String Phenomenology 2012
Monday 25th June 2012 to Friday 29th June 2012
09:00 to 09:30  Registration  
09:30 to 09:35  Welcome  INI 1  
09:35 to 10:10 
Phenomenological Targets for String Model Builders
We shall detail points of interest for string model builders coming from recent data, providing some targets that model builders may like to hit.
In particular, we shall discuss higgs and supersymmetry searches, and infer some general statements about the spectra and naturalness of models. We shall also mention the t tbar asymmetry from the Tevatron, which disagrees with Standard Model expectations, recent relevant B decay results, Daya bay implications for neutrino masses and mixings and an inferred 130 GeV line in gamma rays coming from our galaxy.

INI 1  
10:10 to 10:45 
Generic String/M theory Predictions for Particle Physics and Dark Matter
Solutions of string/M theory with low energy supersymmetry have moduli fields with masses which are generically of order the mass of the gravitino. This leads to a spectrum of superpartners with squarks and sleptons just beyond the LHC energy scale. Gluinos could however be produced at the LHC and decay with top and bottom rich final states. The mass of the lightest Higgs boson is predicted to be between 122 and 129 GeV. The moduli fields dominate the preBBN Universe leading to a nonthermal history which significantly impacts our picture of dark matter, which is predicted to have two components: axions and Wino like WIMPS. The tentative high energy photon signal in the FermiLAT data can be successfully interpreted as the annihilation of these WIMPs into the Zboson and a photon. Moreover, we demonstrate that this signal is also consistent with an approximately 50% axion component. The axion component implies that experiments like Planck will NOT observe tensor modes in the CMB.

INI 1  
10:45 to 11:20  Morning Coffee  
11:20 to 11:55 
K Choi (Korea Advanced Institute of Science and Technology (KAIST)) Cosmological moduli problem and double thermal inflation in large volume scenario 
INI 1  
11:55 to 12:30 
Open string axions and the flavor problem
I will describe some bottom up models of particle physics inspired by Dbrane phenomenology that address aspects of the flavor problem. I will argue that many of these models lead to an axion arising from open string modes that sometimes falls within the allowed axion window. The phenomenology of these axion models can rule out many models of physics beyond the standard model. A satisfactory solution of the flavor problem seems to produce models that deconstruct extra dimensions.

INI 1  
12:30 to 13:30  Lunch at Wolfson Court  
14:00 to 14:35 
Cosmology and Moduli Stabilisation for Chiral Global Models
I will present recent results which try to combine moduli stabilisation and chiral model building both in the geometric regime and at the quiver locus within a fully consistent type IIB string compactification described in terms of toric geometry. I will also briefly discuss some cosmological applications and a new way to get dS vacuua in a manifestly supersymmetric effective action.

INI 1  
14:35 to 15:10 
Looking for the LARGE volume axiverse
An "axiverse" is a generic prediction of string theory, although the axions are typically extremely hard to detect, and sometimes may not actually solve the strong CP problem. I shall discuss how the axiverse is realised in the LARGE volume scenario, including what the axion couplings are, whether they can be detected, how the QCD axion can arise  and also how to build models with an additional axionlike particle that could explain some intriguing astrophysical anomalies.

INI 1  
15:10 to 15:45 
Weakly interacting slim particles in astrophysics, cosmology and the laboratory
Weakly interacting slim particles (WISPs) appear often in extensions of the standard model, string theory in particular. This is the case of pseudo Nambu Goldstone Bosons, stringy axions, moduli, hidden photons, minicharged particles and a long etc. The strongest bounds on their existence come frequently from cosmology and astrophysics but, in particular cases, laboratory experiments at the low energy, high intensity frontier, are more relevant. In this talk we review the most relevant astro/cosmo arguments and laboratory experiments used to constrain the existence of WISPs, focusing on the most discussed cases of axionlike particles (ALPs) and Hidden Photons. We will also pay attention to the recent anomalies which could be pointing to the existence of WISPs: the anomalous cooling rate of white dwarfs and the transparency of the Universe to gammarays. Finally, we will conclude discussing WISPs as testable cold dark matter candidates.

INI 1  
15:45 to 16:20  Afternoon Tea  
16:20 to 16:55 
D Luest (MaxPlanckInstitut für Physik, München) Noncommutative/nonassociative geometry and effective actions of nongeometric string backgrounds 
INI 1  
16:55 to 17:30 
R Blumenhagen (MaxPlanckInstitut für Physik, München) Strings in Nongeometric Backgrounds
We consider closed bosonic string theory with flat background and constant Hflux. Up to linear order in the flux, this is a solution to the string equations of motion and we are able to define a worldsheet conformal field theory framework to compute scattering amplitudes. In the easiest cases of npoint tachyon amplitudes, we use the properties of the Rogers dilogarithm function to speculate about the nature of the product of functions on spacetimes Tdual to the original configuration.

INI 1  
17:30 to 18:45  Drinks Reception  
18:45 to 19:15  Dinner for Residents at Fitzwilliam & Churchill Colleges 
09:00 to 09:35 
S Raby (Ohio State University) SU(6) orbifold GUT on M4 x RP2 : Gauge  Higgs unification
In a recent paper we constructed an SU(6) N=2 SUSY model in 6 dimensions. We discuss gauge and SUSY breaking via orbifolding and/or Wilson lines. The model has gaugeHiggs unification. We calculate the GUT scale threshold corrections to gauge coupling unification.

INI 1  
09:35 to 10:10 
Supersymmetric unification and R symmetries
After reviewing some virtues and problems of the minimal supersymmetric standard model (MSSM), I will show that, if one demands anomaly freedom and fermion masses, only R symmetries can forbid the supersymmetric Higgs mass term mu. I will then prove that R symmetries are not available in conventional grand unified theories (GUTs) and argue that this prevents natural solutions to the doublettriplet splitting problem in four dimensions. On the other hand, higherdimensional GUTs do not suffer from this problem. I will briefly discuss an explicit stringderived model in which the mu and dimension five proton decay problems are solved by an order four discrete R symmetry, and comment on the higherdimensional origin of this symmetry.

