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74 results on '"Hans Stockhorst"'

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. 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

4. Search for C violation in the decay η → π0e+e− with WASA-at-COSY

Author

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

Subjects
Nuclear and High Energy Physics, Meson, Hadron, Elementary particle, cząstki elementarne, 01 natural sciences, Standard Model, fizyka jądrowa, бозоны, Pion, 0103 physical sciences, Intermediate state, detektor WASA, ddc:530, Nuclear Experiment, 010306 general physics, Boson, Physics, 010308 nuclear & particles physics, фотоны, распад, respiratory system, lcsh:QC1-999, 3. Good health, детекторы, cardiovascular system, мезоны, Physical chemistry, High Energy Physics::Experiment, Radioactive decay, lcsh:Physics, circulatory and respiratory physiology
Abstract

We report on the search for the rare decay η → π 0 e + e − which is of interest to study C violation in the electromagnetic interaction which would indicate contributions from physics beyond the Standard Model, since the allowed decay via a two-photon intermediate state is strongly suppressed. The experiment has been performed using the WASA-at-COSY installation, located at the COSY accelerator of the Forschungszentrum Julich, Germany. In total 3 × 10 7 events of the reaction p d → 3 He η have been recorded at an excess energy of Q = 59.8 MeV . Based on this data set the C parity violating decay η → π 0 γ ⁎ → π 0 e + e − via a single-photon intermediate state has been searched for, resulting in new upper limits of Γ ( η → π 0 e + e − ) / Γ ( η → π + π − π 0 ) 3.28 × 10 − 5 and Γ ( η → π 0 e + e − ) / Γ ( η → all ) 7.5 × 10 − 6 ( CL = 90 % ), respectively.

Published
2018

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. 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

8. 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

9. 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

10. 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

11. 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

12. Effect of electron beam cooling on transversal and longitudinal emittance of an external proton beam

Author

Hans Stockhorst, P. von Rossen, R. Siudak, A. Magiera, H. J. Stein, D. Prasuhn, K. Kilian, and Hartmut Machner

Subjects
Physics, Nuclear and High Energy Physics, emittance, Proton, business.industry, charged particle beam, Physik (inkl. Astronomie), law.invention, Ion, Momentum, Optics, law, Cathode ray, Physics::Accelerator Physics, Thermal emittance, eectron cooling, Physics::Atomic Physics, Atomic physics, business, Charged particle beam, Instrumentation, Beam (structure), Electron cooling
Abstract

Benefits of electron cooling to the quality of extracted ion beams from storage rings are discussed. The transversal emittances of an external proton beam with and without electron cooling at injection energy are measured with the GEM detector assembly. While the horizontal emittance remains the vertical emittance shrinks by the cooling process. The longitudinal momentum variance is also reduced by cooling.

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. New experimental upper limit of the electron–proton spin-flip cross-section

Author

G. Ciullo, G. Guidoboni, Alexander Smirnov, H. Seyfarth, H. Stro¨her, D. Prasuhn, R. Schleichert, G. Macharashvili, P. Tho¨rngren Engblom, Alexander D. Vasiliev, S. Bertelli, B. Lorentz, Y. Valdau, Ulf Bechstedt, D. Chiladze, A. I. Kulikov, G. Tagliente, S.V. Trusov, M. Mikirtychiants, Ralf Engels, M. D. Tabidze, A.K. Kacharava, P. Goslawski, M. Contalbrigo, S. Mikirtychiants, M. Papenbrock, R. Maier, S. Dymov, D. Oellers, Igor Meshkov, P. Lenisa, L. Barion, Hans Stockhorst, P. Zupranski, M. S. Nioradze, M. Statera, B. Mariański, N.L. Lomidze, P. F. Dalpiaz, Z. Bagdasarian, S. Merzliakov, A. Trzciński, Harald Kleines, M. Gaisser, A. Pesce, S. Barsov, P. Wüstner, S. Martin, Ralf Gebel, E. Steffens, Frank Rathmann, G. Langenberg, A. Khoukaz, H. J. Stein, V. Carassiti, D. Mchedlishvili, M. Mielke, Luciano Pappalardo, J. Sarkadi, A. Nass, H. O. Meyer, Andreas Lehrach, Nikolai N. Nikolaev, C. Weidemann, W. Augustyniak, and K. Grigoriev

Subjects
Nuclear and High Energy Physics, Polarized beams, Proton, 29.27.Hj Polarized beams, Elementary particle, Antiprotons, Electron, 29.25.Pj Polarized and other targets, 01 natural sciences, Electron-proton scattering, Storage rings, PACS 29.25 Particle sources and targets: preparation and technology, 29.27.Ac Beam injection and extraction, 0103 physical sciences, Proton spin crisis, Fysik, 010306 general physics, Instrumentation, Spin-½, Physics, 010308 nuclear & particles physics, Antiproton, Physical Sciences, Physics::Accelerator Physics, Atomic physics, Nucleon, Beam (structure)
Abstract

In a previous publication, measurements of the depolarization of a stored proton beam by interaction with a co-propagating unpolarized electron beam at low relative energy have been presented and an upper limit of about 3 x 10(7) b for the electron-proton spin flip cross-section was determined. A refined analysis presented in this paper reduces the previous upper limit by a factor of three by the introduction of a new procedure that, also makes use of non-identified particles. QC 20140806

Published
2014

16. Measurements of branching ratios for η decays into charged particles

Author

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

Subjects
Energy loss, Particle physics, Meson, Dalitz plot, Branching (polymer chemistry), 01 natural sciences, Subatomär fysik, Conversion Decays, Subatomic Physics, 0103 physical sciences, ddc:530, Gamma, Transition Form-Factors, Nuclear Experiment, 010306 general physics, Na60, Physics, Omega, 010308 nuclear & particles physics, Branching fraction, High Energy Physics::Phenomenology, Detector, Mu(+)Mu(-)Gamma, Charged particle, Crystallography, High Energy Physics::Experiment
Abstract

The WASA-at-COSY experiment has collected $3\ifmmode\times\else\texttimes\fi{}{10}^{7}$ events with $\ensuremath{\eta}$ mesons produced via the reaction $pd\ensuremath{\rightarrow}^{3}\mathrm{He}\phantom{\rule{0.16em}{0ex}}\ensuremath{\eta}$ at $\mathrm{T}=1.0\phantom{\rule{4pt}{0ex}}\mathrm{GeV}$. Using this data set, we evaluate the branching ratios of the decays $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\gamma}$, $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$, $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$, and $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$. The branching ratios are normalized to the $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decay. In addition an upper limit on a $CP$-violating asymmetry in $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$ is extracted.

