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Your search keyword '"Krambrich, D."' showing total 4 results
Start Over Author "Krambrich, D." Topic nuclear theory
4 results on '"Krambrich, D."'

1. Neutron skin of $^{208}$Pb from Coherent Pion Photoproduction

Author

Tarbert, C. M., Watts, D. P., Glazier, D. I., Aguar, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Beck, R., Bekrenev, V., Boillat, B., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Codling, R., Downie, E. J., Foehl, K., Grabmayr, P., Gregor, R., Heid, E., Hornidge, D., Jahn, O., Kashevarov, V. L., Knezevic, A., Kondratiev, R., Korolija, M., Kotulla, M., Krambrich, D., Krusche, B., Lang, M., Lisin, V., Livingston, K., Lugert, S., MacGregor, I. J. D., Manley, D. M., Martinez, M., McGeorge, J. C., Mekterovic, D., Metag, V., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Owens, R. O., Pedroni, P., Polonski, A., Prakhov, S. N., Price, J. W., Rosner, G., Rost, M., Rostomyan, T., Schadmand, S., Schumann, S., Sober, D., Starostin, A., Supek, I., Thomas, A., Unverzagt, M., Walcher, Th., and Zehr, F.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Information on the size and shape of the neutron skin on $^{208}$Pb has been extracted from coherent pion photoproduction cross sections measured using the Crystal Ball together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections the half-height radius and diffuseness of the neutron distribution are found to be 6.70$\pm 0.03(stat)$ fm and 0.55$\pm 0.01(stat)$$^{+0.02}_{-0.03}(sys)$ fm respectively, corresponding to a neutron skin thickness $\Delta r_{np}$=0.15$\pm 0.03(stat)$$^{+0.01}_{-0.03}(sys)$ fm. The results give the first successful extraction of a neutron skin with an electromagnetic probe and indicate the skin of $^{208}$Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter., Comment: 4 figures 5 pages. Version submitted to journal. Includes additional studies of systematic effects in the extracted diffuseness, which led to a small increase in the quoted systematic error. These additional studies are discussed in the revised manuscript. Also includes minor editorial improvements to the text

Published
2013
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2. Measurement of the pi^+ meson polarizabilities via the gamma p->gamma pi^+ n reaction

Author

Ahrens, J., Alexeev, V. M., Annand, J. R. M., Arends, H. J., Beck, R., Caselotti, G., Cherepnya, S. N., Drechsel, D., Fil'kov, L. V., F"ohl, K., Giller, I., Grabmayr, P., Hehl, T., Hornidge, D., Kashevarov, V. L., Kotulla, M., Krambrich, D., Krusche, B., Lang, M., McGeorge, J. C., MacGregor, I. J. D., Metag, V., Moinester, M., Novotny, R., Pfeiffer, M., Rost, M., Schadmand, S., Scherer, S., Thomas, A., Unkmeir, C., and Walcher, Th.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Theory
Abstract

An experiment on the radiative pi^+ meson photoproduction from the proton (gamma p->gamma pi^+ n) was carried out at the Mainz Microtron MAMI in the kinematic region 537 MeV

Published
2004
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3. Coherent photoproduction of π0- and η-mesons off 7Li

Author

Maghrbi, Y., Krusche, B., Ahrens, J., Annand, J. R. M., Arends, H. J., Beck, R., Bekrenev, V., Boillat, B., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Codling, R. F. B., Downie, E. J., Drexler, P., Fil’kov, L. V., Fix, A., Glazier, D. I., Gregor, R., Heid, E., Hornidge, D., Jaegle, I., Jahn, O., Kashevarov, V. L., Keshelashvili, I., Knezevic, A., Kondratiev, R., Korolija, M., Krambrich, D., Lang, M., Lisin, V., Livingston, K., Lugert, S., MacGregor, I. J. D., Manley, D. M., Martinez, M., McGeorge, J. C., Mekterovic, D., Metag, V., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Ostrick, M., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S., Price, J. W., Rosner, G., Rost, M., Rostomyan, T., Schadmand, S., Schumann, S., Sober, D., Starostin, A., Supek, I., Tarbert, C. M., Thomas, A., Unverzagt, M., Watts, D. P., Werthmüller, D., and Zehr, F.

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

Coherent photoproduction of π0-mesons from threshold (E th ≈ 136 MeV) throughout the Δ-resonance region and of η-mesons close to the production threshold (E th ≈ 570 MeV for η has been measured for 7Li nuclei. The experiment was performed using the tagged-photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4π solid-angle electromagnetic calorimeter. The reactions were identified by a combined invariant-mass and missing-energy analysis. A comparison of the pion data to plane-wave impulse modelling tests the nuclear mass form factor. So far coherent η production had been only identified for the lightest nuclear systems (2H and 3He . For 3He a large enhancement of the cross section above plane-wave approximations had been reported, indicating the formation of a quasi-bound state. The present Li data for η production agree with a plane-wave approximation. Contrary to 3He , neither a threshold enhancement of the total cross section nor a deviation of the angular distributions from the expected form factor dependence were observed

Published
2013

4. Incoherent pion photoproduction on $^{12}$C

Author

Tarbert, C. M., Watts, D. P., Aguar, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Beck, R., Bekrenev, V., Boillat, B., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Codling, R., Downie, E. J., Foehl, K., Glazier, D. I., Grabmayr, P., Gregor, R., Heid, E., Hornidge, D., Jahn, O., Kashevarov, V. L., Knezevic, A., Kondratiev, R., Korolija, M., Kotulla, M., Krambrich, D., Krusche, B., Lang, M., Lisin, V., Livingston, K., Lugert, S., MacGregor, I. J. D., Manley, D. M., Martinez, M., McGeorge, J. C., Mekterovic, D., Metag, V., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Owens, R. O., Pedroni, P., Polonski, A., Prakhov, S. N., Price, J. W., Rosner, G., Rost, M., Rostomyan, T., Schadmand, S., Schumann, S., Sober, D., Starostin, A., Supek, I., Thomas, A., Unverzagt, M., Walcher, Th., and Zehr, F.

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

We present the first detailed measurement of incoherent photoproduction of neutral pions to a discrete state of a residual nucleus. The $^{12}$C$(\gamma,\pi^{0})^{12}$C$^{*}_{4.4MeV}$ reaction has been studied with the Glasgow photon tagger at MAMI employing a new technique which uses the large solid angle Crystal Ball detector both as a $\pi^{0}$ spectrometer and to detect decay photons from the excited residual nucleus. The technique has potential applications to a broad range of future nuclear measurements with the Crystal Ball and similar detector systems elsewhere. The data are sensitive to the propagation of the $\Delta$ in the nuclear medium and will give the first information on matter transition form factors from measurements with an electromagnetic probe. The incoherent cross sections are compared to two theoretical predictions including a $\Delta$-hole model., Comment: 4 pages, 8 figures, submitted to Physical Review Letters

Published
2007
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