Related papers: Superparticle Mass Window from Leptogenesis and De…
A new scheme for lightest supersymmetric particle (LSP) dark matter is introduced and studied in theories of TeV supersymmetry with a QCD axion, $a$, and a high reheat temperature after inflation, $T_R$. A large overproduction of axinos…
We study supersymmetric scenarios in which the gluino is the next-to-lightest supersymmetric particle (NLSP), with a mass sufficiently close to that of the lightest supersymmetric particle (LSP) that gluino coannihilation becomes important.…
If the lightest supersymmetric particle (LSP) is Higgsino-like, the thermal relic density is lower than the observed dark matter content for a LSP mass in the sub-TeV region. We outline constraints arising from the Fermi Gamma-Ray Telescope…
We investigate supergravity models in which the lightest supersymmetric particle (LSP) is a stable gravitino. We assume that the next-lightest supersymmetric particle (NLSP) freezes out with its thermal relic density before decaying to the…
It has been widely known that bino-like dark matter in supersymmetric theories suffers from over-production. The situation can be improved if the gluino or wino has a mass of O(10) GeV heavier than the bino, sufficiently reducing the bino…
Present limits on neutrino masses are briefly reviewed, along with cosmological and astrophysical hints from dark matter, solar and atmospheric neutrino observations that suggest neutrino masses. These would imply many possible new…
We investigate the so-called superWIMP scenario with gravitino as the lightest supersymmetric particle (LSP) in the context of non-standard cosmology, in particular, brane world cosmology. As a candidate of the next-to-LSP (NLSP), we…
We study the charged cosmic rays arising from the slow decay of gravitino dark matter within supersymmetric scenarios with trilinear R-parity violation. It is shown that operators of the LLE type can very well account for the recent…
We consider cosmological implications of supersymmetric models with right-handed (s)neutrinos where the neutrino masses are purely Dirac-type. We pay particular attention to the case where gravitino is the lightest superparticle while one…
We study a simple extension of the standard model to simultaneously explain neutrino masses, dark matter and the matter-antimatter asymmetry of the Universe. In our model, the baryon asymmetry is achieved by the leptogenesis mechanism,…
Universe heating in $R^2$-modified gravity is considered. The rates of particle production by the scalaron are calculated for different decay channels. Freezing of massive stable relics with the interaction strength typical for…
Motivated by specific connections to dark matter signatures, we study the prospects of observing the presence of a relatively light gluino whose mass is in the range ~(500-900) GeV with a wino-like lightest supersymmetric particle with mass…
Supersymmetric extensions of the standard model of particle physics assuming the gravitino to be the lightest supersymmetric particle (LSP), and with the next-to-LSP decaying to the gravitino during Big Bang nucleosynthesis, are analyzed.…
We consider the possibility that supersymmetry is broken above the inflationary mass scale and that the only "low" energy remnant of supersymmetry is the gravitino with mass of order the EeV scale. The gravitino in this class of models…
Based on the R-parity violation option of the minimal supersymmetric Standard Model, we examine the scenario where the massive gravitino, relic from the hot big-bang, is the lightest supersymmetric particle and can decay through one or…
We revisit the cosmology of the supersymmetric QCD axion, highlighting the existence of a serious cosmological axino problem that is fully analogous to the gravitino problem of overclosure via thermal production. A general analysis implies…
We study photonic, neutrino and charged particle signatures from slow decays of gravitino dark matter in supersymmetric theories where R-parity is explicitly broken by trilinear operators. Photons and (anti-)fermions from loop and…
We investigate the possibility that the entropy producing decay of a right-handed sneutrino condensate can simultaneously be the source of the baryon asymmetry, of gravitino dark matter, and of cosmological density perturbations. For…
We study the scenario where a sneutrino is the next lightest supersymmetric particle (NLSP) and decays into a gravitino and standard model particles. The daughter particles such as neutrinos and quarks cause electro- and hadronic showers…
It was recently pointed out that in supersymmetric scenarios with gravitino dark matter and bilinear R-parity violation, gravitinos with masses below Mw typically decay with a sizable branching ratio into the 3-body final states W^*+lepton…