First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons
The helicity-dependent cross sections for the photoproduction of π0η pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball – TAPS calorimeter. The experiment used a polarized deuterated but...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2018-11-01
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| Series: | Physics Letters B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269318307639 |
| _version_ | 1811257383163265024 |
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| author | A. Käser M. Dieterle L. Witthauer S. Abt P. Achenbach P. Adlarson F. Afzal Z. Ahmed J. Ahrens J.R.M. Annand H.J. Arends M. Bashkanov R. Beck M. Biroth N.S. Borisov A. Braghieri W.J. Briscoe F. Cividini C. Collicott S. Costanza A. Denig E.J. Downie P. Drexler A. Fix S. Garni D.I. Glazier I. Gorodnov W. Gradl M. Günther G.M. Gurevich L. Heijkenskjöld D. Hornidge G.M. Huber V.L. Kashevarov S. Kay I. Keshelashvili R. Kondratiev M. Korolija B. Krusche A.B. Lazarev V. Lisin K. Livingston S. Lutterer I.J.D. MacGregor D.M. Manley P.P. Martel V. Metag W. Meyer R. Miskimen E. Mornacchi A. Mushkarenkov A.B. Neganov A. Neiser M. Oberle M. Ostrick P.B. Otte D. Paudyal P. Pedroni A. Polonski S.N. Prakhov G. Reicherz G. Ron T. Rostomyan A. Sarty C. Sfienti V. Sokhoyan K. Spieker O. Steffen I.I. Strakovsky Th. Strub I. Supek A. Thiel M. Thiel A. Thomas M. Unverzagt Yu.A. Usov S. Wagner N.K. Walford D.P. Watts D. Werthmüller J. Wettig M. Wolfes L. Zana |
| author_facet | A. Käser M. Dieterle L. Witthauer S. Abt P. Achenbach P. Adlarson F. Afzal Z. Ahmed J. Ahrens J.R.M. Annand H.J. Arends M. Bashkanov R. Beck M. Biroth N.S. Borisov A. Braghieri W.J. Briscoe F. Cividini C. Collicott S. Costanza A. Denig E.J. Downie P. Drexler A. Fix S. Garni D.I. Glazier I. Gorodnov W. Gradl M. Günther G.M. Gurevich L. Heijkenskjöld D. Hornidge G.M. Huber V.L. Kashevarov S. Kay I. Keshelashvili R. Kondratiev M. Korolija B. Krusche A.B. Lazarev V. Lisin K. Livingston S. Lutterer I.J.D. MacGregor D.M. Manley P.P. Martel V. Metag W. Meyer R. Miskimen E. Mornacchi A. Mushkarenkov A.B. Neganov A. Neiser M. Oberle M. Ostrick P.B. Otte D. Paudyal P. Pedroni A. Polonski S.N. Prakhov G. Reicherz G. Ron T. Rostomyan A. Sarty C. Sfienti V. Sokhoyan K. Spieker O. Steffen I.I. Strakovsky Th. Strub I. Supek A. Thiel M. Thiel A. Thomas M. Unverzagt Yu.A. Usov S. Wagner N.K. Walford D.P. Watts D. Werthmüller J. Wettig M. Wolfes L. Zana |
| author_sort | A. Käser |
| collection | DOAJ |
| description | The helicity-dependent cross sections for the photoproduction of π0η pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball – TAPS calorimeter. The experiment used a polarized deuterated butanol target and a circularly polarized photon beam. This arrangement allowed the σ1/2 (photon and target spin antiparallel) and σ3/2 (parallel spins) components to be measured for quasi-free production of π0η pairs off protons and neutrons. The main finding is that the two helicity components contribute identically, within uncertainties, for both participant protons and neutrons. The absolute couplings for protons and neutrons are also identical. This means that nucleon resonances contributing to this reaction in the investigated energy range have almost equal electromagnetic helicity couplings, A1/2n,p and A3/2n,p. Identical couplings for protons and neutrons are typical for Δ resonances and identical A1/2 and A3/2 components are only possible for J≥3/2 states, which constrains possible contributions of nucleon resonances. |
| first_indexed | 2024-04-12T17:56:37Z |
| format | Article |
| id | doaj.art-717f46d2ce69489da1dbd0fd88849f11 |
| institution | Directory Open Access Journal |
| issn | 0370-2693 |
| language | English |
| last_indexed | 2024-04-12T17:56:37Z |
| publishDate | 2018-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Physics Letters B |
