Related papers: Constraining $\alpha_s(M_Z)$ from the Hidden Secto…
Effective theories with the matter content of the minimal supersymmetric Standard Model below the string scale M_string predict a wrong value for the weak--mixing angle sin^2\theta_W and strong coupling constant \alpha_S at the scale M_Z.…
We examine the issue of fine tuning in the MSSM with GUT-scale boundary conditions. We identify specific unification patterns and mass relations that can lead to a significant lowering of the fine tuning due to gauginos, scalars, and the…
We have developed a concept of parallel existence of the ordinary (O) and hidden (H) worlds with a superstring-inspired E_6 unification, broken at the early stage of the Universe into SO(10) X U(1) - in the O-world, and SU(6)' X SU(2)' - in…
The multi-sector SUSY breaking predicts the existence of pseudo-goldstino, which could couple more strongly to visible fields than ordinary gravitino. Then the lightest neutralino and chargino can decay into a pseudo-goldstino plus a…
A growing neutrino mass can stop the dynamical evolution of a dark energy scalar field, thus explaining the 'why now' problem. We show that such models lead to a substantial neutrino clustering on the scales of superclusters. Nonlinear…
In the cold dark matter scenario, dark matter halos are assembled hierarchically from smaller subunits. Some of these subunits are disrupted during the merging process, whereas others survive temporarily in the form of subhalos. A…
Neutralino dark matter is well motivated, but also suffers from two shortcomings: it requires gravity-mediated supersymmetry breaking, which generically violates flavor constraints, and its thermal relic density \Omega is typically too…
The EDGES Collaboration has recently reported the detection of a stronger-than-expected absorption feature in the global 21-cm spectrum, centered at a frequency corresponding to a redshift of z ~ 17. This observation has been interpreted as…
We present a unified model of dark matter and dark energy. The dark matter field is a modulus corresponding to a flat direction of supersymmetry, which couples, in a hybrid type potential, with the dark energy field. The latter is a light…
In a generic Grand Unified Theory with a relatively small dispersion of the spectrum around the $Z$-boson and the unification masses, a connection is established, exact at one loop level, between $M_Z$, $G_{\rm F}$, $\alpha(M_Z)$ and the…
To reveal the galactic dark matter in the form of MACHOs ("Massive Astrophysical Compact Halo Objects"), the POINT-AGAPE collaboration is carrying out a search for gravitational microlensing towards M31. A clear microlensing signal is…
Higgsinos can be the lightest supersymmetric particles, allowing for either a full or partial dark matter interpretation, with the correct thermal freeze-out abundance obtained for masses near 1.1 TeV. Dark matter direct detection…
We investigate the stability of the hidden sector gaugino condensate in a SL(2,Z)-invariant supergravity model inspired by the E8*E8 heterotic string, using the chiral superfield formalism. We calculate the Planck-suppressed corrections to…
SUSY models with a modified dark sector require constraints to be reinterpreted, which may allow for scenarios with low tuning. A modified dark sector can also change the phenomenology greatly. The addition of the QCD axion to the Minimal…
If the dark matter is part of a hidden sector with only very feeble couplings to the Standard Model, the lightest particle in the hidden sector will generically be long-lived and could come to dominate the energy density of the universe…
Light moduli fields in string compactifications can have interesting implications for particle physics and cosmology. Fifth force bounds impose stringent constraints on the interactions of such moduli with the visible sector. To be…
If the hidden sector contains more than one U(1) groups, additional dim-4 couplings (beyond the kinetic mixing) between the massive U(1) fields and the hypercharge generally appear. These are of the form similar to the Chern-Simons…
The MSSM candidates arising from the heterotic MiniLandscape feature a very constrained supersymmetry breaking pattern. This includes a fully predictable gaugino mass pattern, which is compressed compared to the CMSSM, and an inverted…
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…
We consider the neutralino proton cross section for detection of Milky Way dark matter for a number of supergravity models with gauge unification at the GUT scale: models with universal soft breaking (mSUGRA), models with nonuniversal soft…