INI 1  
10:10 to 10:45 
P Nilles (Universität Bonn) The Zip Code of Quarks, Leptons and Higgs Bosons
The location of particles in extra dimensions determines the properties of the 4dimensional lowenergy effective action, such as Yukawa couplings and the pattern of supersymmetry breakdown. We analyze these questions in the framework of the heterotic MiniLandscape.

INI 1  
10:45 to 11:20  Morning Coffee  
11:20 to 11:55 
B Nelson (Northeastern University) An Algorithmic Method for Identifying Swiss Cheese Manifolds
We describe an efficient algorithmic test for the Swiss Cheese property in CalabiYau threefolds, which is typically considered in the context of moduli stabilization in Large Volume Scenarios of type~IIB flux compactifications of string theory. The algorithm recasts the issue of moduli stabilization at large volume into the language of algebraic geometry, thereby allowing for a large scale computational analysis. Preliminary results of a scan of CalabiYau three folds with small Hodge numbers will be presented.

INI 1  
11:55 to 12:30  Compactified string/M theory prediction of the Higgs boson mass and properties.  INI 1  
12:30 to 13:30  Lunch at Wolfson Court  
14:00 to 14:15 
Nongeometric fluxes in higher dimensions: I
Nongeometric fluxes appear in fourdimensional gauged supergravities through specific terms in the potential. These terms are of phenomenological interest for the matters of moduli stabilization or de Sitter solutions. Unfortunately, their tendimensional origin, and their relation to nongeometry, remain unclear. In this talk, I will present recent progress on these questions. Thanks to a field redefinition in tendimensional supergravity, one makes the nongeometric Q and R fluxes appear, and additionally restores a standard notion of geometry. A dimensional reduction can then be performed, and the fourdimensional nongeometric terms of the scalar potential are recovered.

INI 1  
14:00 to 14:15 
Y Sumitomo (Hong Kong University of Science and Technology) A Stringy Mechanism for A Small Cosmological Constant
We propose a simple stringy mechanism that prefers metastable vacua with a small cosmological constant. We argue the generic probability distribution for the metastable vacua which peaks with a divergent behavior at the zero value of cosmological constant. Then we illustrate this in a model of type IIB string theory, though the suppression in the model is modest.

INI 2  
14:15 to 14:30 
Nongeometric fluxes in higher dimensions: II
It has been shown that nongeometric fluxes appear in tendimensional supergravity by performing a field redefinition. Following a similar strategy in double field theory surprisingly allows for a geometric interpretation of these fluxes. More precisely, the Qflux appears as part of a dual curvature scalar, reminiscent of the geometric flux f. The Rflux turns out to be a tensor and appears in the same way as the usual Hflux does. Solving the strong constraint connects this formalism to the tendimensional approach. Furthermore, some recent lifts of fourdimensional gauged supergravity to double field theory can be matched.

INI 1  
14:15 to 14:30 
Accelerating Universes in String Theory via Field Redefinition
We study cosmological solutions in the effective heterotic string theory with \alpha'correction terms in string frame. It is pointed out that the effective theory has an ambiguity via field redefinition and we analyze generalized effective theories due to this ambiguity. We restrict our analysis to the effective theories which give equations of motion of second order in the derivatives, just as ``Galileon" field theory. This class of effective actions contains two free coupling constants. We find de Sitter solutions as well as the powerlaw expanding universes in our fourdimensional Einstein frame. The accelerated expanding universes are always the attractors in the present dynamical system.

INI 2  
14:30 to 14:45 
P Smyth ([EPFL  Ecoles Polytechniques Fédérales de Lausanne]) Spontaneous Partial Supersymmetry Breaking
I will review some recent work on spontaneous partial supersymmetry breaking in extended supersymmetry. I will first describe the nogo theorems which forbid N=2 to N=1 spontaneous supersymmetry breaking in global and local supersymmetry, before showing how they are circumvented. I will then discuss some new techniques involving the embedding tensor formalism which allow us to study this problem systemically and find the lowenergy effective theory in the N=1 vacuum. This leads to interesting insights into spontaneous partial supersymmetry breaking in supergravity and string theory, as well as new results in quaternionic geometry.

INI 1  
14:30 to 14:45 
Nflation and Noboundary measure
In this talk, I will give a brief review on Nflation models. Moreover, I will present the recent work of Nflation with noboundary condition which is one of several ways to avoid the singularities of our very early Universe. Even though noboundary measure disfavours the histories of large efoldings in inflation, we show another way to lift up the probability of inflationary histories without considering any other factors, but with the large number of fields such as Nflation fields.

INI 2  
14:45 to 15:00  Break  
15:00 to 15:15 
Bianchi identities for nongeometric fluxes from PalatiniLovelockCartan gravity
Flux compactifications are an important building block for obtaining (semi)realistic string theory vacua. Conventional H and geometric flux are rather wellunderstood in this setting, however, nongeometric fluxes are understood to a far lesser degree.
In this talk, it is first reviewed how certain fluxes can be treated as the torsion of a connection, and how gravity theories can be formulated via the Palatini formalism. Next, this formalism is extended to higher orders in the curvature leading to constraints on the fluxes, which are then interpreted as Bianchi identities.

INI 1  
15:00 to 15:15 
De Sitter vacua in type IIB / Ftheory by Kahler uplifting
We derive a sufficient condition and present explicit examples based on toric geometry for realizing metastable de Sitter vacua with small positive cosmological constant within type IIB string theory / Ftheory flux compactifications with spontaneously broken supersymmetry. There are a number of `lamp post' constructions of de Sitter vacua in type IIB string theory and supergravity. We show that one of them  the method of `K\"ahler uplifting' by Fterms from an interplay between nonperturbative effects and the leading $\alpha'$correction  allows for a more general parametric understanding of the existence of de Sitter vacua. The result is a condition on the values of the flux induced superpotential and the topological data of the CalabiYau compactification, which guarantees the existence of a metastable de Sitter vacuum if met. Our analysis explicitly includes the stabilization of all moduli, i.e. the K\"ahler, dilaton and complex structure modu li, by the interplay of the leading perturbative and nonperturbative effects at parametrically large volume.

