Effects of different types of fields to cosmology and of extra dimension to fcnc hadronic processes of the sm

The Effects of Different Types of Fields to Cosmology. Alternative cosmological models are proposed as a harbinger of new physics to overcome the perceived shortcomings of the standard theory of cosmology (¤CDM). We consider a non-minimallycoupled massive complex scalar field to the curvature in the Jordan-Brans-Dicke (JBD)framework. We obtain an extra term to the Friedmann equation and it fits to supernova observations with a slightly lesser chi-squared value compared to the ¤CDM. Weassign the vector field as the photon field in JBD theory, a small photon mass leads to the late time in°ation. The background electric potential of the photon permeatesthe universe and explains the weakness of the gravitational interaction by coupling tothe curvature, hence the smallness of the Hubble parameter is linked with the smallness of the photon mass. Another feature of our model is that the Planck mass isinterpreted as the electric potential of the photon field thatfills the universe.Effects of an Extra Dimension to Some Hadronic Processes of theSM. Although the SM of particle physics is in perfect consistency with all con¯rmed collider data andthe precision tests so far, it has some de¯ciencies such as scale hierarchy problem, etc. The compactified extra dimensions have been proposed to reduce the differencebetween the Planck mass scale and the strength of the electro-weak force. We analyzethe effects of a single universal extra dimension (UED) on some flavor changing neutral current (FCNC) decays of hadrons such as baryonic and the mesonic transitions. We calculate some physical quantities such as branching ratio, lepton forward-backward asymmetry, double lepton polarization asymmetriesand hadron polarizations in terms of the compactification scale of the extra dimension.Using the experimental data provided by the CDF Collaboration on the branchingratio of lambda decay channel and comparing with our theoretical prediction, we put a constraint on the lower limit of the compactification scale of extra dimension tobe 250 GeV . The results of UED show overall considerable deviations from those of the SM which can be considered as indications for the existence of extra dimensions which we should look for them at hadron colliders.