erven, Magnus Wolke, Wiktor Parol, Markus Büscher, J. Stepaniak, Pawel Marciniewski, N. Hüsken, Harald Kleines, C. Wilkin, Izabela Ciepał, S. Sawant, A. Kuzmin, Jozef Zlomanczuk, J. Zabierowski, H. P. Morsch, G. Sterzenbach, B. Lorentz, P. Żuprański, A. Trzcinski, Hans Stockhorst, Di. Kirillov, Antoni Szczurek, G. Khatri, A. Magiera, V. Serdyuk, Paweł Moskal, James Ritman, Ralf Engels, Rolf Stassen, A. Goswami, Jerzy Smyrski, B. Kamys, K. Demmich, Wojciech Krzemien, P. Wüstner, Oleksandr Rundel, N.M. Piskunov, A.E. Bondar, R. Maier, V. Hejny, Akira Yamamoto, A. Kupść, Aleksandra Wrońska, E. Perez del Rio, E. Stephan, K. Föhl, Magdalena Skurzok, H. Ohm, V. Sopov, W. Bardan, B. Mariański, M. Berłowski, T. Skorodko, Marcin Zieliński, T. Sefzick, and M. Żurek

Subjects
Nuclear and High Energy Physics, eta meson, Proton, Meson, Hadron, Nuclear Theory, Elementary particle, η meson, 7. Clean energy, 01 natural sciences, Nuclear physics, Subatomär fysik, proton–deuteron interactions, Astronomi, astrofysik och kosmologi, 0103 physical sciences, протон-дейтронные взаимодействия, Subatomic Physics, Astronomy, Astrophysics and Cosmology, ddc:530, 010306 general physics, Nuclear Experiment, Boson, Physics, 010308 nuclear & particles physics, Eta meson, Meson production, lcsh:QC1-999, Deuterium, meson production, Proton-deuteron interactions, \eta meson, мезоны, Physics::Accelerator Physics, High Energy Physics::Experiment, ηмезоны, Beam (structure), lcsh:Physics
Abstract

New data on both total and differential cross sections of the production of η mesons in proton–deuteron fusion to He3η in the excess energy region 13.6MeV≤Qη≤80.9MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Jülich, using a proton beam at 15 different beam momenta between pp=1.60GeV/c and pp=1.74GeV/c. While significant structure of the total cross section is observed in the energy region 20MeV≲Qη≲60MeV, a previously reported sharp variation around Qη≈50MeV cannot be confirmed. Angular distributions show the typical forward-peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval.

Published
2018

13. Charge symmetry breaking in dd→He4π0 with WASA-at-COSY

Author

Izabela Ciepał, H. Bhatt, Hans Stockhorst, V. Sopov, D. Lersch, Marcin Zieliński, Rolf Stassen, A. Pricking, Bo Höistad, Jozef Zlomanczuk, A.S. Kuzmin, C.-O. Gullström, Markus Büscher, C. F. Redmer, A. Goswami, E. Doroshkevich, B. Mariański, Aleksandra Wrońska, E. Perez del Rio, P. Goslawski, K. Demmich, P. Wurm, H. Clement, K. Lalwani, Stanisław Kistryn, W. Eyrich, D. Coderre, R. Varma, M. Berłowski, A. Pyszniak, W. Augustyniak, K. Föhl, I. Ozerianska, W. Bardan, L. Yurev, P. Podkopał, S. Sawant, Lena Heijkenskjöld, F. S. Bergmann, A. Zink, Zbigniew Rudy, F. Hauenstein, D. Prasuhn, Paweł Moskal, R. Siudak, Magnus Wolke, T. Skorodko, N. Hüsken, Ankhi Roy, R. Maier, J. Stepaniak, W. Erven, P. Kulessa, Eryk Czerwiński, V. Hejny, S. Schadmand, Akira Yamamoto, A. Kupść, B. Kamys, T. Sefzick, Harald Kleines, P. Wüstner, K. Grigoryev, P. Adlarson, Christoph Hanhart, H. Ströher, E. Stephan, N.M. Piskunov, T. Johansson, M. Żurek, L. Jarczyk, B. Kłos, Wojciech Krzemien, K. Pysz, P. Fedorets, Ferdous Khan, Pawel Marciniewski, H. Ohm, V. Serdyuk, B.A. Shwartz, A. Khoukaz, H. P. Morsch, Jerzy Smyrski, M. Mikirtychiants, Magdalena Skurzok, M. Bashkanov, Günter Kemmerling, A. Trzciński, A. Erven, G. Sterzenbach, B. Lorentz, D. Pszczel, Ralf Engels, A. Täschner, A. Magiera, James Ritman, Frank Goldenbaum, P. Żuprański, A.E. Bondar, Hans Calén, Di. Kirillov, J. Zabierowski, Kjell Fransson, and Antoni Szczurek

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Chiral perturbation theory, 010308 nuclear & particles physics, Nuclear Theory, Observable, Charge (physics), 01 natural sciences, Nuclear physics, 0103 physical sciences, Sum rule in quantum mechanics, Symmetry breaking, Nuclear Experiment, 010306 general physics
Abstract

Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are cu ...

Published
2014

14. Spin dependence of {\eta} meson production in proton-proton collisions close to threshold

Author

M. Bashkanov, Günter Kemmerling, A. Erven, I. Schätti-Ozerianska, K. Sitterberg, G. Sterzenbach, W. Eyrich, A. Magiera, B. Lorentz, H. P. Morsch, O. Khreptak, Ralf Engels, N. Hüsken, Paweł Moskal, Zbigniew Rudy, Marcin Zieliński, Eryk Czerwiński, C.-O. Gullström, Markus Büscher, Harald Kleines, Ankhi Roy, W. Bardan, Aleksandra Wrońska, Hans Calén, E. Perez del Rio, T. Sefzick, Stanisław Kistryn, J. Zabierowski, K. Pysz, V. Hejny, Akira Yamamoto, Kjell Fransson, Lena Heijkenskjöld, D. Prasuhn, Antoni Szczurek, A. Khoukaz, Magdalena Skurzok, B. Mariański, K. Grigoryev, Jozef Zlomanczuk, Wojciech Krzemien, V. Sopov, Andrzej Kupsc, Patrik Adlarson, Frank Goldenbaum, Pawel Marciniewski, Damian Pszczel, B. Shwartz, J. Stepaniak, P. Zupranski, D. Lersch, J. Ritman, A. Trzcinski, G. Khatri, P. Fedorets, W. Augustyniak, Tord Johansson, L. Jarczyk, W. Erven, V. Serdyuk, Steven D. Bass, H. Ohm, H. Clement, M. Berłowski, K. Föhl, K. Lalwani, A. Bondar, H. Stroeher, Maria Zurek, Jerzy Smyrski, B. Kamys, P. Wüstner, B. Kłos, T. Skorodko, S. Schadmand, K. Demmich, A. Pyszniak, S. Sawant, Di. Kirillov, A. Kuzmin, F. S. Bergmann, Magnus Wolke, Izabela Ciepał, A. Goswami, Hans Stockhorst, Rolf Stassen, Rudolf Maier, P. Kulessa, Wiktor Parol, Oleksandr Rundel, E. Stephan, and N.M. Piskunov

Subjects
Nuclear Theory, General Physics and Astronomy, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, 0103 physical sciences, ddc:530, FACILITY, NEAR-THRESHOLD, 010306 general physics, NUCLEON, Nuclear Experiment, Nuclear theory, Physics, QUASI-FREE, 010308 nuclear & particles physics, Eta meson, Detector, COSY, Polarization (waves), Near threshold, High Energy Physics - Phenomenology, Physics::Accelerator Physics, Axial symmetry, Nucleon
Abstract

Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high degree of the polarized proton beam of COSY, the reaction pp{\to} pp{\eta} has been measured close to threshold to explore the analyzing power Ay. The angular distribution of Ay is determined with the precision improved by more than one order of magnitude with respect to previous results allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q = 15 MeV signaling s wave production with no evidence for higher partial waves. At Q = 72 MeV the data reveals strong interference of P s and P p partial waves and cancellation of (P p) and Ss*Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the {\eta} meson., Comment: Accepted for publication in Phys. Rev. Lett

Published
2017

15. Observation of the ABC effect and final-state isospin

Author

T. Yu Skorodko, G. J. Wagner, M. Bashkanov, E. Doroshkevich, A. Pricking, E. Perez del Rio, and H. Clement

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Isovector, Dalitz plot, Isoscalar, isovector channel, State (functional analysis), Atomic and Molecular Physics, and Optics, atomic nucleus, Nuclear physics, Isospin, Atomic nucleus, exclusive measurement, Nuclear fusion, Pi interaction, total cross section
Abstract

Despite the number of inclusive measurements of the pionic fusion reactions, the nature of the ABC effect discovered in 1960 was not completely established. Exclusive measurements of the doublepion-production reactions leading to either fused d, 3He and 4He nuclear final states or pp pairs are analyzed. A significant ABC effect—enhancement in the region of low ππ mass—is found only in the isoscalar ππ channel while in the isovector channels it is small or absent. For the reaction with isovector pp final state an ABC effect was not observed even at the special kinematic conditions to reproduce a quasi-bound two-proton state. The total cross sections for the d and 4He fusion reactions show similar resonance-like energy dependence.

Published
2014

16. Search for a dark photon in the π0→e+e−γ decay

Author

M. Mikirtychiants, Magdalena Skurzok, C. F. Redmer, Bo Höistad, G. J. Wagner, Jozef Zlomanczuk, A. Magiera, P. Goslawski, T. Sefzick, W. Eyrich, James Ritman, B. Mariański, C.-O. Gullström, Markus Büscher, H. Clement, Zbigniew Rudy, R. Siudak, Eryk Czerwiński, A. Trzcinski, Harald Kleines, Aleksandra Wrońska, Ulf-G. Meißner, A. Bondar, E. Perez del Rio, N. Shah, K. Pysz, P. Fedorets, Ferdous Khan, W. Zipper, P. Adlarson, W. Bardan, J. Zabierowski, K. Lalwani, Ankhi Roy, M. Hodana, Antoni Szczurek, P. Wurm, H. P. Morsch, H. Ohm, R. Varma, D. Pszczel, M. Żurek, Izabela Ciepał, T. Johansson, I. Ozerianska, V. Hejny, K. Föhl, B. Kłos, M. Siemaszko, Hans Stockhorst, V. Sopov, E. Stephan, H. Ströher, Marcin Zieliński, Frank Goldenbaum, S. Sawant, Pawel Marciniewski, F. Hauenstein, P. Podkopał, Rolf Stassen, K. Grigoryev, E. Doroshkevich, B. Shwartz, J. Stepaniak, Stanisław Kistryn, P. Pluciński, Alexander Schmidt, M. Krapp, P. Żuprański, F. Hinterberger, Hans Calén, R. Maier, Lena Heijkenskjöld, A. Jany, D. Prasuhn, Wojciech Krzemien, L. Li, Kjell Fransson, W. Wȩglorz, T. Tolba, Akira Yamamoto, A. Kupść, M. Berłowski, W. Erven, L. Jarczyk, Andreas Wirzba, A. Pricking, T. Skorodko, K. Demmich, V. Serdyuk, Di. Kirillov, G. Sterzenbach, B. Lorentz, Jerzy Smyrski, M. Bashkanov, F. S. Bergmann, Ralf Engels, Magnus Wolke, Paweł Moskal, Günter Kemmerling, S. Schadmand, B. Kamys, A. Pyszniak, W. Augustyniak, P. Wüstner, A. Goswami, A. Khoukaz, Himani Bhatt, Basanta Kumar Nandi, N.M. Piskunov, Benedykt R. Jany, P. Kulessa, A. Kuzmin, J. Klaja, D. Coderre, and D. Lersch

Subjects
Physics, Nuclear and High Energy Physics, Muon, Anomalous magnetic dipole moment, Magnetic moment, 010308 nuclear & particles physics, Elementary particle, 01 natural sciences, 7. Clean energy, Dark photon, Nuclear physics, Massless particle, Particle decay, 0103 physical sciences, 010306 general physics, Lepton
Abstract

The presently world largest data sample for π 0 → γ e + e − decays studies containing nearly 5 × 10 5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the π 0 → γ U → γ e + e − decay from the p p → p p π 0 reaction was carried out. An upper limit on the square of the U − γ mixing strength parameter ϵ 2 of 5 × 10 − 6 at 90% CL was obtained for the mass range 20 MeV M U 100 MeV . This result together with other recent experimental limits significantly reduces the M U vs. ϵ 2 parameter space which could explain the presently seen deviation between the Standard Model prediction and the direct measurement of the anomalous magnetic moment of the muon.