INI 2  
15:15 to 15:30 
Heterotic bundles on toric CalabiYau manifolds
We undertake a systematic scan of vector bundles over the database of torically generated CalabiYau threefolds in the context of heterotic string compactifications. Specifically, we construct positive monad bundles over CalabiYau hypersurfaces in toric varieties, with the number of Kahler moduli equal to one, two and three, and extract physically interesting models. We select models which can possibly lead to three families of matter after quotienting by a freelyacting discrete symmetries and including Wilson lines. About 2000 such models on two manifolds are found.

INI 1  
15:15 to 15:30 
Multifield inflationary trajectories with a fastturn feature
We study models of multifield inflation in which the inflationary trajectory contains a strong bending occurring when the observable scales are still inside the Hubble radius. We discuss the impact of such a fasttirn feature on the dynamics of the inflationary perturbations  and the traces such an event may leave in the power spectrum of curvature perturbations.

INI 2  
15:30 to 15:45 
Bundles over NearlyKahler Homogeneous Spaces in Heterotic String Theory with Flux
String compactifications incorporating nonvanishing Hflux have received increased attention over the past decade for their potential relevance to the moduli stabilization problem. Their internal spaces are in general not Kähler and, therefore, not CalabiYau. In the heterotic string an important technical problem is to construct gauge bundles on such spaces. I will present a method of how to explicitly construct gauge bundles over homogeneous nearlyKähler manifolds of dimension six. These bundles solve the heterotic string including first order alpha' corrections and allow for nonvanishing flux. I will also discuss some of the arising implications for model building.
Related Links •http://arxiv.org/abs/1107.3573  presented results are based on this paper 
INI 1  
15:30 to 15:45 
Lifshitz Solutions in String Theory
I will discuss solutions with Lifshitz scaling within string supergravity for an arbitrary scaling parameter z. After showing how to construct exact Lifshitz spacetimes, I will discuss more general solutions, including black holes with Lifshitz asymptotics.

INI 2  
15:45 to 16:15  Afternoon Tea  
16:15 to 16:30 
Fluxbrane Inflation
Fluxbrane inflation (arXiv:1104.5016) is a recently proposed stringy realisation of Dterm hybrid inflation, featuring some appealing phenomenological characteristics. In contrast to other brane inflation models, fluxbrane inflation has a naturally flat inflaton potential at leading order and thus does not rely on strong warping or an extremely anisotropic compact space. Additionally, the scenario contains a mechanism which allows one to avoid the clash with observational bounds due to cosmic string production rather easily. In my talk, I will present the most interesting aspects of the model and, furthermore, discuss recent progress and new challenges regarding moduli stabilisation (in the context of the LARGE volume scenario) as well as the impact of higherorder corrections on the flatness of the inflaton potential.

INI 1  
16:15 to 16:30 
On Asymptotically de Sitter Space: Entropy & Moduli Dynamics
I will discuss what the present state of the universe, as an asymptotically de Sitter space, tells us about the moduli dynamics in the very early universe. This study is inspired by entropy counting and holographic bounds.

INI 2  
16:30 to 16:45 
(New) Borders for Quantum Cosmology
Quantum Cosmology tackles the quantum description of the early universe. It is aimed as an accessible primer that covers the basics, critically discussing ideas and concepts that
comprise our current knowledge. The scope for analyzing quantum cosmological models within a supersymmetric framework is pointed.
As much as possible, it summarizes what we know, what we think we know and what we think we do not know on an equal footing. It is focused for ‘young’, inquisitive minds eager to embark on indepth research in this field. It is hoped to suggest the tools researchers will need to go on their own, pushing them to ask the right questions rather than seek definitive answers.

INI 1  
16:30 to 16:45 
SO(10) Resolutions in Ftheory
We discuss SO(10) GUTs in Ftheory, starting with the Tate form for a D5 singularity, and resolving. We then look at codimension two and three singularities to get matter and Yukawa couplings.

INI 2  
16:45 to 17:00 
Stringy Origins of Cosmic Structure: The Dbrane vector curvaton
I will discuss how the U(1) vector fields that live on the worldvolumes of Dbranes in Type IIB string theory may play the role of vector curvatons and hence give rise to distinctive features in the spectrum and bispectrum of the curvature perturbation. I will first consider vector fields on D3branes in openstring inflation, as a means of illustrating the principle. I will then discuss a D7brane vector curvaton scenario in closedstring inflation.

INI 1  
16:45 to 17:00 
M Kerstan (Universität Heidelberg) Fluxed M5instantons in Ftheory
We discuss the partition function of M5instantons in Ftheory, focussing in particular on vertical M5instantons that describe the uplift of Type IIB E3instantons. This duality allows us to determine the partition function of the M5instanton, which is nontrivial to obtain directly in Mtheory.

INI 2  
17:00 to 17:15  Break  
17:15 to 17:30 
Anomalies and Remnant Symmetries in Heterotic Constructions
First I discuss anomalies in heterotic compactifications. I argue that anomalies will generically not be universal, and illustrate this point by an explicit example of a heterotic orbifold blowup. Then, I investigate the origin of discrete (R and nonR) symmetries on smooth CalabiYau manifolds via an GLSM approach.

INI 1  
17:15 to 17:30 
P McGuirk (Cornell University) Hiddensector currentcurrent correlators in holographic gauge mediation
I will discuss gravity duals of the gauge mediation of supersymmetry breaking. In particular, I will discuss how the tools of AdS/CFT can be used to calculate certain twopoint functions in the hidden sector which, via the formalism of general gauge mediation, can be related to soft terms in the visible sector.

