Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of φ0φ± pairs off protons and off neutrons

M. Oberle; J. Ahrens; J. R.M. Annand; H. J. Arends; K. Bantawa; P. A. Bartolome; R. Beck; V. Bekrenev; H. Berghäuser; A. Braghieri; D. Branford; W. J. Briscoe; J. Brudvik; S. Cherepnya; B. Demissie; M. Dieterle; E. J. Downie; P. Drexler; L. V. Fil'kov; A. Fix; D. I. Glazier; E. Heid; D. Hornidge; D. Howdle; G. M. Huber; O. Jahn; I. Jaegle; T. C. Jude; A. Käser; V. L. Kashevarov; I. Keshelashvili; R. Kondratiev; M. Korolija; S. P. Kruglov; B. Krusche; A. Kulbardis; V. Lisin; K. Livingston; I. J.D. MacGregor; Y. Maghrbi; J. Mancell; D. M. Manley; Z. Marinides; M. Martinez; J. C. McGeorge; E. McNicoll; D. Mekterovic; V. Metag; S. Micanovic; D. G. Middleton; A. Mushkarenkov; B. M.K. Nefkens; A. Nikolaev; R. Novotny; M. Ostrick; B. Oussena; P. Pedroni; F. Pheron; A. Polonski; S. N. Prakhov; G. Rosner; T. Rostomyan; S. Schumann; M. H. Sikora; D. I. Sober; A. Starostin; I. Supek; M. Thiel; M. Unverzagt; D. P. Watts; D. Werthmüller; L. Witthauer; F. Zehr

doi:10.1140/epja/i2014-14054-5

Measurement of the beam-helicity asymmetry I^⊙ in the photoproduction of φ⁰φ^± pairs off protons and off neutrons

M. Oberle, J. Ahrens, J. R.M. Annand, H. J. Arends, K. Bantawa, P. A. Bartolome, R. Beck, V. Bekrenev, H. Berghäuser, A. Braghieri, D. Branford, W. J. Briscoe, J. Brudvik, S. Cherepnya, B. Demissie, M. Dieterle, E. J. Downie, P. Drexler, L. V. Fil'kov, A. FixD. I. Glazier, E. Heid, D. Hornidge, D. Howdle, G. M. Huber, O. Jahn, I. Jaegle, T. C. Jude, A. Käser, V. L. Kashevarov, I. Keshelashvili, R. Kondratiev, M. Korolija, S. P. Kruglov, B. Krusche^*, A. Kulbardis, V. Lisin, K. Livingston, I. J.D. MacGregor, Y. Maghrbi, J. Mancell, D. M. Manley, Z. Marinides, M. Martinez, J. C. McGeorge, E. McNicoll, D. Mekterovic, V. Metag, S. Micanovic, D. G. Middleton, A. Mushkarenkov, B. M.K. Nefkens, A. Nikolaev, R. Novotny, M. Ostrick, B. Oussena, P. Pedroni, F. Pheron, A. Polonski, S. N. Prakhov, G. Rosner, T. Rostomyan, S. Schumann, M. H. Sikora, D. I. Sober, A. Starostin, I. Supek, M. Thiel, M. Unverzagt, D. P. Watts, D. Werthmüller, L. Witthauer, F. Zehr

^*Corresponding author for this work

Physics

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

Abstract

Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions -γp → nπ⁰π⁺ off free protons and γd → (p)pπ⁰π^- and γd → (n)nπ⁰π⁺ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from π ⁰ mesons were detected in the 4π electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region.

