Related papers: Leptophobic Z' from Superstring Derived Models
The H1 and ZEUS collaborations have recently reported a significant excess of events at high $Q^2$ in positron-proton collisions. While there exists insufficient data to conclusively determine the origin of this excess, one possibility is…
In recent years, significant experimental indications that point towards Lepton Flavour Universality violating effects in B-decays, involving $b \to c \tau \nu$ and $b \to s \ell^+ \ell^-$ have been accumulated. A possible New Physics…
We study low energy implications of F-theory GUT models based on $SU(5)$ extended by a $U(1)'$ symmetry which couples non-universally to the three families of quarks and leptons. This gauge group arises naturally from the maximal…
The recently proposed dark left-right gauge model, with Z' and W_R bosons at the TeV scale, is shown to have a simple supersymmetric extension which is unifiable. Its one-loop gauge-coupling renormalization-group equations are shown to have…
We investigate the phenomenology of singlet scalar dark matter in a simple $\rm U(1)_{B-L}$ gauge extension of standard model, made anomaly free with four exotic fermions. The enriched scalar sector and the new gauge boson $Z^\prime$,…
Motivated by the $b\to s\ell^+\ell^-$ anomalies recently reported by the LHCb collaboration, I present a class of flavored U(1)' gauge extensions of the Standard Model that naturally accommodates them and possesses a rich phenomenology.…
We consider the U(1)$_X$ model, which can induce the flavor violating couplings through vectorlike fermions and address the observed rare $B$-meson decay anomalies. To be consistent with all the other observations, both the associated gauge…
We build a supersymmetric version with $SU(3)_C\otimes SU(2)_L\otimes U(1)_{Y^\prime}\otimes U(1)_{B-L}$ gauge symmetry, where $Y^\prime$ is a new charge and $B$ and $L$ are the usual baryonic and leptonic numbers. The model has three…
There are many models beyond the standard model predicting the existence of non-universal gauge bosons $Z^{\prime}$, which can give rise to very rich phenomena. We calculate the contributions of the non-universal gauge bosons $Z^{\prime}$,…
I discuss gauge coupling unification in a class of superstring standard--like models, which are derived in the free fermionic formulation. Recent calculations indicate that the superstring unification scale is at $O(10^{18}GeV)$ while the…
The evidence for Lepton Flavour Universality (LFU) violation in semileptonic $B$-decays has been rising over the past few years. Relying on generic effective field theory (EFT) results, it has been shown that models addressing the…
Local supersymmetry (SUSY) provides an attractive framework for the incorporation of gravity and unification of gauge interactions within Grand Unified Theories (GUTs). Its breakdown can lead to a variety of models with softly broken SUSY…
If the quarks or leptons are charged under a new $U(1)$ gauge symmetry, then besides a $Z'$ boson there must exist at least one new boson whose decay products include Standard Model particles. In the case of a minimal symmetry breaking…
It is shown that a chiral SU(2) model can break Lorentz symmetry spontaneously at the Lagrangian level when gauge bosons become massive. This model seems to propose the principles and conceptual foundations leading to a unified picture of…
We show that in supersymmetric models with gauged B-L symmetry, there is a new source for cosmological lepton asymmetry. The Higgs bosons responsible for B-L gauge symmetry breaking decay dominantly into right-handed sneutrinos \tilde{N}…
We present a model that extends the electroweak gauge symmetry of the Standard Model in a non-universal way to $SU(2)_{L}^{\prime}\times U(1)_X \times SU(2)_{L}^{q_3}\times SU(2)_R^{\ell_3}$. This symmetry is spontaneously broken to…
Lepton flavor violating processes are obtained from the mixing between ordinary leptons and vectorlike SU(2)_L doublet leptons which may originate in E_6. The effects of this lepton mixing are, however, suppressed naturally by the hierarchy…
The interpretation of the apparent unification of gauge couplings within supersymmetric theories depends on uncertainties induced through heavy particle thresholds. While in standard grand unified theories these effects can be estimated…
We discuss the breaking of $SO(3)$ down to finite family symmetries such as $A_4$, $S_4$ and $A_5$ using supersymmetric potentials for the first time. We analyse in detail the case of supersymmetric $A_4$ and its finite subgroups $Z_3$ and…
We construct extensions of the Standard Model in which the gauge symmetries and supersymmetry prevent the dangerously large effects that may potentially be induced in a supersymmetric standard model by Planck scale physics. These include…