Author: "Klaja, J." - Searchworks@Jio Institute Digital Library Search Results

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131 results on '"Klaja, J."'

1. Determination of the eta'-proton scattering length in free space

Author: Czerwinski, E., Moskal, P., Silarski, M., Bass, S. D., Grzonka, D., Kamys, B., Khoukaz, A., Klaja, J., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Smyrski, J., Taschner, A., Wolke, M., and Zielinski, M.
Subjects: Nuclear Experiment
Abstract: Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton-beam of the Cooler Synchrotron COSY we determine the excitation function for the pp --> pp eta' reaction close-to-threshold. Combining these data with previous results we extract the scattering length for the eta'-proton potential in free space to be Re(a_{p eta'}) = 0+-0.43 fm and Im(a_{p eta'}) = 0.37(+0.40)(-0.16) fm., Comment: 5 pages, 3 figures, accepted for publication in Phys. Rev. Lett
Published: 2014
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2. Measurement of the $pn \to pp\pi^0\pi^-$ Reaction in Search for the Recently Observed Resonance Structure in $d\pi^0\pi^0$ and $d\pi^+\pi^-$ systems

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berłowski, M., Bhatt, H., Büscher, M., Calén, H., Ciepał, I., Clement, H., Coderre, D., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C. --O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Wagner, G. J., Węglorz, W., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., Żuprański, P., and Żurek, M.
Subjects: Nuclear Experiment
Abstract: Exclusive measurements of the quasi-free $pn \to pp\pi^0\pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $\sqrt s$ = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. No ABC effect, {\it i.e.} low-mass enhancement is found in the $\pi^0\pi^-$-invariant mass spectrum -- in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s-wave. At the upper end of the covered energy region $t$-channel processes for Roper, $\Delta(1600)$ and $\Delta\Delta$ excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at $m$=~2.37 GeV with $\Gamma$ =~70 MeV and $I(J^P)=~0(3^+)$ observed recently in $pn \to d\pi^0\pi^0$ and $pn \to d\pi^+\pi^-$ reactions leads to an agreement with the data also at low energies.
Published: 2013
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3. Investigation of the dd -> 3He n \pi 0 reaction with the FZ J\'ulich WASA-at-COSY facility

Author: Collaboration, WASA-at-COSY, Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berłowski, M., Bhatt, H., Büscher, M., Calén, H., Ciepał, I., Clement, H., Coderre, D., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C. --O., Hanhart, C., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Wagner, G. J., Węglorz, W., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., Żuprański, P., and Żurek, M.
Subjects: Nuclear Experiment
Abstract: An exclusive measurement of the dd -> 3He n \pi 0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on a combination of a quasi-free model and a partial wave expansion for three-body reaction. The total cross section is found to be \sigma(tot) = (2.89 +- 0.01(stat) +- 0.06(sys) +- 0.29(norm)) \mu b. The contribution of the quasi-free processes (with the neutron being target or beam spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of the phase space. The remaining part of the cross section can be described within a partial wave decomposition indicating the significance of p-wave contributions in the final state., Comment: 9 pages, 7 figures
Published: 2013
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4. Search for a dark photon in the $\pi^0 \to e^+e^-\gamma$ decay

Author: Collaboration, WASA-at-COSY, Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berłowski, M., Bhatt, H., Bondar, A., Büscher, M., Calén, H., Ciepał, I., Clement, H., Coderre, D., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C. -O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Kuzmin, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Meißner, U. -G., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Shwartz, B., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Wagner, G. J., Wȩglorz, W., Wirzba, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Zabierowski, J., Zieliński, M. J., Zipper, W., Złomańczuk, J., Żuprański, P., and Żurek, M.
Subjects: High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Experiment
Abstract: The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the pp-->pp\pi^0 reaction was carried out. An upper limit on the square of the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained for the mass range 20 MeV
Published: 2013
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5. Search for the eta-mesic 4He with WASA-at-COSY detector

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calen, H., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullstroem, C. -O., Hauenstein, F., Heijkenskjoeld, L., Hejny, V., Hinterberger, F., Hodana, M., Hoeistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Marianski, B., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Ozerianska, I., del Rio, E. Perez, Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wolke, M., Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, J., Zupranski, P., and Zurek, M.
Subjects: Nuclear Experiment
Abstract: An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta meson production in the dd->4He-eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the 4He-eta system varied from -51.4MeV to 22MeV. The integrated luminosity in the experiment was determined using the dd->3Hen reaction. The shape of the excitation function for the dd->3Heppi- was examined. No signal of the 4He-eta bound state was observed. An upper limit for the cross-section for the bound state formation and decay in the process dd->(4He-eta)bound->3Heppi- was determined on the 90% confidence level and it varies from 20nb to 27nb for the bound state width ranging from 5MeV to 35MeV, respectively., Comment: 8 pages, 9 figures
Published: 2013
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6. Isospin Decomposition of the Basic Double-Pionic Fusion in the Region of the ABC Effect

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Büscher, M., Calen, H., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullstrom, C. -O., Hauenstein, F., Heijkenskjol, L., Hejny, V., Hinterberger, F., Hodana, M., Hoistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Marianski, B., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Ozerianska, I., del Rio, E. Perez, Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Wkeglorz, W., Wolke, M., Wronska, A., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, J., Zupranski, P., and Zurek, M.
Subjects: Nuclear Experiment, High Energy Physics - Experiment
Abstract: Exclusive and kinematically complete high-statistics measurements of the basic double pionic fusion reactions pn -> dpi0pi0, pn -> d pi+pi- and pp -> dpi+pi0 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 dpi0pi0 channel exhibits the ABC effect, i.e. a low-mass enhancement in the pipi-invariant mass distribution, as well as the associated resonance structure in the total cross section, the isovector part given by the dpi+pi0 channel shows a smooth behavior consistent with the conventional t-channel Delta Delta process. The dpi+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: 2012
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7. ABC Resonance Structure in the Double-Pionic Fusion to 4He

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Brinkmann, K. T., Buescher, M., Calen, H., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullstroem, C. O., Hauenstein, F., Heijkenskjold, L., Hejny, V., Hinterberger, F., Hodana, M., Hoistad, B., Husmann, C., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krzemien, W., Kulessa, P., Kupsc, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Marianski, B., Mikirtychiants, M., Morsch, H. P., Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Ozerianska, I., Pauly, C., del Rio, E. Perez, Petukhov, Y., Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Serdyuk, V., Shah, N., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Wkeglorz, W., Wolke, M., Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, J., and Zupranski, P.
Subjects: Nuclear Experiment, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract: Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction $dd \to ^4$He$\pi^0\pi^0$ have been performed in the energy range 0.8 - 1.4 GeV covering thus the region of the ABC 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 COSY. Similar to the observation in the basic $pn \to d \pi^0\pi^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. The maximum occurs at m=2.37 GeV + 2$m_N$, i.e. at the same position as in the basic reaction. The observed resonance width $\Gamma \approx$ 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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8. Exclusive Measurement of the eta --> pi+ pi- gamma Decay

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berłowski, M., Bhatt, H., Brinkmann, K. -T., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, C. -O., Hanhart, C., Heijkenskjöld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Leupold, S., Lorentz, B., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Meißner, U. -G., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Nandi, B. K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petri, T., Petukhov, Y., Piskunov, N., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Pyszniak, A., Rausmann, T., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stollenwerk, F., Szczurek, A., Täschner, A., Terschlüsen, C., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G. J., Węglorz, W., Winnemöller, A., Wirzba, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., and Żuprański, P.
Subjects: Nuclear Experiment, High Energy Physics - Experiment
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 --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected differential distributions have been extracted based on 13340\pm140 events after background subtraction. The measured pion angular distribution is consistent with a relative p-wave of the two-pion system, whereas the measured photon energy spectrum was found at variance with the simplest gauge invariant matrix element of eta --> pi+ pi- gamma. A parameterization of the data can be achieved by the additional inclusion of the empirical pion vector form factor multiplied by a first-order polynomial in the squared invariant mass of the pi+ pi- system., Comment: 7 pages, 10 figures, submitted to Phys.Lett.B
Published: 2011
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9. \pi^0 \pi^0 Production in Proton-Proton Collisions at Tp=1.4 GeV

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berłowski, M., Bhatt, H., Brinkmann, K. --T., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryevj, K., Gullström, C. --O., Heijkenskjöld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lorentz, B., Machner, H., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, C. F., Ritman, J., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Szczurek, A., Täschner, A., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wiedner, U., Winnemöller, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., and Zuprański, P.
Subjects: High Energy Physics - Experiment
Abstract: The reaction pp->pppi0pi0 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_normalization) mub. In order to to study the production mechanism, differential kinematical distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found, Comment: Submitted to PLB
Published: 2011
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10. ABC Effect in Basic Double-Pionic Fusion --- Observation of a new resonance?

