Author: "Wendel Ch" / Database: OpenAIRE - Searchworks@Jio Institute Digital Library Search Results

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41 results on '"Wendel Ch"'

1. Polarization observables in double neutral pion photoproduction

Author: TAPS Collaboration, Seifen, T., Hartmann, J., Afzal, F., Anisovich, A. V., Beck, R., Becker, M., Berlin, A., Bichow, M., Brinkmann, K. -Th., Crede, V., Dieterle, M., Dutz, H., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Grüner, M., Görtz, St., Gutz, E., Hammann, Ch., Hannappel, J., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Lang, M., Mahlberg, Ph., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Müllers, J., Nanova, M., Nikonov, K., Nikonov, V. A., Novotny, R., Reeve, S., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A. V., Schmidt, Ch., Schmieden, H., Schmitz, R., Schultes, J., Sokhoyan, V., Stausberg, N., Thiel, A., Thoma, U., Urban, M., Urff, G., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Witthauer, L., and Wunderlich, Y.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Measurements of target asymmetries and double-polarization observables for the reaction $\gamma p\to p\pi^0\pi^0$ are reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility (Bonn University) using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided transversely polarized protons. Linearly polarized photons were produced via bremsstrahlung off a diamond crystal. The data cover the photon energy range from $E_{\gamma}$=650 MeV to $E_{\gamma}$=2600 MeV and nearly the complete angular range. The results have been included in the BnGa partial wave analysis. Experimental results and the fit agree very well. Observed systematic differences in the branching ratios for decays of $N^*$ and $\Delta^*$ resonances are attributed to the internal structure of these excited nucleon states. Resonances which can be assigned to SU(6)$\times$O(3) two-oscillator configurations show larger branching ratios to intermediate states with non-zero intrinsic orbital angular momenta than resonances assigned to one-oscillator configurations., Comment: 21 pages, 27 figures
Published: 2022

2. Observation of a structure in the M$_{p\eta}$ invariant mass distribution near 1700 MeV/$c^2$ in the $\mathbf{\gamma p \rightarrow p \pi^0 \eta} $ reaction

Author: Metag, V., Nanova, M., Hartmann, J., Mahlberg, P., Afzal, F., Bartels, C., Bayadilov, D., Beck, R., Becker, M., Blanke, E., Brinkmann, K. -T., Ciupka, S., Crede, V., Dieterle, M., Dutz, H., Elsner, D., Frommberger, F., Gridnev, A., Gottschall, M., Grüner, M., Hammann, Ch., Hannappel, J., Hillert, W., Hoff, J., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kalinowsky, H., Kalischewski, F., Keshelashvili, I., Ketzer, B., Klassen, P., Klein, F., Koop, K., Kroenert, P., Krusche, B., Lang, M., Lopatin, I., Messi, F., Meyer, W., Mitlasóczky, B., Müller, J., Müllers, J., Nikonov, V., Novinsky, V., Novotny, R., Piontek, D., Reicherz, G., Richter, L., Rostomyan, T., Runkel, S., Salisbury, B., Sarantsev, A., Schaab, D., Schmidt, Ch., Schmieden, H., Schultes, J., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Stausberg, N., Thiel, A., Thoma, U., Triffterer, T., Urban, M., Urff, G., van Pee, H., Wagner, M., Walther, D., Wendel, Ch., Werthmüller, D., Wiedner, U., Wilson, A., Winnebeck, A., Witthauer, L., and Wunderlich, Y.
Subjects: Nuclear Theory, Nuclear Experiment
Abstract: The reaction $\gamma p \rightarrow p \pi^0 \eta$ has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has been motivated by the recently claimed observation of a narrow structure in the M$_{N\eta}$ invariant mass distribution at a mass of 1678 MeV/$c^2$. The existence of this structure cannot be confirmed in the present work. Instead, for E$_{\gamma}$ = 1400 - 1500 MeV and the cut M$_{p\pi^0} \le 1190 $ MeV/$c^2$ a statistically significant structure in the M$_{p\eta}$ invariant mass distribution near 1700 MeV/$c^2$ is observed with a width of $\Gamma\approx 35$ MeV/$c^2$ while the mass resolution is $\sigma_{res}$ = 5 MeV/$c^2$. Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from $\approx$ 1700MeV/c$^2$ to $\approx$ 1725 MeV/$c^2$; the width increases to about 50 MeV/$c^2$ and decreases thereafter. The cross section associated with this structure reaches a maximum of $\approx$ 100 nb around E$_{\gamma} \approx$ 1490 MeV (W $\approx $ 1920 MeV), which coincides with the $p a_0$ threshold. Three scenarios are discussed which might be the origin of this structure in the M$_{p\eta}$ invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the $\gamma p \rightarrow p a_0 \rightarrow p \pi^0 \eta$ reaction, Comment: 16 pages, 18 figure
Published: 2021

3. Observation of a structure in the M$_{p��}$ invariant mass distribution near 1700 MeV/$c^2$ in the $\mathbf{��p \rightarrow p ��^0 ��} $ reaction

Author: Metag, V., Nanova, M., Hartmann, J., Mahlberg, P., Afzal, F., Bartels, C., Bayadilov, D., Beck, R., Becker, M., Blanke, E., Brinkmann, K. -T., Ciupka, S., Crede, V., Dieterle, M., Dutz, H., Elsner, D., Frommberger, F., Gridnev, A., Gottschall, M., Gr��ner, M., Hammann, Ch., Hannappel, J., Hillert, W., Hoff, J., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kalinowsky, H., Kalischewski, F., Keshelashvili, I., Ketzer, B., Klassen, P., Klein, F., Koop, K., Kroenert, P., Krusche, B., Lang, M., Lopatin, I., Messi, F., Meyer, W., Mitlas��czky, B., M��ller, J., M��llers, J., Nikonov, V., Novinsky, V., Novotny, R., Piontek, D., Reicherz, G., Richter, L., Rostomyan, T., Runkel, S., Salisbury, B., Sarantsev, A., Schaab, D., Schmidt, Ch., Schmieden, H., Schultes, J., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Stausberg, N., Thiel, A., Thoma, U., Triffterer, T., Urban, M., Urff, G., van Pee, H., Wagner, M., Walther, D., Wendel, Ch., Werthm��ller, D., Wiedner, U., Wilson, A., Winnebeck, A., Witthauer, L., and Wunderlich, Y.
Subjects: Nuclear Theory (nucl-th), Nuclear Theory, Physics::Accelerator Physics, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The reaction $��p \rightarrow p ��^0 ��$ has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has been motivated by the recently claimed observation of a narrow structure in the M$_{N��}$ invariant mass distribution at a mass of 1678 MeV/$c^2$. The existence of this structure cannot be confirmed in the present work. Instead, for E$_��$ = 1400 - 1500 MeV and the cut M$_{p��^0} \le 1190 $ MeV/$c^2$ a statistically significant structure in the M$_{p��}$ invariant mass distribution near 1700 MeV/$c^2$ is observed with a width of $��\approx 35$ MeV/$c^2$ while the mass resolution is $��_{res}$ = 5 MeV/$c^2$. Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from $\approx$ 1700MeV/c$^2$ to $\approx$ 1725 MeV/$c^2$; the width increases to about 50 MeV/$c^2$ and decreases thereafter. The cross section associated with this structure reaches a maximum of $\approx$ 100 nb around E$_�� \approx$ 1490 MeV (W $\approx $ 1920 MeV), which coincides with the $p a_0$ threshold. Three scenarios are discussed which might be the origin of this structure in the M$_{p��}$ invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the $��p \rightarrow p a_0 \rightarrow p ��^0 ��$ reaction, 16 pages, 18 figure
Published: 2021
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4. Measurement of the Helicity Asymmetry $E$ for the reaction $ \gamma p\to \pi^0 p$

