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290 results on '"Ehrhardt, K."'

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

Author

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

Subjects
Nuclear Experiment
Abstract

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

Published
2016

3. First Model-Independent Measurement of the Spin Triplet $p\Lambda$ Scattering Length from Final State Interaction in the $\vec{p}p \rightarrow pK^{+}\Lambda$ Reaction

Author

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

Subjects
Nuclear Experiment
Abstract

The $\vec{p}p \rightarrow pK^{+}\Lambda$ reaction has been measured with the COSY-TOF detector at a beam momentum of $2.7\,\mathrm{GeV}/c$. The polarized proton beam enables the measurement of the beam analyzing power by the asymmetry of the produced kaon ($A_N^{K}$). This observable allows the $p\Lambda$ spin triplet scattering length to be extracted for the first time model independently from the final-state interaction in the reaction. The obtained value is $a_{t} = (-2.55 ^{+0.72}_{-1.39} {}_{\textrm{stat.}} \pm 0.6_{\textrm{syst.}} \pm 0.3_{\textrm{theo.}})\mathrm{fm}$. This value is compatible with theoretical predictions and results from model-dependent analyses., Comment: Revised version as accepted for publication in PRC

Published
2016
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4. High precision measurement of the associated strangeness production in proton proton interactions

Author

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

Subjects
Nuclear Experiment
Abstract

A new high precision measurement of the reaction pp -> pK+Lambda at a beam momentum of 2.95 GeV/c with more than 200,000 analyzed events allows a detailed analysis of differential observables and their inter-dependencies. Correlations of the angular distributions with momenta are examined. The invariant mass distributions are compared for different regions in the Dalitz plots. The cusp structure at the N Sigma threshold is described with the Flatt\'e formalism and its variation in the Dalitz plot is analyzed., Comment: accepted for publication in Eur. Phys. J.A

Published
2015

5. Final-State Interactions in the Process pp -> pKLambda

Author

Röder, M., Borodina, E., Clement, H., Doroshkevich, E., Dzhygadlo, R., Ehrhardt, K., Erhardt, A., Eyrich, W., Gast, W., Gillitzer, A., Grzonka, D., Haidenbauer, J., Hanhart, C., Hauenstein, F., Klaja, P., Kober, L., Kilian, K., Krapp, M., Mertens, M., Ritman, J., Roderburg, E., Schroeder, W., Sefzick, T., Sibirtsev, A., Wintz, P., and Wüstner, P.

Subjects
Nuclear Experiment
Abstract

The possibility to determine the pLambda scattering length from the final-state interaction in the reaction pp->pKLambda is investigated experimentally. From a transversely polarized measurement, the K analyzing power (A_N) which, in principle, allows one to extract the spin triplet scattering length is studied. An unexpected energy dependence of the forward/backward symmetric part of A_N is found. The influence of N*-resonances on the pLambda invariant mass spectrum is investigated by exploiting the large acceptance for the process pp->pKLambda->pKppi and is found to be the main source of uncertainty for determining the pLambda scattering length.

Published
2013
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6. On the SigmaN cusp in the pp -> pK+Lambda reaction

Author

El-Samad, S. Abd, Borodina, E., Brinkmann, K. -Th., Clement, H., Doroshkevich, E., Dzhygadlo, R., Ehrhardt, K., Erhardt, A., Eyrich, W., Freiesleben, H., Gast, W., Gillitzer, A., Grzonka, D., Hanhart, C., Hauenstein, F., Klja, P., Kilian, K., Krapp, M., Ritman, J., Roderburg, E., Roeder, M., Schulte-Wissermann, M., Schroeder, W., Sfzick, T., Wagner, G. J., Wintz, P., and Wuestner, P.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Measurements of the $pp \to pK^+\Lambda$ reaction at $T_p$ = 2.28 GeV have been carried out at COSY-TOF. In addition to the $\Lambda p$ FSI and $N^*$ resonance excitation effects a pronounced narrow structure is observed in the Dalitz plot and in its projection on the $p\Lambda$-invariant mass. The structure appears at the $pp \to $N$K^+\Sigma$ threshold and is interpreted as $\Sigma$N cusp effect. The observed width of 20 MeV/$c^2$ is substantially broader than anticipated from previous inclusive measurements. Angular distributions of this cusp structure are shown to be dissimilar to those in the residual $pK^+\Lambda$ channel, but similar to those observed in the $pK^+\Sigma^0$ channel.