Author: Adlarson, P., Adolph, C., Augustyniak, W., Baru, V., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bhatt, H., Brinkmann, K. -T., Buescher, M., Calen, H., Clement, H., Coderre, D., Czerwinski, E., Doroshkevich, E., Ekstrom, C., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Grishina, V., Gullstrom, C. -O., Hampe, J., Hanhart, C., Heijkenskj, L., Hejny, V., Hinterberger, F., Hodana, M., Hoistad, B., Jacewicz, M., Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Jaus, J., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Kren, F., Krzemien, W., Kulessa, P., Kullander, S., Kupsc, A., Lalwani, K., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Marianski, B., Mikirtychiants, M., Moskal, P., Morsch, H. -P., Nandi, B. K., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Plucinski, P., Podkopal, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, C. F., Ritman, J., Roy, A., Ruber, R. J. M. Y., Rudy, Z., Schadmand, S., Schmidt, A., Schroeder, W., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Taeschner, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Winnemoeller, A., Wirzba, A., Wolke, M., Wronska, A., Wuestner, P., Wurm, P., Yurev, L., Zabierowski, J., Zielinski, M. J., Zipper, W., Zlomanczuk, J., and Zupranski, P.
Subjects: Nuclear Experiment
Abstract: We report on a high-statistics measurement of the basic double pionic fusion reaction $pn \to d\pi^0\pi^0$ over the energy region of the so-called ABC effect, a pronounced low-mass enhancement in the $\pi\pi$-invariant mass spectrum. The measurements were performed with the WASA detector setup at COSY. The data reveal the ABC effect to be associated with a Lorentzian shaped energy dependence in the integral cross section. The observables are consistent with a resonance with $I(J^P) =0(3^+)$ in both $pn$ and $\Delta\Delta$ systems. Necessary further tests of the resonance interpretation are discussed.
Published: 2011
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11. Studies of properties of the eta' meson at the COSY-11 facility

Author: Czerwinski, E., Klaja, J., Klaja, P., and Moskal, P.
Subjects: Nuclear Experiment
Abstract: We shortly discuss results on the isospin dependence of the eta-prime production cross section in nucleon-nucleon collisions, results of comparative analysis of the invariant mass distributions for the pp-->pp eta-prime and pp-->pp eta reactions, and we present the value of the total width of the eta-prime meson as derived directly from the mass distribution measured with the mass resolution of 0.3~MeV/c^2., Comment: 2 pages, presented at 11th International Workshop On Meson Production, Properties And Interaction (MESON 2010) 10-15 Jun 2010, Cracow, Poland
Published: 2010
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12. Determination of the total width of the eta' meson

Author: Czerwinski, E., Moskal, P., Grzonka, D., Czyzykiewicz, R., Gil, D., Kamys, B., Khoukaz, A., Klaja, J., Klaja, P., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taschner, A., Wolke, M., Wustner, P., Zdebik, J., Zielinski, M., and Zipper, W.
Subjects: Nuclear Experiment
Abstract: Taking advantage of both the low-emittance proton-beam of the Cooler Synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the eta' meson was measured with a resolution of 0.33 MeV/c^2 (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp --> pp eta' events the total width of the eta' meson was determined to be 0.226 +- 0.017(stat.) +- 0.014(syst.) MeV/c^2., Comment: 4 pages, 4 figures
Published: 2010
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13. Studies of properties of the eta-prime meson at the COSY-11 facility

Author: Czerwinski, E., Klaja, J., Klaja, P., and Moskal, P.
Subjects: Nuclear Experiment
Abstract: We shortly discuss results on the isospin dependence of the eta-prime production cross section in nucleon-nucleon collisions, results of comparative analysis of the invariant mass distributions for the pp-->pp eta-prime and pp-->pp eta reactions, and we present the value of the total width of the eta-prime meson as derived directly from the mass distribution measured with the mass resolution of 0.3 MeV/c^2., Comment: This paper has been withdrawn by the author, since it is published as arXiv:1009.548 [nucl-ex]
Published: 2010

14. Study of the eta-prime meson structure, width and interactions with nucleons at COSY-11

Author: Czerwiński, E., Klaja, J., Klaja, P., and Moskal, P.
Subjects: Nuclear Experiment
Abstract: We present results on the isospin dependence of the eta-prime production cross section in nucleon-nucleon collisions, as well as the results of comparative analysis of the invariant mass distributions for the pp-->pp eta-prime and pp-->pp eta reactions in the context of the proton-eta and proton-eta-prime interaction. Additionally, the value of the total width of the eta-prime is reported as derived directly from the measurement of the mass distribution and an explanation of the experimental technique used in order to achieve a precision about an order of magnitude better then former experiments is included., Comment: 8 pages, 4 figures, presented at Excited QCD 2010 conference (31 January-6 February 2010) Tatra National Park (Slovakia)
Published: 2010

15. Upper limit of the total cross section for the pn --> pn eta' reaction

Author: Klaja, J., Moskal, P., Bass, S. D., Czerwinski, E., Czyzykiewicz, R., Gil, D., Grzonka, D., Johansson, T., Kamys, B., Khoukaz, A., Klaja, P., Krzemien, W., Oelert, W., Rejdych, B., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taschner, A., Wolke, M., Wustner, P., Zdebik, J., Zielinski, M., and Zipper, W.
Subjects: Nuclear Experiment
Abstract: The upper limit of the total cross section for the pn --> pn eta' reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R_eta' = sigma(pn --> pn eta') / sigma(pp --> pp eta') with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta' meson and suggests nonidentical production mechanisms for eta and eta' mesons.
Published: 2010
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16. Two-proton correlation function for the pp -> pp+eta and pp -> pp+pions reactions

Author: Klaja, P., Moskal, P., Czerwinski, E., Czyzykiewicz, R., Deloff, A., Gil, D., Grzonka, D., Kamys, B., Khoukaz, A., Klaja, J., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taeschner, A., Wolke, M., Zdebik, J., Zielinski, M., and Zipper, W.
Subjects: Nuclear Experiment
Abstract: For the very first time, the correlation femtoscopy method is applied to a kinematically complete measurement of meson production in the collisions of hadrons. A two-proton correlation function was derived from the data for the pp -> ppX reaction, measured near the threshold of eta meson production. A technique developed for the purpose of this analysis permitted to establish the correlation function separately for the production of the pp+eta and of the pp+pions systems. The shape of the two-proton correlation function for the ppeta differs from that for the pp(pions) and both do not show a peak structure opposite to results determined for inclusive measurements of heavy ion collisions.
Published: 2010
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17. Measurement of the invariant mass distributions for the pp -> ppeta' reaction at excess energy of Q = 16.4 MeV

Author: Klaja, P., Moskal, P., Czerwinski, E., Czyzykiewicz, R., Deloff, A., Gil, D., Grzonka, D., Jarczyk, L., Kamys, B., Khoukaz, A., Klaja, J., Nakayama, K., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taeschner, A., Wolke, M., Zdebik, J., Zielinski, M., and Zipper, W.
Subjects: Nuclear Experiment
Abstract: The proton-proton and proton-eta' invariant mass distributions have been determined for the pp -> ppeta' reaction at an excess energy of Q = 16.4 MeV. The measurement was carried out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the pp -> ppeta reaction and reveal an enhancement for large relative proton-proton momenta. This result, together with the fact that the proton-eta interaction is much stronger that the proton-eta' interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson.
Published: 2010
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18. Invariant mass distributions for the pp to p p eta reaction at Q=10 MeV