Published
2016

17. 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

18. Excitation of the Δ(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV

Author

S.V. Trusov, P. Goslawski, S. Barsov, Andreas Lehrach, Hans Stockhorst, M. Mielke, V. Kamerdzhiev, R. Maier, G.G. Macharashvili, H. Seyfarth, M. D. Tabidze, A. Khoukaz, H. J. Stein, A.K. Kacharava, M. S. Nioradze, M. Mikirtychyants, H. Ströher, I. Keshelashvili, O. Imambekov, M. Papenbrock, M. Hartmann, J. Carbonell, B. Lorentz, S. Dymov, Ralf Engels, A. Dzyuba, V. V. Glagolev, D. Mchedlishvili, E. Steffens, V. Serdyuk, A. I. Kulikov, K. Grigoryev, D. Prasuhn, P. Kulessa, Yu. Valdau, S. Merzliakov, Yu. N. Uzikov, Colin Wilkin, V.I. Komarov, D. Chiladze, N.L. Lomidze, S. Mikirtychyants, H. Ohm, Frank Rathmann, and Ralf Gebel

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Momentum transfer, 01 natural sciences, Nuclear physics, Pion, Deuterium, 0103 physical sciences, Isobar, Invariant mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Excitation
Abstract

The charge-exchange break-up of polarised deuterons d → p → { p p } s n , where the final { p p } s diproton system has a very low excitation energy and hence is mainly in the S 0 1 state, is a powerful tool to probe the spin-flip terms in the proton–neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the Δ ( 1232 ) isobar in the d → p → { p p } s X reaction. Values of the differential cross section and two deuteron tensor analysing powers, A x x and A y y , have been extracted as functions of the momentum transfer to the diproton or the invariant mass M X of the unobserved system X. The unpolarised cross section in the high M X region is well described in a model that includes only direct excitation of the Δ isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low M X , even when Δ excitation in the projectile deuteron is included in the calculation. Furthermore, direct Δ production through one pion exchange only reproduces the angular dependence of the difference between the two tensor analysing powers.

Published
2013

19. Polarization of a stored beam by spin-filtering

Author

M. S. Nioradze, Andreas Lehrach, M. Papenbrock, M. Statera, A. Trzciński, A. Khoukaz, H. J. Stein, V. Carassiti, P. Wüstner, M. D. Tabidze, M. Nekipelov, B. Mariański, G.G. Macharashvili, P. F. Dalpiaz, H. Straatman, B. Lorentz, H. O. Meyer, Ulf Bechstedt, G. Guidoboni, S.V. Trusov, S. Martin, Alexander D. Vasiliev, E. Steffens, Paolo Lenisa, Nikolai N. Nikolaev, A. Pesce, M. Mielke, D. Mchedlishvili, M. Gaisser, S. Bertelli, S. Dymov, S. Mikirtychiants, L. Barion, Massimiliano Fiorini, G. Ciullo, M. Contalbrigo, Ralf Gebel, V. Shmakova, P. Thörngren-Engblom, Luciano Pappalardo, A. Smirnov, A. Polyanskiy, M. Mikirtychiants, R. Maier, S. Barsov, Yu. Valdau, Hans Stockhorst, P. Zupranski, D. Chiladze, W. Augustyniak, D. Oellers, C. Weidemann, H. Seyfarth, A. Nass, I.N. Meshkov, Frank Rathmann, G. Langenberg, K. M. von Würtemberg, H. Ströher, S. Merzliakov, A. I. Kulikov, N.L. Lomidze, G. Tagliente, A.K. Kacharava, P. Benati, W. Erwen, J. Sarkadi, Harald Kleines, K. Grigoriev, P. Goslaswski, R. Engels, and D. Prasuhn

Subjects
Physics, Nuclear and High Energy Physics, Spin filtering, Polarized beams, 29.27.Hj Polarized beams, 29.20.D- Cyclic accelerators and storage rings, Antiprotons, 010308 nuclear & particles physics, Nuclear Theory, Physics::Data Analysis, Statistics and Probability, Polarization (waves), 01 natural sciences, Storage rings, Nuclear physics, Antiproton, Physical Sciences, 0103 physical sciences, Physics::Accelerator Physics, Fysik, Condensed Matter::Strongly Correlated Electrons, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, that compares well with the theoretical prediction from the nucleon-nucleon potential. The test confirms that spin-filtering can be adopted as a method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons. (C) 2012 Elsevier B.V. All rights reserved.

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. BEAM DYNAMICS OF THE HIGH-ENERGY STORAGE RING (HESR) FOR FAIR

Author

Hans Stockhorst, D. Welsch, Bernd Lorentz, Andreas Lehrach, R. Tölle, K. Bongardt, R. Maier, and D. Prasuhn

Subjects
Physics, Nuclear and High Energy Physics, Luminosity (scattering theory), General Physics and Astronomy, law.invention, Nuclear physics, Momentum, law, Antiproton, Stochastic cooling, Facility for Antiproton and Ion Research, Beam (structure), Storage ring, Electron cooling
Abstract

The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton storage ring in the momentum range from 1.5 to 15 GeV/c.1,2 The HESR is being designed and built by a consortium consisting of IKP at Forschungszentrum Jülich, TSL at Uppsala University, and GSI Darmstadt. An important feature of this new facility is the combination of phase-space cooled beams and thick internal targets (e.g. pellet targets) which results in demanding beam parameter requirements for two operation modes: high luminosity mode with peak luminosities of up to 2 · 1032 cm -2 s -1 and high resolution mode with a relative momentum spread in the order of a few times 10-5. To reach these beam parameters one needs a very powerful phase-space cooling utilizing high-energy electron cooling and high-bandwidth stochastic cooling. In this paper different beam dynamics issues like closed orbit correction, performance of cooled beams interacting with internal targets and luminosity considerations are discussed.

Published
2009

23. 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

24. Instability phenomena of electron-cooled ion beams at COSY

Author

Igor Meshkov, I. Mohos, Hans Stockhorst, V. Kamerdzhiev, D. Prasuhn, H. J. Stein, J. Dietrich, A. Sidorin, and R. Maier

Subjects
Physics, Nuclear and High Energy Physics, Electron, Instability, Synchrotron, law.invention, Ion, Transverse plane, law, Physics::Accelerator Physics, Landau damping, Atomic physics, Instrumentation, Beam (structure), Electron cooling
Abstract

At the cooler synchrotron COSY electron cooling is used after stripping injection of H− or D− ions in order to prepare phase-space-dense ion beams before acceleration to a requested energy. The electron-cooled beam has been successfully applied for specific external experiments. In addition, stacking of an electron cooled beam at injection could significantly increase the stored beam intensity. Transverse coherent instabilities due to beam–wall interaction occurring at higher intensities could be cured through chromaticity correction either by introducing more Landau damping or by applying an active transverse feedback system. This led to an increase in intensity and stability of a cooled beam.

Published
2004

25. Measurement of theη→π+π−π0Dalitz plot distribution

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Distribution (number theory), Meson, 010308 nuclear & particles physics, 0103 physical sciences, Dalitz plot, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, 01 natural sciences
Abstract

The Dalitz plot distribution of the $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decay is determined by using a data sample of $1.2\ifmmode\times\else\texttimes\fi{}{10}^{7}$ $\ensuremath{\eta}$ mesons from the $pd\ensuremath{\rightarrow}^{3}\mathrm{He}\ensuremath{\eta}$ reaction at 1 GeV collected by the WASA detector at COSY.

