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1. 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

2. 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

3. Search for light vector boson production ine+e−→μ+μ−γinteractions with the KLOE experiment

Author

R. Messi, T. Johansson, S. Giovannella, Aleksander Gajos, Antonio Budano, S. Miscetti, K. Kacprzak, F. Bossi, R. Di Salvo, E. Dané, G. Felici, Vincenzo Patera, Andrzej Kupsc, S. Loffredo, Wojciech Wiślicki, Paweł Moskal, M. Martemianov, F. Happacher, Jarosław Zdebik, G. Giardina, Daria Kamińska, D. Domenici, P. De Simone, Gianfranco Morello, A. Passeri, A. Di Cicco, Marco Schioppa, Magnus Wolke, P. Gauzzi, F. Loddo, G. Venanzoni, A. De Santis, M. Mascolo, C. Bloise, Michał Silarski, A. Ranieri, F. Nguyen, Barbara Sciascia, M. Martini, A. Di Domenico, G. De Robertis, P. Santangelo, A. Palladino, Eryk Czerwiński, L. Caldeira Balkeståhl, I. Sarra, O. Erriquez, S. Fiore, Bo Höistad, G. Fanizzi, E. Graziani, G. Bencivenni, D. Babusci, V. De Leo, D. Moricciani, F. Ceradini, E. De Lucia, I. Balwierz-Pytko, Giuseppe Mandaglio, I. Prado Longhi, P. Franzini, J. Lee-Franzini, Lena Heijkenskjöld, Wojciech Krzemien, P. Branchini, P. Ciambrone, Francesca Curciarello, L. Tortora, and A. Fantini

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Antiparticle, Electron–positron annihilation, Antimatter, High Energy Physics::Experiment, Elementary particle, Vector boson, Boson, Lepton
Abstract

We have searched for a light vector boson U, the possible carrier of a "dark force", with the KLOE detector at the DA Phi NE e(+)e(-) collider, motivated by astrophysical evidence for the presence of dark matter in the Universe. Using e(+)e(-) collisions collected with an integrated luminosity of 239.3 pb(-1), we look for a dimuon mass peak in the reaction e(+)e(-) -> mu(+)mu(-)gamma, corresponding to the decay U -> mu(+)mu(-). We find no evidence for a U vector boson signal. We set a 90% CL upper limit for the mixing parameter squared between the photon and the U boson of 1.6 x 10(-5) to 8.6 x 10(-7) for the mass region 520 < m(U) < 980 MeV.

Published
2014

4. 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

5. A new limit on the CP violating decay KS→3π0 with the KLOE experiment

Author

Paweł Moskal, M. Martemianov, C. F. Redmer, P. Franzini, J. Lee-Franzini, G. Fanizzi, G. Venanzoni, D. Moricciani, G. Capon, V. De Leo, E. De Lucia, I. Balwierz-Pytko, F. Nguyen, I. Prado Longhi, Cecilia Taccini, Magnus Wolke, B. Leverington, Lena Heijkenskjöld, C. Di Donato, K. Kacprzak, P. Gauzzi, F. Loddo, Giuseppe Mandaglio, S. Loffredo, L. Tortora, L. Iafolla, S. Fiore, A. De Santis, P. Ciambrone, Michał Silarski, Bo Höistad, O. Erriquez, Marek Jacewicz, A. Ranieri, P. Santangelo, Francesca Curciarello, Antonio Budano, G. Giardina, E. Graziani, A. Passeri, Vincenzo Patera, Andrzej Kupsc, Marco Schioppa, A. Di Domenico, Cesare Bini, A. Fantini, Jarosław Zdebik, Barbara Sciascia, M. Martini, S. Giovannella, Eryk Czerwiński, G. Bencivenni, S. Miscetti, D. Domenici, W. Wiślicki, F. Gonnella, D. Babusci, Gianfranco Morello, L. Caldeira Balkeståhl, I. Sarra, F. Bossi, E. Dané, R. Messi, T. Johansson, C. Bloise, M. Mascolo, R. Di Salvo, F. Happacher, P. Branchini, G. De Robertis, G. Felici, Davide Badoni, and F. Ceradini

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, 010308 nuclear & particles physics, 01 natural sciences, Standard Model, Calorimeter, Nuclear physics, 0103 physical sciences, CP violation, Direct search, Limit (mathematics), 010306 general physics
Abstract

We have carried out a new direct search for the CP violating decay K-S -> 3 pi(0) with 1.7 fb(-1) of e(+)e(-) collisions collected by the KLOE detector at the Phi-factory DA Phi NE. We have searched for this decay in a sample of about 5.9 x 10(8) KSKL events tagging the K-S by means of the K-L interaction in the calorimeter and requiring six prompt photons. With respect to our previous search, the analysis has been improved by increasing of a factor four the tagged sample and by a more effective background rejection of fake K-S tags and spurious clusters. We find no candidates in data and simulated background samples, while we expect 0.12 standard model events. Normalizing to the number of K-S -> 2 pi(0) events in the same sample, we set the upper limit on BR(K-S -> 3 pi(0))

Published
2013

6. Precision measurement of σ(e+e−→π+π−γ)/σ(e+e−→μ+μ−γ) and determination of the π+π− contribution to the muon anomaly with the KLOE detector