Author: collaboration, CBELSA/TAPS, Gottschall, M., Afzal, F., Anisovich, A. V., Bayadilov, D., Beck, R., Bichow, M., Brinkmann, K. -Th., Crede, V., Dieterle, M., Dietz, F., Dutz, H., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Gridnev, A., Grüner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kammer, S., Kalinowsky, H., Keshelashvili, I., Klassen, P., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Mahlberg, P., Makonyi, K., Metag, V., Meyer, W., Müller, J., Müllers, J., Nanova, M., Nikonov, V., Novotny, R., Piontek, D., Reicherz, G., Rostomyan, T., Sarantsev, A., Schmidt, Ch., Schmieden, H., Seifen, T., Sokhoyan, V., Spieker, K., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Werthmüller, D., Wiedner, U., Wilson, A., Winnebeck, A., Witthauer, L., and Wunderlich, Y.
Subjects: Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment
Abstract: A measurement of the double-polarization observable $E$ for the reaction $\gamma p\to \pi^0 p$ is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from $E_\gamma =600$~MeV to $E_\gamma =2310$~MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses., Comment: 21 pages
Published: 2019

5. Measurement of the Helicity Asymmetry $E$ for the reaction $ ��p\to ��^0 p$

Author: TAPS Collaboration, Gottschall, M., Afzal, F., Anisovich, A. V., Bayadilov, D., Beck, R., Bichow, M., Brinkmann, K. -Th., Crede, V., Dieterle, M., Dietz, F., Dutz, H., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Gridnev, A., Gr��ner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kammer, S., Kalinowsky, H., Keshelashvili, I., Klassen, P., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Mahlberg, P., Makonyi, K., Metag, V., Meyer, W., M��ller, J., M��llers, J., Nanova, M., Nikonov, V., Novotny, R., Piontek, D., Reicherz, G., Rostomyan, T., Sarantsev, A., Schmidt, Ch., Schmieden, H., Seifen, T., Sokhoyan, V., Spieker, K., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Werthm��ller, D., Wiedner, U., Wilson, A., Winnebeck, A., Witthauer, L., and Wunderlich, Y.
Subjects: Nuclear Theory, Physics::Accelerator Physics, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: A measurement of the double-polarization observable $E$ for the reaction $��p\to ��^0 p$ is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from $E_��=600$~MeV to $E_��=2310$~MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses., 21 pages
Published: 2019
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6. The {\eta}'-carbon potential at low meson momenta

Author: Nanova, M., Friedrich, S., Metag, V., Paryev, E. Ya., Afzal, F. N., Bayadilov, D., Bantes, B., Beck, R., Becker, M., Böse, S., Brinkmann, K. -T., Crede, V., Drexler, P., Eberhardt, H., Elsner, D., Frommberger, F., Funke, Ch., Gottschall, M., Grüner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kaiser, D., Kalischewski, F., Keshelashvili, I., Klein, F., Koop, K., Krusche, B., Lang, M., Makonyi, K., Messi, F., Müller, J., Müllers, J., Piontek, D., Rostomyan, T., Schaab, D., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Thiel, A., Thoma, U., Triffterer, T., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Werthmüller, D., Wiedner, U., Wilson, A., Witthauer, L., Wunderlich, Y., and Zaunick, H. -G.
Subjects: High Energy Physics::Experiment, Nuclear Experiment
Abstract: The production of $\eta^\prime$ mesons in coincidence with forward-going protons has been studied in photon-induced reactions on $^{12}$C and on a liquid hydrogen (LH$_2$) target for incoming photon energies of 1.3-2.6 GeV at the electron accelerator ELSA. The $\eta^\prime$ mesons have been identified via the $\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6 \gamma$ decay registered with the CBELSA/TAPS detector system. Coincident protons have been identified in the MiniTAPS BaF$_2$ array at polar angles of $2^{\circ} \le \theta _{p} \le 11^{\circ}$. Under these kinematic constraints the $\eta^\prime$ mesons are produced with relatively low kinetic energy ($\approx$ 150 MeV) since the coincident protons take over most of the momentum of the incident-photon beam. For the C-target this allows the determination of the real part of the $\eta^\prime$-carbon potential at low meson momenta by comparing with collision model calculations of the $\eta^\prime$ kinetic energy distribution and excitation function. Fitting the latter data for $\eta^\prime$ mesons going backwards in the center-of-mass system yields a potential depth of V = $-$(44 $\pm$ 16(stat)$\pm$15(syst)) MeV, consistent with earlier determinations of the potential depth in inclusive measurements for average $\eta^\prime$ momenta of $\approx$ 1.1 GeV/$c$. Within the experimental uncertainties, there is no indication of a momentum dependence of the $\eta^\prime$-carbon potential. The LH$_2$ data, taken as a reference to check the data analysis and the model calculations, provide differential and integral cross sections in good agreement with previous results for $\eta^\prime$ photoproduction off the free proton., Comment: 9 pages, 13 figures. arXiv admin note: text overlap with arXiv:1608.06074
Published: 2018

7. The $\eta^{\prime}$η-carbon potential at low meson momenta

Author: Nanova, M., Friedrich, S., Brinkmann, K. -T., Crede, V., Drexler, P., Eberhardt, H., Elsner, D., Frommberger, F., Funke, Ch., Gottschall, M., Grüner, M., Gutz, E., Metag, V., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kaiser, D., Kalischewski, F., Keshelashvili, I., Paryev, E. Ya., Klein, F., Koop, K., Krusche, B., Lang, M., Makonyi, K., Messi, F., Müller, J., Müllers, J., Piontek, D., Rostomyan, T., Afzal, F. N., Schaab, D., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Thiel, A., Thoma, U., Bayadilov, D., Triffterer, T., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Werthmüller, D., Wiedner, U., Wilson, A., Witthauer, L., Wunderlich, Y., Bantes, B., Zaunick, H. -G., Beck, R., Becker, M., and Böse, S.
Subjects: Nuclear Theory, High Energy Physics::Experiment, ddc:530, Nuclear Experiment
Abstract: The production of η′ mesons in coincidence with forward-going protons has been studied in photon-induced reactions on 12C and on a liquid hydrogen (LH2) target for incoming photon energies of 1.3-2.6 GeV at the electron accelerator ELSA. The η′ mesons have been identified via the η′→π0π0η→6γ decay registered with the CBELSA/TAPS detector system. Coincident protons have been identified in the MiniTAPS BaF2 array at polar angles of 2∘≤θp≤11∘. Under these kinematic constraints the η′ mesons are produced with relatively low kinetic energy (≈150 MeV) since the coincident protons take over most of the momentum of the incident-photon beam. For the C-target this allows the determination of the real part of the η′-carbon potential at low meson momenta by comparing with collision model calculations of the η′ kinetic energy distribution and excitation function. Fitting the latter data for η′ mesons going backwards in the center-of-mass system yields a potential depth of V=−(44±16(stat)±15(syst)) MeV, consistent with earlier determinations of the potential depth in inclusive measurements for average η′ momenta of ≈1.1 GeV/c. Within the experimental uncertainties, there is no indication of a momentum dependence of the η′-carbon potential. The LH2 data, taken as a reference to check the data analysis and the model calculations, provide differential and integral cross sections in good agreement with previous results for η′ photoproduction off the free proton.
Published: 2018

