The Beecroft Institute Workshop on the Axiverse

Date: 
11 Jan 2013 - 9:30am to 5:00pm
Venue: 
Denys Wilkinson Building, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH
Room: 
Fisher Room
Audience: 
Specialised / research interest

Axions are a well motivated candidate to compose a fraction of the dark matter in the universe as observationally required from cosmological measurements. They are predicted independently as a resolution to the strong CP problem in particle physics. Axion cosmology has a long and fruitful history dating from the 1980's. With the advent of precision cosmology in recent decades it has gained new attention.

Axion like particles are also a generic prediction of string theory, axions being partnered with the moduli of the internal dimensions. It is possible for these axions to be light and stable, providing the QCD axion and its contribution to dark matter, and possibly numerous other candidates with varying properties. The cosmology of these additional candidates has been explored extensively in recent literature, and specific string theory models have been developed where they indeed exist. These additional axions, with their different masses and couplings from the QCD axion are constrained by cosmology via different channels: for example as components of the effective number of relativistic species, or as structure-suppressing dark matter.

The aim of this workshop is to explore what axion cosmology can teach us about fundamental theory in this era of precision cosmological data and sophisticated string theory models for moduli stabilisation.

The workshop will consist of approximately ten half hour talks and aims to explore our ability to make concrete links between phenomenological studies and fundamental theory. What type of information about axions is both accessible from cosmology, and meaningful to high energy theory?

We will focus on the current state of observational cosmology, and how it can give us information about the early universe, and the low temperature universe of today. How can low-energy observations complement high-energy theory? How can cosmological observations bridge the gap between inflationary theory and the late time dark universe? To this end we will discuss use of the CMB, large scale structure and galaxy weak lensing.

We will also focus on the string theory ideas that provide motivations for the study of these problems, and on concrete models recently developed. What sort of picture of cosmic history do we get, including dark matter candidates and production thereof? We will discuss the number of axions expected in these theories, their masses, and decay constants.

We will focus on the axions as dark matter in conjunction with other candidates. What distinguishes axions from WIMPs observationally? What about extra relativistic species?

Finally we will ask to what extent these models can be informed by terrestrial and astrophysical experiments, such as stellar cooling and light-shining-through-a-wall.

The list of confirmed speakers includes:

B. Acharya: The M-theory axiverse
M. Cicoli: Axions and Dark Radiation in type IIB string models
M. Amin: Inflaton and Axion Oscillons
D. J. E. Marsh: Axion isocurvature and inflation
J. Dunkley: Modern observational cosmology
E. Copeland: String cosmology
C. Burrage: Axion-like particles from dark energy models with screening mechanisms
A. Ringwald: Terrestrial tests of the axiverse
L. Amendola: Observables and unobservables in dark energy cosmologies
J. Conlon: Dark Radiation in the Large Volume Scenario

This workshop is organize by Pedro G. Ferreira (Oxford) and David Marsh (Perimeter). It will run all day with lunch provided. We will restrict numbers to, at most, 35 people.

For more information contact: 
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