55936188
Effect of time-odd mean fields on inertial parameters of the quadrupole collective Hamiltonian
Most current implementations of the quadrupole collective Hamiltonian model do not include the contributions of time-odd mean fields to the moments of inertia and mass parameters (Thouless-Valatin dynamical rearrangement contributions). A hybrid model is introduced that allows a quantitative estimate of these contributions to the inertial functions of a five- dimensional collective Hamiltonian based on microscopic energy density functionals. Fully self-consistent constrained relativistic Hartree-Bogoliubov calculations of triaxial energy surfaces in the β−γ plane are used to determine the parameters of an equivalent pairing-plus-quadrupole (P+Q) Hamiltonian. This Hamiltonian is employed in constrained Hartree-Fock- Bogoliubov (CHFB) plus local quasiparticle random-phase approximation (LQRPA) calculation of the deformation- dependent corrections to the Inglis-Belyaev moments of inertia and cranking mass parameters. This hybrid model is used to evaluate the influence of time-odd mean fields on vibrational and rotational collective masses and investigate their effect on the low-energy collective excitation spectra and transition rates of γ-soft Xe and Ba nuclei.
59391884
Efficient method for computing the Thouless-Valatin inertia parameters
Starting from the adiabatic time-dependent Hartree-Fock approximation (ATDHF), we propose an efficient method to calculate the Thouless-Valatin moments of inertia for the nuclear system. The method is based on the rapid convergence of the expansion of the inertia matrix. The accuracy of the proposed method is verified in the rotational case by comparing the results with the exact Thouless-Valatin moments of inertia calculated using the self-consistent cranking model. The proposed method is computationally much more efficient than the full ATDHF calculation, yet it retains a high accuracy of the order of 1%.
12610818
eta photoproduction of nucleons and the structure of the resonance S11(1535) in the quark model.
In this paper, we present our study on {eta} photoproduction based on the chiral quark model. We find that the quark model provides a very good description of {eta} production with far fewer parameters, and the threshold region is not a reliable source to determine the {eta}{ital NN} coupling constant due to its strong dependence on the properties of the resonance {ital S}{sub 11}(1535). We suggest that the systematic data in {ital E}{sub lab}=1.2--1.4 GeV region may help us to determine the {eta}{ital NN} coupling constant more precisely. The structure of the resonance {ital S}{sub 11}(1535) is discussed; we find that the recent data from Mainz group bring the helicity amplitude much closer to the quark model prediction. However, more studies need to be done to understand the large {eta}{ital N} branching ratio of the resonance {ital S}{sub 11}(1535). Our results show that the quark model is a very good approach to studying the underlying structure of baryon resonances from the meson photoproduction data.
18117055
Threshold pion photoproduction of nucleons in the chiral quark model.
In this paper, we show that the low energy theorem (LET) of threshold pion photoproduction can be fully recovered in the quark model. An essential result of this investigation is that the quark-pion operators are obtained from the effective chiral Lagrangian, and the low energy theorem does not require constraints on the internal structures of the nucleon. Changing from pseudovector to pseudoscalar quark-pion couplings generates an additional term at order [mu]=[ital m][sub [pi]]/[ital M] only in the isospin amplitude [ital A][sup ([minus])]. The role of the transitions between the nucleon and the resonance [ital P][sub 33](1232) or [ital P]-wave baryons is also discussed; we find that the leading contributions to the isospin amplitudes at [ital O]([mu][sup 2]) are from the transition between the [ital P]-wave baryons and the nucleon, and from the charge radius of the nucleon. The leading contribution from the [ital P]-wave baryons only affects neutral pion production, and improves the agreement with data significantly. The transition between the resonance [ital P][sub 33](1232) and the nucleon only gives an order [mu][sup 3] correction to [ital A][sup ([minus])].