8. The polarization observables T, P, and H and their impact on γp→pπ0 multipoles

Author: Hartmann, J., Dutz, H., Anisovich, A.V., Bayadilov, D., Beck, R., Becker, M., Beloglazov, Y., Berlin, A., Bichow, M., Böse, S., Brinkmann, K.-Th., Crede, V., Dieterle, M., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Grüner, M., Goertz, St., Gutz, E., Hammann, Ch., Hannappel, J., Hannen, V., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Nanova, M., Nikonov, V., Novinski, D., Novotny, R., Piontek, D., Reeve, S., Rosenbaum, Ch., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thämer, Ph., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Witthauer, L.
Subjects: Nuclear and High Energy Physics
Published: 2015
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9. Data on Is and Ic in γ→p→pπ0π0 reveal cascade decays of N(1900) via N(1520)π

Author: Sokhoyan, V., Gutz, E., van Pee, H., Anisovich, A.V., Bacelar, J.C.S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y., Castelijns, R., Crede, V., Dutz, H., Elsner, D., Ewald, R., Frommberger, F., Fuchs, M., Funke, Ch., Gregor, R., Gridnev, A., Hillert, W., Hoffmeister, Ph., Horn, I., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Kotulla, M., Krusche, B., Lang, M., Löhner, H., Lopatin, I., Lugert, S., Mertens, T., Messchendorp, J.G., Metag, V., Nanova, M., Nikonov, V.A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., Pfeiffer, M., Piontek, D., Roy, A., Sarantsev, A.V., Schmidt, Ch., Schmieden, H., Shende, S., Süle, A., Sumachev, V.V., Szczepanek, T., Thiel, A., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., and Wilson, A.
Subjects: Nuclear and High Energy Physics
Published: 2015
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10. Measurement of polarisation observables in Ks0Σ+ photoproduction off the proton

Author: Ewald, R., Anisovich, A.V., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y.A., Brinkmann, K.-T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A.B., Gutz, E., Hannappel, J., Hillert, W., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T.C., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I.V., Menze, D., Mertens, T., Messchendorp, J.G., Metag, V., Nanova, M., Nikonov, V.A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Sarantsev, A.V., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Süle, A., Sumachev, V.V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Polarisation in interactions and scattering, Nuclear Theory, Meson production, High Energy Physics::Experiment, Decays of baryons, Other strange mesons, Nuclear Experiment, lcsh:Physics, lcsh:QC1-999, Baryon resonances (SCB0)
Abstract: The reaction γp→KS0Σ+ is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to Eγ=1650MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay Σ+→pπ0 up to Eγ=2250MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed prominent structure in the cross section near the K⁎ thresholds is discussed. Keywords: Meson production, Other strange mesons, Baryon resonances (SCB0), Decays of baryons, Polarisation in interactions and scattering
Published: 2014

11. Measurement of polarisation observables in Ks0Σ+ photoproduction off the proton

Author: Ewald, R., Anisovich, A.V., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y.A., Brinkmann, K.-T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A.B., Gutz, E., Hannappel, J., Hillert, W., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T.C., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I.V., Menze, D., Mertens, T., Messchendorp, J.G., Metag, V., Nanova, M., Nikonov, V.A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Sarantsev, A.V., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Süle, A., Sumachev, V.V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Nuclear and High Energy Physics
Published: 2014
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12. Momentum dependence of the imaginary part of the ω - and η -nucleus optical potential

Author: Friedrich, S., Nanova, M., Metag, V., Afzal, F. N., Bayadilov, D., Bantes, B., Beck, R., Becker, M., Böse, S., Brinkmann, K. T., Crede, V., Drexler, P., Eberhardt, H., Elsner, D., Frommberger, F., Funke, Ch, Gottschall, M., Grüner, M., Gutz, E., Hammann, Ch, Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph, Honisch, Ch, Jude, T., Kaiser, D., Kalischewski, F., Keshelashvili, I., Klein, F., Koop, K., Krusche, B., Makonyi, K., Messi, F., Müller, J., Müllers, J., Piontek, D. M., Rostomyan, T., Schaab, D., Schmidt, Ch, Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Thiel, A., Thoma, U., Triffterer, T., Urban, M., van Pee, H., Walther, D., Wendel, Ch, Werthmüller, D., Wiedner, U., Witthauer, L., Wunderlich, Y., and Zaunick, H. G.
Subjects: Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The photoproduction of ω and η mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9GeV at the electron accelerator ELSA. The mesons have been identified via the ω → π0 γ → 3 γ and η → π0η → 6 γ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium ω and η widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium ω width and η-N absorption cross sections. The energy dependence of the imaginary part of the ω- and η-nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the η-nucleus potential is found to be about three times smaller than recently determined values of the real part of the η-nucleus potential, which makes the η meson a suitable candidate for the search for meson-nucleus bound states. For the ω meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected, which makes the observation of ω mesic states very difficult experimentally.
Published: 2016

13. Momentum dependence of the imaginary part of the $��$- and $��^\prime$-nucleus optical potential

Author: Friedrich, S., Nanova, M., Metag, V., Afzal, F. N., Bayadilov, D., Bantes, B., Beck, R., Becker, M., B��se, S., Brinkmann, K. -T., Crede, V., Drexler, P., Eberhardt, H., Elsner, D., Frommberger, F., Funke, Ch., Gottschall, M., Gr��ner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jude, T., Kaiser, D., Kalischewski, F., Keshelashvili, I., Klein, F., Koop, K., Krusche, B., Lang, M., Makonyi, K., Messi, F., M��ller, J., M��llers, J., Piontek, D. -M., Rostomyan, T., Schaab, D., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Thiel, A., Thoma, U., Triffterer, T., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Werthm��ller, D., Wiedner, U., Wilson, A., Witthauer, L., Wunderlich, Y., and Zaunick, H. -G.
Subjects: High Energy Physics::Phenomenology, Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The photoproduction of $��$ and $��^\prime$ mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The mesons have been identified via the $��\rightarrow ��^0 ��\rightarrow 3 ��$ and $��^\prime\rightarrow ��^0 ��^0��\rightarrow 6 ��$ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium $��$ and $��^\prime$ widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium $��$ width and $��^\prime$-N absorption cross sections. The energy dependence of the imaginary part of the $��$- and $��^\prime$-nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the $��^\prime$ nucleus potential is found to be about three times smaller than recently determined values of the real part of the $��^\prime$-nucleus potential, which makes the $��^\prime$ meson a suitable candidate for the search for meson-nucleus bound states. For the $��$ meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected which makes the observation of $��$ mesic states very difficult experimentally., 10 pages, 8 figures
Published: 2016
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14. The polarization observables T , P , and H and their impact on γp→pπ0 multipoles

Author: Hartmann, J., Dutz, H., Anisovich, A.V., Bayadilov, D., Beck, R., Becker, M., Beloglazov, Y., Berlin, A., Bichow, M., Böse, S., Brinkmann, K.-Th., Crede, V., Dieterle, M., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Grüner, M., Goertz, St., Gutz, E., Hammann, Ch., Hannappel, J., Hannen, V., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Nanova, M., Nikonov, V., Novinski, D., Novotny, R., Piontek, D., Reeve, S., Rosenbaum, Ch., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thämer, Ph., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Witthauer, L.
Subjects: Polarization observables, Baryon spectroscopy, Nuclear Theory, Nuclear Experiment, Multipoles, Meson photoproduction, lcsh:Physics, lcsh:QC1-999
Abstract: Data on the polarization observables T , P , and H for the reaction γp→pπ0 are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. The data were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS detector. Within the Bonn-Gatchina partial wave analysis, the new polarization data lead to a significant narrowing of the error band for the multipoles for neutral-pion photoproduction.
Published: 2015

