Quasi-free photoproduction of eta-mesons off He-3 nuclei

L. Witthauer; D. Werthmueller; I. Keshelashvili; P. Aguar-Bartolome; J. Ahrens; J. R. M. Annand; H. J. Arends; K. Bantawa; R. Beck; V. Bekrenev; 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; D. Hamilton; E. Heid; D. Hornidge; D. Howdle; G. M. Huber; I. Jaegle; O. Jahn; T. C. Jude; A. Kaeser; V. L. Kashevarov; 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; V. Metag; D. G. Middleton; A. Mushkarenkov; B. M. K. Nefkens; A. Nikolaev; R. Novotny; M. Oberle; M. Ostrick; B. Oussena; P. Pedroni; F. Pheron; A. Polonski; S. Prakhov; J. Robinson; G. Rosner; M. Rost; T. Rostomyan; S. Schumann; M. H. Sikora; D. Sober; A. Starostin; I. Supek; M. Thiel; A. Thomas; M. Unverzagt; D. P. Watts

doi:10.1140/epja/i2013-13154-0

Quasi-free photoproduction of eta-mesons off He-3 nuclei

L. Witthauer^*, D. Werthmueller, I. Keshelashvili, P. Aguar-Bartolome, J. Ahrens, J. R. M. Annand, H. J. Arends, K. Bantawa, R. Beck, V. Bekrenev, A. Braghieri, D. Branford, W. J. Briscoe, J. Brudvik, S. Cherepnya, B. Demissie, M. Dieterle, E. J. Downie, P. Drexler, L. V. Fil'kovA. Fix, D. I. Glazier, D. Hamilton, E. Heid, D. Hornidge, D. Howdle, G. M. Huber, I. Jaegle, O. Jahn, T. C. Jude, A. Kaeser, V. L. Kashevarov, 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, V. Metag, D. G. Middleton, A. Mushkarenkov, B. M. K. Nefkens, A. Nikolaev, R. Novotny, M. Oberle, M. Ostrick, B. Oussena, P. Pedroni, F. Pheron, A. Polonski, S. Prakhov, J. Robinson, G. Rosner, M. Rost, T. Rostomyan, S. Schumann, M. H. Sikora, D. Sober, A. Starostin, I. Supek, M. Thiel, A. Thomas, M. Unverzagt, D. P. Watts

^*Corresponding author for this work

School of Physics and Astronomy

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

Abstract / Description of output

Quasi-free photoproduction of eta-mesons has been measured off nucleons bound in He-3 nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4 pi covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The eta-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S-11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects.

Original language	English
Article number	154
Number of pages	18
Journal	The European Physical Journal A (EPJ A)
Volume	49
Issue number	12
DOIs	https://doi.org/10.1140/epja/i2013-13154-0
Publication status	Published - 16 Dec 2013

Keywords / Materials (for Non-textual outputs)

NEAR-THRESHOLD PHOTOPRODUCTION
TAGGED PHOTON SPECTROMETER
COHERENT PHOTOPRODUCTION
PI(0) PHOTOPRODUCTION
EXCLUSIVE MEASUREMENT
BEAM ASYMMETRY
PROTON
DEUTERON
RESONANCE
MICROTRON

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10.1140/epja/i2013-13154-0

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Witthauer, L., Werthmueller, D., Keshelashvili, I., Aguar-Bartolome, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Bantawa, K., Beck, R., Bekrenev, V., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Demissie, B., Dieterle, M., Downie, E. J., Drexler, P., ... Watts, D. P. (2013). Quasi-free photoproduction of eta-mesons off He-3 nuclei. The European Physical Journal A (EPJ A), 49(12), Article 154. https://doi.org/10.1140/epja/i2013-13154-0

@article{d84c503fd1ff4da4af8802d581c05ac8,

title = "Quasi-free photoproduction of eta-mesons off He-3 nuclei",

abstract = "Quasi-free photoproduction of eta-mesons has been measured off nucleons bound in He-3 nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4 pi covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The eta-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S-11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects.",

keywords = "NEAR-THRESHOLD PHOTOPRODUCTION, TAGGED PHOTON SPECTROMETER, COHERENT PHOTOPRODUCTION, PI(0) PHOTOPRODUCTION, EXCLUSIVE MEASUREMENT, BEAM ASYMMETRY, PROTON, DEUTERON, RESONANCE, MICROTRON",

