η-helium quasi-bound states

Willis, N.; Bornec, Y. Le; Zghiche, A.; Wilkin, C.; Wurzinger, R.; Bing, O.; Boivin, M.; Courtat, P.; Gacougnolle, R.; Hibou, F.; Martin, J.; Plouin, F.; Tatischeff, B.; Yonnet, Jean‐Paul

doi:10.1016/s0370-2693(97)00650-3

Cited by 90 publications

(139 citation statements)

References 22 publications

Supporting

Mentioning

128

Contrasting

Order By: Relevance

“…It turns out that the new data do not fully agree with each other and that still not enough observables are known to extract the s wave amplitudes. The situation is slightly better for the η 4 He final state, which has been studied in d + d interactions making use of unpolarised beams [73], [119], [118] as well as polarised beams [120]. The number of measured points is not sufficient yet to also extract the effective range with sufficient certainty from the data.…”

Section: Discussionmentioning

confidence: 99%

“…The solid curve is a fit with scattering length and effective range, while the dashed curve is one applying the two pole expansion (119). the beam energy with thus almost no need to apply the smearing, while ANKE get rid of data below threshold by the smearing method.…”

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

confidence: 99%

“…Measurements of reaction d + d → η+ 4 He were reported in [118], [119], [73] and more recently in [120]. The last one is here sometimes also called GEM data.…”

Section: The Reaction D + D → η+ 4 Hementioning

confidence: 99%

“…In a simultaneous analysis of the d + p → 3 He+η reaction and the d + d → 4 He+η reaction in terms of a simple optical model approach [119] it was found that for the possible binding energies the relation B η ( 3 He + η) < B η ( 4 He + η) holds. However, in the measurements with a polarised beam on which the analysis was based, the full polar angle could not be measured.…”

Section: The Reaction D + D → η+ 4 Hementioning

confidence: 99%

See 3 more Smart Citations

Search for quasi boundηmesons

Machner

2015

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

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

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

confidence: 99%

“…Measurements of reaction d + d → η+ 4 He were reported in [118], [119], [73] and more recently in [120]. The last one is here sometimes also called GEM data.…”

Section: The Reaction D + D → η+ 4 Hementioning

confidence: 99%

Section: The Reaction D + D → η+ 4 Hementioning

confidence: 99%

See 2 more Smart Citations

Search for quasi boundηmesons

Machner

2015

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

View full text Add to dashboard Cite

show abstract

“…Since the final s-wave is forbidden in the γ 4 He → η 4 He reaction, and neither the p 3 H → η 4 He nor n 3 He → η 4 He is experimentally appealing, this final state has been studied in a series of measurements of the dd → 4 He η reaction [272,273,274,275]. It is first important to note that the threshold cross section is about fifty times lower than that of pd → 3 He η, so that its measurement represents much more of a challenge.…”

Section: The Dd → 4 He η Reactionmentioning

confidence: 99%

Production of η and η′ mesons on nucleons and nuclei

Krusche¹,

Wilkin²

2015

Progress in Particle and Nuclear Physics

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Meson production at CELSIUS

Johansson¹

2003

Refereed and Selected Contributions From International Conference on Quark Nuclear Physics

View full text Add to dashboard Cite

η-helium quasi-bound states

Cited by 90 publications

References 22 publications

Search for quasi boundηmesons

Search for quasi boundηmesons

Production of η and η′ mesons on nucleons and nuclei

Meson production at CELSIUS

Contact Info

Product

Resources

About