Published
2013

17. Measurement of polarization observables of the associated strangeness production in proton proton interactions

Author

P. Wintz, F. Hauenstein, D. Grzonka, W. Eyrich, K. Kilian, P. Wüstner, Paweł Moskal, R. Dzhygadlo, T. Sefzick, L. Kober, W. Schroeder, M. Röder, H. Clement, M. Krapp, K. Ehrhardt, S. Jowzaee, E. Roderburg, E. Doroshkevich, P. Klaja, M. Mertens, A. Gillitzer, J. Ritman, Jerzy Smyrski, E. Borodina, and W. Gast

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Partial wave analysis, Polarization observables, Hadron, FOS: Physical sciences, Strangeness production, Physik (inkl. Astronomie), Polarization (waves), 01 natural sciences, Nuclear physics, 0103 physical sciences, Spin transfer, Nuclear fusion, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Excess energy
Abstract

The Lambda polarization, the analyzing power, and the Lambda spin transfer coefficient of the reaction pp -> p K+ Lambda were measured at beam momenta of 2.70 GeV/c and 2.95 GeV/c, corresponding to excess energies of 122 MeV and 204 MeV. While the analyzing power and the spin transfer coefficient do not change significantly with the excess energy, the Lambda polarization varies strongly and changes its sign. As this is the first measurement of polarization observables below an excess energy of 200 MeV, the change of the sign of the Lambda polarization was not observed before. The high statistics of the data (~200 k events for each momentum) enables detailed studies of the dependence of the Lambda polarization and the analyzing power on the center of mass momentum of the particles. The results of the spin transfer coefficient are in qualitative agreement with the DISTO experiment. The Lambda polarization data of 2.95 GeV/c are only conform with the DISTO experiment, while both the 2.70 GeV/c and 2.95 GeV/c data differ strongly from all previous measurements, whether exclusive or inclusive., Revised version as accepted for publication in EPJA

Published
2016

18. High-precision measurement of the associated strangeness production in proton-proton interactions

Author

T. Sefzick, R. Dzhygadlo, E. Borodina, F. Hauenstein, M. Krapp, L. Kober, E. Roderburg, P. Wintz, S. Jowzaee, M. Röder, James Ritman, K. Ehrhardt, W. Eyrich, Paweł Moskal, E. Doroshkevich, P. Klaja, H. Clement, M. Mertens, W. Schroeder, Jerzy Smyrski, A. Gillitzer, P. Wüstner, D. Grzonka, K. Kilian, and W. Gast

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Dalitz plot, Strangeness production, Physik (inkl. Astronomie), Lambda, 01 natural sciences, Helicity, Nuclear physics, 0103 physical sciences, Invariant mass, ddc:530, 010306 general physics, Wave function, Nuclear Experiment
Abstract

A new high-precision measurement of the reaction \(pp\rightarrow pK^{+}\Lambda\) at a beam momentum of 2.95 GeV/c with more than 200 000 analyzed events allows a detailed analysis of differential observables and their inter-dependencies. Correlations of the angular distributions with momenta are examined. The invariant mass distributions are compared for different regions in the Dalitz plots. The cusp structure at the \(N\Sigma\) threshold is described with the Flatte formalism and its variation in the Dalitz plot is analyzed.

Published
2016

19. Two-pion production in nucleon–nucleon collisions—Back to dibaryons?

Author

H. Clement

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Isovector, Isoscalar, Nuclear Theory, Nuclear physics, Pion, Intermediate state, Nuclear fusion, Invariant mass, Nuclear Experiment, Nucleon, Excitation
Abstract

The two-pion production in nucleon–nucleon collisions has been investigated systematically by exclusive and kinematically complete measurements at CELSIUS/WASA and more recently at COSY-TOF and particularly WASA@COSY. The data for all p p -induced isovector production channels in the energy range from threshold up to T p = 1.4 GeV can be well understood by t -channel Roper, Δ Δ and possibly Δ ( 1600 ) excitation. In contrast to that the purely isoscalar reaction channel p n → d π 0 π 0 exhibits a narrow resonance-like structure with m = 2.37 GeV and Γ = 70 MeV in the total cross section, which is correlated with an intriguing low-mass enhancement in the π π invariant mass spectrum (ABC effect) as well as with the formation of a Δ Δ system in the intermediate state. From the angular distributions the spin and parity of this structure have been derived resulting in I ( J P ) = 0 ( 3 + ) . The consequences of the resonance hypothesis for other reaction channels are discussed. The fact that also the double-pionic fusion reactions to 3He and 4He exhibit a corresponding resonance-like structure in the total cross section correlated with the ABC effect suggests that the underlying conjectured p n resonance is obviously robust enough to survive in nuclei.

Published
2012

20. Exclusive measurement of the η→π+π−γ decay

Author

Paweł Moskal, B. Lorentz, A. Magiera, Ulf-G. Meißner, M. Berłowski, H. P. Morsch, C. Adolph, C.-O. Gullström, Markus Büscher, B. Kamys, Benedykt R. Jany, A. Winnemöller, Jozef Zlomanczuk, James Ritman, Joanna Klaja, M. Mikirtychiants, D. Coderre, P. Wüstner, P. Goslawski, Magdalena Skurzok, R. Maier, G. J. Wagner, S. Schadmand, H. Clement, P. Fedorets, G. Sterzenbach, Günter Kemmerling, Bo Höistad, Paweł Podkopał, W. Eyrich, F. Stollenwerk, J. Heimlich, L. Jarczyk, A. Trzciński, T. Skorodko, A. Schmidt, Aleksandra Wrońska, A. Povtoreyko, E. Perez del Rio, X. Yuan, Tomasz Bednarski, Annika Passfeld, Zbigniew Rudy, H. Bhatt, W. Erven, Basanta Kumar Nandi, T. Sefzick, Stanisław Kistryn, J. Stepaniak, R. Engels, A. Pricking, D. Prasuhn, K. Föhl, R. Varma, P. Wurm, Andreas Wirzba, P. Pluciński, Eryk Czerwiński, K. T Brinkmann, K. Grigoryev, C. Zheng, Szymon Niedźwiecki, Harald Kleines, P. Vlasov, M. Hodana, W. Zipper, Lena Heijkenskjöld, W. Bardan, C. F. Redmer, P. Adlarson, P. Kulessa, T. Tolba, V. Serdyuk, R. Siudak, Hans Stockhorst, L. Yurev, Pawel Marciniewski, A. Täschner, H. Ohm, K. Pysz, T. Rausmann, Rolf Stassen, Christoph Hanhart, E. Doroshkevich, J. Zabierowski, F. Hinterberger, A. Jany, M. Siemaszko, Antoni Szczurek, Wojciech Krzemien, V. Sopov, F. S. Bergmann, Magnus Wolke, F. Kren, Jerzy Smyrski, Hans Calén, Kjell Fransson, T. Johansson, Frank Goldenbaum, B. Kłos, W. Węglorz, A. Pyszniak, W. Augustyniak, V. Hejny, S. Sawant, A. Kupść, Carla Terschlüsen, M. Bashkanov, P. Żuprański, Stefan Leupold, K. Lalwani, Y. Petukhov, A. Khoukaz, N.M. Piskunov, Marek Jacewicz, C. Pauly, N. Shah, Marcin Zieliński, H. Ströher, Ankhi Roy, O. Khakimova, B. Mariański, and T. Petri

Subjects
Physics, Nuclear and High Energy Physics, Proton, Meson, 010308 nuclear & particles physics, Nuclear Theory, Eta meson, Hadron, 01 natural sciences, 7. Clean energy, Nuclear physics, Pion, Helium-3, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Isotopes of helium, Dimensionless quantity
Abstract

An exclusive measurement of the decay eta -> pi(+) pi(-) gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd -> He-3 X at a proton be ...

Published
2012

21. π0π0 Production in proton–proton collisions at Tp=1.4 GeV

Author

Aleksandra Wrońska, E. Perez del Rio, A. Povtoreyko, P. Wurm, G. J. Wagner, A. Taeschner, L. Yurev, P. Zupranski, X. Yuan, Pawel Plucinski, Ankhi Roy, W. Eyrich, P. Kulessa, C. Zheng, C. F. Redmer, B. Kamys, Stanisław Kistryn, Annika Passfeld, W. Węglorz, A. Khoukaz, M. Hodana, M. Berłowski, A. Magiera, C. Adolph, P. Podkopał, Ulrich Wiedner, W. Augustyniak, A. Pricking, F. Goldenbaum, Lena Heijkenskjöld, James Ritman, Jozef Zlomanczuk, Hans Stockhorst, Basanta Kumar Nandi, D. Prasuhn, Marek Jacewicz, Ralf Engels, H. Bhatt, H. P. Morsch, N.M. Piskunov, C. Pauly, R. Maier, Bo Höistad, M. Buescher, F. Hinterberger, T. Skorodko, Benedykt R. Jany, A. Schmidt, K. Lalwani, W. Erven, T. Sefzick, M. Bashkanov, Paweł Moskal, A. Winnemoeller, S. Schadmand, P. Vlasov, W. Zipper, Zbigniew Rudy, Eryk Czerwiński, G. Kemmerling, Y. Petukhov, T. Tolba, R. Stassen, V. Serdyuk, Pawel Marciniewski, V. Hejny, Jerzy Smyrski, P. Goslawski, B. Kłos, H. Clement, S. Sawant, K. Foehl, C.-O. Gullström, N. Shah, Andrzej Kupsc, L. Jarczyk, J. Stepaniak, H. Kleines, G. Sterzenbach, J. Heimlich, Bernd Lorentz, E. Doroshkevich, K. Pysz, F. S. Bergmann, Magnus Wolke, Hans Calén, A. Jany, A. Trzciński, Tomasz Bednarski, R. Varma, K. Grigoryev, M. Siemaszko, Kjell Fransson, P. Fedorets, J. Klaja, D. Coderre, V. Sopov, F. Kren, S. Niedzwiecki, Wojciech Krzemien, H. Stroeher, Marcin Zieliński, J. Zabierowski, Antoni Szczurek, M. Mikirtychiants, Magdalena Skurzok, T. Rausmann, O. Khakimova, B. Mariański, P. Wuestner, Patrik Adlarson, Tord Johansson, H. Ohm, Michał Janusz, and K. T Brinkmann

Subjects
Physics, Baryon, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pion, Meson, Proton, Hadron, Pi, Elementary particle, Nucleon
Abstract

The reaction pp -> pp pi(0)pi(0) has been investigated at a beam energy of 1.4 GeV using the WASA-at-COSY facility. The total cross section is found to be (324 +/- 21(systematic) +/- 58(normaliz ...

