A1. Spektroskopie von Baryonen-Resonanzen

R. Beck, U.Thoma

Das Ziel dieses Projektes ist es, ein detailliertes Verständnis des Spektrums und der Eigenschaften von Baryon-Resonanzen, den Bindungszuständen der starken Wechselwirkung zu gewinnen. Mit dem Crystal Barrel / TAPS Experiment an ELSA wird hierfür die Photoproduktion von Einfach- und Multi-Meson-Endzuständen am Proton und am Neutron untersucht. Einfach- und Doppelpolarisations-experimente mit zirkular oder linear polarisiertem Photonenstrahl und longitudinal oder transversal polarisiertem Target machen hierbei Polarisationsobservablen zugänglich, die für die Extraktion der Resonanzen aus den Daten von entscheidender Bedeutung sind.

Publikationen

Veröffentlichte und akzeptierte Beiträge

A. Thiel et al. [CBELSA/TAPS Collaboration]

„Double-polarization observable G in neutral-pion photoproduction off the proton″,
[arXiv:1604.02922 [nucl-ex]].

A. Wilson et al. [CBELSA/TAPS Collaboration]

„Photoproduction of ω mesons off the proton″,
Phys. Lett. B 749 (2015) 407, [arXiv:1508.01483 [nucl-ex]].

V. Sokhoyan et al. [CBELSA/TAPS Collaboration]

„High-statistics study of the reaction γ p → p 2π⁰″,
Eur. Phys. J. A 51 (2015) no.8, 95 , Erratum: Eur. Phys. J. A 51 (2015) no.12, 187, [arXiv:1507.02488 [nucl-ex]].

J. Hartmann et al. [CBELSA/TAPS Collaboration]

„The polarization observables T , P , and H and their impact on γ p → p π⁰ multipoles″,
Phys. Lett. B 748 (2015) 212, [arXiv:1506.06226 [nucl-ex]].

V. Sokhoyan et al. [CBELSA/TAPS Collaboration]

„Data on I^s and I^c in γ p → p π⁰ π⁰ reveal cascade decays of N(1900) via N(1520)π″,
Phys. Lett. B 746 (2015) 127

A. Thiel et al. [CBELSA/TAPS Collaboration]

„Three-body nature of N^* and Δ^* resonances from sequential decay chains″,
Phys. Rev. Lett. 114 (2015) no.9, 091803, [arXiv:1501.02094 [nucl-ex]].

J. Hartmann et al. [CBELSA/TAPS Collaboration]

„The N(1520) 3/2- helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions″,
Phys. Rev. Lett. 113 (2014) 062001, [arXiv:1407.2163 [nucl-ex]].

E. Gutz et al. [CBELSA/TAPS Collaboration]

„High statistics study of the reaction γp → pπ⁰η″,
Eur. Phys. J. A 50 (2014) 74, [arXiv:1402.4125 [nucl-ex]].

M. Gottschall et al. [CBELSA/TAPS Collaboration]

„First measurement of the helicity asymmetry for γp → pπ⁰ in the resonance region″,
Phys. Rev. Lett. 112 (2014) 012003, [arXiv:1312.2187 [nucl-ex]].

A. Thiel et al. [CBELSA/TAPS Collaboration]

„Well-established nucleon reconances revisited by double-polarization measurements″,
Phys. Rev. Lett. 109(2012) 102001, [arXiv:1207.2686 [nucl-ex]].

V. Crede et al. [CBELSA/TAPS Collaboration]

„Photoproduction of Neutral Pions off Protons″,
Phys. Rev. C 84 (2011) 055203, [arXiv:1107.2151 [nucl-ex]].

I. Jaegle et al. [CBELSA/TAPS Collaboration]

„Quasi-free photoproduction of η-mesons off the deuteron″,
Eur. Phys. J. A 47 (2011) 89, [arXiv:1107.2046 [nucl-ex]].

I. Jaegle et al. [CBELSA/TAPS Collaboration]

„Photoproduction of η′-mesons off the deuteron″,
Eur. Phys. J. A 47 (2011) 11, [arXiv:1012.1021 [nucl-ex]].