Author

A. Di Domenico, P. Lukin, S. Mueller, P. Gauzzi, A. De Santis, Marco Schioppa, F. Loddo, O. Erriquez, M. Wolke, W. Kluge, P. Ciambrone, E. Dané, F. Nguyen, D. Babusci, Francesca Curciarello, Barbara Sciascia, W. Wislicki, M. Martini, D. Domenici, G. Felici, F. Ceradini, A. Passeri, Vincenzo Patera, Li Caldeira Balkeståhl, Eryk Czerwiński, Andrzej Kupsc, D. Moricciani, Giuseppe Mandaglio, G. Fanizzi, P. Branchini, J. Zdebik, S. Miscetti, S. Giovannella, J. Lee-Franzini, I. Prado Longhi, R. Versaci, P. De Simone, G. Bencivenni, M. Mascolo, I. Sarra, Cecilia Taccini, V. De Leo, G. Giardina, E. De Lucia, F. Bossi, I. Balwierz-Pytko, Davide Badoni, G. De Robertis, P. Franzini, L. Iafolla, G. Venanzoni, S. Fiore, Tord Johansson, Bo Höistad, L. Tortora, Lena Heijkenskjöld, E. Graziani, Marek Jacewicz, Antonio Budano, A. Ranieri, C. F. Redmer, E. Iarocci, Cesare Bini, F. Happacher, Gianfranco Morello, F. Gonnella, C. Bloise, G. Capon, P. Santangelo, R. Messi, C. Di Donato, Paweł Moskal, M. Martemianov, and Michał Silarski

Subjects
Physics, Nuclear and High Energy Physics, Muon, Meson, 010308 nuclear & particles physics, Electron–positron annihilation, Hadron, Form factor (quantum field theory), 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, 010306 general physics, Lepton, Dimensionless quantity
Abstract

We have measured the ratio cr (e(+)e(-) -> pi(+)pi(-)gamma)/sigma(e(+)e(-) -> mu(+)mu(-)gamma), with the KLOE detector at DA Phi NE for a total integrated luminosity of similar to 240 pb(-1). From this ratio we obtain the cross section sigma (e(+)e(-) -> pi(+)pi(-)gamma). From the cross section we determine the pion form factor vertical bar F-pi vertical bar(2) and the two-pion contribution to the muon anomaly a(mu) for 0.592< M-pi pi < 0.975 GeV, Delta(pi pi) a(mu) = (385.1 +/- 1.1(stat) +/- 2.7(sys+theo)) x 10(-10). This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly. (c) 2013 Elsevier B.V. All rights reserved.

Published
2013

7. Search for a vector gauge boson in ϕ meson decays with the KLOE detector

Author

Anna Bozena Kowalewska, A. Ranieri, E. Iarocci, A. Di Domenico, Cesare Bini, Barbara Sciascia, M. Martini, C. Bloise, P. Ciambrone, Cecilia Taccini, I. Prado Longhi, Vincenzo Patera, Andrzej Kupsc, P. Franzini, Giuseppe Mandaglio, G. Venanzoni, L. Iafolla, S. Fiore, Bo Höistad, G. De Robertis, Marco Schioppa, A. Sciubba, F. Bossi, E. Graziani, D. Domenici, C. F. Redmer, Davide Badoni, G. Bencivenni, S. A. Bulychjev, L. Tortora, R. Messi, M. Matsyuk, S. Giovannella, G. Felici, Jarosław Zdebik, D. Babusci, F. Ceradini, G. De Zorzi, V. Bocci, Eryk Czerwiński, Marek Jacewicz, I. Sarra, J. Lee-Franzini, I. Balwierz, G. Capon, O. Erriquez, Antonio Budano, A. Passeri, R. Versaci, Michał Silarski, F. Archilli, F. Happacher, Stefania Antonia Stucci, E. De Lucia, Tord Johansson, G. Giardina, D. Moricciani, S. Miscetti, Li Caldeira Balkeståhl, F. Nguyen, Magnus Wolke, P. Gauzzi, V. Kulikov, F. Loddo, Gianfranco Morello, F. Gonnella, E. Dané, P. Branchini, C. Di Donato, M. Mascolo, Paweł Moskal, M. Martemianov, P. Santangelo, Pierluigi Campana, W. Wislicki, A. De Santis, G. Fanizzi, Archilli, F, Ceradini, Filippo, and PRADO LONGHI, Ivan

Subjects
Dark forces, Nuclear and High Energy Physics, Particle physics, Meson, Electron–positron annihilation, e+e− collisions, Hadron, Elementary particle, $e ^{+} e^{−}$ collisions, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, 0103 physical sciences, gauge vector boson, 010306 general physics, Boson, Physics, Gauge boson, 010308 nuclear & particles physics, Phi meson, 3. Good health, dark forces, Physics::Accelerator Physics, e+e- collisions, High Energy Physics::Experiment, Gauge vector boson, Lepton
Abstract

The existence of a light dark force mediator has been tested with the KLOE detector at DAPHNE. This particle, called U, is searched for using the decay chain phi-->etaU, eta-->pi+pi-pi0, U-->e+e-. No evidence is found in 1.5 fb-1 of data. The resulting exclusion plot covers the mass range 5, Comment: 13 pages, 8 figures