Published
2012

22. ΔΔ excitation in proton–proton induced π0π0 production

Author

Wolfgang Scobel, Bo Höistad, S. Keleta, G. J. Wagner, S. Kullander, H. Petrén, Akira Yamamoto, E. Jiganov, H. Clement, O. Khakimova, G. Ivanov, T. Skorodko, C. Ekström, Hans Calén, Leif Gustafsson, Marek Jacewicz, Jozef Zlomanczuk, C. Pauly, Karin Schönning, I. Koch, E. Doroshkevich, M. Bashkanov, J. Zabierowski, R. Meier, Pawel Marciniewski, V. Tikhomirov, L. Demiroers, Y. Petukhov, K. Fransson, A. Kupść, T. Johansson, A. Povtorejko, P. Thörngren-Engblom, F. Kren, Magnus Wolke, D. Bogoslawsky, B. Morosov, B. Shwartz, J. Stepaniak, and R. J. M. Y. Ruber

Subjects
Nuclear physics, Delta, Physics, Nuclear and High Energy Physics, Proton, Degree Celsius, Pi, Atomic physics, Excitation
Abstract

Exclusive measurements of the pp -> pp pi(0)pi(0) reaction have been performed at CELSIUS/WASA at energies from threshold up to T-p = 1.3 GeV. Total and differential cross sections have been obt ...

Published
2011

23. Cross sections of the pp→K+Σ+n reaction close to threshold

Author

J. Urban, B. J. Roy, G. J. Wagner, G. Martinska, H. Clement, E. Dorochkevitch, A. Chatterjee, A. Sibirtsev, P. Hawranek, D. Kolev, P. von Rossen, Di. Kirillov, M. Lesiak, R. Jahn, A. Budzanowski, D. Protic, S. Kliczewski, N.M. Piskunov, R. Joosten, A. Magiera, R. Siudak, M. Kravcikova, F. Hinterberger, K. Kilian, I.M. Sitnik, K. Ulbrich, Da. Kirillov, Hartmut Machner, J. Ritman, and R. Tsenov

Subjects
Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, Hyperon, Elementary particle, Sigma baryon, Nuclear physics, Baryon, Mass spectrum, Invariant mass, Atomic physics, Nuclear Experiment
Abstract

We have measured inclusive data on K + -meson production in pp collisions at COSY Julich close to the hyperon production threshold and determined the hyperon–nucleon invariant mass spectra. The spectra were decomposed into three parts: Λp, Σ 0 p and Σ + n . The cross section for the Σ + n channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence.

Published
2010

24. Production of $ \eta$ and 3$ \pi$ mesons in the pd $ \rightarrow$ 3HeX reaction at 1360 and 1450 MeV

Author

Andrzej Kupsc, H. Clement, P.-E. Tegnér, R. Shafigullin, G. J. Wagner, V. Sopov, L. Demiroers, F. Kren, C. Pauly, I. Zartova, C. Ekstroem, Marek Jacewicz, B. Morosov, G. Ivanov, T. Johansson, W. Oelert, Magnus Wolke, K. Fransson, K. Schoenning, A. Povtorejko, Pawel Marciniewski, B. Shwartz, J. Stepaniak, V. Tikhomirov, A. Kuzmin, K. Lindberg, A. Turowiecki, E. Jiganov, Chr. Bargholtz, J. Zabierowski, M. Bashkanov, D. Bogoslawsky, Y. Petukhov, B. Hoeistad, Jozef Zlomanczuk, S. Kullander, M. Berłowski, T. Skorodko, Hans Calén, P. Thoerngren Engblom, L. Geren, Wolfgang Scobel, H. Petrén, S. Keleta, O. Khakimova, and Leif Gustafsson

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, media_common.quotation_subject, Eta meson, Kinetic energy, Asymmetry, Nuclear physics, Amplitude, Isospin, ddc:530, Invariant mass, Nucleon, media_common
Abstract

The cross sections of the pd -> 3He eta, pd -> 3He pi0 pi0 pi0 and pd -> 3He pi+ pi- pi0 reactions have been measured at beam kinetic energies T_p= 1360 MeV and T_p= 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the differential cross section dsigma/dOmega of the eta meson in the pd -> 3He eta reaction shows a strong forward-backward asymmetry in the CMS. The ratio between the pd -> 3He pi+ pi- pi0 and the pd -> 3He pi0 pi0 pi0 cross sections has been analysed in terms of isospin amplitudes. The reconstructed invariant mass distributions of the pi-pi, 3He-pi and 3He-2pi systems provide hints on the role of nucleon resonances in the 3pi production process.

Published
2010

25. Influence of N∗-resonances on hyperon production in the channel pp→K+Λp at 2.95, 3.20 and 3.30 GeV/c beam momentum

Author

E. Kuhlmann, W. Schroeder, T. Sefzick, M. Abdel-Bary, S. Dshemuchadse, B. Jakob, P. Zupranski, P. Schoenmeier, C. Fanara, J. Hauffe, N. Paul, K. Ehrhardt, J. Dietrich, H. Jaeger, A. Erhardt, K. Kilian, S. AbdEl-Samad, H. P. Morsch, S. Marcello, S. Wirth, J. Waechter, S. Marwinski, W. Gast, G. J. Wagner, A. Wilms, H. Moertel, Marc Wagner, M. Krapp, K. Moeller, W. Eyrich, D. Hesselbarth, P. Wintz, J. Gottwald, P. Wüstner P Zupranski, H. Clement, A. Teufel, A. Metzger, Herbert Koch, C. Plettner, J. Ritman, E. Dorochkevitch, W. Ullrich, M. Fritsch, A. Schamlott, Leonhard Karsch, A. Filippi, Jens-Christoph Georgi, L. Naumann, A. Gillitzer, C. Pizzolotto, F. Stinzing, S. Mauro, M. Steinke, K. Brinkmann, W. Meyer, S. Reimann, Wüstner, M. Schulte-Wissermann, J. Kress, A. Lehmann, P. Michel, L. Pinna, H. Freiesleben, M. Richter, R. Wenzel, G. Y. Sun, Detlef Filges, R. Jaekel, and E. Roderburg

Subjects
Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Spectrometer, Hyperon, Resonance, Dalitz plot, Production (computer science), Lambda, Beam (structure)
Abstract

Hyperon production in the threshold region was studied in the reaction pp → K + Λ p using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at the three different beam momenta of p beam = 2.95 , 3.20 and 3.30 GeV/c, corresponding to excess energies of e = 204 , 285 and 316 MeV, respectively. Total cross-sections were deduced for the three beam momenta to be 23.9 ± 0.8 ± 2.0 μb , 28.4 ± 1.3 ± 2.2 μb and 35.0 ± 1.3 ± 3.0 μb . Differential observables including Dalitz plots were obtained. The analysis of the Dalitz plots reveals a strong influence of the N ( 1650 ) -resonance at p beam = 2.95 GeV / c , whereas for the higher momenta an increasing relative contribution of the N ( 1710 ) - and/or of the N ( 1720 ) -resonance was observed. In addition, the pΛ-final-state interaction turned out to have a significant influence on the Dalitz plot distribution.

Published
2010

26. Systematic study of the pp $ \rightarrow$ pp$ \omega$ reaction

Author

M. Schulte-Wissermann, A. Gillitzer, S. Reimann, C. Pizzolotto, A. Lehmann, Marc Wagner, René Jäkel, M. Krapp, Herbert Koch, P. Michel, M. Fritsch, M. Richter, P. Wintz, K. Ehrhardt, A. Erhardt, S. Dshemuchadse, J. Kreß, J. Dietrich, A. Teufel, G. J. Wagner, H. Freiesleben, H. Clement, Leonhard Karsch, K.-Th. Brinkmann, W. Eyrich, A. Filippi, W. Ullrich, B. Jakob, P. Schönmeier, A. Wilms, L. Naumann, K. Kilian, S. Marcello, J. Ritman, R. Wenzel, P. Wüstner, G. Y. Sun, W. Gast, A. Schamlott, S. Abdel-Samad, K. Möller, Ch. Plettner, H. P. Morsch, M. Steinke, E. Roderburg, S. Mauro, N. Paul, H. M. Jäger, J. Gottwald, W. Schroeder, T. Sefzick, P. Zupranski, E. Doroshkevich, E. Kuhlmann, and M. Abdel-Bary

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Proton, Phase space, Resonance, Invariant mass, Nuclear Experiment, Anisotropy, Omega, Helicity, Reference frame
Abstract

A systematic study of the production of omega-mesons in proton-proton-collisions was carried out in a kinematically complete experiment at three excess energies(epsilon= 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum J\"ulich. The total cross section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and, additionally, in Sd at epsilon= 173 MeV. No obvious indication of resonant omega-production via N^*-resonances was found, as proton angular distributions are almost isotropic and invariant mass spectra are compatible with phase space distributions. A dominant role of ^3P_1 and ^1S_0 initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega-p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega-p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process.

Published
2010

27. Exclusive measurements of pp→dπ+π0: Double-pionic fusion without ABC effect

Author

Curt Ekstrom, Bo Höistad, R. J. M. Y. Ruber, P. Thörngren-Engblom, Magnus Wolke, B. Morosov, M. Bashkanov, Jozef Zlomanczuk, Andrzej Kupsc, B. Shwartz, J. Stepaniak, S. Keleta, I. Koch, O. Khakimova, V. Tikhomirov, Karin Schönning, P. Marciniewski, G. J. Wagner, Y. Petukhov, L. Demiroers, E. Jiganov, F. Kren, H. Clement, D. Bogoslawsky, Sven Kullander, J. Zabierowski, Leif Gustafsson, A. Povtorejko, Marek Jacewicz, Akira Yamamoto, G. Ivanov, Hans Calén, Tord Johansson, W Scobel, K. Fransson, Henrik Petrén, T. Skorodko, J. Greiff, R. Meier, and C. Pauly

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Fusion, Isovector, Pi
Abstract

Exclusive measurements of the reaction pp -> d pi(+)pi(0) have been carried out at T-p = 1.1 GeV at the CELSIUS storage ring using the WASA detector. The isovector pi(+)pi(0) channel exhibits no ...

Published
2010

28. The pd→He3ηπ0 reaction at Tp=1450 MeV

Author

Leif Gustafsson, F. Kren, A. Kuzmin, Tord Johansson, G. Ivanov, A. Povtorejko, M. Bashkanov, H. Petren, J. Zabierowski, Marek Jacewicz, W. Oelert, Karin Schönning, B. Shwartz, Y. Petukhov, M. Berłowski, Pia Thörngren Engblom, D. Bogoslawsky, P.-E. Tegnér, I. Zartova, V. Tikhomirov, T. Skorodko, A. Turowiecki, C. Pauly, K. Fransson, L. Demiroers, Magnus Wolke, R. Shafigullin, G. J. Wagner, C. Ekström, Hans Calén, Andrzej Kupsc, S. Kullander, P. Marciniewski, H. Clement, L. Geren, J. Zlomanczuk, S. Keleta, Bo Höistad, Wolfgang Scobel, V. Sopov, B. Morosov, C. Wilkin, C. Bargholtz, K. Lindberg, E. Jiganov, J. Stepaniak, and O. Khakimova

Subjects
Nuclear physics, Physics, Momentum, Nuclear and High Energy Physics, Photon, Meson, Isobar, Resonance, Invariant mass, Atomic physics, Nuclear Experiment, Phi meson, Storage ring
Abstract

The cross section for the pd -> He-3 eta pi(0) reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring. The He-3 was detected in coincidence with four photons from the decays of the two mesons. The data indicate that the production mechanism involves the formation of the Delta(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant mass distributions Of all three pairs of final particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the pi(0) momentum in the He-3 pi(0) system.