15. High statistics study of the reaction $\gamma p\to p\;2\pi^0$

Author: Sokhoyan, V., Gutz, E., Crede, V., van Pee, H., Anisovich, A. V., Bacelar, J. C. S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Castelijns, R., Dutz, H., Elsner, D., Ewald, R., Frommberger, F., Fuchs, M., Funke, Ch., Gregor, R., Gridnev, A. B., Hillert, W., Hoffmeister, Ph., Horn, I., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Kotulla, M., Krusche, B., Lang, M., Löhner, H., Lopatin, I. V., Lugert, S., Mertens, T., Messchendorp, J. G., Metag, V., Metsch, B., Nanova, M., Nikonov, V. A., Novinsky, D., Novotny, R., Ostrick, M., Pant, L., Pfeiffer, M., Piontek, D., Roy, A., Sarantsev, A. V., Schmidt, Ch., Schmieden, H., Seifen, T., Shende, S., Süle, A., Sumachev, V. V., Szczepanek, T., Thiel, A., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., and Wilson, A.
Subjects: Nuclear Experiment
Abstract: The photoproduction of 2$\pi^0$ mesons off protons was studied with the Crystal Barrel/TAPS experiment at the electron accelerator ELSA in Bonn. The energy of photons produced in a radiator was tagged in the energy range from 600\,MeV to 2.5\,GeV. Differential and total cross sections and $p\pi^0\pi^0$ Dalitz plots are presented. Part of the data was taken with a diamond radiator producing linearly polarized photons, and beam asymmetries were derived. Properties of nucleon and $\Delta$ resonances contributing to the $p\pi^0\pi^0$ final state were determined within the BnGa partial wave analysis. The data presented here allow us to determine branching ratios of nucleon and $\Delta$ resonances for their decays into $p\pi^0\pi^0$ via several intermediate states. Most prominent are decays proceeding via $\Delta(1232)\pi$, $N(1440)1/2^+\pi$, $N(1520)3/2^-\pi$, $N(1680)5/2^+\pi$, but also $pf_0(500)$, $pf_0(980)$, and $pf_2(1270)$ contribute to the reaction., Comment: 28 pages, 17 figures, 7 tables
Published: 2015

16. The polarization observables T, P, and H and their impact on $\gamma p \to p\pi^0$ multipoles

Author: Hartmann, J., Dutz, H., Anisovich, A. V., Bayadilov, D., Beck, R., Becker, M., Beloglazov, Y., Berlin, A., Bichow, M., Böse, S., Brinkmann, K. -Th., Crede, V., Dieterle, M., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Grüner, M., Görtz, St., Gutz, E., Hammann, Ch., Hannappel, J., Hannen, V., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Nanova, M., Nikonov, V., Novinski, D., Novotny, R., Piontek, D., Reeve, S., Rosenbaum, Ch., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thämer, Ph., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Witthauer, L.
Subjects: Nuclear Theory, Nuclear Experiment
Abstract: Data on the polarization observables T, P, and H for the reaction $\gamma p\to p\pi^0$ are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. The data were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS detector. Within the Bonn-Gatchina partial wave analysis, the new polarization data lead to a significant narrowing of the error band for the multipoles for neutral-pion photoproduction.
Published: 2015

17. Photoproduction of �� Mesons off the Proton

Author: Wilson, A., Crede, V., Anisovich, A. V., Bacelar, J. C. S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Brinkmann, K. T., Castelijns, R., Dutz, H., Elsner, D., Ewald, R., Frommberger, F., Fuchs, M., Funke, Chr., Gregor, R., Gridnev, A., Gutz, E., Hannappel, J., Hillert, W., Hoffmeister, P., Horn, I., Jaegle, I., Jude, T., Junkersfeld, J., Kalinowsky, H., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Kotulla, M., Krusche, B., Lang, M., L��hner, H., Lopatin, I. V., Lugert, S., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Nikonov, V. A., Novinski, D., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Sarantsev, A. V., Schmidt, C., Schmieden, H., Shende, S., Sokhoyan, V., Sparks, N., S��le, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., and Wiedner, U.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The differential cross sections and unpolarized spin-density matrix elements for the reaction $��p\to p��$ were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the $��$ meson, $��\to��^0��$. The cross sections cover the full angular range and show the full extent of the $t$-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to $��$ photoproduction near threshold was found to be the $3/2^+$ partial wave, which is primarily due to the sub-threshold $N(1720)\,3/2^+$ resonance. At higher energies, pomeron-exchange was found to dominate whereas $��$-exchange remained small. These $t$-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the $1/2^-$, $3/2^-$, and $5/2^+$ partial waves were also found to contribute significantly., 8 pages, 5 figures, accepted for publication in Physics Letters B
Published: 2015
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18. The polarization observables T, P, and H and their impact on $��p \to p��^0$ multipoles

Author: Hartmann, J., Dutz, H., Anisovich, A. V., Bayadilov, D., Beck, R., Becker, M., Beloglazov, Y., Berlin, A., Bichow, M., B��se, S., Brinkmann, K. -Th., Crede, V., Dieterle, M., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Gr��ner, M., G��rtz, St., Gutz, E., Hammann, Ch., Hannappel, J., Hannen, V., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., K��ser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Makonyi, K., Messi, F., Metag, V., Meyer, W., M��ller, J., Nanova, M., Nikonov, V., Novinski, D., Novotny, R., Piontek, D., Reeve, S., Rosenbaum, Ch., Roth, B., Reicherz, G., Rostomyan, T., Runkel, St., Sarantsev, A., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Th��mer, Ph., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Witthauer, L.
Subjects: Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Data on the polarization observables T, P, and H for the reaction $��p\to p��^0$ are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. The data were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS detector. Within the Bonn-Gatchina partial wave analysis, the new polarization data lead to a significant narrowing of the error band for the multipoles for neutral-pion photoproduction.
Published: 2015
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19. High statistics study of the reaction $��p\to p\;2��^0$

Author: Sokhoyan, V., Gutz, E., Crede, V., van Pee, H., Anisovich, A. V., Bacelar, J. C. S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Castelijns, R., Dutz, H., Elsner, D., Ewald, R., Frommberger, F., Fuchs, M., Funke, Ch., Gregor, R., Gridnev, A. B., Hillert, W., Hoffmeister, Ph., Horn, I., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Kotulla, M., Krusche, B., Lang, M., L��hner, H., Lopatin, I. V., Lugert, S., Mertens, T., Messchendorp, J. G., Metag, V., Metsch, B., Nanova, M., Nikonov, V. A., Novinsky, D., Novotny, R., Ostrick, M., Pant, L., Pfeiffer, M., Piontek, D., Roy, A., Sarantsev, A. V., Schmidt, Ch., Schmieden, H., Seifen, T., Shende, S., S��le, A., Sumachev, V. V., Szczepanek, T., Thiel, A., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., and Wilson, A.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: The photoproduction of 2$��^0$ mesons off protons was studied with the Crystal Barrel/TAPS experiment at the electron accelerator ELSA in Bonn. The energy of photons produced in a radiator was tagged in the energy range from 600\,MeV to 2.5\,GeV. Differential and total cross sections and $p��^0��^0$ Dalitz plots are presented. Part of the data was taken with a diamond radiator producing linearly polarized photons, and beam asymmetries were derived. Properties of nucleon and $��$ resonances contributing to the $p��^0��^0$ final state were determined within the BnGa partial wave analysis. The data presented here allow us to determine branching ratios of nucleon and $��$ resonances for their decays into $p��^0��^0$ via several intermediate states. Most prominent are decays proceeding via $��(1232)��$, $N(1440)1/2^+��$, $N(1520)3/2^-��$, $N(1680)5/2^+��$, but also $pf_0(500)$, $pf_0(980)$, and $pf_2(1270)$ contribute to the reaction., 28 pages, 17 figures, 7 tables
Published: 2015
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20. Measurement of double polarisation asymmetries in $��$-photoproduction

