Related papers: Decays of Positronium
The existing discrepancy between neutron lifetime measurements in bottle and beam experiments has been interpreted as a sign of the neutron decaying to dark particles. We summarize the current status of this proposal, including a discussion…
The status of the solar neutrino problem is reviewed. Attempts to explain the observed deficit and spectral distortion, both by astrophysical and particle physics methods, are described. It is argued that the comparison of all experiments…
We present details of our recent calculation of alpha^2 corrections to the parapositronium decay into two photons. These corrections are rather small and our final result for the parapositronium lifetime agrees well with the most recent…
After the recent experimental results on neutrino oscillations, some shape starts to emerge from the puzzle. However, the situation is still far from being clarified. First of all, accommodating all experimental results in a single and…
We investigate the invisible decay of positronium to probe the fermionic light dark matter mediated by the dark $Z$ boson. Too tiny is the invisible decay rate of positronium through weak interaction in the standard model to be detected in…
We present a calculation of the branching ratio of orthopositronium decay into an invisible mode, which is done in the context of Mirror World models, where ordinary positronium can disappear from our world due to oscillation into its…
High-order perturbative corrections to positronium decays and hyperfine splitting are briefly reviewed. Theoretical predictions are compared to the most recent experimental data. Perspectives of future calculations are discussed.
We determine the rates and energy and angular distributions of the positronium decays into a photon and a neutrino-antineutrino pair, Ps-->gamma+nu+anti-nu. We find that both positronium spin states have access to this decay channel,…
We examine the constraints on non-radiative decay of neutrinos from the observations of solar neutrino experiments. The standard oscillation hypothesis among three neutrinos solves the solar and atmospheric neutrino problems. Decay of a…
Despite its very short lifetime positronium provides us with a number of accurate tests of the bound state QED. In this note a brief overview of QED theory and precision experiments on the spectrum and annihilation decay of the positronium…
I consider the problem of the evaluation of the orthopositronium decay rate, including second order radiative corrections. I present a brief theoretical discussion of this problem and a review of the results available in literature, and,…
The two-particle wave function of neutrino and antineutrino after the decay of a Z boson is found as a solution of an initial value problem. The wave packet of this state involves the coherent superposition of massive neutrinos and…
We present a short review of the existing evidence in favor of neutrino mass and neutrino oscillations which come from different kinds of experiments. We focus our attention in particular on solar neutrinos, presenting a global updated…
Neutrino decay in vacuum has often been considered as an alternative to neutrino oscillations. Because non-zero neutrino masses imply the possibility of both neutrino decay and neutrino oscillations, we present a model-independent formal…
Oscillation experiments show that neutrinos have masses. They however only determine the neutrinop mass differences. Information on the absolute masses can be obtained by studying the kinematics in weak decays, or by searching for…
On the basis of phenomenological model of the orthopositronium annihilation "isotope anomaly" in gaseous neon (lifetime spectra, positrons source Na-22) the realistic estimation of an additinal mode ~0.2%) of the orthopositronium…
The Majorana paper ``Symmetrical theory of the electron and positron'' is briefly reviewed. The present status of Majorana neutrinos is discussed.
The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A…
It is shown how deviations of neutrino flavor mix from the canonical 1 : 1 : 1 in high energy astrophysical neutrinos can provide evidence for neutrino decays with lifetimes as long as $10^4 s/eV$.
Positronium (the bound state of electron and positron) has been thought to be formed after proton decay ($>10^{34}$yr) through collisional recombination and then decays by pair annihilation, thereby changing the matter content of the…