The Particle Physics and Cosmology of Supersymmetry and String Theory
Lead Research Organisation:
University of Oxford
Department Name: Oxford Physics
Abstract
In 2010, the Large Hadron Collider (LHC) will begin colliding protons accelerated to close to the speed of light, thus creating conditions that occurred in the universe just after the Big Bang. Experiments at the LHC will explore the origin of mass and search for new symmetries of nature, such as supersymmetry. Cosmological observations are also entering a new era, with the Planck satellite imaging the cosmic microwave background (CMB) and dark energy/dark matter probes such as the Joint Dark Energy Mission (JDEM). The theoretical understanding of supersymmetric theories, such as superstrings and their higher dimensional extension M-theory, has matured to a point where their structure and predictions can be compared with this new data. It is the purpose of this proposal to create an international and interdisciplinary research network, with participating institutions in the UK, the US and Germany, which will explore a wide class of superstring and M-theory constructions and relate them to experimental results from the LHC and to cosmological observations.
Planned Impact
The wider impact of our proposal follows from the synergy of bringing together three disciplines--string theory, mathematics and cosmology--in three different countries, to solve some of the most fundamental problems in modern science, precisely at the time when experimental and observational data will become available. The international component of this proposal is significant, forging a cohesive and reciprocal American and European network'' for interdisciplinary research and education. We view this as a vehicle for enhancing American and European scientific cooperation, as well as a concrete mechanism to train post-doctoral associates and graduate students in a multinational educational environment. The reciprocal nature of this network, that is, simultaneous funding of equivalent proposals in each of the three participating countries, will give American and European students and post-doctoral associates unparalleled opportunities to study, conduct research and attend specialized courses, workshops, conferences and schools organized at our participating universities, Centers, Institute and Laboratory. There is a broad outreach potential by communicating the content of our research to interested non-scientists through public lectures and the media.
Organisations
Publications
Anderson L
(2011)
The Atiyah class and complex structure stabilization in heterotic Calabi-Yau compactifications
in Journal of High Energy Physics
Anderson L
(2012)
Heterotic line bundle standard models
in Journal of High Energy Physics
Anderson L
(2011)
Stabilizing all geometric moduli in heterotic Calabi-Yau vacua
in Physical Review D
Anderson L
(2011)
Stabilizing the complex structure in heterotic Calabi-Yau vacua
in Journal of High Energy Physics
Anderson L
(2014)
A Comprehensive Scan for Heterotic SU(5) GUT models
in Journal of High Energy Physics
Anderson L
(2013)
Vacuum varieties, holomorphic bundles and complex structure stabilization in heterotic theories
in Journal of High Energy Physics
Anderson L
(2015)
Hypercharge flux in heterotic compactifications
in Physical Review D
Anderson L
(2011)
Two hundred heterotic standard models on smooth Calabi-Yau threefolds
in Physical Review D
Anderson L
(2011)
Heterotic standard models from smooth calabi-Yau three-folds
in Proceedings of Science
Braun V
(2012)
The MSSM spectrum from (0,2)-deformations of the heterotic standard embedding
in Journal of High Energy Physics
| Description | - String theory is a theory in 10 dimensions and requires compactification, that is, "curling-up" of six of the 10 dimensions on a very small internal space. This internal space is not unique but can vary in size and shape, degrees of freedom referred to as moduli. Stabilising moduli and thereby selecting an internal space of a certain size and shape is crucial in string compactifications: It is required for a consistent, stable compactification and it determines the values of the coupling constants in the theory. We have made significant progress stabilising the moduli of heterotic compactifications on Calabi-Yau manifolds. - We have shown how to systematically construct heterotic compactifications which lead to the (supersymmetric) standard model of particle physics. Large classes of such compactifications have been found and this is the first time this has been achieved. This work constitutes a significant step towards explaining particle physics from string theory. - We have taken steps to analyse in more detail some of the physical implications of the aforementioned string standard models. In particular, we have addressed the problem of the stability of the proton, the strong CP problem and the problem of why there are precisely three families of quarks and leptons. - F-theory is another corner of string theory and compactifications of F-theory rely on so-called Calabi-Yau four-folds. We have classified such Calabi-Yau four-folds for a specific method of construction, namely complete intersections. We have found about one million topological types and we have worked out many of their topological properties. This database will be a resource and starting point for systematic model building in F-theory. - In a different direction, we have been leading a programme on developing generalised geometry and its extensions as a new geometrical tool for understanding properties of generic supersymmetric flux backgrounds. By extending the tangent space of conventional differential geometry one can obtain a remarkable unified description of generic backgrounds. This potentially opens up a whole new class of compactifications for investigation. - We have showed that, by introducing the analogue of the Levi--Civita connection, generic solutions of both type II supergravity and restrictions of eleven-dimensional supergravity can be described as generalised Ricci flat geometries. This formalism has then also been used to provide a new tool for calculating string corrections to supergravity, and as well as to give a geometrical description of the stringy corrections in the heterotic theory. - Many standard constructions can then be extended to the context of generalised geometry giving new insight into string backgrounds. One important result was to show that the previously mysterious sphere consistent truncations of M-theory and type IIB supergravity could be understood as generalised Scherk--Schwarz compactifications, defining a "Leibniz parallelisation", the natural analogue in generalised geometry of a group manifold. |
| Exploitation Route | Our results lay important groundwork for obtaining a realistic model of particle physics from string theory. The framework of generalised geometry significantly expands the class of potentially realistic compactifications to those with non-trivial fluxes. The work on heterotic moduli stabilisation will hopefully facilitate stabilising all moduli in the context of a quasi-realistic model with the correct particle spectrum. This will then allow for the first meaningful calculation of coupling constants from string theory. String theory is, in principle, capable of explaining the masses of all elementary particles but so far this has not been accomplished explicitly. Our results are an important step towards such an explanation and developing this further is an important future direction. |
| Sectors | Education,Other |
| Description | Result in an extremely abstract and mathematical field such as string theory can clearly not be expected to have a direct economical impact. However, the quest for a "fundamental theory" of physics is clearly of immense cultural importance and is well embedded into the public discourse. The results of this grant have significantly contributed to answering the question whether string theory can be such a fundamental theory and are, therefore, of cultural relevance. |
| Impact Types | Cultural |