Published
2010

29. Exclusive measurement of two-pion production in the reaction

Author

P. Thörngren Engblom, Roger Ruber, P.-E. Tegnér, K. Lindberg, B. Morosov, A. Povtorejko, M. Bashkanov, R. Shafigullin, G. J. Wagner, E. Jiganov, H. Clement, Y. Petukhov, Colin Wilkin, S. Keleta, Karin Schönning, A. Kupść, M. Wolke, Hans Calén, B. Shwartz, J. Stepaniak, C. Pauly, A. Kuzmin, Kjell Fransson, G. Ivanov, A. Turowiecki, Jozef Zlomanczuk, Wolfgang Scobel, Marek Jacewicz, L. Demirörs, V. Sopov, W. Oelert, F. Kren, C. Ekström, L. Geren, O. Khakimova, A. Pricking, M. Berłowski, H. Petrén, T. Skorodko, S. Kullander, Bo Höistad, Leif Gustafsson, I. Zartova, D. Bogoslawsky, Pawel Marciniewski, V. Tikhomirov, Chr. Bargholtz, J. Zabierowski, and T. Johansson

Subjects
Nuclear reaction, Nuclear physics, Physics, Nuclear and High Energy Physics, Pion, Isospin, Pi
Abstract

The results from the first kinematically complete measurement of the reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar ππ-invariant mass ...

Published
2009

30. Measurement of the η→3π0 Dalitz plot distribution with the WASA detector at COSY

Author

H. Schneider, Paweł Klaja, R. Siudak, W. Zipper, H. Ohm, C. Adolph, M. Berłowski, B Hoeistad, M. Wolke, Hans Calén, Kjell Fransson, Stanisław Kistryn, H. Yamaoka, Serdyuk, Himani Bhatt, N. Paul, A. Magiera, Jozef Zlomanczuk, B. Kamys, C. Ekström, T. Johansson, D Duniec, B. Kłos, M. Buescher, O. Khakimova, U Bechstedt, D. Prasuhn, N. Shah, H. Clement, K. Grigoryev, T. Skorodko, N.M. Piskunov, T. Tolba, N Milke, R Jany, J. Bisplinghoff, J Majewski, Andrzej Kupsc, T Smolinski, A Winnemoeller, Rafał Czyżykiewicz, T. Sefzick, Wolfgang Scobel, H Machner, Akira Yamamoto, A. Bondar, W Migdal, M. Mikirtychiants, B. Borasoy, O Miklukho, M. Siemaszko, Christoph Hanhart, P Vlasov, P. Podkopał, Wojciech Krzemien, P. Kulessa, W. Erven, L. Jarczyk, L. Yurev, X. Yuan, W Weglorz, R. Maier, Alexander Schmidt, Zbigniew Rudy, W. Eyrich, K. Pysz, W. Schroeder, U.-G. Meissner, M Mittag, I Zychor, K. Zwoll, T. Rausmann, Aleksandra Wrońska, A Nawrot, A. Khoukaz, Eryk Czerwiński, J Rachowski, A Izotov, H. Stroeher, N Kimura, K Nandi, S. Schadmand, A Odoyo, Paweł Moskal, Michał Janusz, Harald Kleines, A Roy, S Belostotski, Marek Jacewicz, K Chandwani, C. Zheng, C. Pauly, G D'Orsaneo, A Heczko, Kyryanchuk, D Spoelgen, K Ulbrich, R Marciniewski, A. Pricking, R Wuestner, K. Kilian, R Salmin, Günter Kemmerling, F. Kren, A. Kuzmin, Damian Tomasz Gil, Sopov, R. Varma, W. Oelert, J Zielinski, I. Keshelashvili, F Redmer, J. Zabierowski, M. Bashkanov, J. Ritman, J. Klaja, M Angelstein, H. S. Xu, Antoni Szczurek, J. Stepaniak, Jerzy Smyrski, A Kowalczyk, A. Povtoreyko, R Nissler, P. Pluciński, Hejny, A. Trzciński, Roger Ruber, Frank Goldenbaum, O Felden, M. Hodana, Y. Petukhov, Andreas Wirzba, G. Sterzenbach, F. Hinterberger, Ralf Engels, A. Teufel, S. Kullander, and P. Fedorets

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Chiral perturbation theory, Proton, Nuclear Theory, Detector, Dalitz plot, Kinetic energy, Nuclear physics, Pion, Distribution (mathematics), Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

In the first production run of the WASA experiment at COSY, the eta decay into three neutral pions was measured in proton-proton interactions at a proton beam kinetic energy of 1.4 GeV. The Dalitz ...

Published
2009

31. ISOSPIN DECOMPOSITION OF pp → NNππ CROSS SECTIONS — DO WE SEE A SIGN OF Δ(1600) EXCITATION IN THE nnπ+π+ CHANNEL?

Author

Andrzej Kupsc, Pawel Marciniewski, V. Tikhomirov, Henrik Petterson, P. Thörngren-Engblom, A. A. Kuznetsov, Sven Kullander, E. Jiganov, Karin Schönning, H. Clement, A. Povtorejko, A. Turowiecki, M. Wolke, Hans Calén, B. Morosov, Jozef Zlomanczuk, M. Bashkanov, Kjell Fransson, B. Shwartz, J. Stepaniak, Bo Höistad, G. Ivanov, Y. Petukhov, J. Zabierowski, G. J. Wagner, Wolfgang Scobel, Tord Johansson, Curt Ekstrom, R. Meier, V. Sopov, F. Kren, Marek Jacewicz, C. Pauly, S. Keleta, D. Bogoslowsky, Akira Yamamoto, Roger Ruber, T. Skorodko, I. Koch, O. Khakimova, and Leif Gustafsson

Subjects
Delta, Physics, Nuclear and High Energy Physics, Particle physics, Astronomy and Astrophysics, Decomposition, Resonance (particle physics), Atomic and Molecular Physics, and Optics, Nuclear physics, Cross section (geometry), Isospin, Pi, Excitation, Sign (mathematics)
Abstract

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.

Published
2009

32. A threshold Cherenkov detector for separation using silica aerogel

Author

G. Vankova, J. Urban, B. J. Roy, P. von Rossen, A. Chatterjee, G. J. Wagner, A. Magiera, I. V. Slepnev, A. Budzanowski, F. Massmann, I.M. Sitnik, D. Kolev, R. Jahn, H. Clement, M. Kravcikova, F. Hinterberger, D. Protic, L. Jarczyk, R. Joosten, K. Ulbrich, R. Ziegler, Hartmut Machner, R. Siudak, K. Kilian, Di. Kirillov, J. Ernst, J. Munkel, J. Ritman, R. Tsenov, Jerzy Smyrski, S. Kliczewski, G. Martinska, P. Hawranek, N.M. Piskunov, and E. Dorochkevitsch

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Cherenkov detector, Nuclear Theory, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Particle identification, Particle detector, law.invention, Nuclear physics, Pion, law, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation, Spectrograph, Refractive index, Cherenkov radiation
Abstract

þ ðLpÞ K þ =pþ separation abstract A new threshold Cherenkov detector has been built for the detection of charged pions in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n ¼ 1:05 is applied as a radiator. The detector exhibits a very high detection efficiency for pions with momenta X900 MeV=c. Using two Cherenkov detectors in series a very high pion suppression factor of 10 5 was achieved.

Published
2008

33. Polarisation of the ω meson in the pd→He3ω reaction at 1360 and 1450 MeV

Author

P. Thörngren Engblom, A. Kupść, A. Povtorejko, S. Keleta, Bo Höistad, J. Stepaniak, Wolfgang Scobel, G. Ivanov, R. J. M. Y. Ruber, A. Kuzmin, K. Fransson, K. Lindberg, P.-E. Tegnér, Leif Gustafsson, Hans Calén, Marek Jacewicz, Magnus Wolke, P. Marciniewski, W. Oelert, H. Pettersson, S. Kullander, M. Bashkanov, Chr. Bargholtz, B. Shwartz, D. Bogoslawsky, Jozef Zlomanczuk, L. Demirörs, A. Turowiecki, F. Kren, J. Zabierowski, R. Shafigullin, G. J. Wagner, K. Schönning, T. Skorodko, Y. Petukhov, I. Zartova, C. Wilkin, C. Pauly, C. Ekström, V. Tikhomirov, L. Geren, O. Khakimova, H. Clement, T. Johansson, I. Koch, E. Jiganov, B. Morosov, M. Berlowski, and V. Sopov

Subjects
Physics, Nuclear and High Energy Physics, Meson production, Meson, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Coincidence, Nuclear physics, Near threshold, Low energy, OZI rule, High Energy Physics::Experiment, Tensor, Nuclear Experiment
Abstract

The tensor polarisation of ω mesons produced in the p d → He 3 ω reaction has been studied at two energies near threshold. The He 3 nuclei were detected in coincidence with the π 0 π + π − or π 0 γ decay products of the ω . In contrast to the case of ϕ -meson production, the ω mesons are found to be unpolarised. This brings into question the applicability of the Okubo–Zweig–Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.

Published
2008

34. Single $\mathrm{\ensuremath{\pi^{-}}}$ production in np collisions for excess energies up to 90 MeV

Author

A. Erhardt, E. Doroshkevich, René Jäkel, W. Eyrich, S. Dshemuchadse, K. Möller, Leonhard Karsch, A. Teufel, P. Wintz, H. Clement, L. Naumann, A. Gillitzer, J. Ritman, P. Wüstner, T. Sefzick, W. Schroeder, P. Zupranski, C. Pizzolotto, N. Paul, K. Kilian, A. Ucar, H. P. Morsch, E. Kuhlmann, M. Abdel-Bary, K.-Th. Brinkmann, M. Schulte-Wissermann, H. Freiesleben, and E. Roderburg

Subjects
Momentum, Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Range (particle radiation), Deuterium, Proton, Nuclear Theory, Neutron, Invariant mass, Nuclear Experiment, Spectral line
Abstract

The quasifree reaction $np\to pp\pim$ was studied in a kinematically complete experiment by bombarding a liquid hydrogen target with a deuteron beam of momentum 1.85 GeV/c and analyzing the data along the lines of the spectator model. In addition to the three charged ejectiles the spectator proton was also detected in the large-acceptance time-of-flight spectrometer COSY-TOF. It was identified by its momentum and flight direction thus yielding access to the Fermi motion of the bound neutron and to the effective neutron 4-momentum vector $\mathbb{P}_n$ which differed from event to event. A range of almost 90 MeV excess energy above threshold was covered. Energy dependent angular distributions, invariant mass spectra as well as fully covered Dalitz plots were deduced. Sizeable $pp$ FSI effects were found as were contributions of $p$ and $d$ partial waves. The behavior of the elementary cross section $\sigma_{01}$ close to threshold is discussed in view of new cross section data. In comparison with existing literature data the results provide a sensitive test of the spectator model.

Published
2008

35. Improved study of a possible Θ+ production in the pp→pK0Σ+ reaction with the COSY-TOF spectrometer

Author

P. Wüstner, R. Castelijns, K.-Th. Brinkmann, A. Ucar, H. P. Morsch, A. Teufel, S. Dshemuchadse, Jens-Christoph Georgi, K. Ehrhardt, H. Jäger, C. Pizzolotto, L. Pinna, A. Erhardt, H. Freiesleben, M. Schulte-Wissermann, J. Ritman, W. Eyrich, P. Wintz, M. Krapp, H. Clement, R. Wenzel, E. Roderburg, A. Lehmann, W. Gast, S. Schadmand, A. Gillitzer, P. Zupranski, E. Dorochkevitch, P. Schönmeier, W. Ullrich, T. Sefzick, S. Abdel-Samad, J. Dietrich, W. Schroeder, N. Paul, René Jäkel, E. Kuhlmann, Leonhard Karsch, M. Abdel-Bary, and K. Kilian

Subjects
Physics, Momentum, Nuclear physics, Baryon, Nuclear and High Energy Physics, Spectrometer, Incident beam, Resonance, Production (computer science), Pentaquark
Abstract

The p p → p K 0 Σ + reaction was investigated with the TOF spectrometer at COSY at 3.059 GeV / c incident beam momentum. The main objective was to clarify whether or not a narrow exotic S = + 1 resonance, the Θ + pentaquark, is populated at 1.53 GeV / c 2 in the p K 0 subsystem with a data sample of much higher statistical significance compared to the previously reported data in this channel. An analysis of these data does not confirm the existence of the Θ + pentaquark. This is expressed as an upper limit for the cross section σ ( p p → Σ + Θ + ) 0.15 μb at the 95% confidence level.

