Determination of quadrupole strengths in the γ* p → Δ (1232) transition at Q2 = 0.20 (GeV / c)2

N. F. Sparveris; P. Achenbach; C. Ayerbe Gayoso; D. Baumann; J. Bernauer; A. M. Bernstein; R. Böhm; D. Bosnar; T. Botto; A. Christopoulou; D. Dale; M. Ding; M. O. Distler; L. Doria; J. Friedrich; A. Karabarbounis; M. Makek; H. Merkel; U. Müller; I. Nakagawa; R. Neuhausen; L. Nungesser; C. N. Papanicolas; A. Piegsa; J. Pochodzalla; M. Potokar; M. Seimetz; S. Širca; S. Stave; S. Stiliaris; Th Walcher; M. Weis

doi:10.1016/j.physletb.2007.04.056

Determination of quadrupole strengths in the γ^* p → Δ (1232) transition at Q² = 0.20 (GeV / c)²

N. F. Sparveris
, P. Achenbach
, C. Ayerbe Gayoso
, D. Baumann
, J. Bernauer
, A. M. Bernstein
, R. Böhm
, D. Bosnar
, T. Botto
, A. Christopoulou
, D. Dale
, M. Ding
, M. O. Distler
, L. Doria
, J. Friedrich
, A. Karabarbounis
, M. Makek
, H. Merkel
, U. Müller
, I. Nakagawa

R. Neuhausen, L. Nungesser, C. N. Papanicolas, A. Piegsa, J. Pochodzalla, M. Potokar, M. Seimetz, S. Širca, S. Stave, S. Stiliaris, Th Walcher, M. Weis

Physics and Astronomy

National and Kapodistrian University of Athens
Johannes Gutenberg University Mainz
Massachusetts Institute of Technology
University of Zagreb
University of Kentucky
RIKEN
University of Ljubljana

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

46 Scopus citations

Abstract

We report new precise p (over(e, →), e^′ p) π⁰ measurements at the peak of the Δ⁺ (1232) resonance at Q² = 0.20 (GeV / c)² performed at the Mainz Microtron (MAMI). The new data are sensitive to both the electric (E2) and the Coulomb (C2) quadrupole amplitudes of the γ^* N → Δ transition. They yield precise quadrupole to dipole amplitude ratios: CMR = (- 5.09 ± 0.28_{stat + sys} ± 0.30_model) % and EMR = (- 1.96 ± 0.68_{stat + sys} ± 0.41_model) % for M_{1 +}^{3 / 2} = (39.57 ± 0.75_{stat + sys} ± 0.40_model) (10^-3 / m_π+). The new results are in disagreement with Constituent Quark Model predictions and in qualitative agreement with models that account for mesonic contributions, including recent Lattice calculations. They thus give further credence to the conjecture of deformation in hadronic systems favoring the attribution of the origin of deformation to the dominance of mesonic effects.

Original language	English
Pages (from-to)	102-107
Number of pages	6
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	651
Issue number	2-3
DOIs	https://doi.org/10.1016/j.physletb.2007.04.056
State	Published - Jul 26 2007

Keywords

CMR
Electro-pion production
EMR
Nucleon deformation

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10.1016/j.physletb.2007.04.056

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Sparveris, N. F., Achenbach, P., Gayoso, C. A., Baumann, D., Bernauer, J., Bernstein, A. M., Böhm, R., Bosnar, D., Botto, T., Christopoulou, A., Dale, D., Ding, M., Distler, M. O., Doria, L., Friedrich, J., Karabarbounis, A., Makek, M., Merkel, H., Müller, U., ... Weis, M. (2007). Determination of quadrupole strengths in the γ^* p → Δ (1232) transition at Q² = 0.20 (GeV / c)². Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 651(2-3), 102-107. https://doi.org/10.1016/j.physletb.2007.04.056

@article{85ad819385d242318893f3d566959b4f,

title = "Determination of quadrupole strengths in the γ* p → Δ (1232) transition at Q2 = 0.20 (GeV / c)2",

abstract = "We report new precise p (over(e, →), e′ p) π0 measurements at the peak of the Δ+ (1232) resonance at Q2 = 0.20 (GeV / c)2 performed at the Mainz Microtron (MAMI). The new data are sensitive to both the electric (E2) and the Coulomb (C2) quadrupole amplitudes of the γ* N → Δ transition. They yield precise quadrupole to dipole amplitude ratios: CMR = (- 5.09 ± 0.28stat + sys ± 0.30model) \% and EMR = (- 1.96 ± 0.68stat + sys ± 0.41model) \% for M1 +3 / 2 = (39.57 ± 0.75stat + sys ± 0.40model) (10-3 / mπ+). The new results are in disagreement with Constituent Quark Model predictions and in qualitative agreement with models that account for mesonic contributions, including recent Lattice calculations. They thus give further credence to the conjecture of deformation in hadronic systems favoring the attribution of the origin of deformation to the dominance of mesonic effects.",