Author: Moskal, P., Czyzykiewicz, R., Czerwinski, E., Gil, D., Grzonka, D., Jarczyk, L., Kamys, B., Khoukaz, A., Klaja, J., Klaja, P., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taschner, A., Wolke, M., Wustner, P., Zdebik, J., Zielinski, M. J., and Zipper, W.
Subjects: Nuclear Experiment
Abstract: Proton-proton and proton-eta invariant mass distributions and the total cross section for the pp to pp eta reaction have been determined near the threshold at an excess energy of Q=10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q=15.5 MeV and Q= 40MeV., Comment: 6 pages, 3 figures, submitted to Eur.Phys. J. A
Published: 2009
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19. Isospin dependence of the eta-prime meson production in collisions of nucleons

Author: Klaja, J.
Subjects: Nuclear Experiment
Abstract: The upper limit of the total cross section for quasi-free pn -> pn eta-prime reaction has been determined in the excess energy range near the kinematic threshold. The measurement has been carried out at the COSY-11 detection setup using a proton beam and a deuteron cluster target. The identification of the eta-prime meson has been performed using the missing mass technique. The energy dependence of the upper limit of the cross section is extracted with a fixed proton beam momentum of p_beam}=3.35GeV/c and exploiting the Fermi momenta of nucleons inside the deuteron. The data cover a range of centre-of-mass excess energies from 0 to 24 MeV. The experimentally determined upper limit of the ratio R(eta-prime)=sigma(pn -> pn eta-prime) sigma(pp -> pp eta-prime), which is smaller than the ratio for the eta meson, excludes the excitation of the S_11(1535) resonance as a dominant production mechanism of the eta-prime meson in nucleon-nucleon collisions. At the same time, the determined upper limits of R(eta-prime) go in the direction of what one would expect in the glue production and production via mesonic currents. For quantitative tests of these mechanisms an order of magnitude larger statistics and a larger energy range would be required. This can be reached with the WASA-at-COSY facility., Comment: Ph.D.Thesis (Advisor: Prof. Pawel Moskal), 2009
Published: 2009

20. Generalized Dalitz Plot analysis of the near threshold pp-->ppK+K- reaction in view of the K+K- final state interaction

Author: Silarski, M., Moskal, P., Czerwinski, E., Czyzykiewicz, R., Gil, D., Grzonka, D., Jarczyk, L., Kamys, B., Khoukaz, A., Klaja, J., Klaja, P., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Smyrski, J., Taschner, A., Winter, P., Wolke, M., Wustner, P., Zielinski, M., Zipper, W., and Zdebik, J.
Subjects: High Energy Physics - Phenomenology
Abstract: The excitation function for the $pp\to ppK^+K^-$ reaction revealed a significant enhancement close to threshold which may plausibly be assigned to the influence of the $pK^-$ and $K^+K^-$ final state interactions. In an improved reanalysis of COSY-11 data for the $pp\to ppK^+K^-$ reaction at excess energies of Q = 10 MeV and 28 MeV including the proton-K- interaction the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK+K- system as derived from the COSY-ANKE data. Finally, based for the first time on the low energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be |Re(a_K^+K^-)| = 0.5 + 4.0 -0.5 fm and Im(a_K^+K^-) = 3.0 +- 3.0 fm., Comment: 8 pages, 7 figures, to be published in Phys. Rev. C
Published: 2009
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21. Study of the near threshold total cross sesctions for the quasi-free pn-->pn eta prime reaction with the COSY-11 detector

Author: Klaja, J., Moskal, P., and Zdebik, J.
Subjects: Nuclear Experiment
Abstract: The measurement of the quasi-free production of the eta prime meson has been carried out at the COSY-11 detection setup using a proton beam and a deuteron cluster target. The energy dependence of the cross section is extracted using a fixed proton beam momentum of p_beam=3.35 GeV/c and exploiting the Fermi momenta of nucleons inside deuterons. The data cover a range of centre-of-mass excess energies from 0 to 24 MeV. Due to the low statistics at the present stage only upper limits for the cross sections could be extracted. In this article we focus on the functioning and efficiency determination of the neutron detector., Comment: Presented at the Symposium on Meson Physics, Cracow, 01-04 October 2008
Published: 2009

22. Invariant-mass distributions for the pp $ \eta$ reaction at Q = 10 MeV

Author: Moskal, P., Czyżykiewicz, R., Czerwiński, E., Gil, D., Grzonka, D., Jarczyk, L., Kamys, B., Khoukaz, A., Klaja, J., Klaja, P., Krzemień, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Täschner, A., Wolke, M., Wüstner, P., Zdebik, J., Zieliński, M. J., and Zipper, W.
Published: 2010
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23. NMR laboratory measurements of various types of sedimentary rocks using 2, and 23 MHz spectrometers

Author: Klaja, J., Drabik, K., Dohnlik, M., and Kulinowski, P.
Published: 2017

24. Determination of the ${\eta }^{\prime }$-Proton Scattering Length in Free Space

Author: Czerwiński, E., Moskal, P., Ritman, J., Sefzick, T., Smyrski, J., Täschner, A., Wolke, M., Zieliński, M., Silarski, M., Bass, S. D., Grzonka, D., Kamys, B., Alfons Khoukaz, Klaja, J., Krzemień, W., and Oelert, W.
Subjects: ddc:550, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Astrophysics::Galaxy Astrophysics
Abstract: Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton beam of the cooler synchrotron COSY, we determine the excitation function for the pp→ppη′ reaction close to threshold. Combining these data with previous results, we extract the scattering length for the η′-proton potential in free space to be Re(apη′)=0±0.43 fm and Im(apη′)=0.37+0.40−0.16 fm.
Published: 2014

25. Search for a dark photon in the [formula omitted] decay

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F.S., Berłowski, M., Bhatt, H., Bondar, A., Büscher, M., Calén, H., Ciepał, I., Clement, H., Coderre, D., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C.-O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jany, A., Jany, B.R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F.A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kirillov, D.A., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Kuzmin, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Meißner, U.-G., Mikirtychiants, M., Morsch, H.-P., Moskal, P., Nandi, B.K., Ohm, H., Ozerianska, I., Perez del Rio, E., Piskunov, N.M., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C.F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Shwartz, B., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Wagner, G.J., Wȩglorz, W., Wirzba, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Zabierowski, J., Zieliński, M.J., Zipper, W., Złomańczuk, J., Żuprański, P., and Żurek, M.
Published: 2013
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26. Isospin decomposition of the basic double-pionic fusion in the region of the ABC effect

Author: Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F.S., Berłowski, M., Bhatt, H., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C.-O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jany, A., Jany, B.R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F.A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Mikirtychiants, M., Morsch, H.-P., Moskal, P., Nandi, B.K., Niedźwiecki, S., Ohm, H., Ozerianska, I., Perez del Rio, E., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C.F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G.J., Węglorz, W., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M.J., Zipper, W., Złomańczuk, J., Żuprański, P., and Żurek, M.
Published: 2013
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27. Search for a dark photon in the $\pi^0 \to e^+e^-\gamma$ decay

