28368514
Numerical computation of two-loop box diagrams with masses
Abstract A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass configurations. As an example, the computation of two-loop planar and non-planar box diagrams is shown. The results are confirmed by comparisons with other techniques, including the reduction method, and by a consistency check using the dispersion relation.
123615884
Automation of loop amplitudes in numerical approach
Abstract An automatic calculating system GRACE-L1 of one-loop Feynman amplitude is reviewed. This system can be applied to 2 to 2-body one-loop processes. A sample calculation of 2 to 3-body one-loop amplitudes is also presented.
119889560
The Perturbative QCD and the e+e- Single Particle Inclusive Reaction
122500053
A New Treatment of the Scaling Violation for Flavor Singlet Distribution Functions in QCD
In a previous paper (Ref. 1), hereafter, we call I) , Q 2 dependence for the parton distribution functions is extensively studied in the framework of Quantum Chromodynamics (QCD). In the paper I, "kernel function" method (method-2 of I) is proposed to calculate the Q 2 dependent parton distribution functions. This method is intended to obtain the exact solution of Altarelli-Parisi equations. 2 >3> The parton distribution functions f. (x, Q 2) in a hadron are*>
121009792
QCD and Radiative Correction in Deep Inelastic Scattering
54183358
Calculation of Single Top Quark Production in Electron-Positron Scattering
92983154
Ground-state properties of neutron-rich Mg isotopes
We analyze recently measured total reaction cross sections for ${}^{24--38}$Mg isotopes incident on ${}^{12}$C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics (AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of ${}^{24--38}$Mg are then deduced from the measured reaction cross sections by fine tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for ${}^{24--36}$Mg, but still considerably underestimate them for ${}^{37,38}$Mg. The large matter radii suggest that ${}^{37,38}$Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number ($N$) dependence of deformation parameter is predicted by AMD. Large deformation is seen from ${}^{31}$Mg with $N=19$ to a drip-line nucleus ${}^{40}$Mg with $N=28$, indicating that both the $N=20$ and 28 magicities disappear. $N$ dependence of neutron skin thickness is also predicted by AMD.
122124774
Non‐Abelian discrete symmetry for flavors
We present a mathematical short review on non-Abelian discrete groups that could be used as reference introduction to the actual flavor models proposed to account for the observed flavor structure of quarks and leptons. For the practical purpose of flavor model building, we present group-theoretical aspects of S3, S4, A4, D4, Δ(27) and Δ(54).
29682328
Precession mode on high-K configurations: non-collective axially-symmetric limit of wobbling motion
The precession mode, the rotational excitation built on the high-K isomeric state, in comparison with the recently identified wobbling mode has been studied. The random-phase-approximation (RPA) formalism, which has been developed for the nuclear wobbling motion, is invoked and the precession phonon is obtained by the non-collective axially symmetric limit of the formalism. The excitation energies and the electromagnetic properties of the precession bands in 178W are calculated, and it is found that the results of RPA calculations well correspond to those of the rotor model; the correspondence can be understood by an adiabatic approximation to the RPA phonon. As a by-product, it is also found that the problem of too small out-of-band B(E2) in our previous RPA wobbling calculations can be solved by a suitable choice of the triaxial deformation which corresponds to the one used in the rotor model.
12942853
Calculation of strongly-coupled rotational bands in terms of the tilted axis cranking model
Abstract Recently observed strongly-coupled rotational bands associated with the ν[505] 11 2 − quasiparticle state are studied by means of a microscopic tilted axis cranking (TAC) model. The results of calculation for the routhians and the B (M1)/ B (E2) ratios are investigated in the light of other existing models, i.e., the strong-coupling model and the conventional cranking model. It is demonstrated that only the TAC model can successfully reproduce these two observables at the same time. The reason of the success is clarified by making connections between these models.
121954152
The role of spin-orbit potential in nuclear prolate-shape dominance
Abstract It is confirmed, in terms of the Woods–Saxon–Strutinsky method, that the spin–orbit potential plays a decisive role in the predominance of prolate deformation, which has been a long standing problem in nuclear physics. It is originated from the combined effects of the spin–orbit coupling and the diffused surface of the potential, in agreement with the previous work based on a more schematic Nilsson–Strutinsky method. The degree of prolate-shape dominance exhibits an oscillatory behavior with respect to the strength of spin–orbit potential and, the prolate-shape dominance is realized at the proper strength of the spin–orbit potential together with the standard surface diffuseness; this oscillatory behavior disappears in case of small diffuseness corresponding to ellipsoidal cavity. The calculated energy differences between oblate and prolate minima in this Letter are consistent with those of our extensive self-consistent calculations of the Hartree–Fock + BCS method with the Skyrme interaction.