Published
2012
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7. The pK0\Sigma+ final state in proton-proton collisions

Author

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

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

This paper reports results from a study of the reaction pp->pK0\Sigma+ at beam momenta of p_{beam} = 2950, 3059, and 3200 MeV/c (excess energies of \epsilon= 126, 161, and 206 MeV). Total cross sections were determined for all energies; a set of differential cross sections (Dalitz plots; invariant mass spectra of all two-body subsystems; angular distributions of all final state particles; distributions in helicity and Jackson frames) are presented for \epsilon= 161 MeV. The total cross sections are proportional to the volume of available three-body phase-space indicating that the transition matrix element does not change significantly in this range of excess energies. It is concluded from the differential data that the reaction proceeds dominantly via the N(1710)P_{11} and/or N(1720)P_{13} resonance(s); N(1650)S_{11} and \Delta(1600)P_{33} could also contribute., Comment: 15 pages, 10 figures

Published
2012
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8. Production of Lambda and Sigma^0 hyperons in proton-proton collisions

Author

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

Subjects
Nuclear Experiment
Abstract

This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross sections are given for both reactions. It is concluded from the measured total cross sections that the high energy limit of the cross section ratio is almost reached at an excess energy of only about 200 MeV. From the differential distributions observed in the overall CMS as well as in the Jackson and helicity frames, a significant contribution of interfering nucleon resonances to the \Lambda production mechanism is concluded while resonant \Sigma^0-production seems to be of lesser importance and takes place only through specific partial waves of the entrance channel. The data also indicate that kaon exchange plays a minor role in the case of \Lambda- but an important role for \Sigma^0-production. Thus the peculiar energy dependence of the \Lambda-to-\Sigma^0 cross section ratio appears in a new light as its explanation requires more than mere differences between the p\Lambda and the p\Sigma^0 final state interaction. The data provide a benchmark for theoretical models already available or yet to come., Comment: 18 pages, 10 figures; accepted by The European Physical Journal A (EPJ A)

Published
2010
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9. Influence of N*-resonances on hyperon production in the channel pp->K+ Lambda p at 2.95, 3.20 and 3.30 GeV/c beam momentum

Author

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

Subjects
Nuclear Experiment
Abstract

Hyperon production in the threshold region was studied in the reaction pp -> K+Lp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at the three different beam momenta of p_beam=2.95, 3.20 and 3.30 GeV/c, corresponding to excess energies of epsilon=204, 285 and 316 MeV, respectively. Total cross-sections were deduced for the three beam momenta to be 23.9+/-0.8 +/-2.0 ub, 28.4+/-1.3 +/-2.2 ub and 35.0+/-1.3 +/-3.0 ub. Differential observables including Dalitz plots were obtained. The analysis of the Dalitz plots reveals a strong influence of the N(1650)-resonance at p_beam=2.95 GeV/c, whereas for the higher momenta an increasing relative contribution of the N(1710)- and/or of the N(1720)-resonance was observed. In addition, the pL-final-state interaction turned out to have a significant influence on the Dalitz plot distribution., Comment: accepted for publication at Physics Letters B; some minor text changes were done; also the scale of the ordinates of figure 9 has been changed

Published
2010
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10. Systematic study of the pp -> pp omega reaction

Author

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

Subjects
Nuclear Experiment
Abstract

A systematic study of the production of omega-mesons in proton-proton-collisions was carried out in a kinematically complete experiment at three excess energies(epsilon= 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum J\"ulich. The total cross section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and, additionally, in Sd at epsilon= 173 MeV. No obvious indication of resonant omega-production via N^*-resonances was found, as proton angular distributions are almost isotropic and invariant mass spectra are compatible with phase space distributions. A dominant role of ^3P_1 and ^1S_0 initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega-p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega-p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process., Comment: 17 pages, 16 figures, accepted for publication in EPJA

Published
2010
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11. On the Production of $\pi^+\pi^+$ Pairs in pp Collisions at 0.8 GeV

Author

El-Samad, S. Abd, Bilger, R., Brinkmann, K. -Th., Clement, H., Dietrich, M., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Geyer, R., Gillitzer, A., Hauffe, J., Hesselbarth, D., Jaekel, R., Jakob, B., Karsch, L., Kilian, K., Kress, J., Kuhlmann, E., Marcello, S., Marwinski, S., Meier, R., Moeller, K., Morsch, H. P., Naumann, L., Ritman, J., Roderburg, E., Schulte-Wissermann, P. Schoenmeier M., Schroeder, W., Stinzing, F., Sun, G. Y., Waechter, J., Wagner, G. J. Wagner M., Weidlich, U., Wilms, A., Wirth, S., Zhang, G., and Zupranski, P.

Subjects
Nuclear Experiment
Abstract

Data accumulated recently for the exclusive measurement of the $pp\to pp\pi^+\pi^-$ reaction at a beam energy of 0.793 GeV using the COSY-TOF spectrometer have been analyzed with respect to possible events from the $pp \to nn\pi^+\pi^+$ reaction channel. The latter is expected to be the only $\pi\pi$ production channel, which contains no major contributions from resonance excitation close to threshold and hence should be a good testing ground for chiral dynamics in the $\pi\pi$ production process. No single event has been found, which meets all conditions for being a candidate for the $pp \to nn \pi^+\pi^+$ reaction. This gives an upper limit for the cross section of 0.16 $\mu$b (90% C.L.), which is more than an order of magnitude smaller than the cross sections of the other two-pion production channels at the same incident energy.