E. Gutz et al. [CBELSA/TAPS Collaboration]

„Photoproduction of meson pairs: First measurement of the polarization observable I^s″,
Phys. Lett. B 687 (2010) 11, [arXiv:0912.2632 [nucl-ex]].

N. Sparks et al. [CBELSA/TAPS Collaboration]

„Measurement of the Beam Asymmetry Σ in the Forward Direction for γ→p → pπ⁰ Photoproduction″,
Phys. Rev. C 81 (2010) 065210, [arXiv:1003.1346 [nucl-ex]].

V. Crede et al. [CBELSA/TAPS Collaboration]

„Photoproduction of η and η′ mesons off protons″,
Phys. Rev. C 80 (2009) 055202, [arXiv:0909.1248 [nucl-ex]].

T. Mertens et al. [CBELSA/TAPS Collaboration]

„Photoproduction of η-mesons off nuclei for E_γ <= 2.2 GeV″,
Eur. Phys. J. A 38 (2008) 195, [arXiv:0810.2678 [nucl-ex]].

I. Horn et al. [CB-ELSA Collaboration]

„Study of the reaction γp → pπ⁰η″,
Eur. Phys. J. A 38 (2008) 173, [arXiv:0806.4251 [nucl-ex]].

M. Nanova et al. [CBELSA/TAPS Collaboration]

„K⁰ π⁰ Σ⁺ and K^*0Σ⁺ photoproduction off the proton″,
Eur. Phys. J. A 35 (2008) 333, [arXiv:0803.2146 [nucl-ex]].

E. Gutz et al. [CBELSA/TAPS Collaboration]

„Measurement of the beam asymmetry Σ in π⁰η production off the proton with the CBELSA/TAPS experiment″,
Eur. Phys. J. A 35 (2008) 291.

I. Horn et al. [CB-ELSA Collaboration]

„Evidence for a Parity Doublet Δ(1920)P₃₃ and Δ(1940)D₃₃ from γp → pπ⁰ η″,
Phys. Rev. Lett. 101 (2008) 202002, [arXiv:0711.1138 [nucl-ex]].

I. Jaegle et al. [CBELSA/TAPS Collaboration]

„Quasi-free photoproduction of η-mesons of the neutron″,
Phys. Rev. Lett. 100 (2008) 252002, [arXiv:0804.4841 [nucl-ex]].

A.V. Sarantsev, M. Fuchs, M. Kotulla, U. Thoma et al. [CB-ELSA and A2-TAPS Collaborations]

„New results on the Roper resonance and the P₁₁ partial wave″,
Phys. Lett. B 659 (2008) 94-100, [arXiv:0707.3591 [hep-ph]].

U. Thoma, M. Fuchs et al. [CB-ELSA Collaboration]

„N* and Δ* decays into Nπ⁰π⁰″,
Phys. Lett. B 659 (2008) 87-93, [arXiv:0707.3592 [hep-ph]].

O. Bartholomy, V. Crede et al. [CB-ELSA Collaboration]

„Photoproduction of η mesons off protons″,
Eur. Phys. J. A 33 (2007) 133.

J. Junkersfeld et al. [CB-ELSA Collaboration]

„Photoproduction of π⁰ω off protons for E_γ ≤ 3 GeV″,
Eur. Phys. J. A 31 (2007) 365, [arXiv:0704.0710 [nucl-ex]].

H. van Pee, O. Bartholomy, V. Crede et al. [CB-ELSA Collaboration]

„Photoproduction of π⁰-mesons off protons from the Δ(1232) region to E_γ = 3 GeV″,
Eur. Phys. J. A 31 (2007) 61, [arXiv:0704.1776 [nucl-ex]].

O. Bartholomy, V. Crede, H. van Pee et al. [CB-ELSA Collaboration]

„Neutral pion photoproduction off protons in the energy range 0.3 GeV < E_γ < 3 GeV″,
Phys. Rev. Lett. 94 (2005) 012003, [arXiv:hep-ex/0407022].

V. Crede, O. Bartholomy et al. [CB-ELSA Collaboration]

„Photoproduction of η mesons off protons for 0.75 GeV < E_γ < 3 GeV″,
Phys. Rev. Lett. 94 (2005) 012004, [arXiv:hep-ex/0311045].