Author: Adlarson, P., Augustyniak, W., Ciepal, I., Trzcinski, A., Varma, R., Wagner, G. J., Weglorz, W., Wirzba, Andreas, Wolke, Magnus, Wronska, A., Wüstner, Peter, Wurm, Patrick, Yamamoto, A., Clement, H., Zabierowski, J., Zielinski, M. J., Zipper, W., Zlomanczuk, J., Zupranski, P., Zurek, M., Coderre, Daniel, Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, Ralf W., Erven, Wilhelm, Eyrich, W., Fedorets, Pavel, Bardan, W., Föhl, K., Fransson, K., Goldenbaum, Frank, Goslawski, P., Goswami, Ankita, Grigoryev, Kirill, Gullström, C. -O., Hauenstein, Florian, Heijkenskjöld, L., Hejny, Volker, Bashkanov, M., Hinterberger, F., Hodana, Malgorzata, Höistad, B., Jany, A., Jany, Benedykt, Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, Günter, Khan, Farha Anjum, Bergmann, F. S., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, Harald, Kirillov, D. A., Klos, B., Krapp, M., Krzemien, W., Kulessa, Pawel, Kupsc, Andrzej, Berlowski, M., Kuzmin, A., Lalwani, K., Lersch, Daniel, Li, L., Lorentz, Bernd, Magiera, A., Maier, Rudolf, Marciniewski, P., Marianski, B., Meißner, Ulf-G., Bhatt, Himani, Mikirtychyants, Maxim, Morsch, H. -P., Moskal, Pawel, Nandi, B. K., Ohm, Henner, Ozerianska, I., Perez del Rio, E., Piskunov, N. M., Plucinski, P., Podkopal, P., Bondar, A., Prasuhn, Dieter, Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, F., Ritman, James, Roy, A., Rudy, Z., Sawant, S., Büscher, Markus, Schadmand, Susan, Schmidt, A., Sefzick, Thomas, Serdyuk, Valeriy, Shah, N., Shwartz, B., Siemaszko, M., Siudak, R., Skorodko, T., Skruzok, M., Calen, Hans, Smyrski, J., Sopov, V., Stassen, Rolf, Stepaniak, J., Stephan, E., Sterzenbach, Guenter, Stockhorst, Hans, Stroeher, Hans, Szczurek, A., and Tolba, T.
Subjects: branching ratio: upper limit [pi0], +positron+electron+photon%22">pi0 --> positron electron photon, 0.55 GeV-kin, radiative decay [pi0], interaction [p p], Juelich COSY PS, High Energy Physics - Experiment, High Energy Physics - Phenomenology, magnetic moment [muon], +2p+pi0%22">p p --> 2p pi0, ddc:530, High Energy Physics::Experiment, WASA, Nuclear Experiment, mixing [photon], search for [U boson], mass spectrum [electron positron], experimental results, +U+boson+photon%22">pi0 --> U boson photon
Abstract: The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the pp-->pp\pi^0 reaction was carried out. An upper limit on the square of the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained for the mass range 20 MeV, Comment: 16 pages, 8 figures; improved analysis extending the exclusion region to 20 MeV
Published: 2013

28. Investigation of the dd -> (3)Hen pi(0) reaction with the FZ Julich WASA-at-COSY facility

Author: ADLARSON, P, AUGUSTYNIAK, W, BARDAN, W, BASHKANOV, M, BERGMANN, FS, BERLOWSKI, M, BHATT, H, BUSCHER, M, CALEN, H, CIEPAL, I, CLEMENT, H, CODERRE, D, CZERWINSKI, E, DEMMICH, K, DOROSHKEVICH, E, ENGELS, R, ERVEN, W, EYRICH, W, FEDORETS, P, FOHL, K, FRANSSON, K, GOLDENBAUM, F, GOSLAWSKI, P, GOSWAMI, A, GRIGORYEV, K, GULLSTROM, CO, HANHART, C, HAUENSTEIN, F, HEIJKENSKJOLD, L, HEJNY, V, HINTERBERGER, F, HODANA, M, HOISTAD, B, JANY, A, JANY, BR, JARCZYK, L, JOHANSSON, T, KAMYS, B, KEMMERLING, G, KHAN, FA, KHOUKAZ, A, KIRILLOV, DA, KISTRYN, S, KLAJA, J, KLEINES, H, KLOS, B, KRAPP, M, KRZEMIEN, W, KULESSA, P, KUPSC, A, LALWANI, K, LERSCH, D, LI, L, LORENTZ, B, MAGIERA, A, MAIER, R, MARCINIEWSKI, P, MARIANSKI, B, MIKIRTYCHIANTS, M, MORSCH, HP, MOSKAL, P, NANDI, BK, OHM, H, OZERIANSKA, I, DEL RIO, EP, PISKUNOV, NM, PLUCINSKI, P, PODKOPAL, P, PRASUHN, D, PRICKING, A, PSZCZEL, D, PYSZ, K, PYSZNIAK, A, REDMER, CF, RITMAN, J, ROY, A, RUDY, Z, SAWANT, S, SCHMIDT, A, SCHADMAND, S, SEFZICK, T, SERDYUK, V, SHAH, N, SIEMASZKO, M, SIUDAK, R, SKORODKO, T, SKURZOK, M, SMYRSKI, J, SOPOV, V, STASSEN, R, STEPANIAK, J, STEPHAN, E, STERZENBACH, G, STOCKHORST, H, STROHER, H, SZCZUREK, A, TOLBA, T, TRZCINSKI, A, VARMA, R, WAGNER, GJ, WEGLORZ, W, WOLKE, M, WRONSKA, A, WUSTNER, P, WURM, P, YAMAMOTO, A, YUAN, X, ZABIEROWSKI, J, ZHENG, C, ZIELINSKI, MJ, ZIPPER, W, ZLOMANCZUK, J, ZUPRANSKI, P, and ZUREK, M
Subjects: Threshold, Quark Masses
Abstract: An exclusive measurement of the dd -> (3)Hen pi(0) reaction was carried out at a beam momentum of p(d) = 1.2 GeV/c using the WASA-at-COSY facility. Information on the total cross section as well as differential distributions was obtained. The data are described by a phenomenological approach based on a combination of a quasifree model and a partial wave expansion for the three-body reaction. The total cross section is found to be sigma(tot) = ( 2.89 +/- 0.01(stat) +/- 0.06(sys) +/- 0.29(norm)) mu b. The contribution of the quasifree processes ( with the beam or target neutron being a spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of phase space. The remaining part of the cross section can be described by a partial wave decomposition indicating the significance of p-wave contributions in the final state.
Published: 2013
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29. Search for eta-mesic He-4 with the WASA-at-COSY detector

Author: ADLARSON, P, AUGUSTYNIAK, W, BARDAN, W, BASHKANOV, M, BEDNARSKI, T, BERGMANN, FS, BERLOWSKI, M, BHATT, H, BUSCHER, M, CALEN, H, CLEMENT, H, CODERRE, D, CZERWINSKI, E, DEMMICH, K, DOROSHKEVICH, E, ENGELS, R, ERVEN, W, EYRICH, W, FEDORETS, P, FOHL, K, FRANSSON, K, GOLDENBAUM, F, GOSLAWSKI, P, GOSWAMI, A, GRIGORYEV, K, GULLSTROM, CO, HAUENSTEIN, F, HEIJKENSKJOLD, L, HEJNY, V, HINTERBERGER, F, HODANA, M, HOISTAD, B, JANY, A, JANY, BR, JARCZYK, L, JOHANSSON, T, KAMYS, B, KEMMERLING, G, KHAN, FA, KHOUKAZ, A, KISTRYN, S, KLAJA, J, KLEINES, H, KLOS, B, KRAPP, M, KRZEMIEN, W, KULESSA, P, KUPSC, A, LALWANI, K, LERSCH, D, LI, L, LORENTZ, B, MAGIERA, A, MAIER, R, MARCINIEWSKI, P, MARIANSKI, B, MIKIRTYCHIANTS, M, MORSCH, HP, MOSKAL, P, NANDI, BK, NIEDZWIECKI, S, OHM, H, OZERIANSKA, I, DEL RIO, EP, PLUCINSKI, P, PODKOPAL, P, PRASUHN, D, PRICKING, A, PSZCZEL, D, PYSZ, K, PYSZNIAK, A, REDMER, CF, RITMAN, J, ROY, A, RUDY, Z, SAWANT, S, SCHADMAND, S, SCHMIDT, A, SEFZICK, T, SERDYUK, V, SHAH, N, SIEMASZKO, M, SIUDAK, R, SKORODKO, T, SKURZOK, M, SMYRSKI, J, SOPOV, V, STASSEN, R, STEPANIAK, J, STEPHAN, E, STERZENBACH, G, STOCKHORST, H, STROHER, H, SZCZUREK, A, TOLBA, T, TRZCINSKI, A, VARMA, R, VLASOV, P, WAGNER, GJ, WEGLORZ, W, WOLKE, M, WRONSKA, A, WUSTNER, P, WURM, P, YAMAMOTO, A, YUAN, X, YUREV, L, ZABIEROWSKI, J, ZHENG, C, ZIELINSKI, MJ, ZIPPER, W, ZLOMANCZUK, J, ZUPRANSKI, P, and ZUREK, M
Subjects: Photoproduction, Mesons, Bound-States, Nuclei
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 taken during a slow acceleration of the beam from 2.185 to 2.400 GeV/c crossing the kinematic threshold for the eta-meson production in the dd -> He-4 eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the He-4-eta system varied from -51.4 to 22 MeV. The integrated luminosity in the experiment was determined using the dd -> (3)Hen reaction. The shape of the excitation function for the dd -> (3)Hep pi(-) reaction was examined. No signal of the He-4-eta bound state was observed. An upper limit for the cross section for the bound state formation and decay in the process dd -> (He-4-eta)(bound) -> (3)Hep pi(-) was determined on the 90% confidence level and it varies from 20 to 27 nb for the bound state width ranging from 5 to 35 MeV, respectively. DOI: 10.1103/PhysRevC.87.035204
Published: 2013

