Neutron polarisation transfer, Cx′, in π+ photoproduction off the proton, d(γ⊙,n→π+)nspec

(A2 Collaboration at MAMI)

doi:10.1016/j.physletb.2023.138283

Neutron polarisation transfer, C_x^′, in π⁺ photoproduction off the proton, d(γ^⊙,n→π⁺)n_spec

(A2 Collaboration at MAMI)

Physics

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

Abstract

We report a first measurement of the double-polarisation observable, C_x^′, in π⁺ photoproduction off the proton. The C_x^′ double-polarisation observable represents the transfer of polarisation from a circularly polarised photon beam to the recoiling neutron. The MAMI circularly polarised photon beam impinged on a liquid deuterium target cell, with reaction products detected in the Crystal Ball calorimeter. Ancillary apparatus surrounding the target provided tracking, particle identification and determination of recoil nucleon polarisation. The C_x^′ observable is determined for photon energies 800-1400 MeV, providing new constraints on models aiming to elucidate the spectrum and properties of nucleon resonances. This is the first determination of any polarisation observable from the beam-recoil group of observables for this reaction. Inclusion of the new data in the database of the SAID partial wave analysis shifted the solution to a new global minima which, not only gives better agreement with the current data, but also improves the description of a range of other single and double polarisation observables for charged pion photoproduction.

Original language	English
Article number	138283
Number of pages	7
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	847
DOIs	https://doi.org/10.1016/j.physletb.2023.138283
Publication status	Published - 10 Dec 2023

Bibliographical note

© 2023 The Authors. Published by Elsevier B.V.

Funding Information:
In accordance with UK data management policy, all data are available for downloading from PURE [34] . This work has been supported by the U.K. STFC ( ST/V002570/1 , ST/L00478X/2 , ST/V001035/1 , ST/P004385/2 , ST/T002077/1 , ST/L005824/1 , 57071/1 , 50727/1 ) 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-SC0016583 , DE-SC0016582 , 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 , PHY-2012940 ), INFN (Italy), and NSERC of Canada (Grant No. FRN-SAPPJ2015-00023 ). This infrastructure is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 824093 .

Keywords

Photoproduction

Access to Document

10.1016/j.physletb.2023.138283Licence: CC BY

1-s2.0-S0370269323006172-main
© 2023 The Authors. Published by Elsevier B.V
Final published version, 928 KBLicence: CC BY

Cite this

@article{219b6d40ae1b48e8b934b34c0715a4b0,

title = "Neutron polarisation transfer, Cx′, in π+ photoproduction off the proton, d(γ⊙,n→π+)nspec",

abstract = "We report a first measurement of the double-polarisation observable, Cx′, in π+ photoproduction off the proton. The Cx′ double-polarisation observable represents the transfer of polarisation from a circularly polarised photon beam to the recoiling neutron. The MAMI circularly polarised photon beam impinged on a liquid deuterium target cell, with reaction products detected in the Crystal Ball calorimeter. Ancillary apparatus surrounding the target provided tracking, particle identification and determination of recoil nucleon polarisation. The Cx′ observable is determined for photon energies 800-1400 MeV, providing new constraints on models aiming to elucidate the spectrum and properties of nucleon resonances. This is the first determination of any polarisation observable from the beam-recoil group of observables for this reaction. Inclusion of the new data in the database of the SAID partial wave analysis shifted the solution to a new global minima which, not only gives better agreement with the current data, but also improves the description of a range of other single and double polarisation observables for charged pion photoproduction.",

keywords = "Photoproduction",

author = "{(A2 Collaboration at MAMI)} and M. Bashkanov and Watts, {D. P.} and Kay, {S. J.D.} and S. Abt and P. Achenbach and P. Adlarson and F. Afzal and Z. Ahmed and Akondi, {C. S.} and Annand, {J. R.M.} and R. Beck and M. Biroth and N. Borisov and A. Braghieri and Briscoe, {W. J.} and F. Cividini and C. Collicott and S. Costanza and A. Denig 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 D. Gurevich and L. Heijkenskj{\"o}ld and D. Hornidge and Huber, {G. M.} and Kashevarov, {V. L.} 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 E. Mornacchi and C. Mullen and A. Neganov and A. Neiser and M. Ostrick and Otte, {P. B.} and D. Paudyal and N. Zachariou",

note = "{\textcopyright} 2023 The Authors. Published by Elsevier B.V. Funding Information: In accordance with UK data management policy, all data are available for downloading from PURE [34] . This work has been supported by the U.K. STFC ( ST/V002570/1 , ST/L00478X/2 , ST/V001035/1 , ST/P004385/2 , ST/T002077/1 , ST/L005824/1 , 57071/1 , 50727/1 ) 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-SC0016583 , DE-SC0016582 , 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 , PHY-2012940 ), INFN (Italy), and NSERC of Canada (Grant No. FRN-SAPPJ2015-00023 ). This infrastructure is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 824093 . ",

year = "2023",

month = dec,

day = "10",

doi = "10.1016/j.physletb.2023.138283",

language = "English",

volume = "847",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

}

TY - JOUR

T1 - Neutron polarisation transfer, Cx′, in π+ photoproduction off the proton, d(γ⊙,n→π+)nspec

AU - (A2 Collaboration at MAMI)

AU - Bashkanov, M.

