Related papers: Gauged $U(1)$ Clockwork
High-energy particle physics experiments allow for the possible existence of a new light, very weakly coupled, neutral gauge boson (the U boson). This one permits for light (spin-1/2 or spin-0) particles to be acceptable Dark Matter…
In these lectures, I discuss the role of symmetries in particle physics. I begin by discussing global symmetries and show that they can be realized differently in nature, depending on whether or not the vacuum state is left invariant by the…
We propose a new solution to the strong-CP problem. It involves the existence of an unbroken gauged $U(1)_X$ symmetry whose gauge boson gets a Stuckelberg mass term by combining with a pseudoscalar field $\eta (x)$. The latter has…
We make a careful re-examination of the possibility that, in a U(1) extension of the Standard Model, the extra Z' boson may acquire a mass from a Stueckelberg-type scalar. The model, when all issues of theoretical consistency are taken into…
Unparticle physics from a hidden conformal sector can alter the evolution of the Standard Model (SM) gauge couplings via TeV scale threshold corrections. We discuss how this may lead to gauge coupling unification at M_{GUT}\approx 2 \times…
The little hierarchy between the GUT scale and the string scale may give us some hints that can be tested at the LHC. To achieve string-scale gauge coupling unification, we introduce additional vector-like particles. We require that these…
The gauged $U(1)_{L_{\mu}-L_{\tau}}$ model can provide for additional contributions to the muon anomalous magnetic moment by means of a loop involving the $Z^{\prime}$ gauge boson. However, the parameter space of such models is severely…
The implementation of seesaw mechanisms to give mass to neutrinos in the presence of an anomaly-free U(1)_X gauge symmetry is discussed in the context of minimal extensions of the standard model. It is shown that type-I and type-III seesaw…
Recently we proposed a natural scenario of grand unified theories with anomalous U(1)_A gauge symmetry, in which doublet-triplet splitting is realized in SO(10) unification using Dimopoulos-Wilczek mechanism and realistic quark and lepton…
The issue of gauge unification in the (non-supersymmetric) Standard Model is reinvestigated. It is found that with just an additional fourth generation of quarks and leptons, $SU(3) \otimes SU(2) \otimes U(1)$ gauge couplings converge to a…
Motivated by the observation of tiny neutrino mass can not be explained within the framework of Standard Model (SM), we consider extra gauge extended scenarios in which tiny neutrino masses are generated through seesaw mechanism. These…
I consider models with non-universal gaugino masses at the gauge coupling unification scale, taking into account the Higgs boson discovery. Viable regions of parameter space are mapped and studied in the case of non-universality following…
The string landscape suggests that the supersymmetry breaking scale can be high, and then the simplest low energy effective theory is the Standard Model (SM). We show that gauge coupling unification can be achieved at about 10^{16-17} GeV…
Supersymmetric gauge theories, in higher dimensions compactified in an orbifold, give a natural framework to unify the gauge bosons, Higgs fields and even the matter fields in a single multiplet of the unifying gauge symmetry. The extra…
We explore the possibility of unification of gauge couplings near the Planck scale in models of extended technicolor. We observe that models of the form G X SU(3)_c X SU(2)_L X U(1)_Y cannot be realized, due to the presence of massless…
A procedure for studying low energy neutrinos processes using hadronic physics ideas is proposed. We describe how the neutrino-neutrino interactions can be modelled using massive gauge theories. The mass of the gauge bosons is created by…
$U(1)_X$SSM is a non-universal Abelian extension of the Minimal Supersymmetric Standard Model (MSSM) and its local gauge group is extended to $SU(3)_C\times SU(2)_L \times U(1)_Y\times U(1)_X$. Based on the latest data of neutral meson…
We propose models for neutrino masses and mixing in the framework of low scale $U(1)_{L_\mu-L_\tau}$ gauge extension of the standard model. The models are designed to spontaneously break $U(1)_{L_\mu-L_\tau}$ so that the…
In models with a low quantum gravity scale, one might expect that all operators consistent with gauge symmetries are present in the low-energy effective theory. If this is the case, some mechanism must be present to adequately suppress…
The quartic gauge boson couplings in the ${SU(3)}_C \otimes {SU(3)}_L \otimes {U(1)}_N$ models are presented. We find that the couplings of four {\it differrent} gauge bosons may have unusual Lorentz structure and the couplings sastify the…