International Journal of Modern Physics A

Hadronic spectroscopy can be introduced to students and developed rather far without requiring SU(N) flavor symmetry. In such a "minimalist" presentation, we are naturally led to comment and clarify the concept of the "generalized" Pauli principle.

Recently a perturbative theory has been constructed, starting from the Feynman rules of the nonlinear sigma model at the tree level in the presence of an external vector source coupled to the flat connection and of a scalar source coupled to the nonlinear sigma model constraint (flat connection formalism). The construction is based on a local functional equation, which overcomes the problems due to the presence (already at one loop) of nonchiral symmetric divergences. The subtraction procedure of the divergences in the loop expansion is performed by means of minimal subtraction of properly normalized amplitudes in dimensional regularization. In this paper we complete the study of this subtraction procedure by giving the formal proof that it is symmetric to all orders in the loopwise expansion. We provide further arguments on the issue that, within our subtraction strategy, only two parameters can be consistently used as physical constants.

We have studied the dependence of the allowed space of the atmospheric neutrino oscillation parameters on the time of exposure for a magnetized Iron CALorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). We have performed a Monte Carlo simulation for a 50 kTon ICAL detector generating events by the neutrino generator NUANCE and simulating the detector response by GEANT. A chi-square analysis for the ratio of the up-going and down-going neutrinos as a function of L/E is performed and the allowed regions at 90% and 99% CL are displayed. These results are found to be better than the current experimental results of MINOS and Super-K. The possibilities of further improvement have also been discussed.

We consider the Darboux transformation of the Green functions of the regular boundary problem of the one-dimensional stationary Dirac equation. We obtained the Green functions of the transformed Dirac equation with the initial regular boundary conditions. We also obtain the formula for the full trace of the difference of the transformed and initial Green functions of the regular boundary problem of the one-dimensional stationary Dirac equation. We illustrate our findings by the consideration of the Darboux transformation of the Green function on an interval.

The efficiency of a pixel detector using optical UV filters is determined in this work. Based on the Auger fluorescence detector geometry, we have calculated the overall efficiency of the pixel detector using an appropriate method that takes into account the particular spectral functions and the dependence on the angle of incidence of the optical filter used. Assuming extensive air shower (EAS) events developed with various inclinations generated by AIRES code, we calculated the number of electrons and positrons produced during the development of the EAS's. The detection efficiency of the pixel detector is taken into account in estimating the recorded signal (number of photoelectrons) for two sets of EAS simulations, corresponding to protons and iron nuclei, as primary particles.

Based on the proposal that the Skyrme theory is a theory of monopole we provide a new interpretation of Skyrme theory, that the theory can also be viewed as an effective theory of strong interaction which is dual to QCD, where the monopoles (not the quarks) are confined through the Meissner effect. This dual picture leads us to predict the existence of a topological glueball in QCD, a chromoelectric knot which is dual to the chromomagnetic knot in Skyrme theory, whose mass and decay width are estimated to be around 60 GeV and 8 GeV. As importantly, the existence of the magnetic vortex and knot in Skyrme theory strongly indicates that the theory could also be interpreted to describe a very interesting low energy condensed matter physics in a completely different environment. These new interpretations of Skyrme theory puts the theory in a totally new perspective.

We show that Green function methods can be straightforwardly applied to nonlinear equations appearing as the leading order of a short time expansion. Higher-order corrections can be then computed giving a satisfactory agreement with numerical results. The relevance of these results relies on the possibility of fully exploiting a gradient expansion in both classical and quantum field theory granting the existence of a strong coupling expansion. Having a Green function in this regime in quantum field theory amounts to obtain the corresponding spectrum of the theory.

We investigate supergroups with Grassmann parameters replaced by odd Clifford parameters. The connection with nonanticommutative supersymmetry is discussed. A Berezin-like calculus for odd Clifford variables is introduced. Fermionic covariant derivatives for supergroups with odd Clifford variables are derived. Applications to supersymmetric quantum mechanics are made. Deformations of the original supersymmetric theories are encountered when the fermionic covariant derivatives do not obey the graded Leibniz property. The simplest nontrivial example is given by the N = 2 supersymmetric quantum mechanics with a real (1, 2, 1) multiplet and a cubic potential. The action is real. Depending on the overall sign ("Euclidean" or "Lorentzian") of the deformation, a Bender–Boettcher pseudo-Hermitian Hamiltonian is encountered when solving the equations of motions of the auxiliary field. A possible connection of our framework with the Drinfeld twist deformation of supersymmetry is pointed out.

Standard formulae of classical electromagnetism for the forces between electric charges in motion derived from retarded potentials are compared with those obtained from a recently developed relativistic classical electrodynamic theory with an instantaneous intercharge force. Problems discussed include small angle Rutherford scattering, Jackson's recent "torque paradox" and circular Keplerian orbits. Results consistent with special relativity are obtained only with an instantaneous interaction. The impossibility of stable circular motion with retarded fields in either classical electromagnetism or Newtonian gravitation is demonstrated.