| spelling | doaj.art-717f46d2ce69489da1dbd0fd88849f112022-12-22T03:22:20ZengElsevierPhysics Letters B0370-26932018-11-01786305312First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleonsA. Käser0M. Dieterle1L. Witthauer2S. Abt3P. Achenbach4P. Adlarson5F. Afzal6Z. Ahmed7J. Ahrens8J.R.M. Annand9H.J. Arends10M. Bashkanov11R. Beck12M. Biroth13N.S. Borisov14A. Braghieri15W.J. Briscoe16F. Cividini17C. Collicott18S. Costanza19A. Denig20E.J. Downie21P. Drexler22A. Fix23S. Garni24D.I. Glazier25I. Gorodnov26W. Gradl27M. Günther28G.M. Gurevich29L. Heijkenskjöld30D. Hornidge31G.M. Huber32V.L. Kashevarov33S. Kay34I. Keshelashvili35R. Kondratiev36M. Korolija37B. Krusche38A.B. Lazarev39V. Lisin40K. Livingston41S. Lutterer42I.J.D. MacGregor43D.M. Manley44P.P. Martel45V. Metag46W. Meyer47R. Miskimen48E. Mornacchi49A. Mushkarenkov50A.B. Neganov51A. Neiser52M. Oberle53M. Ostrick54P.B. Otte55D. Paudyal56P. Pedroni57A. Polonski58S.N. Prakhov59G. Reicherz60G. Ron61T. Rostomyan62A. Sarty63C. Sfienti64V. Sokhoyan65K. Spieker66O. Steffen67I.I. Strakovsky68Th. Strub69I. Supek70A. Thiel71M. Thiel72A. Thomas73M. Unverzagt74Yu.A. Usov75S. Wagner76N.K. Walford77D.P. Watts78D. Werthmüller79J. Wettig80M. Wolfes81L. Zana82Department of Physics, University of Basel, Basel, SwitzerlandDepartment of Physics, University of Basel, Basel, SwitzerlandDepartment of Physics, University of Basel, Basel, SwitzerlandDepartment of Physics, University of Basel, Basel, SwitzerlandInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyHelmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, GermanyUniversity of Regina, Regina, SK S4S 0A2, CanadaInstitut für Kernphysik, University of Mainz, Mainz, GermanySUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UKInstitut für Kernphysik, University of Mainz, Mainz, GermanySUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UKHelmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyJoint Institute for Nuclear Research, 141980 Dubna, RussiaINFN Sezione di Pavia, Pavia, ItalyCenter for Nuclear Studies, The George Washington University, Washington, DC, USAInstitut für Kernphysik, University of Mainz, Mainz, GermanyDepartment of Astronomy and Physics, Saint Marys University, Halifax, CanadaINFN Sezione di Pavia, Pavia, ItalyInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, Germany; Center for Nuclear Studies, The George Washington University, Washington, DC, USAInstitut für Kernphysik, University of Mainz, Mainz, GermanyLaboratory of Mathematical Physics, Tomsk Polytechnic University, Tomsk, RussiaDepartment of Physics, University of Basel, Basel, SwitzerlandSUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UKJoint Institute for Nuclear Research, 141980 Dubna, RussiaInstitut für Kernphysik, University of Mainz, Mainz, GermanyDepartment of Physics, University of Basel, Basel, SwitzerlandInstitute for Nuclear Research, Moscow, RussiaInstitut für Kernphysik, University of Mainz, Mainz, GermanyMount Allison University, Sackville, New Brunswick E4L 1E6, CanadaUniversity of Regina, Regina, SK S4S 0A2, CanadaInstitut für Kernphysik, University of Mainz, Mainz, Germany; Joint Institute for Nuclear Research, 141980 Dubna, RussiaSUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UKDepartment of Physics, University of Basel, Basel, SwitzerlandInstitute for Nuclear Research, Moscow, RussiaRudjer Boskovic Institute, Zagreb, CroatiaDepartment of Physics, University of Basel, Basel, Switzerland; Corresponding author.Joint Institute for Nuclear Research, 141980 Dubna, RussiaInstitute for Nuclear Research, Moscow, RussiaSUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UKDepartment of Physics, University of Basel, Basel, SwitzerlandSUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UKKent State University, Kent, OH, USAInstitut für Kernphysik, University of Mainz, Mainz, Germany; Mount Allison University, Sackville, New Brunswick E4L 1E6, CanadaII. Physikalisches Institut, University of Giessen, GermanyInstitut für Experimentalphysik, Ruhr Universität, 44780 Bochum, GermanyUniversity of Massachusetts Amherst, Amherst, MA 01003, USAInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitute for Nuclear Research, Moscow, Russia; University of Massachusetts Amherst, Amherst, MA 01003, USAJoint Institute for Nuclear Research, 141980 Dubna, RussiaInstitut für Kernphysik, University of Mainz, Mainz, GermanyDepartment of Physics, University of Basel, Basel, SwitzerlandInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyUniversity of Regina, Regina, SK S4S 0A2, CanadaINFN Sezione