arXiv subjects

Young-Ho Song

Publications and source records attributed to Young-Ho Song.

26 records · Page 2Linked to original sources

arXiv2011

Parity violation in low energy neutron deuteron scattering

Parity violating effects for low energy elastic neutron deuteron scattering are calculated for DDH and EFT-type of weak potentials in a Distorted Wave Born Approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The results of relation between physical observables and low energy constants can be used to fix low energy constants from experiments. Potential model dependencies of parity violating effects are discussed.

nucl-th↗

arXiv2010

Symmetry violations in few-body reactions: old and new approaches

As an attempt to find a way to resolve the discrepancy between calculated by traditional methods PV effects and the available set of experimental data, we analyze the methods of calculations of symmetry violating effects in few-body nuclear systems. The overview of methods of calculations of PV and TRIV effects in few-body neutron induced reactions is presented with the analysis of values of calculated parameters and their accuracy.

nucl-th↗

arXiv2010

Faddeev-type equations for three-body symmetry violating scattering amplitudes

The equations which relate three-body and two-body symmetry violating scattering amplitudes are derived in the first order of symmetry violating interactions. They can be used to obtain three-body symmetry violating scattering amplitudes from two-body symmetry violating scattering amplitudes calculated in low energy effective field theory.

nucl-th↗

arXiv2009

In-medium modification of P-wave charmonia from QCD sum rules

We investigate the changes of the masses and widths of $χ_{c0}$ and $χ_{c1}$ in hot gluonic matter near $T_c$ and in nuclear medium using QCD sum rules. As in the previous works for the $J/ψ$ and $η_c$, in-medium effects are incorporated through the changes of gluon condensates. Twist-2 terms for the $^3 P_0 (χ_{c0})$ and $^3 P_1 (χ_{c1})$ are also included for the first time. The results show that larger mass shifts and width broadenings take place as compared to the $S$-wave states. As the critical change take place near $T_c$, related measurements can reveal critical phenomenon in QCD.

hep-ph↗

arXiv2008

Up-to N$^3$LO heavy-baryon chiral perturbation theory calculation for the M1 properties of three-nucleon systems

M1 properties, comprising magnetic moments and radiative capture of thermal neutron observables, are studied in two- and three-nucleon systems. We utilize meson exchange current derived up to N$^3$LO using heavy baryon chiral perturbation theory a la Weinberg. Calculations have been performed for several qualitatively different realistic nuclear Hamiltonians, which permits us to analyze model dependence of our results. Our results are found to be strongly correlated with the effective range parameters such as binding energies and the scattering lengths. Taking into account such correlation, the results are in good agreement with the experimental data with small model-dependence.

nucl-th↗

arXiv2008

Effective field theory approach for the M1 properties of A=2 and 3 nuclei

The magnetic moments of ${}^2{H}$, ${}^3{He}$ and ${}^3{H}$ as well as the thermal neutron capture rate on the proton are calculated using heavy baryon chiral perturbation theory {\it à la} Weinberg. The M1 operators have been derived up to {N$^3$LO}. The nuclear matrix elements are evaluated with the use of wave functions obtained by carrying out variational Monte Carlo calculations for a realistic nuclear Hamiltonian involving high-precision phenomenological potentials like Argonne Av18 and Urbana IX tri-nucleon interactions. We discuss the potential- and cutoff-dependence of the results.

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arXiv2003

Hen Process in Effective Field Theory

An effective field theory technique that combines the standard nuclear physics approach and chiral perturbation theory is applied to the $hen$ process, ${}^{3}{He}+n\to {}^{4}{He}+ γ$. For the initial and final nuclear states, high-precision wave functions are generated via the variational Monte Carlo method using the Argonne $v_{14}$ potential and Urbana VIII trinucleon interactions, while the relevant transition operators are calculated up to ${\cal O}(Q^4)$ in HB$χ$PT. The imposition of the renormalization condition that the magnetic moments of ${}^{3}{He}$ and ${}^{3}{H}$ be reproduced allows us to carry out a parameter-free calculation of the $hen$ cross section. The result, $σ=(60\pm 3\pm 1) μb$, is in reasonable agreement with the experimental values, $(54\pm 6) μb$ and $(55\pm 3) μb$. This agreement demonstrates the validity of the calculational method previously used for estimating the reaction rate of the solar $hep$ process.

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arXiv2001

Meson Exchange Effect on Color Superconductivity

We investigate the effects of pion and gluon exchanges on the formation of two-flavor color superconductivity at moderate density, $μ<1 GeV$. The chiral quark model proposed by Manohar and Georgi containing pions as well as gluons is employed to show that the pion exchange reduces substantially the value of the superconducting gap gotten with the gluon exchange only. It turns out that the pion exchanges produce a repulsion between quark-quark pair in a spin and isospin singlet state. We suggest that the phase consisiting of pions, gluons and quarks is one of the candidates of in-medium QCD phase at moderate density.

hep-ph↗