Published
2007

36. The pp→ppπππ reaction channels in the threshold region

Author

Marek Jacewicz, Leif Gustafsson, J. Zabierowski, Pia Thörngren Engblom, W. Oelert, G. Ivanov, B. Morosov, Jozef Zlomanczuk, Roger Ruber, Hans Calén, M. Bashkanov, B. Shwartz, J. Stepaniak, Wolfgang Scobel, I. Koch, C. Pauly, Magnus Wolke, Kjell Fransson, R. Meier, Curt Ekstrom, Pawel Marciniewski, V. Tchernyshev, Filippo Capellaro, V. Tikhomirov, Karin Schönning, Henrik Pettersson, E. Jiganov, A. Turowiecki, G. J. Wagner, Y. Petukhov, D. Bogoslawsky, H. Clement, V. Sopov, Bo Höistad, Andrzej Kupsc, Tord Johansson, Akira Yamamoto, S. Keleta, T. Skorodko, Sven Kullander, A. Povtorejko, A. A. Kuznetsov, and Ulrich Wiedner

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Range (particle radiation), Meson production, Pion, Isobar, Intermediate state, Atomic physics
Abstract

The cross section for direct neutral and charged three pion production in pp interactions was measured at excess energies in the range 160–216 MeV. That comprises the first measurement of the pp→ppπ0π0π0 reaction and the direct comparison with the pp→ppπ+π−π0 process. The experiment was performed above the η meson production threshold and the cross section could be directly normalized to the cross section of the pp→ppη reaction, with the η decaying into 3 pions. Since the same final states are selected, the measurement has a low systematical error. The measured cross section ratio σ(pp→ppπ+π−π0)/σ(pp→ppπ0π0π0) is compared to predictions of dominance of different isobars in the intermediate state.

Published
2007

37. LOW-MASS ππ ENHANCEMENT IN BARYONIC ππ PRODUCTION: ABC EFFECT REVISED BY EXCLUSIVE MEASUREMENTS

Author

C. Ekström, R. J. M. Y. Ruber, Magnus Wolke, J. Stepaniak, G. Ivanov, B. Morosov, I. Zartova, P. Thörngren-Engblom, W. Scobel, B. Shwartz, R. Shafigullin, G. J. Wagner, Y. Petukhov, Jozef Zlomanczuk, L. Geren, D. Bogoslowsky, S. Kullander, A. A. Kuznetsov, V. Tchernyshev, W. Oelert, M. Bashkanov, F. Cappellaro, C. Bargholtz, Pawel Marciniewski, A. Povtoreyko, O. Khakimova, E. Jiganov, H. Clement, A. Turowiecki, Leif Gustafsson, Hans Calén, V. Tikhomirov, T. Johansson, Akira Yamamoto, A. Kupść, K. Fransson, T. Skorodko, C. Pauly, A. Schwick, Marek Jacewicz, K. Lindberg, P.-E. Tegnér, R. Meier, I. Koch, Bo Höistad, M. Kaskulov, J. Zabierowski, S. Keleta, V. Sopov, and F. Kren

Subjects
Baryon, Physics, Nuclear physics, Nuclear and High Energy Physics, Complete data, Bound state, Prove it, Astronomy and Astrophysics, Production (computer science), Invariant mass, Low Mass, Atomic and Molecular Physics, and Optics, Spectral line
Abstract

The ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of double-pionic fusion to nuclear bound states - has been investigated since 40 years by inclusive measurements without providing a conclusive interpretation. First exclusive measurements to this topic have now been carried out at CELSIUS-WASA. They confirm a huge ππ threshold enhancement, prove it to be of scalar-isoscalar nature, i.e., a σ-channel phenomenon and reveal the theoretically predicted high-mass enhancement in inclusive spectra to be of πππ rather than of ππ nature - falsifying thus corresponding model predictions for the ABC effect. From the kinematically complete data samples we infer that the interaction between the two Δ particles created in this process is of crucial importance.

Published
2007

38. Measurement of the η→π+π−e+e− decay branching ratio

Author

J. Zabierowski, E. Jiganov, V. Tchernyshev, L. Demiroers, Bo Höistad, P. Thörngren-Engblom, H. Clement, Marek Jacewicz, Wolfgang Scobel, M. Bashkanov, R. Shafigullin, G. J. Wagner, P.-E. Tegnér, H. Pettersson, Karin Schönning, A. A. Kuznetsov, K. Lindberg, W. Oelert, D. Bogoslawsky, A. Turowiecki, Y. Petukhov, Jozef Zlomanczuk, Tord Johansson, V. Sopov, Pawel Marciniewski, V. Tikhomirov, Leif Gustafsson, C. Pauly, R. Meier, Roger Ruber, I. Zartova, Sven Kullander, Akira Yamamoto, L. Geren, I. Koch, T. Skorodko, A. Povtorejko, Chr. Bargholtz, I. V. Laukhin, Hans Calén, Magnus Wolke, Kjell Fransson, Andrzej Kupsc, G. Ivanov, Curt Ekstrom, B. Morosov, B. Shwartz, J. Stepaniak, F. Cappellaro, and S. Negasi Keleta

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Meson, Branching fraction, Detector, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The reaction pd -> He-3 eta at threshold was used to provide a clean source of eta mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay eta -> pi(+)pi( ...

Published
2007

39. From CELSIUS to COSY: on the observation of a dibaryon resonance

Author

T. Skorodko, H. Clement, and M. Bashkanov

Subjects
Physics, Meson, Scattering, Partial wave analysis, Nuclear Theory, FOS: Physical sciences, Resonance, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Nuclear physics, Mass, Mass spectrum, Nuclear fusion, Nuclear Experiment (nucl-ex), Nuclear Experiment, Mathematical Physics, Beam (structure)
Abstract

Using the high-quality beam of storage rings in combination with a pellet target and the hermetic WASA detector covering practically the full solid angle the two-pion production in nucleon-nucleon collisions has been systematically studied by exclusive and kinematically complete measurements -- first at CELSIUS and subsequently at COSY. These measurements resulted in a detailed understanding of the two-pion production mechanism by $t$-channel meson exchange. The investigation of the ABC effect in double-pionic fusion reactions lead the trace to the observation of a narrow dibaryon resonance with $I(J^P) = 0(3^+)$ about 80 MeV below the nominal mass of the conventional $\Delta\Delta$ system. New neutron-proton scattering data, taken with polarized beam at COSY, produce a pole in the coupled $^3D_3$ - $^3G_3$ partial waves at ($2380\pm10~-~i~40\pm5$) MeV establishing thus the first observation of a genuine $s$-channel dibaryon resonance.

Published
2015

40. ABC effect and resonance structure in the double-pionic fusion toHe3

Author

V. Hejny, Akira Yamamoto, A. Kupść, Frank Goldenbaum, A. Khoukaz, Pawel Marciniewski, K. Lalwani, Jozef Zlomanczuk, A. Kuzmin, J. Ritman, V. Serdyuk, P. Żuprański, Jerzy Smyrski, Bo Höistad, M. Berłowski, B. Kamys, P. Wüstner, G. J. Wagner, P. Adlarson, A. Magiera, Hans Calén, F. S. Bergmann, S. Schadmand, R. Varma, S. Sawant, Magnus Wolke, W. Eyrich, A. Zink, K. Pysz, P. Fedorets, M. Bashkanov, P. Goslawski, Kjell Fransson, I. Ozerianska, Ferdous Khan, N. Hüsken, H. Ohm, G. Sterzenbach, D. Pszczel, T. Skorodko, B. Lorentz, P. Podkopał, H. Clement, A. Pyszniak, W. Augustyniak, Alexander Bondar, T. Sefzick, R. Maier, Di. Kirillov, Zbigniew Rudy, M. Żurek, A. Erven, E. Stephan, Ralf Engels, F. Hauenstein, Paweł Moskal, Eryk Czerwiński, T. Johansson, B. Shwartz, J. Stepaniak, M. Mikirtychiants, Magdalena Skurzok, Aleksandra Wrońska, A. Täschner, B. Mariański, Harald Kleines, B. Kłos, E. Perez del Rio, Izabela Ciepał, A. Goswami, A. Pricking, P. Wurm, D. Lersch, H. Ströher, H. P. Morsch, Wojciech Krzemien, W. Erven, Hans Stockhorst, Stanisław Kistryn, E. Doroshkevich, K. Demmich, C.-O. Gullström, Markus Büscher, Marcin Zieliński, N.M. Piskunov, Rolf Stassen, H. Bhatt, Lena Heijkenskjöld, D. Prasuhn, J. Zabierowski, K. Grigoryev, Antoni Szczurek, L. Jarczyk, Günter Kemmerling, K. Föhl, A. Trzciński, P. Kulessa, L. Yurev, V. Sopov, Ankhi Roy, R. Siudak, W. Bardan, and D. Coderre

Subjects
Mass enhancement, Nuclear physics, Physics, Nuclear and High Energy Physics, Fusion, Near threshold, Angular distribution, Meson production, Dalitz plot, Pi interaction, Nuclear matter
Abstract

Exclusive and kinematically complete measurements of the double pionic fusion to He-3 have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhan ...

Published
2015

41. Resonances at COSY — the dibaryon issue

Author

M. Bashkanov, T. Skorodko, and H. Clement

Subjects
Physics, Nuclear physics, Particle physics, QC1-999, Nuclear Theory, Resonance, Nuclear matter, Nuclear Experiment
Abstract

The cooler synchrotron COSY at the research center Julich has been dedicated to the investigation of nucleon-nucleon collisions. Together with appropriate detector setups it has been particularly well suited for the search of resonances in the baryonbaryon system. Hence it is of no surprise that the observation of the first non-trivial dibaryon resonance has been established at this machine. A review on this issue is given - including the quest for dibaryons in nuclear matter.

Published
2015

42. Branching ratios for the decay of d*(2380)

Author

H. Clement, T. Skorodko, and M. Bashkanov

Subjects
Physics, Particle physics, Nuclear and High Energy Physics, дейтроны, Isoscalar, Hadron, Nuclear Theory, FOS: Physical sciences, Branching (polymer chemistry), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Photodisintegration, барионные резонансы, Nuclear fusion, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, адронные распады, Computer Science::Information Theory
Abstract

Based on measurements, the branching ratios for the decay of the recently discovered dibaryon resonance $d^{*}(2380)$ into two-pion production channels and into the np channel are evaluated. Possibilities for a decay into the isoscalar single-pion channel are discussed. Finally, the electromagnetic decay of $d^{*}(2380)$ is considered.

