Meson-nucleus potentials and the search for meson-nucleus bound states

Abstract

Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on $K^{+},K^0,K^{-},\eta ,{\eta }^{\prime },\omega$, and $\varphi$ mesons are presented and compared with theoretical predictions. The interaction of $K^{+}$ and $K^0$ mesons with nuclei is found to be weakly repulsive, while the $K^{-},\eta ,{\eta }^{\prime },\omega$ and $\varphi$ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the $\eta$ and ${\eta }^{\prime }$ mesons.

86 pages, 67 figures

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Cited by in corpus (35)

• Sub-threshold production of K^{0}_{s} mesons and Λ hyperons in Au(1.23A GeV)+Au
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• The reaction $\pi N\to \omega N$ in a dynamical coupled-channel approach
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• $\eta$ and ${\eta }^{\prime }$ mesons in nuclear matter and nuclei
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• Phases and dynamics of quantum droplets in the crossover to two-dimensions
• Bound states of ${}_{\varphi }^9$Be and ${}_{\varphi \varphi }^6$He nuclei with $\varphi$+$\alpha$+$\alpha$ and $\varphi$+$\varphi$+$\alpha$ cluster models
• Kaon Structure in the Nuclear Medium within the Light Front Approach
• The $\varphi NN,J/\psi NN,{\eta }_{c}NN$ systems based on HAL QCD interactions
• Absorption of $\omega$ and $\varphi$ mesons in the inclusive photonuclear reaction
• Study of light $\varphi$-mesic nuclei with HAL QCD $\varphi N$ interactions
• On the determination of the $D$ meson width in the nuclear medium with the transparency ratio
• Lambda beta-decay in-medium
• Interactions of $\omega$-Mesons in Nuclear Matter and with Nuclei
• Theoretical study of the $\gamma d\to {\pi }^0\eta d$ reaction
• In-medium electromagnetic form factors of pseudoscalar mesons from the quark model
• Antikaon-induced $K_1(1270{)}^{+}$ meson production on nuclei near threshold
• Medium effects in antikaon-induced ${\Xi }^{-}$ hyperon production on nuclei near threshold
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• Near-threshold ${\eta }^{\prime }$ meson production in ${\pi }^{-}A$ reactions
• Revisiting ${\eta }^{\prime }(958)$ nuclear states
• The ${\eta }^{\prime }N$ interaction from the ${\eta }^{\prime }p$ correlation function
• $B_c^{\pm }$-${}^{12}$C states and detailed study of momentum space method for ${\rm Y}$- and ${\eta }_b$-nucleus bound states
• Kaon production in the HADES experiment in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=2.4$ GeV
• Absorption of $\psi (2S)$ mesons in nuclei
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• Probing the existence of η^3He mesic nucleus with a few-body approach
• Forward coherent $\omega$ and $\varphi$ mesons production in the photon induced reaction on nuclei
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• Feasibility of the observation of ${\eta }^{\prime }$ mesic nuclei in the semi-exclusive ${}^{12}$C($p,dp$) reaction
• Insights into the exotic charged states $Z_b(10610)$ and $Z_b(10650)$ from their photoproduction off nuclei