Astrophysics

I will discuss recent results from the Cosmic Shear component of the CFHT Legacy Survey. These results reach very large scales, allowing a measurement of poper spectrum of matter fluctuations in the linear regime, and of cosmological parameters.

We study the necessary and sufficient topological conditions for general Calabi-Yaus to get a non-supersymmetric AdS exponentially large volume minimum of the scalar potential in flux compactifications of IIB string theory. It turns out that string loop corrections play a crucial role to realise exponentially large volume minima for fibration Calabi-Yaus and to stabilise 4-cycles which support chiral matter. The robustness of these results is due to the \'extended no-scale structure\': for arbitrary Calabi-Yaus, the leading contribution of these corrections to the scalar potential is always vanishing. We use the Coleman-Weinberg potential to motivate this cancellation from the viewpoint of low-energy field theory.

An electroweak singlet coupling through the Higgs portal has a natural mass scale $m_Ssim m_h$. In this mass range its annihilation cross section is dominated by proximity to the $W$, $Z$ and Higgs peaks. Analysis of the $gamma$ ray signal from electroweak singlet annihilation in the mass range $80,mathrm{GeV}

Proton structure measurements at high $Q^{2}$ performed by the H1 and ZEUS collaborations at the HERA collider, are reviewed. Neutral and charged current deep inelastic scattering cross sections and structure functions are presented. The review also discusses improvements to the parton density measurements using jet cross section data and recent high $Q^{2}$ inclusive cross section measurements.

It was proposed recently that type IIB orientifold compactifications on CY(3) in the presence of fluxes exhibit an attractor mechanism similar to the one in black hole physics, in other words that minimizing the relevant scalar potential is equivalent to solving a system of attractor equations. So far this conjecture has been verified only numerically. We show by analytical means that the conjectured susy attractor equations do indeed give supersymmetric minima of the relevant scalar potential. Furthermore, we obtain attractor equations for the most general N=1 flux compactifications of type IIA/B string theory, namely compactifications on SU(3)xSU(3) structure spaces.

Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental \'constants\' in expanding Universe. The spatial variation can explain fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. I present a review of works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses (Higgs vacuum). There are some hints for the variation in quasar absorption spectra and Big Bang nucleosynthesis data. A very promising method to search for the variation consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transitions between very close atomic, nuclear and molecular energy levels. Large enhancement also happens in nuclear, atomic and molecular collisions near resonances. How changing physical constants may occur? Light scalar fields very naturally appear in modern cosmological models, affecting parameters of the Standard Model (e.g. alpha). Cosmological variations of these scalar fields should occur because of drastic changes of matter composition in Universe: the latest such event is rather recent (about 5 billion years ago), from matter to dark energy domination. Massive bodies can also affect physical constants. The strongest limits are obtained from the measurements of dependence of atomic frequencies on the distance from Sun (the distance varies due to the ellipticity of the Earth\'s orbit).