Published
2014

26. Measurement of the analysing power in proton–proton elastic scattering at small angles

Author

S. Merzliakov, A. I. Kulikov, Ron L. Workman, D. Prasuhn, S. Dymov, D. Chiladze, Colin Wilkin, Yu. Valdau, H. Ströher, I. Keshelashvili, M. Hartmann, G.G. Macharashvili, Z. Bagdasarian, D. Mchedlishvili, V. Serdyuk, M. D. Tabidze, Hans Stockhorst, I. I. Strakovsky, A. Khoukaz, Rolf Stassen, B. Lorentz, Ralf Gebel, M. Papenbrock, A. Täschner, A.K. Kacharava, B. Gou, S.V. Trusov, M. S. Nioradze, V. Shmakova, S. Barsov, P. Kulessa, R. Maier, S. Mikirtychyants, H. Ohm, Frank Rathmann, Andreas Lehrach, D. Tsirkov, Yu. N. Uzikov, and N.L. Lomidze

Subjects
Nuclear and High Energy Physics, Analysing power, Proton, Silicon, chemistry.chemical_element, FOS: Physical sciences, Tracking (particle physics), law.invention, Telescope, Nuclear physics, law, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, Elastic scattering, Physics, Proton–proton elastic scattering, Detector, lcsh:QC1-999, Power (physics), chemistry, Physics::Accelerator Physics, Phase shift analysis, lcsh:Physics, Beam (structure)
Abstract

The proton analysing power in $\vec{p}p$ elastic scattering has been measured at small angles at COSY-ANKE at 796 MeV and five other beam energies between 1.6 and 2.4 GeV using a polarised proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. Although the analysing power results agree well with the many published data at 796 MeV, and also with the most recent partial wave solution at this energy, the ANKE data at the higher energies lie well above the predictions of this solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a much better description of these new measurements., Comment: 5 pages, 3 figures

Published
2014

27. Measuring the polarization of a rapidly precessing deuteron beam

Author

P. Lenisa, Z. Bagdasarian, A. Pesce, Ralf Gebel, B. Lorentz, P. Thörngren Engblom, J. Dietrich, Hans Stockhorst, Frank Rathmann, V. Hejny, R. Maier, S. Bertelli, E. J. Stephenson, L. Magallanes, V. Kamerdzhiev, Yu. Valdau, G. Fanourakis, H. Ströher, C. Weidemann, A. Nass, V. Shmakova, B. Gou, Richard Talman, D. Chiladze, Andreas Lehrach, D. Eversmann, G. Ciullo, M. Gaisser, D. Mchedlishvili, William Morse, S. Dymov, P. Wüstner, D. Oellers, G. Guidoboni, Yannis K. Semertzidis, D. Prasuhn, A.K. Kacharava, and J. Pretz

Subjects
Accelerator Physics (physics.acc-ph), Physics, 29.20.D- Cyclic accelerators and storage rings, 29.27.Hj Polarized beams, 29.27.Ac Beam injection and extraction, Nuclear and High Energy Physics, Polarization rotator, Physics and Astronomy (miscellaneous), Spin polarization, Linear polarization, business.industry, FOS: Physical sciences, Surfaces and Interfaces, Polarization (waves), Electric dipole moment, Optics, Precession, Radial polarization, lcsh:QC770-798, Physics - Accelerator Physics, ddc:530, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, business, Storage ring
Abstract

This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum J\"ulich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by re-sorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will produce sizeable magnitudes when the phase is left free to vary. An analysis procedure is described that matches the time dependence of the horizontal polarization to templates based on emittance-driven polarization loss while correcting for the positive bias. This information will be used to study ways to extend the horizontal polarization lifetime by correcting spin tune spread using ring sextupole fields and thereby to support the feasibility of searching for an intrinsic electric dipole moment using polarized beams in a storage ring. This paper is a combined effort of the Storage Ring EDM Collaboration and the JEDI Collaboration., Comment: 28 pages, 15 figures, prepared for Physical Review ST - Accelerators and Beams

Published
2014

28. Cross section ratio and angular distributions of the reaction p + d -> 3He + eta at 48.8 MeV and 59.8 MeV excess energy

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Nuclear Theory, Intermediate Energies, Eta, 01 natural sciences, 7. Clean energy, Nuclear physics, Cross section (physics), Tensor Analyzing Power, Deuterium, Near-Threshold, 0103 physical sciences, Energy interval, Physics::Accelerator Physics, ddc:530, 010306 general physics, Nuclear Experiment, Excess energy, Beam (structure)
Abstract

We present new data for angular distributions and on the cross section ratio of the p + d -> 3He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum J\"ulich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20 MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval., Comment: 9 pages, 9 figures

Published
2014

29. Toward polarized antiprotons: Machine development for spin-filtering experiments

Author

M. Mielke, V. Kamerdzhiev, P. Thörngren Engblom, S. Merzliakov, M. Papenbrock, S. Bertelli, H. Seyfarth, Alexander D. Vasiliev, M. Mikirtychiants, A. Nass, M. Statera, G. Tagliente, S. Mikirtychiants, G.G. Macharashvili, E. Steffens, S. Martin, A.K. Kacharava, Hans Stockhorst, M. Contalbrigo, B. Lorentz, M. D. Tabidze, Andreas Lehrach, Frank Rathmann, Ulf Bechstedt, G. Guidoboni, R. Engels, P. Wüstner, P. Lenisa, Yu. Valdau, D. Prasuhn, A. I. Kulikov, D. Mchedlishvili, Nikolai N. Nikolaev, Z. Bagdasarian, D. Schröer, D. Oellers, A. Pesce, K. Grigoriev, A. Khoukaz, H. J. Stein, Ralf Gebel, P. Goslawski, H. O. Meyer, C. Weidemann, H. Ströher, S.V. Trusov, M. Retzlaff, S. Barsov, R. Maier, S. Dymov, L. Barion, R. Schleichert, G. Ciullo, M. Gaisser, N.L. Lomidze, Helmut Soltner, and D. Chiladze

Subjects
electron, Accelerator Physics (physics.acc-ph), Nuclear and High Energy Physics, Physics and Astronomy (miscellaneous), Socio-culturale, FOS: Physical sciences, Kinetic energy, 01 natural sciences, Economica, 0103 physical sciences, Fysik, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Spin filtering, protons, 010308 nuclear & particles physics, scattering, storage ring, Surfaces and Interfaces, protons, scattering, performance, beam, electron, storage ring, hydrogen gas target, hydrogen gas target, Antiproton, Physical Sciences, lcsh:QC770-798, beam, Physics::Accelerator Physics, Development (differential geometry), Physics - Accelerator Physics, Atomic physics, performance
Abstract

Physical review / Special topics / Accelerators and beams 18(2), 020101 (2015). doi:10.1103/PhysRevSTAB.18.020101, Published by American Physical Society, {[S.l.]

