Nuclear Theory·nucl-th

Thursday·January 12, 2017

5 papers—3 primary·2 cross-listed

01
Applications of Nuclear Physics
Anna C. Hayes
Today the applications of nuclear physics span a very broad range of topics and fields. This review discusses a number of aspects of these applications, including selected topics and concepts in nuclear reactor physics, nuclear fusion, nuclear non-proliferation, nuclear-geophysics, and nuclear medicine. The review begins with a historic summary of the early years in applied nuclear physics, with an emphasis on the huge developments that took place around the time of World War II, and that underlie the physics involved in designs of nuclear explosions, controlled nuclear energy, and nuclear fusion. The review then moves to focus on modern applications of these concepts, including the basic concepts and diagnostics developed for the forensics of nuclear explosions, the nuclear diagnostics at the National Ignition Facility, nuclear reactor safeguards, and the detection of nuclear material production and trafficking. The review also summarizes recent developments in nuclear geophysics and nuclear medicine. The nuclear geophysics areas discussed include geo-chronology, nuclear logging for industry, the Oklo reactor, and geo-neutrinos. The section on nuclear medicine summarizes the critical advances in nuclear imaging, including PET and SPECT imaging, targeted radionuclide therapy, and the nuclear physics of medical isotope production. Each subfield discussed requires a review article onto itself, which is not the intention of the current review. Rather, the current review is intended for readers who wish to get a broad understanding of applied nuclear physics.
nucl-thnucl-exRept.Prog.Phys.(2017)·11 citations
02
Reduced $E$ 1 $S$ -factor of $^{12}$ C( $α$ , $γ_{0}$ ) $^{16}$ O
M. Katsuma
The astrophysical $S$ -factor of $E$ 1 transition for $^{12}$ C( $α$ , $γ_{0}$ ) $^{16}$ O is discussed in the $R$ -matrix theory. The reduced $α$ -particle widths of the 1 $_{1}^{-}$ ( $E_{x} = 7.12$ MeV) and 1 $_{2}^{-}$ ( $E_{x} = 9.59$ MeV) states are extracted from the result of the potential model. The formal parameters are obtained without the linear approximation to the shift function. The resultant $E$ 1 $S$ -factor is not strongly enhanced by the subthreshold 1 $_{1}^{-}$ state if the channel radius is 4.75 fm. The calculated $β$ -delayed $α$ -particle spectrum of $^{16}$ N and the $p$ -wave phase shift of $α$ + $^{12}$ C elastic scattering are also found to be consistent with the previous studies. The small channel radius leads to the low penetrability to the Coulomb barrier, and it makes the reduced $E$ 1 $S$ -factor below the barrier. Owing to the large reduced width from the molecular structure, the $R$ -matrix pole of the 1 $_{2}^{-}$ state is shifted in the vicinity of 1 $_{1}^{-}$ . The proximity of the two poles suppresses the interference between the states. The transparency of the $α$ + $^{12}$ C system appears to be expressed as the shrinking strong interaction region.
nucl-thastro-ph.SRnucl-ex2 citations
03
On the microscopic structure of $π N N$ , $π N Δ$ and $π ΔΔ$ vertices
Ju-Hyun Jung🇦🇹 · Wolfgang Schweiger🇦🇹
We use a hybrid constituent-quark model for the microscopic description of $π N N$ , $π N Δ$ and $π ΔΔ$ vertices. In this model quarks are confined by an instantaneous potential and are allowed to emit and absorb a pion, which is also treated as dynamical degree of freedom. The point form of relativistic quantum mechanics is employed to achieve a relativistically invariant description of this system. Starting with an $S U (6)$ spin-flavor symmetric wave function for $N_{0}$ and $Δ_{0}$ , i.e. the eigenstates of the pure confinement problem, we calculate the strength of the $π N_{0} N_{0}$ , $π N_{0} Δ_{0}$ and $π Δ_{0} Δ_{0}$ couplings and the corresponding vertex form factors. Interestingly the ratios of the resulting couplings resemble strongly those needed in purely hadronic coupled-channel models, but deviate significantly from the ratios following from SU(6) spin-flavor symmetry in the non-relativistic constituent-quark model.
nucl-thFew Body Syst.(2017)·3 citations
04
Consequences of a strong phase transition in the dense matter equation of state for the rotational evolution of neutron stars
M. Bejger · D. Blaschke · P. Haensel · J. L. Zdunik · M. Fortin
We explore the implications of a strong first-order phase transition region in the dense matter equation of state in the interiors of rotating neutron stars, and the resulting creation of two disjoint families of neutron-star configurations (the so-called high-mass twins). We numerically obtained rotating, axisymmetric, and stationary stellar configurations in the framework of general relativity, and studied their global parameters and stability. The instability induced by the equation of state divides stable neutron star configurations into two disjoint families: neutron stars (second family) and hybrid stars (third family), with an overlapping region in mass, the high-mass twin-star region. These two regions are divided by an instability strip. Its existence has interesting astrophysical consequences for rotating neutron stars. We note that it provides a natural explanation for the rotational frequency cutoff in the observed distribution of neutron star spins, and for the apparent lack of back-bending in pulsar timing. It also straightforwardly enables a substantial energy release in a mini-collapse to another neutron-star configuration (core quake), or to a black hole.
↳ astro-ph.HEastro-ph.SRhep-phnucl-thAstron.Astrophys.(2017)·48 citations
05
Lattice Generalized Parton Distributions and Form Factors of the Nucleon
Martha Constantinou🇺🇸
In these proceedings we discuss recent progress in nucleon structure using lattice QCD simulations at or near the physical value of the pion mass. Main focus will be given in observables such as the nucleon axial charge and the first moments of parton distributions, for both the valence and sea quark contributions, and discuss their implications on the spin content of the nucleon. We will will also report developments on the evaluation of the gluon momentum fraction, which contributes significantly to the nucleon spin.
↳ hep-lathep-phnucl-th2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Applications of Nuclear Physics

Reduced E1 S-factor of 12C(α,γ0​)16O

On the microscopic structure of πNN, πNΔ and πΔΔ vertices

Consequences of a strong phase transition in the dense matter equation of state for the rotational evolution of neutron stars

Lattice Generalized Parton Distributions and Form Factors of the Nucleon

Affiliations

Reduced $E$ 1 $S$ -factor of $^{12}$ C( $α$ , $γ_{0}$ ) $^{16}$ O

On the microscopic structure of $π N N$ , $π N Δ$ and $π ΔΔ$ vertices