INI 2  
17:30 to 17:45 
Flux Quantization in Ftheory and FreedWitten Anomaly
Using M/Ftheory duality, I will relate the quantization of the Gflux in Mtheory to the one of the gauge flux on type IIB D7branes prescribed by FreedWitten anomaly cancellation. The correspondence is shown for all unitary and symplectic Kodaira singularities, by explicitly constructing appropriate 4cycles in the Mtheory elliptic fourfold, which are able to detect the global anomaly.

INI 1  
17:30 to 17:45 
OneLoop Calculation of the Oblique S Parameter in Higgsless Electroweak Models
If the Higgs boson does not show up soon, we should look for alternative mechanisms of mass generation, satisfying the many experimental constraints which the Standard Model (SM) has successfully fulfilled so far. Following this aim, we present a oneloop calculation of the oblique S parameter within Higgsless models of Electroweak Symmetry Breaking (EWSB) and analyze the phenomenological implications of the available electroweak precision data. By means of an effective Lagrangian we implement the chiral symmetry breaking SU(2)_L x SU(2)_R > SU(2)_(L+R) with Goldstones, gauge bosons and one multiplet of vector and axialvector massive resonance states. Using the dispersive representation of Peskin and Takeuchi and imposing the shortdistance constraints dictated by the operator product expansion, we obtain S at the nexttoleading order in terms of a few resonance parameters. We have found that, in order to match the experimental determination of the S parameter, the res onance masses are required to be over the TeV scale in this kind of stronglycoupled EWSB scenarios.

INI 2  
17:45 to 18:00 
Moduli Stabilisation of Heterotic String Theory with Flux
I will discuss the next to leading order corrections to the heterotic bundle constructions of Klaput, Lukas and Matti. I will show how these constructions lead to a nonzero Hflux at next to leading order, and how this flux may be used to stabilise either the dilaton, or the volume of the internal space. I will then add a gaugino condensate to the 4D supergravity, and show that for certain bundle choices it is possible to stabilise all moduli at consistent values.

INI 1  
17:45 to 18:00 
V Mehta (University of Liverpool) Stringderived models and light U(1) embeddings
Extra U(1) extensions of the Standard Model arising from string theory have been considered in the literature since the mid80s. Such a U(1) can play an important phenomenological role in solving the \mu problem and suppressing other unwanted operators, such as dimension four and five proton decay mediating operators. Yet keeping the U(1) unbroken down to low scales in quasirealistic string models turns out to be highly nontrivial. In this talk I will discuss the constraints and some scenarios in which they may be alleviated.

INI 2  
18:00 to 18:15 
D Mehta (Syracuse University) Numerical Algebraic Geometry: A New Perspective on String and Gauge Theories 
INI 1  
18:45 to 19:15  Dinner for Residents at Fitzwilliam & Churchill Colleges 
09:00 to 09:35  Searching for de Sitter vacua in String Theory  INI 1  
09:35 to 10:10 
Antibranes in KlebanovStrassler: to be or not to be?
Antibranes in the deformed conifold are used for example to construct de Sitter vacua. In the probe approximation, they lead to a metastable state. I will present work done over the last three years to go beyond the probe approximation by taking into account the backreaction of the antibranes. To be, or not to be (a metastable state), that is the question. We are pinning down the answer.

INI 1  
10:10 to 10:45 
The Wasteland of Random Supergravities
We show that in a general N=1 supergravity with N >> 1 scalar fields, an exponentially small fraction of the de Sitter critical points are metastable vacua. Taking the superpotential and Kahler potential to be random functions, we construct a random matrix model for the Hessian matrix, which is wellapproximated by the sum of a Wigner matrix and two Wishart matrices. We compute the eigenvalue spectrum analytically from the free convolution of the constituent spectra and find that in typical configurations, a significant fraction of the eigenvalues are negative. Using Coulomb gas techniques, we then determine the probability P of a large fluctuation in which all the eigenvalues become positive. Strong eigenvalue repulsion makes this extremely unlikely: we find P \propto exp(c N^2), with c a constant, for generic critical points. Our results have significant implications for the counting of de Sitter vacua in string theory, but the number of vacua remains vast.

INI 1  
10:45 to 11:20  Morning Coffee  
11:20 to 11:55 
Tensor modes on the string theory landscape
We attempt an estimate for the distribution of the tensor mode fraction $r$ over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards largefield or smallfield inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for smallfield vs largefield inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped CalabiYau flux compactifications of type IIB string theory.

INI 1  
11:55 to 12:30  String mass hierarchies and experimental predictions  INI 1  
12:30 to 13:30  Lunch at Wolfson Court  
14:00 to 14:35 
CalabiYau and NonCalabiYau backgrounds for heterotic phenomenology
I will discuss various aspects of model building and moduli stabilization in heterotic string theory. This will include building standard models from pure abelian gauge field configurations, and investigating compactifications on manifolds admitting SU(3) structures with intrinsic torsion.

INI 1  
14:35 to 15:10 
Vector Bundles and Moduli Stabilization in Heterotic Theories
I will discuss recent work on moduli stabilization without NeveuSchwarz threeform flux in CalabiYau compactifications of Heterotic Mtheory. In particular, I discuss a systematic approach to stabilizing the complex structure moduli in heterotic vacua and how the holomorphic deformations of the gauge bundle can naturally lead to the consideration of multiple CalabiYau threefolds, connected by geometric transitions.