Published
2009
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12. Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

Author

El-Samad, S. Abd, Bilger, R., Brinkmann, K. Th., Clement, H., Dietrich, M., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Geyer, R., Gillitzer, A., Hauffe, J., Hesselbarth, D., Jaekel, R., Jakob, B., Karsch, L., Kilian, K., Kress, J., Kuhlmann, E., Marcello, S., Marwinski, S., Meier, R., Moeller, K., Morsch, H. P., Naumann, L., Ritman, J., Roderburg, E., Schoenmeier, P., Schulte-Wissermann, M., Schroeder, W., Stinzing, F., Sun, G. Y., Waechter, J., Wagner, G. J., Wagner, M., Weidlich, U., Wilms, A., Wirth, S., Zhang, G., and Zupranski, P.

Subjects
Nuclear Experiment
Abstract

The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the $np\pi^+$ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the $pp\pi^0$ channel we find in the $np\pi^+$ channel a strong influence of the $\Delta$ excitation already at this energy close to threshold. In particular we find a $(3 cos^2\Theta + 1)$ dependence in the pion angular distribution, typical for a pure s-channel $\Delta$ excitation and identical to that observed in the $d\pi^+$ channel. Since the latter is understood by a s-channel resonance in the $^1D_2$ $pn$ partial wave, we discuss an analogous scenario for the $pn\pi^+$ channel.

Published
2008
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13. Comparison of Isoscalar Vector Meson Production Cross Sections in Proton-Proton Collisions

Author

collaboration, The COSY-TOF, Abdel-Bary, M., Abdel-Samad, S., Brinkmann, K. -Th., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Gillitzer, A., Hesselbarth, D., Jäkel, R., Karsch, L., Kilian, K., Kuhlmann, E., Marcello, S., Michel, P., Möller, K., Morsch, H. P., Pizzolotto, C., Plettner, Ch., Ritman, J., Roderburg, E., Schönmeier, P., Schroeder, W., Schulte-Wissermann, M., Steinke, M., Sun, G. J., Ullrich, W., Wenzel, R., Wintz, P., Wagner, M., Wilms, A., Wirth, S., and Zupranski, P.

Subjects
Nuclear Experiment
Abstract

The reaction $ pp\to pp\bf \omega$ was investigated with the TOF spectrometer, which is an external experiment at the accelerator COSY (Forschungszentrum J\"ulich, Germany). Total as well as differential cross sections were determined at an excess energy of $93 MeV$ ($p_{beam}=2950 MeV/c$). Using the total cross section of $(9.0\pm 0.7 \pm1.1) \mu b$ for the reaction $ pp\to pp\omega$ determined here and existing data for the reaction $pp\to pp\bf \phi$, the ratio $\mathcal{R}_{\phi/\omega}=\sigma_\phi/\sigma_\omega$ turns out to be significantly larger than expected by the Okubo-Zweig-Iizuka (OZI) rule. The uncertainty of this ratio is considerably smaller than in previous determinations. The differential distributions show that the $\omega$ production is still dominated by S-wave production at this excess energy, however higher partial waves clearly contribute. A comparison of the measured angular distributions for $\omega$ production to published distributions for $\phi$ production at $83 MeV$ shows that the data are consistent with an identical production mechanism for both vector mesons.

Published
2007
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14. Improved study of a possible Theta+ production in the pp -> p K0 sigma+ reaction with the COSY-TOF spectrometer

Author

collaboration, COSY-TOF, Abdel-Bary, M., Abdel-Samad, S., Brinkmann, K. -Th., Castelijns, R., Clement, H., Dietrich, J., Dshemuchadse, S., Dorochkevitch, E., Eyrich, W., Ehrhardt, K., Erhardt, A., Freiesleben, H., Gast, W., Georgi, J., Gillitzer, A., Jaeger, H., Jaekel, R., Karsch, L., Kilian, K., Krapp, M., Kuhlmann, E., Lehmann, A., Morsch, H. P., Paul, N., Pinna, L., Pizzolotto, C., Ritman, J., Roderburg, E., Schadmand, S., Schoenmeier, P., Schulte-Wissermann, M., Schroeder, W., Sefzick, T., Teufel, A., Ucar, A., Ullrich, W., Wenzel, R., Wintz, P., Wuestner, P., and Zupranski, P.