Published
2012

8. 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

9. 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

10. Observation of the rare η→e+e−e+e− decay with the KLOE experiment

Author

E. De Lucia, R. Messi, Marco Schioppa, A. Di Domenico, Flavio Archilli, A. Ranieri, V. Bocci, Paweł Moskal, M. Martemianov, P. Massarotti, Vincenzo Patera, Andrzej Kupsc, C. Bloise, Stefan E. Müller, E. Iarocci, Barbara Sciascia, M. Martini, F. Ceradini, B. Di Micco, A. Sciubba, M. Napolitano, L. Tortora, Michał Silarski, P. De Simone, S. Meola, J. Lee-Franzini, P. Santangelo, G. Felici, O. Erriquez, D. Domenici, M. A. Matsyuk, Marek Jacewicz, I. Balwierz, Claudio Gatti, F. Bossi, I. Prado Longhi, Magnus Wolke, P. Gauzzi, F. Loddo, Gianfranco Morello, M. Moulson, A. De Santis, S. Miscetti, Simona Serena Bocchetta, S. A. Bulychjev, S. Giovannella, C. Di Donato, G. De Robertis, Antonio Budano, T. Spadaro, W. Wiślicki, D. Babusci, G. Venanzoni, G. Xu, R. Versaci, A. Denig, Pierluigi Campana, Davide Badoni, A. Passeri, P. Ciambrone, G. Bencivenni, G. De Zorzi, F. Ambrosino, T. Capussela, Massimo Antonelli, Eryk Czerwiński, I. Sarra, Cecilia Taccini, F. Happacher, Tord Johansson, A. Antonelli, S. Fiore, Bo Höistad, E. Graziani, P. Franzini, Cesare Bini, D. Moricciani, Jarosław Zdebik, E. Dané, G. Capon, M. Palutan, F. Gonnella, F. Nguyen, P. Branchini, M. Dreucci, G. Fanizzi, and V. V. Kulikov

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Branching fraction, Electron–positron annihilation, 0103 physical sciences, Radiation, 010306 general physics, 01 natural sciences
Abstract

We report the first observation of the rare η → e + e − e + e − ( γ ) decay based on 1.7 fb − 1 collected by the KLOE experiment at the DAΦNE ϕ-factory. The selection of the e + e − e + e − final state is fully inclusive of radiation. We have identified 362 ± 29 events resulting in a branching ratio of ( 2.4 ± 0.2 stat + bckg ± 0.1 syst ) × 10 − 5 .

Published
2011

11. ΔΔ excitation in proton–proton induced π0π0 production

Author

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

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

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

Published
2011

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

Author

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

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

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

Published
2010

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

Author

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

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

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

Published
2010

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

Author

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

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

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

Published
2009

15. MEASUREMENT OF THE ω MESON POLARIZATION IN THE pd → 3<font>He</font> ω REACTION AT 1360 AND 1450 MeV

Author

Andrzej Kupsc, Karin Schönning, C. Wilkin, T. Johansson, Jozef Zlomanczuk, Bo Höistad, Hans Calén, and Kjell Fransson

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Near threshold, Low energy, Meson, Hadron, General Physics and Astronomy, Polarization (waves), Coincidence
Abstract

The tensor polarization of ω mesons produced in the pd → 3 He ω reaction has been measured at two energies near threshold. The 3 He nuclei were detected in coincidence with the π0π+π- or π0γ decay products of the ω. The ω mesons are found to be unpolarised, which is in complete contrast to the case of ϕ-meson production from the corresponding reaction pd → 3 He ϕ. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.

Published
2009

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

Author

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

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

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

Published
2009

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

Author

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

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

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

Published
2008

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

Author

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

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

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

Published
2007

19. OBSERVATION OF THE ABC EFFECT IN THE FIRST EXCLUSIVE MEASUREMENTS OF pn → dπ0π0

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Complete data, Quantum mechanics, Spectrum (functional analysis), Bound state, Theoretical models, Prove it, Astronomy and Astrophysics, Invariant mass, Atomic physics, Atomic and Molecular Physics, and Optics, Excitation
Abstract

The reaction pn → dπ0π0 constitutes the most fundamental system for the study of the ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of the ππ system in double-pionic fusion to nuclear bound states. The first exclusive measurements of this reaction have now been carried out at CELSIUS-WASA. They exhibit a striking low-mass enhancement in the ππ invariant mass spectrum, prove it to be a σ-channel phenomenon and falsify conventional theoretical models, which predict an associated high-mass enhancement not present in the new exclusive data. In the kinematically complete data sample we observe a ΔΔ excitation, where the interaction between the two Δ obviously plays a crucial role for the generation of the ππ low-mass enhancement.

Published
2007

20. ππ PRODUCTION IN PROTON-PROTON COLLISIONS

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Fusion, Complete data, Range (particle radiation), Proton, Excited state, Astronomy and Astrophysics, Invariant mass, Production (computer science), Atomic physics, Atomic and Molecular Physics, and Optics, Excitation
Abstract

At CELSIUS-WASA the two-pion production in proton-proton collisisons has been measured exclusively from threshold up to the energy regime, where both of the collision partners are expected to be excited to the Δ state. The measurements constitute the first kinematically complete data samples of solid statistics in this energy range. Most of the data have been obtained for the π+π- and π0π0channels. Whereas at near-threshold energies the differential distributions can be succesfully explained by chiral dynamics and Roper excitation, respectively, the data for the π+π- channel in the ΔΔ region can be described only, if the special configuration (ΔΔ)0+ is assumed. The data for the π0π0 channel moreover exhibit a low-mass enhancement in the π0π0 invariant mass spectrum, which is reminiscent of the ABC-effect found in double-pionic fusion to light nuclei.

Published
2007

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

Author

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

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

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

Published
2007

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

Author

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

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

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

Published
2007

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

Author

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

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

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

Published
2006

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

Author

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

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

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

Published
2005

26. Study of baryon and search for dibaryon resonances by the $pp \rightarrow pp\pi^ + \pi^-$ reaction

Author

S. Häggström, T. Johansson, B. Morosov, J. Stepaniak, M. Bashkanov, Hans Calén, Kjell Fransson, W. Brodowski, J. Pätzold, Wolfgang Scobel, Jozef Zlomanczuk, J. Zabierowski, H. Clement, Andrzej Kupsc, Z. Wilhelmi, G. J. Wagner, A. Sukhanov, Arne Johansson, J. Greiff, J. Johanson, K. Kilian, C. Ekström, W. Oelert, Bo Höistad, Roger Ruber, S. Kullander, R. Meier, A. Turowiecki, R. Bilger, E. Doroshkevich, and Pawel Marciniewski

