Related papers: The Case for an EeV Gravitino
We argue that in the simplest version of the KKLT model, the maximal value of the Hubble constant during inflation cannot exceed the present value of the gravitino mass, H< m_{3/2}. This may have important implications for string cosmology…
In this work, we explore the "degenerate gravitino" scenario where the mass difference between the gravitino and the lightest MSSM particle is much smaller than the gravitino mass itself. In this case, the energy released in the decay of…
Gravitinos are expected to be produced in any local supersymmetric model. Using their abundance prediction as a function of the reheating energy scale, it is argued that the next generation of Cosmic Microwave Background experiments could…
A generic feature of gauge-mediated supersymmetry breaking models is that the gravitino is the lightest supersymmetric particle (LSP). In order not to overclose the universe, the gravitino LSP should be light enough (~ 1 keV), or…
A recent cosmological bound on the gravitino mass, $m_{3/2}<4.7$ eV, together with LHC results on the Higgs mass and direct searches, excludes minimal gauge mediation with high reheating temperatures. We discuss a minimal, vector-mediated…
We review our recent results on dark matter from Starobinsky supergravity. In this context, a natural candidate for Cold Dark Matter is the gravitino. On the other hand, assuming the supersymmetry broken at scales much higher than the…
The gravitino may well play an important role in cosmology, not only because its interactions are Planck-suppressed and therefore long-lived, but also because it is copiously produced via various processes such as particle scatterings in…
Motivated by recent studies of supersymmetry in higher-dimensional spaces, we discuss the experimental signatures of a superlight gravitino, mass < 0.001 eV. We concentrate on the process (e- gamma -> selectronR gravitino) as a probe of…
The lack of evidence for low energy supersymmetry at the LHC implies a supersymmetry scale in excess a TeV. While this is consistent (and even helpful) with a Higgs boson mass at $\approx$ 125 GeV, simple supersymmetric models with scalar…
The presence of high reheating temperatures in the thermal history of the universe challenges supersymmetric scenarios owing to the gravitino problem. We revise a general R-parity conserving gravitino dark matter scenario with a stau as the…
We present a new scenario of gravitino dark matter which is compatible with the thermal leptogenesis. We confirm by an explicit calculation in supergravity that the relic abundance of thermally produced gravitino becomes insensitive to the…
We consider, in the context of the minimal supersymmetric standard model, the case where the gravitino weighs 10^6 GeV or more, which is preferred by various cosmological difficulties associated with unstable gravitinos. Despite the large…
Supersymmetric scenarios where the lightest superparticle (LSP) is the gravitino are an attractive alternative to the widely studied case of a neutralino LSP. A strong motivation for a gravitino LSP arises from the possibility of achieving…
Light gravitinos, with mass in the eV to MeV range, are well-motivated in particle physics, but their status as dark-matter candidates is muddled by early-Universe uncertainties. We investigate how upcoming data from colliders may clarify…
If the gravitino is sufficiently light and stable it will behave as an effective massless neutrino species at the time of nucleosynthesis. Depending on the temperature at which it decouples from the thermal bath in the early universe, the…
It is shown that gravitinos with mass m_{3/2} ~ 0.1-1 MeV may provide suitable cold dark matter candidates in scenarios of gauge mediated supersymmetry breaking (GMSB) under SO(10) grand unification coupled to supergravity, which…
We make use of the phase space density approach to discuss gravitino as a warm dark matter candidate. Barring fine tuning between the reheat temperature in the Universe and superparticle masses, we find that \emph{warm} gravitinos have both…
Gravitinos are a fundamental prediction of supergravity, their mass ($m_{G}$) is informative of the value of the SUSY breaking scale, and, if produced during reheating, their number density is a function of the reheating temperature…
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 an inevitable cosmological consequence in PeV scale SUSY-breaking scenarios. We focus on the SUSY-breaking scale corresponding to the gravitino mass $m_{3/2}=100{\rm eV}-1{\rm keV}$. We argue that the presence of an early…