keywords = "CMR, Electro-pion production, EMR, Nucleon deformation",

author = "Sparveris, \{N. F.\} and P. Achenbach and Gayoso, \{C. Ayerbe\} and D. Baumann and J. Bernauer and Bernstein, \{A. M.\} and R. B{\"o}hm and D. Bosnar and T. Botto and A. Christopoulou and D. Dale and M. Ding and Distler, \{M. O.\} and L. Doria and J. Friedrich and A. Karabarbounis and M. Makek and H. Merkel and U. M{\"u}ller and I. Nakagawa and R. Neuhausen and L. Nungesser and Papanicolas, \{C. N.\} and A. Piegsa and J. Pochodzalla and M. Potokar and M. Seimetz and S. {\v S}irca and S. Stave and S. Stiliaris and Th Walcher and M. Weis",

year = "2007",

month = jul,

day = "26",

doi = "10.1016/j.physletb.2007.04.056",

language = "English",

volume = "651",

pages = "102--107",

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

issn = "0370-2693",

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Sparveris, NF, Achenbach, P, Gayoso, CA, Baumann, D, Bernauer, J, Bernstein, AM, Böhm, R, Bosnar, D, Botto, T, Christopoulou, A, Dale, D, Ding, M, Distler, MO, Doria, L, Friedrich, J, Karabarbounis, A, Makek, M, Merkel, H, Müller, U, Nakagawa, I, Neuhausen, R, Nungesser, L, Papanicolas, CN, Piegsa, A, Pochodzalla, J, Potokar, M, Seimetz, M, Širca, S, Stave, S, Stiliaris, S, Walcher, T & Weis, M 2007, 'Determination of quadrupole strengths in the γ^* p → Δ (1232) transition at Q² = 0.20 (GeV / c)²', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 651, no. 2-3, pp. 102-107. https://doi.org/10.1016/j.physletb.2007.04.056

TY - JOUR

T1 - Determination of quadrupole strengths in the γ* p → Δ (1232) transition at Q2 = 0.20 (GeV / c)2

AU - Sparveris, N. F.

AU - Achenbach, P.

AU - Gayoso, C. Ayerbe

AU - Baumann, D.

AU - Bernauer, J.

AU - Bernstein, A. M.

AU - Böhm, R.

AU - Bosnar, D.

AU - Botto, T.

AU - Christopoulou, A.

AU - Dale, D.

AU - Ding, M.

AU - Distler, M. O.

AU - Doria, L.

AU - Friedrich, J.

AU - Karabarbounis, A.

AU - Makek, M.

AU - Merkel, H.

AU - Müller, U.

AU - Nakagawa, I.

AU - Neuhausen, R.

AU - Nungesser, L.

AU - Papanicolas, C. N.

AU - Piegsa, A.

AU - Pochodzalla, J.

AU - Potokar, M.

AU - Seimetz, M.

AU - Širca, S.

AU - Stave, S.

AU - Stiliaris, S.

AU - Walcher, Th

AU - Weis, M.

PY - 2007/7/26

Y1 - 2007/7/26

N2 - We report new precise p (over(e, →), e′ p) π0 measurements at the peak of the Δ+ (1232) resonance at Q2 = 0.20 (GeV / c)2 performed at the Mainz Microtron (MAMI). The new data are sensitive to both the electric (E2) and the Coulomb (C2) quadrupole amplitudes of the γ* N → Δ transition. They yield precise quadrupole to dipole amplitude ratios: CMR = (- 5.09 ± 0.28stat + sys ± 0.30model) % and EMR = (- 1.96 ± 0.68stat + sys ± 0.41model) % for M1 +3 / 2 = (39.57 ± 0.75stat + sys ± 0.40model) (10-3 / mπ+). The new results are in disagreement with Constituent Quark Model predictions and in qualitative agreement with models that account for mesonic contributions, including recent Lattice calculations. They thus give further credence to the conjecture of deformation in hadronic systems favoring the attribution of the origin of deformation to the dominance of mesonic effects.

AB - We report new precise p (over(e, →), e′ p) π0 measurements at the peak of the Δ+ (1232) resonance at Q2 = 0.20 (GeV / c)2 performed at the Mainz Microtron (MAMI). The new data are sensitive to both the electric (E2) and the Coulomb (C2) quadrupole amplitudes of the γ* N → Δ transition. They yield precise quadrupole to dipole amplitude ratios: CMR = (- 5.09 ± 0.28stat + sys ± 0.30model) % and EMR = (- 1.96 ± 0.68stat + sys ± 0.41model) % for M1 +3 / 2 = (39.57 ± 0.75stat + sys ± 0.40model) (10-3 / mπ+). The new results are in disagreement with Constituent Quark Model predictions and in qualitative agreement with models that account for mesonic contributions, including recent Lattice calculations. They thus give further credence to the conjecture of deformation in hadronic systems favoring the attribution of the origin of deformation to the dominance of mesonic effects.

KW - CMR

KW - Electro-pion production

KW - EMR

KW - Nucleon deformation

UR - https://www.scopus.com/pages/publications/34447269943

U2 - 10.1016/j.physletb.2007.04.056

DO - 10.1016/j.physletb.2007.04.056

M3 - Article

AN - SCOPUS:34447269943

SN - 0370-2693

VL - 651

SP - 102

EP - 107

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

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

IS - 2-3

ER -

Determination of quadrupole strengths in the γ^* p → Δ (1232) transition at Q² = 0.20 (GeV / c)²

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Keywords

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