Related papers: An anthropic solution to the cosmological moduli p…
We consider a cosmologically consistent scenario with a heavy Polonyi field. The Polonyi field with a mass of ${\cal O}(100){\rm\,TeV}$ decays before the Big-Bang Nucleosynthesis (BBN) and avoids the severe constraint from the BBN. However,…
We point out that the cosmological moduli problem is not necessarily resolved even if the modulus mass is heavier than O(10)TeV, contrary to the common wisdom. The point is that, in many scenarios where the lightest moduli fields are…
Light scalar fields with only gravitational strength couplings are typically present in UV complete theories of physics beyond the Standard Model. In the early universe it is natural for these fields to dominate the energy density, and…
We consider the phenomenological consequences of fixing compactification moduli. In the simplest KKLT constructions, stabilization of internal dimensions is rather soft: weak scale masses for moduli are generated, and are of order m_\sigma…
One proposed solution of the moduli problem of string cosmology requires that the moduli are quite heavy, their decays reheating the universe to temperatures above the scale of nucleosynthesis. In many of these scenarios, the moduli are…
In superstring theories, there exist various dilaton and modulus fields which masses are expected to be of the order of the gravitino mass $m_{3/2}$. These fields lead to serious cosmological difficulties, so called ``cosmological moduli…
Standard Big Bang nucleosynthesis at baryonic density as inferred by WMAP implies a primordial Li7 abundance factor of two to three larger than that inferred by observations of low--metallicity halo stars. Recent observations of Li6 in halo…
We address the cosmological moduli/gravitino problems and the issue of too little thermal but excessive non-thermal dark matter from the decays of moduli. The main examples we study are the G2-MSSM models arising from M theory…
The standard cosmological model, LCDM, provides an excellent fit to Cosmic Microwave Background (CMB) data. However, the model has well known problems. For example, the cosmological constant, is fine-tuned to 1 part in 10^100 and the cold…
Many models of supersymmetry breaking involve particles with weak scale mass and Planck mass suppressed couplings. Coherent production of such particles in the early universe destroys the successful predictions of nucleosynthesis. We show…
Supersymmetric models accompanied by certain anomaly-free discrete R-symmetries Z_n^R are attractive in that 1. the R-symmetry (which can arise from compactified string theory as a remnant of the broken 10-d Lorentz symmetry) forbids…
The physics of moduli fields is examined in the scenario where the gravitino is relatively heavy with mass of order 10 TeV, which is favored in view of the severe gravitino problem. The form of the moduli superpotential is shown to be…
If one simultaneously invokes the SUSY solution to the gauge hierarchy problem and the PQ solution to the strong CP problem, then one might expect mixed axion/neutralino dark matter (DM), i.e. two dark matter particles. In this case, dark…
The string axion may provide the most attractive solution to the strong CP problem in QCD. However, the axion energy density easily exceeds the dark matter density in the present universe due to a large decay constant around $10^{16}$ GeV,…
If moduli, or other long-lived heavy states, decay in the early universe in part into light and feebly interacting particles (such as axions), these decay products could account for the additional energy density in radiation that is…
At present, the Standard Model (SM) agrees with almost all collider data. Yet, three finetuning issues -- the Higgs mass problem, the strong CP problem and the cosmological constant problem -- all call for new physics. The most plausible…
Cosmological constraints on moduli, whose coupling to matter is stronger than Planck mass suppressed coupling, are derived. In particular, moduli are considered to be produced by oscillating loops of cosmic strings and constraints are…
We study a scenario for baryogenesis in modular cosmology and discuss its implications for the moduli stabilization mechanism and the supersymmetry (SUSY) breaking scale. If moduli fields dominate the Universe and decay into the standard…
Many models of supersymmetry breaking, in the context of either supergravity or superstring theories, predict the presence of particles with Planck-suppressed couplings and masses around the weak scale. These particles are generically…
The lack of evidence for weak scale supersymmetry from LHC Run-I and Run-II results along with null results from direct/indirect dark matter detection experiment have caused a paradigm shift in expected phenomenology of SUSY models. The…