Related papers: Large forward-backward asymmetry in B --> K mu+ mu…
The modern viewpoint is that the Standard Model is the leading part of an effective field theory that obeys the symmetry $SU(3)_C \times SU(2)_L \times U(1)_Y$. Since the discovery of the Higgs boson, it is generally assumed that this…
Using the analytic properties of two-point functions in QCD, as well as unitarity, bounds on the B meson form factor F(q^2) can be derived. Heavy quark spin symmetry, correctly taken into account, is shown to improve these bounds…
We present a model-independent analysis of rare B decays, $B \to K^{(*)} \nu \nu$. The effect of possible new physics is written in terms of dimension-6 four-fermi interactions. The lepton number violating scalar- and tensor-type…
It is well known that New Physics can contribute to weak decays of heavy mesons via virtual processes during its decays. The discovery of New Physics, using such decays is made difficult due to intractable strong interaction effects needed…
Heavy neutral gauge boson $Z^\prime$ is proposed in many new physics models. It has rich phenomena at the future muon collider. We study the properties of $Z^\prime$ boson with the process of $\mu^+ \mu^- \rightarrow q \bar{q}$, $\mu^+…
We list all possible dim=6 CP conserving and SU(3)* SU(2)*U(1) gauge invariant interactions, which could be generated in case no new particles would be reachable in the future Colliders, and the only observable New Physics would be in the…
In a recent paper we performed a comprehensive study of the impact of new-physics operators with different Lorentz structures on $\BDstarellnu$ decays, $\ell = e^-, \mu^-, \tau^- $, involving the $b \to c l \nu_\ell$ transition. In this…
The symmetries arise due to heavy quark and large energy limit help us to reduce the number of independent form factors in the heavy-to-light $B$-meson decays. It is expected that these symmetry relations are not exact and are broken by the…
We derive constraints on Wilson coefficients of dimension-six effective operators probing the b --> s transition, using recent improved measurements of the rare decays Bs --> mu+mu-, B --> K mu+mu- and B --> K* mu+mu- and including all…
We report a measurement of the forward-backward asymmetry, $A_{FB}$, in $b\bar{b}$ pairs produced in proton-antiproton collisions and identified by muons from semileptonic $b$-hadron decays. The event sample was collected at a…
We study some New Physics effects on the hadronic decays of the Top quark, like t-> b bbar c, and on a forward-backward-like CP even asymmetry A_t constructed in such a way that it is zero in the SM. We find that an anomalous right-handed…
Motivated by recent measurements of the top quark forward-backward asymmetry at the Tevatron, we study how t-channel new physics can contribute to a large value. We concentrate on a theory with an abelian gauge boson possessing flavor…
The forward-backward asymmetry ${\cal A}_{\rm FB}$ in $B\to K^*\ell^+\ell^-$ decay is a sensitive probe of New Physics. Previous studies have focused on the sensitivity in the position of the zero. However, the short distance effective…
The bottom quark forward-backward asymmetry $A_{\rm{FB}}$ is a key observable in electron-positron collisions at the $Z^{0}$ peak. In this paper, we employ the Principle of Maximum Conformality (PMC) to fix the $\alpha_s$-running behavior…
We adopt a Markov Chain Monte Carlo method to examine various new physics models which can generate the forward-backward asymmetry in top quark pair production observed at the Tevatron by the CDF Collaboration. We study the following new…
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 revisit the relation between the asymmetries $A_{FB}$ and $A_{FB}^\ell$ in $t \bar t$ production at the Tevatron, using as new physics benchmark a colour octet. We find that $A_{FB}^\ell$ receives large contributions from the…
We investigate the light-front zero-mode contribution to the weak transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. In particular, we discuss the form factors…
Recently several measurements in the neutral current sector $b\rightarrow s l^+l^-$ ($l=e$ or $\mu$) as well as in the charged current sector $b \rightarrow c \tau \bar{\nu}$ show significant deviations from their Standard Model…
The confirmation of excess in $R_{D^*}$ at the LHCb is an indication of lepton flavor non-universality. Various different new physics operators and their coupling strengths, which provide a good fit to $R_D$, $R_{D^*}$ and $q^2$ spectra,…