INI 1  
15:10 to 15:45  Reflections on Ftheory Phenomenology  INI 1  
15:45 to 16:15  Afternoon Tea  
16:15 to 16:30 
Mixed WinoAxion Dark Matter in String/M Theory and the 130 GeV gammaline "Signal"
String/M theory compactifications with low energy supersymmetry tend to predict that dark matter has two components: axions and WIMPs \cite{1004.5138,1204.2795}. In accord with this, we show that the tentative 130 GeV gammaline signal reported in \cite{1204.2797} can be interpreted as arising from the annihilation of 145 GeV mass, Winolike WIMPs into a Zboson and a photon. In this context, the signal implies a second component of dark matter which we interpret as being composed of axions  the relative Wino/Axion abundances being approximately equal. Further predictions are implied: signals in both diffuse and monochromatic photons from dwarf spheroidal galaxies; monochromatic photons with energy 145 GeV; for the LHC, the Higgs boson mass has been predicted in this framework \cite{1112.1059}, and the current Higgs limits provide interesting constraints on the mass of the Gluino.

INI 1  
16:15 to 16:30 
The Conifold's Competing Condensates
We discuss holographic superconductivity in the context of IIB on AdS_5 x T^{1,1}. In the spectrum on the gravity side, there are several modes with potential instabilities. In addition to the one identifed by Gubser et al, we point out that there is another, potentially more unstable mode. Moreover, we propose a concrete model for the dynamics of this mode. With this proposal at hand, we show that it indeed dominates the thermodynamics at low temperatures.

INI 2  
16:30 to 16:45 
S Watson (Syracuse University) How UV sensitive is inflation?
We investigate the validity of effective field theory methods and the decoupling of heavy fields during inflation. Considering models of inflation in which the inflaton is coupled to heavy degrees of freedom, we find that violations of decoupling are absent unless there is a breakdown of the slowroll conditions. Next we allow for a temporary departure from inflation resulting in a period of nonadiabaticity during which effective field theory methods are known to fail. We find that the locality of the event and energy conservation lead to a tight bound on the size of the effects of the heavy field.

INI 1  
16:30 to 16:45 
Quasi Poisson structures, Courant algebroids and Bianchi identities for nongeometric fluxes
The notion of nongeometric flux was introduced in string theory to correctly describe the degrees of freedom in fourdimensional effective superpotentials of type II flux compactifications. Whereas the Hflux is simply the field strength of the NSNS Bfield and the fflux can be interpreted as the structure constants of a nonholonomic basis of the tangent bundle, the physical and mathematical properties of the remaining Q and Rfluxes are to a great extent unknown. In this talk, we will first use the notion of a (quasi)Poisson structure to rederive directly on the tangent bundle the commutation relations containing all four fluxes as structure constants. As a consequence, we get Bianchitype identities for the fluxes by writing down the Jacobiidentities for the algebra. Using these Bianchiidentities and the theory of quasi Liealgebroids, we are able to identify the associated Courant algebroid structure, which is essential for dealing with all fluxes being nonzero.

INI 2  
16:45 to 17:00 
Collider Phenomenology of String/M Theory
Very generic string/M theory assumptions can lead to nontrivial phenomenologies that can be tested at the LHC. The branching fraction to the 3rd family quarks of the gluino decay should be enhanced, leading to multilepton and/or multibjet signatures. On the other hand, chargino could have long enough lifetime to produce disappearing tracks in the detector.

INI 1  
16:45 to 17:00 
Moduli Dependence of M5instantons in Ftheory
M5instanton corrections to the superpotential in fourdimensional Ftheory compactifications have a modulidependent prefactor which contains interesting physical content. In two examples obtained via heterotic duality, I will show that the entire vanishing locus of the prefactor can be understood via simple Ftheory physics, often occurring at enhanced symmetry points in the complex structure moduli space. If time permits, I will discuss the relationship between line bundle cohomology on a distinguished curve in the instanton worldvolume and the intermediate Jacobian of the M5instanton.

INI 2  
17:00 to 17:15  Break  
17:15 to 17:30 
R Davies (University of Oxford) Dirac gauginos and unification in Ftheory
In the MSSM, the gauginos are assumed to acquire Majorana masses after supersymmetry breaking. If the light spectrum is extended slightly to include chiral multiplets in the adjoint representation of the gauge group, they can instead acquire Dirac masses by pairing up with the fermionic components of these multiplets. Dirac gauginos have several interesting properties, not least that they can be significantly heavier than Majorana gauginos, without paying any price in naturalness; this becomes particularly interesting in the light of the null results of the 2011 LHC searches for superpartners. One good reason for a theory to contain Dirac gauginos is if it has an unbroken (approximate) Rsymmetry. In string theory, the construction of models with adjoint chiral fields and (optionally) an unbroken Rsymmetry poses different problems to constructing the MSSM, especially as the gauge couplings no longer unify unless further matter is present. I will discuss solutions to some of these problems within the context of Ftheory.

INI 1  
17:15 to 17:30 
Systematic Investigations of the Heterotic String Landscape
Results are reviewed for the first stages of Baylor University’s ongoing systematic statistics investigations of the parameter space of free fermionic heterotic string models. Presented is the complete set of D = 4, 6 models with either maximal or completely broken spacetime SUSY that are constructed from the untwisted sector and exactly one additional gauge sector containing anywhere from order 2 through 32 twists. All additional models generated to date with additional twisted gauge sectors are also discussed. A vast degeneracy among models appears: from the roughly 2 billion D = 4 models with a single twist sector, only 577 physically distinct models appear. 68 of these have N = 4 SUSY and 509 have completely broken SUSY. To date, no new physically distinct models appear among any of those formed from two or more twisted gauge sectors. Several redundancies among D= 4 models and among D= 6 models are proven to result from redundancies already present among D= 10 models . Methods to reduce redundancies in D= 4, 6 systematic searches are summarized. Statistics regarding the appearance of various combinations of gauge group factors and of GUT groups among the set of 577 physically unique models are presented. Lastly, moving briefly to models with matter sectors, a model with an even number D of large spacetime dimensions is shown to always have maximal SUSY, if it is formed from the untwisted sector and a sector with a massless leftmover and an odd ordered rightmover.

INI 2  
17:30 to 17:45 
S Khalil (Zewail City of Science and Technology) TeV scale SUSY BL
We propose a scheme where the three relevant physics scales related to the supersymmetry, electroweak, and baryon minus lepton (BL) breakings are linked together and occur at the TeV scale. The phenomenological implications in the Higgs and leptonic sectors are discussed.

