Measurement of the helicity dependence for single π0 photoproduction from the deuteron

Cividini, F. et al. (2022) Measurement of the helicity dependence for single π0 photoproduction from the deuteron. European Physical Journal A, 58(6), 113. (doi: 10.1140/epja/s10050-022-00760-4)

Abstract

The helicity-dependent single π0 photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π0 production off the proton and the neutron have been measured, for the first time, from the threshold region up to the photon energy 1.4 GeV. The experiment was performed at the tagged photon facility of the MAMI accelerator and used a circularly polarised photon beam and longitudinally polarised deuteron target. The reaction products were detected using the large acceptance Crystal Ball/TAPS calorimeter, which covered 97% of the full solid angle. Comparing the cross section from the deuteron with the sum of free nucleon cross sections provides a quantitative estimate of the effects of the nuclear medium on pion production. In contrast, comparison of the E helicity asymmetry data from quasi-free protons off deuterium with data from a free proton target indicates that nuclear effects do not significantly affect this observable. As a consequence, it is deduced that the helicity asymmetry E on a free neutron can be reliably extracted from measurements on a deuteron in quasi-free kinematics.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Powell, Abby-Rhian and MULLEN, CHRISTOPHER and Glazier, Dr Derek and MacGregor, Professor Ian and Livingston, Dr Kenneth and Gardner, Mr Simon and Annand, Dr John
• Authors: Cividini, F., Dieterle, M., Abt, S., Achenbach, P., Adlarson, P., Afzal, F., Ahmed, Z., Annand, J. R. M., Arends, H. J., Bashkanov, M., Beck, R., Biroth, M., Borisov, N., Braghieri, A., Briscoe, W. J., Collicott, C., Costanza, S., Denig, A., Dolzhikov, A. S., Downie, E. J., Drexler, P., Fegan, S., Fix, A., Gardner, S., Ghosal, D., Glazier, D. I., Gorodnov, I., Gradl, W., Günther, M., Gurevich, D., Heijkenskjöld, L., Hornidge, D., Huber, G. M., Käser, A., Kashevarov, V. L., Kay, S. J. D., Korolija, M., Krusche, B., Lazarev, A., Livingston, K., Lutterer, S., MacGregor, I. J. D., Manley, D. M., Martel, P. P., Miskimen, R., Mocanu, M., Mornacchi, E., Mullen, C., Neganov, A., Neiser, A., Ostrick, M., Paudyal, D., Pedroni, P., Powell, A., Rostomyan, T., Sokhoyan, V., Spieker, K., Steffen, O., Strakovsky, I., Strub, T., Thiel, A., Thiel, M., Thomas, A., Usov, Y. A., Wagner, S., Watts, D. P., Werthmüller, D., Wettig, J., Witthauer, L., Wolfes, M., and Zachariou, N.
• Subjects: Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Research Group: NPE
• Journal Name: European Physical Journal A
• Journal Abbr.: EPJA
• Publisher: Springer
• ISSN: 1434-6001
• ISSN (Online): 1434-601X
• Published Online: 30 June 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in European Physical Journal A 58(6): 113
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

Related URLs

• Pre-print