AU - Watts, D. P.

AU - Kay, S. J.D.

AU - Abt, S.

AU - Achenbach, P.

AU - Adlarson, P.

AU - Afzal, F.

AU - Ahmed, Z.

AU - Akondi, C. S.

AU - Annand, J. R.M.

AU - Beck, R.

AU - Biroth, M.

AU - Borisov, N.

AU - Braghieri, A.

AU - Briscoe, W. J.

AU - Cividini, F.

AU - Collicott, C.

AU - Costanza, S.

AU - Denig, A.

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 - Gurevich, D.

AU - Heijkenskjöld, L.

AU - Hornidge, D.

AU - Huber, G. M.

AU - Kashevarov, V. L.

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 - Mornacchi, E.

AU - Mullen, C.

AU - Neganov, A.

AU - Neiser, A.

AU - Ostrick, M.

AU - Otte, P. B.

AU - Paudyal, D.

AU - Zachariou, N.

N1 - © 2023 The Authors. Published by Elsevier B.V. Funding Information: In accordance with UK data management policy, all data are available for downloading from PURE [34] . This work has been supported by the U.K. STFC ( ST/V002570/1 , ST/L00478X/2 , ST/V001035/1 , ST/P004385/2 , ST/T002077/1 , ST/L005824/1 , 57071/1 , 50727/1 ) 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-SC0016583 , DE-SC0016582 , 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 , PHY-2012940 ), INFN (Italy), and NSERC of Canada (Grant No. FRN-SAPPJ2015-00023 ). This infrastructure is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 824093 .

PY - 2023/12/10

Y1 - 2023/12/10

N2 - We report a first measurement of the double-polarisation observable, Cx′, in π+ photoproduction off the proton. The Cx′ double-polarisation observable represents the transfer of polarisation from a circularly polarised photon beam to the recoiling neutron. The MAMI circularly polarised photon beam impinged on a liquid deuterium target cell, with reaction products detected in the Crystal Ball calorimeter. Ancillary apparatus surrounding the target provided tracking, particle identification and determination of recoil nucleon polarisation. The Cx′ observable is determined for photon energies 800-1400 MeV, providing new constraints on models aiming to elucidate the spectrum and properties of nucleon resonances. This is the first determination of any polarisation observable from the beam-recoil group of observables for this reaction. Inclusion of the new data in the database of the SAID partial wave analysis shifted the solution to a new global minima which, not only gives better agreement with the current data, but also improves the description of a range of other single and double polarisation observables for charged pion photoproduction.

AB - We report a first measurement of the double-polarisation observable, Cx′, in π+ photoproduction off the proton. The Cx′ double-polarisation observable represents the transfer of polarisation from a circularly polarised photon beam to the recoiling neutron. The MAMI circularly polarised photon beam impinged on a liquid deuterium target cell, with reaction products detected in the Crystal Ball calorimeter. Ancillary apparatus surrounding the target provided tracking, particle identification and determination of recoil nucleon polarisation. The Cx′ observable is determined for photon energies 800-1400 MeV, providing new constraints on models aiming to elucidate the spectrum and properties of nucleon resonances. This is the first determination of any polarisation observable from the beam-recoil group of observables for this reaction. Inclusion of the new data in the database of the SAID partial wave analysis shifted the solution to a new global minima which, not only gives better agreement with the current data, but also improves the description of a range of other single and double polarisation observables for charged pion photoproduction.

KW - Photoproduction

UR - http://www.scopus.com/inward/record.url?scp=85175145626&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2023.138283

DO - 10.1016/j.physletb.2023.138283

M3 - Article

AN - SCOPUS:85175145626

SN - 0370-2693

VL - 847

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 138283

ER -

Neutron polarisation transfer, C_x^′, in π⁺ photoproduction off the proton, d(γ^⊙,n→π⁺)n_spec

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

Nuclear Physics Consolidated Grant 2021-2024

Cite this

Neutron polarisation transfer, Cx′, in π+ photoproduction off the proton, d(γ⊙,n→π+)nspec

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

Projects

Nuclear Physics Consolidated Grant 2021-2024

Cite this

Neutron polarisation transfer, C_x^′, in π⁺ photoproduction off the proton, d(γ^⊙,n→π⁺)n_spec