Related papers: Probing the Scalar Sector in $e^+ e^- \to Z \phi$
The rare B_s-> \phi \ell^+ \ell^- decay is investigated by using the most general model independent effective Hamiltonian for $\ell= \mu, \tau$. The calculated $Br(B_s \rar \phi \mu^+ \mu^-) = 1.92 \times 10^{-6}$ is in consistent with the…
From $1310.6\times10^{6}$ $J/\psi$ and $448.1\times10^{6}$ $\psi(3686)$ events collected with the BESIII experiment, we report the first observation of $\Sigma^{+}$ and $\bar{\Sigma}^{-}$ spin polarization in $e^+e^-\rightarrow J/\psi…
We study the possibility of fingerprinting a strongly interacting $W$ boson sector which is consistent with present day LHC searches at the ILC with longitudinal as well as transversely polarized electron and positron beams. We account for…
Effects are investigated of CP symmetry violation in the decay of a scalar particle X (the Higgs boson) into two off-mass-shell Z bosons both decaying into a fermion-antifermion pair, $X \to Z_1^* \, Z_2^* \to f_1 \bar{f_1} \, f_2…
We discuss top quark production and its subsequent decay for searching new physics at lepton colliders. The angular dependence of the decay leptons is calculated including both QCD corrections and anomalous gamma Z - t tbar couplings. The…
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…
A model independent formalism for the electron positron annihilation reaction $e^++e^-\to a_1(1260)+\pi $ has been derived. The differential and total cross sections and the elements of the spin--density matrix of the $a_1$-meson were…
We show that the CP-violating dipole form factors of the tau lepton can be of the order of $\alpha/\pi$ in units of the length scale set by the inverse $Z$ boson mass. We propose a few observables which are sensitive to these form factors…
This work offers the constraints on the anomalous neutral triple gauge couplings for the process $e^+e^- \to ZZ $ at the CLIC with $\sqrt{s}=3$ TeV. The realistic CLIC detector environments and their effects are considered in our analysis.…
We propose to test the CP symmetry in the reactions Z -> mu+ mu- gamma and Z -> tau+ tau- gamma. The experimental analysis of angular correlations allows to determine a set of effective couplings: the electric and weak dipole moments of the…
We consider the spin orentation of the final Z bosons for the processes in the Standard Model. We demonstrate that at the threshold energies of these processes the analytical expressions for the Z boson polarization vectors and alignment…
In this paper we explore CP discrimination in the associated production of top-quark pairs ($t\bar{t}$) with a generic scalar boson ($\phi$) at the LHC. We probe the CP-sensitivity of several observables for a varying scalar boson mass and…
We present a complete description of angular distributions in the presence of new interactions for the process e+ e- -> Z gamma with polarized beams at future linear colliders, by considering the most general form-factors allowed by gauge…
We study the radiative $\phi\to K^0\bar{K}^0\gamma$ decay within a phenomenological framework by considering the contributions of the $f_{0}(980)$ and $a_{0}(980)$ scalar resonances. We calculate the branching ratio $B(\phi\to…
New heavy neutral gauge bosons Z' are predicted by many models of physics beyond the Standard Model. It is quite possible that Z's are heavy enough to lie beyond the discovery reach of the CERN Large Hadron Collider LHC, in which case only…
The Z line shape is measured at LEP with an accuracy at the per mille level. Usually it is described in the Standard Model of electroweak interactions with account of quantum corrections. Alternatively, one may attempt different…
We report on a search for the charmless decays $B^{+} \to\phi\pi^{+}$ and $B^{0} \to\phi \pi^{0}$ that are strongly suppressed in the Standard Model. The analysis is based on a data sample of $657 \times 10^6$ $B \bar{B}$ pairs collected at…
Electromagnetic form factors serve to explore the intrinsic structure of nucleons and their strangeness partners. For the decay $\Sigma^0\to\Lambda e^+e^-$, due to limited phase space, the effects caused by the Sigma-to-Lambda transition…
The heavy Z' boson with family nonuniversal couplings can introduce flavour changing effects. Constraints on nondiagonal Z' couplings coming from the \mu-e conversion in a muonic atom, K^0 - \bar{K^0} and B - \bar{B} mixing, epsilon and…
The transverse spin effects may be helpful to distinguish between scalar (J^{PC}=0^{++}) or pseudoscalar (J^{PC}=0^{-+}) nature of the spin zero (Higgs) particle once discovered in future accelerator experiments. The correlations can…