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We study some perturbative and nonperturbative effects in the framework of the\ud Standard Model of particle physics. In particular we consider the time dependence\ud of the Higgs vacuum expectation value given by the dynamics of the StandardModel\ud and study the non-adiabatic production of both bosons and fermions,\ud which is intrinsically non-perturbative. In theHartree approximation, we analyze\ud the general expressions that describe the dissipative dynamics due to the backreaction\ud of the produced particles. Then, we solve numerically some relevant\ud cases for the Standard Model phenomenology in the regime of relatively small\ud oscillations of the Higgs vacuum expectation value (vev). As perturbative effects,\ud we consider the leading logarithmic resummation in small Bjorken x QCD, concentrating\ud ourselves on the Nc dependence of the Green functions associated to\ud reggeized gluons. Here the eigenvalues of the BKP kernel for states of more than\ud three reggeized gluons are unknown in general, contrary to the large Nc limit\ud (planar limit) case where the problem becomes integrable. In this contest we consider\ud a 4-gluon kernel for a finite number of colors and define some simple toy\ud models for the configuration space dynamics, which are directly solvable with\ud group theoretical methods. In particular we study the depencence of the spectrum\ud of thesemodelswith respect to the number of colors andmake comparisons\ud with the planar limit case. In the final part we move on the study of theories\ud beyond the Standard Model, considering models built on AdS5 S5/Γ orbifold\ud compactifications of the type IIB superstring, where Γ is the abelian group Zn.\ud We present an appealing three family N = 0 SUSY model with n = 7 for the order\ud of the orbifolding group. This result in a modified Pati–Salam Model which\ud reduced to the StandardModel after symmetry breaking and has interesting phenomenological\ud consequences for LHC

Topics:
FIS/02 Fisica teorica, modelli e metodi matematici

Year: 2008

DOI identifier: 10.6092/unibo

OAI identifier:
oai:amsdottorato.cib.unibo.it:844

Provided by:
AMS Tesi di Dottorato

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