30. Measurement of the pn→ppπ0π− reaction in search for the recently observed resonance structure in dπ0π0 and dπ+π− systems

Author: Adlarson, P., Augustyniak, W., Clement, H., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Coderre, D., Złomańczuk, J., Żuprański, P., Żurek, M., Czerwiński, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Bardan, W., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C. -O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Bashkanov, M., Hodana, M., Höistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, Günter, Khan, F. A., Khoukaz, A., Bergmann, F. S., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Berłowski, M., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Bhatt, H., Nandi, B. K., Ohm, H., Ozerianska, I., Perez del Rio, E., Piskunov, N. M., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Büscher, M., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Calen, Hans, Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Ciepał, I., Stephan, E., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Wagner, G. J., and Węglorz, W.
Subjects: effective Lagrangian, Nuclear Theory, polarized beam [photon], amplitude analysis, exclusive reaction [photon nucleon], associated production [omega(783)], threshold, ddc:530, momentum transfer [differential cross section], +N%281440%29+omega%28783%29%22">photon nucleon --> N(1440) omega(783), photoproduction [N(1440)], Nuclear Experiment, asymmetry [spin], numerical calculations
Abstract: Associative photoproduction of $\omega$-meson and $N^{*}(1440)$ on nucleons, $\gamma+N\to\omega+N^{*}(1440)$, in the near threshold region is investigated in a framework employing effective Lagrangians. Besides $\pi$-exchange in t-channel, baryon exchanges, i.e. N- and $N^{*}$-exchanges, in the s- and u-channels are also taken into account in calculations of differential cross-section and beam asymmetry. Important inputs of this model are the vector and tensor coupling constants of $\omega NN^{*}(1440)$-vertex, which are assumed to be equal to the values of these couplings for $\omega NN$ vertex. Using our previous estimation of $\omega NN$ coupling constants obtained from a fit to available experimental data on photoproduction of $\omega$ meson in the near threshold region, we produce the necessary numerical predictions for different observables in $\gamma+N\to\omega+N^{*}(1440)$. Numerical results shows that at low $|$t$|$ dominant contribution comes from t-channel $\pi$-exchange while effects of nucleon and $N^{*}(1440)$ pole terms can be seen at large $|t|$. Our predictions for the differential cross section and beam asymmetry for the processes $\gamma+N\to\omega+N^{*}(1440)$, where N is proton and neutron at $E_{\gamma}=2.5$ GeV are presented with zero width approximation and also with the inclusion of width effects of $N^{*}(1440)$.
Published: 2013

31. Investigation of the dd -> 3He n ��0 reaction with the FZ J��lich WASA-at-COSY facility

Author: COSY Collaboration, Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Ber��owski, M., Bhatt, H., B��scher, M., Cal��n, H., Ciepa��, I., Clement, H., Coderre, D., Czerwi��ski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., F��hl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullstr��m, C. --O., Hanhart, C., Hauenstein, F., Heijkenskj��ld, L., Hejny, V., Hinterberger, F., Hodana, M., H��istad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., K��os, B., Krapp, M., Krzemie��, W., Kulessa, P., Kup��, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Maria��ski, B., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Pluci��ski, P., Podkopa��, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Str��her, H., Szczurek, A., Tolba, T., Trzci��ski, A., Varma, R., Wagner, G. J., W��glorz, W., Wolke, M., Wro��ska, A., W��stner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zieli��ski, M. J., Zipper, W., Z��oma��czuk, J., ��upra��ski, P., and ��urek, M.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: An exclusive measurement of the dd -> 3He n ��0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on a combination of a quasi-free model and a partial wave expansion for three-body reaction. The total cross section is found to be ��(tot) = (2.89 +- 0.01(stat) +- 0.06(sys) +- 0.29(norm)) ��b. The contribution of the quasi-free processes (with the neutron being target or beam spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of the phase space. The remaining part of the cross section can be described within a partial wave decomposition indicating the significance of p-wave contributions in the final state., 9 pages, 7 figures
Published: 2013
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32. Search for a dark photon in the $��^0 \to e^+e^-��$ decay

Author: COSY Collaboration, Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Ber��owski, M., Bhatt, H., Bondar, A., B��scher, M., Cal��n, H., Ciepa��, I., Clement, H., Coderre, D., Czerwi��ski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., F��hl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullstr��m, C. -O., Hauenstein, F., Heijkenskj��ld, L., Hejny, V., Hinterberger, F., Hodana, M., H��istad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., K��os, B., Krapp, M., Krzemie��, W., Kulessa, P., Kup��, A., Kuzmin, A., Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Maria��ski, B., Mei��ner, U. -G., Mikirtychiants, M., Morsch, H. -P., Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N., Pluci��ski, P., Podkopa��, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Shwartz, B., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Str��her, H., Szczurek, A., Tolba, T., Trzci��ski, A., Varma, R., Wagner, G. J., W��glorz, W., Wirzba, A., Wolke, M., Wro��ska, A., W��stner, P., Wurm, P., Yamamoto, A., Zabierowski, J., Zieli��ski, M. J., Zipper, W., Z��oma��czuk, J., ��upra��ski, P., and ��urek, M.
Subjects: High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the pp-->pp��^0 reaction was carried out. An upper limit on the square of the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained for the mass range 20 MeV, 16 pages, 8 figures; improved analysis extending the exclusion region to 20 MeV
Published: 2013
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33. Search for η-mesic ^{4}He with the WASA-at-COSY detector

Author: Adlarson, P., Augustyniak, W., Clement, H., Wüstner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., Coderre, D., Żuprański, P., Żurek, M., Engels, Ralf W., Stroeher, Hans, Czerwiński, E., Demmich, K., Doroshkevich, E., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Bardan, W., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, C. –O., Hauenstein, F., Heijkenskjöld, L., Hejny, V., Hinterberger, F., Hodana, M., Bashkanov, M., Höistad, B., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Bednarski, T., Klaja, J., Kleines, H., Kłos, B., Krapp, M., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lersch, D., Li, L., Bergmann, F. S., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Mariański, B., Mikirtychiants, M., Morsch, H. –P., Moskal, P., Nandi, B. K., Niedźwiecki, S., Berłowski, M., Ohm, H., Ozerianska, I., Perez del Rio, E., Pluciński, P., Podkopał, P., Prasuhn, D., Pricking, A., Pszczel, D., Pysz, K., Pyszniak, A., Bhatt, H., Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Büscher, M., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Calén, H., Stockhorst, H., Szczurek, A., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G. J., Węglorz, W., Wolke, M., and Wrońska, A.
Subjects: High Energy Physics::Experiment, ddc:530, Nuclear Experiment
Abstract: An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta meson production in the dd->4He-eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the 4He-eta system varied from -51.4MeV to 22MeV. The integrated luminosity in the experiment was determined using the dd->3Hen reaction. The shape of the excitation function for the dd->3Heppi- was examined. No signal of the 4He-eta bound state was observed. An upper limit for the cross-section for the bound state formation and decay in the process dd->(4He-eta)bound->3Heppi- was determined on the 90% confidence level and it varies from 20nb to 27nb for the bound state width ranging from 5MeV to 35MeV, respectively.
Published: 2013

34. Exclusive measurement of the [formula omitted] decay

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F.S., Berłowski, M., Bhatt, H., Brinkmann, K.-T., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, C.-O., Hanhart, C., Heijkenskjöld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Jany, A., Jany, B.R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Leupold, S., Lorentz, B., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Meißner, U.-G., Mikirtychiants, M., Morsch, H.-P., Moskal, P., Nandi, B.K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., Perez del Rio, E., Petri, T., Petukhov, Y., Piskunov, N., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Pyszniak, A., Rausmann, T., Redmer, C.F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stollenwerk, F., Ströher, H., Szczurek, A., Täschner, A., Terschlüsen, C., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G.J., Węglorz, W., Winnemöller, A., Wirzba, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M.J., Zipper, W., Złomańczuk, J., and Żuprański, P.
Published: 2012
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35. [formula omitted] Production in proton–proton collisions at [formula omitted]

