Marcos Marino
(Geneva)
24/09/2013, 14:10
Gerald Dunne
(Connecticut)
24/09/2013, 14:50
"Resurgent" semiclassical analysis, a systematic unification of perturbative and non-perturbative sectors, can be applied to resolve fundamental problems in quantum theories with degenerate minima. Expansions about different saddle points are quantitatively related to one another in a precise manner. Illustrations include double-well and periodic potentials in QM, and asymptotically free QFTs...
Antonio Gonzalez-Arroyo
(UAM/CSIC)
24/09/2013, 15:30
Zohar Komargodski
(Weizmann Institute of Science)
25/09/2013, 09:10
Shlomo Razamat
(Princeton University)
25/09/2013, 10:30
Prof.
Aalok Misra
(Indian Institute of Technology Roorkee)
25/09/2013, 14:00
Particle Phenomenology
We present a phenomenological model which could possibly be obtained as a local Swiss-Cheese Calabi-Yau string-theoretic compactification in the large volume limit with a mobile D3-brane restricted to a nearly special Lagrangian cycle in the Calabi-Yau and fluxed stacks of wrapped D7-branes. The model provides a natural realization of mu-Split SUSY with a high SUSY-breaking scale wherein the...
Christoph Mayrhofer
(Heidelberg University)
25/09/2013, 14:00
Strings & Mathematical Physics
In this talk we will describe the construction of F-Theory GUT models for elliptically fibred Calabi-Yau fourfolds admitting a non-trivial Mordell-Weil group. We work out the matter spectrum and Yukawa couplings, including singlets, for these geometries and present the fluxes corresponding to the U(1) symmetries.
Mr
Rafael Alves Batista
(II. Institute for Theoretical Physics, University of Hamburg)
25/09/2013, 14:20
Cosmology & Astroparticle Physics
The origin, chemical composition, and mechanisms of acceleration of the ultra-high energy cosmic rays (UHECRs) are not yet well understood. Aiming for a better interpretation of the available experimental data, these data have to be confronted with theoretical models. In this sense, the development of numerical tools to propagate UHECRs is essential to constrain astrophysical parameters....
Dr
Noppadol Mekareeya
(Max Planck Institute for Physics)
25/09/2013, 14:30
Strings & Mathematical Physics
In this talk, I will present a method for a systematic study of the moduli spaces of Yang-Mills instantons in a simple gauge group. For a classical group, the moduli space can be studied via the ADHM construction, which can be realised from the Lagrangian of a certain quiver gauge theory with 8 supercharges. Such a construction is, however, not available for instantons in exceptional gauge...
Dr
Giorgio Arcadi
(University of Göttingen)
25/09/2013, 14:40
Particle Phenomenology
Decaying Dark Matter is an interesting and viable alternative to the common paradigm of stable Dark Matter. We consider a simple extension of the Standard model with two states, a Dark Matter Majorana fermion and a colored or only electroweakly charged scalar, without introducing any symmetry to stabilize the DM state. We identify the parameter region accounting for an Indirect Dark Matter...
Mr
Jie Gu
(Universität Bonn)
25/09/2013, 15:00
Strings & Mathematical Physics
It's been conjectured that the Chern-Simons theory with SU(N) group on S3 in the large N limit can be described by closed topological string. When a Wilson line operator along some knot is inserted in the Chern-Simons theory, some brane appears in the topological string. We give support to the second half of the conjecture by computing the instanton numbers in B-model, using the topological...
Andrey Saveliev
(University of Hamburg)
25/09/2013, 15:00
Cosmology & Astroparticle Physics
We present our results from semi-analytic computations on the time evolution of the energy content for primordial magnetic fields and the accompanying turbulent flows in the general framework of an expanding Universe with homogeneous and isotropic turbulence. In particular we include the backreaction of the turbulent medium on the magnetic field and point out the effect of helicity compared to...
Mr
Martin Sprenger
(DESY)
25/09/2013, 15:50
Strings & Mathematical Physics
In this talk, I will present results for the 6- and 7-point amplitude in strongly coupled N=4 super Yang-Mills theory in the multi-Regge regime. I will review the calculation of scattering amplitudes in strongly coupled N=4 SYM, where calculating the amplitude corresponds to calculating a specific minimal surface embedded into AdS5.
The leading order solution of this problem is determined...
Dr
Marc Gillioz
(CP3-Origins, University of Southern Denmark)
25/09/2013, 15:50
Particle Phenomenology
The conformal symmetry plays an important role in quantum field theories, even when it is explicitly broken by a renormalization group flow. The Weyl consistency conditions reflect its presence in the renormalized theory. They provide relations among the beta functions of the theory at different loop orders. As an example, we show how the Weyl consistency conditions affect the computation of...
