ASTROPHYSICAL S-FACTOR OF THE DIRECT 3He(α,γ)7Be CAPTURE REACTION IN CLUSTER MODELS

Oct 17, 2020, 11:45 AM
25m
Online

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Oral report Section 2. Experimental and theoretical studies of nuclear reactions. Section 2. Experimental and theoretical studies of nuclear reactions

Speaker

S.A. Turakulov (Institute of Nuclear Physics, Academy of Sciences, 100214, Ulugbek, Tashkent, Uzbekistan; Tashkent Railway Engineering Institute, Uzbekistan)

Description

The direct ${}^3$He(α,γ)${}^7$Be radiative capture reaction is studied in the framework of two- and three-body potential cluster models [1,2]. E1 and E2 transitions are described at the long-wavelength approximation. The two-body model is based on a simple Gaussian form $α^{3}$He-potential of Dubovichenko $V_{D}^{a}$ from Ref.[1], with a modification in d waves. The new potential parameters are $V_{0}$=-180 MeV, α=0.4173 $fm^{-2}$ and $V_{0}$=-190 MeV, α=0.4017 $fm^{-2}$ in the $d_{3/2}$ and $d_{5/2}$ partial waves, respectively. The potential describes correctly the phase shifts in the $s$, $p$, $d$ and $f$ waves and binding energies of the ground $p_{3/2}$ and the first excited $p_{1/2}$ bound states. As can be seen in Fig.1, the modification of the potential in $d$ waves allows to improve the description of the astrophysical S factor for the direct ${}^3$He(α,γ)${}^7$Be radiative capture reaction at intermediate energies E>0.5 MeV in comparison with the results of Ref.[1]. In the three-body model the ${}^7$Be nucleus is described as a bound state of α+p+d in the Hyperspherical Lagrange mesh method. The initial state is factorized into the p+d bound state and the α+${}^3$He scattering state. The αd-potential is from Ref.[2], while αN-potential was taken from Ref.[3]. The pd-potential of the Gaussian form [4] with parameters $V_0$=-34.92 MeV, α=0.15 $fm^{-2}$ and $V_0$=2.4 MeV, α=0.01 ${fm}^{-2}$ are used in the even and odd partial waves, respectively. The α${}^3$He-potential is the same as in the two-body model. The three body bound state wave functions of ${}^7$Be was corrected at R=6 fm with the help of the Whittaker asymptotics.

Fig. 1. (a) Astrophysical S factor within the two- and three-body models in comparison with the available experimental data. Panel (b) highlights the low energy region.

  1. E.M. Tursunov et al. // Phys. Rev. C. 2018. V.97. id.035802.
  2. E.M. Tursunov et al. // Phys. Rev. C. 2018. V.98. id.055803.
  3. V.T. Voronchev et al. // Few-Body Syst. 1995. V. 18. p. 191.
  4. S. Dubovichenko et al. // Phys. Elem. Part. At. Nucl. 1997. V.28. p.1529.

Primary authors

E.M. Tursunov (Institute of Nuclear Physics, Academy of Sciences, 100214, Ulugbek, Tashkent, Uzbekistan) S.A. Turakulov (Institute of Nuclear Physics, Academy of Sciences, 100214, Ulugbek, Tashkent, Uzbekistan; Tashkent Railway Engineering Institute, Uzbekistan) E.M. Dusnazarov (Institute of Nuclear Physics, Academy of Sciences, 100214, Ulugbek, Tashkent, Uzbekistan)

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