Original language	English
Article number	54
Number of pages	18
Journal	European Physical Journal A
Volume	50
Issue number	3
DOIs	https://doi.org/10.1140/epja/i2014-14054-5
Publication status	Published - Mar 2014

Access to Document

10.1140/epja/i2014-14054-5

Cite this

Oberle, M., Ahrens, J., Annand, J. R. M., Arends, H. J., Bantawa, K., Bartolome, P. A., Beck, R., Bekrenev, V., Berghäuser, H., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Demissie, B., Dieterle, M., Downie, E. J., Drexler, P., Fil'kov, L. V., ... Zehr, F. (2014). Measurement of the beam-helicity asymmetry I^⊙ in the photoproduction of φ⁰φ^± pairs off protons and off neutrons. European Physical Journal A, 50(3), Article 54. https://doi.org/10.1140/epja/i2014-14054-5

@article{3553947debe848aabf0c2d2b5918f114,

title = "Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of φ0φ± pairs off protons and off neutrons",

abstract = "Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions -γp → nπ0π+ off free protons and γd → (p)pπ0π- and γd → (n)nπ0π+ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from π 0 mesons were detected in the 4π electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region.",

author = "M. Oberle and J. Ahrens and Annand, {J. R.M.} and Arends, {H. J.} and K. Bantawa and Bartolome, {P. A.} and R. Beck and V. Bekrenev and H. Bergh{\"a}user and A. Braghieri and D. Branford and Briscoe, {W. J.} and J. Brudvik and S. Cherepnya and B. Demissie and M. Dieterle and Downie, {E. J.} and P. Drexler and Fil'kov, {L. V.} and A. Fix and Glazier, {D. I.} and E. Heid and D. Hornidge and D. Howdle and Huber, {G. M.} and O. Jahn and I. Jaegle and Jude, {T. C.} and A. K{\"a}ser and Kashevarov, {V. L.} and I. Keshelashvili and R. Kondratiev and M. Korolija and Kruglov, {S. P.} and B. Krusche and A. Kulbardis and V. Lisin and K. Livingston and MacGregor, {I. J.D.} and Y. Maghrbi and J. Mancell and Manley, {D. M.} and Z. Marinides and M. Martinez and McGeorge, {J. C.} and E. McNicoll and D. Mekterovic and V. Metag and S. Micanovic and Middleton, {D. G.} and A. Mushkarenkov and Nefkens, {B. M.K.} and A. Nikolaev and R. Novotny and M. Ostrick and B. Oussena and P. Pedroni and F. Pheron and A. Polonski and Prakhov, {S. N.} and G. Rosner and T. Rostomyan and S. Schumann and Sikora, {M. H.} and Sober, {D. I.} and A. Starostin and I. Supek and M. Thiel and M. Unverzagt and Watts, {D. P.} and D. Werthm{\"u}ller and L. Witthauer and F. Zehr",

year = "2014",

month = mar,

doi = "10.1140/epja/i2014-14054-5",

language = "English",

volume = "50",

journal = "European Physical Journal A",

issn = "1434-6001",

publisher = "Springer",

number = "3",

}

Oberle, M, Ahrens, J, Annand, JRM, Arends, HJ, Bantawa, K, Bartolome, PA, Beck, R, Bekrenev, V, Berghäuser, H, Braghieri, A, Branford, D, Briscoe, WJ, Brudvik, J, Cherepnya, S, Demissie, B, Dieterle, M, Downie, EJ, Drexler, P, Fil'kov, LV, Fix, A, Glazier, DI, Heid, E, Hornidge, D, Howdle, D, Huber, GM, Jahn, O, Jaegle, I, Jude, TC, Käser, A, Kashevarov, VL, Keshelashvili, I, Kondratiev, R, Korolija, M, Kruglov, SP, Krusche, B, Kulbardis, A, Lisin, V, Livingston, K, MacGregor, IJD, Maghrbi, Y, Mancell, J, Manley, DM, Marinides, Z, Martinez, M, McGeorge, JC, McNicoll, E, Mekterovic, D, Metag, V, Micanovic, S, Middleton, DG, Mushkarenkov, A, Nefkens, BMK, Nikolaev, A, Novotny, R, Ostrick, M, Oussena, B, Pedroni, P, Pheron, F, Polonski, A, Prakhov, SN, Rosner, G, Rostomyan, T, Schumann, S, Sikora, MH, Sober, DI, Starostin, A, Supek, I, Thiel, M, Unverzagt, M, Watts, DP , Werthmüller, D, Witthauer, L & Zehr, F 2014, 'Measurement of the beam-helicity asymmetry I^⊙ in the photoproduction of φ⁰φ^± pairs off protons and off neutrons', European Physical Journal A, vol. 50, no. 3, 54. https://doi.org/10.1140/epja/i2014-14054-5