Subjects
High Energy Physics - Experiment
Abstract

The pp -> p K0 Sigma+ reaction was investigated with the TOF spectrometer at COSY at 3.059 GeV/c incident beam momentum. The main objective was to clarify whether or not a narrow exotic S = +1 resnance, the Theta+ pentaquark, is populated at 1.53 GeV/c2 in the K0 p subsystem with a data sample of much higher statistical significance compared to the previously reported data in this channel. An analysis of these data does not confirm the existence of the Theta+ pentaquark. This is expressed as an upper limit for the cross section sigma (pp -> p K0 Sigma+) < 0.15 microbarn at the 95 percent confidence level., Comment: 11 pages, 5 figures

Published
2006
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15. Measurement of polarization observables of the associated strangeness production in proton proton interactions

Author

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

Published
2016
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16. High-precision measurement of the associated strangeness production in proton-proton interactions

Author

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

Published
2016
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18. Differential tissular distribution of Litomosoides sigmodontis microfilariae between microfilaremic and amicrofilaremic mice following experimental infection

Author

Bouchery T., Ehrhardt K., Lefoulon E., Hoffmann W., Bain O., and Martin C.

Subjects
filariasis, Litomosoides sigmodontis, microfilariae, amicrofilaremic, real-time PCR, lungs, liver, spleen, Infectious and parasitic diseases, RC109-216
Abstract

Filariases are caused by onchocercid nematodes that are transmitted by arthropod vectors. More than 180 million people are infected worldwide. Mass drug administration has been set up in many endemic areas to control the parasite burden. Although very successful in limiting microfilarial load, transmission has not been completely interrupted in such areas. A proportion of infected patients with lymphatic filariasis or loiasis are known to be amicrofilaremic, as they do not present microfilariae in their bloodstream despite the presence of adult worms. A mirror status also exists in CBA/Ca mice infected with Litomosoides sigmodontis, the well-established model of filariasis. Using this model, the goal of this study was to determine if the kinetics of blood clearance of microfilariae differed between amicrofilaremic CBA/Ca mice and microfilaremic BALB/c mice. For this purpose, a qPCR approach was devised to detect microfilariae in different tissues, after a controlled inoculation of microfilariae. We showed that the rapid clearance of microfilariae from the pleural cavity or from the bloodstream of CBA/Ca mice was associated with a massive accumulation of first stage larvae in the lungs, liver and spleen.

Published
2012
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19. Association of Institutes for Bee Research Report of the 55th Seminar in Hohen Neuendorf 11–13March 2008

Author

Scheiner, R., Alkattea, R., Steidle, H., Rosenkranz, P., Grünewald, B., Bartsch, C., Giurfa, M., Devaud, J. -M., Lein, J., Becher, M., Moritz, R. F. A., Fuchs, S., Riessberger-Gallé, U., Vollmann, J., Brodschneider, R., Aupinel, P., Crailsheim, K., Elmi, M. Pour, Haddad, N., de Miranda, J. R., Siede, R., König, M., Büchler, R., Thiel, H. -J., Gisder, S., Aumeier, P., Yue, C., Genersch, E., Šekulja, D., Garrido, C., Bienefeld, K., Ehrhardt, K., Ziegelmann, B., Steidle, J., Joachimsmeier, I., Kirchner, W. H., Ashiralieva, A., Fünfhaus, A., Borriss, R., Randolt, K., Gimple, O., Gätschenberger, H., Beier, H., Tautz, J., Loncaric, I., Derakhshifar, I., Köglberger, H., Moosbeckhofer, R., Oberlerchner, J., Riedel, M., Yue, D., Nordhoff, M., Wieler, L. H., Harz, M., Rademacher, E., Berg, S., Schürzinger, F., Illies, I., Radtke, J., Neuberger, P., Kovac, H., Bartzsch, C., Trompelt, J., Feller, K. -H., Schmidt, W., and Etzold, E.

Published
2008
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20. Two-pion production in proton-proton collisions with a polarized beam

Author

El-Bary, S. Abd, El-Samad, S. Abd, Bilger, R., Brinkmann, K. -Th., Clement, H., Dietrich, M., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Geyer, R., Gillitzer, A., Hanhart, C., Hauffe, J., Haug, K., Hesselbarth, D., Jaekel, R., Jakob, B., Karsch, L., Kilian, K., Koch, H., Kress, J., Kuhlmann, E., Marcello, S., Marwinski, S., Meier, R., Möller, K., Morsch, H. P., Naumann, L., Ritman, J., Roderburg, E., Schönmeier, P., Schulte-Wissermann, M., Schroeder, W., Steinke, M., Stinzing, F., Sun, G. Y., Wächter, J., Wagner, G. J., Wagner, M., Weidlich, U., Wilms, A., Wintz, P., Wirth, S., Zhang, G., Zupranski, P., and The COSY-TOF Collaboration

Published
2008
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26. Erratum to: Production of $ \Sigma^{0}_{}$ hyperons in proton-proton collisions

Author

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

Published
2010
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29. Determination of the spin triplet p Λ scattering length from the final state interaction in the p - p→pK+ Λ reaction

Author

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

Subjects
Physik (inkl. Astronomie)
Published
2017

30. Analyzing power Ay for ω meson production in proton–proton collisions

Author

Abdel-Bary, M., Brinkmann, K.-Th., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Freiesleben, H., Gillitzer, A., Gottwald, J., Jä, R., Karsch, L., Kilian, K., Kuhlmann, E., Morsch, H.P., Pizzolotto, C., Reimann, S., Ritman, J., Roderburg, E., Schroeder, W., Schulte-Wissermann, M., Sefzick, T., Sun, G.Y., Teufel, A., Ullrich, W., Wenzel, R., Wintz, P., Wüstner, P., and Zupranski, P.