di Pavia, Pavia, ItalyInstitute for Nuclear Research, Moscow, RussiaInstitut für Kernphysik, University of Mainz, Mainz, Germany; University of California at Los Angeles, Los Angeles, CA, USAInstitut für Experimentalphysik, Ruhr Universität, 44780 Bochum, GermanyRacah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, IsraelDepartment of Physics, University of Basel, Basel, SwitzerlandDepartment of Astronomy and Physics, Saint Marys University, Halifax, CanadaInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, Germany; Center for Nuclear Studies, The George Washington University, Washington, DC, USAHelmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyCenter for Nuclear Studies, The George Washington University, Washington, DC, USADepartment of Physics, University of Basel, Basel, SwitzerlandRudjer Boskovic Institute, Zagreb, CroatiaHelmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanyJoint Institute for Nuclear Research, 141980 Dubna, RussiaInstitut für Kernphysik, University of Mainz, Mainz, GermanyDepartment of Physics, University of Basel, Basel, SwitzerlandSUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UKDepartment of Physics, University of Basel, Basel, Switzerland; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UKInstitut für Kernphysik, University of Mainz, Mainz, GermanyInstitut für Kernphysik, University of Mainz, Mainz, GermanySUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UKThe helicity-dependent cross sections for the photoproduction of π0η pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball – TAPS calorimeter. The experiment used a polarized deuterated butanol target and a circularly polarized photon beam. This arrangement allowed the σ1/2 (photon and target spin antiparallel) and σ3/2 (parallel spins) components to be measured for quasi-free production of π0η pairs off protons and neutrons. The main finding is that the two helicity components contribute identically, within uncertainties, for both participant protons and neutrons. The absolute couplings for protons and neutrons are also identical. This means that nucleon resonances contributing to this reaction in the investigated energy range have almost equal electromagnetic helicity couplings, A1/2n,p and A3/2n,p. Identical couplings for protons and neutrons are typical for Δ resonances and identical A1/2 and A3/2 components are only possible for J≥3/2 states, which constrains possible contributions of nucleon resonances.http://www.sciencedirect.com/science/article/pii/S0370269318307639 |
| spellingShingle | A. Käser M. Dieterle L. Witthauer S. Abt P. Achenbach P. Adlarson F. Afzal Z. Ahmed J. Ahrens J.R.M. Annand H.J. Arends M. Bashkanov R. Beck M. Biroth N.S. Borisov A. Braghieri W.J. Briscoe F. Cividini C. Collicott S. Costanza A. Denig E.J. Downie P. Drexler A. Fix S. Garni D.I. Glazier I. Gorodnov W. Gradl M. Günther G.M. Gurevich L. Heijkenskjöld D. Hornidge G.M. Huber V.L. Kashevarov S. Kay I. Keshelashvili R. Kondratiev M. Korolija B. Krusche A.B. Lazarev V. Lisin K. Livingston S. Lutterer I.J.D. MacGregor D.M. Manley P.P. Martel V. Metag W. Meyer R. Miskimen E. Mornacchi A. Mushkarenkov A.B. Neganov A. Neiser M. Oberle M. Ostrick P.B. Otte D. Paudyal P. Pedroni A. Polonski S.N. Prakhov G. Reicherz G. Ron T. Rostomyan A. Sarty C. Sfienti V. Sokhoyan K. Spieker O. Steffen I.I. Strakovsky Th. Strub I. Supek A. Thiel M. Thiel A. Thomas M. Unverzagt Yu.A. Usov S. Wagner N.K. Walford D.P. Watts D. Werthmüller J. Wettig M. Wolfes L. Zana First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons Physics Letters B |
| title | First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons |
| title_full | First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons |
| title_fullStr | First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons |
| title_full_unstemmed | First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons |
| title_short | First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons |
| title_sort | first measurement of helicity dependent cross sections in π0η photoproduction from quasi free nucleons |
| url | http://www.sciencedirect.com/science/article/pii/S0370269318307639 |
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