KHOA VẬT LÝ - VẬT LÝ KỸ THUẬT

BỘ MÔN VẬT LÝ HẠT NHÂN - KỸ THUẬT HẠT NHÂN

Nguyen Tri Toan Phuc, Kazuki Yoshida, Kazuyuki Ogatta,

Phys.Rev. C100,064604 - Published 6 December 2019

ABSTRACT:

Background: Proton-induced nucleon knockout (p,pN) reactions have been successfully used to study the single-particle nature of stable nuclei in normal kinematics with the distorted-wave impulse approximation (DWIA) framework. Recently, these reactions have been applied to rare-isotope beams at intermediate energies in inverse kinematics to study the quenching of spectroscopic factors.

Purpose: Our goal is to investigate the effects of various corrections and uncertainties within the standard DWIA formalism on the (p, pN) cross sections. The consistency of the extracted reduction factors between DWIA and other methods is also evaluated.
Method: We analyze the ( p, 2 p) and ( p, pn) reaction data measured at the R3 B-LAND setup at GSI for carbon, nitrogen, and oxygen isotopes in the incident energy range of 300–450 MeV/u. Cross sections and reduction factors are calculated by using the DWIA method. The transverse momentum distribution of the 12C(p,2p)11B reaction is also investigated.

Results: We have found that including the nonlocality corrections and the Møller factor affects the cross sections considerably. The proton-neutron asymmetry dependence of reduction factors extracted by the DWIA calculation is very weak and consistent with those given by other reaction methods and ab initio structure calculations.

Conclusions: The results found in this work provide a detailed investigation of the DWIA method for ( p, pN ) reactions at intermediate energies. They also suggest that some higher-order effects, which is essential for an accurate cross-section description at large recoil momentum, is missing in the current DWIA and other reaction models.

DOI: 10.1103/PhysRevC.100.064604

 Nguyen Tri Toan Phuc, R. S. Mackintosh, Nguyen Hoang Phuc, and Dao T. Khoa

Phys. Rev. C 100, 054615 – Published 18 November 2019

 ABSTRACT:

Background: A recent coupled-reaction-channel (CRC) study shows that the enhanced oscillation of the elastic 16O+12C section at backward angles is due mainly to the elastic α transfer or the core exchange. Such a process gives rise to a parity-dependent term in the total elastic S matrix, an indication of the parity dependence of the 16O+12C optical potential (OP).

Purpose: To explicitly determine the core exchange potential (CEP) induced by the symmetric exchange of the two 12C cores in the elastic 16O+12C scattering at Elab=132 and 300 MeV and explore its parity dependence.

Method: S matrix generated by CRC description of the elastic 16O+12C scattering is used as the input for the inversion calculation to obtain the effective local OP that contains both the Wigner and Majorana terms.

Results: The high-precision inversion results show a strong contribution by the complex Majorana term in the total OP of the 16O+12C system and thus provide for the first time a direct estimation of the parity-dependent CEP.

Conclusions: The elastic α transfer or exchange of the two 12C cores in the 16O+12C system gives rise to a complex parity dependence of the total OP. This should be a general feature of the OP for the light heavy-ion systems that contain two identical cores.

 

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The Deep Underground Neutrino Experiment (DUNE) is an international research collaboration aimed at exploring topics related to neutrinos and proton decay, which should start collecting data around 2025. In a recent study featured in Physical Review Letters, a team of researchers at Ohio State University have showed that DUNE has the potential to deliver groundbreaking results and insight about solar neutrinos.

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Consistency test of coincidence-summing calculation methods for extended sources

O.Sima, A.De Vismes Ott, M.S.Dias, P.Dryak, L.Ferreux, D.Gurau,  S.Hurtado, P.Jodlowski, K.Karfopoulos, M.F.Koskinas, M.Laubenstein, Y.K.Lee, M.C.Lépy, A.Luca, M.O.Menezes, D.S.Moreira, J.Nikolič, V.Peyres, P.Saganowski, M.I.Savva, R.Semmler, J.Solc, T.T.Thanh, K.Tyminska, Z.Tyminski, T.Vidmar, I.Vukanac, H.Yucel

Abstract:

An internal consistency test of the calculation of coincidence-summing correction factors FC for volume sources is presented. The test is based on exact equations relating the values of FC calculated for three ideal measurement configurations. The test is applied to a number of 33 sets of FC values sent by 21 teams. Most sets passed the test, but not the results obtained using the quasi-point source approximation; in the latter case the test qualitatively indicated the magnitude of the bias of FC.

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Semiconductors are the basic building blocks of digital devices. Improvements in semiconductor functionality and performance are likewise enabling next-generation applications of semiconductors for computing, sensing and energy conversion. Yet researchers have long struggled with limitations in their ability to fully understand the electronic charges inside semiconductor devices and advanced semiconductor materials, limiting researchers' ability to drive further advances.

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 Mean-field description of heavy-ion scattering at low energies and fusion

Dao T. Khoa, Le Hoang Chien, Do Cong Cuong, Nguyen Hoang Phuc

Abstract:

The nuclear mean-field potential built up during the 12C + 12C and 16O + 16O collisions at low energies relevant for the carbon- and oxygen-burning processes is constructed within the double-folding model (DFM) using the realistic ground-state densities of 12C and 16O, and CDM3Yn density-dependent nucleon–nucleon (NN) inter- action. The rearrangement term, indicated by the Hugenholtz–van Hove theorem for the single-particle energy in nuclear matter, is properly considered in the DFM calculation. To validate the use of the density-dependent NN interaction at low energies, an adiabatic approximation was suggested for the dinuclear overlap density. The reliability of the nucleus–nucleus potential predicted through this low-energy version of the DFM was tested in the optical model (OM) analysis of the elastic 12 C + 12 C and 16 O + 16O scattering data at energies below 10 MeV/nucleon. These OM results provide a consistently good description of the elastic angular distributions and 90 excitation function. The dinuclear mean-field potential predicted by the DFM is further used to determine the astrophysical S factor of the 12C + 12C and 16O + 16O fusions in the barrier penetration model. Without any adjustment of the potential strength, our results reproduce the non-resonant behavior of the S factor of the 12C + 12C and 16O + 16O fusions very well over a wide range of energies.

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