C. A. García Canal

Factorization in Semi-Inclusive Polarized Deep Inelastic Scattering

We calculate and analyze the O(αs) one-particle inclusive cross section in polarized deep inelastic lepton-hadron scattering, using dimensional regularization and the HVBM prescription for γ5. We discuss the factorization of all the collinear singularities related to the process, particularly those that are absorbed in the redefinition of the spin-dependent analogue of the recently introduced fracture functions. This is done in the usual MS scheme and in another one, called MSp, which factorizes soft contributions and guarantees the axial current (non-) conservation properties.

Influence of the LPM effect and dielectric suppression on particle air showers

An analysis of the influence of the Landau-Migdal-Pomeranchuk (LPM) effect on the development of air showers initiated by astroparticles is presented. The theory of Migdal is studied and compared with other theoretical methods, particularly the Blankenbecler-Drell approach. By means of realistic computer simulations and using algorithms that emulate Migdals theory, including also the so-called dielectric suppression, we study the behavior of the relevant observables in the case of ultrahigh energy primaries. We find that the LPM effect can significantly modify the development of high energy electromagnetic showers in certain cases.

Spontaneous CP violation in an SU(3)L⊗U(1)Y electroweak model

Abstract We study the possibility of finding spontaneous CP violation within an SU(3) L ⊗U(1) Y > electroweak model. We show that the mechanism is allowed for a certain range of the Higgs potential parameters only when a scalar sextuplet is included to provide the lepton masses.

Monopolium: The Key to monopoles

Dirac showed that the existence of one magnetic pole in the universe could offer an explanation for the discrete nature of the electric charge. Magnetic poles appear naturally in most grand unified theories. Their discovery would be of the greatest importance for particle physics and cosmology. The intense experimental search carried out thus far has not met with success. Moreover, if the monopoles are very massive their production is outside the range of present day facilities. A way out of this impasse would be if the monopoles bind to form monopolium, a monopole–antimonopole bound state, which is so strongly bound that it has a relatively small mass. Under these circumstances it could be produced with present day facilities and the existence of monopoles could be indirectly proven. We study the feasibility of detecting monopolium in present and future accelerators.

Order-αs2 corrections to one-particle inclusive processes in DIS

We analyze the order-

Generalization of the Hellmann–Feynman theorem

\alpha_s^2

Exact solution of electrostatic problem for a system of parallel cylindrical conductors

QCD corrections to semi-inclusive deep inelastic scattering and present results for processes initiated by a gluon. We focus in the most singular pieces of these corrections in order to obtain the hitherto unknown NLO evolution kernels relevant for the non homogeneous QCD scale dependence of these cross sections, and to check explicitly factorization at this order. In so doing we discuss the prescription of overlapping singularities in more than one variable.

Testing hadronic interaction packages at cosmic ray energies

Abstract The well-known Hellmann–Feynman theorem of quantum mechanics connected with the derivative of the eigenvalues with respect to a parameter upon which the Hamiltonian depends, is generalized to include cases in which the domain of definition of the Hamiltonian of the system also depends on that parameter.

Neutron-proton mass difference and the ϱ-ω mixing

The problem of the calculation of the electric field distribution of a system of infinite parallel cylindrical conductors in the presence of a grounded plane is reexamined. The exact solution of a class of two‐dimensional harmonic problems in multiply connected domains proposed by Burnside in 1893 is reviewed. This is shown to agree with recent generalizations of the method of images. An improved version of the exact solution which is more convergent than the conventional methods when the conductors are very close to one another is presented. The potential usefulness of the theoretical ideas and the mathematical apparatus used here for technological applications is emphasized.

Phase diagram of the ANNNI model in the Hamiltonian limit

A comparative analysis of the secondary particles output of the main hadronic interaction packages used in simulations of extensive air showers is presented. Special attention is given to the study of events with very energetic leading secondary particles, including diffractive interactions.