INI 1  
17:30 to 17:45 
B Jurke (Northeastern University) Scanning for Swiss Cheese geometries
Moduli stabilization in the Large Volume Scenario requires a specific kind of sixdimensional CalabiYau geometry for the compactification procedure, which is being referred to as "Swiss Cheese" due to the presence of certain holes for instanton wrappings. Only a handful of such manifolds are known explicitly. I will give an overview of the Large Volume Scenario and present recent progress on a general scan of the CalabiYau threefold landscape for the Swiss Cheese property.

INI 2  
17:45 to 18:00 
padic Strings at Finite Temperature
We study the finite temperature theory of padic string models. We analyze the partition function and main thermodynamic properties arising from perturbative thermal loops. We find that the thermal properties of these nonlocal field theories can be interpreted either as contributions of standard thermal modes with energies proportional to the temperature, or inverse thermal modes with energies proportional to the inverse of the temperature, leading to a thermal duality at leading order analogous to the well known Tduality of string theory.

INI 1  
17:45 to 18:00 
B Heidenreich (Cornell University) Orientifolds and new N=1 Dualities
I report on a new class of N=1 dualities relating different gauge theories arising from D3 branes probing orientifold singularities. These dualities provide new, nontrivial solutions to the 't Hooft anomaly matching conditions. I discuss an infinite class of orbifold singularities where the duality can be interpreted as Sduality in ten dimensions. I also discuss nonorbifold singularities, and the microscopic interpretation of the duality in terms of an orientifold transition between compact O7+ and O7 planes.

INI 2  
18:45 to 19:15  Dinner for Residents at Fitzwilliam & Churchill Colleges 
09:00 to 09:35 
Type II and Ftheory Instanton Effects
We address Dinstanton contributions to the nonperturbative superpotential in Type II and Ftheory, employing multipronged approaches, including heterotic and Mtheory dualities. We focus focus on the determination of instanton zero modes and their contributions to the superpotential Pfaffian structure.

INI 1  
09:35 to 10:10 
Fluxes and Warping in Ftheory
We discuss the effective theory of Ftheory compactifications by using the Mtheory dual. Two main results are highlighted: (1) the chiral index of a 4D Ftheory compactification can be determined by fourform flux when comparing 3D ChernSimons theories at one loop, (2) the inclusion of warping effects due to fluxes in Mtheory is crucial to determine corrections to the Ftheory effective theory even if in the latter warping effects can be neglected.

INI 1  
10:10 to 10:45  Dark Matter density and the Higgs mass in LVS String Phenomenology.  INI 1  
10:45 to 11:20  Morning Coffee  
11:20 to 11:55 
F Marchesano (IFTUAM/CSIC) Yukawas in FTheory 
INI 1  
11:55 to 12:30 
Wavefunctions and local models in Ftheory
I will discuss general aspects of wavefunctions and their overlaps in local Ftheory models with an aim towards developing the ideas of ultra local model building.

INI 1  
12:30 to 13:30  Lunch at Wolfson Court  
14:00 to 14:35 
S SchaferNameki (King's College London) Ftheory and Gflux 
INI 1  
14:35 to 15:10 
T Weigand (Universität Heidelberg) Gauge fluxes and M5instantons in Ftheory and their Type IIB duals
I discuss recent progress in the description of G4 gauge fluxes in Ftheory compactifications on CalabiYau fourfolds. Such fluxes are important from the perspective of Ftheory model building, where gauge fluxes are required for example for the generation of chiral matter. An explicit dictionary between a class of factorisable G4 fluxes in certain Ftheory compactifications and corresponding diagonal U(1) fluxes in Type IIB orientifolds sheds new light on the uplift of Type IIB vacua to Ftheory. This global description of gauge fluxes in Ftheory also allows for the evaluation of selection rules for M5instantons to contribute to the superpotential.

INI 1  
15:10 to 15:45 
Nonabelian discrete gauge symmetries in string theory
I will discuss the realization of nonabelian discrete gauge symmetries in field theory and string theory, and present several classes of string models exhibiting nonabelian discrete gauge symmetries. In models of magnetized/intersecting Dbranes, the discrete symmetries impose nontrivial constraints on Yukawa couplings, and correspond to interesting flavour symmetries in MSSMlike models.

INI 1  
15:45 to 16:15  Afternoon Tea  
16:15 to 16:30 
S Groot Nibbelink (LudwigMaximiliansUniversität München) Super Weyl invariance: BPS equations from heterotic worldsheets
It is wellknown that the beta functions on a string worldsheet correspond to the target space equations of motion, e.g. the Einstein equations. We show that the BPS equations, i.e. the conditions of vanishing supersymmetry variations of the spacetime fermions, can be directly derived from the worldsheet. To this end we consider a heterotic worldsheet model in the RNSformulation with (2,0) supersymmetry, which describes a complex torsion target space that supports a holomorphic vector bundle. After a detailed account of its quantization and renormalization, we establish that super Weyl anomaly cancellation implies the heterotic BPS conditions: At the one loop level the geometry is required to be conformally balanced and the gauge background has to satisfy the Hermitean YangMills equations.

