Tensor interactions and τ\tau decays

We study the effects of charged tensor weak currents on the strangeness-changing decays of the $\tau$ lepton. First, we use the available information on the $K^+_{e3}$ form factors to obtain BR$(\tau^- \rightarrow K^-\pi^0 \nu_{\tau})\sim {\cal O}(10^{-4})$ when the $K\pi$ system is produced in an antisymmetric tensor configuration. Then, we propose a mechanism for the direct production of the $K_2^*(1430)$ in $\tau$ decays. Using the current upper limit on this decay we set a bound on the symmetric tensor interactions.Comment: 13 pages, Late

One-dimensional relativistic dissipative system with constant force and its quantization

For a relativistic particle under a constant force and a linear velocity dissipation force, a constant of motion is found. Problems are shown for getting the Hamiltoninan of this system. Thus, the quantization of this system is carried out through the constant of motion and using the quantization of the velocity variable. The dissipative relativistic quantum bouncer is outlined within this quantization approach.Comment: 11 pages, no figure

Adsorption of Self-Assembled Rigid Rods on Two-Dimensional Lattices

Monte Carlo (MC) simulations have been carried out to study the adsorption on square and triangular lattices of particles with two bonding sites that, by decreasing temperature or increasing density, polymerize reversibly into chains with a discrete number of allowed directions and, at the same time, undergo a continuous isotropic-nematic (IN) transition. The process has been monitored by following the behavior of the adsorption isotherms for different values of lateral interaction energy/temperature. The numerical data were compared with mean-field analytical predictions and exact functions for noninteracting and 1D systems. The obtained results revealed the existence of three adsorption regimes in temperature. (1) At high temperatures, above the critical one characterizing the IN transition at full coverage Tc(\theta=1), the particles are distributed at random on the surface and the adlayer behaves as a noninteracting 2D system. (2) At very low temperatures, the asymmetric monomers adsorb forming chains over almost the entire range of coverage, and the adsorption process behaves as a 1D problem. (3) In the intermediate regime, the system exhibits a mixed regime and the filling of the lattice proceeds according to two different processes. In the first stage, the monomers adsorb isotropically on the lattice until the IN transition occurs in the system and, from this point, particles adsorb forming chains so that the adlayer behaves as a 1D fluid. The two adsorption processes are present in the adsorption isotherms, and a marked singularity can be observed that separates both regimes. Thus, the adsorption isotherms appear as sensitive quantities with respect to the IN phase transition, allowing us (i) to reproduce the phase diagram of the system for square lattices and (ii) to obtain an accurate determination of the phase diagram for triangular lattices.Comment: Langmuir, 201

One-Loop Electroweak Corrections to the Muon Anomalous Magnetic Moment Using the Pinch Technique

The definition of the physical properties of particles in perturbative gauge theories must satisfy gauge invariance as a requisite. The Pinch Technique provides a framework to define the electromagnetic form factors and the electromagnetic static properties of fundamental particles in a consistent and gauge-invariant form. We apply a simple prescription derived in this formalism to check the calculation of the gauge-invariant one-loop bosonic electroweak corrections to the muon anomalous magnetic moment.Comment: 6 pages and 1 eps figur

Velocity quantization approach of the one-dimensional dissipative harmonic oscillator

Given a constant of motion for the one-dimensional harmonic oscillator with linear dissipation in the velocity, the problem to get the Hamiltonian for this system is pointed out, and the quantization up to second order in the perturbation approach is used to determine the modification on the eigenvalues when dissipation is taken into consideration. This quantization is realized using the constant of motion instead of the Hamiltonian.Comment: 10 pages, 2 figure