相关论文: On the higher-loop effective action in NJL model

A generalization to any dimension of the fermion field transformation which allows to derive the solution of the massless Schwinger model in the path integral framework is identified. New arguments based on this transformation for a…

The influence of mesonic fluctuations on quantities in the Nambu-Jona-Lasinio model is examined in different approximation schemes: an expansion in powers of 1/N_c and an expansion up to one-meson loop in the effective action formalism. It…

The contributions of non-standard four-neutrino contact interactions to electroweak observables are considered at the one-loop level by using the effective quantum field theory. The analysis is done in terms of three unknown parameters: the…

The process e+ e- -> 3 jets offers the opportunity to measure the strong coupling constant. For an accurate determination, precise theoretical calculations are necessary. I will give an overview on the status of the next-to-next-to-leading…

We study the solutions of the gap equation, the thermodynamic potential and the chiral susceptibility in and beyond the chiral limit at finite chemical potential in the Nambu--Jona-Lasinio (NJL) model. We give an explicit relation between…

In this work we compute the contributions to the Higgs effective potential coming from the fermion and gauge boson sectors at the one-loop level in the context of the SU(5)/SO(5) Littlest Higgs (LH) model using a cutoff Lambda and including…

In this work we study the $3+1$-dimensional Nambu-Jona-Lasinio (NJL) model in the mean field-approximation. We carry out calculations using five different regularization schemes (two continuum and three lattice regularization schemes) with…

We present results of numerical simulations of the 3+1 dimensional Nambu - Jona-Lasinio (NJL) model with a non-zero baryon density enforced via the introduction of a chemical potential mu not equal to 0. The triviality of the model with a…

The first one-loop higher-derivative contribution to the effective action of the Lorentz-breaking spinor QED is obtained and shown to be finite and ambiguous.

Three well-known perturbative approaches to deriving low-energy effective theories, the degenerate Brillouin-Wigner perturbation theory (projection method), the canonical transformation, and the resolvent methods are compared. We use the…

To study the high energy nuclear physics and the associated phenomenon, as the QGP/hadronic matter phase transition, the Nambu and Jona-Lasinio model (NJL) appears as an interesting alternative to the Quantum Chromodynamics, which is not…

We consider six-dimensional higher-derivative ${\cal N}=(1,0)$ supersymmetric gauge theory coupled with the hypermultiplet. We use the background superfield method in six-dimensional ${\cal N}=(1,0)$ harmonic superspace to study the…

The one-loop contribution to the superpotential, in particular the Veneziano-Yankielowicz potential in N=1 supersymmetric Yang-Mills model is discussed from an elementary field theory method and the matrix model point of view. Both…

We show how the resummation of large logarithms can be incorporated into the method of effective charges. As an example, we apply this approach to the event shape variables thrust and heavy jet mass in e+e- annihilation. We find that,…

A detailed description of the method for analytical evaluation of the three-loop contributions to renormalization group functions is presented. This method is employed to calculate the charge renormalization function and anomalous…

We calculate the three-loop contribution to the chiral effective potential in the massless Wess-Zumino model. It is shown that while the non-renormalisation theorem forbids divergent contributions to the chiral potential, in the massless…

We develop the superfield approach to the effective potential in three dimensions and calculate the one-loop and two-loop k\"{a}hlerian effective potential in commutative and noncommutative cases.

In this note we consider higher-loop contributions to the planar dilatation operator of N=4 SYM in the su(2) subsector of two complex scalar fields. We investigate the constraints on the form of this object due to interactions of two…

The decay width of the process eta -> pi^0 gamma gamma is calculated in the framework of the Nambu-Jona-Lasinio model. The momentum dependence of quark loops is taken into account. Three types of diagrams are considered: quark box,…

The problem of the higher-loop contributions to the axial anomaly is reexamined by a new method. We demonstrate that these contributions depend on the order of the calculations. If the divergence of the axial current by nonperturbative…