Author: Eberhardt, H., Jude, T. C., Schmieden, H., Anisovich, A. V., Bantes, B., Bayadilov, D., Beck, R., Beloglazov, Yu., Bichow, M., Boese, S., Brinkmann, K. -Th., Challand, Th., Crede, V., Diez, F., Drexler, P., Dutz, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Gruener, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jaegle, I., Kaiser, D., Kalinowsky, H., Kalischewski, F., Kammer, S., Keshelashvili, I., Kleber, V., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Maghrbi, Y., Makonyi, K., Metag, V., Meyer, W., Mueller, J., Nanova, M., Nikonov, V., Novotny, R., Piontek, D., Reeve, S., Reicherz, G., Rostomyan, T., Runkel, S., Sarantsev, A., Schaepe, St., Schmidt, Ch., Schmitz, R., Seifen, T., Sokhoyan, V., Sumachev, V., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., and Winnebeck, A.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The first measurements of the beam-target-helicity-asymmetries $E$ and $G$ in the photoproduction of $��$-mesons off protons at the CBELSA/TAPS experiment are reported. $E$ ($G$) was measured using circularly (linearly) polarised photons and a longitudinally polarised target. $E$ was measured over the photon energy range from close to threshold ($E_��= 1108$~MeV) to $E_��= 2300$~MeV and $G$ at a single energy interval of $1108 < E_��, 6 pages, 6 figures
Published: 2015
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21. Measurement of polarisation observables in K-s(0)Sigma(+) photoproduction off the proton

Author: Ewald, R., Anisovich, A. V., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Brinkmann, K. -T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A. B., Gutz, E., Hannappel, J., Hillert, W., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T. C., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I. V., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Nikonov, V. A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Sarantsev, A. V., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Suele, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., and Research unit Nuclear & Hadron Physics
Subjects: Baryon resonances (S=C=B=0), BEAM ASYMMETRY, Meson production, CHIRAL DYNAMICS, ELECTROPRODUCTION, ELSA, ETA, THRESHOLD, Polarisation in interactions and scattering, BARYON RESONANCES, KAON PHOTOPRODUCTION, GAMMA-P, SPECTROMETER, Decays of baryons, Nuclear Experiment, Other strange mesons
Abstract: The reaction gamma p -> K-S(0)Sigma(+) is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to E-gamma = 1650 MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay Sigma(+) -> p pi(0) up to E-gamma = 2250 MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed prominent structure in the cross section near the K* thresholds is discussed. (C) 2014 The Authors. Published by Elsevier B.V.
Published: 2014

22. Measurement of polarisation observables in $K^0_s\Sigma^+$ photoproduction off the proton

Author: Ewald, R., Anisovich, A. V., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Brinkmann, K. -T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A. B., Gutz, E., Hannappel, J., Hillert, W., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T. C, Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I. V., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Nikonov, V. A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Sarantsev, A. V., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Süle, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Nuclear Experiment
Abstract: The reaction $\gamma \, p \rightarrow K^0_S\,\Sigma^+$ is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to $E_\gamma = 2250$ MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay $\Sigma^+ \rightarrow p \pi^0$ up to $E_\gamma = 1650$ MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed cusp-like structure near the $K^*$ thresholds is discussed., Comment: 6 pages, 5 figures. References [8,9,10,11] which were not on the original submission are now included
Published: 2014

23. Experimental constraints on the $��$-nucleus real potential

Author: Friedrich, S., Makonyi, K., Metag, V., Bayadilov, D., Bantes, B., Beck, R., Beloglazov, Y. A., B��se, S., Brinkmann, K. -T., Challand, Th., Crede, V., Dahlke, T., Dietz, F., Drexler, P., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Gr��ner, M., Gutz, E., Hammann, Ch., Hammann, D., Hannappel, J., Hartmann, J., Hillert, W., Hirenzaki, S., Hoffmeister, P., Honisch, Ch., Jaegle, I., Kaiser, D., Kalinowsky, H., Kammer, S., Keshelashvili, I., Kleber, V., Klein, F., Krusche, B., Lang, M., Lopatin, I. V., Maghrbi, Y., Nanova, M., Nagahiro, H., M��ller, J., Odenthal, T., Piontek, D., Rostomyan, T., Schaepe, S., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Thiel, A., Thoma, U., van Pee, H., Walther, D., Weil, J., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Zenke, F.
Subjects: Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: In a search for $��$ mesic states, the production of $��$-mesons in coincidence with forward going protons has been studied in photon induced reactions on $^{12}$C for incident photon energies of 1250 - 3100 MeV. The $��^0 ��$ pairs from decays of bound or quasi-free $��$-mesons have been measured with the CBELSA/TAPS detector system in coincidence with protons registered in the MiniTAPS forward array. Structures in the total energy distribution of the $��^0 ��$ pairs, which would indicate the population and decay of bound $��~^{11}$B states, are not observed. The $��^0 ��$ cross section of 0.3 nb/MeV/sr observed in the bound state energy regime between -100 and 0 MeV may be accounted for by yield leaking into the bound state regime because of the large in-medium width of the $��$-meson. A comparison of the measured total energy distribution with calculations suggests the real part $V_0$ of the $��~^{11}$B potential to be small and only weakly attractive with $V_0(��=��_0) = -15\pm$ 35(stat) $\pm$20(syst) MeV in contrast to some theoretical predictions of attractive potentials with a depth of 100 - 150 MeV., 13 pages, 8 figures
Published: 2014
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24. The N(1520) 3/2- helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions

Author: Hartmann, J., Dutz, H., Anisovich, A. V., Bayadilov, D., Beck, R., Becker, M., Beloglazov, Y., Berlin, A., Bichow, M., Böse, S., Brinkmann, K. -Th., Crede, V., Dieterle, M., Eberhardt, H., Elsner, D., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Grüner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hannen, V., Herick, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jahn, O., Jude, T., Käser, A., Kaiser, D., Kalinowsky, H., Kalischewski, F., Klassen, P., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Makonyi, K., Messi, F., Metag, V., Meyer, W., Müller, J., Nanova, M., Nikonov, V., Novinski, D., Novotny, R., Piontek, D., Rosenbaum, C., Roth, B., Reicherz, G., Rostomyan, T., Sarantsev, A., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thämer, Ph., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., Witthauer, L., and Wunderlich, Y.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: New data on the polarization observables T, P, and H for the reaction $\gamma p \to p\pi^0$ are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses.
Published: 2014
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25. First measurement of the helicity asymmetry for $\gamma p\rightarrow p\pi^0$ in the resonance region

Author: Gottschall, M., Anisovich, A. V., Bantes, B., Bayadilov, D., Beck, R., Bichow, M., Böse, S., Brinkmann, K. -Th., Challand, Th., Crede, V., Dietz, F., Dutz, H., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gridnev, A., Grüner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jaegle, I., Kaiser, D., Kalinowsky, H., Kammer, S., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Maghrbi, Y., Makonyi, K., Metag, V., Meyer, W., Müller, J., Nanova, M., Nikonov, V., Novotny, R., Piontek, D., Reicherz, G., Rostomyan, T., Sarantsev, A., Schaepe, St., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., and Winnebeck, A.
Subjects: Nuclear Theory, Nuclear Experiment
Abstract: The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300\,MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed which are traced to differences in the helicity amplitudes of well known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.
Published: 2013

