Constraining the optical potential in the search for η-mesic 4He

Skurzok, M.; Moskal, P.; Kelkar, N. G.; Hirenzaki, S.; Nagahiro, Hideko; Ikeno, Natsumi

doi:10.1016/j.physletb.2018.04.047

Cited by 21 publications

(15 citation statements)

References 62 publications

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“…With the results obtained in Ref. [39], most predictions of an η 4 He bound state seem to be excluded.…”

Section: Introductionmentioning

confidence: 68%

“…As a consequence, the analysis in Ref. [39] made further strong constraints on the η-4 He optical potential. With the results obtained in Ref.…”

Section: Introductionmentioning

confidence: 95%

“…[38] were compared with the experimental data below the η production threshold, with the WASA-at-COSY excitation functions for the dd → 3 HeNπ reactions in Ref. [39], where no clear signal of the η 4 He bound state was found. As a consequence, the analysis in Ref.…”

Section: Introductionmentioning

confidence: 99%

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$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

Xie

Oset

2019

Eur. Phys. J. A

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We analyze the data on the total cross sections for the dd → η 4 He reaction close to threshold and look for possible η 4 He bound states. We develop a framework in which the η 4 He optical potential is the key ingredient, rather than parameterizing the scattering matrix, as is usually done. The strength of this potential, together with some production parameters, are fitted to the available experimental data. The relationship of the scattering matrix to the optical potential is established using the Bethe-Salpeter equation and the η 4 He loop function incorporates the range of the interaction given by the experimental 4 He density. However, when we look for poles of the scattering matrix, we get poles in the bound region, poles in the positive energy region or no poles at all. If we further restrict the results with constraints from a theoretical model with all its uncertainties the bound states are not allowed. However, we find a bump structure in |T | 2 of the η 4 He → η 4 He amplitude below threshold for the remaining solutions.

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“…With the results obtained in Ref. [39], most predictions of an η 4 He bound state seem to be excluded.…”

Section: Introductionmentioning

confidence: 68%

“…As a consequence, the analysis in Ref. [39] made further strong constraints on the η-4 He optical potential. With the results obtained in Ref.…”

Section: Introductionmentioning

confidence: 95%

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$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

Xie

Oset

2019

Eur. Phys. J. A

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“…2.1). This result was compared [55] with the theoretical estimations [37]. The experimental data allow to exclude a wide range of possible parameters for η− 4 He optical potential.…”

Section: Previous Experiments On Search For η-Mesic Nucleimentioning

confidence: 92%

Search for η-mesic ³He in non-mesonic final state

2019

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The experiment on searching for η-mesic 3He nucleus was performed in May 2014 at COSY accelerator in Juelich by WASA-at-COSY Collaboration. The measurements were carried out using ramped beam technique which allows for the slow and continuous beam momentum change near the threshold of η meson creation. The luminosity was obtained based on pd → 3Heη reaction and quasielastic proton-proton scattering. The bound state of η-meson and 3He nucleus is searched for in pd → 3He2γ and pd → 3He6γ channels. The analysis is still in progress and the estimated upper limit value is on the level of few nanobarns.

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“…Coherent η photoproduction on 3 He also shows a strong threshold enhancement, and the angular distribution of η emission is rather flat near the threshold as compared with the distribution expected based on the nuclear form factor [16]. The WASA-at-COSY collaboration has searched for η-mesic 3 He and 4 He nuclei in the pd and dd reactions, respectively, by detecting daughter particles from η or N * in a nucleus [17][18][19][20][21]. No convincing evidence for an η-mesic nucleus has yet been obtained.…”

mentioning

confidence: 99%

Resonance-like structure near the $ηd$ threshold in the $γ{d}${$\to$}$π^0η{d}$ reaction

Ishikawa,

Fujimura,

Fukasawa

et al. 2021

Preprint

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To investigate the interaction between the nucleon N and nucleon resonance N (1535)1/2 − , the ηd threshold structure, connected to the isoscalar S-wave N -N (1535)1/2 − system, has been experimentally studied in the γd→π 0 ηd reaction at incident photon energies ranging from the reaction threshold to 1.15 GeV. A strong enhancement is observed near the ηd threshold over the three-body phase-space contribution in the ηd invariant-mass distribution. An analysis incorporating the known isovector resonance D12 with a spin-parity of 2 + in the π 0 d channel has revealed the existence of a narrow isoscalar resonance-like structure D ηd with 1 − in the ηd system. The Breit-Wigner mass of D ηd is found to be 2.425 −0.006 +0.003 GeV, located just close to the ηd threshold, and the width is 0.034 +0.004 −0.003 GeV. The D ηd would be a predicted isoscalar 1 − ηN N bound state from the ηN N and πN N coupled-channel calculation, or ηd virtual state owing to strong ηd attraction.

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Constraining the optical potential in the search for η-mesic 4He

Cited by 21 publications

References 62 publications

$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

Search for η-mesic ³He in non-mesonic final state

Resonance-like structure near the $ηd$ threshold in the $γ{d}${$\to$}$π^0η{d}$ reaction

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Constraining the optical potential in the search for η-mesic 4He

Cited by 21 publications

References 62 publications

$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

$\eta$η-4He interaction from the $dd \rightarrow \eta$dd→η4He reaction near threshold

Search for η-mesic 3He in non-mesonic final state

Resonance-like structure near the $ηd$ threshold in the $γ{d}${$\to$}$π^0η{d}$ reaction

Contact Info

Product

Resources

About

Search for η-mesic ³He in non-mesonic final state