Related papers: Z to b bbar and Chiral Currents in Higgsless Model…

The B -> X_s l+ l- decay rate is known at the next-to-next-to-leading order in QCD. It is proportional to alpha_em (mu)^2 and has a +- 4% scale uncertainty before including the O(alpha_em log(M_W^2/m_b^2)) electromagnetic corrections. We…

We analyze the corrections to the precision EW observables in minimal composite Higgs models by using a general effective parametrization which also includes the lightest fermionic resonances. A new, possibly large, logarithmically…

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 discuss exclusive charmless B decays within the Standard Model of particle physics. In particular, we consider hadronic two-body decays as B -> pi pi and perform a conceptual analysis of heavy-to-light form factors which encode the…

We construct a conformal lattice theory with only gauge degrees of freedom based on the induced non-local gauge action in QED$_3$ coupled to large number of flavors $N$ of massless two-component Dirac fermions. This lattice system displays…

I study bottom quark fragmentation in the Standard Model Higgs decay H->b bbar, within the framework of perturbative fragmentation functions. I resum large collinear logarithms ln(m_H^2/m_b^2) in the next-to-leading logarithmic (NLL)…

We calculate the leading logarithmic QCD corrections to the decay B_s --> \gamma \gamma in the two Higgs doublet model (2HDM) including O_7 type long distance effects and estimate the restrictions of the 2HDM parameters, tan\beta and m_H,…

We examine the experimental observability of the decay mode $t \rightarrow c g$ at the Fermilab Tevatron via the flavor-changing neutral current vertex $t \bar c g$. We find that with the existing data, one should be able to probe the $t…

I discuss the possible effects of a finite density of localised near-zero Dirac modes in the chiral limit of gauge theories with $N_f$ degenerate fermions. I focus in particular on the fate of the massless quasi-particle excitations…

We study three-body charmless baryonic B decays of $B \to \Lambda\bar\Lambda P$ with $P=\pi$ and $K$ in the standard model. We find that the branching ratios of the $K$ modes are about one order of magnitude larger than those of the…

In the heavy quark limit, both vector mesons in the charmless B -> VV decay should have zero helicity and the corresponding amplitude is proportional to the form factor difference $(A_1-A_2)$. The first observed charmless $B\to VV$ mode,…

We consider various constraints on Higgsless models of electroweak symmetry breaking based on a bulk SU(2)_L x SU(2)_R x U(1)_{B-L} gauge group in warped space. First we show that the S parameter which is positive if fermions are localized…

We comprehensively study the charged-Higgs contributions to the leptonic $B^-_q \to \ell \bar \nu$ ($q=u,c$) and semileptonic $\bar B \to X_q \ell \bar\nu$ ($X_u=\pi, \rho; X_c=D,D^*$) decays in the type-III two-Higgs-doublet model (2HDM).…

We study the decay width, forward-backward asymmetry and the longitudinal lepton polarization for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse…

We present the first calculation of the two-loop electroweak fermionic correction to the flavour-dependent effective weak-mixing angle for bottom quarks, sin^2 theta_{eff}^{b anti-b}. For the evaluation of the missing two-loop vertex…

The decay mode D^0 -> K^0 \bar{K^0} has no factorizable contribution. We calculate the nonfactorizable chiral loop contributions of order O(p^3)and then we use a heavy-light type chiral quark model to calculate nonfactorizable tree level…

B-decays mediated by both charged currents and neutral currents have provided hints of violation of lepton flavour universality. By assuming an explanation of these anomalies in terms of new physics at the TeV scale affecting the third…

We study the phenomenology of the 4-site Higgsless model, based on the $SU(2)_L\times SU(2)_1\times SU(2)_2\times U(1)_Y$ gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge…

Recently, the ATLAS and CMS collaborations jointly announced the first evidence of the rare Higgs boson decay channel $H\to Z\gamma$, with a ratio of $2.2\pm 0.7$ times the leading order standard model (SM) prediction. In order to face this…

We report new results for a frequently discussed gauge theory with twelve fermion flavors in the fundamental representation of the SU(3) color gauge group. The model, controversial with respect to its conformality, is important in…