Published
2014
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30. Electron and stochastic cooling at COSY

Author

H. J. Stein, Hans Stockhorst, D. Prasuhn, Rolf Stassen, R. Maier, and J. Dietrich

Subjects
Physics, Nuclear and High Energy Physics, Resolved sideband cooling, Proton, Electron, Synchrotron, law.invention, Nuclear physics, law, Laser cooling, Stochastic cooling, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Instrumentation, Storage ring, Electron cooling
Abstract

The synchrotron and storage ring COSY delivers proton beams with momenta between 300 and 3500 MeV/c for internal and external experiments. It is operating both with electron and stochastic cooling. The electron cooling is used mainly at the injection energy with 22 keV electrons to increase the intensity of the polarised proton beam with a combined cooling stacking injection. In addition, the electron-cooled proton beam is used for diagnostic purposes of machine parameters. The stochastic cooling for COSY is working in the proton momentum range between 1.5 and 3.5 GeV/c and is up to now only used for equilibrium experiments with thin internal targets and long #at top times. The longitudinal stochastic cooling system is extended by a fast frequency variable optical notch"lter to make use of a supercycle in COSY with from cycle to cycle varying #at top energies. The results of the electron cooling and stacking injection as well as the good results of the optical notch"lter for the stochastic cooling will be presented. ( 2000 Elsevier Science B.V. All rights reserved.

Published
2000

31. Suppressing intrinsic spin harmonics at the cooler synchrotron COSY

Author

Andreas Lehrach, D. Prasuhn, Ralf Gebel, R. Maier, and Hans Stockhorst

Subjects
Physics, Nuclear and High Energy Physics, Superlattice, Beam optics, Synchrotron, law.invention, law, Spin wave, Harmonics, Lattice (order), Physics::Accelerator Physics, Atomic physics, Instrumentation, Beam (structure), Electron cooling
Abstract

Accelerating a polarized beam in a synchrotron requires the highest possible superperiodicity of the lattice in order to minimize the number of depolarizing intrinsic resonances. However, at the cooler synchrotron COSY the standard lattice to accelerate the beam to maximum momentum has a reduced superperiodicity since the harmful transition energy is shifted upwards during acceleration. This procedure allows internal experiments to take data in the whole acceleration ramp. Unfortunately the reduced superperiodicity excites additional intrinsic resonances. To solve this contrary situation a modified beam optics was found which significantly lowers the strength of these intrinsic resonances. Measurements confirming this theoretical concept are presented.

Published
2000

32. Cooler synchrotron COSY

Author

H. Schneider, Hans Stockhorst, Ulf Bechstedt, A. Schnase, R. Tölle, D. Prasuhn, J. Dietrich, R. Maier, and S. Martin

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, Nuclear Theory, Synchrotron, law.invention, Momentum, Nuclear physics, Medium energy, law, Stochastic cooling, Physics::Accelerator Physics, Nuclear Experiment, Storage ring, Beam (structure)
Abstract

COSY Julich is a cooler synchrotron and storage ring delivering high precision beams with at present up to 5·10 10 protons with momenta between 600 MeV/c and 3.3 GeV/c for medium energy physics. Two cooling systems are used to accomplish this goal. An electron-cooling system that reaches up to a momentum of 645 MeV/c and a stochastic cooling system that covers the upper momentum range from 1500 to 3300 MeV/c. Since its inauguration in April 1993 substantial progress in developing beams for internal and external experiments has been achieved and the physics program is now running. At the beginning of 1996 a polarized proton beam could be successfully accelerated up to 820 MeV/c for the first time.

Published
1997

33. Measurement of thepn→ppπ0π−reaction in search for the recently observed resonance structure indπ0π0anddπ+π−systems

Author

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

Subjects
Nuclear physics, Mass enhancement, Physics, Nuclear and High Energy Physics, Roper resonance, Meson production, Pi, Analytical chemistry
Abstract

Exclusive measurements of the quasifree pn -> pp pi(0)pi(-) reaction have been performed by means of pd collisions at T-p = 1.2 GeV using the wide angle shower apparatus (WASA) detector setup at ...

Published
2013

34. Measurement of spin observables in the quasifreenp→{pp}sπ−reaction at 353 MeV

Author

P. Goslawski, M. Papenbrock, M. Mielke, M. Hartmann, B. Lorentz, Andreas Lehrach, S. Barsov, R. Engels, P. Wüstner, S. Dymov, Yu. N. Uzikov, D. Chiladze, S.V. Trusov, M. D. Tabidze, P. Benati, V. Shmakova, A. Dzyuba, H. Seyfarth, A.K. Kacharava, Hans Stockhorst, A. Khoukaz, H. J. Stein, D. Oellers, M. Mikirtychyants, P. Lenisa, V. Kurbatov, M. S. Nioradze, D. Tsirkov, G. Guidoboni, Colin Wilkin, Yu. Valdau, V. Lensky, T. Azaryan, P. Kulessa, H. Ströher, V. Serdyuk, S. Merzliakov, D. Prasuhn, D. Mchedlishvili, N.L. Lomidze, Vadim Baru, Ch. Weidemann, S. Mikirtytchiants, V. Kamerdzhiev, Q. J. Ye, H. Ohm, K. Grigoryev, Frank Rathmann, G.G. Macharashvili, A. I. Kulikov, E. Steffens, Ralf Gebel, M. Zhabitsky, V. Komarov, A. Polyanskiy, R. Maier, and M. Gaisser

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, 010308 nuclear & particles physics, Partial wave analysis, Observable, 01 natural sciences, 7. Clean energy, Deuterium, 0103 physical sciences, Pi, Atomic physics, 010306 general physics, Nucleon, Nuclear theory
Abstract

The transverse spin correlations ${A}_{x,x}$ and ${A}_{y,y}$ have been measured in the $\stackrel{P\vec}{d}\stackrel{P\vec}{p}\ensuremath{\rightarrow}{p}_{\text{spec}}{{pp}}_{s}{\ensuremath{\pi}}^{\ensuremath{-}}$ reaction at COSY-ANKE at 353 MeV per nucleon. Here ${{pp}}_{s}$ denotes a proton-proton pair with low excitation energy, which is dominantly in the ${}^{1}{S}_{0}$ state. By measuring three protons in the final state it was possible to extract events where there was a spectator proton ${p}_{\text{spec}}$ so that the reaction could be interpreted in terms of quasifree $\stackrel{P\vec}{n}\phantom{\rule{0.16em}{0ex}}\stackrel{P\vec}{p}\ensuremath{\rightarrow}{{pp}}_{s}{\ensuremath{\pi}}^{\ensuremath{-}}$. The proton and neutron analyzing powers in this reaction were also deduced from this data set by averaging over the polarizations of the deuteron beam and hydrogen target, respectively. The values of ${A}_{y}$ were shown to be consistent with a refined analysis of our earlier results obtained with a polarized proton incident on a deuterium target. Taking these data in combination with our previous measurements of the differential cross sections and analyzing powers in the $\stackrel{P\vec}{p}p\ensuremath{\rightarrow}{{pp}}_{s\phantom{\rule{0.16em}{0ex}}}{\ensuremath{\pi}}^{0}$ reaction, a more robust partial wave decomposition was achieved. Three different acceptable solutions were found, and the only way of resolving this ambiguity without further theoretical input would be through a measurement of the mixed spin-correlation parameter ${A}_{x,z}$.