INI 1  
16:15 to 16:30 
Towards the Standard Model on Rigid DBranes
Dbrane worlds have provided a geometrically intuitive approach for Standard Model (SM) engineering within string theory compactifications. While the types and ranks of gauge groups and the chiral matter content are tackled in a straightforward manner, it remains on the one hand an open question if the SM can be obtained on rigid Dbranes  without continuous gauge symmetry breaking along flat directions and with nontrivial Dbrane instanton contributions to the effective action  and on the other hand if such models are consistent with lowenergy data. The T6/Z(2)xZ(6') orbifold with discrete torsion admits a plethora of leftright symmetric `local models' without exotic matter in the adjoint, symmetric or antisymmetric representation. However, `global' completions usually come at the cost of introducing new exotic states in bifundamental representations. It furthermore turns out that USp(2) and SO(2) in place of U(2) symmetries can at most provide one particle generation. Last but not least, it turns out that for any T6/Z(2)xZ(2M) orbifold with discrete torsion and tilted tori, orientifold invariant stacks of D6branes carry USp(2N) or SO(2N) gauge groups depending on their relative position to the exotic O6plane. The new classification reduces the number of Ktheory constraints. If time permits, I will briefly comment on the drastic change in the pattern of Yukawa couplings on orbifolds compared to the sixtorus using a T6/Z6' example. As a result, quark Yukawas can provide large mixings while lepton Yukawas are flavour diagonal at leading order. Also the rule of `one massive generation only' is circumvented.

INI 2  
16:30 to 16:45 
GLSM descriptions of heterotic compactification spaces
Gauged Linear Sigma Models (GLSMs) provide a framework for studying different phases of compactification spaces for heterotic string theories. Among them are toroidal orbifolds and smooth CalabiYau constructions, both of which are very popular among string model builders. Up to now, quite a few MSSMlike string models have been constructed based on these compactification spaces. We describe the construction of toroidal orbifolds and describe how to obtain their smooth CalabiYau counterparts in the GLSM framework. The two regimes lie at different regions in Kahler moduli space, which can be accessed by tuning the FayetIliopoulos GLSM parameters. However, upon probing the entire moduli space, also other phases are encountered which do not have a geometric interpretation as straightforward as the previously mentioned ones. Furthermore, there can be flop and floplike transitions which further subdivide the different phases.

INI 1  
16:30 to 16:45 
Superpotential desequestering as a source of flavour violation
Nonperturbative effects such as gaugino condensation on a stack of D7branes are an essential ingredient in several celebrated modulistabilisation schemes in type IIB string theory. At the level of the fourdimensional effective theory, the nonperturbative effects induce a nonperturbative superpotential. In particular, new Yukawa interactions can be generated. Type IIB orbifold models contain the essential features to study these nonperturbative corrections to the superpotential in string compactifications. I will describe under which conditions new Yukawa couplings arise in these settings and generalise the results to more realistic string models. Most importantly, I will show that the flavour structure of the induced Yukawa couplings is not aligned with the treelevel flavour structure, thus introducing a new source of flavor violation.

INI 2  
16:45 to 17:00 
S Parameswaran (Leibniz Universität Hannover) Coupling Selection Rules in Heterotic Orbifold Compactifications
Heterotic orbifolds provide a simple, globally consistent framework in which one can obtain the MSSM particle spectrum with no chiral exotics from string theory. In order to understand the dynamical aspects and phenomenology of these compactifications, such as the decoupling of vectorlike exotics, moduli stabilization, particle masses and couplings, we must compute the couplings in the corresponding low energy effective field theory.
We study Lpoint string correlation functions and thus derive string selection rules, which determine the allowed couplings in the superpotential of the low energy effective supergravity theory.

INI 1  
16:45 to 17:00 
The Coulomb Gas of Random Supergravities
I will discuss the mass spectrum of fourdimensional {\cal N}=1 supergravity in which the Kähler potential and superpotential are taken to be random functions of N chiral superfields. For both supersymmetric and nonsupersymmetric critical points, the ensemble of Hessian matrices can be efficiently studied through the ‘Coulomb gas’ formulation of Random Matrix Theory. At large N, the supersymmetric AdS vacua have a very peculiar spectrum which typically includes many BFallowed tachyons, and I will briefly discuss the prospects of obtaining metastable de Sitter vacua from an ‘uplift’ of a supersymmetric AdS vacuum. An exponentially small fraction de Sitter critical points with spontaneously broken supersymmetry are metastable vacua, and I will discuss how the Coulomb gas formulation can be used to find the joint probability distribution of the masses, the fraction of critical points which are vacua, and the spectrum of the vacua. I will conclude by b riefly discussing some cosmological consequences of these results.

INI 2  
17:00 to 17:15  Break  
17:15 to 17:30 
U(n) Spectral Covers from Decomposition
We construct decomposed spectral covers for bundles on elliptically fibered CalabiYau threefolds whose structure groups are S(U(1) x U(4)), S(U(2) x U(3)) and S(U(1) x U(1) x U(3)) in heterotic string compactifications. The decomposition requires not only the tuning of the SU(5) spectral covers but also the tuning of the complex structure moduli of the CalabiYau threefolds. This configuration is translated to geometric data on Ftheory side. We find that the monodromy locus for twocycles in K3 fibered CalabiYau fourfolds in a stable degeneration limit is globally factorized with squared factors under the decomposition conditions. This signals that the monodromy group is reduced and there is a U(1) symmetry in a low energy effective field theory. To support that, we explicitly check the reduction of a monodromy group in a slice of the moduli space for an E6 gauge theory with (1+2) decomposition. This may provide a systematic way for constructing some Ftheory models with U (1) symmetries.

INI 1  
17:15 to 17:30 
Exceptional Flux Compactifications
In the last decade, a framework in which string dualities are implemented at the supergravity level has been developed, i.e., the socalled embedding tensor formalism. However, the connection between this formalism and string theory realisations remains still obscure since most of the supergravities obtained by using the embedding tensor formalism correspond to very exotic (non)geometries in the string side.
In this talk we consider type II flux backgrounds compatible with the absence of brane sources, and construct their explicit embedding into maximal D=4 supergravity. This enables us to investigate the critical points, mass spectra and gauge groups of such "exceptional" backgrounds in a systematic way. We will chart the landscape of vacua in some specific setups which are relevant from the string theory viewpoint and discuss the issues of stability and supersymmetry at those vacuum solutions. Finally we will point towards some natural extensions of the results.

