Related papers: Parapositronium can decay into three photons
The construction of positronium decay amplitudes is handled through the use of dispersion relations. In this way, emphasis is put on basic QED principles: gauge invariance and soft-photon limits (analyticity). A firm grounding is given to…
Nuclear parity violation is studied with polarized neutrons in the photodisintegration of the deuteron at low energies. A pionless effective field theory with di-baryon fields is used for the investigation. Hadronic weak interactions are…
We present a precise theoretical prediction for the decay width of the bound state of two electrons and a positron (a negative positronium ion), Gamma(Ps^-) = 2.087 085(12)/ns. We include O(alpha^2) effects of hard virtual photons as well…
Motivated by recent observations from Pamela, Fermi and H.E.S.S., we consider dark matter decays in the framework of supersymmetric SU(5) grand unification theories. An SU(5) singlet S is assumed to be the main component of dark matters,…
Photon branching ratios are critical input data for activities such as nuclear materials protection and accounting because they allow material compositions to be extracted from measurements of gamma-ray intensities. Uncertainties in these…
The present status of theoretical and experimental investigations of the decay rate of a positronium is considered. The increasing interest to this problem has been caused by the disagreement of the calculated value of $\Gamma_3 (o-Ps)$ and…
Single photons produced by fundamentally dissimilar physical processes will in general not be indistinguishable. We show how photons produced from a quantum dot and by parametric down-conversion in a nonlinear crystal can be manipulated to…
The phase between three-gluon and one-photon amplitudes in psi(2S) and psi(3770) decays is analyzed.
A photon exhibits a tiny anomalous magnetic moment $\mu_{\gamma}$ due to its interaction with an external constant magnetic field in vacuum through the virtual electron-positron background. It is paramagnetic ($\mu_{\gamma}>0$) in the whole…
The lighter top squark in supersymmetry can live long enough to form hadronic bound states if it has no kinematically allowed two-body decays that conserve flavor. In this case, scalar stoponium may be observable through its diphoton decay…
If the stop is the next-to-lightest supersymmetric particle (NLSP) and the mass difference to the neutralino is smaller than the top mass, it can decay via flavour-violating decay modes to $c\tilde{\chi}^0_1/u\tilde{\chi}^0_1$ or a…
We report measurements of differential cross sections and decay asymmetries of incoherent $\phi$-meson photoproduction from the deuteron at forward angles using linearly polarized photons at \Eg=1.5-2.4 GeV. The nuclear transparency ratio…
The mixing of photons with light pseudoscalars in the presence of external electromagnetic fields has been used extensively to search for axion-like-particles. A similar effect for dark photon propagating states is usually not considered…
We simulate numerically the photodissociation of molecules into noncondensate atom pairs that accompanies photoassociation of an atomic Bose-Einstein condensate into a molecular condensate. Such rogue photodissociation sets a limit on the…
We study the decay of the standard model Z boson into unparticle plus a single photon through a one-loop process. As in the anomaly type decay, only the axial-vector part of the Z coupling matching with the vector unparticle and/or the…
The non-relativistic energy levels of para-positronium are calculated in the quadrupole approximation of the interaction potential. This approximation technique takes into account the anisotropy of the electrostatic electron-positron…
The quantum electrodynamical theory of the three-photon transitions in hydrogen-like ions is presented. Emission probabilities of various three-photon decay channels for $ 2p_{3/2} $, $ 2p_{1/2} $ and $ 2s_{1/2} $ states are calculated for…
The photodisintegration of $^{3}$H is treated by means of coupled integral equations using separable versions of the Paris and the Bonn potentials in their kernel. The differential cross section for the inverse reaction is obtained via…
In realistic supersymmetric models, very small hard supersymmetry breaking terms generally appear. Some of them violate baryon and/or lepton number. We discuss their possible applications to proton decay and generation of neutrino masses.
A decay rate asymmetry of the top quark is discussed within the framework of the supersymmetric standard model. Although new sources of CP violation in this model are severely constrained from the electric dipole moments of the neutron and…