Alpha cluster structure in 19F
Nauruzbayev D.K.1,3, Nurmukhanbetova A.K.1 , Goldberg V.Z. 2
1 Energetic Cosmos Laboratory,Nazarbayev University, Nur-Sultan, 010000,Kazakhstan,
2 Cyclotron Institute, Texas A&M University, College Station, Texas, USA
3 Saint Petersburg State University, Saint Petersburg, Russia
The nucleosynthesis of 19F was investigated over the past several years 1. The synthesis of fluorine occurs by 14N(α,γ)18F(β+)18O(p, α)15N(α,γ)19F reaction chain in the asymptotic giant branch stars [1-2]. For that reason, the studies of the abundance of 19F can be useful as a probe of stellar nucleosynthesis [1,3].
Several experimental groups also have been studied the properties of levels in 19F nuclei [1,4,5]. The aim of these studies was the knowledge of cluster structure in N>Z nuclei. Still, the information on the alpha cluster structure of 19F is scarce because of the experimental difficulties of the studies of elastic scattering of alpha particles at a gas target at low energy in the backward hemisphere .
We made the measurements of the 15N+α elastic scattering using the Thick Target Inverse Kinematic  method in a broad angular range including 180 degrees in c.m.s. at heavy ion accelerator DC-60 [7-8] (Nur-Sultan, Kazakhstan) and analyzed the available experimental data using R-matrix formalism . This study presents a comprehensive analysis of the experimental data and reveals an interesting relation between level structure in 19F and 20Ne.
Fig.1. demonstrates the quality of the new fit for θc.m. = 149.5  in the energy range 2.0-4.4 MeV.
Authors acknowledge financial support from the Nazarbayev University [small grant number 090118FD5346], the Ministry of Education and Science of the Republic of Kazakhstan [state-targeted program number BR05236454] and [young scientists’ research grant number AP08052268].Nauruzbayev D.K. is thankful for support from RFBR, research project No. 20-02-00295
1 M. La Cognata and et.al. Phys. Rev. C 99, 034301 (2019).
 A. Jorissen, V. V. Smith, and D. L. Lambert, Astron. Astrophys. 261, 164 (1992).
 M. Lugaro, C. Ugalde, A. I. Karakas, J. Görres, M. Wiescher,J. C. Lattanzio, and R. C. Cannon, Astrophys. J. 615, 934 (2004).
 H. Smotrich, K. W. Jones, L. C. McDermott, and R. E. Benenson, Phys. Rev. 122, 232 (1961).
 D. W. Bardayan, R. L. Kozub, and M. S. Smith.Phys. Rev. C 71, 018801(2005).
 K. P. Artemov and et.al. Yad. Fiz. 52, 634 (1990) [Sov. J. Nucl. Phys. 52, 408 (1990)].
 D. K. Nauruzbayev and et. al. Physical Review C 96, 014322 (2017)
 A.K. Nurmukhanbetova and et.al. Phys. Rev. C 100, 062802(R)
 Lane A. M. and Thomas R. G. Rev. Mod. Phys. 30 257,1958.