Subjects
Nuclear and High Energy Physics
Published
2008
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31. First Model-Independent Measurement of the Spin Triplet $p��$ Scattering Length from Final State Interaction in the $\vec{p}p \rightarrow pK^{+}��$ Reaction

Author

TOF Collaboration, Hauenstein, F., Borodina, E., Clement, H., Doroshkevich, E., Dzhygadlo, R., Ehrhardt, K., Eyrich, W., Gast, W., Gillitzer, A., Grzonka, D., Haidenbauer, J., Hanhart, C., Jowzaee, S., Kilian, K., Klaja, P., Kober, L., Krapp, M., Mertens, M., Moskal, P., Ritman, J., Roderburg, E., R��der, M., Schroeder, W., Sefzick, T., Wintz, P., and W��stner, P.

Subjects
FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The $\vec{p}p \rightarrow pK^{+}��$ reaction has been measured with the COSY-TOF detector at a beam momentum of $2.7\,\mathrm{GeV}/c$. The polarized proton beam enables the measurement of the beam analyzing power by the asymmetry of the produced kaon ($A_N^{K}$). This observable allows the $p��$ spin triplet scattering length to be extracted for the first time model independently from the final-state interaction in the reaction. The obtained value is $a_{t} = (-2.55 ^{+0.72}_{-1.39} {}_{\textrm{stat.}} \pm 0.6_{\textrm{syst.}} \pm 0.3_{\textrm{theo.}})\mathrm{fm}$. This value is compatible with theoretical predictions and results from model-dependent analyses., Revised version as accepted for publication in PRC

Published
2016
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34. Antimalarial NADPH-Consuming Redox-Cyclers as Superior G6PD Deficiency Copycats

Author

Bielitza, M, Belorgey, D, Ehrhardt, K, Johann, L, Lanfranchi, Da, Gallo, Valentina, Keiling, BRIGITTE EVELIN, Mohring, F, Jortzik, E, Williams, Dl, Becker, K, Arese, Paolo, Elhabiri, M, and Davioud Charvet, E.

Subjects
malaria, redox cycler, Antimalarial drugs, G6PD glucose 6-phosphate dehydrogenase
Published
2015

35. «Self assembled lamellar metallo-dielectric nanocomposite with strong optical anisotropy»

Author

Tallet, C., Baron, A., Ehrhardt, K., Vieaud, J., Merchiers, O., Barois, P., Warenghem, M., Ponsinet, V., Raigi SA (Raigi), Centre d'Energétique et de Thermique de Lyon (CETHIL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Centre de recherches Paul Pascal (CRPP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), UCCS Équipe Couches Minces & Nanomatériaux, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille-Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
[PHYS]Physics [physics], [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

37. Efficient integral equation approach for periodic multilayered metamaterial structures

Author

Ozdemir, Nilufer Aslihan, Craeye, Christophe, Ehrhardt, K., Aradian, A., 7th European Conference on Antennas and Propagation - EUCAP 2013, and UCL - SST/ICTM/ELEN - Pôle en ingénierie électrique

Subjects
Metamaterials, Physics::Optics
Abstract

This study exploits the surface equivalence principle to obtain a reduced system of equations for a problem that includes doubly periodic infinite arrays of multi-layers of core-shell nanoparticles, illuminated by a plane wave, above a dielectric substrate. The proposed approach allows a different host medium for each layer of nanoparticles without employing multilayered media Green’s function.

Published
2013

38. Final-State Interactions in the Process pp -> pKLambda

Author

R��der, M., Borodina, E., Clement, H., Doroshkevich, E., Dzhygadlo, R., Ehrhardt, K., Erhardt, A., Eyrich, W., Gast, W., Gillitzer, A., Grzonka, D., Haidenbauer, J., Hanhart, C., Hauenstein, F., Klaja, P., Kober, L., Kilian, K., Krapp, M., Mertens, M., Ritman, J., Roderburg, E., Schroeder, W., Sefzick, T., Sibirtsev, A., Wintz, P., and W��stner, P.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

The possibility to determine the pLambda scattering length from the final-state interaction in the reaction pp->pKLambda is investigated experimentally. From a transversely polarized measurement, the K analyzing power (A_N) which, in principle, allows one to extract the spin triplet scattering length is studied. An unexpected energy dependence of the forward/backward symmetric part of A_N is found. The influence of N*-resonances on the pLambda invariant mass spectrum is investigated by exploiting the large acceptance for the process pp->pKLambda->pKppi and is found to be the main source of uncertainty for determining the pLambda scattering length.