59931380
Relativistic energy density functionals: Low-energy collective states ofPu240andEr166
The empirical relativistic density-dependent, point-coupling energy density functional, adjusted exclusively to experimental binding energies of a large set of deformed nuclei with A ≈ 150-180 and A ≈ 230-250, is tested with spectroscopic data for 166 Er and 240 Pu. Starting from constrained self-consistent triaxial relativistic Hartree-Bogoliubov calculations of binding energy maps as functions of the quadrupole deformation in the β-γ plane, excitation spectra and E2 transition probabilities are calculated as solutions of the corresponding microscopic collective Hamiltonian in five dimensions for quadrupole vibrational and rotational degrees of freedom and compared with available data on low-energy collective states.
15089471
Gauge invariant electromagnetic two-point function for heavy-light quark systems.
A gauge invariant electromagnetic two-point function, crucial to the investigations of the violation of isospin symmetry, is derived for heavy-light quark systems. Thus QED can be consistently introduced into the QCD sum rule method, which was not previously possible.
119587623
Consistent nucleon-nucleon potentials and three-body forces
We construct microscopic three-nucleon forces consistent with the Bonn and Nijmegen two-nucleon potentials, and including \ensuremath{\Delta}, Roper, and nucleon-antinucleon excitations. Recent results for the choice of the meson parameters are discussed. The forces are used in Brueckner calculations and the saturation properties of nuclear matter are determined.
120148837
CT10 next-to-next-to-leading order global analysis of QCD
We present next-to-next-to-leading order (NNLO) parton distribution functions (PDFs) from the CTEQ-TEA group. The CT10NNLO PDF fit is based on essentially the same global data sets used in the CT10 and CT10W NLO PDF analyses. After exploring the goodness of the fits to the HERA combined data and the Tevatron jet data, we present various predictions at NNLO accuracy for both existing and forthcoming precision measurements from the CERN Large Hadron Collider. The range of variations in the gluon distribution introduced by correlated systematic effects in inclusive jet production is also examined.
124926981
Analysis of Collective Flow in High Energy Heavy-Ion Collisions in the Relativistic VUU Approach
We have calculated the collective flow for collisions of by using the relativistic Vlasov-Uehling-Uhlenbeck (VUU) equation based on the QHD-I model of Walecka. The tensitivity of flow characterized by and to mean field and in-medium NN scattering cross section is studied. It is found that the azimuthal correlation function is reduced dramatically after inserting the collision term and then varies very slowly between NN cross sections from to and reaches the minimum at , while the in-plane mean transverse momentum increases slowly all the way from to . The collective flow is very sensitive to the momentum dependence (indicated by the effective mass ) of the mean field and less sensitive to the compression modulus K and the cross sections from to . The numerical results were compared with the experimental data, and we found that the agreement for both and can be reached with the same set of mean field parameters as well as the appropriate NN cross section in collision terms.
117793791
Constraints on nucleon effective mass splitting with heavy ion collisions
Abstract A new version of the improved quantum molecular dynamics model has been developed to include standard Skyrme interactions. Four commonly used Skyrme parameter sets, SLy4, SkI2, SkM* and Gs are adopted in the transport model code to calculate the isospin diffusion observables as well as single and double ratios of transverse emitted nucleons. While isospin diffusion observables are sensitive to the symmetry energy term, they are not very sensitive to the nucleon effective mass splitting parameters in the interactions. Our calculations show that the high energy neutrons and protons and their ratios from reactions at different incident energies provide a robust observable to study the momentum dependence of the symmetry potential which leads to the effective mass splitting. However the sensitivity of effective mass splitting effect on the double n/p yield ratios decreases with increasing beam energy, even though high energy protons and neutrons are produced more abundantly at high beam energy. Our calculations show that the optimum incident energy to study nucleon effective masses is between 100–200 MeV per nucleon.
14803102
Strong couplings of heavy mesons to a light vector meson in QCD
We make a detailed analysis of the $BB\rho(DD\rho)$ and $B^*B\rho(D^{*}D\rho)$ strong couplings $g_{BB\rho}(g_{DD\rho})$ and $g_{B^*B\rho}(g_{D^{*}D\rho})$ using QCD light cone sum rules(LCSR). The existing some negligence is pointed out in the previous LCSR calculation on $g_{B^*B\rho} (g_{D^{\ast}D\rho}$) and an updated estimate is presented. Our findings can be used to understand the behavior of the $B,D \to \rho$ semileptonic form factors at large momentum transitions.