Published
2013

35. Erratum: Synchrotron oscillation effects on an rf-solenoid spin resonance [Phys. Rev. ST Accel. Beams 15, 124202 (2012)]

Author

J. Dietrich, P. Lenisa, A. Polyanskiy, V. Kamerdzhiev, V. Hejny, B. Lorentz, Hans Stockhorst, Yu. Valdau, Frank Rathmann, C. Weidemann, E. J. Stephenson, P. Benati, M. Gaisser, A. Pesce, A.K. Kacharava, P. Kulessa, G. Guidoboni, Ralf Gebel, Yannis K. Semertzidis, D. Prasuhn, D. Chiladze, D. Mchedlishvili, P. Wüstner, William Morse, Andreas Lehrach, D. Öllers, H. Ströher, R. Maier, and Richard Talman

Subjects
Physics, Nuclear and High Energy Physics, Physics and Astronomy (miscellaneous), Condensed matter physics, Oscillation, Resonance, Solenoid, Surfaces and Interfaces, Synchrotron, law.invention, Nuclear physics, law, lcsh:QC770-798, ddc:530, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Spin (physics)
Published
2013

36. Search forη-mesic4He with the WASA-at-COSY detector

Author

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

Subjects
Excitation function, Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Detector, 01 natural sciences, Synchrotron, law.invention, Nuclear physics, law, 0103 physical sciences, Bound state, 010306 general physics
Abstract

An exclusive measurement of the excitation function for the dd -> (3)Hep pi(-) reaction was performed at the Cooler Synchrotron COSY-Julich with the WASA-at-COSY detection system. The data were ...

Published
2013

37. The cooler synchrotron COSY in Jülich

Author

Hans Stockhorst, D. Prasuhn, Ulf Bechstedt, A. Schnase, R. Maier, R. Tölle, S. Martin, H. Schneider, and J. Dietrich

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, Synchrotron, law.invention, Momentum, Nuclear physics, law, Stochastic cooling, Physics::Accelerator Physics, Nuclear Experiment, Instrumentation, Beam (structure), Storage ring, Electron cooling
Abstract

COSY Julich is a cooler synchrotron and storage ring with a proton momentum range from 270 to 3300 MeV/c. It has been conceived to deliver high precision beams for medium energy physics. To accomplish this goal two cooling systems are foreseen: an electron cooling system for the momentum range up to 645 MeV/c and a stochastic cooling system which covers the upper momentum range from 1500 to 3300 MeV/c. Proton beams in a wide momentum range have been delivered to internal as well as external experiments. The beam properties measured by these experiments and the main parameters of COSY are presented.

Published
1996

38. Synchrotron oscillation effects on an rf-solenoid spin resonance

Author

D. Öllers, D. Chiladze, P. Benati, Frank Rathmann, R. Maier, Yu. Valdau, H. Ströher, A. Polyanskiy, A. Pesce, Andreas Lehrach, P. Wüstner, Ralf Gebel, William Morse, J. Dietrich, V. Hejny, G. Guidoboni, Yannis K. Semertzidis, D. Prasuhn, Hans Stockhorst, A.K. Kacharava, M. Gaisser, C. Weidemann, V. Kamerdzhiev, P. Lenisa, Richard Talman, P. Kulessa, E. J. Stephenson, D. Mchedlishvili, and B. Lorentz

Subjects
solenoid, Nuclear and High Energy Physics, beam dynamics, Physics and Astronomy (miscellaneous), resonance [spin], elastic scattering, Art history, Juelich COSY PS, target [carbon], 01 natural sciences, NO, Nuclear physics, 0103 physical sciences, EDDA, ddc:530, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, 010306 general physics, time dependence [polarization], scintillation counter, Physics, 010308 nuclear & particles physics, measurement methods [electric moment], Beam polarization, Surfaces and Interfaces, sensitivity, effect [synchrotron oscillation], beam [deuteron], elastic scattering, analyzing power, sensitivity, analyzing power, beam profile, Physics::Accelerator Physics, lcsh:QC770-798, National laboratory, polarization [beam]
Abstract

New measurements are reported for the time dependence of the vertical polarization of a 0.97 GeV/c deuteron beam circulating in a storage ring and perturbed by an rf solenoid. The storage ring is the cooler synchrotron (COSY) located at the Forschungszentrum Jülich. The beam polarization was measured continuously using a 1.5 cm thick carbon target located at the edge of the circulating deuteron beam and the scintillators of the EDDA detector. An rf solenoid mounted on the ring was used to generate fields at and near the frequency of the 1-Gγ spin resonance. Measurements were made of the vertical beam polarization as a function of time with the operation of the rf solenoid in either fixed or continuously variable frequency mode. Using rf-solenoid strengths as large as 2.66×10^{-5} revolutions/turn, slow oscillations (∼1 Hz) were observed in the vertical beam polarization. When the circulating beam was continuously electron cooled, these oscillations completely reversed the polarization and showed no sign of diminishing in amplitude. But for the uncooled beam, the oscillation amplitude was damped to nearly zero within a few seconds. A simple spin-tracking model without the details of the COSY ring lattice was successful in reproducing these oscillations and demonstrating the sensitivity of the damping to the magnitude of the synchrotron motion of the beam particles. The model demonstrates that the characteristic features of measurements made in the presence of large synchrotron oscillations are distinct from the features of such measurements when made off resonance. These data were collected in preparation for a study of the spin coherence time, a beam property that needs to become long to enable a search for an electric dipole moment using a storage ring.

Published
2012

39. First internal and external experiments at COSY Juelich

Author

F. Mosel, C. Nake, J. Dietrich, D. Prasuhn, R. Tölle, S. Martin, Ulf Bechstedt, D. Grzonka, U. Hacker, R. Maier, and Hans Stockhorst

Subjects
Physics, Nuclear and High Energy Physics, Fabrication, Proton, Spectrometer, Synchrotron, law.invention, Nuclear physics, Acceleration, Deuterium, law, Atomic physics, Instrumentation, Liquid hydrogen, Beam (structure)
Abstract

The inauguration of the cooler synchrotron COSY Julich was celebrated on April 1st, 1993. After the first successful acceleration to proton momenta above 800 GeV/ c , beamtimes for experiments were scheduled in parallel to further machine development. The first experiment was the internal target experiment EDDA, which investigated the energy dependence of the p-p interaction. It makes use of a 3 × 4 μ m 2 thin CH 2 fiber as an internal target. The thickness of the fiber is more than adequate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10 7 p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/ c . Details of the target fabrication and the first experimental results will be discussed. Both external experimental facilities at COSY, the time-of-flight spectrometer, and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuterium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be presented. Two further internal experiments are prepared for the installation into the COSY ring. The target for the first experiment is a gas-jet target, the second experiment uses ribbon targets for the interaction. The status of both experimental setups will be shown.