Published
2013
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39. «Synthesis, optical characterization and modeling metallic nanoparticles in different host matrix ambient. Review of Nanodiellipso project»

Author

Aradian, A., Barois, P., Baron, A., Ehrhardt, K., Malassis, L., Merchiers, O., Ponsinet, V., Tallet, C., Vieaud, J., Zheng, Z., Borensztein, Y., Coursault, D., Gallas, B., Lacaze, E., Cattelan, D., Kouznetsov, D., Stchakovsky, M., Blach, J-F., Henninot, J-F., Nemer, S., Warenghem, M., Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), UCCS Équipe Couches Minces & Nanomatériaux, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille-Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
[PHYS]Physics [physics], [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2013

43. The Chemokine CXCL12 Is Essential for the Clearance of the Filaria Litomosoides sigmodontis in Resistant Mice

Author

Bouchery, T. (Tiffany), Dénécé, G. (Gaelle), Attout, T. (Tarik), Ehrhardt, K. (Katharina), Lhermitte-Vallarino, N. (Nathaly), Hachet-Haas, M. (Muriel), Galzi, J. (Jean-luc), Brotin, E. (Emilie), Bachelerie, F. (Françoise), Gavotte, L. (Laurent), Moulia, C. (Catherine), Bain, O. (Odile), Martin, C. (Coralie), Rénia, L. (Laurent) (editor), Molécules de Communication et Adaptation des Micro-organismes (MCAM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut Gilbert-Laustriat : Biomolécules, Biotechnologie, Innovation Thérapeutique, Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Biotechnologie et signalisation cellulaire (BSC), Université de Strasbourg (UNISTRA)-Institut de recherche de l'Ecole de biotechnologie de Strasbourg (IREBS)-Centre National de la Recherche Scientifique (CNRS), Centre Régional de Lutte contre le Cancer François Baclesse [Caen] (UNICANCER/CRLC), Normandie Université (NU)-UNICANCER-Tumorothèque de Caen Basse-Normandie (TCBN), Cytokines, chimiokines et immunopathologie, Université Paris-Sud - Paris 11 (UP11)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), martin, coralie, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche de l'Ecole de biotechnologie de Strasbourg (IREBS), UNICANCER-Tumorothèque de Caen Basse-Normandie (TCBN)-Normandie Université (NU), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226, Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Réponse immunitaire et developpement chez les insectes (RIDI - UPR 9002), Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Molécules de Communication et Adaptation des Micro-Organismes (MCAM), Centre Régional de Lutte contre le Cancer François Baclesse (CRLC François Baclesse ), Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Institut Cochin (UMR_S567 / UMR 8104), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5), Centre National de la Recherche Scientifique (CNRS), and Sorbonne Universités

Subjects
Chemokine, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, Mouse, medicine.medical_treatment, Cell, lcsh:Medicine, CXCR4, Mice, 0302 clinical medicine, Morphogenesis, Parasite hosting, lcsh:Science, Immune Response, ComputingMilieux_MISCELLANEOUS, 0303 health sciences, Mice, Inbred BALB C, Multidisciplinary, Sciences du Vivant [q-bio]/Biotechnologies, Animal Models, Filariasis, Host-Pathogen Interaction, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, medicine.anatomical_structure, Lymphatic system, Infectious Diseases, Cytokines, Medicine, Research Article, Immunology, Biology, Microbiology, 03 medical and health sciences, Immune system, Model Organisms, medicine, Parasitic Diseases, Animals, Immunity to Infections, Filarioidea, 030304 developmental biology, Growth Control, Growth factor, lcsh:R, Immunity, Pleural cavity, Chemokine CXCL12, [SDV.BIO] Life Sciences [q-bio]/Biotechnology, Mice, Inbred C57BL, Immune System, biology.protein, lcsh:Q, Parasitology, 030215 immunology, Developmental Biology
Abstract

Litomosoides sigmodontis is a cause of filarial infection in rodents. Once infective larvae overcome the skin barrier, they enter the lymphatic system and then settle in the pleural cavity, causing soft tissue infection. The outcome of infection depends on the parasite's modulatory ability and also on the immune response of the infected host, which is influenced by its genetic background. The goal of this study was to determine whether host factors such as the chemokine axis CXCL12/CXCR4, which notably participates in the control of immune surveillance, can influence the outcome of the infection. We therefore set up comparative analyses of subcutaneous infection by L. sigmodontis in two inbred mouse strains with different outcomes: one susceptible strain (BALB/c) and one resistant strain (C57BL/6). We showed that rapid parasite clearance was associated with a L. sigmodontis-specific CXCL12-dependent cell response in C57BL/6 mice. CXCL12 was produced mainly by pleural mesothelial cells during infection. Conversely, the delayed parasite clearance in BALB/c mice was neither associated with an increase in CXCL12 levels nor with cell influx into the pleural cavity. Remarkably, interfering with the CXCL12/CXCR4 axis in both strains of mice delayed filarial development, as evidenced by the postponement of the fourth molting process. Furthermore, the in vitro growth of stage 4 filariae was favored by the addition of low amounts of CXCL12. The CXCL12/CXCR4 axis thus appears to have a dual effect on the L. sigmodontis life cycle: by acting as a host-cell restriction factor for infection, and as a growth factor for worms.

