Modern Physics Letters A

The neutrino emissivity from two- and three-flavor quark matter is numerically calculated and compared with Iwamoto’s formula. We find that the calculated emissivity is smaller than Iwamoto’s result by orders of magnitude when pf(u)+pf(e)−pf(d(s)) is comparable with the temperature. We attribute it to the severe restriction imposed by momentum conservation on the phase space integral. We obtain an alternative formula for the neutrino emissivity which is valid for any value of pf(u)+Pf(e)−Pf(d(s)) when the quarks and electrons are degenerate.

With the partial width for η→2γ determined by recent measurements in the process e⁺e⁻→e⁺e⁻η, we re-examine older data on the Primakoff effect. We show that photoproduction on nuclei can be used to determine the strength and the A-dependence of the coherent, isoscalar vector-meson field of the nuclei.

The coupling of elementary excitation modes in hot nuclei is studied. For this aim the quasiparticle-phonon nuclear model (QPM) is extended to a finite temperature by using the formalism of the thermofield dynamics. First the energies and structures of one-phonon states are calculated in the thermal random phase approximation and then the thermal QPM Hamiltonian H_QPM is expressed in terms of thermal quasiparticles and thermal RPA-phonons. The equation for the energies taking into account mixing of one-and two-thermal phonon states is derived. The expression of the coupling matrix element between thermal phonons is given.

A phenomenological theory of fermion masses and mixings is constructed within the framework of a four-family symmetry. It is found that the most favored set of relevant CKM elements are |V_us| ≈ 0.222, |V_cb| ≈ 0.044, |V_ub/V_cb| ≈ 0.082, |V_ud| ≈ 0.974, |V_cs| ≈0.9736, |V_cd| ≈ 0.224 with . The top quark mass is predicted to be 258 GeV at 1 GeV with its physical mass approximately in the range of 153 GeV to 165 GeV. Some remarks on the relationship between the lepton sector and the quark sector will be made.

We study the effect of dynamical gauge field on the Kaplan’s chiral fermion on a boundary in the strong gauge coupling limit in the extra dimension. To all orders of the hopping parameter expansion, we prove exact parity invariance of the fermion propagator on the boundary. This means that the chiral property of the boundary fermion, which seems to survive even in the presence of the gauge field from a perturbative point of view, is completely destroyed by the dynamics of the gauge field.

An alternative way to study the (2+1)-dimensional four-fermion model using the method of optimized expansions has been proposed. Contrary to Ref. 5 we use the technique of auxiliary scalar fields. In this the interpolation Lagrangian becomes nonlinear over the parameter ε. The effective potential has been constructed with the help of the canonical optimized procedure. A similar phase structure, as in the 1/N expansion, has been predicted. The β-function of the theory has been calculated in the framework of the optimized expansion method.

By employing the two-body relativistic equation as the starting point to calculate the spin-averaged spectrum of heavy quarkonium, we obtain a negative P-state energy difference ΔE_P=E(3P_cog)−E(¹P₁) of charmonium, which fits the data.

The infinite number of time-dependent linear in field and conjugated momenta invariants is derived for the scalar field using the Noether’s theorem procedure.

A simple property of the integrals over the hyperelliptic surfaces of arbitrary genus is observed. Namely, the derivatives of these integrals with respect to the branching points are given by the linear combination of the same integrals. We check that this property is responsible for the solution to the level zero Knizhnik-Zamolodchikov equation given in terms of hyperelliptic integrals.

We calculate the valence distribution of down quarks in the proton and up quarks in the neutron (the ‘minority’ quark distributions), taking into consideration the major sources of charge symmetry violation, including the effect of the mass difference of the u and d quarks on the bag wave function, and the masses of the intermediate diquark states. The relative difference of the distributions can be as large as 10% for intermediate values of Bjorken x.