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Branching fraction, Nuclear Theory, Hadron, Baryon, Nuclear physics, Deuterium, Pi, Nuclear fusion, Production (computer science), Nuclear Experiment, Charge exchange
Abstract

Exclusive measurements of the two-pion production channel $pp \rightarrow pp\pi^ + \pi^-$ have been carried out near threshold at CELSIUS with the PROMICE/WASA detector. They reveal $pp \rightarrow pp^*(1440)\rightarrow pp\sigma \rightarrow pp(\pi^ + \pi^-)_{I = \ell = 0}$ as the dominant process at these energies, however, the data exhibit also significant contributions from $p^*(1440) \rightarrow \Delta \pi \rightarrow p(\pi^ + \pi^-)_{I = \ell = 0}$ . From the observed interference of these Roper decay routes their relative branching ratio is derived. The status on the search for NN-decoupled $NN\pi$ -resonances is reviewed with regard to recent experimental searches in the pionic double charge exchange in nuclei, the two-pion production in nucleon-nucleon collisions, the photo pion-production on the deuteron and the electro pion-production in nuclei.

Published
2003

27. First results from the CELSIUS/WASA facility

Author

Z. Wilhelmi, V. Tchernyshev, V. Tikhomirov, P.-E. Tegnér, L. Gustafsson, N. Kimura, R. Shafigulin, D. Reistad, M. Bashkanov, K. Lindberg, J. Zabierowski, D. Bogoslawsky, J. Greiff, A. Nawrot, C. Bargholz, Arne Johansson, P. Marciniewski, T. Skorodko, S. Keletea, H. Yamaoka, Hans Calén, H. Clement, L. Demiroers, Y. Petukhov, Bo Höistad, A. Kipsc, F. Cappellaro, S. Kullander, B.A. Shwartz, Kjell Fransson, W. Oelert, Tord Johansson, S. Sandukovsky, B. M. K. Nefkens, V. Sopov, J. Zlomanczuk, A. Povtorejko, E. Jiganov, Ulrich Wiedner, W. Scobel, Marek Jacewicz, E. Dorochkevitch, Curt Ekstrom, I. Koch, Roger Ruber, B. Morosov, P. Thörngren Engblom, J. Stepaniak, G.J. Wagner, M. Gornov, Akira Yamamoto, A. Turowiecki, G. Ivanov, C. Pauly, A. A. Kuznetsov, and C.-J. Fridén

Subjects
Physics, Nuclear and High Energy Physics, Degree Celsius, Nuclear engineering
Published
2003

28. Two-pion production in proton–proton collisions near threshold

Author

W. Oelert, J. Greiff, W. Brodowski, P. Marciniewski, B. Morosov, H. Clement, R. Bilger, S. Kullander, T. Sefzick, J. Johanson, Hans Calén, J. Stepaniak, A. Sukhanov, I. Koch, A. Khoukaz, Roger Ruber, Curt Ekstrom, Kjell Fransson, Arne Johansson, L. Gustafsson, S. Häggström, Bo Höistad, Tord Johansson, J. Zabierowski, J. Zlomanczuk, Andrzej Kupsc, W. Scobel, G.J. Wagner, B.A. Shwartz, and A. Povtorejko

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Proton, Nuclear Theory, Detector, Nuclear physics, Near threshold, Pion, Cluster (physics), High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Storage ring
Abstract

Two-pion production reactions in proton-proton collisions have been studied using the PROMICE/WASA detector and an internal cluster gas-jet target at the CELSIUS storage ring in Uppsala. Three out ...

Published
2002

29. THE pp → ppπ0π0 REACTION AND ITS LIMITING CASE, FUSION TO QUASI-BOUND 2<font>He</font>, IN SEARCH OF THE ABC EFFECT

Author

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

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Fusion, Pi, Astronomy and Astrophysics, Limiting case (mathematics), Atomic and Molecular Physics, and Optics, Excitation
Abstract

The π0π0 production in pp -collisions has been investigated in exclusive and kinematically complete measurements from threshold up to Tp = 1.4 GeV . For incident energies Tp > 1 GeV , i.e. in the region beyond the Roper excitation, the ΔΔ excitation process takes over. The data are well explained by the t-channel ΔΔ process dominated by pion exchange. There is no low-mass enhancement (ABC effect) in the π0π0-invariant mass distribution beyond that given by the conventional t-channel ΔΔ process. This is also true for the limiting case, where the protons are in the quasi-bound 2 He state.

Published
2011

30. 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

31. 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

32. Evidence for a New Resonance from Polarized Neutron-Proton Scattering

Author

A. Magiera, M. Buescher, James Ritman, M. Mikirtychiants, Magdalena Skurzok, F. Hauenstein, T. Sefzick, A. Taeschner, H. Stockhorst, L. Yurev, K. Lalwani, J. Stepaniak, Jozef Zlomanczuk, Frank Goldenbaum, G. J. Wagner, A. Khoukaz, Paweł Moskal, Tord Johansson, Wojciech Krzemien, M. Krapp, P. Goslawski, R. Stassen, B. Kamys, P. Zupranski, F. S. Bergmann, A. Zink, M. Hodana, W. Eyrich, K. Foehl, A. Pricking, D. Lersch, K. Pysz, P. Fedorets, Ferdous Khan, H. Stroeher, I. I. Strakovsky, Aleksandra Wrońska, E. Perez del Rio, H. Ohm, N. Huesken, Günter Kemmerling, Izabela Ciepał, A. Goswami, M. Bashkanov, P. Wurm, Di. Kirillov, R. Varma, H. P. Morsch, C. F. Redmer, K. Grigoryev, A. Erven, E. Doroshkevich, M. Wolke, Hans Calén, I. Ozerianska, J. Zabierowski, A. Pyszniak, W. Augustyniak, Bo Höistad, A. Jany, Antoni Szczurek, W. J. Briscoe, D. Pszczel, Kjell Fransson, P. Podkopał, Andrzej Kupsc, Akira Yamamoto, A. Trzciński, Said Data Anal Ctr, M. Berłowski, S. Schadmand, R. Maier, L. Jarczyk, Stanisław Kistryn, B. Lorentz, P. Wuestner, V. Hejny, Anubhab Roy, Lena Heijkenskjöld, T. Skorodko, E. Stephan, V. Sopov, P. Adlarson, K. Demmich, Zbigniew Rudy, Pawel Marciniewski, R. Siudak, Eryk Czerwiński, Harald Kleines, V. Serdyuk, Jerzy Smyrski, B. Kłos, G. Sterzenbach, Ralf Engels, Ron L. Workman, S. Sawant, W. Erven, Marcin Zieliński, B. Mariański, P. Kulessa, H. Clement, C.-O. Gullström, N.M. Piskunov, H. Bhatt, Benedykt R. Jany, Maria Zurek, W. Bardan, D. Prasuhn, and D. Coderre