Published
1995

40. Correcting systematic errors in high-sensitivity deuteron polarization measurements

Author

Andreas Lehrach, G. Venanzoni, Frederick Gray, M. da Silva e Silva, R. Messi, W.L. Kruithof, Yannis K. Semertzidis, D. Prasuhn, V. Dzordzhadze, D. Moricciani, P. Levi Sandri, C. J. G. Onderwater, Hans Stockhorst, Ralf Gebel, G. Noid, C. Ozben, A. Imig, D. M. Lazarus, Bernd Lorentz, William Morse, E. J. Stephenson, D.J. van der Hoek, Francesco Gonnella, N. P. M. Brantjes, Oscar Versolato, and Precision Frontier

Subjects
Nuclear and High Energy Physics, ANALYZING POWERS, 01 natural sciences, Particle detector, CARBON, Optics, 0103 physical sciences, Calibration, Deuteron, 010306 general physics, Instrumentation, Physics, Electric dipole moment, 010308 nuclear & particles physics, business.industry, Detector, Polarimeter, COSY, PERFORMANCE, Polarization (waves), ELASTIC-SCATTERING, POLARIMETER, business, Storage ring, INTERMEDIATE ENERGIES, Beam (structure)
Abstract

This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY at Julich. By measuring with very high statistical precision, the contributions that are second-order in the systematic errors become apparent. By calibrating the sensitivity of the polarimeter to such errors, it becomes possible to obtain information from the raw count rate values on the size of the errors and to use this information to correct the polarization measurements. During the experiment, it was possible to demonstrate that corrections were satisfactory at the level of 10(-5) for deliberately large errors. This may facilitate the real time observation of vector polarization changes smaller than 10(-6) in a search for an electric dipole moment using a storage ring. (C) 2011 Elsevier B.V. All rights reserved.

Published
2012

41. Abashian-Booth-Crowe resonance structure in the double pionic fusion to He-4

Author

R. Varma, I. Ozerianska, T. Tolba, A. Magiera, S. Schadmand, B. Mariański, P. Wuestner, K. Lalwani, B. Kamys, D. Pszczel, Hans Stockhorst, D. Lersch, Zbigniew Rudy, Rolf Stassen, Jozef Zlomanczuk, M. Berłowski, Patrik Adlarson, Benedykt R. Jany, B. Kłos, M. Buescher, C. Pauly, F. Hinterberger, T. Skorodko, F. S. Bergmann, Magnus Wolke, Eryk Czerwiński, G. Kemmerling, Frank Goldenbaum, P. Goslawski, Ankhi Roy, Stanisław Kistryn, R. Siudak, H. Ohm, W. Zipper, W. Bardan, Paweł Moskal, A. Trzciński, K. Foehl, H. Kleines, P. Vlasov, S. Sawant, Tomasz Bednarski, P. Podkopał, Lena Heijkenskjöld, J. Klaja, P. Zupranski, A. Pricking, N. Shah, D. Prasuhn, M. Bashkanov, H. Clement, Basanta Kumar Nandi, Alexander Schmidt, Wojciech Krzemien, G. Sterzenbach, B. Lorentz, E. Doroshkevich, X. Yuan, Pawel Plucinski, R. Maier, A. Jany, P. Kulessa, Marcin Zieliński, Bo Höistad, G. J. Wagner, C. Zheng, Y. Petukhov, K. Demmich, R. Engels, C. F. Redmer, A. Khoukaz, L. Yurev, W. Węglorz, K. T Brinkmann, W. Augustyniak, W. Eyrich, K. Grigoryev, J. Zabierowski, W. Erven, V. Sopov, Andrzej Kupsc, Antoni Szczurek, D. Coderre, M. Hodana, V. Hejny, Akira Yamamoto, L. Jarczyk, Carl-Oscar Gullström, M. Mikirtychiants, Magdalena Skurzok, Tord Johansson, Aleksandra Wrońska, E. Perez del Rio, Szymon Niedzwiecki, P. Wurm, Pawel Marciniewski, J. Ritman, V. Serdyuk, Jerzy Smyrski, Andzej Pyszniak, Hans Calén, Kjell Fransson, H. Stroeher, C. Husmann, L. Li, H. P. Morsch, H. Bhatt, K. Pysz, P. Fedorets, Ferdous Khan, F. Hauenstein, and J. Stepaniak

Subjects
Nuclear and High Energy Physics, Particle physics, Meson production, two-pion [mass spectrum], pair production [pi0], Juelich COSY PS, 0.4-0.7 GeV/nucleon, +helium+2pi0%22">deuteron deuteron --> helium 2pi0, 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Nuclear fusion, ddc:530, Collisions, Meson Production, WASA, Nuclear Experiment, 010306 general physics, Inclusive Reaction, Nuclear-Matter, Physics, Range (particle radiation), Fusion, fusion [deuteron deuteron], 010308 nuclear & particles physics, Dibaryons, energy dependence [channel cross section], Nuclear matter, width [resonance], angular dependence [differential cross section], Abc Enhancement, experimental results
Abstract

Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction dd -> He-4 pi(0)pi(0) have been performed in the energy range 0.8-1.4 GeV covering thus the region of the Abashian-Booth-Crowe effect, which denotes a pronounced low-mass enhancement in the pi pi invariant mass spectrum. The experiments were carried out with the WASA detector setup at the cooler synchrotron at Forshungszentrum Julich GmbH. Similar to the observation in the basic pn -> d pi(0)pi(0) reaction, the data reveal a correlation between the ABC effect and a resonancelike energy dependence in the total cross section. The maximum occurs at m = 2.37 GeV + 2m(N), i.e., at the same position as in the basic reaction. The observed resonance width Gamma approximate to 160 MeV can be understood from broadening due to Fermi motion of the nucleons in initial and final nuclei together with collision damping. Differential cross sections are described equally well by the hypothesis of a pn resonance formation during the reaction process.