26. Determination of the ��'-nucleus optical potential

Author: Nanova, M., Metag, V., Paryev, E. Ya., Bayadilov, D., Bantes, B., Beck, R., Beloglazov, Y. A., B��se, S., Brinkmann, K. -T., Challand, Th., Crede, V., Dahlke, T., Dietz, F., Drexler, P., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, S., Frommberger, F., Funke, Ch., Gottschall, M., Gridnev, A., Gr��ner, M., Gutz, E., Hammann, Ch., Hammann, D., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, P., Honisch, Ch., Jaegle, I., Kaiser, D., Kalinowsky, H., Kammer, S., Keshelashvili, I., Kleber, V., Klein, F., Klempt, E., Krusche, B., Lang, M., Lopatin, I. V., Maghrbi, Y., Makonyi, K., M��ller, J., Odenthal, T., Piontek, D., Schaepe, S., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Thiel, A., Thoma, U., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., Winnebeck, A., and Zenke, F.
Subjects: Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The excitation function and momentum distribution of $��^\prime$ mesons have been measured in photon induced reactions on $^{12}{}$C in the energy range of 1250-2600 MeV. The experiment was performed with tagged photon beams from the ELSA electron accelerator using the Crystal Barrel and TAPS detectors. The data are compared to model calculations to extract information on the sign and magnitude of the real part of the $��^\prime$-nucleus potential. Within the model, the comparison indicates an attractive potential of -($37 \pm 10(stat)\pm10(syst)$) MeV depth at normal nuclear matter density. Since the modulus of this depth is larger than the modulus of the imaginary part of the $��^\prime$-nucleus potential of -($10\pm2.5$) MeV, determined by transparency ratio measurements, a search for resolved $��^\prime$-bound states appears promising., 13 pages, 6 figures
Published: 2013
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27. First measurement of the helicity asymmetry for $��p\rightarrow p��^0$ in the resonance region

Author: Gottschall, M., Anisovich, A. V., Bantes, B., Bayadilov, D., Beck, R., Bichow, M., B��se, S., Brinkmann, K. -Th., Challand, Th., Crede, V., Dietz, F., Dutz, H., Eberhardt, H., Elsner, D., Ewald, R., Fornet-Ponse, K., Friedrich, St., Frommberger, F., Funke, Ch., Gridnev, A., Gr��ner, M., Gutz, E., Hammann, Ch., Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph., Honisch, Ch., Jaegle, I., Kaiser, D., Kalinowsky, H., Kammer, S., Keshelashvili, I., Klein, F., Klempt, E., Koop, K., Krusche, B., Kube, M., Lang, M., Lopatin, I., Maghrbi, Y., Makonyi, K., Metag, V., Meyer, W., M��ller, J., Nanova, M., Nikonov, V., Novotny, R., Piontek, D., Reicherz, G., Rostomyan, T., Sarantsev, A., Schaepe, St., Schmidt, Ch., Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Thiel, A., Thoma, U., Urban, M., van Pee, H., Walther, D., Wendel, Ch., Wiedner, U., Wilson, A., and Winnebeck, A.
Subjects: Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300\,MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed which are traced to differences in the helicity amplitudes of well known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.
Published: 2013
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28. Anomaly in the K-S(0)Sigma(+) photoproduction cross section off the proton at the K* threshold

Author: Ewald, R., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Brinkmann, K. -T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch, Gridnev, A. B., Gutz, E., Hillert, W., Hannappel, J., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I. V., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Suele, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch, Research unit Nuclear & Hadron Physics, and KVI - Center for Advanced Radiation Technology
Subjects: K-0-SIGMA(+), SPECTROSCOPY, Cross section, Strangeness, FRAMEWORK, ETA, Meson photoproduction, LATTICE QCD, RELATIVISTIC QUARK-MODEL, Meson-baryon interaction, STRANGE-BARYON SPECTRUM, KAON PHOTOPRODUCTION, FORCES, RESONANCES, Dynamically generated resonance
Abstract: The gamma + p -> K-0 + Sigma(+) photoproduction reaction is investigated in the energy region from threshold to E gamma = 2250 MeV. The differential cross section exhibits increasing forward-peaking with energy, but only up to the K* threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the K*Lambda and K*Sigma thresholds. (C) 2012 Published by Elsevier B.V.
Published: 2012

29. Transparency ratio in \gamma A -> \eta' A' and the in-medium \eta' width

Author: Nanova, M., Metag, V., Ramos, A., Oset, E., Jaegle, I., Makonyi, K., Brinkmann, K., Bartholomy, O., Bayadilov, D., Beloglazov, Y. A., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fuchs, M., Funke, Ch., Gregor, R., Gridnev, A. B., Gutz, E., Höffgen, S., Hoffmeister, P., Horn, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kopf, B., Krusche, B., Langheinrich, J., Löhner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Morales, C., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Süle, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The photoproduction of \eta'-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500 - 2200 MeV. The transparency ratio has been deduced and compared to theoretical calculations describing the propagation of \eta'-mesons in nuclei. The comparison indicates a width of the \eta' -meson of the order of \Gamma= 15-25 MeV at \rho =\rho_0 for an average momentum p_{\eta'} = 1050 MeV/c, at which the \eta'-meson is produced in the nuclear rest frame. The inelastic \eta' N cross section is estimated to be 3 - 10 mb. Parameterizing the photoproduction cross section of \eta'-mesons by \sigma(A) = \sigma_0 A^{\alpha}, a value of \alpha = 0.84\pm0.03 has been deduced., Comment: 14 pages, 6 figures
Published: 2012

30. Anomaly in the K^0_S Sigma^+ photoproduction cross section off the proton at the K* threshold

Author: Ewald, R., Anisovich, A. V., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Brinkmann, K. -T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A. B., Gutz, E., Hillert, W., Hannappel, J., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I. V., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Nikonov, V. A., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Sarantsev, A. V., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Süle, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The $\gamma + p \rightarrow K^0 + \Sigma^+$ photoproduction reaction is investigated in the energy region from threshold to $E_\gamma = 2250$\,MeV. The differential cross section exhibits increasing forward-peaking with energy, but only up to the $K^*$ threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the $K^*\Lambda$ and $K^*\Sigma$ thresholds. It is speculated whether this signals the turnover of the reaction mechanism from t-channel exchange below the $K^*$ production threshold to an s-channel mechanism associated with the formation of a dynamically generated $K^*$-hyperon intermediate state., Comment: 14 pages, 7 figures
Published: 2011
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31. In-medium $\omega$ mass from the $\gamma + Nb \to \pi^{0}\gamma + X$ reaction

Author: Collaboration, The The CBELSA/TAPS, Nanova, M., Metag, V., Anton, G., Bacelar, J. C. S., Bartholomy, O., Bayadilov, D., Beloglazov, Y. A., Bogendörfer, R., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fuchs, M., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Gutz, E., Höffgen, S., Hoffmeister, P., Horn, I., Hössl, J., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kopf, B., Kotulla, M., Krusche, B., Langheinrich, J., Löhner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Morales, C., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suft, G., Süle, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Weinheimer, Ch., and Wendel, Ch.
Subjects: Nuclear Experiment
Abstract: Data on the photoproduction of $\omega$ mesons on nuclei have been re-analyzed in a search for in-medium modifications. The data were taken with the Crystal Barrel(CB)/TAPS detector system at the ELSA accelerator facility in Bonn. First results from the analysis of the data set were published by D. Trnka et al. in Phys. Rev. Lett 94 (2005) 192303 \cite{david}, claiming a lowering of the $\omega$ mass in the nuclear medium by 14$%$ at normal nuclear matter density. The extracted $\omega$ line shape was found to be sensitive to the background subtraction. For this reason a re-analysis of the same data set has been initiated and a new method has been developed to reduce the background and to determine the shape and absolute magnitude of the background directly from the data. Details of the re-analysis and of the background determination are described. The $\omega$ signal on the $Nb$ target, extracted in the re-analysis, does not show a deviation from the corresponding line shape on a $LH_2$ target, measured as reference. The earlier claim of an in-medium mass shift is thus not confirmed. The sensitivity of the $\omega$ line shape to different in-medium modification scenarios is discussed., Comment: 13 pages and 11 figures, submitted for publication
Published: 2010