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F.S., Berłowski, M., Bhatt, H., Brinkmann, K.-T., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, C.-O., Heijkenskjöld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Janusz, M., Jany, A., Jany, B.R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lorentz, B., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Mikirtychiants, M., Morsch, H.-P., Moskal, P., Nandi, B.K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., Perez del Rio, E., Petukhov, Y., Piskunov, N., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, C.F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Ströher, H., Szczurek, A., Täschner, A., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G.J., Węglorz, W., Wiedner, U., Winnemöller, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M.J., Zipper, W., Złomańczuk, J., and Żuprański, P.
Published: 2012
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36. pi^0 pi^0 Production in Proton-Proton Collisions at Tp=1.4 GeV

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berłowski, M., Bhatt, H., Brinkmann, K. --T., Büscher, M., Calén, H., Clement, H., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryevj, K., Gullström, C. --O., Heijkenskjöld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Lalwani, K., Lorentz, B., Machner, H., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, C. F., Ritman, J., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Szczurek, A., Täschner, A., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wiedner, U., Winnemöller, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M. J., Zipper, W., Złomańczuk, J., and Zuprański, P.
Subjects: Nuclear Theory, High Energy Physics::Experiment, ddc:530, Nuclear Experiment, High Energy Physics - Experiment
Abstract: The reaction pp->pppi0pi0 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_normalization) mub. In order to to study the production mechanism, differential kinematical distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found, Comment: Submitted to PLB
Published: 2012

37. Exclusive measurement of the η→ $\pi^+ \pi^-$ γ decay

Author: Adlarson, P., Adolph, C., Büscher, M., Szczurek, A., Täschner, A., Terschlüsen, C., Tolba, T., Trzciński, A., Varma, R., Vlasov, P., Wagner, G. J., Węglorz, W., Winnemöller, A., Calén, H., Wirzba, A., Wolke, M., Wrońska, A., Wüstner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieliński, M. J., Clement, H., Zipper, W., Złomańczuk, J., Żuprański, P., Coderre, D., Czerwiński, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Augustyniak, W., Föhl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, C.-O., Hanhart, C., Heijkenskjöld, L., Heimlich, J., Hejny, V., Bardan, W., Hinterberger, F., Hodana, M., Höistad, B., Jacewicz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Bashkanov, M., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Kłos, B., Kren, F., Krzemień, W., Kulessa, P., Kupść, A., Bednarski, T., Lalwani, K., Leupold, S., Lorentz, B., Magiera, A., Maier, R., Mariański, B., Marciniewski, P., Meißner, U.-G., Mikirtychiants, M., Morsch, H.-P., Bergmann, F. S., Moskal, P., Nandi, B. K., Niedźwiecki, S., Ohm, H., Passfeld, A., Pauly, C., Perez del Rio, E., Petri, T., Petukhov, Y., Piskunov, N., Berłowski, M., Pluciński, P., Podkopał, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Pyszniak, A., Rausmann, T., Redmer, C. F., Ritman, J., Bhatt, H., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Brinkmann, K.-T., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stollenwerk, F., and Ströher, H.
Subjects: hadroproduction [eta], +helium+eta%22">p deuteron --> helium eta, gauge [invariance], Juelich COSY PS, momentum [beam], energy spectrum [photon], radiative decay [eta], 1.7 GeV/c, vector [form factor], (pi+ pi- photon) [mass spectrum], angular distribution [pi], High Energy Physics::Experiment, ddc:530, +pi%2B+pi-+photon%22">eta --> pi+ pi- photon, Nuclear Experiment, fusion [p deuteron], experimental results
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 --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected differential distributions have been extracted based on 13340\pm140 events after background subtraction. The measured pion angular distribution is consistent with a relative p-wave of the two-pion system, whereas the measured photon energy spectrum was found at variance with the simplest gauge invariant matrix element of eta --> pi+ pi- gamma. A parameterization of the data can be achieved by the additional inclusion of the empirical pion vector form factor multiplied by a first-order polynomial in the squared invariant mass of the pi+ pi- system.
Published: 2012

38. pi(0)pi(0) Production in proton-proton collisions at T-p=1.4 GeV The WASA-at-COSY Collaboration

Author: ADLARSON, P, ADOLPH, C, AUGUSTYNIAK, W, BASHKANOV, M, BEDNARSKI, T, BERGMANN, FS, BERLOWSKI, M, BHATT, H, BRINKMANN, KT, BUSCHER, M, CALEN, H, CLEMENT, H, CODERRE, D, CZERWINSKI, E, DOROSHKEVICH, E, ENGELS, R, ERVEN, W, EYRICH, W, FEDORETS, P, FOHL, K, FRANSSON, K, GOLDENBAUM, F, GOSLAWSKI, P, GRIGORYEV, K, GULLSTROM, CO, HEIJKENSKJOLD, L, HEIMLICH, J, HEJNY, V, HINTERBERGER, F, HODANA, M, HOISTAD, B, JACEWICZ, M, JANUSZ, M, JANY, A, JANY, BR, JARCZYK, L, JOHANSSON, T, KAMYS, B, KEMMERLING, G, KHAKIMOVA, O, KHOUKAZ, A, KISTRYN, S, KLAJA, J, KLEINES, H, KLOS, B, KREN, F, KRZEMIEN, W, KULESSA, P, KUPSC, A, LALWANI, K, LORENTZ, B, MAGIERA, A, MAIER, R, MARIANSKI, B, MARCINIEWSKI, P, MIKIRTYCHIANTS, M, MORSCH, HP, MOSKAL, P, NANDI, BK, NIEDZWIECKI, S, OHM, H, PASSFELD, A, PAULY, C, DEL RIO, EP, PETUKHOV, Y, PISKUNOV, N, PLUCINSKI, P, PODKOPAL, P, POVTOREYKO, A, PRASUHN, D, PRICKING, A, PYSZ, K, RAUSMANN, T, REDMER, CF, RITMAN, J, ROY, A, RUDY, Z, SAWANT, S, SCHADMAND, S, SCHMIDT, A, SEFZICK, T, SERDYUK, V, SHAH, N, SIEMASZKO, M, SKORODKO, T, SKURZOK, M, SMYRSKI, J, SOPOV, V, STASSEN, R, STEPANIAK, J, STERZENBACH, G, STOCKHORST, H, STROHER, H, SZCZUREK, A, TASCHNER, A, TOLBA, T, TRZCINSKI, A, VARMA, R, VLASOV, P, WAGNER, GJ, WEGLORZ, W, WIEDNER, U, WINNEMOLLER, A, WOLKE, M, WRONSKA, A, WUSTNER, P, WURM, P, YUAN, X, YUREV, L, ZABIEROWSKI, J, ZHENG, C, ZIELINSKI, MJ, ZIPPER, W, ZLOMANCZUK, J, and ZUPRANSKI, P
Subjects: Roper Resonance, Pion Production, Pp, Cross-Sections, 2-Pion Production, Excitation, Model
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(normalization)) mu b. In order to study the production mechanism, differential kinematic distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found. (C) 2011 Elsevier B.V. All rights reserved.
Published: 2012

39. ��^0 ��^0 Production in Proton-Proton Collisions at Tp=1.4 GeV

Author: Adlarson, P., Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Ber��owski, M., Bhatt, H., Brinkmann, K. --T., B��scher, M., Cal��n, H., Clement, H., Coderre, D., Czerwi��ski, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., F��hl, K., Fransson, K., Goldenbaum, F., Goslawski, P., Grigoryevj, K., Gullstr��m, C. --O., Heijkenskj��ld, L., Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., H��istad, B., Jacewicz, M., Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., K��os, B., Kren, F., Krzemie��, W., Kulessa, P., Kup��, A., Lalwani, K., Lorentz, B., Machner, H., Magiera, A., Maier, R., Maria��ski, B., Marciniewski, P., Mikirtychiants, M., Morsch, H. --P., Moskal, P., Nandi, B. K., Nied��wiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Pluci��ski, P., Podkopa��, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, C. F., Ritman, J., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Szczurek, A., T��schner, A., Tolba, T., Trzci��ski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wiedner, U., Winnem��ller, A., Wolke, M., Wro��ska, A., W��stner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zieli��ski, M. J., Zipper, W., Z��oma��czuk, J., and Zupra��ski, P.
Subjects: High Energy Physics - Experiment (hep-ex), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The reaction pp->pppi0pi0 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_normalization) mub. In order to to study the production mechanism, differential kinematical distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found, Submitted to PLB
Published: 2011
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40. Study of the eta-prime meson structure, width and interactions with nucleons at COSY-11

