Related papers: A note on the moduli-induced gravitino problem
We argue that strong dynamics at the Planck scale can solve the cosmological moduli problem. We discuss its implications for inflation models, and find that a certain type of multi-field inflation model is required for this mechanism to…
In general the gravitino mass and/or the soft supersymmetry breaking masses in the observable sector can be much larger than the TeV scale. Depending on the relation between the masses, new important channels for gravitino production in the…
The most natural way to break the GUT gauge symmetry is with a Higgs field whose vacuum expectation value is of order $10^{16}\,\mbox{GeV}$ but whose mass is of order $10^2$ to $10^3\,\mbox{GeV}$. This can lead to a cosmological history…
We show that the gravitino-overproduction problem is prevalent among inflation models in supergravity. An inflaton field \phi generically acquires (effective) non-vanishing auxiliary field G_\phi, if the K\"ahler potential is non-minimal.…
Most of the inflation models end up with non-vanishing vacuum expectation values of the inflaton fields \phi in the true vacuum, which induce, in general, nonvanishing auxiliary field G_\phi for the inflaton potential in supergravity. We…
Two approaches to the study of cosmological density perturbations in modified theories of Palatini gravity have recently been discussed. These utilise, respectively, a generalisation of Birkhoff's theorem and a direct linearization of the…
We study the dynamics of the standard model Higgs field in the inflationary cosmology. Since metastability of our vacuum is indicated by the current experimental data of the Higgs boson and top quark, inflation models with a large Hubble…
The Hubble constant during the last stages of inflation in a broad class of models based on the KKLT mechanism should be smaller than the gravitino mass, H <~ m_{3/2}. We point out that in the models with large volume of compactification…
Effects of the unstable gravitino on the big-bang nucleosynthesis (BBN) and its implications to particle cosmology are discussed. If the gravitino mass is smaller than \sim 20 TeV, lifetime of the gravitino becomes longer than \sim 1sec and…
Moduli fields are generally present in superstring--inspired models. They are typically characterized by masses of the order of the supersymmetry breaking scale and by interactions of gravitational strength to ordinary matter. If stable,…
A supersymmetric standard model with heavier scalar supersymmetric particles has many attractive features. If the scalar mass scale is O(10 - 10^4) TeV, the standard model like Higgs boson with mass around 125 GeV, which is strongly favored…
Considering gravitino dark matter scenarios, we study constraints on the reheating temperature of inflation. We present the gauge-invariant result for the thermally produced gravitino yield to leading order in the Standard Model gauge…
Gravitational potentials in the cosmos are deeper than expected from observed visible objects, a phenomenon usually attributed to dark matter, presumably in the form of a new fundamental particle. Until such a particle is observed, the jury…
We study moduli-dominated SUSY breaking within the framework of string models. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses. Further gauginos are lighter than…
We consider the modification of Newton's gravity law in Dolgov's higher spin models designed to compensate the cosmological constant. We find that the effective Planck mass is unacceptably large in these models. We also point out that the…
The existence of a dilaton (or moduli) with gravitational-strength coupling to matter imposes stringent constraints on the allowed energy scale of cosmic strings, $\eta$. In particular, superheavy gauge strings with $\eta \sim 10^{16} GeV$…
We show that shape moduli in sub-millimeter extra dimensional scenarios, addressing the gauge hierarchy problem, can dominate the energy density of the universe today. In our scenario, the volume of the extra dimensions is stabilized at a…
We revisit the cosmological viability of the Hu $\&$ Sawicki modified gravity scenario. The impact of such a modification on the different cosmological observables, including gravitational waves, is carefully described. The most recent…
This paper investigates the parameter space of theories with gauge mediated supersymmetry breaking leading to gravitino (cold) dark matter with mass m_{3/2}= 1keV - 10MeV. We pay particular attention to the cosmological role of messenger…
We consider the production of gravitinos and moduli fields from quantum vacuum fluctuations induced by the presence of scalar metric perturbations at the end of inflation. We obtain the corresponding occupation numbers, up to first order in…