Subjects
Physics, Elastic scattering, States, Scattering, Partial wave analysis, Dibaryon, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Hexaquark, Analyzing Power, Resonance (particle physics), Nuclear physics, Angular distribution, Elastic-Scattering, Proton scattering, ddc:550, Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, Partial-Wave Analysis, Spin Observables
Abstract

Exclusive and kinematically complete high-statistics measurements of quasifree polarized (n) over right arrowp scattering have been performed in the energy region of the narrow resonancelike structure d* with I(J(P)) = 0(3(+)),M approximate to 2380 MeV, and Gamma approximate to 70 MeV observed recently in the double-pionic fusion channels pn -> d pi(0)pi(0) and pn -> d pi(+)pi(-). The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process (d) over right arrowp -> np + p(spectator). This allowed the np analyzing power, A(y), to be measured over a broad angular range. The obtained A(y) angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new A(y) data into the SAID analysis produces a pole in the D-3(3) - (3)G(3) waves in support of the d* resonance hypothesis.

Published
2014

33. Spectator tagging in quasi-free proton–neutron interactions in deuterium using an internal cluster-jet target at a storage ring

Author

W. Brodowski, K. Kilian, P. Sundberg, G. J. Wagner, Andrzej Kupsc, V. B. Dunin, T. Johansson, B. Morosov, J. Dyring, A. Sukhanov, A. Turowiecki, C. Ekström, T. Neubauer, B. Shwartz, J. Stepaniak, Hans Calén, J Greiff, Pawel Marciniewski, Kjell Fransson, Jozef Zlomanczuk, Z. Wilhelmi, J. Zabierowski, Roger Ruber, I. Koch, S. Kullander, Leif Gustafsson, J. Johanson, W. Oelert, R. Bilger, H. Clement, Arne Johansson, Colin Wilkin, and Bo Höistad

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Proton, Scattering, Nuclear Theory, Resolution (electron density), The Svedberg Laboratory, Nuclear physics, Deuterium, Neutron, Atomic physics, Nuclear Experiment, Instrumentation, Storage ring
Abstract

Low-energy spectator protons (p s ) from quasi-free proton–neutron interactions on deuterium have been measured for the pd→dπ 0 p s and pd→pnπ 0 p s reactions at the CELSIUS storage ring of the The Svedberg Laboratory. The experiment used 320 MeV protons incident on a deuterium cluster-jet target. The spectator protons were detected inside the scattering chamber using a silicon detector system which is compatible with a high vacuum. The low target density allows the spectator proton emerge without undergoing significant secondary scattering. Its measurement is therefore a useful tag upon such reactions, allowing cross-sections for quasi-free reactions to be deduced at well-defined centre-of-mass energies. The comparison with the simulation for the pd→dπ 0 p s reaction shows that the energy dependence of the pn→dπ 0 cross-section can be extracted near the threshold. The method greatly improves the experimental resolution achievable in quasi-free p–n reaction studies.

Published
2001

34. Differential cross sections of the pp → ppπ0 reaction from 310 to 425 MeV

Author

G. J. Wagner, Z. Wilhelmi, J. Zabierowski, H. Clement, J. Johanson, C. Ekström, W. Brodowski, Jozef Zlomanczuk, J. Dyring, A. Sukhanov, U. Schuberth, Andrzej Kupsc, B. Morosov, Pawel Marciniewski, A. Turowiecki, Hans Calén, Kjell Fransson, Leif Gustafsson, B. Shwartz, J. Stepaniak, S. Kullander, S. Häggström, A. Mörtsell, R. Bilger, T. Johansson, W. Oelert, Roger Ruber, K. Kilian, P. Sundberg, Bo Höistad, A. Zernov, Arne Johansson, Colin Wilkin, and Göran Fäldt

Subjects
Nuclear reaction, Physics, Nuclear physics, Nuclear and High Energy Physics, Degree Celsius, Storage ring, Differential (mathematics)
Abstract

Measurements of the differential cross sections of the pp --> pp pi(0) reaction at 310, 320, 340, 360, 400 and 425 MeV have been carried out at the CELSIUS storage ring in Uppsala. An attempt ha ...