Author: Czerwi��ski, E., Klaja, J., Klaja, P., and Moskal, P.
Subjects: Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We present results on the isospin dependence of the eta-prime production cross section in nucleon-nucleon collisions, as well as the results of comparative analysis of the invariant mass distributions for the pp-->pp eta-prime and pp-->pp eta reactions in the context of the proton-eta and proton-eta-prime interaction. Additionally, the value of the total width of the eta-prime is reported as derived directly from the measurement of the mass distribution and an explanation of the experimental technique used in order to achieve a precision about an order of magnitude better then former experiments is included., 8 pages, 4 figures, presented at Excited QCD 2010 conference (31 January-6 February 2010) Tatra National Park (Slovakia)
Published: 2010

41. Two-proton correlation function for the pp to pp eta and pp to pp pions reactions

Author: Klaja, P., Moskal, P., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Täschner, A., Wolke, M., Zdebik, J., Czerwinksi, E., Zielinski, M., Zipper, W., Czyzykiewicz, R., Deloff, A., Gil, D., Grzonka, D., Kamys, B., Alfons Khoukaz, and Klaja, J.
Subjects: ddc:530
Published: 2010

42. Upper limit of the total cross section for the pn to pn eta' reaction

Author: Klaja, J., Moskal, P., Bass, S. D., Czerwinski, E., Czyzykiewicz, R., Gil, D., Grzonka, D., Johansson, T., Kamys, B., Khoukaz, A., Klaja, P., Krzemien, W., Oelert, W., Rejdych, B., Ritman, J., Sefzick, T., Siemaszko, M., Silarski, M., Smyrski, J., Taschner, A., Wolke, M., Wustner, P., Zdebik, J., Zielinski, M., and Zipper, W.
Subjects: +p+n+eta%28958%29%22">p n --> p n eta(958), Nuclear Theory, High Energy Physics::Experiment, ddc:530, correlation function, Nuclear Experiment, hadroproduction [eta(958)], upper limit [cross section]
Abstract: The upper limit of the total cross section for the pn --> pn eta' reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R_eta' = sigma(pn --> pn eta') / sigma(pp --> pp eta') with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta' meson and suggests nonidentical production mechanisms for eta and eta' mesons.
Published: 2010

43. Study of the ${\eta }'$ meson structure, width and interactions with nucleons at COSY-11

Author: Eryk Czerwiński, Klaja, J., Klaja, P., and Moskal, P.
Published: 2010

44. Measurement of the eta -> 3 pi(0) Dalitz plot distribution with the WASA detector at COSY

Author: ADOLPH, C, ANGELSTEIN, M, BASHKANOV, M, BECHSTEDT, U, BELOSTOTSKI, S, BERLOWSKI, M, BHATT, H, BISPLINGHOFF, J, BONDAR, A, BORASOY, B, BUSCHER, M, SCOBEL, W, SEFZICK, T, SERDYUK, V, SHAH, N, SIEMASZKO, M, SIUDAK, R, SKORODKO, T, SMOLINSKI, T, SMYRSKI, J, SOPOV, V, CALEN, H, SPOLGEN, D, STEPANIAK, J, STERZENBACH, G, STROHER, H, SZCZUREK, A, TEUFEL, A, TOLBA, T, TRZCINSKI, A, ULBRICH, K, VARMA, R, CHANDWANI, K, VLASOV, P, WEGLORZ, W, WINNEMOLLER, A, WIRZBA, A, WOLKE, M, WRONSKA, A, WUSTNER, R, XU, H, YAMAMOTO, A, YAMAOKA, H, CLEMENT, H, YUAN, X, YUREV, L, ZABIEROWSKI, J, ZHENG, C, ZIELINSKI, MJ, ZIPPER, W, ZLOMANCZUK, J, ZWOLL, K, ZYCHOR, I, CZERWINSKI, E, CZYZYKIEWICZ, R, D'ORSANEO, G, DUNIEC, D, EKSTROM, C, ENGELS, R, ERVEN, W, EYRICH, W, FEDORETS, P, FELDEN, O, FRANSSON, K, GIL, D, GOLDENBAUM, F, GRIGORYEV, K, HECZKO, A, HANHART, C, HEJNY, V, HINTERBERGER, F, HODANA, M, HOISTAD, B, IZOTOV, A, JACEWICZ, M, JANUSZ, M, JANY, BR, JARCZYK, L, JOHANSSON, T, KAMYS, B, KEMMERLING, G, KESHELASHVILI, I, KHAKIMOVA, O, KHOUKAZ, A, KILIAN, K, KIMURA, N, KISTRYN, S, KLAJA, J, KLAJA, P, KLEINES, H, KLOS, B, KOWALCZYK, A, KREN, F, KRZEMIEN, W, KULESSA, P, KULLANDER, S, KUPSC, A, KUZMIN, A, KYRYANCHUK, V, MAJEWSKI, J, MACHNER, H, MAGIERA, A, MAIER, R, MARCINIEWSKI, R, MIGDAL, W, MEISSNER, UG, MIKIRTYCHIANTS, M, MIKLUKHO, O, MILKE, N, MITTAG, M, MOSKAL, P, NANDI, BK, NAWROT, A, NISSLER, R, ODOYO, MA, OELERT, W, OHM, H, PAUL, N, PAULY, C, PETUKHOV, Y, PISKUNOV, N, PLUCINSKI, P, PODKOPAL, P, POVTOREYKO, A, PRASUHN, D, PRICKING, A, PYSZ, K, RACHOWSKI, J, RAUSMANN, T, REDMER, CF, RITMAN, J, ROY, A, RUBER, RJMY, RUDY, Z, SALMIN, R, SCHADMAND, S, SCHMIDT, A, SCHNEIDER, H, and SCHROEDER, W
Subjects: Current-Algebra, Performance, Dalitz plot, Nuclear Theory, hadronic decay [eta], 1.4 GeV, interaction [p p], final-state interaction [pi pi], Juelich COSY PS, +2p+eta%22">p p --> 2p eta, eta, Final-State Interactions, +3+pi%280%29%22">eta -> 3 pi(0), Chiral Perturbation-Theory, +3+Pi%280%29%22">Eta -> 3 Pi(0), Channels, 3-Pi%22">Eta->3-Pi, ddc:530, Nuclear Experiment, Daq System, hadroproduction [eta], Eta, Pi-Pi Scattering, Electromagnetic Corrections, slope [Dalitz plot], Dalitz Plot, High Energy Physics::Experiment, Decays, +3pi0%22">eta --> 3pi0
Abstract: In the first production run of the WASA experiment at COSY, the eta decay into three neutral pions was measured in proton-proton interactions at a proton beam kinetic energy of 1.4 GeV. The Dalitz plot of the three pions was studied using 1.2e5 fully reconstructed events, and the quadratic slope parameter alpha was determined to be -0.027+/-0.008(stat)+/-0.005(syst). The result is consistent with previous measurements and further corroborates the importance of pion-pion final state interactions., Comment: 6 pages, 4 figures, elsarticle
Published: 2009

45. Generalized Dalitz plot analysis of the near-threshold pp -> ppK(+)K(-) reaction in view of the K+K- final state interaction

