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Register a new userSurprising phenomenology in the non-Universal U(1) gauge extended $mu u$SSM
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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.
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Searches for new leptophobic resonances at high energy colliders usually target their decay modes into pairs of light quarks, top quarks, or standard model bosons. Additional decay modes may also be present, producing signatures to which current searches are not sensitive. We investigate the performance of generic searches that look for resonances decaying into two large-radius jets. As benchmark for our analysis we use a supersymmetric $text{U}(1)$ extension of the Standard Model, the so-called U$mu u$SSM, where all the SM decay modes of the $Z$ boson take place, plus additional (cascade) decays into new scalars. The generic searches use a generic multi-pronged jet tagger and take advantage of the presence of $b$ quarks in the large-radius jets, and are sensitive to all these $Z$ decay modes (except into light quarks) at once. For couplings that are well below current experimental constraints, these generic searches are sensitive at the $3sigma-4sigma$ level with Run 2 LHC data.
A non-universal $U(1)_{X}$ extension to the Standard Model composed of two scalar doublets and two scalar singlets together with three additional quark singlets and two lepton singlets and three generations of right-handed and Majorana neutrinos is made to explain lepton mass hierarchy, neutrino masses via inverse seesaw mechanism and muon anomalous magnetic moment in an anomaly free framework. In the present model, exotic and Standard Model particles acquire mass thanks to vacuum expectation values at different scales, yet the electron and the lightest neutrino are tree level massless but massive at one-loop level. By considering a numerical exploration and under the constraint of the Higgs mass, neutrino mass differences and PMNS matrix, it is found that only contributions due to exotic neutrinos interacting with charged scalars are relevant to muon $g-2$, though they are negative. Thus, the SUSY extension is considered and it is found that muon $g-2$ can be explained by allowing $U(1)_{X}$ vacuum expectation values to lie in the TeV scale thanks to SUSY soft-breaking interactions for at least $sim 10^{5}$ GeV masses. Thus, the contribution due to exotic neutrinos interacting with $W$ gauge bosons is positive and no longer negligible which added to all other contributions might explain the anomaly.
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.
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.
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.
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