Abstract
The basic condition for Efimov states is the existence of resonant two-body forces. A system of three particles with resonant two-body interactions may form bound states, the so called Efimov trimers, even when any two of the particles are unable to bind. Inspired by this idea we have analysed a set of data from the \(^6\hbox {Li}+^6\hbox {Li}\rightarrow 3 \alpha \) reaction measured in a kinematically complete experiment at 3.1 MeV of beam energy, corresponding to 29.6 MeV of excitation energy in \(^{12}\hbox {C}\), with the characteristic that the 3\(\alpha \) channel is fed by three \(^8\hbox {Be}\) states in the same event. A strong enhancement in the \(\alpha \)–\(\alpha \) coincidence yield is experienced for these events. Evidence of three \(^8\hbox {Be}\) levels within the same 3\(\alpha \) event suggests that one particle is exchanged between the other two. According to quantum mechanics, this is a condition for Efimov states to occur and for which no observation exists yet in nuclei. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3\(\alpha \) particle correlation.
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References
V. Efimov, Energy levels arising from resonant two-body forces in a three-body system. Phys. Lett. B 33, 563 (1970)
T. Kraemer et al., Evidence for Efimov quantum states in an ultracold gas of caesium atoms. Nature 440, 315 (2006)
S.E. Pollack, D. Dries, R.G. Hulet, Universality in three- and four-body bound states of ultracold atoms. Science 326, 1683 (2009)
R. Pires et al., Observation of Efimov resonances in a mixture with extreme mass imbalance. Phys. Rev. Lett. 112, 250404 (2014)
V. Efimov, Giant trimers true to scale. Nat. Phys. 5, 533 (2009)
R. Higa, H.W. Hammer, U. van Kolck, \(\alpha \)–\(\alpha \) scattering in halo effective field theory. Nucl. Phys. A 809, 171 (2008)
P. Naidon, S. Endo, Efimov physics: a review. Rep. Prog. Phys. 80, 5 (2016)
S. Ali, A. Bodmer, Phenomenological \(\alpha \)–\(\alpha \) potentials. Nucl. Phys. 80, 99 (1966)
H. Suno, Y. Suzuki, P. Descouvemont, Triple-\(\alpha \) continuum structure and Hoyle resonance of \(^{12}\)C using the hyperspherical slow variable discretization. Phys. Rev. C 91, 014004 (2015)
A. Tumino et al., Triple \(\alpha \) resonances in the \(^6\text{ Li }\,+\,^6\text{ Li }\) reaction at low energy. Phys. Lett. B 750, 59 (2015)
C. Spitaleri et al., Quasifree mechanism in the \(^6\text{ Li }\,+\,^6\text{ Li }\rightarrow 3\alpha \) reaction at low energy. Phys. Rev. C 91, 024612 (2015)
E. Braaten, H.W. Hammer, Universality in few-body systems with large scattering length. Phys. Rep. 428, 259 (2006)
D. Dell’Aquila et al., High-precision probe of the fully sequential decay width of the Hoyle state in \(^{12}\)C. Phys. Rev. Lett. 119, 132501 (2017)
R. Smith et al., New measurement of the direct 3\(\alpha \) decay from the \(^{12}\)C Hoyle state. Phys. Rev. Lett. 119, 132502 (2017)
C. Bertulani, P. Danielewicz, Danielewicz Introduction to Nuclear Reactions (Taylor and Francis, London, 2004)
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This article belongs to the Topical Collection “Critical Stability of Quantum Few-Body Systems”.
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Tumino, A., Bonasera, A., Giuliani, G. et al. Triple \(\alpha \) Resonances and Possible Link to the Efimov Trimers. Few-Body Syst 59, 54 (2018). https://doi.org/10.1007/s00601-018-1374-y
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DOI: https://doi.org/10.1007/s00601-018-1374-y