Published
2012
Full Text
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42. New determination of the mass of the η meson at COSY-ANKE

Author

P. Goslawski, Andreas Lehrach, M. Hartmann, V. Serdyuk, T. Rausmann, S. Barsov, Hans Stockhorst, D. Prasuhn, H. Ströher, M. Mielke, Colin Wilkin, Ralf Gebel, S. Dymov, Yu. Valdau, D. Chiladze, R. Maier, B. Lorentz, T. Mersmann, P. Kulessa, A. Khoukaz, A. Täschner, I. Burmeister, S. Mikirtychiants, A.K. Kacharava, M. Papenbrock, and H. Ohm

Subjects
Nuclear and High Energy Physics, Particle physics, data analysis method, mass: measured [eta], Meson, resonance [spin], Nuclear Theory, FOS: Physical sciences, Juelich COSY PS, Nuclear physics, Momentum, +helium+eta%22">deuteron p --> helium eta, depolarization, nuclear reaction [p deuteron], threshold, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, Spin-½, Physics, ANKE, hadroproduction [eta], missing-mass [mass spectrum], Eta meson, Resonance, calibration, Deuterium, kinematics, polarized beam [deuteron], Production (computer science), High Energy Physics::Experiment, Relative precision, 1.57-1.59 GeV/c/nucleon, experimental results
Abstract

A value for the mass of the eta meson has been determined at the COSY-ANKE facility through the measurement of a set of deuteron laboratory beam momenta and associated 3He center-of-mass momenta in the d+p -> 3He+X reaction. The eta was then identified by the missing-mass peak and the production threshold determined. The individual beam momenta were fixed with a relative precision of 3 x 10^-5 for values around 3 GeV/c by using a polarized deuteron beam and inducing an artificial depolarizing spin resonance, which occurs at a well-defined frequency. The final-state momenta in the two-body d+p -> 3He+eta reaction were investigated in detail by studying the size of the 3He momentum ellipse with the forward detection system of the ANKE spectrometer. Final alignment of the spectrometer for this high precision experiment was achieved through a comprehensive study of the 3He final-state momenta as a function of the center-of-mass angles, taking advantage of the full geometrical acceptance. The value obtained for the mass, m(eta)=(547.873 +- 0.005(stat) +- 0.027(syst)) MeV/c^2, is consistent and competitive with other recent measurements, in which the meson was detected through its decay products., 11 pages, 11 figures, 3 tables, published version

Published
2012

43. Abashian-Booth-Crowe Effect in Basic Double-Pionic Fusion: A New Resonance?

Author

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

Subjects
Nuclear physics, Physics, Particle physics, Fusion, ddc:550, General Physics and Astronomy, Nuclear fusion, Fusion power, Nuclear Experiment, Resonance (particle physics)
Abstract

We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn -> d pi(0)pi(0) over the full energy region of the ABC effect, a pronounced low-mass enhancement in the pi pi-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t- channel Delta Delta process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m = 2.37 GeV, Gamma approximate to 70 MeV and I(J(P)) = 0(3(+)) in both pn and Delta Delta systems. Necessary further tests of the resonance interpretation are discussed.

Published
2011

44. Polarizing a stored proton beam by spin flip?

Author

Andreas Lehrach, G.G. Macharashvili, M. D. Tabidze, P. Goslawski, N. Dolfus, P. Zupranski, Giulio Stancari, M. Nekipelov, W. Erven, A. Smirnov, Hans Stockhorst, G. d'Orsaneo, A. Nass, B. Lorentz, S. Barsov, P. F. Dalpiaz, D. Oellers, S. Martin, M. Mielke, G. Ciullo, S.V. Trusov, A. Khoukaz, H. J. Stein, H. O. Meyer, P. Wüstner, M. Contalbrigo, Paolo Lenisa, M. Stancari, R. Engels, D. Prasuhn, M. Papenbrock, A. Garishvili, D. Spoelgen, D. Chiladze, H. Hadamek, P. Benati, S. Mikirtychiants, I.N. Meshkov, R. Maier, Frank Rathmann, H. Ströher, D. Welsch, P. Wieder, J. Sowinski, S. Dymov, A. Kulikov, G. Langenberg, H. Seyfarth, E. Steffens, H. Straatmann, J. Sarkadi, K. Grigoryev, M. Mikirtychiants, M. S. Nioradze, M. Statera, C. Weidemann, N.L. Lomidze, Ralf Gebel, J. Dietrich, Ulf Bechstedt, Nikolai N. Nikolaev, L. Barion, A. Vasilyev, S. Merzliakov, S. Bertelli, G. Tagliente, A.K. Kacharava, P. Thörngren Engblom, and R. Schleichert

Subjects
Nuclear and High Energy Physics, Polarized beams, Proton, 29.27.Hj, FOS: Physical sciences, 25.30.Bf, Electron, Antiprotons, Electron-proton scattering, Storage rings, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, 25.43.+t, Physics, Scattering, Electron–proton scattering, Antiproton, 29.20.D, Cathode ray, Physics::Accelerator Physics, Spin-flip, Atomic physics, Beam (structure), Storage ring
Abstract

We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin flip cross section in low-energy electron-proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam., 18 pages, 6 figures

Published
2009

45. Experimental Verification of Predicted Beam-Polarization Oscillations near a Spin Resonance

Author

D. W. Sivers, E. J. Stephenson, M. F. da Silva, A. Schnase, A. D. Krisch, Alex Chao, K. Ulbrich, Vasiliy Morozov, Bernd Lorentz, M. A. Leonova, Victor K. Wong, D. Welsch, C. J. G. Onderwater, R. Maier, Hans Stockhorst, Ralf Gebel, R. S. Raymond, Andreas Lehrach, D. Prasuhn, A. Garishvili, F. Hinterberger, N. P. M. Brantjes, and Research unit Nuclear & Hadron Physics

Subjects
Physics, Spin polarization, Scattering, SYNCHROTRON, General Physics and Astronomy, Solenoid, COSY, Polarization (waves), Charged particle, Synchrotron, law.invention, DEUTERONS, law, PROTONS, ddc:550, Physics::Accelerator Physics, SCATTERING, Atomic physics, Center frequency, Beam (structure)
Abstract

The Chao matrix formalism allows analytic calculations of a beam's polarization behavior inside a spin resonance. We recently tested its prediction of polarization oscillations occurring in a stored beam of polarized particles near a spin resonance. Using a 1.85 GeV/c polarized deuteron beam stored in the COoler SYnchrotron, we swept a new rf solenoid's frequency rather rapidly through 400 Hz during 100 ms, while varying the distance between the sweep's end frequency and the central frequency of an rf-induced spin resonance. Our measurements of the deuteron's polarization near and inside the resonance agree with the Chao formalism's predicted oscillations.

Published
2008

46. Determination of target thickness and luminosity from beam energy losses

Author

P. Wüstner, Yu. Valdau, H. Ströher, I. Keshelashvili, Hans Stockhorst, Rolf Stassen, T. Mersmann, Yoshikazu Maeda, A. Khoukaz, H. J. Stein, S. Mikirtychiants, M. Hartmann, Bernd Lorentz, S. Dymov, D. Prasuhn, Colin Wilkin, R. Maier, and A.K. Kacharava

Subjects
Physics, Accelerator Physics (physics.acc-ph), Nuclear and High Energy Physics, Luminosity (scattering theory), Physics and Astronomy (miscellaneous), Ion beam, Spectrometer, Scattering, Detector, FOS: Physical sciences, Surfaces and Interfaces, Nuclear physics, Cross section (physics), lcsh:QC770-798, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Physics - Accelerator Physics, Nuclear Experiment (nucl-ex), Nuclear Experiment, Storage ring, Beam (structure)
Abstract