Published
2015

43. Experimental access to Transition Distribution Amplitudes with the P̄ANDA experiment at FAIR

Author

M. C. Mora Espí, Pawel Marciniewski, K. Makonyi, Yupeng Yan, S. Wronka, D. Pietreanu, Shaji Kumar, N. Belikov, D. I. Glazier, A. Gillitzer, K. Khanchai, Ajay Kumar Rai, M. Steinen, D. Calvo, Yury Tikhonov, A. A. Derevschikov, T. A. Pocheptsov, R.A. Salmin, P. Balanutsa, B. J. Liu, P. N. Deepak, A. E. Blinov, S. Lange, S. Ryzhikov, G. Kalicy, Arpit Parmar, P. Musiol, G. D. Alexeev, D. P. Watts, Lennart Isaksson, Tobias Stockmanns, E. Gutz, P. F. Dalpiaz, Zhi Liu, D. Marchand, S. Grieser, A. Gerhardt, D. Kangh, L. Fava, A. A. Festchenko, Harphool Kumawat, I. Zimmermann, M. Albrecht, B. Krusche, A. Sanchez Lorente, E. A. Strokovsky, M. A. Pasyuk, J. Ritman, P. C. Vinodkumar, T. Quagli, M.G. Sapozhnikov, Ashok Kumar, Herbert Koch, V. I. Astakhov, V. Serdyuk, K. M. von Würtemberg, D. Münchow, Hans-Georg Zaunick, S. Marcello, M. Ullrich, A. Mustafa, Paola Gianotti, T. Kuske, Michaela Thiel, Kamal K. Seth, S. Schlimme, C. Schwarz, M. Savrie, B. Ketzer, Jerzy Smyrski, E. Etzelmüller, A. G. Fedunov, H. Sohlbach, K. Malgorzata, Victor Bobrovnikov, R.Sh. Teshev, L. Ayut, V.M. Abazov, B. Spruck, B. Kamys, D. Mülhheim, Krzysztof Swientek, S. Schadmand, M. V. Korzihik, Zbigniew Rudy, Matei Eugen Vasile, T. Wasem, J. Schwiening, D. Lehmann, M. Patsyuk, Karin Schönning, W. Czyzycki, M. Zühlsdorf, V. N. Goryachev, A. G. Zorin, A. Davidenko, W. Lauth, B. Fröhlich, A. Amoroso, V. Lucherini, P. Schakel, Grzegorz Korcyl, G.A. Mustafaev, Smbat Grigoryan, Ajit Kumar Mohanty, Grzegorz Filo, R. Veenstra, P. Wüstner, J. Marton, Boris Batyunya, L. Ferrero, A. N. Skachkova, Edward Lisowski, I. Garzia, D. Bremer, T. Eissner, D. Lin, Y.M. Goncharenko, Soumen Paul, A.A. Efremov, Dipanwita Dutta, Alberto Rotondi, M. Michel, B. Slowinski, A. Arefiev, Philip Woods, I. Augustin, Yan Liang, A. Karavdina, M. Greco, P. Rosier, Antoni Szczurek, N. Saito, K. Föhl, T. Schröder, B. Singh, Mariana Nanova, Andreas Herten, Oleg V. Missevitch, S.A. Zaporozhets, K.-T. Brinkmann, Sukanta Dash, A. Filippi, A. Trzcinski, Marek Idzik, M. O. Distler, J. Schumann, C. Sowa, I. Konorov, J. C. van der Weele, Mathias Fink, A. E. Yakutin, B. Kopf, E. Atomssa, A. Pitka, R. Karabowicz, H. H. Leithoff, Angelo Rivetti, S. Pornrad, S. Diehl, M. Maggiora, B. Kröck, R. Duchat, O. Levitskaya, Gianluigi Boca, Krzysztof Korcyl, Gianangelo Bracco, Harald Kleines, F. Nerling, L. Caldeira Balkeståhl, S. Coli, E. Perevalova, T. Gessler, Klaus Peters, A. Magiera, Vassili Kachanov, M. Hawryluk, S. Ong, R. Varma, X. Shen, T. Czyzewski, M. Domagala, S. Godre, M. Zyzak, J. Pettersson, F. Uhlig, F. De Mori, P.J.J. Lemmens, Alexander D. Vasiliev, Mohammed Al-Turany, Q. Hu, Andrzej Kupsc, R. Schmitz, P. Mahlberg, P. De Remigis, C. Schnier, S. Lusso, R. Dosdall, L. Zotti, J. Van de Wiele, A. Britting, S. Fissum, Zhigang Li, Jozef Zlomanczuk, Amiran Tomaradze, S. Spataro, U. Müller, R. Valente, V. Uzhinsky, Giulio Stancari, G. S. Shabratova, I. Keshelashvili, S. Jowzaee, Harald Merkel, C. Guaraldo, S. Li, Christian Schmidt, M. Steinacher, V. Kozlov, Yu.N. Rogov, A. Bianconi, T. Held, V. Datar, Andrei Fedorov, H. Orth, T. Weber, A. Kozela, Piotr Salabura, M. Destefanis, Andrea Lavagno, M. Kuhlmann, B. Ma, J. Pychy, Piotr Lebiedowicz, L. Capozza, Dominik Kwiatkowski, Andrew Levin, A. Wilms, Germán Mazza, Matthias Richter, Wojciech Krzemien, Sean A Dobbs, J. Pochodzalla, I. Shein, H. Ohm, Paolo Montagna, Paul Alois Buhler, Y. Naryshkin, Hans Calén, A. Apostolou, S. Orfanitski, V. Grishin, A. Kashchuk, V. Kormilitsin, Tomasz Fiutowski, M. Mingnore, M. Krebs, A. Dolgolenko, E. Fioravanti, P.-E. Tegnér, A. Chlopik, A. Gromliuk, Andreas Lehrach, I. Georgadze, B. Czech, B. Zwieglinski, Kurt Hansen, W. Schäfer, C. Motzko, R. Kunne, P. Genova, J. Lühning, A. Psyzniak, S. Bianco, H. Smit, Nicola Bianchi, Felice Iazzi, J. Rieke, M. Fritsch, R. Dzhygadlo, O. Corell, E. Pace, S. I. Manaenkov, V. Chandratre, S. Sosio, A. Olshevskiy, T. Johansson, S. Sanchez, Concettina Sfienti, R. F. Parodi, D. Walther, T. Saito, E. Köhler, Zhi Sun, Markus Büscher, P. Kulessa, Magnus Wolke, I. Kisel, V. Tokmenin, Alexander Vodopyanov, J.H. Zhao, C. Wang, M. Kube, M. Kavatsyuk, T. Hennino, Johann Zmeskal, V. Varentsov, C. Morales Morales, S. Esch, R. Kliemt, G. Schepers, S. Poslavskiy, Alessandro Drago, Dan Pantea, M. Imre, W. Eyrich, D. Melnychuk, M.P. Bussa, Dirk Grunwald, I. Lehmann, D. Rodríguez Piñeiro, Kjell Fransson, A. P. Onuchin, Valery Dormenev, M. Rossbach, F. E. Maas, Giuseppe Giraudo, M. Pelizäus, D. P. Mohanta, H. Deppe, C. Rosenbaum, M. Cardinali, A. G. Denig, A. Boukharov, V. Abramov, A. Hayrapetyan, K. Pysz, Vladimir Blinov, A. K. Hergemöller, A. Ryazantsev, K. Kalita, P. Wintz, Raghunath Sahoo, V. Akishina, P. A. Semenov, V. Balanutsa, Mikael Lundin, M. M. Macri, Anne-Laure Martin, A. Karmokov, U. Cahit, A. Demekhin, G. Rosner, W. Erni, S. Plueger, S. Leiber, Michael Werner, L. Schmitt, S. Costanza, Bent Schröder, R. Arora, D. Deermann, M. Leyhe, S.A. Kononov, S. Belostotski, Ulrich Wiedner, Maria Krawczyk, L. V. Malinina, M. Tiemens, Yu.M. Mel'nik, Ch. Schmidt, O. Merle, U. Thoma, M. Babai, A. Semenov, R. Maier, Ankhi Roy, Michael Düren, L. V. Nogach, E. Widmann, A. Zhadanov, Valentino Rigato, Stanisław Kistryn, P. Fedorets, K. Suzuki, D. A. Morozov, Franco Bradamante, Torbjörn Bäck, L. Busso, C. Le Galliard, Bhavin Patel, Alessandro Bressan, K. Chinorat, M. Wojciechowski, A. Lehmann, A.F. Makarov, A. Galoyan, P. Wieczorek, T. Holtmann, Bernd Voss, Aleksandra Wrońska, J. S. Díaz, M. Hoek, D. Veretennikov, F. H. Heinsius, P. Brandys, F. Balestra, H. Flemming, F. Lisowski, H. Younis, Paweł Moskal, G. Maniscalco, P. Jasinski, V. K. Rodionov, J. G. Messchendorp, R. Schnell, O. Miklukho, D. Prasuhn, M. Zambrana, M. Kümmel, L. Cao, I. Marishev, A. Bersani, Bo Cederwall, K. Götzen, L. Lavezzi, S. Vejdani, N. G. Minaev, Herbert Löhner, V. Metag, R. W. Novotny, E. Tomasi-Gustafsson, N. B. Skachkov, A. Cebulla, Bartosz Mindur, V. Chernetsky, B. Seitz, Daniel M. Kaplan, E. K. Koshurnikov, B. Ramstein, A. Kulkarni, B. J. Roy, T. Sefzick, D. Khaneft, D. Branford, A. A. Piskun, Reinhard Beck, S. Bleser, Yu. Yu. Lobanov, R. Siudak, V. I. Lobanov, E. A. Kravchenko, S. Bukreeva, A. Samartsev, U. Thöring, F. Feldbauer, Ting Xiao, Patrick Achenbach, Hongwei Liu, Johannes Peter Wessels, D. Bettoni, Yu.I. Davydov, V. I. Dormenev, Genady Gavrilov, Ch. Wendel, M. Yu. Barabanov, Kirill M. Semenov-Tian-Shansky, R. Birsa, T. Bel, Günter Kemmerling, A. Khoukaz, V. Carassiti, B. Galnander, Jifeng Hu, M. Bragadireanu, I. A. Kuyanov, Bruce Yabsley, Andrey V. Izotov, O. Noll, J. Kunkel, A. Dbeyssi, K. Suvorov, Vivekanand Jha, Wolfgang Kuhn, Hasko Stenzel, O. Malyshev, A. A. Sokolov, U. Kurilla, G. Kuhl, D. Kaiser, P. Strzempek, A. Goerres, J. Biernat, D. G. Ireland, H. Xu, M. K. Suleimanov, G. Sterzenbach, E. Prencipe, A. Ortiz, N. I. Zhuravlev, A. Täschner, A. Gerasimov, T. Triffterer, M. Deiseroth, A. Wilson, Marek Palka, M. Lindemulder, A. Y. Barnyakov, V.Kh. Dodokhov, D. Nicmorus, Andrey Uzunian, A. Ehret, R. Nellen, Ch. Hammann, M. Steinke, V. L. Malyshev, P. Drexler, Richard Wheadon, A. Cotta Ramusino, P. Sarin, Riccardo Introzzi, H. Clement, I. Kulakov, M. Zuehlsdorf, M. Galuska, S. Kliczewski, G.B. Pontecorvo, D. Przyborowski, Mihai Caprini, V. V. Mochalov, M. Jadhav, M. Mikirtychyants, M. Traxler, Frank Goldenbaum, Research unit Nuclear & Hadron Physics, The PANDA Collaboration, Null, Singh, B. P, Erni, W., Keshelashvili, I., Krusche, B., Steinacher, M., Liu, B., Liu, H., Liu, Z., Shen, X., Wang, C., Zhao, J., Albrecht, M., Fink, M., Heinsius, F. H., Held, T., Holtmann, T., Koch, H., Kopf, B., Kümmel, M., Kuhl, G., Kuhlmann, M., Leyhe, M., Mikirtychyants, M., Musiol, P., Mustafa, A., Pelizäus, M., Pychy, J., Richter, M., Schnier, C., Schröder, T., Sowa, C., Steinke, M., Triffterer, T., Wiedner, U., Beck, R., Hammann, C., Kaiser, D., Ketzer, B., Kube, M., Mahlberg, P., Rossbach, M., Schmidt, C., Schmitz, R., Thoma, U., Walther, D., Wendel, C., Wilson, A., Bianconi, A., Bragadireanu, M., Caprini, M., Pantea, D., Pietreanu, D., Vasile, M. E., Patel, B., Kaplan, D., Brandys, P., Czyzewski, T., Czyzycki, W., Domagala, M., Hawryluk, M., Filo, G., Krawczyk, M., Kwiatkowski, D., Lisowski, E., Lisowski, F., Fiutowski, T., Idzik, M., Mindur, B., Przyborowski, D., Swientek, K., Czech, B., Kliczewski, S., Korcyl, K., Kozela, A., Kulessa, P., Lebiedowicz, P., Malgorzata, K., Pysz, K., Schäfer, W., Siudak, R., Szczurek, A., Biernat, J., Jowzaee, S., Kamys, B., Kistryn, S., Korcyl, G., Krzemien, W., Magiera, A., Moskal, P., Palka, M., Psyzniak, A., Rudy, Z., Salabura, P., Smyrski, J., Strzempek, P., Wrońska, A., Augustin, I., Lehmann, I., Nicmorus, D., Schepers, G., Schmitt, L., Al Turany, M., Cahit, U., Capozza, L., Dbeyssi, A., Deppe, H., Dzhygadlo, R., Ehret, A., Flemming, H., Gerhardt, A., Götzen, K., Karabowicz, R., Kliemt, R., Kunkel, J., Kurilla, U., Lehmann, D., Lühning, J., Maas, F., Morales Morales, C., Mora Espí, M. C., Nerling, F., Orth, H., Peters, K., Rodríguez Piñeiro, D., Saito, N., Saito, T., Sánchez Lorente, A., Schmidt, C. J., Schwarz, C., Schwiening, J., Traxler, M., Valente, R., Voss, B., Wieczorek, P., Wilms, A., Zühlsdorf, M., Abazov, V. M., Alexeev, G., Arefiev, A., Astakhov, V. I., Barabanov, M. Y. u., Batyunya, B. V., Davydov, Y. u. I., Dodokhov, V. K. h., Efremov, A. A., Fedunov, A. G., Festchenko, A. A., Galoyan, A. S., Grigoryan, S., Karmokov, A., Koshurnikov, E. K., Lobanov, V. I., Lobanov, Y. u. Y. u., Makarov, A. F., Malinina, L. V., Malyshev, V. L., Mustafaev, G. A., Olshevskiy, A., Pasyuk, M. A., Perevalova, E. A., Piskun, A. A., Pocheptsov, T. A., Pontecorvo, G., Rodionov, V. K., Rogov, Y. u. N., Salmin, R. A., Samartsev, A. G., Sapozhnikov, M. G., Shabratova, G. S., Skachkov, N. B., Skachkova, A. N., Strokovsky, E. A., Suleimanov, M. K., Teshev, R. S. h., Tokmenin, V. V., Uzhinsky, V. V., Vodopyanov, A. S., Zaporozhets, S. A., Zhuravlev, N. I., Zorin, A. G., Branford, D., Glazier, D., Watts, D., Woods, P., Britting, A., Eyrich, W., Lehmann, A., Uhlig, F., Dobbs, S., Seth, K., Tomaradze, A., Xiao, T., Bettoni, D., Carassiti, V., Cotta Ramusino, A., Dalpiaz, P., Drago, A., Fioravanti, E., Garzia, I., Savriè, M., Stancari, G., Akishina, V., Kisel, I., Kulakov, I., Zyzak, M., Arora, R., Bel, T., Gromliuk, A., Kalicy, G., Krebs, M., Patsyuk, M., Zuehlsdorf, M., Bianchi, N., Gianotti, P., Guaraldo, C., Lucherini, V., Pace, E., Bersani, A., Bracco, G., Macri, M., Parodi, R. F., Bianco, S., Bremer, D., Brinkmann, K. T., Diehl, S., Dormenev, V., Drexler, P., Düren, M., Eissner, T., Etzelmüller, E., Föhl, K., Galuska, M., Gessler, T., Gutz, E., Hayrapetyan, A., Hu, J., Kröck, B., Kühn, W., Kuske, T., Lange, S., Liang, Y., Merle, O., Metag, V., Mülhheim, D., Münchow, D., Nanova, M., Novotny, R., Pitka, A., Quagli, T., Rieke, J., Rosenbaum, C., Schnell, R., Spruck, B., Stenzel, H., Thöring, U., Ullrich, M., Wasem, T., Werner, M., Zaunick, H. G., Ireland, D., Rosner, G., Seitz, B., Deepak, P. N., Kulkarni, A. V., Apostolou, A., Babai, M., Kavatsyuk, M., Lemmens, P., Lindemulder, M., Löhner, H., Messchendorp, J., Schakel, P., Smit, H., van der Weele, J. C., Tiemens, M., Veenstra, R., Vejdani, S., Kalita, K., Mohanta, D. P., Kumar, A., Roy, A., Sahoo, R., Sohlbach, H., Büscher, M., Cao, L., Cebulla, A., Deermann, D., Dosdall, R., Esch, S., Georgadze, I., Gillitzer, A., Goerres, A., Goldenbaum, F., Grunwald, D., Herten, A., Hu, Q., Kemmerling, G., Kleines, H., Kozlov, V., Lehrach, A., Leiber, S., Maier, R., Nellen, R., Ohm, H., Orfanitski, S., Prasuhn, D., Prencipe, E., Ritman, J., Schadmand, S., Schumann, J., Sefzick, T., Serdyuk, V., Sterzenbach, G., Stockmanns, T., Wintz, P., Wüstner, P., Xu, H., Li, S., Li, Z., Sun, Z., Rigato, V., Fissum, S., Hansen, K., Isaksson, L., Lundin, M., Schröder, B., Achenbach, P., Bleser, S., Cardinali, M., Corell, O., Deiseroth, M., Denig, A., Distler, M., Feldbauer, F., Fritsch, M., Jasinski, P., Hoek, M., Kangh, D., Karavdina, A., Lauth, W., Leithoff, H., Merkel, H., Michel, M., Motzko, C., Müller, U., Noll, O., Plueger, S., Pochodzalla, J., Sanchez, S., Schlimme, S., Sfienti, C., Steinen, M., Thiel, M., Weber, T., Zambrana, M., Dormenev, V. I., Fedorov, A. A., Korzihik, M. V., Missevitch, O. V., Balanutsa, P., Balanutsa, V., Chernetsky, V., Demekhin, A., Dolgolenko, A., Fedorets, P., Gerasimov, A., Goryachev, V., Varentsov, V., Boukharov, A., Malyshev, O., Marishev, I., Semenov, A., Konorov, I., Paul, S., Grieser, S., Hergemöller, A. K., Khoukaz, A., Köhler, E., Täschner, A., Wessels, J., Dash, S., Jadhav, M., Kumar, S., Sarin, P., Varma, R., Chandratre, V. B., Datar, V., Dutta, D., Jha, V., Kumawat, H., Mohanty, A. K., Roy, B., Yan, Y., Chinorat, K., Khanchai, K., Ayut, L., Pornrad, S., Barnyakov, A. Y., Blinov, A. E., Blinov, V. E., Bobrovnikov, V. S., Kononov, S. A., Kravchenko, E. A., Kuyanov, I. A., Onuchin, A. P., Sokolov, A. A., Tikhonov, Y. A., Atomssa, E., Hennino, T., Imre, M., Kunne, R., Le Galliard, C., Ma, B., Marchand, D., Ong, S., Ramstein, B., Rosier, P., Tomasi Gustafsson, E., Van de Wiele, J., Boca, G., Costanza, S., Genova, P., Lavezzi, L., Montagna, P., Rotondi, A., Abramov, V., Belikov, N., Bukreeva, S., Davidenko, A., Derevschikov, A., Goncharenko, Y., Grishin, V., Kachanov, V., Kormilitsin, V., Melnik, Y., Levin, A., Minaev, N., Mochalov, V., Morozov, D., Nogach, L., Poslavskiy, S., Ryazantsev, A., Ryzhikov, S., Semenov, P., Shein, I., Uzunian, A., Vasiliev, A., Yakutin, A., Yabsley, B., Bäck, T., Cederwall, B., Makónyi, K., Tegnér, P. E., von Würtemberg, K. M., Belostotski, S., Gavrilov, G., Izotov, A., Kashchuk, A., Levitskaya, O., Manaenkov, S., Miklukho, O., Naryshkin, Y., Suvorov, K., Veretennikov, D., Zhadanov, A., Rai, A. K., Godre, S. S., Duchat, R., Amoroso, A., Bussa, M. P., Busso, L., De Mori, F., Destefanis, M., Fava, L., Ferrero, L., Greco, M., Maggiora, M., Maniscalco, G., Marcello, S., Sosio, S., Spataro, S., Zotti, L., Calvo, D., Coli, S., De Remigis, P., Filippi, A., Giraudo, G., Lusso, S., Mazza, G., Mingnore, M., Rivetti, A., Wheadon, R., Balestra, F., Iazzi, F., Introzzi, R., Lavagno, A., Younis, H., Birsa, Renato, Bradamante, Franco, Bressan, Andrea, Martin, Anna, Clement, H., Gålnander, B., Caldeira Balkeståhl, L., Calén, H., Fransson, K., Johansson, T., Kupsc, A., Marciniewski, P., Pettersson, J., Schönning, K., Wolke, M., Zlomanczuk, J., Díaz, J., Ortiz, A., Vinodkumar, P. C., Parmar, A., Chlopik, A., Melnychuk, D., Slowinski, B., Trzcinski, A., Wojciechowski, M., Wronka, S., Zwieglinski, B., Bühler, P., Marton, J., Suzuki, K., Widmann, E., Zmeskal, J., Fröhlich, B., Khaneft, D., Lin, D., Zimmermann, I., and Semenov Tian Shansky, K.

