Related papers: Axial Contributions at the Top Threshold
We discuss the resummation of the potentially large O((\beta_0\alpha_s)^n) QCD corrections to the total cross section of the process e^+e^- \to t \bar t near the threshold. In this approximation, the cross section factorization into the…
We re-investigate Adler's PCAC relation in the presence of an external electromagnetic field within the framework of QCD coupled to external fields. We discuss pion electroproduction within a tree-level approximation to chiral perturbation…
The cross sections of the Higgs production and the corresponding backgrounds of $e^+e^-$ annihilations at the CEPC (Circular Electron and Positron Collider) are calculated by a Monte-Carlo method, and the beamstruhlung effect at the CEPC is…
We analyze the pair-production of top quarks in polarized $e^+e^-$ scattering in the presence of electroweak dipole moments. For this, we consider two $CP$-odd observables which probe both the real and the imaginary parts of these moments.…
The production of the vector meson pairs $B_s^* \bar B_s^*$ in the $e^+e^-$ annihilation is generally contributed by two $P$ wave amplitudes with different total spin $S$ of the mesons, $S=0$ and $S=2$, and also by an $F$ wave amplitude.…
It was reported that the NNLO correction to the total cross section near the ttbar threshold in e+e- collisions is as large as the NLO correction to it. In the thesis, we improve the convergence of the perturbative series of the total cross…
In this dissertation, a complete calculation of QED radiative corrections is presented for total cross sections and forward- backward asymmetries for s-channel fermion pair production in e+e- annihilation with kinematical cuts to the final…
Our original suggestion to investigate exclusive $\pi^0$ electroproduction as a method for extracting the tensor charge, transversity, and other quantities related to chiral odd generalized parton distributions from cross section and…
Recently the BaBar Collaboration published new data on the cross section for the annihilation e+e- -> phi pi0, obtained using the initial state radiation technique at a center of mass energy of 10.6 GeV. Such a process represents an…
In this article we compute the cross section for the process $e^+e^- \to Q\overline Q+X$, with $Q$ a heavy quark, differential in a given event shape $e$ and the angle $\theta_T$ between the thrust axis and the beam direction. These…
We consider the differential cross section of electron-positron pair production by a high-energy photon in a strong Coulomb field close to the end of the electron or positron spectrum. When the momentum transfer largely exceeds the electron…
Two-photon annihilate contributions in the process $e^+ + e^- \to p + \bar{p}$ including $N$ and $\Delta$ intermediate are discussed in a simple hadronic model. The corrections to the unpolarized cross section and polarized observables…
We propose an interpolating formula for the amplitude induced by the axial anomaly, concentrating on the $\pi^0\gamma^{\ast}\gamma^{\ast}$ transition form factor. The QCD corrections to this amplitude are generally described by two major…
To gain some sense about the likelihood of measuring the Higgs boson quartic coupling, we calculate the contribution to the triple Higgs production cross section from the subprocesses $q\bar{q}\to ZHHH$ and $q\bar{q}'\to WHHH$. Our results…
Extensions of the Standard Model with extra neutral currents due to additional anomalous abelian gauge factors are considered. We summarize the main features of the effective action associated to these theories. They are characterized by an…
We set up a formalism, within the antenna subtraction framework, for computing the production of a massive quark-antiquark pair in electron positron collisions at next-to-next-to-leading order in the coupling $\alpha_s$ of quantum…
We discuss the production of two hadrons in e+e- annihilation within the framework of perturbative QCD. The cross section for this process is calculated to next-to-leading order accuracy with a selection of variables that allows the…
The differential cross sections \sigma_0=\sigma_T+\epsilon \sigma_L, \sigma_{LT}, and \sigma_{TT} of \pi^0 electroproduction from the proton were measured from threshold up to an additional center of mass energy of 40 MeV, at a value of the…
The effects of the finite top quark width in the top pair production cross section close to the threshold are discussed in this talk. We introduce a $t\bar{t}$ cross section with a cut on the invariant masses of the top and antitop that can…
In this work we present for the first time predictions for top-quark pair differential distributions at the LHC at NNLO QCD accuracy and including EW corrections. For the latter we include not only contributions of ${\cal O}(\alpha_s^2…