Related papers: Sum rules for asymptotic form factors in $e^+ e^- …
This article is devoted to calculating the form factors of $B_c \to D^{*}$, $B_c \to D$, $B_c \to D_s^{*}$ and $B_c \to D_s$ transitions in the framework of three-point QCD sum rules. At the QCD side, the contributions of…
We define form factors and scattering amplitudes in Conformal Field Theory as the coefficient of the singularity of the Fourier transform of time-ordered correlation functions, as $p^2 \to 0$. In particular, we study a form factor…
We study long-distance effects in rare exclusive semileptonic decays B -> K_{1}ell ^{+}ell ^{-}, K_{1} is the axial vector meson.The form factors, describing the meson transition amplitudes of the effective Hamiltonian, are calculated using…
We study the anomalous $W^+W^-V$ ($V=\gamma,Z$) couplings in $e^+e^-\to W^+W^-$ using the complete set of polarization observables of $W$ boson with longitudinally polarized electron ($e^-$) and positron ($e^+$) beams. For the effective…
The electromagnetic form factors calculated through Euclidean Bethe-Salpeter amplitude and through the light-front wave function are compared with the one found using the Bethe-Salpeter amplitude in Minkowski space. The form factor…
For a relativistic system of two scalar particles, we find the Bethe-Salpeter amplitude in Minkowski space and use it to compute the electromagnetic form factor. The comparison with Euclidean space calculation shows that the Wick rotation…
The scattering of $W$, $Z$ and Higgs bosons in the Standard Model is investigated in the region $s,m_H^2\gg m_W^2$ with no restrictions on relative sizes of $s$ and $m_H^2$, so that our results are applicable at energies below as well as…
We study the sensitivity of the process $\mu^-\mu^+\to HH$ to the $q^2$-dependence of the $HHH$ form factor, which can reflect the Higgs boson structure, especially in the case of compositeness. We compute the Born and 1 loop SM…
Form factors parameterizing the semileptonic decay $B_{c}\rightarrow D_{s}^{\ast}l^{+}l^{-}$ ($l=\mu ,\tau $) are calculated using the frame work of Ward Identities. These form factors are then used to calculate the physical observables…
Form factors for $\alpha+{^{12}}$C inelastic scattering are obtained within two theoretical ($\alpha+\alpha+\alpha$) approaches: The hyperspherical framework for three identical bosons, and the algebraic cluster model assuming the $D_{3h}$…
The gravitational form factors are related to the matrix elements of the energy-momentum tensor $T^{\mu\nu}$. Using the light front wave functions of the scalar quark-diquark model for nucleon predicted by the soft-wall AdS/QCD, we…
Dispersive constraints on the shape of the form factors which describe the exclusive decays B -> D^(*) l nu are derived by fully exploiting spin symmetry in the ground-state doublet of heavy-light mesons. The analysis includes all twenty…
Using the form factors calculated in the three-point QCD sum rules approach, we calculate the new physics contributions to the physical observables of $B_c \to D_s^* \mu^+\mu^-$ decay in the family non-universal $Z^{\prime}$ model. Under…
The $W$-boson pair production in $e^-e^-$ collisions with polarized beams is investigated. The helicity amplitudes are derived for general couplings and the conditions for a good high-energy behaviour of the cross-section are given. The…
In the $\rm SU(3)_F$ symmetry limit, using two- and three-particle distribution amplitudes of $B^{\pm}$-meson for $B_s$, the transition form factors of semileptonic $B_{s}\to K_{0}^*(1430)$ decays are calculated in the framework of the…
We review the role of the Higgs boson in preserving unitarity of the scattering amplitudes in the Standard Model (SM). We will look at the processes $\nu_e + \bar{\nu}_e \rightarrow W^-_L +W^+_L $, $ W^-_L + W^+_L \rightarrow W^-_L +W^+_L $…
Taking into account the gluon condensate contributions, the form factors of the semileptonic $B_c^- \to D^{*0}\ell\nu$ transition with $l=\tau, e$ are calculated in the framework of the three point QCD sum rules. The heavy quark effective…
We extend previous work on sum rules for the invariant amplitudes of pion Compton scattering by deriving a complete lowest order perturbative spectral function - and its leading non perturbative power corr ections - for a specific…
We derive new QCD sum rules for $B\to D$ and $B\to D^*$ form factors. The underlying correlation functions are expanded near the light-cone in terms of $B$-meson distribution amplitudes defined in HQET, whereas the $c$-quark mass is kept…
Extending earlier investigations, we analyze the quasi-elastic scattering of strongly interacting electroweak bosons at high-energy e+-e- colliders. The three processes e+e- -> bar-nu nu W+W-, bar-nu nu ZZ, and e-e- -> W-W- are examined at…