15520096
Magnetic moment of the pentaquark Theta+(1540) with QCD sum rules
In this paper, we study the magnetic moment of the pentaquark state Θ+(1540) with the QCD sum rules approach in the external electromagnetic field. The numerical results indicate that the magnetic moment of the pentaquark state Θ+(1540) is about .
255344
Scalar form-factor of the proton with light-cone QCD sum rules
We calculate the scalar form factor of the proton in the framework of the light-cone QCD sum rules approach with the three valence quark light-cone distribution amplitudes up to twist-6 and observe the scalar form factor {sigma}(t=-Q{sup 2}) at intermediate and large momentum transfers Q{sup 2}>2 GeV{sup 2} has significant contributions from the end point (or soft) terms. The numerical values for the {sigma}(t=-Q{sup 2}) are compatible with the calculations from the chiral quark model and lattice QCD at the region Q{sup 2}>2 GeV{sup 2}.
14352659
The new extended left–right symmetric grand unified model with SO(3) family symmetry
Abstract We suggest a new left–right symmetric grand unified model by extending Pati–Salam group to contain an isospin SU ( 2 ) and a flavor SO ( 3 ) subgroup, where the superheavy fermions are introduced as a mirror to the low-energy standard model fermions. The model undergoes three steps to break to the SM by means of the specified Higgs multiplets. The model few parameters can elegantly accommodate whole mass spectra for all the particles at the electroweak scale, especially, two different flavor mixing for the quark and lepton sectors are reproduced in agreement with the current experimental data very well. The strong CP violation is excellently explained. The matter–antimatter asymmetry in the universe is successfully implemented through the B − L violating decays of the superheavy gauge bosons. The model also predicts that the lightest right-handed Majorana neutrino, whose mass is about several hundred GeVs and energy is about 10 16 GeV, is possibly a candidate for the dark matter.
119409718
Decay constants of the pseudoscalar mesons in the framework of the coupled Schwinger–Dyson equation and Bethe–Salpeter equation
Abstract In this article, we investigate the structures of the pseudoscalar mesons ( π , K , D , D s , B and B s ) in the framework of the coupled rainbow Schwinger–Dyson equation and ladder Bethe–Salpeter equation with the confining effective potential (infrared modified flat bottom potential). The Schwinger–Dyson functions for the u , d and s quarks are greatly renormalized at small momentum region and the curves are steep at about q 2 = 1 GeV 2 which indicates an explicitly dynamical symmetry breaking. The Euclidean time Fourier transformed quark propagators have no mass poles in the time-like region which naturally implements confinement. As for the c and b quarks, the current masses are very large, the renormalization are more tender, however, mass poles in the time-like region are also absent. The Bethe–Salpeter wavefunctions for those mesons have the same type (Gaussian type) momentum dependence and center around small momentum which indicate that the bound states exist in the infrared region. The decay constants for those pseudoscalar mesons are compatible with the values of experimental extractions and theoretical calculations, such as lattice simulations and QCD sum rules.
14097903
Magnetic moment of the pentaquark Θ+(1540) as diquark-diquark-antiquark state with QCD sum rules
Abstract.In this article, we study the magnetic moment of the pentaquark state Θ+(1540) as a diquark-diquark-antiquark ($[ud][ud]\bar{s}$) state with the QCD sum rules in an external weak electromagnetic field (EFSR) and the light-cone QCD sum rules (LCSR) respectively. The numerical results indicate that the magnetic moment is about $\mu_{\Theta^ + } = -(0.11\pm 0.02)\mu_N$ for the EFSR and $\mu_{\Theta^ + }\approx-(0.1$-$0.5)\mu_N$ for the LCSR. As the values obtained from the EFSR are more stable than the corresponding ones from the LCSR, $\mu_{\Theta^ + } = -(0.11\pm 0.02)\mu_N$ is more reliable.
16260034
Axial form-factor and induced pseudoscalar form-factor of the nucleons
We calculate the axial and the induced pseudoscalar form-factors GA(t=-Q2) and GP(t=-Q2) of the nucleons in the framework of the light-cone QCD sum-rules approach up to twist-6 three valence quark light-cone distribution amplitudes, and observe that the form-factors GA(t=-Q2) and GP(t=-Q2) at intermediate and large momentum transfers with Q2>2 GeV2 have significant contributions from the end-point (soft) terms. The numerical values for the axial form-factor GA(t=-Q2) are compatible with the experimental data and theoretical calculations; for example, the chiral quark models and lattice QCD. The numerical values for the induced pseudoscalar form-factor GP(t=-Q2) are compatible with the calculation from the Bethe–Salpeter equation.
119577104
Exact solution of the one-dimensional Hubbard model with arbitrary boundary magnetic fields
The one-dimensional Hubbard model with arbitrary boundary magnetic fields is solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz in the charge sector, the second eigenvalue problem associated with the spin sector is constructed. It is shown that the second eigenvalue problem can be transformed into that of the inhomogeneous XXX spin chain with arbitrary boundary fields which can be solved via the off-diagonal Bethe ansatz method. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.
16109370
Exact solution of the XXZ Gaudin model with generic open boundaries
The XXZ Gaudin model with generic integrable boundaries specified by generic non-diagonal K-matrices is studied. The commuting families of Gaudin operators are diagonalized by the algebraic Bethe ansatz method. The eigenvalues and the corresponding Bethe ansatz equations are obtained. (C) 2004 Elsevier B.V. All rights reserved.
118821038
Completeness and Bethe root distribution of the spin-1/2 Heisenberg chain with arbitrary boundary fields
Recently, the XXX spin chain with arbitrary boundary fields was successfully solved [1] via the off-diagonal Bethe ansatz method [2]. The correctness and the completeness of this solution were numerically verified by Nepomechie for one choice of the parameterizations [3]. In this paper, we discuss further the completeness of another parameterization of the Bethe ansatz equations and its reduction to the parallel boundary field case. The numerical results show that when the relative angle between the boundary fields turns to zero, both the T-Q relations and the Bethe ansatz equations are reduced to the ones obtained by the conventional Bethe ansatz methods. This allows us to establish a one-to-one correspondence between the Bethe roots of the unparallel boundary field case and those of the parallel boundary field case. In the thermodynamic limit, those two sets of Bethe roots tend to the same and the contribution of the relative angle to the energy is in the order of 1/N.
121376062
THE DRESSING TRANSFORMATION OF THE CONFORMAL AFFINE TODA
We study the dressing transformations of the conformal affine Todal which can be obtained from a Hamiltonian reduction. As a special case, we obtain the dressing transformations of the sinh-Gordon model. We will show that the dressing group is the semiclassical limit of the quantum group . We will also obtain the algebra of the charges which generate the infinitesimal dressing transformations.
118726735
Resonance phenomena and threshold features in positron—helium scattering
Investigations of resonances and threshold behaviors in positron—helium scattering have been made using the momentum-space coupled-channels optical method. The positronium formation channels are considered via an equivalent-local complex potential. The s-wave resonances and the Wigner cusp feature at the positronium (n = 1) formation threshold are compared with the previous reports. The p- and the d-wave resonances and a Wigner cusp feature at the positronium (n = 2) formation threshold are reported for the first time.