The repeated passage of a coasting ion beam of a storage ring through a thin target induces a shift in the revolution frequency due to the energy loss in the target. Since the frequency shift is proportional to the beam-target overlap, its measurement offers the possibility of determining the target thickness and hence the corresponding luminosity in an experiment. This effect has been investigated with an internal proton beam of energy 2.65 GeV at the COSY-J\"ulich accelerator using the ANKE spectrometer and a hydrogen cluster-jet target. Possible sources of error, especially those arising from the influence of residual gas in the ring, were carefully studied, resulting in a accuracy of better than 5%. The luminosity determined in this way was used, in conjunction with measurements in the ANKE forward detector, to determine the cross section for elastic proton-proton scattering. The result is compared to published data as well as to the predictions of a phase shift solution. The practicability and the limitations of the energy-loss method are discussed., Comment: 11 pages, 11 figures

Published
2008
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47. Unexpected reduction of rf spin resonance strength for stored deuteron beams

Author

Bernd Lorentz, R. S. Raymond, F. Hinterberger, R. Maier, Victor K. Wong, K. Ulbrich, Hans Stockhorst, Ralf Gebel, Vasiliy Morozov, A. Schnase, M. A. Leonova, D. Prasuhn, Andreas Lehrach, D. W. Sivers, and A. D. Krisch

Subjects
Physics, Nuclear and High Energy Physics, Reduction (recursion theory), Physics and Astronomy (miscellaneous), Resonance, Surfaces and Interfaces, Electron, Resonance strength, Momentum, Dipole, Deuterium, lcsh:QC770-798, ddc:530, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Atomic physics, Spin-½
Abstract

Stored beams of polarized protons, electrons, or deuterons can be spin flipped by sweeping an rf dipole's or solenoid's frequency through an rf spin resonance. Fitting such data to the modified Froissart-Stora equation's spin resonance strength ${\mathcal{E}}_{\mathrm{FS}}$ gave very large deviations from the $^{*}\mathcal{E}_{Bdl}$ obtained from each rf magnet's $\ensuremath{\int}{B}_{rms}dl$. We recently varied an rf dipole's frequency sweep range $\ensuremath{\Delta}f$, and the momentum spread $\ensuremath{\Delta}p/p$ and betatron tune ${\ensuremath{\nu}}_{y}$ of stored $1.85\text{ }\text{ }\mathrm{GeV}/c$ polarized deuterons. We found a sharp constructive interference when ${\ensuremath{\nu}}_{y}$ was near an intrinsic spin resonance. Moreover, over large $\ensuremath{\Delta}f$ and $\ensuremath{\Delta}p/p$ ranges, ${\mathcal{E}}_{\mathrm{FS}}$ was about 7 times smaller than the predicted $^{*}\mathcal{E}_{Bdl}$.

Published
2007

48. Experimental test of the new analytic matrix formalism for spin dynamics

Author

R. S. Raymond, F. Hinterberger, A. Schnase, Victor K. Wong, Bernd Lorentz, R. Maier, K. Ulbrich, Vasiliy Morozov, Ralf Gebel, A. W. Chao, Andreas Lehrach, D. W. Sivers, D. Prasuhn, A. D. Krisch, Hans Stockhorst, and M. A. Leonova

Subjects
Physics, Nuclear and High Energy Physics, Physics and Astronomy (miscellaneous), Spin dynamics, Spin polarization, Beam polarization, Surfaces and Interfaces, Formalism (philosophy of mathematics), Dipole, Deuterium, Quantum electrodynamics, lcsh:QC770-798, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, ddc:530, Center frequency, Matrix formalism
Abstract

We recently started testing Chao's proposed new matrix formalism for describing the spin dynamics due to a single spin resonance. The Chao formalism is probably the first fundamental improvement of the Froissart-Stora equation in that it allows analytic calculations of the beam polarization's behavior inside a resonance. We tested the Chao formalism using a $1.85\text{ }\text{ }\mathrm{GeV}/c$ polarized deuteron beam stored in COSY, by sweeping an rf dipole's frequency through 200 Hz, while varying the distance from the sweep's end frequency to an rf-induced spin resonance's central frequency. Since the Froissart-Stora equation itself can make no prediction inside a resonance, we compared our experimental data with the predictions of the Chao formalism and those of an empirical two-fluid model based on the Froissart-Stora equation. The data strongly favor the Chao formalism.

Published
2007

49. Unexpected Enhancements and Reductions of RF Resonance Strengths

Author

B. Lorentz, Hans Stockhorst, F. Hinterberger, D. W. Sivers, M. A. Leonova, A. D. Krisch, Victor K. Wong, Vasiliy Morozov, R. Maier, A. Schnase, K. Ulbrich, Andreas Lehrach, D. Prasuhn, R. S. Raymond, and Ralf Gebel

Subjects
Physics, Dipole, Proton, Spin polarization, Spin echo, Electron, Spin-flip, Atomic physics, Betatron, Spin (physics)
Abstract

We recently analyzed all available data on spin-flipping stored beams of polarized protons, electrons, and deuterons. Fitting the modified Froissart-Stora equation to the measured polarization data after crossing an rf-induced spin resonance, we found 10 ‐20-fold deviations from the depolarizing resonance strength equations used for many years. The polarization was typically manipulated by linearly sweeping the frequency of an rf dipole or rf solenoid through an rf-induced spin resonance; spin-flip efficiencies of up to 99:9% were obtained. The Lorentz invariance of an rf dipole’s transverse R Bdl and the weak energy dependence of its spin resonance strength E together imply that even a small rf dipole should allow efficient spin flipping in 100 GeV or even TeV storage rings; thus, it is important to understand these large deviations. Therefore, we recently studied the resonance strength deviations experimentally by varying the size and vertical betatron tune of a 2:1 GeV=c polarized proton beam stored in COSY. We found no dependence of E on beam size, but we did find almost 100-fold enhancements when the rf spin resonance was near an intrinsic spin resonance.

Published
2007

50. Antiproton chain of the FAIR storage rings

Author

F. Herfurth, Yu. A. Litvinov, Andreas Lehrach, D. Prasuhn, M. Steck, V. Kamerdzhiev, Michael Lestinsky, R. Maier, Thomas Stöhlker, Takeshi Katayama, Hans Stockhorst, and Rolf Stassen

Subjects
Physics, High energy, Particle physics, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, law.invention, Nuclear physics, Antiproton beam, Beam physics, Antiproton, law, Stochastic cooling, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Nuclear Experiment, Mathematical Physics, Storage ring, Beam (structure), Electron cooling
Abstract

In the Modularized Start Version of the Facility of Antiproton and Ion Research (FAIR) at Darmstadt Germany, the 3 GeV antiprotons are precooled in the collector ring and accumulated in the high energy storage ring (HESR). They are further accelerated to 14 GeV or decelerated to 1 GeV for the experiments with a high-density internal target. The powerful beam cooling devices, stochastic cooling and electron cooling will support the provision of a high-resolution antiproton beam. The other option of FAIR is to prepare the low energy, 300 keV antiproton beam connecting the existing storage rings ESR and CRYRING with HESR. Beam physics issues related with these concepts are described.

Published
2015

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