Verwandte Übersichtsartikel

E. Klempt, J.-M. Richard, and U. Thoma

„Baryon spectroscopy″,
Review commissioned for Rev. Mod. Phys. (2008).,

Sonstige relevante Veröffentlichungen

D.P. Watts, J.R.M. Annand, R. Beck, D. Branford, D. Glazier, P. Grabmayr, K. Livingston, I.J.D. MacGregor, J.C. McGeorge, R.O. Owens (A2 Collaboration)

„Dependence of the ¹²C(γ,pd) reaction on photon linear polarisation″,
Phys. Lett. B 647 (2007) 88.

R. K. Bradford, R. A. Schumacher et al. [CLAS Collaboration]

„First measurement of beam-recoil observables C(x) and C(z) in hyperon photoproduction″,
Phys. Rev. C 75 (2007) 035205, [arXiv:nucl-ex/0611034].

J. Ahrens et al. [A2- and GDH-Collaborations]

„Measurement of the helicity dependence for the γ p→ nπ⁺ channel in the second resonance region″,
Phys. Rev. C. 74 (2006) 045204.

R. Bradford, R. A. Schumacher, J. W. C. McNabb, L. Todor et al. [CLAS Collaboration]

„Differential cross sections for γ + p → K⁺ + Y for Λ and Σ⁰ hyperons″,
Phys. Rev. C 73 (2006) 035202, [arXiv:nucl-ex/0509033].

M. Battaglieri, R. De Vita, V. Kubarovsky, L. Guo, G. S. Mutchler, P. Stoler, D. P. Weygand et al. [CLAS Collaboration]

„Search for Θ⁺(1540) pentaquark in high statistics measurement of γ p → K⁰– K⁺n at CLAS″,
Phys. Rev. Lett. 96 (2006) 042001, [arXiv:hep-ex/0510061].

S. Strauch, B. L. Berman et al. [CLAS Collaboration]

„Beam-helicity asymmetries in double charged pion photoproduction on the proton″,
Phys. Rev. Lett. 95 (2005) 162003, [arXiv:hep-ex/0508002].

J. Ahrens et al. [A2- and GDH-Collaborations]

„Measurement of the G asymmetry for the γp → Nπ channels in the Δ(1232) resonance region″,
Eur. Phys. J. A 26 (2005) 135.

J. Ahrens et al.

„Measurement of the π⁺ meson polarizabilities via the γp → γπ⁺ n reaction″,
Eur. Phys. J. A 23 (2005) 113.

J.D. Kellie, P. Clive, R. Beck, K. Livingston, I.J.D. MacGregor, J.C. McGeorge, A. Schmidt, D.P. Watts

„The selection and performance of diamond radiators used in coherent bremsstrahlung experiments″,
NIM A 545 (2005) 164-180.

J. Ahrens et al. [GDH- and A2-Collaborations]

„Intermediate resonance excitation in the γp → pπ⁰π⁰ reaction″,
Phys. Lett. B 624 (2005) 173.

J. W. C. McNabb, R. A. Schumacher, L. Todor et al. [CLAS Collaboration]

„Hyperon photoproduction in the nucleon resonance region″,
Phys. Rev. C 69 (2004) 042201, [arXiv:nucl-ex/0305028].

B. Krusche, J. Lehr et al.

„Photoproduction of π⁰-mesons from nuclei″,
Eur. Phys. J. A 22(2004) 277-291.

J. Ahrens et al. [GDH- and A2-Collaborations]

„Helicity dependence of the γp → Nπ channels and multipole analysis in the Delta region″,
Eur. Phys. J. A 21 (2004) 323.

K. Kossert, M. Camen, F. Wissmann et al.

„Quasi-free π⁰ photoproduction from the bound nucleon″,
Eur. Phys. J. A 19 (2004) 391.

M. Pfeiffer et al.

„Photoproduction of η ³He″,
Phys. Rev. Lett. 92 (2004) 252001.

Sonderforschungsbereich 16

A1. Spektroskopie von Baryonen-Resonanzen

Publikationen