Measurement of in the S11 resonance

Betigeri, M.G.; Bojowald, J.; Budzanowski, A.; Chatterjee, A.; Drochner, M.; Ernst, J.; Förtsch, S. V.; Freindl, L.; Frekers, D.; Garske, W.; Grewer, K.; Hamacher, A.; Igel, S.; Ilieva, J.; Jahn, R.; Jarczyk, L.; Kemmerling, G.; Kilian, K.; Kliczewski, S.; Klimala, W.; Kolev, D.; Kutsarova, T.; Lieb, J.; Lippert, G.; Machner, H.; Magiera, A.; Nann, H.; Pentchev, L.; Plendl, H. S.; Protić, D.; Razen, B.; Rossen, P. von; Roy, Bikram; Siudak, R.; Smyrski, J.; Strzalkowski, A.; Tsenov, R.; Zolnierczuk, Piotr; Zwoll, K.

doi:10.1016/s0370-2693(99)01456-2

Cited by 40 publications

(33 citation statements)

References 20 publications

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“…Data are from Refs. [106], [107], [108], [109], [110], [111], [112]. Those close to threshold are shown in Fig.…”

Section: The Reaction D + P → 3 He+ηmentioning

confidence: 96%

Search for quasi boundηmesons

Machner

2015

J. Phys. G: Nucl. Part. Phys.

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The search for a quasi bound η meson in atomic nuclei is reviewed. This tentative state is studied theoretically as well as experimentally. The theory starts from elastic η nucleon scattering which is derived from production data within some models. From this interaction the η nucleus interaction is derived. Model calculations predict binding energies and widths of the quasi bound state. Another method is to derive the η nucleus interaction from excitation functions of η production experiments. The s wave interaction is extracted from such data via final state interaction theorem. We give the derivation of s wave amplitudes in partial wave expansion and in helicity amplitudes and their relation to observables. Different experiments extracting the final state interaction are discussed as are production experiments. So far only three experiments give evidence for the existence of the quasi bound state: a pion double charge exchange experiment, an effective mass measurement, and a transfer reaction at recoil free kinematics with observation of the decay of the state.

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“…Data are from Refs. [106], [107], [108], [109], [110], [111], [112]. Those close to threshold are shown in Fig.…”

Section: The Reaction D + P → 3 He+ηmentioning

confidence: 96%

Search for quasi boundηmesons

Machner

2015

J. Phys. G: Nucl. Part. Phys.

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“…There have been numerous measurements of the pd → 3 He η reaction at low energies over the last 30 years, where the 3 He nucleus was detected and the η meson identified through the missing mass in the reaction [181,182,239,240,241,242,243,244,245,246,247,248]. The statistical precision is generally reasonable but the systematic uncertainties, mainly associated with the overall normalization, range from about 7% in the Saclay measurement [243] up to twice that in most of the other data, except for the large errors at COSY-11 [246].…”

Section: The Unpolarized Pd → 3 He η Reactionmentioning

confidence: 99%

“…The data are taken from Refs. [241] (black filled circles), [243] (open magenta triangles), [244] (open green circle), [245] (red crosses), and [247] (blue stars). Systematic errors are not shown.…”

Section: The Unpolarized Pd → 3 He η Reactionmentioning

confidence: 99%

“…Although the near-threshold data could indeed be described in terms of pp → dπ + followed by π + n → ηp, when this approach was tried at higher energies [255] it predicted differential cross sections that were backward peaked, in complete contrast to the experimental data [244,245,248]. The kinematics become less magic away from threshold and it is possible that the defect in the model is associated with the neglect of the off-shell behaviour of the pp → dπ + amplitude.…”

Section: The Unpolarized Pd → 3 He η Reactionmentioning

confidence: 99%

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Production of η and η′ mesons on nucleons and nuclei

Krusche¹,

Wilkin²

2015

Progress in Particle and Nuclear Physics

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The production of η and η mesons in photon-and hadron-induced reactions on free and quasifree nucleons and on nuclei is reviewed. The extensive database on γN → ηN , for both proton and neutron targets, is described in detail and its implications for the search for N resonances much heavier than the dominant S 11 (1535) discussed. Though less is currently known about the production of the η or of ηπ pairs, these also offer tantalizing prospects in the search for the missing isobars. The more limited data available on pion-induced production are still necessary ingredients in the partial wave analysis discussed.The production of the η-meson in pp and pn collisions shows once again the strong influence of the S 11 (1535) isobar, which is in contrast to the relatively weak behaviour seen near threshold for η production. This difference is reflected in the important final state interaction effects of the η in nuclei that may even lead to this meson being "bound" in some systems. The evidence for this is reviewed for both γA and pA collisions. The inclusive photoproduction of η, η , and ηπ pairs from nuclei provides further information regarding the production mechanism and the interaction of the η and η with nuclei and the ηπ pairs may even allow access to low mass ηA systems that are forbidden in direct single-meson photoproduction.

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“…In the very near threshold region, the p d → 3 He η reaction has been studied in great detail [1][2][3][4][5], whereas at higher excess energies Q the amount of available data is limited [6][7][8][9]. Moreover, while the data from ANKE [6] and WASA/PROMICE [7,8] suggest a plateau in the total cross section for higher Q-values, recent results from the WASA-at-COSY experiment [10] suggest an unexpected narrow variation of the total cross section at Q = 48.8 MeV as can be seen in Fig.1.…”

Section: Introductionmentioning

confidence: 99%

Studies onηmeson production and theC-parity violating decayη→π⁰e⁺e⁻with WASA-at-COSY

Hüsken

Bergmann

Demmich

et al. 2016

EPJ Web of Conferences

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Abstract. The WASA-at-COSY experiment is a near 4π detector, located at the Forschungszentrum Jülich (Germany). It is highly suited to study both the production of light mesons in hadron collisions and their subsequent decays. Current investigations include a study on the energy dependence of the production cross section and angular distributions of the η meson in the proton-deuteron fusion reaction p d → 3 He η, as well as a search for beyond standard model physics in the C-parity violating decay η → π 0 e + e − . The status of both these analyses and preliminary results are presented.

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Measurement of in the S11 resonance

Cited by 40 publications

References 20 publications

Search for quasi boundηmesons

Search for quasi boundηmesons

Production of η and η′ mesons on nucleons and nuclei

Studies onηmeson production and theC-parity violating decayη→π⁰e⁺e⁻with WASA-at-COSY

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Measurement of in the S11 resonance

Cited by 40 publications

References 20 publications

Search for quasi boundηmesons

Search for quasi boundηmesons

Production of η and η′ mesons on nucleons and nuclei

Studies onηmeson production and theC-parity violating decayη→π0e+e−with WASA-at-COSY

Contact Info

Product

Resources

About

Studies onηmeson production and theC-parity violating decayη→π⁰e⁺e⁻with WASA-at-COSY