32. Measurement of the beam asymmetry Σ in the forward direction for γ⃗ p → p π 0

Author: Sparks, N., Crede, V., Elsner, D., Ewald, R., Frommberger, F., Funke, Chr., Gregor, R., Gridnev, A., Gutz, E., Hillert, W., Hoffmeister, P., Jaegle, I., Anisovich, A. V., Junkersfeld, J., Kalinowsky, H., Kammer, S., Klein, Frank, Klein, Friedrich, Klempt, E., Kotulla, M., Krusche, B., Löhner, H., Lopatin, I. V., Bacelar, J. C. S., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Nanova, M., Nikonov, V. A., Novinski, D., Novotny, R., Ostrick, M., Bantes, R., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Sarantsev, A. V., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Bartholomy, O., Sokhoyan, V., Süle, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Wendel, Ch., Wilson, A., Bayadilov, D., Beck, R., Beloglazov, Y. A., and Castelijns, R.
Subjects: High Energy Physics::Experiment, ddc:530, Nuclear Experiment
Abstract: Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector for photon energies between 0.92 and 1.68 GeV at the electron stretcher accelerator ELSA. The beam asymmetry Σ has been extracted for 115∘
Published: 2010

33. Photoproduction of $��$ mesons on nuclei near the production threshold

Author: Nanova, M., Weil, J., Friedrich, S., Metag, V., Mosel, U., Anton, G., Bacelar, J. C. S., Bartholomy, O., Bayadilov, D., Beloglazov, Y. A., Bogend��rfer, R., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fuchs, M., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Gutz, E., H��ffgen, S., Hoffmeister, P., Horn, I., H��ssl, J., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kopf, B., Kotulla, M., Krusche, B., Langheinrich, J., L��hner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Morales, C., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suft, G., S��le, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Weinheimer, Ch., and Wendel, Ch.
Subjects: Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The photoproduction of $��$ mesons on LH_2, C and Nb has been studied for incident photon energies from 900 to 1300 MeV using the CB/TAPS detector at ELSA. The $��$ line shape does not show any significant difference between the LH_2 and the Nb targets. The data are compared with results of transport calculations that predict a sensitivity of the $��$ line shape to in-medium modifications near the production threshold on a free nucleon of $E_��^{lab}$ = 1109 MeV.}, 5 pages, 3 figures
Published: 2010
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34. In-medium $��$ mass from the $��+ Nb \to ��^{0}��+ X$ reaction

Author: TAPS Collaboration, Nanova, M., Metag, V., Anton, G., Bacelar, J. C. S., Bartholomy, O., Bayadilov, D., Beloglazov, Y. A., Bogend��rfer, R., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fuchs, M., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Gutz, E., H��ffgen, S., Hoffmeister, P., Horn, I., H��ssl, J., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kopf, B., Kotulla, M., Krusche, B., Langheinrich, J., L��hner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Morales, C., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suft, G., S��le, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Weinheimer, Ch., and Wendel, Ch.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: Data on the photoproduction of $��$ mesons on nuclei have been re-analyzed in a search for in-medium modifications. The data were taken with the Crystal Barrel(CB)/TAPS detector system at the ELSA accelerator facility in Bonn. First results from the analysis of the data set were published by D. Trnka et al. in Phys. Rev. Lett 94 (2005) 192303 \cite{david}, claiming a lowering of the $��$ mass in the nuclear medium by 14$%$ at normal nuclear matter density. The extracted $��$ line shape was found to be sensitive to the background subtraction. For this reason a re-analysis of the same data set has been initiated and a new method has been developed to reduce the background and to determine the shape and absolute magnitude of the background directly from the data. Details of the re-analysis and of the background determination are described. The $��$ signal on the $Nb$ target, extracted in the re-analysis, does not show a deviation from the corresponding line shape on a $LH_2$ target, measured as reference. The earlier claim of an in-medium mass shift is thus not confirmed. The sensitivity of the $��$ line shape to different in-medium modification scenarios is discussed., 13 pages and 11 figures, submitted for publication
Published: 2010
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35. K(0)pi(0)Sigma(+) and K*(0)Sigma(+) photoproduction off the proton

Author: Nanova, M., Bacelar, J. C. S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fornet-Ponse, K., Fuchs, M., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Gutz, E., Hoffmeister, P., Horn, I., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kotulla, M., Krusche, B., Lang, M., Langheinrich, J., Loehner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Messchendorp, J. G., Mertens, T., Metag, V., Morales, C., Novinski, D. V., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Radkov, A., Roy, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S. V., Sokhoyan, V., Suele, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., Weinheimer, Ch., Wendel, Ch., and KVI - Center for Advanced Radiation Technology
Subjects: ENERGIES, RESONANCE, Nuclear Experiment, ELSA, ETA
Abstract: The exclusive reactions gamma p -> K*0 Sigma(+)(1189) and gamma p -> K(0)pi(0)Sigma(+)(1189), leading to the p 4p pi(0) final state, have been measured with a tagged photon beam for incident energies from threshold up to 2.5 GeV. The experiment has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were combined to a photon detector system of almost 4 pi geometrical acceptance. Differential and total cross-sections are reported. At energies close to the threshold, a. at angular distribution has been observed for the reaction gamma p -> K(0)pi(0)Sigma(+) suggesting dominant s-channel production. Sigma*(1385) and higher-lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions of the reaction gamma p -> K*(0)Sigma(+) indicates a t-channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical predictions.
Published: 2008

36. Measurement of the beam asymmetry Sigma in pi(0)eta production off the proton with the CBELSA/TAPS experiment

Author: Gutz, E., Sokhoyan, V., van Pee, H., Anisovich, A. V., Bacelar, J. C. S., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y. A., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fornet-Ponse, K., Fuchs, M., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Hoeffgen, St., Hoffmeister, P., Horn, I., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Friedrich, Klein, Frank, Klempt, E., Konrad, M., Kotulla, M., Krusche, B., Lang, M., Langheinrich, J., Loehner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J. G., Metag, V., Morales, C., Nanova, M., Nikonov, V. A., Novinsky, D., Novotny, R., Ostrick, M., Pant, L., Pfeiffer, M., Radkov, A., Sarantsev, A. V., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suele, A., Sumachev, V. V., Szczepanek, T., Thoma, U., Trnka, D., Walther, D., Weinheimer, Ch., Wendel, Ch., and KVI - Center for Advanced Radiation Technology
Subjects: RELATIVISTIC QUARK-MODEL, STRANGE-BARYON SPECTRUM, PHOTOPRODUCTION, FORCES, Nuclear Experiment, ELSA
Abstract: In photoproduction experiments, a large number of final states yielding various resonance contributions are accessible. To extract resonance parameters via partial-wave analysis not only the measurement of differential cross-sections is necessary, but also the determination of polarization observables. At the electron accelerator ELSA (Bonn) the coherent bremsstrahlung method was used to generate a linearly polarized photon beam. Using the CBELSA/TAPS detector setup, the beam asymmetry Sigma in the reaction gamma p -> p pi(0) eta was determined as a function of various masses and angles for photon energies between 970MeV and 1650MeV.
Published: 2008