Author: Silarski, M., Moskal, P., Czerwinski, E., Czyzykiewicz, R., Gil, D., Grzonka, D., Jarczyk, L., Kamys, B., Khoukaz, A., Klaja, J., Klaja, P., Krzemien, W., Oelert, W., Ritman, J., Sefzick, T., Siemaszko, M., Smyrski, J., Taschner, A., Winter, P., Wolke, M., Wustner, P., Zielinski, M., Zipper, W., and Zdebik, J.
Subjects: pair production [K], Dalitz plot, Juelich COSY PS [interpretation of experiments], interaction [p p], enhancement [threshold], energy dependence [channel cross section], magnetic spectrometer, final-state interaction [K- p], scattering length [K+ K-], mass spectrum, +p+p+K%2B+K%22">p p --> p p K+ K, High Energy Physics - Phenomenology, differential cross section, ddc:530, final-state interaction [K+ K-], numerical calculations
Abstract: The excitation function for the $pp\to ppK^+K^-$ reaction revealed a significant enhancement close to threshold which may plausibly be assigned to the influence of the $pK^-$ and $K^+K^-$ final state interactions. In an improved reanalysis of COSY-11 data for the $pp\to ppK^+K^-$ reaction at excess energies of Q = 10 MeV and 28 MeV including the proton-K- interaction the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK+K- system as derived from the COSY-ANKE data. Finally, based for the first time on the low energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be |Re(a_K^+K^-)| = 0.5 + 4.0 -0.5 fm and Im(a_K^+K^-) = 3.0 +- 3.0 fm., Comment: 8 pages, 7 figures, to be published in Phys. Rev. C
Published: 2009

46. Determination of theη′-Proton Scattering Length in Free Space

Author: Czerwiński, E., primary, Moskal, P., additional, Silarski, M., additional, Bass, S. D., additional, Grzonka, D., additional, Kamys, B., additional, Khoukaz, A., additional, Klaja, J., additional, Krzemień, W., additional, Oelert, W., additional, Ritman, J., additional, Sefzick, T., additional, Smyrski, J., additional, Täschner, A., additional, Wolke, M., additional, and Zieliński, M., additional
Published: 2014
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47. Search for eta-mesic He-4 with the WASA-at-COSY detector

Author: Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell, Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Hoistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Ozerianska, I., del Rio, E. Perez, Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, Zupranski, P., Zurek, M., Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell, Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Hoistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Ozerianska, I., del Rio, E. Perez, Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, Zupranski, P., and Zurek, M.
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 taken during a slow acceleration of the beam from 2.185 to 2.400 GeV/c crossing the kinematic threshold for the eta-meson production in the dd -> He-4 eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the He-4-eta system varied from -51.4 to 22 MeV. The integrated luminosity in the experiment was determined using the dd -> (3)Hen reaction. The shape of the excitation function for the dd -> (3)Hep pi(-) reaction was examined. No signal of the He-4-eta bound state was observed. An upper limit for the cross section for the bound state formation and decay in the process dd -> (He-4-eta)(bound) -> (3)Hep pi(-) was determined on the 90% confidence level and it varies from 20 to 27 nb for the bound state width ranging from 5 to 35 MeV, respectively.
Published: 2013
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48. Investigation of the dd -> (3)Hen pi(0) reaction with the FZ Julich WASA-at-COSY facility

Author: Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Ciepal, I., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell E. I., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hanhart, C., Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Wagner, G. J., Weglorz, W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Josef, Zupranski, P., Zurek, M., Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Ciepal, I., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell E. I., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hanhart, C., Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Wagner, G. J., Weglorz, W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Josef, Zupranski, P., and Zurek, M.
Abstract: An exclusive measurement of the dd -> (3)Hen pi(0) reaction was carried out at a beam momentum of p(d) = 1.2 GeV/c using the WASA-at-COSY facility. Information on the total cross section as well as differential distributions was obtained. The data are described by a phenomenological approach based on a combination of a quasifree model and a partial wave expansion for the three-body reaction. The total cross section is found to be sigma(tot) = ( 2.89 +/- 0.01(stat) +/- 0.06(sys) +/- 0.29(norm)) mu b. The contribution of the quasifree processes ( with the beam or target neutron being a spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of phase space. The remaining part of the cross section can be described by a partial wave decomposition indicating the significance of p-wave contributions in the final state.
Published: 2013
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49. Measurement of the pn -> pp pi(0)pi(-) reaction in search for the recently observed resonance structure in d pi(0)pi(0) and d pi(+)pi(-) systems

Author: Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Ciepal, I., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell E. I., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Wagner, G. J., Eglorz, W. W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, Zupranski, P., Zurek, M., Adlarson, Patrik, Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bhatt, H., Buescher, M., Calén, Hans, Ciepal, I., Clement, H., Coderre, D., Czerwinski, E., Demmich, K., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell E. I., Goldenbaum, F., Goslawski, P., Goswami, A., Grigoryev, K., Gullström, Carl-Oscar, Hauenstein, F., Heijkenskjöld, Lena, Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khan, F. A., Khoukaz, A., Kirillov, D. A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Krapp, M., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lersch, D., Li, L., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Ohm, H., Ozerianska, I., del Rio, E. Perez, Piskunov, N. M., Plucinski, P., Podkopal, P., Prasuhn, D., Pricking, A., Pszczel, Damian, Pysz, K., Pyszniak, Andrzej, Redmer, C. F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schmidt, A., Schadmand, S., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Siudak, R., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Tolba, T., Trzcinski, A., Varma, R., Wagner, G. J., Eglorz, W. W., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yamamoto, A., Yuan, X., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, Zupranski, P., and Zurek, M.
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 the cooler synchrotron COSY (Institut fur Kernphysik, Julich). Total and differential cross sections have been obtained covering the energy region root s = (2.35-2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. NoABCeffect, i.e., low-mass enhancement is found in the pi(0)pi(-) -invariant mass spectrum, in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s wave. At the upper end of the covered energy region t-channel processes for Roper, Delta(1600) and Delta Delta excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at m = 2.37 GeV with Gamma = 70 MeV and I (J(P)) = 0(3(+)) observed recently in pn -> d pi(0)pi(0) and pn -> d pi(+)pi(-) reactions leads to an agreement with the data also at low energies.
Published: 2013
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50. pi(0)pi(0) Production in proton-proton collisions at T-p=1.4 GeV The WASA-at-COSY Collaboration

Author: Adlarson, Patrik, Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Brinkmann, K. -T, Buescher, M., Calén, Hans, Clement, H., Coderre, D., Czerwinski, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell, Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, Carl-Oskar, Heijkenskjöld, Lena, Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jacewicz, Marek, Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Kren, F., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lorentz, B., Magiera, A., Maier, R., Marianski, B., Marciniewski, Pawel, Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Plucinski, Pawel, Podkopal, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, Christoph F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Taeschner, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wiedner, U., Winnemoeller, A., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, Zupranski, P., Adlarson, Patrik, Adolph, C., Augustyniak, W., Bashkanov, M., Bednarski, T., Bergmann, F. S., Berlowski, M., Bhatt, H., Brinkmann, K. -T, Buescher, M., Calén, Hans, Clement, H., Coderre, D., Czerwinski, E., Doroshkevich, E., Engels, R., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, Kjell, Goldenbaum, F., Goslawski, P., Grigoryev, K., Gullström, Carl-Oskar, Heijkenskjöld, Lena, Heimlich, J., Hejny, V., Hinterberger, F., Hodana, M., Höistad, Bo, Jacewicz, Marek, Janusz, M., Jany, A., Jany, B. R., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khakimova, O., Khoukaz, A., Kistryn, S., Klaja, J., Kleines, H., Klos, B., Kren, F., Krzemien, W., Kulessa, P., Kupsc, Andrzej, Lalwani, K., Lorentz, B., Magiera, A., Maier, R., Marianski, B., Marciniewski, Pawel, Mikirtychiants, M., Morsch, H. -P, Moskal, P., Nandi, B. K., Niedzwiecki, S., Ohm, H., Passfeld, A., Pauly, C., del Rio, E. Perez, Petukhov, Y., Piskunov, N., Plucinski, Pawel, Podkopal, P., Povtoreyko, A., Prasuhn, D., Pricking, A., Pysz, K., Rausmann, T., Redmer, Christoph F., Ritman, J., Roy, A., Rudy, Z., Sawant, S., Schadmand, S., Schmidt, A., Sefzick, T., Serdyuk, V., Shah, N., Siemaszko, M., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Taeschner, A., Tolba, T., Trzcinski, A., Varma, R., Vlasov, P., Wagner, G. J., Weglorz, W., Wiedner, U., Winnemoeller, A., Wolke, Magnus, Wronska, A., Wuestner, P., Wurm, P., Yuan, X., Yurev, L., Zabierowski, J., Zheng, C., Zielinski, M. J., Zipper, W., Zlomanczuk, Jozef, and Zupranski, P.
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(normalization)) mu b. In order to study the production mechanism, differential kinematic distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found.
Published: 2012
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