Published
2012
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44. The pK0��+ final state in proton-proton collisions

Author

TOF Collaboration, Abdel-Bary, M., Abdel-Samad, S., Brinkmann, K-Th., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Gast, W., Georgi, J., Gillitzer, A., Gottwald, J., Hesselbarth, D., J��ger, H., Jakob, B., J��kel, R., Karsch, L., Kilian, K., Koch, H., Krapp, M., Kre��, J., Kuhlmann, E., Lehmann, A., Marcello, S., Marwinski, S., Mauro, S., Meyer, W., Michel, P., M��ller, K., Morsch, H. P., M��rtel, H., Naumann, L., Paul, N., Pinna, L., Pizzolotto, C., Plettner, Ch., Reimann, S., Richter, M., Ritman, J., Roderburg, E., Schamlott, A., Sch��nmeier, P., Schroeder, W., Schulte-Wissermann, M., Sefzick, T., Stinzing, F., Steinke, M., Sun, G. Y., Teufel, A., Ullrich, W., Wagner, G. J., Wagner, M., Wenzel, R., Wilms, A., Wintz, P., Wirthand, S., W��stner, P., and Zupranski, P.

Subjects
Nuclear Theory (nucl-th), FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

This paper reports results from a study of the reaction pp->pK0��+ at beam momenta of p_{beam} = 2950, 3059, and 3200 MeV/c (excess energies of ��= 126, 161, and 206 MeV). Total cross sections were determined for all energies; a set of differential cross sections (Dalitz plots; invariant mass spectra of all two-body subsystems; angular distributions of all final state particles; distributions in helicity and Jackson frames) are presented for ��= 161 MeV. The total cross sections are proportional to the volume of available three-body phase-space indicating that the transition matrix element does not change significantly in this range of excess energies. It is concluded from the differential data that the reaction proceeds dominantly via the N(1710)P_{11} and/or N(1720)P_{13} resonance(s); N(1650)S_{11} and ��(1600)P_{33} could also contribute., 15 pages, 10 figures

Published
2012
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45. The pK0Σ+ final state in proton-proton collisions

Author

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

Abstract

This paper reports results from a study of the reaction pp->pK0\Sigma+ at beam momenta of p_{beam} = 2950, 3059, and 3200 MeV/c (excess energies of \epsilon= 126, 161, and 206 MeV). Total cross sections were determined for all energies; a set of differential cross sections (Dalitz plots; invariant mass spectra of all two-body subsystems; angular distributions of all final state particles; distributions in helicity and Jackson frames) are presented for \epsilon= 161 MeV. The total cross sections are proportional to the volume of available three-body phase-space indicating that the transition matrix element does not change significantly in this range of excess energies. It is concluded from the differential data that the reaction proceeds dominantly via the N(1710)P_{11} and/or N(1720)P_{13} resonance(s); N(1650)S_{11} and \Delta(1600)P_{33} could also contribute.

Published
2012

46. Systematic study of the pp -> pp omega reaction

Author

Abdel-Bary, M., Abdel-Samad, S., Brinkmann, K., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Gast, W., Gillitzer, A., Gottwald, J., Jager, H., Jakob, B., Jakel, R., Karsch, L., Kilian, K., Koch, H., Krapp, M., Kress, J., Kuhlmann, E., Lehmann, A., Marcello, S., Mauro, S., Michel, P., Moller, K., Morsch, H., Naumann, L., Paul, N., Pizzolotto, C., Plettner, C., Reimann, S., Richter, M., Ritman, J., Roderburg, E., Schamlott, A., Schonmeier, P., Schroeder, W., Schulte-Wissermann, M., Sefzick, T., Steinke, M., Sun, G., Teufel, A., Ullrich, W., Wagner, G., Wagner, M., Wenzel, R., Wilms, A., Wintz, P., Wustner, P., and Zupranski, P.

Subjects
+400+MeV%29%22">Other reactions above meson production thresholds (energies > 400 MeV), Nuclear reactions involving few-nucleon systems, nucleon-nucleon interactions, Nucleon-nucleon interactions, Other mesons with S=C=0, mass < 2.5 GeV, vector meson production, polarization in interactions and scattering, Nuclear Experiment, Polarization in interactions and scattering
Abstract

A systematic study of the production of omega-mesons in proton-proton-collisions was carried out in a kinematically complete experiment at three excess energies (epsilon= 92, 128, 173 MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum J¨ulich. The total cross section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant mass spectra were determined. We observe !-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and, additionally, in Sd at epsilon = 173 MeV. No obvious indication of resonant omega-production via N*- resonances was found, as proton angular distributions are almost isotropic and invariant mass spectra are compatible with phase space distributions. A dominant role of 3P1 and 1S0 initial partial waves for omega-production was concluded from the orientation of the decay plane of the !-meson. Although the Jackson angle distributions in the omega-p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega-p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process.