37. Modification of the $��$-Meson Lifetime in Nuclear Matter

Author: Kotulla, M., Trnka, D., M��hlich, P., Anton, G., Bacelar, J. C. S., Bartholomy, O., Bayadilov, D., Beloglazov, Y. A., Bogend��rfer, R., Castelijns, R., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Ewald, R., Fabry, I., Fuchs, M., Essig, K., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A. B., Gutz, E., H��ffgen, S., Hoffmeister, P., Horn, I., H��ssl, J., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Fritz, Klempt, E., Konrad, M., Kopf, B., Krusche, B., Langheinrich, J., L��hner, H., Lopatin, I. V., Lotz, J., Lugert, S., Menze, D., Messchendorp, J. G., Mertens, T., Metag, V., Mosel, U., Nanova, M., Novotny, R., Ostrick, M., Pant, L. M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suft, G., Sumachev, V. V., Szczepanek, T., S��le, A., Thoma, U., Varma, R., Walther, D., Weinheimer, Ch., and Wendel, Ch.
Subjects: Nuclear Theory (nucl-th), High Energy Physics - Phenomenology (hep-ph), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The photo production of $��$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $��$ meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic $��$ width is found to be $130-150 \rm{MeV/c^2}$ at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the $��$ meson, this inelastic $��$ width corresponds to a reduction of the $��$ lifetime by a factor $\approx 30$. For the first time, the momentum dependent $��$N cross section has been extracted from the experiment and is in the range of 70 mb., 5 pages, 4 figures
Published: 2008
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38. First observation of in-medium modifications of the omega meson

Author: Trnka, D., Anton, G., Bacelar, J.C.S, Bartholomy, O., Bayadilov, D., Beloglazov, Y.A., Bogendorfer, R., Castelijns, R.J.J., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Ewald, R., Fabry, I., Fuchs, M., Essig, K., Funke, Ch., Gothe, R., Gregor, R., Gridnev, A., Gutz, E., Hoffgen, S.K., Hoffmeister, P., Horn, I., Hössl, J., Jaegle, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Fritz, Klempt, E., Konrad, M., Kopf, B., Kotulla, M., Krusche, B., Langheinrich, J., Löhner, H., Lopatin, I., Lotz, J., Lugert, S., Menze, D.W., Messchendorp, J.G., Mertens, T., Metag, V., Morales, C., Nanova, M., Novotny, R., Ostrick, M., Pant, L.M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Shende, S., Suft, G., Sumachev, V., Szczepanek, T., Sule, A., Thoma, U., Varma, R., Walther, D., Weinheimer, Ch., Wendel, Ch., and KVI - Center for Advanced Radiation Technology
Subjects: JONA-LASINIO MODEL, deuteron, +pi0+photon%22">omega(783) --> pi0 photon, Nuclear Theory, FOS: Physical sciences, (pi0 photon) [mass spectrum], +omega%28783%29+anything%22">photon nucleus --> omega(783) anything, 0.64-2.53 GeV, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), ddc:550, Bonn ELSA Stor, SPECTROMETER, density [nuclear matter], Nuclear Experiment (nucl-ex), Nuclear Experiment, AU COLLISIONS, mass [omega(783)], NUCLEI, PAIRS, momentum [omega(783)], radiative decay [omega(783)], High Energy Physics::Experiment, photoproduction [omega(783)], inclusive reaction [photon nucleus], NAMBU, niobium, VECTOR-MESONS, MATTER, experimental results
Abstract: The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction A(gamma, omega)X. Results obtained for Nb are compared to a reference measurement on a liquid hydrogen target. While for recoiling, long-lived mesons (pi, eta and etaprime), which decay outside of the nucleus, a difference in the lineshape for the two data samples is not observed, we find a significant enhancement towards lower masses for omega mesons with low momenta produced on the Nb target., Comment: Latex, 4 pages, 4 figures, accepted by Phys. Rev. Lett; references re-arranged, now references in chronological order in first paragraph
Published: 2005
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39. Anomaly in the KS0Σ+ photoproduction cross section off the proton at the K⁎ threshold

Author: Ewald, R., Bantes, B., Bartholomy, O., Bayadilov, D., Beck, R., Beloglazov, Y.A., Brinkmann, K.-T., Crede, V., Dutz, H., Elsner, D., Fornet-Ponse, K., Frommberger, F., Funke, Ch., Gridnev, A.B., Gutz, E., Hillert, W., Hannappel, J., Hoffmeister, P., Jaegle, I., Jahn, O., Jude, T., Junkersfeld, J., Kalinowsky, H., Kammer, S., Kleber, V., Klein, Frank, Klein, Friedrich, Klempt, E., Krusche, B., Lang, M., Löhner, H., Lopatin, I.V., Menze, D., Mertens, T., Messchendorp, J.G., Metag, V., Nanova, M., Novinski, D., Novotny, R., Ostrick, M., Pant, L., van Pee, H., Roy, A., Schadmand, S., Schmidt, C., Schmieden, H., Schoch, B., Shende, S., Sokhoyan, V., Süle, A., Sumachev, V.V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Cross section, Strangeness, Meson–baryon interaction, Meson photoproduction, Dynamically generated resonance
Abstract: The γ+p→K0+Σ+ photoproduction reaction is investigated in the energy region from threshold to Eγ=2250 MeV. The differential cross section exhibits increasing forward-peaking with energy, but only up to the K⁎ threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the K⁎Λ and K⁎Σ thresholds.
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40. Transparency ratio in γA→η′A′ and the in-medium η′ width

Author: Nanova, M., Metag, V., Ramos, A., Oset, E., Jaegle, I., Makonyi, K., Brinkmann, K., Bartholomy, O., Bayadilov, D., Beloglazov, Y.A., Crede, V., Dutz, H., Ehmanns, A., Elsner, D., Essig, K., Ewald, R., Fabry, I., Fuchs, M., Funke, Ch., Gregor, R., Gridnev, A.B., Gutz, E., Höffgen, S., Hoffmeister, P., Horn, I., Junkersfeld, J., Kalinowsky, H., Klein, Frank, Klein, Friedrich, Klempt, E., Konrad, M., Kopf, B., Krusche, B., Langheinrich, J., Löhner, H., Lopatin, I.V., Lotz, J., Lugert, S., Menze, D., Mertens, T., Messchendorp, J.G., Morales, C., Novotny, R., Ostrick, M., Pant, L.M., van Pee, H., Pfeiffer, M., Roy, A., Radkov, A., Schadmand, S., Schmidt, Ch., Schmieden, H., Schoch, B., Süle, A., Sumachev, V.V., Szczepanek, T., Thoma, U., Trnka, D., Varma, R., Walther, D., and Wendel, Ch.
Subjects: Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The photoproduction of η′-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500–2200 MeV. The transparency ratio has been deduced and compared to theoretical calculations describing the propagation of η′-mesons in nuclei. The comparison indicates a width of the η′-meson of the order of Γ=15–25 MeV at ρ=ρ0 for an average momentum pη′=1050 MeV/c, at which the η′-meson is produced in the nuclear rest frame. The inelastic η′N cross section is estimated to be 3–10 mb. Parameterizing the photoproduction cross section of η′-mesons by σ(A)=σ0Aα, a value of α=0.84±0.03 has been deduced.
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41. Right-to-left interatrial shunt secondary to an extensive right ventricular myocardial infarction

Author: Wendel Ch, Claude R. Joyner, and Sinda B. Dianzumba
Subjects: medicine.medical_specialty, Right-to-left shunt, Myocardial Infarction, Hemodynamics, Heart Septal Defects, Atrial, Hypoxemia, Diagnosis, Differential, Electrocardiography, medicine.artery, Internal medicine, medicine, Humans, Myocardial infarction, medicine.diagnostic_test, business.industry, General Medicine, Middle Aged, medicine.disease, Echocardiography, Cardiology, Patent foramen ovale, Female, Abnormality, medicine.symptom, Cardiology and Cardiovascular Medicine, Complication, business
Abstract: This case report describes a rare complication of right ventricular myocardial infarction. Hypoxemia in this setting has only been described in two previous cases with a right-to-left interatrial shunt. This is surprising, given the high incidence of probe patent foramen ovale in randomly selected necropsy cases. Two-dimensional echocardiography with contrast is the method of choice for detecting this abnormality.
Published: 1985

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