Subjects
Particle physics, (P)Over-Baranda, Nuclear and High Energy Physics, Electroproduction, Hadron, Annihilation, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, Particle identification, Nucleon, NO, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Factorization, 0103 physical sciences, Fysik, Invariant mass, ddc:530, Meson Production, Monte-Carlo, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Quantum chromodynamics, 010308 nuclear & particles physics, Perturbative QCD, Qcd, Physical Sciences, Exclusive Processes, High Energy Physics::Experiment, Pi(0), Cross-Sections, Energy (signal processing)
Abstract

Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion ($��N$) TDAs from $\bar{p}p \to e^+e^- ��^0$ reaction with the future PANDA detector at the FAIR facility. At high center of mass energy and high invariant mass squared of the lepton pair $q^2$, the amplitude of the signal channel $\bar{p}p \to e^+e^- ��^0$ admits a QCD factorized description in terms of $��N$ TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring $\bar{p}p \to e^+e^- ��^0$ with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. $\bar{p}p \to ��^+��^- ��^0$ were performed for the center of mass energy squared $s = 5$ GeV$^2$ and $s = 10$ GeV$^2$, in the kinematic regions $3.0 < q^2 < 4.3$ GeV$^2$ and $5 < q^2 < 9$ GeV$^2$, respectively, with a neutral pion scattered in the forward or backward cone $| \cos��_{��^0}| > 0.5 $ in the proton-antiproton center of mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of $5\cdot 10^7$ ($1\cdot 10^7$) at low (high) $q^2$ for $s=5$ GeV$^2$, and of $1\cdot 10^8$ ($6\cdot 10^6$) at low (high) $q^2$ for $s=10$ GeV$^2$, while keeping the signal reconstruction efficiency at around $40\%$. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to $2$ fb$^{-1}$ of integrated luminosity. (.../...), 19 pages, 7 figures (some multiple), 2 tables (each double), preprint of an article for epj - v2

Published
2015

44. Extracting the depolarization coefficient D_NN from data measured with a full acceptance detector

Author

James Ritman, F. Hauenstein, A. Gillitzer, R. Dzhygadlo, E. Roderburg, P. Wintz, H. Clement, D. Grzonka, M. Röder, W. Eyrich, and S. Jowzaee

