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

The A2 Collaboration at MAMI

doi:10.1140/epja/s10050-022-00760-4

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

The A2 Collaboration at MAMI

Research output: Contribution to journal › Article › peer-review

Abstract

The helicity-dependent single π photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π 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.

Original language	English
Article number	113
Journal	European Physical Journal A
Volume	58
Issue number	6
DOIs	https://doi.org/10.1140/epja/s10050-022-00760-4
Publication status	Published - 30 Jun 2022

Bibliographical note

Funding Information:
The authors wish to acknowledge the excellent support of the accelerator group of MAMI. This work has been supported by the U.K. STFC (ST/L00478X/1, ST/T002077/1, ST/L005824/1, 57071/1, 50727/1, ST/V001035/1) grants, the Deutsche Forschungsgemeinschaft (SFB443, SFB/TR16, and SFB1044), DFG-RFBR (Grant no. 09-02-91330), Schweizerischer Nationalfonds (Contracts No. 200020-175807, No. 200020-156983, No. 132799, No. 121781, No. 117601), the U.S. Department of Energy (Offices of Science and Nuclear Physics, Awards No. DE-SC0014323, DEFG02-99-ER41110, No. DE-FG02-88ER40415, No. DEFG02-01-ER41194) and National Science Foundation (Grants NSF OISE-1358175; PHY-1039130, PHY-1714833, No. IIA-1358175), INFN (Italy), and NSERC of Canada (Grant no. FRN-SAPPJ2015-00023).

Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.

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10.1140/epja/s10050-022-00760-4

Cite this

@article{3f884f07603c48bf86e7f0639ffb60c8,

title = "Measurement of the helicity dependence for single π photoproduction from the deuteron",

abstract = "The helicity-dependent single π photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π 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.",

author = "{The A2 Collaboration at MAMI} and F. Cividini and M. Dieterle and S. Abt and P. Achenbach and P. Adlarson and F. Afzal and Z. Ahmed and Annand, {J. R.M.} and Arends, {H. J.} and M. Bashkanov and R. Beck and M. Biroth and N. Borisov and A. Braghieri and Briscoe, {W. J.} and C. Collicott and S. Costanza and A. Denig and Dolzhikov, {A. S.} and Downie, {E. J.} and P. Drexler and S. Fegan and A. Fix and S. Gardner and D. Ghosal and Glazier, {D. I.} and I. Gorodnov and W. Gradl and M. G{\"u}nther and D. Gurevich and L. Heijkenskj{\"o}ld and D. Hornidge and Huber, {G. M.} and A. K{\"a}ser and Kashevarov, {V. L.} and Kay, {S. J.D.} and M. Korolija and B. Krusche and A. Lazarev and K. Livingston and S. Lutterer and MacGregor, {I. J.D.} and Manley, {D. M.} and Martel, {P. P.} and R. Miskimen and M. Mocanu and E. Mornacchi and Watts, {D. P.} and D. Werthm{\"u}ller and N. Zachariou",

note = "Funding Information: The authors wish to acknowledge the excellent support of the accelerator group of MAMI. This work has been supported by the U.K. STFC (ST/L00478X/1, ST/T002077/1, ST/L005824/1, 57071/1, 50727/1, ST/V001035/1) grants, the Deutsche Forschungsgemeinschaft (SFB443, SFB/TR16, and SFB1044), DFG-RFBR (Grant no. 09-02-91330), Schweizerischer Nationalfonds (Contracts No. 200020-175807, No. 200020-156983, No. 132799, No. 121781, No. 117601), the U.S. Department of Energy (Offices of Science and Nuclear Physics, Awards No. DE-SC0014323, DEFG02-99-ER41110, No. DE-FG02-88ER40415, No. DEFG02-01-ER41194) and National Science Foundation (Grants NSF OISE-1358175; PHY-1039130, PHY-1714833, No. IIA-1358175), INFN (Italy), and NSERC of Canada (Grant no. FRN-SAPPJ2015-00023). Publisher Copyright: {\textcopyright} 2022, The Author(s), under exclusive licence to Societ{\`a} Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.",

year = "2022",

month = jun,

day = "30",

doi = "10.1140/epja/s10050-022-00760-4",

language = "English",

volume = "58",

journal = "European Physical Journal A",

issn = "1434-6001",

publisher = "Springer",

number = "6",

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TY - JOUR

T1 - Measurement of the helicity dependence for single π photoproduction from the deuteron

