22-26 August 2011, Porto, Portugal
Supergravity and inflationary cosmology
This talk will discuss various aspects of non-decoupling in inflationary cosmology, in particular the (observable) effects of very heavy fields present during inflation. There is recent progress in understanding slow roll inflation with sharp turns, which is generic in Supergravity and Superstring models. The primordial perturbations show features in the power spectrum and non-gaussianities that are correlated and potentially detectable. This opens the possibility to detect fields much heavier than the scale of inflation in the next generation of cosmic microwave background observations.
SUSY at the LHC
Supersymmetric theories of particle physics fix a host of problems in the Standard Model, while receiving some indirect support from experiment. They predict a host of new matter states many of which ought to be accessible to CERN LHC searches. They also allow for at least four cold dark matter (CDM) candidates: 1. the lightest neutralino (a WIMP), 2. the gravitino (a superWIMP), 3. the axino, (superpartner to the axion) and 4. a sneutrino. I review the latest searches for SUSY from Atlas and CMS, and what these imply for supersymmetric theories and the dark matter of the universe.
Good Things from Brane Back-reaction
In a nutshell brane physics has had two lesson for those who worry about naturalness problems and hierarchies: having a low gravity scale reduces ultraviolet sensitivity (think large extra dimensions); and brane back-reaction can be important (think warping and Randall-Sundrum models). But the effects of back-reaction are largely unexplored, apart from for codimension-1 branes (think again of Randall Sundrum models), and one dimension rarely gives a good indication of what can be expected from higher dimensions. This talk summarizes recent progress on understanding back-reaction for higher codimension branes, together with some interesting new implications they can have for particle physics and cosmology.
Beyond standard WIMPs
The identification of dark matter is one of the most important problem of modern cosmology. I will talk about the candidates of dark matter beyond standard WIMPs, especially for the gravitino and axino dark matter and its relation to the early Universe and collider experiments.
Dark energy theory
Abstract not yet available.
Cosmic magnetic fields
I shall review the possibilities to generate the cosmological seeds of the magnetic fields observed in galaxies and cluster in the early Universe. Besides the generation of magnetic fields with sufficient large scale structure during inflation or during phase transitions in the early Universe, I shall discuss the possibility to detect them in the cosmic microwave background or by the gravitational wave background they generate. I shall also mention new observational lower limits on intergalactic magnetic fields and the challenge these represent for the hypothesis that magnetic fields are generated at late time during the process of galaxy formation.
Dark Matter Theory in Light of Recent Searches
Theoretical particle physics has provided a number of compelling candidates for dark matter particles. After a brief review of the possibilities, I will focus on the best-motivated among them: Weakly Interacting Massive Particles. Excitement pervades the community because of anomalous results in a variety of experiments worldwide that may be hints of detection; these include both direct (DAMA, COGENT) and indirect detection (PAMELA, HEAT, FERMI) experiments. If the current hints of detection are right, then theorists are forced to rethink the simplest models of WIMP interactions with ordinary matter. Upcoming experiments should be able to conclusively test the WIMP hypothesis in the coming decade. Another approach to dark matter searches would be the discovery of dark stars, a phase of stellar evolution in which early stars are powered by dark matter annihilation.
Reheating after Inflation
In this talk I will give a general review of the present status on the theory of preheating and reheating after inflatior, as well as the phenomenological signatures we may detect in the future from a gravitational wave background, cosmological magnetic fields and baryogenesis.
Big Bang Nucleosynthesis and the Cosmological Lithium Problem
The light elements of 2H, 3He, 4He, and 7Li are synthesized in appreciable amounts during the hot Big Bang between ~ 1-1000 seconds. A comparison between observationally inferred and theoretically predicted abundances of these light elements may be used to meaningfully constrain the conditions of the early Universe and physics beyond the standard model of particle physics. Within the standard Big Bang nucleosynthesis scenario at baryon density as given by WMAP this comparison is in agreement for 2H, inconclusive for 3He and 4He, and significantly discrepant for 7Li. Astrophysical and physics beyond the standard model solution to this cosmological 7Li problem are discussed. A possible cosmological 6Li problem is also highligthed.
Update on neutrino cosmology
I will review the constraints on neutrino abundances, masses, chemical potentials and other neutrino properties, based on available cosmological data. I will also summarize progresses in modelling and computing the impact of neutrinos on cosmological observables, including in the non-linear regime. Finally I will discuss the possible impact of future data on neutrino parameter extraction.
