Related papers: Improved Upper Limits on Baryon-Number Violating D…
We study the pion decays with intermediate on-shell neutrinos $N$ into two electrons and a muon, $\pi^{\pm} \to e^{\pm} N \to e^{\pm} e^{\pm} \mu^{\mp} \nu$. We investigate the branching ratios ${\rm Br}_{\pm} = [\Gamma(\pi^- \to e^- e^-…
In the near future, the Deep Underground Neutrino Experiment and the European Spallation Source aim to reach unprecedented sensitivity in the search for neutron-antineutron ($n\text{-}\bar{n}$) oscillations, whose observation would directly…
We extend our recent analysis of the dilepton and photon emission rates to the case of finite temperature and baryon density, within the context of a density expansion. To leading order, the effects of the baryon density are assessed using…
We consider four lepton-number violating (\lv) processes: (a) neutrinoless double-beta decay (0\nu\beta\beta), (b) Delta L = 2 tau decays, (c) Delta L = 2 rare meson decays and (d) nuclear muon-positron conversion. In the absence of exotic…
The latest search for the rare kaon decay $K^+\to\pi^+\nu\bar\nu$ by the NA62 experiment has produced evidence for it with a branching fraction consistent with the prediction of the standard model. The new result implies that in this decay,…
We consider a scalar dark matter annihilations to light leptons mediated by charged exotic fermions. The interaction of this model also adds a correction to dipole moments of light leptons. In the simplified model, these processes will…
Major progress has been made in kaon physics in the past 50 years. The number of KL->pi+pi- events has increased by 6 orders of magnitude, and the observed CP violation was experimentally proven to be caused by a complex phase in the CKM…
The deformation of a nucleon embedded in various finite nuclei is considered by taking into account the distortion of the chiral profile functions under the action of an external field representing the nuclear density. The baryon charge…
The observed matter-antimatter asymmetry in the universe is a serious challenge to our understanding of nature. Baryon/lepton number violation (BNV/LNV) decays have been searched for in many experiments to understand this large-scale…
We develop a theory of the EPR-like effects due to neutrino oscillations in the $\pi \to \mu\nu$ decays. Its experimental implications are space-time correlations of neutrino and muon when they are both detected, while the pion decay point…
A linear increase with the volume of the topological susceptibility can signal spontaneous breaking of parity and time inversion, due to a nonzero vacuum expectation value of the topological charge. Such a breaking would produce a nonzero…
Discovering neutrino decay would be strong evidence of physics beyond the Standard Model. Presently, there are only lax lower limits on the lifetime $\tau$ of neutrinos, of $\tau/m \sim 10^{-3}$ s eV$^{-1}$ or worse, where $m$ is the…
Relativistic, kinematically complete phenomenological expressions for the dilepton decay rates of nucleon resonances with arbitrary spin and parity are derived in terms of the magnetic, electric, and Coulomb transition form factors. The…
Baryon number is an accidental symmetry of the Standard Model (SM) Lagrangian that so far has been measured to be exactly preserved, although it is expected to be violated at higher energies. In this work we compute order-of-magnitude…
Relativistic, kinematically complete phenomenological expressions for the dilepton decay rates of nucleon resonances with arbitrary spin and parity are derived in terms of the magnetic, electric, and Coulomb transition form factors. The…
Baryon number is an accidental symmetry of the Standard Model at the Lagrangian level. Its violation is arguably one of the most compelling phenomena predicted by physics beyond the Standard Model. Furthermore, there is a large experimental…
An upper limit for the tau-neutrino mass has been determined from the decay tau -> 5pi+- \nu_tau using data collected with the OPAL detector from 1991 to 1995 in e+e- collisions at \sqrt{s} ~ M_Z. A limit of 43.2 MeV at 95% CL is obtained…
Using 0.8 million D^+D^- pairs collected with the CLEO-c detector at the psi(3770) resonance, we have searched for flavor-changing neutral current and lepton-number-violating decays of D^+ mesons to final states with dielectrons. We find no…
Using a $3.19~\mathrm{fb}^{-1}$ data sample collected at the $\sqrt{s}~=~4.178$ GeV with the BESIII detector, we search for the rare decay $D_{s}^{+} \rightarrow p \bar{p} e^{+} \nu_{e} $. No significant signal is observed, and an upper…
Any theory that have a global spontaneously broken symmetry will imply the existence of very light neutral bosons or massless bosons (sometimes called Majorons). For most of these models we have neutrino-Majoron couplings, that appear as…