The discrete Efimov scaling behavior, well-known in the low-energy spectrum of three-body bound systems for large scattering lengths (unitary limit), is identified in the energy dependence of atommolecule elastic cross-section in mass imbalanced systems. That happens in the collision of a heavy atom with mass mH with a weakly-bound dimer formed by the heavy atom and a lighter one with mass mL mH . Approaching the heavy-light unitary limit the s−wave elastic cross-section σ will present a sequence of zeros/minima at collision energies following closely the Efimov geometrical law. Our results open a new perspective to detect the discrete scaling behavior from low-energy scattering data, which is timely in view of the ongoing experiments with ultra-cold binary mixtures having strong mass asymmetries, such as Lithium and Caesium or Lithium and Ytterbium.The Efimov effect [1] refers to a discrete scaling symmetry, which emerges in the quantum three-body system at the unitary limit (when the two-body scattering lengths diverge). The optimal condition to observe this discrete scaling symmetry in cold atomic laboratories is now found for heteronuclear three-atom systems with large mass asymmetry and large interspecies scattering lengths. In the Efimov (unitary) limit, the shallow three-body levels are geometrically spaced, namely the ratio between the binding energies of the n and n + 1 levels is given by B = exp (2π/s 0 ), where s 0 is a universal constant, which depends only on the mass ratio and not on the details of the interaction. The energy ratio for three identical bosons is exp (2π/s 0 ) ≈ 515, decreasing for the case of two heavy particles and light one. When m L /m H = 0.01, for example, the value of this energy ratio goes to exp (2π/s 0 ) = 4.698 [2].The Efimov geometric scaling factor has been measured in a cold-atom experiment with mass-imbalance mixtures of Caesium ( 133 Cs) and Lithium ( 6 Li) gases by different groups [3,4]. The ratio between the positions of two successive peaks in the three-body recombination rate, obtained by varying the large negative scattering lengths (a HL ), was found in close agreement with the theory. Complementary to this finding, a fingerprint of the Efimov scaling can be found in the s−wave ultracold atom-molecule cross-section by varying the incident momentum energy k instead of the scattering lengths. Natural, but not yet evidenced experimentally or theoretically. What we expect is beyond the trimer crossing the corresponding continuum, which creates the resonant enhancement of the inelastic collisions of Caesium atoms with Caesium dimers, as observed by Knoop et al. [5].Furthermore, there is an evident strong interest in ultra-cold heteronuclear atom-molecule collisions by experimental groups [6][7][8]. Trap setups with ultra-cold degenerated mixtures of alkali-metal-rare-earth molecules with strong mass-imbalanced systems as Ytterbium and Lithium ( 174,173 Yb− 6 Li) have also been reported in Refs. [9,10]. We should mention that on the theory side [11], reactions at ...
The recently developed chiral nucleon-nucleon
No abstract
Abstract. Two-and three-particles photodisintegration of the triton is investigated in a three-dimensional (3D) Faddeev approach. For this purpose the Jacobi momentum vectors for three particles system and spinisospin quantum numbers of the individual nucleons are considered. Based on this picture the three-nucleon Faddeev integral equations with the two-nucleon interaction are formulated without employing the partial wave decomposition. The single nucleon current as well as π− and ρ− like exchange currents are used in an appropriate form to be employed in 3D approach. The exchange currents are derived from AV18 NN force. The two-body t-matrix, Deuteron and Triton wave functions are calculated in the 3D approach by using AV18 potential. Benchmarks are presented to compare the total cross section for the two-and threeparticles photodisintegration in the range of Eγ < 30 M eV . The 3D Faddeev approach shows promising results.
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