After presenting the motivation for using string theory to describe the very early universe, I will review recent attempts to realize inflation, or an alternative to inflation, in string theory.
Direct Dark Matter Searches
The existence of some missing matter in the universe was first postulated about 80 years ago. Since then we have collected very striking evidences for the existence of the so called dark matter, but it's nature remains unknown. Weakly Interacting Massive Particles are one of the most promising candidates for dark matter, and multiple experiments around the world are trying to detect them through the observation of its elastic interaction with target nuclei. In this talk we will review the challenges for any direct dark matter search and the latest results of the different direct dark matter experiments currently working.
The equivalence principle and the quest for new physics
I will emphasize the role of the equivalence principle (EP) for modeling and testing the physics beyond General Relativity and the Standard Model and outline its present experimental status. Violations of the EP are in fact predicted by string-inspired scenarios and models of dark energy/modified gravity in which light degrees of freedom couple to ordinary matter. Finally, I will mention a recent attempt to modify General Relativity at large distances by enforcing an even stronger version of the EP.
An overview of the phenomenology and observational status of inflation wll be given with particular emphasis on the theoretical challenges we might be facing the next few years.
Dark matter indirect detections
Weakly interacting and massive particles (WIMP) have been suggested as plausible candidates to the astronomical dark matter (DM). Should these putative species exist, they would continuously annihilate within the Milky Way halo and yield rare antimatter particles - such as antiprotons and positrons - as well as high-energy gamma-rays and neutrinos.
Some of the most stringent tests of the standard inflationary cosmology relate to its statistical properties beyond the power spectrum: primordial fluctuations are predicted to deviate from Gaussianity by less than 1 part in a million. New high resolution experiments will place standard inflation firmly in the dock, especially forthcoming data from the Planck satellite survey of the cosmic microwave background (CMB). I will describe new modal estimator methods which allow the efficient and optimal extraction of higher order correlators (the bispectrum and trispectrum) from these large datasets. I will review current polyspectra constraints from the WMAP CMB maps and forecasts for Planck, as well as applications to large-scale structure. I will discuss future prospects for uncovering non-Gaussian signatures of new physics from the early universe.
Modifications of General relativity and the equivalence principle
Most extensions of general relativity involve a violation of the equivalence principle, either in its weak or strong form. The relations between the local position invariance and the universality of free fall will be reviewed, as well as the progresses to test the equivalence principle on astrophysical scales, using fundamental constants. Mechanisms aiming at "hiding" these violations and the link with dark energy models will be discussed.
The standard cosmological model, the so called LCDM model, is specified by 6 basic cosmological parameters. The precision on their value has steadily improved over the years with new data and observations. More recently the focus has shifted towards modeling, and constraining or detecting possible deviations from the standard cosmological model. While for many physically motivated deviations it is relatively easy to find a suitable parameterization, add new parameters to be basic 6 and constrain these extra cosmological parameters, there are many interesting possible deviations with are not straightforwardly described by few extra cosmological parameters. It is nevertheless a interesting avenue as deviations from the LCDM model have deep implications with and connection to fundamental physics. I will briefly review the status of cosmological parameters determination and show some examples of testing deviations from the standard cosmological model.
The fine-scale structure of dark matter halos
At the time of recombination, 400,000 years after the Big Bang, the structure of the dark matter distribution was extremely simple and can be inferred directly from observations of structure in the cosmic microwave background. At this time dark matter particles had small thermal velocities and their distribution deviated from uniformity only through a gaussian field of small density fluctuations with associated motions. Later evolution was driven purely by gravity and so obeyed the collisionless Boltzmann equation. This has immediate consequences for the present distribution of dark matter, even in extremely nonlinear regions such as the part of the Galaxy where the Sun resides. I will show how this structure can be followed in full generality by integrating the Geodesic Deviation Equation in tandem with the equations of motion in high-resolution N-body simulations, enhancing their effective resolution by more than 10 orders of magnitude, and permitting a detailed treatment of annihilation radiation from caustics within LCDM halos. I will also discuss how the predicted distribution at the Sun's position impacts the expectations for laboratory experiments seeking to detect the dark matter directly, in particular, the possibility of extremely narrow line signals that may be visible in axion detectors.
I review the role of the QCD axion in cosmology as a potential dark matter candidate, and discuss current cosmological and astrophysical constraints on axions and axion-like particles.