TY - JOUR

T1 - Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of φ0φ± pairs off protons and off neutrons

AU - Oberle, M.

AU - Ahrens, J.

AU - Annand, J. R.M.

AU - Arends, H. J.

AU - Bantawa, K.

AU - Bartolome, P. A.

AU - Beck, R.

AU - Bekrenev, V.

AU - Berghäuser, H.

AU - Braghieri, A.

AU - Branford, D.

AU - Briscoe, W. J.

AU - Brudvik, J.

AU - Cherepnya, S.

AU - Demissie, B.

AU - Dieterle, M.

AU - Downie, E. J.

AU - Drexler, P.

AU - Fil'kov, L. V.

AU - Fix, A.

AU - Glazier, D. I.

AU - Heid, E.

AU - Hornidge, D.

AU - Howdle, D.

AU - Huber, G. M.

AU - Jahn, O.

AU - Jaegle, I.

AU - Jude, T. C.

AU - Käser, A.

AU - Kashevarov, V. L.

AU - Keshelashvili, I.

AU - Kondratiev, R.

AU - Korolija, M.

AU - Kruglov, S. P.

AU - Krusche, B.

AU - Kulbardis, A.

AU - Lisin, V.

AU - Livingston, K.

AU - MacGregor, I. J.D.

AU - Maghrbi, Y.

AU - Mancell, J.

AU - Manley, D. M.

AU - Marinides, Z.

AU - Martinez, M.

AU - McGeorge, J. C.

AU - McNicoll, E.

AU - Mekterovic, D.

AU - Metag, V.

AU - Micanovic, S.

AU - Middleton, D. G.

AU - Mushkarenkov, A.

AU - Nefkens, B. M.K.

AU - Nikolaev, A.

AU - Novotny, R.

AU - Ostrick, M.

AU - Oussena, B.

AU - Pedroni, P.

AU - Pheron, F.

AU - Polonski, A.

AU - Prakhov, S. N.

AU - Rosner, G.

AU - Rostomyan, T.

AU - Schumann, S.

AU - Sikora, M. H.

AU - Sober, D. I.

AU - Starostin, A.

AU - Supek, I.

AU - Thiel, M.

AU - Unverzagt, M.

AU - Watts, D. P.

AU - Werthmüller, D.

AU - Witthauer, L.

AU - Zehr, F.

PY - 2014/3

Y1 - 2014/3

N2 - Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions -γp → nπ0π+ off free protons and γd → (p)pπ0π- and γd → (n)nπ0π+ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from π 0 mesons were detected in the 4π electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region.

AB - Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions -γp → nπ0π+ off free protons and γd → (p)pπ0π- and γd → (n)nπ0π+ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from π 0 mesons were detected in the 4π electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region.

UR - http://www.scopus.com/inward/record.url?scp=84899623132&partnerID=8YFLogxK

U2 - 10.1140/epja/i2014-14054-5

DO - 10.1140/epja/i2014-14054-5

M3 - Article

AN - SCOPUS:84899623132

SN - 1434-6001

VL - 50

JO - European Physical Journal A

JF - European Physical Journal A

IS - 3

M1 - 54

ER -

Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of φ0φ± pairs off protons and off neutrons

Abstract

Access to Document

Other files and links

Cite this

Measurement of the beam-helicity asymmetry I^⊙ in the photoproduction of φ⁰φ^± pairs off protons and off neutrons