We present an intuitive picture of the chiral symmetry breaking in the NJL and Thirring models. For the current current interaction model with the massless fermion, the vacuum is realized with the chiral symmetry broken phase, and the fermion acquires the induced mass. With this finite fermion mass, we calculate the boson mass, and find that the boson is always massive, and there exists no Gold...

The massive Schwinger model may be analysed by a perturbation expansion in the fermion mass. However, the results of this mass perturbation theory are sensible only for sufficiently small fermion mass. By performing a renormal-ordering, we arrive at a chiral perturbation expansion where the expansion parameter remains small even for large fermion mass. We use this renormal-ordered chiral pertur...

In a vector-like extension of the minimal standard model with mirror fermions leptoquarks can be bound states of fermion-mirror-fermion pairs held together by a new strong interaction at the TeV scale. The small couplings of leptoquarks to light fermion pairs arise due to mixing. The large Q event excess at HERA and also the high ET jet excess at Tevatron can potentially be explained.

We bosonize the massive Thirring model in the path integral. The kinetic term of the bosonic theory is found by performing a finite chiral rotation of the Thirring fermion, while the potential is obtained by integrating out the fermion. The resulting bosonic theory is the sine–Gordon model, and thus we reproduce Coleman’s old results. We use a new parametric representation of the fermion propag...

Considering the quark mixing induced over-determination of fermion field Renormalization Constants in on-shell scheme, we propose a new scheme differs from usual ”Incoming fermion” scheme and ”Outcoming fermion” scheme, which satisfies all of the on-shell renormalization conditions, thus can be used in LSZ reduction formula without any deviation when we calculate S-matrix elements from correlat...

Property of charged fermion states is investigated in the quenched U(1) chiral Wilson-Yukawa model. Fitting the charged fermion propagator with a single hyperbolic cosine does not yield reliable results. On the other hand the behavior of the propagator including large lattice size dependence is well described by the large Wilson-Yukawa coupling expansion, providing strong evidence that no charg...

We analyze the dynamics of an SUL(2)⊗UR(1) chiral theory on the lattice with a strong multifermion coupling. It is shown that no spontaneous symmetry breaking occurs; the “spectator” fermion ψR is a free mode; doublers are decoupled as massive Dirac fermions consistently with the chiral symmetries. In 1+1 dimension, we show that the right-handed three-fermion state disappears at the threshold a...

We summarize our recent study [1] of the fermion spectrum in a fermion-scalar 2D model with a chiral U (1)L × U (1)R global symmetry. This model is obtained from a two-cutoff formulation of a 2D U (1) chiral gauge theory, in the limit of zero gauge coupling. The massless fermion spectrum found deep in the vortex phase is undoubled and chiral.