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, Detector, Hyperon, Strangeness production, FOS: Physical sciences, Depolarization, Polarization (waves), 01 natural sciences, Nuclear physics, Hadron physics, 0103 physical sciences, Hermetic detector, Spin transfer, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Instrumentation
Abstract

The spin transfer from vertically polarized beam protons to Lambda or Sigma hyperons of the associated strangeness production pp -> pK Lambda (Sigma) is described with the depolarization coefficient D_NN. As the polarization of the hyperons is determined by their weak decays, detectors, which have a large acceptance for the decay particles, are needed. In this paper a formula is derived, which describes the depolarization coefficient D_NN by count rates of a 4 pi detector. It is shown, that formulas, which are given in publications for detectors with restricted acceptance, are specific cases of this formula for a 4 pi detector., Accepted for publication by Nuclear Instruments and Methods in Physics Research Section A

Published
2015
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45. Study of spectator tagging in the reaction np → ppπwith a deuteron beam

Author

M. Schulte-Wissermann, L. Naumann, A. Ucar, A. Erhardt, H. P. Morsch, N. Paul, P. Wintz, H. Clement, C. Pizzolotto, K. Kilian, René Jäkel, G. Y. Sun, E. Kuhlmann, H. Freiesleben, W. Schroeder, A. Teufel, P. Wüstner, K. Möller, P. Zupranski, M. Abdel-Bary, L. Karsch, K.-Th. Brinkmann, E. Doroshkevich, P. Schönmeier, E. Roderburg, J. Ritman, Marc Wagner, A. Gillitzer, S. Dshemuchadse, G. J. Wagner, and W. Eyrich

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, Nuclear Theory, Hadron, Monte Carlo method, Nuclear physics, Momentum, Deuterium, Nuclear fusion, Neutron, Nuclear Experiment, Wave function
Abstract

The reaction \(dp \ensuremath \rightarrow ppp \pi^-\) has been studied in a kinematically complete experiment at a single beam momentum \(\ensuremath p_{d}=1.85\)GeV/c (T = 759MeV). All four ejectiles have been detected in the large-acceptance time-of-flight spectrometer COSY-TOF. We analyzed the data along the lines of the spectator model as a means to isolate the quasi-free \(\ensuremath np\rightarrow pp\pi^-\) reaction. The spectator proton was identified by its momentum and flight direction thus yielding access to the associated Fermi motion of the bound neutron. A comparison is carried out with Monte Carlo simulations based on two different parameterizations of the deuteron wave function. Up to a Fermi momentum of roughly 150MeV/c no significant deviations between experimental and simulated data of various observables were found from which we conclude that the deuteron can indeed be taken as a valid substitute for the neutron.

Published
2006

46. Exclusive measurements of pd→He3ππ: The ABC effect revisited

Author

Akira Yamamoto, K. Fransson, S. Kullander, F. Cappellaro, A. Turowiecki, Pawel Marciniewski, V. Tikhomirov, O. Khakimova, E. Jiganov, Leif Gustafsson, H. Clement, D. Bogoslawsky, A. Povtorejko, Jozef Zlomanczuk, P. Thörngren-Engblom, C. Ekström, Hans Calén, W. Scobel, C. Pauly, G. Ivanov, I. Koch, R. J. M. Y. Ruber, Magnus Wolke, B. Morosov, A. Kupść, T. Johansson, M. Bashkanov, B. Shwartz, J. Stepaniak, Y. Petukho, M. Kaskulov, V. Sopov, F. Kren, G. J. Wagner, J. Zabierowski, Marek Jacewicz, V. Tchernyshev, J. Greiff, L. Demiroers, R. Meier, A. A. Kuznetsov, W. Oelert, Bo Höistad, T. Skorodko, and S. Keleta

Subjects
Mass enhancement, Nuclear physics, Physics, Nuclear and High Energy Physics, Angular distribution, Isoscalar, Dalitz plot, Atomic physics, Storage ring
Abstract

Exclusive measurements of the reactions p d → He 3 π + π − and p d → He 3 π 0 π 0 have been carried out at T p = 0.893 GeV at the CELSIUS storage ring using the WASA detector. The π + π − channel evidences a pronounced enhancement at low invariant ππ masses—as anticipated from previous inclusive measurements of the ABC effect. This enhancement is seen to be even much larger in the isoscalar π 0 π 0 channel. The differential distributions prove this enhancement to be of scalar–isoscalar nature. ΔΔ calculations give a good description of the data, if a boundstate condition is imposed for the intermediate ΔΔ system.

Published
2006

47. Hyperon production in the channel pp→K+Λp near the reaction threshold

Author

A. Böhm, G. Y. Sun, U. Zielinski, D. Hesselbarth, S. Marwinski, M. Steinke, G. J. Wagner, A. Wilms, J. Hauffe, R. Geyer, W. Eyrich, H. Freiesleben, P. Herrmann, A. Hassan, F. Stinzing, M. Schulte-Wissermann, A. Metzger, W. Schroeder, Herbert Koch, C. Fanara, S. Marcello, S. Dshemuchadse, K. Möller, Peter Michel, K. Kilian, A. Filippi, M. Fritsch, J. Wächter, Marc Wagner, H. Clement, J. Kress, A. Schamlott, S. Abd El-Samad, K.-Th. Brinkmann, R. Bilger, S. Wirth, B. Jakob, L. Naumann, E. Roderburg, H. P. Morsch, A. Erhardt, E. Kuhlmann, and P. Schönmeier

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Angular distribution, Spectrometer, Hyperon, Dalitz plot, Resonance, Production (computer science), Observable, Atomic physics, Beam (structure)
Abstract

Hyperon production in the threshold region was studied in the reaction pp → K + Λ p using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at three different beam momenta p beam = 2.59 , 2.68 and 2.85 GeV/ c (corresponding to excess energies of ɛ = 85 , 115 and 171 MeV). Total cross-sections were deduced to be 7.4 ± 0.5 μb , 8.6 ± 0.6 μb and 16.5 ± 0.4 μb , respectively. Differential observables including Dalitz plots were obtained. From the investigation of the Dalitz plot at p beam = 2.85 GeV / c a dominant contribution of the N ∗ ( 1650 ) -resonance to the reaction mechanism was found. In addition the pΛ -final-state interaction turned out to have a significant influence on the Dalitz plot distribution even 171 MeV above threshold.

Published
2006

48. TWO-PION PRODUCTION, γγ LINE AND ASPECTS OF σ MESON, BOSE–EINSTEIN CORRELATIONS AND ISOSPIN BREAKING

Author

T. Johansson, D. Bogoslawsky, Jozef Zlomanczuk, C. Ekström, Akira Yamamoto, A. Kupść, E. Jiganov, P. Thörngren Engblom, G. J. Wagner, H. Clement, O. Khakimova, K. Fransson, W. Oelert, Leif Gustafsson, E. Doroshkevich, S. Kullander, G. Ivanov, Marek Jacewicz, J. Zabierowski, R. Meier, T. Skorodko, S. Keleta, F. Cappellano, L. Demiroers, V. Tchernyshev, Bo Höistad, M. Kaskulov, V. Sopov, F. Kren, C. Pauly, J. Greiff, A. N. Kuznetsov, B. Morosow, Pawel Marciniewski, R. J. M. Y. Ruber, I. Koch, Hans Calén, M. Bashkanov, Ulrich Wiedner, W. Scobel, A. Turowiecki, Magnus Wolke, V. Tikhomirov, J. Stepaniak, Y. Petukhov, B.A. Shwartz, and A. Povtorejko

Subjects
Physics, Nuclear and High Energy Physics, Roper resonance, Particle physics, Hydrogen, Meson, chemistry.chemical_element, Astronomy and Astrophysics, Bose–Einstein correlations, Invariant (physics), Atomic and Molecular Physics, and Optics, Nuclear physics, Pion, chemistry, Isospin, Hermetic detector
Abstract

The pp→ppx(x=γγ, π0π0, π+π-) reactions have been measured at CELSIUS in the energy range Tp=775-1360 MeV using the WASA 4π detector with hydrogen pellet target. Close to threshold the ppπ+π- data are in accordance with the Roper resonance concept and/or a dynamic formation of the σ meson. At higher energies the formation of the ΔΔ system becomes increasingly dominant. The ppπ0π0 channel basically shows similar features, however, develops a peculiar enhancement at small invariant masses Mπ0π0 - in resemblance of Bose-Einstein correlations. Alternatively, the enhancement could be also indicative of a (dynamic) isospin breaking due to ππ rescattering in the σ channel. The latter is favored by the results on pd→3 He x (x=π0π0, π+π-), where the observed π0π0 enhancements are still much larger. In the γγ channel a line at Mγγ=2mπ is observed. The possible nature of this line is discussed.

Published
2005

49. PION-NUCLEON SCATTERING EXPERIMENTS AT LOW ENERGIES: π-p→π0n TOTAL CROSS SECTIONS

Author

H. Denz, E. Friedman, G. J. Wagner, H. Clement, E. F. Gibson, J. Breitschopf, R. Meier, M. Cröni, and M. Bauer

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Explicit symmetry breaking, Particle physics, Pion, Scattering, Spontaneous symmetry breaking, Astronomy and Astrophysics, Nucleon, Chiral symmetry breaking, Atomic and Molecular Physics, and Optics, Charge exchange
Abstract

Total cross sections of the single charge exchange reaction π-p→π0n have been measured at PSI from about 40 to 250 MeV using a transmission technique. Preliminary results show an excellent agreement with predictions from the SAID FA02 phase shift analysis for energies above 70 MeV.

Published
2005

50. VECTOR MESON PRODUCTION IN COLLISIONS OF NUCLEONS

Author

G. J. Wagner, P. Michel, Jens-Christoph Georgi, L. Naumann, L. Pizzolotto, H. Dutz, H. Koch, L. Pinna, J. Kreß, H. Freiesleben, Marc Wagner, E. Roderburg, A. Erhardt, A. Schamlott, M. Schulte-Wissermann, W. Ullrich, S. Dshemuchadse, René Jäkel, S. Marcello, P. Gonser, K. Kilian, M. Steinke, A. Ucar, H. P. Morsch, F. Stinzing, K.-Th. Brinkmann, M. Fritsch, W. Schroeder, G. Y. Sun, P. Zupranski, S. Wirth, K. Ehrhardt, L. Karsch, K. Möller, A. Filippi, E. Kuhlmann, W. Meyer, A. Gillitzer, E. Doroshkevich, W. Eyrich, M. Abdel-Bary, T. Sefzick, S. Abdel-Samad, P. Wintz, H. Clement, A. Wilms, H. Mörtel, P. Wüstner, and P. Schönmeier

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, Spectrometer, proton-proton collisions, vector mesons, hadron physics, Nuclear Theory, Astronomy and Astrophysics, vector meson production, reaction mechanism and resonances, Atomic and Molecular Physics, and Optics, Baryon, Nuclear physics, Formalism (philosophy of mathematics), Hadron physics, Vector meson, Nuclear Experiment, Nucleon, Nucleon-nucleon interaction
Abstract

The production of vector mesons in collisions between nucleons is studied in order to address a variety of issues concerning nucleon-nucleon interaction, reaction mechanism and properties of baryons. These studies are summarized with emphasis on the most recent experiments at the Time-of-Flight spectrometer TOF and results obtained at the COoler SYnchrotron COSY in Jülich. While currently the open questions regarding the so-called OZI violation, its relation to the meson exchange picture and the relative importance of contributions to the production mechanism from various channels within this formalism are still unresolved, the present-day experiments hold the potential to clarify the situation greatly. Possible extensions of the experimental program on vector mesons using 4π detection techniques for charged as well as neutral particles, in particular π0, are discussed.

Published
2005

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