Undoubled Chiral Fermions on a Lattice

We analyze the dynamics of an $SU_L(2)\otimes U_R(1)$ chiral theory on the lattice with a strong multifermion coupling. It is shown that no spontaneous symmetry breaking occurs; the ``spectator'' fermion $\psi_R$ 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 and an undoubled left-handed chiral fermion remains in the continuum limit.Comment: Talk presented at LATTICE96 (chiral gauge), Late

Getting Around the Nielsen-Ninomiya Theorem, towards the Rome Approach

The ``no-go'' theorem of Nielsen and Ninomiya has been the most tenacious obstacle against the construction of a chiral gauge theory with reasonable low energy spectrum, couplings and anomaly. In this paper we construct a model which supplements the usual (bilinear in the Fermi fields) lagrangian with quadrilinear fermionic terms. We show that in a certain region of the parameter space the difficulties of the ``no-go'' theorem may be overcome, and a ``renormalized'' perturbative strategy can be carried out, akin to the one followed in the Rome Approach (RA), whose counterterms are forced to be gauge invariant.Comment: LaTex 12 pages, the version to appear in Phys. Lett.

Mass Relation Between Top and Bottom Quarks

In the framework of the recently proposed electroweak theory on a Planck lattice, we are able to solve approximately the lattice Dyson equation for the fermion self-energy functions, and obtain the ratio between the masses of the $t-$ and $b-$ quarks in terms of the electroweak coupling constants. The predicted top mass agrees with recent determinations from electroweak observables.Comment: To appear in Phys. Lett. B, 8 pages + 3 figure

A possible scaling region of chiral fermions on a lattice

We present the details of analyzing an $SU_L(2)\otimes U_R(1)$ chiral theory with multifermion couplings on a lattice. An existence of a possible scaling region in the phase space of multifermion couplings for defining the continuum limit of chiral fermions is advocated. In this scaling region, no spontaneous symmetry breaking occurs; the ``spectator'' fermion $\psi_R(x)$ is a free mode and decoupled; doublers are decoupled as massive Dirac fermions consistently with the $SU_L(2)\otimes U_R(1)$ chiral symmetry, whereas the normal mode of $\psi_L^i(x)$ is plausibly speculated to be chiral in the continuum limit. This is not in agreement with the general belief of the definite failure of theories so constructed.Comment: 32 pages, Latex and 5 figures, to appear in Nucl. Phys.

Nuclear halo and the coherent nuclear interaction

The unusual structure of Li11, the first halo nucleus found, is analyzed by the Preparata model of nuclear structure. By applying Coherent Nucleus Theory, we obtain an interaction potential for the halo-neutrons that rightly reproduces the fundamental state of the system.Comment: 9 pages Submitted to International Journal of Modern Physics E (IJMPE