Astrophysical S -factor of p2H radiative capture

Abstract

Abstract. The astrophysical S-factor of p 2 H radiative capture in the energy range down to 1 keV is considered in the potential cluster model with the classification of orbital states according to Young's scheme symmetry. It is shown that the approach used, which takes into account the E1 transition only, gives a good description of the new experimental data for two potentials of the bound state of the The radiative p + 2 H → 3 He + γ capture is a part of the hydrogen cycle and gives a considerable contribution to the energy efficiency of thermonuclear reactions [1] which account for burning of the Sun and stars of our Universe. The interacting nuclear particles of the hydrogen cycle have a minimal value which is a potential barrier. Thus, it is the first chain of nuclear reactions which can take place at ultralow energies and star temperatures. Then, for this chain, the process of the radiative p 2 H capture is the basic process for the transition from the primary proton fusion p + p → 2 H + e − + ν e to the final process 3 He+ 3 He → 4 He+2p [2] in the p-p chain. That is why the theoretical and experimental investigation of the radiative p 2 H capture in detail is of fundamental interest not only for nuclear astrophysics, but also for nuclear physics of ultralow energies and lightest atomic nuclei.We will discuss the astrophysical S-factors on the basis of a potential cluster model which takes into account the supermultiplet symmetry of wave functions (WF) with the splitting of orbital states according to Young's schemes. This approach allows us to analyse the structure of inter-cluster interactions, detecting allowed and forbidden states in the interaction potential, and thus, the number of WF nodes of the relative motion of clusters [3,4].The total cross-sections of the photoprocesses of the lightest nuclei were considered in this approach in our work [4]. E1 transitions resulting from the orbital part of the electric operator Q Jm (L) were taken into account in these calculations of the photodecays of 3 He and 3 H a e-mail: albert-j@yandex.ru nuclei into p 2 H and n 2 H channels. The values of E2 crosssections and cross-sections depending on the spin part of the electric operator turned out to be several times less. Further, it was assumed that E1 electric transitions in the N 2 H system are possible between the "pure" (scheme {3}) 2 S state of 3 H and 3 He nuclei and the doublet 2 P scattering state mixed according to Young's schemes {3} + {21}.To calculate photonuclear processes in the systems under consideration the nuclear part of the potential of intercluster p 2 H and n 2 H interactions is represented aswith a point-like Coulomb potential, V 0 -the Gaussian attractive part, and V 1 -the exponential repulsive part. The potential of each partial wave was constructed so that it would correctly describe the respective partial phase shift of the elastic scattering [5]. Using this concept, the potentials of the p 2 H interaction for scattering processes were received, parameters of such potentials were ful...

Study of the nucleon radiative captures 8Li(n,γ)9Li, 9Be(p,γ)10B, 10Be(n,γ)11Be, 10B(p,γ)11C, and 16O(p,γ)17F at thermal and astrophysical energies

“…6 However, overcoming such a mass gap is possible through the chain of reactions 4 He(2n,γ) 6 He(2n,γ) 8 He(β -) 8 Li(n,γ) 9 Li(β -) 9 Be on this stage, 7,8 where the process considered here is also presented. This chain would provide an alternative way toward heavier isotopes such as 36 S, 40 Ar, 46 Ca, and 48 Ca. However, it is very important to know to what extent this chain can compete with the process 8 Li(β − ) 8 Be(2α).…”

“…In this case, as it was before, the MPCM is used as a nuclear model, which allows one to consider some thermonuclear processes, notably, radiative capture reactions of neutrons and protons on light nuclei, on the basis of unified views, criteria and methods. [40][41][42][43] Continuing study of thermonuclear reactions in the frame of the MPCM with FSs 36 let us consider the 16 O(p,) 17 F process, which takes part of the CNO cycle 37 and has additional interest, since it is the reaction at the last nucleus of 1p-shell with the forming of 17 F that get out its limit. As we usually assume, 37,38 the bound state (BS) of 17 F is caused by the cluster channel of the initial particles, which take part in the reaction.…”

“…58 or Refs. 31,37,63,64 are written as:where  -total radiative capture cross section;  -reduced mass of initial channel particles; q -wave number in initial channel; S 1 , S 2 -spins of particles in initial channel; K, J -wave number and momentum of -quantum in final channel; N -is the Е or М transitions of the J multipole ordered from the initial J i to the final J f nucleus state.The value Р J for electric orbital ЕJ(L) transitions has the form 31,37Here, S i , S f , L f , L i , J f , and J i -total spins, angular and total moments in initial (i) and final (f) channels; m 1 , m 2 , Z 1 , Z 2 -masses and charges of the particles in initial channel; I J -integral over WFs of initial  i and final  f states, as functions of cluster relative motion of n and 10 B particles with intercluster distance R. For consideration of the М1(S) magnetic transition, caused by the spin part of magnetic operator, 65 it is possible to obtain an expression 31,37 using the following: …”

New measurements and phase shift analysis of p 16 O elastic scattering at astrophysical energies

“…About 20 years ago in our previous work [1], we showed a possible way to describe lithium nuclei in the framework of the potential cluster model (PCM) [2,3]. This PCM takes into account forbidden states (FSs) [3,4] in intercluster potentials that we used in [5].…”

Radiative p 16O Capture at Astrophyiscal Energies

“…Previously, in [1] on the basis of the modified potential cluster model (MPCM) [2][3][4][5][6][7][8] the possibility of description the coulomb form-factors of lithium nuclei was shown. This model uses intercluster potentials obtained on the basis of the elastic scattering phase shifts [9], taking into account the presence of the forbidden states (FSs) in wave functions (WFs) of system [10,11].…”