Published
2010

47. Systematic study of the pp -> pp omega reaction

Author

TOF Collaboration, Abdel-Bary, M., Abdel-Samad, S., Brinkmann, K. -Th., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Gast, W., Gillitzer, A., Gottwald, J., J��ger, H., Jakob, B., J��kel, R., Karsch, L., Kilian, K., Koch, H., Krapp, M., Kre��, J., Kuhlmann, E., Lehmann, A., Marcello, S., Mauro, S., Michel, P., M��ller, K., Morsch, H. P., Naumann, L., Paul, N., Pizzolotto, C., Plettner, Ch., Reimann, S., Richter, M., Ritman, J., Roderburg, E., Schamlott, A., Sch��nmeier, P., Schroeder, W., Schulte-Wissermann, M., Sefzick, T., Steinke, M., Sun, G. Y., Teufel, A., Ullrich, W., Wagner, G. J., Wagner, M., Wenzel, R., Wilms, A., Wintz, P., W��stner, P., and Zupranski, P.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

A systematic study of the production of omega-mesons in proton-proton-collisions was carried out in a kinematically complete experiment at three excess energies(epsilon= 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum J��lich. The total cross section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and, additionally, in Sd at epsilon= 173 MeV. No obvious indication of resonant omega-production via N^*-resonances was found, as proton angular distributions are almost isotropic and invariant mass spectra are compatible with phase space distributions. A dominant role of ^3P_1 and ^1S_0 initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega-p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega-p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process., 17 pages, 16 figures, accepted for publication in EPJA

Published
2010
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48. Influence of N*-resonances on hyperon production in the channel pp->K+ Lambda p at 2.95, 3.20 and 3.30 GeV/c beam momentum

Author

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

Subjects
Associated strangeness production, hyperon production, total cross-section, baryon resonances, Dalitz plot
Published
2010

49. Influence of N*-resonances on hyperon production in the channel pp->K+ Lambda p at 2.95, 3.20 and 3.30 GeV/c beam momentum

Author

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

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

Hyperon production in the threshold region was studied in the reaction pp -> K+Lp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at the three different beam momenta of p_beam=2.95, 3.20 and 3.30 GeV/c, corresponding to excess energies of epsilon=204, 285 and 316 MeV, respectively. Total cross-sections were deduced for the three beam momenta to be 23.9+/-0.8 +/-2.0 ub, 28.4+/-1.3 +/-2.2 ub and 35.0+/-1.3 +/-3.0 ub. Differential observables including Dalitz plots were obtained. The analysis of the Dalitz plots reveals a strong influence of the N(1650)-resonance at p_beam=2.95 GeV/c, whereas for the higher momenta an increasing relative contribution of the N(1710)- and/or of the N(1720)-resonance was observed. In addition, the pL-final-state interaction turned out to have a significant influence on the Dalitz plot distribution., accepted for publication at Physics Letters B; some minor text changes were done; also the scale of the ordinates of figure 9 has been changed

Published
2010
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50. Comparison of isoscalar vector meson production cross sections in proton-proton collisions

Author

Abdel-Bary, A., Abdel-Samad, S., Brinkmann, K.-T., Clement, H., Dietrich, J., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, A., Gillitzer, A., Hesselbarth, D., Jaekel, R., Karsch, L., Kilian, K., Kuhlmann, E., Marcello, S., Michel, P., Moeller, K., Morsch, H. P., Pizzolotto, C., Plettner, C., Ritman, J., Roderburg, E., Schoenmeier, P., Schroeder, W., Schulte-Wissermann, M., Steinke, M., Sun, G. J., Ullrich, W., Wenzel, R., Wintz, P., Wagner, M., Wilms, A., Wirth, S., and Zupranski, P.

Subjects
Cross sections, pp→ppω, Vector meson production, Angular distributions, Strangeness of the nucleon, OZI-violation
Abstract

The reaction pp→ppω was investigated with the TOF spectrometer, which is an external experiment at the accelerator COSY (Forschungszentrum Jülich, Germany). Total as well as differential cross sections were determined at an excess energy of 93 MeV (pbeam=2950 MeV/c). Using the total cross section of (9.0±0.7±1.1) μb for the reaction pp→ppω determined here and existing data for the reaction pp→ppphi, the ratio Click to view the MathML source turns out to be significantly larger than expected by the Okubo–Zweig–Iizuka (OZI) rule. The uncertainty of this ratio is considerably smaller than in previous determinations. The differential distributions show that the ω production is still dominated by S-wave production at this excess energy, however higher partial waves clearly contribute. A comparison of the measured angular distributions for ω production to published distributions for phi production at 83 MeV shows that the data are consistent with an identical production mechanism for both vector mesons.

Published
2007

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