Related papers: Resolving the A_{FB}^b puzzle in an extra dimensio…
By extending the standard gauge group to SU(3)_c \times SU(2)_L \times U(1)_Y \times U(1)_X with X charges carried only by the third family we accommodate the LEP measurement of R_b and predict a potentially measurable discrepancy in…
We study the potential effect of anomalous couplings of the third generation quarks to gauge bosons in rare B decays. We focus on the constraints from flavor changing neutral current processes such as $b\to s\gamma$ and $b\to s…
We consider an abelian extension of the Standard Model (SM) comprising a new gauge group $U(1)^\prime$, with the neutral gauge boson $Z^\prime$ having flavour violating couplings to quarks and leptons. The fermion content is the same as in…
The bottom quark forward-backward asymmetry ($A_{FB}^b$) data at LEP exhibits a long-standing discrepancy with the standard model prediction. We propose a novel method to probe the $Zb\bar{b}$ interactions through $gg\to Zh$ production at…
We compute the order $\alpha_s^2$ QCD corrections to the $b$-quark forward-backward asymmetry in $e^+e^-\to b{\bar b}$ collisions at the $Z$ boson resonance, taking the non-zero mass of the $b$ quark into account. We determine these…
We investigate the collider phenomenology of a left-right symmetric Randall-Sundrum model with fermions and gauge bosons in the bulk. We find that the model is allowed by precision electroweak data as long as the ratio of the (unwarped)…
The signals of the SO(5) \times U(1) gauge-Higgs unification model at the International Linear Collider are studied. In this model, Kaluza-Klein modes of the neutral gauge bosons affect fermion pair productions. The deviations of the…
We report the first measurement of the lepton forward-backward asymmetry ${\cal A}_{\rm FB}$ as a function of the squared four-momentum of the dilepton system, $q^2$, for the electroweak penguin process $B \rightarrow X_s \ell^+ \ell^-$…
Predictions are made for the forward-backward and charge asymmetries in bottom-quark pair production at hadron colliders. Tree-level exchanges of electroweak (EW) gauge bosons dominate the Standard Model (SM) contribution to the asymmetry…
The measured value of A_b, the Z \bar bb asymmetry parameter, disagrees with the Standard Model at 99% confidence level. If genuine the discrepancy could indicate new interactions unique to third generation quarks, implying enhanced Z…
We investigate how far a new physics scenario affecting primarily the third generation fermions can ameliorate the tension between B-decay observables and Standard Model expectations. Adopting a model-independent approach, we find that…
The transition from formulations with extra dimensions to Kaluza-Klein theories, aimed at extending the Standard Model, bears the ingredients of hidden symmetries and the Kaluza-Klein mechanism for mass generation. We explore these…
The Kaluza-Klein theory and Randall-Sundrum theory are examined comparatively, with focus on the behavior of the five dimensional (Dirac) fermion in the dimensional reduction to four dimensions. They are properly treated using the Cartan…
In the model of Arkani-Hamed and Schmaltz the various chiral fermions of the Standard Model(SM) are localized at different points on a thick wall which forms an extra dimension. Such a scenario provides a way of understanding the absence of…
We consider massive deformation of $U(2)$ gauge bosons in a recently developed holonomy formalism and propose a novel electroweak model. The massive gauge bosons arise from massive deformation of spinor momenta, which implies that the mass…
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…
The present data on a number of observables in $b\to s\mu^+\mu^-$ processes manifest some tensions with the standard model (SM). Assuming that these anomalies have a new physics origin, we consider the possibility that a $Z'$ boson is…
The deviation of the experimental value of $R_b \equiv \Gamma_b/\Gamma_h$ from the standard-model prediction can be naturally explained in the extended technicolor scenario.The diagonal extended technicolor gauge boson which…
We investigate whether models with flat extra dimensions in which SM fields propagate can give a significant contribution to the anomalous magnetic moment of the muon (MMM). In models with only SM gauge and Higgs fields in the bulk, the…
In models with low-energy supersymmetry breaking, an anomalous Abelian horizontal gauge symmetry can simultaneously explain the fermion mass hierarchy and the values of the $\mu$ and $B$ terms. We construct an explicit model where the…