author = "L. Witthauer and D. Werthmueller and I. Keshelashvili and P. Aguar-Bartolome and J. Ahrens and Annand, {J. R. M.} and Arends, {H. J.} and K. Bantawa and R. Beck and V. Bekrenev 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 D. Hamilton and E. Heid and D. Hornidge and D. Howdle and Huber, {G. M.} and I. Jaegle and O. Jahn and Jude, {T. C.} and A. Kaeser and Kashevarov, {V. L.} 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 V. Metag and Middleton, {D. G.} and A. Mushkarenkov and Nefkens, {B. M. K.} and A. Nikolaev and R. Novotny and M. Oberle and M. Ostrick and B. Oussena and P. Pedroni and F. Pheron and A. Polonski and S. Prakhov and J. Robinson and G. Rosner and M. Rost and T. Rostomyan and S. Schumann and Sikora, {M. H.} and D. Sober and A. Starostin and I. Supek and M. Thiel and A. Thomas and M. Unverzagt and Watts, {D. P.}",

year = "2013",

month = dec,

day = "16",

doi = "10.1140/epja/i2013-13154-0",

language = "English",

volume = "49",

journal = "The European Physical Journal A (EPJ A)",

issn = "1434-6001",

publisher = "Springer",

number = "12",

}

Witthauer, L, Werthmueller, D, Keshelashvili, I, Aguar-Bartolome, P, Ahrens, J, Annand, JRM, Arends, HJ, Bantawa, K, Beck, R, Bekrenev, V, 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, Hamilton, D, Heid, E, Hornidge, D, Howdle, D, Huber, GM, Jaegle, I, Jahn, O, Jude, TC, Kaeser, A, Kashevarov, VL, 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, Metag, V, Middleton, DG, Mushkarenkov, A, Nefkens, BMK, Nikolaev, A, Novotny, R, Oberle, M, Ostrick, M, Oussena, B, Pedroni, P, Pheron, F, Polonski, A, Prakhov, S, Robinson, J, Rosner, G, Rost, M, Rostomyan, T, Schumann, S, Sikora, MH, Sober, D, Starostin, A, Supek, I, Thiel, M, Thomas, A, Unverzagt, M & Watts, DP 2013, 'Quasi-free photoproduction of eta-mesons off He-3 nuclei', The European Physical Journal A (EPJ A), vol. 49, no. 12, 154. https://doi.org/10.1140/epja/i2013-13154-0

TY - JOUR

T1 - Quasi-free photoproduction of eta-mesons off He-3 nuclei

AU - Witthauer, L.

AU - Werthmueller, D.

AU - Keshelashvili, I.

AU - Aguar-Bartolome, P.

AU - Ahrens, J.

AU - Annand, J. R. M.

AU - Arends, H. J.

AU - Bantawa, K.

AU - Beck, R.

AU - Bekrenev, V.

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 - Hamilton, D.

AU - Heid, E.

AU - Hornidge, D.

AU - Howdle, D.

AU - Huber, G. M.

AU - Jaegle, I.

AU - Jahn, O.

AU - Jude, T. C.

AU - Kaeser, A.

AU - Kashevarov, V. L.

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 - Metag, V.

AU - Middleton, D. G.

AU - Mushkarenkov, A.

AU - Nefkens, B. M. K.

AU - Nikolaev, A.

AU - Novotny, R.

AU - Oberle, M.

AU - Ostrick, M.

AU - Oussena, B.

AU - Pedroni, P.

AU - Pheron, F.

AU - Polonski, A.

AU - Prakhov, S.

AU - Robinson, J.

AU - Rosner, G.

AU - Rost, M.

AU - Rostomyan, T.

AU - Schumann, S.

AU - Sikora, M. H.

AU - Sober, D.

AU - Starostin, A.

AU - Supek, I.

AU - Thiel, M.

AU - Thomas, A.

AU - Unverzagt, M.

AU - Watts, D. P.

PY - 2013/12/16

Y1 - 2013/12/16

N2 - Quasi-free photoproduction of eta-mesons has been measured off nucleons bound in He-3 nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4 pi covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The eta-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S-11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects.

AB - Quasi-free photoproduction of eta-mesons has been measured off nucleons bound in He-3 nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4 pi covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The eta-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S-11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects.

KW - NEAR-THRESHOLD PHOTOPRODUCTION

KW - TAGGED PHOTON SPECTROMETER

KW - COHERENT PHOTOPRODUCTION

KW - PI(0) PHOTOPRODUCTION

KW - EXCLUSIVE MEASUREMENT

KW - BEAM ASYMMETRY

KW - PROTON

KW - DEUTERON

KW - RESONANCE

KW - MICROTRON

U2 - 10.1140/epja/i2013-13154-0

DO - 10.1140/epja/i2013-13154-0

M3 - Article

SN - 1434-6001

VL - 49

JO - The European Physical Journal A (EPJ A)

JF - The European Physical Journal A (EPJ A)

IS - 12

M1 - 154

ER -

Quasi-free photoproduction of eta-mesons off He-3 nuclei

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Keywords / Materials (for Non-textual outputs)

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