123012350
Phenomenological study of Sudakov effects in the pion form factor
The pion electromagnetic form factor with leading and next-to-leading twist corrections is studied in the framework of the pQCD approach. We find that the Sudakov effects provide a weak suppression of the nonperturbative contributions at the experimental accessible energy region. We also find a large twist-3 contribution. Our conclusion is that the prediction of the pion form factor in the pQCD approach is not precise.
14014748
The reliability of pQCD approach in pion electromagnetic form factor
The pion electromagnetic form factor with leading and next-to-leading twist corrections are studied in the framework of pQCD approach. We find that, at small momentum transfer regions, Sudakov effects cannot provide a strong enough suppression of the non-perturbative contributions coming from large transverse separations, but at large momentum transfer region, non-perturbative contributions can be effectively suppressed. So pQCD approach can be applied at large momentum transfer region. At the energy region where experiment can access so far, i.e. Q < 4GeV, pQCD prediction can not be precise because there may be a quite large part of contributions coming from non-perturbative region. The calculation of power corrections may not be performed systematically in pQCD framework.
123415067
The soft-collinear effective theory and factorization
122357291
UNPARTICLE PHYSICS AND NEUTRAL MESON MIXING
The concept of exact and broken scale invariance is discussed. We give a brief introduction to unparticle physics. The neutral meson mixing can be caused by exchange of unparticle at the tree level. The constraints on interaction between unparticle and SM quarks are discussed.
116907310
A solution to Higgs naturalness
The Standard Model (SM) is usually considered to be unnatural because the scalar Higgs mass receives a quadratic divergent correction. We suggest a new way to solve the naturalness problem from point of view of renormalization group method. Our approach is illustrated through the familiar $\phi^4$ theory. A renormalization group equation for scalar field mass is proposed by introducing a subtraction scale. We give a non-trivial prediction: the Higss mass at short-distance is a damping exponential function of the energy scale. It follows from a characteristic of the SM that the couplings to Higgs are proportional to field masses, in particular the Higgs self-interactions. In the ultraviolent limit, the Higgs mass approaches to a mass called by Veltman mass which is at the order of the electroweak scale. The fine-tuning is not necessary. The Higgs naturalness problem is solved by radiative corrections themselves.
17002782
Inelastic final-state interactions in B → VV →π K processes

Abstract. We study the final-state interactions in B →π K decays through B → VV →π K processes where the inelastic rescattering occurs via single pion exchange. The next-to-leading order low-energy effective Hamiltonian and Bauer-Stech-Wirbel (BSW) model are used to evaluate the weak transition matrix elements and final-state interactions. We found that the final-state interaction effects in B →ρ K*→π K processes are significant. The Fleischer-Mannel relation for the Cabibbo-Kobayashi-Maskawa (CKM) angle γ can be significantly
modified.
122147995
Hyperon–hyperon interaction in relativistic mean field model
By using the new experimental data of �� potential, this paper has performed a full calculation for strange hadronic matter with different strangeness contents as well as its consequences on the global properties of neutron star matter in relativistic mean field model. It finds that the new weak hyperon–hyperon interaction makes the equations of state much stiffer than the result of the previous strong hyperon–hyperon interaction, and even stiffer than the result without consideration of hyperon–hyperon interaction. This new hyperon–hyperon interaction results in a maximum mass of 1.75M⊙ (where M⊙ stands for the mass of the Sun), about 0.2–0.5M⊙ larger than the previous prediction with the presence of hyperons. After examining carefully the onset densities of kaon condensation it finds that this new weak version of hyperon–hyperon interaction favours the occurrence of kaons in comparison with the strong one.
122313362
Hyperon coupling dependence of hadron matter properties in relativistic mean field model
The properties of hadronic matter at β equilibrium in a wide range of densities are described by appropriate equations of state in the framework of the relativistic mean field model. Strange meson fields, namely the scalar meson field σ* (975) and the vector meson field (1020), are included in the present work. We discuss and compare the results of the equation of state, nucleon effective mass, and strangeness fraction obtained by adopting the TM1, TMA, and GL parameter sets for nuclear sector and three different choices for the hyperon couplings. We find that the parameter set TM1 favours the onset of hyperons most, while at high densities the GL parameter set leads to the most hyperon-rich matter. For a certain parameter set (e.g. TM1), the most hyperon-rich matter is obtained for the hyperon potential model. The influence of the hyperon couplings on the effective mass of nucleon, is much weaker than that on the nucleon parameter set. The nonstrange mesons dominate essentially the global properties of dense hyperon matter. The hyperon potential model predicts the lowest value of the neutron star maximum mass of about 1.45 Msun to be 0.4-0.5 Msun lower than the prediction by using the other choices for hyperon couplings.
204011866
Effect of tensor force on the density dependence of symmetry energy within the BHF framework
The effect of tensor force on the density dependence of nuclear symmetry energy has been investigated within the framework of the Brueckner-Hartree-Fock (BHF) approach. It is shown that the tensor force manifests its effect via the tensor 3SD1 channel. The density dependence of symmetry energy Esym turns out to be determined essentially by the tensor force from the π meson and ρ meson exchanges via the 3SD1 coupled channel. Increasing the strength of the tensor component due to the ρ-meson exchange tends to enhance the repulsion of the equation of state of symmetric nuclear matter and leads to the reduction of symmetry energy. The present results confirm the dominant role played by the tensor force in determining nuclear symmetry energy and its density dependence within the microscopic BHF framework.
124556870
A New Effect in the QCD Fusion of Nuclear Partons
The parton fusion in nucleus at the leading order of recombination is investigated based on perturbative QCD. We compute various cut diagrams including the nuclear parton fusion, and find that the parton-fusion effects depend on the nuclear QCD structure.
119716730
A twist-4 effect in the parton evolution processes
Recently, a research group reported that they can fit the F2 data well by using the Altarelli-Parisi evolution equation with a valence-like initial gluon distribution, which means that we need not consider the high twist effects in the proton. In this letter, we point out that their valence-like initial gluon distribution is unreasonable for the proton structure function. With the reasonable initial distributions, we find that the high twist corrections to the Altarelli-Parisi evolution equation is necessary.