Published
2000

35. Excitation of the Roper resonance in single- and double-pion production in nucleon-nucleon collisions⋆

Author

B. Morosov, Henrik Petterson, K. Franssen, E. Jiganov, M. Wolke, Hans Calén, O. Khakimova, F. Cappellaro, T. Skorodko, Karin Schönning, L. Gustafsson, H. Clement, P. Thörngren-Engblom, I. Koch, L. Demiroers, B.A. Shwartz, J. Stepeniak, R. Meier, D. Duniec, Sven Kullander, G. Ivanov, P. Marciniewski, G.J. Wagner, Akira Yamamoto, A. Povtorejko, Marek Jacewicz, M. Bashkanov, A. A. Kuznetsov, Curt Ekstrom, Y. Petukhov, M. Kaskulov, V. Sopov, J. Zlomanczuk, F. Kren, Bo Höistad, Wolfgang Scobel, C. Pauly, V. Tikhomirov, E. Doroshkevich, J. Zabierowski, S. Keleta, A. Kupść, D. Bogoslawsky, and Tord Johansson

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Roper resonance, Pair production, Pion, Meson, Branching fraction, Nuclear Theory, Nuclear Experiment, Nucleon, Excitation
Abstract

In most investigations the Roper resonance is sensed only very indirectly via complex partial-wave analyses. We find indications for its excitation in the invariant nπ+ mass spectrum of the pp → npπ+ reaction at M ≈ 1360 MeV with a width of ≈ 150 MeV . The values fit very favorably to the most recent phase shift results as well as to the observations at BES. In the near-threshold two-pion production pp → ppπ0π0 , where the Roper excitation and its subsequent decays via the routes N * → Δπ → Nππ and N * → Nσ are the only dominant processes, we find its direct decay into the Nσ channel to be the by far dominating decay process --in favor of a monopole excitation of the Roper resonance.

Published
2008

36. Measurement of the exclusive D(p, e+e−)3He and D(p, γ)3He reactions at 98 and 176 MeV

Author

J. C. S. Bacelar, Nasser Kalantar-Nayestanaki, M. Seip, R. Johansson, H. Huisman, Thomas B. Bright, Bo Höistad, J. G. Messchendorp, Göran Fäldt, and E. Traneus

Subjects
Nuclear reaction, Nuclear physics, Physics, Nuclear and High Energy Physics, Photon, Medium energy, Spectrometer, Deuterium, Resolution (electron density), Virtual particle, Atomic physics
Abstract

A high resolution magnetic pair spectrometer for medium energy photons has been used for studies of the exclusive (p,e(+)e(-)) and (p, gamma) reactions on deuterium at 98 and 176 MeV. The (p, e(+)e(-)) cross sections, obtained at 40 degrees and 80 degrees, are compared with the corresponding data for the (p, gamma) reaction measured with the same apparatus. At small virtual photon masses the (p, e(+)e(-)) cross sections show significant enhancement over what is expected from model calculations, a behaviour which has earlier been observed also for the B-11(p, e(+)e(-))C-12 reaction. (C) 1998 Elsevier Science B.V.

Published
1998

37. Pionic D-wave effects in pp→ppπ0 near threshold

Author

A. Turowiecki, J. Zabierowski, Andrzej Kupsc, W. Brodowski, Leif Gustafsson, A. Zernov, S. Häggström, H. Clement, G. J. Wagner, K. Kilian, R. Bilger, A. Sukhanov, Jozef Zlomanczuk, Arne Johansson, A. Mörtsell, B. Morosov, Roger Ruber, U. Schuberth, W. Oelert, B. Shwartz, J. Stepaniak, Bo Höistad, Pawel Marciniewski, Z. Wilhelmi, S. Kullander, Göran Fäldt, Colin Wilkin, C. Ekström, J. Dyring, Hans Calén, Kjell Fransson, and T. Johansson

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Near threshold, Cross section (physics), Pion, Angular distribution, Nuclear Theory, Isotropy, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Beam energy
Abstract

The angular distribution of neutral pions produced in the pp --> pp pi(0) reaction has been measured at a beam energy of 310 MeV. Significant deviations from isotropy are found, which increase f ...

Published
1998

38. Subthreshold Production of Low MomentumK+inp+Cat 1.2 GeV

Author

A. Palmeri, Lars Westerberg, Roberto Barbera, J. Zlomaczhuk, Aldo Bonasera, A. C. Russo, M. Bassi, J. Johansson, V. B. Dunin, A. Badalà, G.V. Russo, F. Librizzi, Curt Ekstrom, Bo Höistad, Göran Ericsson, Marisa Gulino, Francesco Riggi, Tord Johansson, G. S. Pappalardo, A. Sibirtsev, A. Mascali, and R. Turrisi

Subjects
Scattering cross-section, Physics, Spectrometer, Subthreshold conduction, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, Nuclear physics, Momentum, chemistry, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Carbon
Abstract

The double differential cross section of low momentum kaons (less than or equal to 0.3 GeV/c) from p + C collisions at subthreshold bombarding energies has been for the first time measured by the use of the CLAMSUD magnetic spectrometer installed at the C

Published
1998

39. Upper limits for a narrow dibaryon in pp collisions at 200 and 310 MeV

Author

J. Dyring, A. Sukhanov, U. Schuberth, C. Ekström, A. Kupść, A. Turowiecki, H. Clement, S. Häggström, T. Johansson, B. Morosov, B. Shwartz, J. Stepaniak, S. Kullander, Hans Calén, J. Zabierowski, W. Oelert, R. Bilger, K. Kilian, Kjell Fransson, Jozef Zlomanczuk, A. Mörtsell, A. Zernov, G. J. Wagner, Pawel Marciniewski, Z. Wilhelmi, Arne Johansson, Bo Höistad, W. Brodowski, Leif Gustafsson, and Roger Ruber

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Bremsstrahlung, Quantum number, Storage ring
Abstract

Dibaryons, forbidden by mass to decay into NN π channel and by quantum numbers into NN channel, may still have escaped detection. In fact, recently an observation of a narrow dibaryon (D) with the mass close to 1920 MeV was reported in the process pp → γγ + X . This dibaryon should also appear in the proton-proton bremsstrahlung data from measurements at 200 and 310 MeV, which have been carried out at the CELSIUS storage ring in Uppsala. From these data upper limits of 10 and 3 nb are obtained for the dibaryon production cross section (at 95% confidence level) for the two energies, respectively.

