Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe strong first order electroweak phase transition in the $U(1)_X$SSM
120
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In the $U(1)_X$ extension of the minimal supersymmetric standard model, we study a two step phase transition for the universe. The first step happens at high temperature from origin to z coordinate axis. The second step is the electroweak phase transition(EWPT) with barrier between two minima, which is the first order EWPT. We study the condition for this type phase transition to occur. The strong first order EWPT is our expection, and with the supposed parameters the evolution of the universe is plotted by the figures.
rate research
Read More
The MSSM is extended to the $U(1)_X$SSM, whose local gauge group is $SU(3)_C times SU(2)_L times U(1)_Y times U(1)_X$. To obtain the $U(1)_X$SSM, we add the new superfields to the MSSM, namely: three Higgs singlets $hat{eta},~hat{bar{eta}},~hat{S}$ and right-handed neutrinos $hat{ u}_i$. It can give light neutrino tiny mass at the tree level through the seesaw mechanism. The study of the contribution of the two-loop diagrams to the MDM of muon under $U(1)_X$SSM provides the possibility for us to search for new physics. In the analytical calculation of the loop diagrams (one-loop and two-loop diagrams), the effective Lagrangian method is used to derive muon MDM. Here, the considered two-loop diagrams include Barr-Zee type diagrams and rainbow type two-loop diagrams, especially Z-Z rainbow two-loop diagram is taken into account. The obtained numerical results can reach $7.4times10^{-10}$, which can remedy the deviation between SM prediction and experimental data to some extent.
We analyze the electroweak phase transition at finite temperature in a model of gauge-Higgs unification where the fermion mass hierarchy including top quark mass, a viable electroweak symmetry breaking and an observed Higgs mass are successfully reproduced. To study the phase transition, we derive the general formula of the 1-loop effective potential at finite temperature by using the $zeta$ function regularization method. It is remarkable that the functions determining the Kaluza-Klein mass spectrum have only to be necessary in calculations. This potential can be applicable to any higher dimensional theory in flat space where one extra spatial dimension is compactified. Applying to our model of gauge-Higgs unification, the strong first phase transition compatible with 125 GeV Higgs mass is found to happen.
The new experiment data of muon g-2 is consistent with the previous data of Fermion lab, and the departure from SM prediction is about 4.2 $sigma$. It strengthens our faith in the new physics. $U(1)_X$SSM is the U(1) extension of the minimal supersymmetric standard model, where we study the electroweak corrections to the anomalous magnetic dipole moment of muon from the one loop diagrams and some two loop diagrams possessing important contributions. These two loop diagrams include Barr-Zee type, rainbow type and diamond type. The virtual supersymmetric particles in these two loop diagrams are chargino, scalar neutrino, neutralino, scalar lepton, which are supposed not very heavy to make relatively large corrections. We obtain the Wilson coefficients of the dimension 6 operators inducing the anomalous magnetic dipole moment of muon. The numerical results can reach $25times 10^{-10}$ and even larger.
The possibility of a strongly first-order electroweak phase transition is established in the minimal supersymmetric standard model with an extra $U(1)$, where a nontrivial CP violating phase is introduced in its Higgs sector. We find that there is a wide region in the parameter space of the model that allows the strongly first-order electroweak phase transition. The mass of stop quark need not be smaller than the top quark mass to ensure the first-order electroweak phase transition be strong. The effect of the CP violating phase upon the strength of the phase transition is discovered. The strength of the phase transition is reduced when the size of the CP violation is increased. For a given CP violating phase, we find that the model has a larger mass for the lightest Higgs boson when it has a stronger phase transition.
So far the most sophisticated experiments have shown no trace of new physics at the TeV scale. Consequently, new models with unexplored parameter regions are necessary to explain current results, re-examine the existing data, and propose new experiments. In this Letter, we present a modified version of the $mu u$SSM supersymmetric model where a non-Universal extra U(1) gauge symmetry is added in order to restore an effective R-parity that ensures proton stability. We show that anomalies equations cancel without having to add emph{any} exotic matter, restricting the charges of the fields under the extra symmetry to a discrete set of values. We find that it is the viability of the model through anomalies cancellation what defines the conditions in which fermions interact with dark matter candidates via the exchange of $Z$ bosons. The strict condition of universality violation means that LHC constraints for a $Z$ mass do not apply directly to our model, allowing for a yet undiscovered relatively light $Z$, as we discuss both in the phenomenological context and in its implications for possible flavour changing neutral currents. Moreover, we explore the possibility of isospin violating dark matter interactions; we observe that this interaction depends, surprisingly, on the Higgs charges under the new symmetry, both limiting the number of possible models and allowing to analyse indirect dark matter searches in the light of well defined, particular scenarios.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
