Related papers: Invisible widths of heavy mesons
We study the implications of phenomenological processes on a two-singlet extension of the Standard Model we introduced in a previous work to describe light cold dark matter. We look into the rare decays of $\Upsilon $ and $B$ mesons, most…
Heavy neutral leptons are predicted in many extensions of the Standard Model with massive neutrinos. If kinematically accessible, they can be copiously produced from kaon and pion decays in atmospheric showers, and subsequently decay inside…
We review the particle physics aspects of neutrino-less double beta decay. This process can be mediated by light massive Majorana neutrinos (standard interpretation) or by something else (non-standard interpretations). The physics potential…
Invisible decays of neutral hadrons are evaluated as ordinary-mirror particle oscillations using the newly developed mirror matter model. Assuming equivalence of the $CP$ violation and mirror symmetry breaking scales for neutral kaon…
Neutrinoless double beta decay pops up almost in any extension of the standard model. It is perhaps the only process, which can unambiguously determine whether the massive neutrinos are Majorana or Dirac type particles. In addition from the…
The mass spectrum of the kaon family is analyzed by the {modified} Godfrey-Isgur model with a color screening effect approximating the kaon as a heavy-light meson system. This analysis gives us the structure and possible assignments of the…
Light extra U(1) gauge bosons, so called hidden photons, which reside in a hidden sector have attracted much attention since they are a well motivated feature of many scenarios beyond the Standard Model and furthermore could mediate the…
Mesons with masses below their lowest OZI-allowed strong-decay thresholds have very small widths. Thus, it is usually believed that they can be safely treated as pure quark-antiquark bound states in spectroscopy models. However, unitarised…
The recently observed diphoton anomaly at the LHC appears to suggest the presence of a rather broad resonance. In this note, it is pointed out that this does not hold if the two photons are produced along with an extra state. Specifically,…
The existence of light sterile neutrinos, as predicted in several models, can help to explain a number of observations starting from dark mater to recent anomalies in short baseline experiments. In this paper we consider two models -…
We construct two new classes of models for double beta decay, each of which leads to an electron spectrum which differs from the decays which are usually considered. One of the classes has a spectrum which has not been considered to date,…
The impact a new neutral light particle of spin 0, 1/2, 1, or 3/2 could have on the tiny width of a light Higgs boson is systematically analyzed. To this end, we include all the relevant effective interactions, whether renormalizable or…
That massless dark photons could exist and have flavor-changing magnetic-dipole interactions with down-type light quarks is an attractive possibility which may be realized in various new-physics scenarios. It is potentially testable not…
The Standard Model (SM) plus a real gauge-singlet scalar field dubbed darkon (SM+D) is the simplest model possessing a weakly interacting massive particle (WIMP) dark-matter candidate. In this model, the parameters are constrained from dark…
Masses and decay constants of scalar $D_0$ and $D_{s0}$ mesons in isospin asymmetric strange hadronic matter at finite temperature are evaluated using QCD sum rules and chiral SU(3) model. In-medium light quark condensates, $\left\langle…
The measurement of the invisible Z-boson decay width at e+e- colliders can be done "indirectly", by subtracting the Z-boson visible partial widths from the Z-boson total width, or "directly", from the process e+e- -> \gamma \nu \bar{\nu}.…
We study the heavy-light mesons within basis light-front quantization. The resulting mass spectra of $D$, $D_s$, $B$, and $B_s$ agree reasonably well with experiments. We also predict states which could be measured in the near future. In…
An introduction to physics of in-medium hadrons with special emphasis towards modification of vector meson properties in dense nuclear matter is given. We start from remarkable analogy between the in-medium behavior of atoms in gases and…
A model independent parametrization of an extension of the Standard Model including vector-like quarks, new heavy gauge bosons and an extra scalar, is introduced. Theoretical constraints on the model couplings and hypothetical particle…
All extensions of the standard model that generate Majorana neutrino masses at the electro-weak scale introduce some "heavy" mediators, either fermions and/or scalars, weakly coupled to leptons. Here, by "heavy" we understand implicitly the…