C5. Study of QCD-dynamics in η- and η’-production and decays

R. Beck, U. Wiedner

Certain decays of η and η’ mesons are forbidden by conservation laws. If observed, it is important to determine the decay parameters that provide information about symmetries in QCD and its theoretical description. The cross section of excited η mesons in photoproduction, is a missing piece in the quest to understand their exact composition out of quarks and gluons.

Publications

Published and accepted papers

B.M.K. Nefkens et al. [A2 Collaboration]

„New measurement of the rare decay η → π⁰γγ with the Crystal Ball/TAPS detectors at the Mainz Microtron″,
Phys.Rev. C90 (2014) no.2, 025206

P. Aguar-Bartolomlé et al. [A2 Collaboration]

„New determination of the η transition form factor in the Dalitz decay η → e⁺e^-γ with the Crystal Ball/TAPS detectors at the Mainz Microtron″,
Phys.Rev. C89 (2014) no.4, 044608, [arXiv:1309.5648 [hep-ex]].

A. Nikolaev et al.[MAMI, TAPS and A2 Collaborations]

„Determination of the η mass with the Crystal Ball at MAMI-B″,
Eur.Phys.J. A50 (2014) 58, [arXiv:1207.3710 [nucl-ex]].

M. Ablikim et al. [BESIII Collaboration]

„First observation of η(1405) decays into f₀(980)π⁰″,
Phys. Rev. Lett. 108 (2012) 182001, [arXiv:1201.2737 [hep-ex]].

M. Ablikim, M. N. Achasov, D. Alberto, Q. An, Z. H. An, J. Z. Bai, R. Baldini and Y. Ban et al.

„ηπ⁺π^- Resonant Structure around 1.8 GeV/c² and η(1405) in J/ψ → ωηπ⁺π^-″,
Phys. Rev. Lett. 107 (2011) 182001, [arXiv:1107.1806 [hep-ex]].

H. Berghauser, V. Metag, A. Starostin et al.

„Determination of the η-transition form factor in the γ p → p η → p γ e⁺e^- reaction″,
Phys. Lett. B 701 (2011) 562.

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]].

U. Wiedner

„Future Prospects for Hadron Physics at PANDA″,
Prog. Part. Nucl. Phys. 66 (2011) 477, [arXiv:1104.3961 [hep-ex]].

M. Ablikim et al. [BESIII Collaboration]

„Measurement of the Matrix Element for the Decay η' → ηπ⁺π^-″,
Phys. Rev. D 83 (2011) 012003, [arXiv:1012.1117 [hep-ex]].

S. Schumann, B. Boillat, E. J. Downie, P. Aguar-Bartolome et al. [Crystal Ball at MAMI and TAPS and A2 Collaborations]

„Radiative π⁰-photoproduction on protons in the Δ⁺(1232) region″,
Eur. Phys. J. A 43 (2010) 269, [arXiv:1001.3626 [hep-ex]].

M. Unverzagt et al. [Crystal Ball at MAMI and TAPS and A2 Collaborations]

„Determination of the Dalitz plot parameter α for the decay η → 3π⁰ with the Crystal Ball at MAMI-B″,
Eur. Phys. J. A 39 (2009) 169, [arXiv:0812.3324 [hep-ex]].

S. Prakhov et al. [Crystal Ball at MAMI and A2 Collaborations]

„Measurement of the Slope Parameter α for the η → 3π⁰ decay with the Crystal Ball at MAMI-C″,
Phys. Rev. C 79 (2009) 035204, [arXiv:0812.1999 [hep-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]].

A. Starostin, B. M. K. Nefkens, J. Ahrens, J. R. M. Annand, H. J. Arends, K. Bantawa, P. A. Bartolome and R. Beck et al.

„Search for the charge-conjugation-forbidden decay ω → ηπ⁰″,
Phys. Rev. C 79 (2009) 065201.

C. Adolph, ... , Ulf-G. Meißner, et al. [WASA-at-COSY Collaboration]

„Measurement of the η → 3 π⁰ Dalitz Plot Distribution with the WASA Detector at COSY″,
Phys. Lett. B 677 (2009) 24.

C. Amsler, A. V. Anisovich, C. A. Baker, B. M. Barnett, C. J. Batty, P. Blum, K. Braune and V. Crede et al.

„Production and decay of η'(958) and η(1440) in anti-p p annihilation at rest″,
Eur. Phys. J. C 33 (2004) 23.

Collaborative Research Centre 16

C5. Study of QCD-dynamics in η- and η’-production and decays

Publications