AU - The A2 Collaboration at MAMI

AU - Cividini, F.

AU - Dieterle, M.

AU - Abt, S.

AU - Achenbach, P.

AU - Adlarson, P.

AU - Afzal, F.

AU - Ahmed, Z.

AU - Annand, J. R.M.

AU - Arends, H. J.

AU - Bashkanov, M.

AU - Beck, R.

AU - Biroth, M.

AU - Borisov, N.

AU - Braghieri, A.

AU - Briscoe, W. J.

AU - Collicott, C.

AU - Costanza, S.

AU - Denig, A.

AU - Dolzhikov, A. S.

AU - Downie, E. J.

AU - Drexler, P.

AU - Fegan, S.

AU - Fix, A.

AU - Gardner, S.

AU - Ghosal, D.

AU - Glazier, D. I.

AU - Gorodnov, I.

AU - Gradl, W.

AU - Günther, M.

AU - Gurevich, D.

AU - Heijkenskjöld, L.

AU - Hornidge, D.

AU - Huber, G. M.

AU - Käser, A.

AU - Kashevarov, V. L.

AU - Kay, S. J.D.

AU - Korolija, M.

AU - Krusche, B.

AU - Lazarev, A.

AU - Livingston, K.

AU - Lutterer, S.

AU - MacGregor, I. J.D.

AU - Manley, D. M.

AU - Martel, P. P.

AU - Miskimen, R.

AU - Mocanu, M.

AU - Mornacchi, E.

AU - Watts, D. P.

AU - Werthmüller, D.

AU - Zachariou, N.

N1 - Funding Information: The authors wish to acknowledge the excellent support of the accelerator group of MAMI. This work has been supported by the U.K. STFC (ST/L00478X/1, ST/T002077/1, ST/L005824/1, 57071/1, 50727/1, ST/V001035/1) grants, the Deutsche Forschungsgemeinschaft (SFB443, SFB/TR16, and SFB1044), DFG-RFBR (Grant no. 09-02-91330), Schweizerischer Nationalfonds (Contracts No. 200020-175807, No. 200020-156983, No. 132799, No. 121781, No. 117601), the U.S. Department of Energy (Offices of Science and Nuclear Physics, Awards No. DE-SC0014323, DEFG02-99-ER41110, No. DE-FG02-88ER40415, No. DEFG02-01-ER41194) and National Science Foundation (Grants NSF OISE-1358175; PHY-1039130, PHY-1714833, No. IIA-1358175), INFN (Italy), and NSERC of Canada (Grant no. FRN-SAPPJ2015-00023). Publisher Copyright: © 2022, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.

PY - 2022/6/30

Y1 - 2022/6/30

N2 - The helicity-dependent single π photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π 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.

AB - The helicity-dependent single π photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π 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.

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U2 - 10.1140/epja/s10050-022-00760-4

DO - 10.1140/epja/s10050-022-00760-4

M3 - Article

AN - SCOPUS:85134061275

SN - 1434-6001

VL - 58

JO - European Physical Journal A

JF - European Physical Journal A

IS - 6

M1 - 113

ER -

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

Abstract

Bibliographical note

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Nuclear Physics Consolidated Grant 2021-2024

Shining a light on strangeness

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

Abstract

Bibliographical note

Access to Document

Other files and links

Projects

Nuclear Physics Consolidated Grant 2021-2024

Shining a light on strangeness

Cite this