Related papers: Three-Loop Reducible Radiative Photon Contribution…
We have calculated the contribution to the positronium hyperfine splitting at order $m \alpha^7$ of the light-by-light scattering process in the exchange of two photons between the electron and positron. Our result is $\Delta E =…
The uncertainty in the contribution to the Lamb shift in muonic hydrogen, $\Delta E^{subt}$ arising from proton polarizability effects in the two-photon exchange diagram at large virtual photon momenta is shown large enough to account for…
Next-to-leading order corrections to fragmentation functions in a light-cone gauge are discussed. This gauge simplifies the calculation by eliminating many Feynman diagrams at the expense of introducing spurious poles in loop integrals. As…
We present the analytic expressions for the color-planar contributions to the heavy-light form factors at three loops in perturbative QCD. These form factors play an important role in the precision predictions of various observables in top…
The next-to-next-to-leading order (NNLO) corrections in massless perturbative QCD are derived for the parton distributions of the photon and the deep inelastic structure functions F_1^gamma and F_2^gamma. We present the full photonic…
The radiative corrections to the pure leptonic decay $B_c \to \ell\nu_{\ell}$ up-to one-loop order is presented. How to cancel the infrared divergences appearing in the loop calculations, and the radiative decay $B_c \to…
The Lamb shift in muonic hydrogen was measured some time ago to a high accuracy. The theoretical prediction of this value is very sensitive to the proton-finite-size effects. The proton radius extracted from muonic hydrogen is in…
We provide a compendium of techniques that can be used to compute $O(N_f\alpha^2)$ corrections to low-energy electroweak processes. Specifically, these are the 2-loop electroweak corrections containing a light fermion loop. It is shown that…
Analytical expressions for the tenth order electromagnetic corrections to the lepton ($L=e, ~\mu $ and $\tau$) anomaly $a_L$ are derived explicitly for a class of Feynman diagrams with insertions of the vacuum polarization operator…
The contribution of pseudoscalar pole diagrams to the hadronic light-by-light corrections of order alpha^3 E_F to the ground state hyperfine splitting in hydrogenic atom is calculated in the pseudoscalar pole terms approximation. The vector…
We calculate convergent 3-loop Feynman diagrams containing a single massive loop equipped with twist $\tau =2$ local operator insertions corresponding to spin $N$. They contribute to the massive operator matrix elements in QCD describing…
An expression for the Dalitz plot of the semileptonic decay of a charged kaon, including radiative corrections to order O[\alpha \pi)(q/M_1)], where q is the four-momentum transfer and M_1 is the mass of the decaying kaon, is obtained.…
We have recalculated the Mikaelian and Smith radiative corrections to the Dalitz decay $\pi^0\to e^+e^-\gamma$ beyond the soft-photon approximation, i.e. over the whole range of the Dalitz plot and with no restrictions on the radiative…
We calculate the one-photon loop radiative corrections to the neutral pion-pair photoproduction process $\pi^-\gamma \to \pi^-\pi^0\pi^0$. At leading order this reaction is governed by the chiral pion-pion interaction. Since the chiral…
The leading heavy-top two-loop corrections to the \Zbb~vertex are determined from a direct evaluation of the corresponding Feynman diagrams in the large \Mt~limit. %The calculation is done in the naive %dimensional regularization scheme…
Radical-ion pairs, fundamental for understanding photosynthesis and the avian magnetic compass, were recently shown to be biological open quantum systems. We here show that the coupling of the radical-pair's spin degrees of freedom to its…
Three-loop quantum corrections to the effective action are calculated for N=1 supersymmetric electrodynamics, regularized by higher derivatives. Using the obtained results we investigate the anomaly puzzle in the considered model.
We quantify a limitation in the usual accounting of the finite-size effects, where the leading $[(Z\alpha)^4]$ and subleading $[(Z\alpha)^5]$ contributions to the Lamb shift are given by the mean-square radius and the third Zemach moment of…
Atmospheric refraction modifies the apparent position of objects in the sky. We computed the lateral translation that is to be considered for short-range applications, such as wavefront sensing and meteor trajectories. We aim to calculate…
We present for the first time the complete three-loop mixed electroweak-QCD ($\mathcal{O}(\alpha\alpha_s)$) corrections for the decay channel $H \to \gamma\gamma$, by implementing three different on-shell $\alpha$ schemes in computing the…