Related papers: The Two Loop Long Range Effect on the Proton Decay…
Positronium decay rates are computed at the one-loop level, using convolution-type factorized amplitudes. The dynamics of this factorization is probed with dispersion relations, showing that unallowed approximations are usually made, and…
In many calculations of the two--photon decay of hadronic molecules, the decay matrix element is estimated using the wave function at the origin prescription, in analogy to the two-photon decay of parapositronium. We question the…
We present a theoretical framework within which both the real and imaginary parts of the complex, two-photon exchange amplitude contributing to $K_L\rightarrow\mu^+\mu^-$ decay can be calculated using lattice QCD. The real part of this…
The decay of the Standard Model Higgs boson in the intermediate-mass range into gluons is considered where special emphasis is put on the influence of the leading electroweak corrections proportional to G_F m_t^2. An effective Lagrangian…
We make a comprehensive investigation of the Lorentz invariance violation (LIV) effects that may occur in two-neutrino double-beta ($2\nu\beta\beta$) decay for all the experimentally interesting nuclei. We deduce the formulas for the LIV…
The perturbatively calculable short distance QCD potential is known to two loops including the effect of massive quarks. Recently, a simple approximate solution in momentum space was utilized to obtain the potential in coordinate space. The…
We compute the two-loop corrections to the coefficient of the b --> s gamma magnetic penguin present in the limits of heavy top and/or heavy higgs. This kind of corrections affects in a significant way the observables measured at LEP. On…
Recent results on measurements of the strong coupling $\alpha_S$ from LEP are reported. These include analyses of the 4-jet rate using the Durham or Cambridge algorithm, of hadronic $Z^0$ decays with hard final state photon radiation, of…
From a fit to the experimental data on the $b\bar{b}$ fine structure, the two-loop coupling constant is extracted. For the 1P state the fitted value is $\alpha_s(\mu_1) = 0.33 \pm 0.01(exp)\pm 0.02 (th)$ at the scale $\mu_1 = 1.8 \pm 0.1$…
It was argued recently that loop corrections to tree-level amplitudes are essential in the discussion of the collisional energy loss of energetic partons in the hot quark gluon plasma: Instead of $dE_{\rm coll}^B/dx \sim \alpha^2 T^2…
We study the strong corrections to the Higgs coupling to two photons. This coupling is the dominant mechanism for Higgs production in photon-photon collisions. In addition, the two photon decay mode of the Higgs is an important and…
The loop expansion is applied to a chiral effective hadronic lagrangian; with the techniques of Infrared Regularization, it is possible to separate out the short-range contributions and to write them as local products of fields that are…
The coupling constant of the strong force is determined from the transverse-momentum distribution of $Z$ bosons produced in 8 TeV proton-proton collisions at the LHC and recorded by the ATLAS experiment. The $Z$-boson cross sections are…
Calculations of the two-loop electron self-energy for the $n = 1$ and $n = 2$ states of hydrogen-like ions are reported, performed to all orders in the nuclear binding strength parameter $Z\alpha$ (where $Z$ is the nuclear charge number and…
We use classical electron ensembles and the aligned-electron approximation to examine the effect of laser pulse duration on the dynamics of strong-field double ionization. We cover the range of intensities $10^{14}-10^{16} W/cm^2$ for the…
We describe a calculation of the two-photon decays of heavy vector-mesons, $B^*\to B\gamma\gamma$ and $D^*\to D\gamma\gamma$, by using the ``heavy meson chiral Lagrangian''. The decay amplitudes are expressed in terms of the strong coupling…
By means of a heavy-top-quark effective Lagrangian, we calculate the three-loop corrections of O(alpha_s^2 G_F M_t^2) to the H->bb-bar partial decay width of the standard-model Higgs boson with intermediate mass M_H<<2M_t. We take advantage…
We consider an effective field theory for the nonleptonic decay in which a heavy quark decays into a pair of a heavy quark and antiquark having a small relative velocity and one relativistic (massless) quark. This effective theory is a…
We consider the two Higgs doublet model extension of the Standard Model in the limit where all physical scalar particles are very heavy; too heavy, in fact, to be experimentally produced in forthcoming experiments. The symmetry breaking…
We present a systematic method for determining the two-loop effective Lagrangian resulting from integrating out a set of heavy particles in an ultraviolet scalar theory. We prove that the matching coefficients are entirely determined from…