Published
1998

40. CELSIUS as an η factory

Author

A. Martemyanov, G. J. Wagner, V. Tikhomirov, Hans Calén, M. Gornov, H. Clement, J. Moehn, B. Morosov, Kjell Fransson, Akira Yamamoto, A. Nawrot, W. Oelert, G. M. Kolachev, R. Bilger, J. Zabierowski, A.E. Bondar, A. Turowiecki, Roger Ruber, S. Dahlgren, W. Brodowski, B. Shwartz, J. Stepaniak, Pawel Marciniewski, Yu. B. Gurov, S. Sandukovsky, A. Zernov, V. Tchernyshev, Z. Pawlowski, A. A. Kuznetsov, Leif Gustafsson, Andrzej Kupsc, D. Reistad, A. Povtorejko, T. Johansson, Y. Yuasa, K. Kilian, M. Komogorov, Bo Höistad, L. Komogorova, V.A. Sidorov, T. Purlatz, R. Shafigullin, V. B. Dunin, Hiromi Hirabayashi, I. Chuvilo, A. Jansson, M. Blom, Z. Wilhelmi, B. Chernyshev, V. Sopov, S. Häggström, C.-J. Fridén, S. Kullander, A.I. Sukhanov, H. Ikegami, Jozef Zlomanczuk, Y. Mizuno, A. Kuzmin, D. Bogoslawsky, Arne Johansson, A. Yamaoka, and C. Ekström

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Degree Celsius, Factory (object-oriented programming), High Energy Physics::Experiment, Nuclear Experiment, Ring (chemistry), Physics::Atmospheric and Oceanic Physics, Storage ring
Abstract

The WASA project at the CELSIUS storage ring is being prepared for high-luminosity experiments to study rare decays of light mesons, in particular the η meson. The CELSIUS ring together with the newly developed pellet target will serve as an efficient η factory.

Published
1997

41. Radiative proton capture to discrete states in 31N at 98 and 176 MeV

Author

Stephen R. Cotanch, R. Johansson, E. Traneus, Bo Höistad, and Thomas B. Bright

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Photon, Proton, Excited state, Shell (structure), Radiative transfer, Tensor, Atomic physics, Ground state
Abstract

A high resolution magnetic pair spectrometer for medium energy photons has been used for studies of the exclusive (p,γ) reaction on 12 C at 98 and 176 MeV. We present angular distributions of the differential cross section for transitions to the ground state and the first three excited states of 13 N. The distributions from these four states are compared with predictions from a microscopic continuum shell model calculation using a realistic finite-ranged effective interaction with tensor components. In general, reasonable agreement is obtained for reactions to states described by p shell single particle wave functions, but poor agreement is obtained for transitions described by sd shell single particle wave functions. Nevertheless we find, however, that the dominant reaction mechanism is a direct capture process. We also compare the (p,γ) data with existing data on the exclusive (p,π) reaction at 185 MeV revealing notable differences between the two reactions.

Published
1997

42. First measurement of the exclusive (p, e+e−) reaction

Author

R. Johansson, Thomas B. Bright, E. Traneus, G. S. Adams, J.E. Thun, and Bo Höistad

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Virtual particle, Electron, Momentum, medicine.anatomical_structure, Excited state, medicine, Invariant mass, Atomic physics, Nuclear Experiment, Ground state, Nucleus
Abstract

We present the first data on the exclusive ( p , e + e − ) reaction in a nucleus. Cross sections for populating the ground state and first excited state in the residual nucleus are presented for the reaction 11 B( p , e + e − ) 12 C at 98 MeV. The e + e − momentum vectors were measured with a high-resolution magnetic pair spectrometer. The distributions of the virtual photon invariant mass and of the direction of the electron in the virtual photon rest system are compared with a simple single-nucleon model. The ( p , e + e − ) cross sections are compared with corresponding data for the ( p , γ ) reaction obtained with the same apparatus. The ( p , e + e − ) cross sections show substantial enhancement over what is expected from the simple model.

Published
1997

43. A search for deeply bound pionic states of xenon produced in the 136Xe(d, 3He)135Xeπ-bound reaction

Author

K. Lindberg, P.-E. Tegnér, B. A. Chernyshev, R. Shafigullin, Chr. Bargholtz, Yu. B. Guro, V. G. Sandukovsky, Bo Höistad, I. V. Laukhin, L. Geren, and V. Grebenev

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Xenon-135, Binding energy, Population, chemistry.chemical_element, Elementary particle, Atomic and Molecular Physics, and Optics, Xenon, chemistry, Helium-3, Bound state, Atomic physics, education
Abstract

A search for deeply bound pionic states of xenon produced in the 136Xe(d, 3He)135Xeπ-bound reaction at Ed = 500 MeV is reported. The population of the 1s pionic-atom state of 135Xe is observed on the predicted level of the cross section ∼ 40 μb/sr. The binding energy of the 1s state, B = 2.9 ± 0.5 MeV, however, is lower than theoretically predicted.