INI 2  
17:30 to 17:45 
C Mayrhofer (Universität Heidelberg) Searching for Phenomenologically Attractive CalabiYaus with Kähler Classes Variant under Orientifolding
We give a detailed account of our search for CalabiYau threefolds with two toric del Pezzo divisors of the same kind and an orientifold involution which maps them into each other. We will consider hypersurface CalabiYaus in toric fourfolds with $h^{1,1}$ up to five and comment on the relevance of these geometries in string phenomenology.

INI 1  
17:30 to 17:45 
A Borghese (Rijksuniversiteit Groningen) A geometric bound for Fterm inflation
There has been a lot of efforts during the last decade in order to provide a supergravity realisation of inflation. This is of crucial importance if one look at supergravity as the bridge connecting the effective field theory of inflation and a possible UV complete theory like string theory. Within a supergravity theory the inflationary dynamics is tightly constrained. I will discuss a particular kind of geometric constraints which arise by considering particular directions on the scalar manifold, namely the ones which are singled out by the process of supersymmetry breaking (the so called sGoldstino’s). As an example I will consider the constraint in the case of N=1, Fterm inflation.

INI 2  
17:45 to 18:00  Model building and moduli stabilisation in CalabiYau orientifold compactifications with branes at singularities  INI 1  
17:45 to 18:00 
On the Beaming of Gluonic Fields at Strong Coupling
We examine the conditions for beaming of the gluonic field sourced by a heavy quark in stronglycoupled conformal field theories, using the AdS/CFT correspondence. Previous works have found that, contrary to naive expectations, it is possible to set up collimated beams of gluonic radiation despite the strong coupling. We show that, on the gravity side of the correspondence, this follows directly (for arbitrary quark motion, and independently of any approximations) from the fact that the string dual to the quark remains unexpectedly close to the AdS boundary whenever the quark moves ultrarelativistically. We also work out the validity conditions for a related approximation scheme that proposed to explain the beaming effect though the formation of shock waves in the bulk fields emitted by the string. We find that these conditions are fulfilled in the case of ultrarelativistic uniform circular motion that motivated the proposal, but unfortunately do not hold for much more gen eral quark trajectories.

INI 2  
19:30 to 22:00  Conference Dinner at Christ's College 
09:00 to 09:35 
L Ibanez ([Universidad Autonoma de Madrid and IFTUAM/CSIC]) The SUSY breaking scale and Ftheory unification 
INI 1  
09:35 to 10:10 
AN Schellekens (National Institute for Subatomic Physics (Nikhef)) Discrete gauge symmetries in discrete orientifolds
We study the origin of discrete gauge symmetries from open string sector U(1)'s in orientifolds based on rational conformal field theory. By means of an explicit construction, we find an integral basis for the couplings of axions and U(1) factors for all simple current MIPFs and orientifolds of all 168 Gepner models, a total of 32990 distinct cases. We discuss how the presence of discrete symmetries surviving as a subgroup of broken U(1)'s can be derived using this basis. We apply this procedure to models with MSSM chiral spectrum, concretely to all known U(3)xU(2)xU(1)xU(1) and U(3)xSp(2)xU(1)xU(1) configurations with chiral bifundamentals, but no chiral tensors, as well as some SU(5) GUT models.

INI 1  
10:10 to 10:45  The Dark OPERA  INI 1  
10:45 to 11:20  Morning Coffee  
11:20 to 11:55 
Phenomenological Heterotic Theory: Standard Models, the Renormalization Group and All That
A class of hidden sector polystable vector bundles will be presented that, when used in combination with SU(4) heterotic standard model bundles, lead to completely stable string vacua with exactly the particle spectrum of the MSSM with three righthanded neutrino supermultiplets. Threshold corrections, the effective Lagrangian with soft supersymmetry breaking and its scaling under the renormalization group are discussed. It is shown that gauged BL symmetry and electroweak symmetry are radiatively broken with a small hierarchy over a wide range of initial parameters. Implications of these SU(4) heterotic standard models for the LHC are explored.

INI 1  
11:55 to 12:30 
Heterotic Line Bundle Models in Four Dimensions
We introduce heterotic line bundle standard models and, more generally, heterotic split models focusing on their fourdimensional effective supergravity theories. The general structure of these theories and a number of phenomenological issues, including fermion masses, proton decay and moduli stabilization will be discussed.

INI 1  
12:30 to 12:35  Announcement of String Pheno 2013  INI 1  
12:35 to 13:30  Lunch at Wolfson Court  
14:00 to 14:35 
G Dall'agata (Università degli Studi di Padova) New facts on classical and quantum N=8 supergravity
N=8 supergravity is currently at the center of many investigations because of its possible ultraviolet finiteness. I will present some new results on its spontaneously broken version. I will prove that all models with N=0 Minkowski vacua are finite at 1loop. I will also discuss a new mechanism to study the classical vacua, show that there are many more deformations than previously expected and that from a stringy perspective broken N=8 supergravity exhibits a moduli space with some intriguing features.

INI 1  
14:35 to 15:10 
I GarciaEtxebarria (CERN  European Organisation for Nuclear Research) New N=1 dualities from contracting orientifolds
I will describe recent work on a new class of dualities, directly inherited from IIB Sduality, in 4d theories with 4 supercharges.
I will focus on the microscopic description of the duality, when realized in terms of system of branes at singularities in string theory. The theories in question are obtained by considering, in addition to the fractional branes, orientifold planes wrapping vanishing 4cycles.
I will discuss the system from the point of view of large volume branes, focusing in particular on the relevant issues when continuing orientifolds of quiver gauge theories to large volume. This discussion provides a first principles derivation of the relevant orientifolded quivers. By studying the strongly coupled behavior of the resulting orientifold+brane configuration, I will argue for the existance of a dual, weakly coupled description of the strongly coupled quiver theory at the singularity.

INI 1  
15:10 to 15:45  Closing Comments  INI 1  
15:45 to 16:20  Afternoon Tea  
18:45 to 19:15  Dinner for Residents at Fitzwilliam & Churchill Colleges 