Published
2005

44. 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

45. 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

46. Isospin decomposition of the basic double-pionic fusion in the region of the ABC effect

Author

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

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Particle physics, fusion, +deuteron+2pi%22">p nucleon --> deuteron 2pi, Meson, Gev-C, two-pion [mass spectrum], Nuclear Theory, Hadron, isovector, FOS: Physical sciences, Elementary particle, Juelich COSY PS, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, ABC effect and resonance structure, isoscalar, 0103 physical sciences, Pi, Nuclear fusion, Collisions, ddc:530, Meson Production, Nuclear Experiment (nucl-ex), WASA, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Double Pion Production, mass enhancement, Pp, energy dependence [channel cross section], Total Cross-Sections, isospin decomposition, p n, Abc Effect And Resonance Structure, double pion production, Isospin, fusion [p p], pair production [pi], Lsospin Decomposition, experimental results
Abstract

Exclusive and kinematically complete high-statistics measurements of the basic double-pionic fusion reactions $pn\rightarrow d\pi ^{0}\pi ^{0}, pn\rightarrow d\pi ^{+}\pi ^{-}$ and $pp\rightarrow d\pi ^{+}\pi ^{0}$ have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the $d\pi ^{0}\pi ^{0}$ channel exhibits the ABC effect, i.e. a low-mass enhancement in the $\pi \pi$ - invariant mass distribution, as well as the associated resonance structure in the total cross section, the isovector part given by the $d\pi ^{+}\pi ^{-}$ channel shows a smooth behavior consistent with the conventional t -channel $\Delta \Delta$ process. The $d\pi^{+}\pi ^{-}$ data are very well reproduced by combining the data for isovector and isoscalar contributions, if the kinematical consequences of the isospin violation due to different masses for charged and neutral pions are taken into account.

Published
2013

47. Search for narrow NN-decoupled resonances in the πNN-system — an overview

Author

B. Shwartz, J. Stepaniak, A. Denig, Tord Johansson, S. Häggström, K. Föhl, W. Kluge, U. Siodlaczek, R. Wieser, Jozef Zlomanczuk, G. Kurz, J. Möhn, D. Schapler, Staffan Carius, M. Schepkin, Roger Ruber, A. Mörtsell, K. Kilian, A. Kupść, Hans Calén, C. Ekström, Leif Gustafsson, Kjell Fransson, G.J. Wagner, Promice Collabaration, J. Zabierowski, U. Schuberth, S. Kullander, D. Reistad, R. Bilger, A. Zernov, V. Renken, W. Brodowski, W. Oelert, A. Sukhanov, H. Clement, Arne Johansson, Bo Höistad, and B. Morosov

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Nuclear Theory, Resonance, Context (language use), Nuclear Experiment, Charge exchange
Abstract

The status of the search for NN-decoupled resonances in the πNN-system is reviewed. After a short survey on the history of dibaryon searches reactions suitable for detecting such resonances are discussed. Special emphasis is put on the pionic double charge exchange, where recently evidence for the signature of a narrow πNN resonance, called d ′, with I ( J P ) = even (0 − ) and m = 2.06 GeV has been quoted. Further reactions discussed in this context are the pion photoproduction on the deuteron and the two-pion production in nucleon-nucleon collisions.

Published
1996

48. The pp → ppπ0 reaction near the kinematical threshold

Author

Staffan Carius, C. Ekström, Arne Johansson, A.E. Bondar, A. Kupść, M. Waters, K. Kilian, Leif Gustafsson, Z. Wilhelmi, D. Reistad, S. Häggström, B. Morosov, Bo Höistad, Roger Ruber, A. Kuzmin, B. Shwartz, J. Stepaniak, Tord Johansson, Hans Calén, U. Schuberth, V. Tchernyshev, S. Sandukovsky, J. Zabierowski, A. Povtorejko, A. Mörtsell, Kjell Fransson, S. Kullander, J. Zlomanczuk, A. Sukhanov, and W. Oelert

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Photon, Spectrometer, Nuclear Theory, Dalitz plot, Scintillator, Nuclear physics, Invariant mass, Atomic physics, Nuclear Experiment, Storage ring, Event reconstruction
Abstract

The pp → ppη reaction has been measured at six energies close to threshold, from 1258 MeV to 1352 MeV, using an internal cluster gas jet target in the CELSIUS storage ring. The η is detected through its decay photons, in an array of CsI detectors, and the forward-going protons are detected in a plastic scintillator spectrometer. A complete event reconstruction is obtained at the higher energies in the measured interval. The new data, together with earlier data, give an accurate determination of the energy dependence close to threshold. The influence of the η-proton FSI is seen in the total cross section data as well as in a Dalitz plot of the η-p invariant mass distributions.

Published
1995

49. 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
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50. A Trigger System based on fast sampling ADCs - implementation and tests

Author

T. Johansson, L. Heijkenskojld, V. Hejny, Magnus Wolke, Hans Calén, Kjell Fransson, Harald Kleines, Jozef Zlomanczuk, Andrzej Kupsc, P. Wuestner, W. Erven, P. Plucinski, Pawel Marciniewski, Bo Höistad, and D. Coderre

Subjects
Programmable logic device, Data acquisition, Sampling (signal processing), business.industry, Computer science, Nuclear electronics, Detector, Electrical engineering, business, Field-programmable gate array, Computer hardware, Energy (signal processing), Event reconstruction
Abstract

A Trigger System for a multi-detector setup is presented. The system takes advantage of the newly developed continuous-sampling 16-channel, 12-bit, 160-Msps ADC modules. The ADCs are equipped with programmable logic (FPGA) and perform on-line digital “charge” integration, resolve pile-ups and compute arrival times of detector signals with an accuracy of 1.5 ns. A fast trigger data lane connects the ADC units to a Trigger Module using optical links. Each Trigger Module features 16 optical interfaces (SFP) running at 2 Gb/s input data rate and can be used for evaluating trigger decisions or as a DAQ unit. The Trigger system was implemented in the WASA@COSY experiment, performing on-line event reconstruction, including complex detector calibration, delivering triggers based on multiplicity of tracks fulfilling deposited energy, scattering angle and ΔE/E criteria. Depending on the trigger algorithm used, the trigger latency measured from the actual detector signal to the trigger output amounts to 1.3 – 1.5 µs.

Published
2011

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