Prof.
Jacek Wosiek
(Jagellonian University)
25/09/2013, 16:10
Particle Phenomenology
After explaining the role of generalized, i.e. multi-parton, ‘t Hooft equations in QCD, their numeric and analytic solutions will be discussed. The intriguing localization property, together with stringy interpretation will be demonstrated. Finally, we will derive analytically the complete basis of localized solutions satisfying appropriate, infrared safe, boundary conditions in all parton...
Dr
Ben Hoare
(Humboldt-Universität zu Berlin)
25/09/2013, 16:10
Strings & Mathematical Physics
In this talk we will discuss recent developments in the application of unitarity techniques to 2-d integrable field theories. After outlining the general construction (mainly focussing on one loop, but with some comments on two), we will apply the method to various integrable theories, finding evidence that the one-loop S-matrix is cut-constructible. The final part of the talk will focus on...
Prof.
Andrew Koshelkin
(Moscow Institute for Physics and Engineering)
25/09/2013, 16:30
Particle Phenomenology
In order to describe the dynamics of particle production and hadron spectrum in a flux tube, we start with an action integral in QCD4 in (3+1)dimensional space-time with a confining scalar transverse
interaction. Under the dominance of longitudinal motion of the
valence quark-antiquark pair, the four dimensional space-time
QCD4 can be compactified into QCD2 in (1+1)...
Mr
Tobias Hansen
(Universitaet Hamburg)
25/09/2013, 16:30
Strings & Mathematical Physics
Tree level unitarity relates the residues of N-point amplitudes of scalars to lower point amplitudes of all particles in the spectrum of a theory. I will explain in the case of open bosonic string theory how to exploit this relation, in which one has to sum over all particles that are on-shell at the residue in question and all its possible polarizations. In contrast to Yang-Mills theory, here...
Mr
Ilmar Gahramanov
(Humboldt-University Berlin)
25/09/2013, 16:50
Strings & Mathematical Physics
By reduction of a single letter index a natural connection is found between superconformal indices of even-dimensional supersymmetric theories. We find that the superconformal index of the 4d N=2, 4 theory reduces to the superconformal index of the N=(2,2), (4,4) theory in the certain limit of the superconformal fugacities. The proposed reduction procedure could also help to extract...
Dr
Pedro Schwaller
(CERN)
25/09/2013, 16:50
Particle Phenomenology
Most of the mass of ordinary matter has its origin from quantum chromodynamics (QCD). A similar strong dynamics, dark QCD, could exist to explain the mass origin of dark matter. Using infrared fixed points of the two gauge couplings, we provide a dynamical mechanism that relates the dark QCD confinement scale to our QCD scale, and hence provides an explanation for comparable dark baryon and...
Dr
Marco Drewes
(TU München)
25/09/2013, 17:10
Cosmology & Astroparticle Physics
I discuss leptogenesis in the type I seesaw model with Majorana masses below the electroweak scale and the perspectives to test this scenario in the laboratory. It is often stated that it can only be realised if either two Majorana masses are highly degenerate or new degrees of freedom in addition to the right handed neutrinos are added to the Standard Model. This is, however, only true in...
Daniele Dorigoni
(DAMPT Cambridge)
25/09/2013, 17:10
Strings & Mathematical Physics
Also in theories without instantons non-perturbative saddle points play a crucial role. Using the example of the 2d principal chiral model we show how resurgence theory, which unifies perturbative and non-perturbative physics, predicts the existence of several types of non-perturbative saddles: the fractons. With these new saddles is possible to understand the quantum interpretation of...
Markus Luty
(UC Davis)
26/09/2013, 09:00
Nadav Drukker
(King's College London)
26/09/2013, 09:40
Riccardo Rattazzi
(EPFL Lausanne)
26/09/2013, 10:20
Alberto Ramos
(DESY)
26/09/2013, 11:30
Kari Rummukainen
(Helsinki)
26/09/2013, 12:10
Dr
Luca Zambelli
(TPI, Friedrich-Schiller-Universität Jena)
26/09/2013, 14:00
Particle Phenomenology
We investigate chiral Higgs-Yukawa models with a non-abelian gauged left-handed sector reminiscent to a sub-sector of the standard model. We discover a new weak-coupling fixed-point behavior that allows for ultraviolet complete RG trajectories which can be connected with a conventional long-range infrared behavior in the Higgs phase. Despite the weak coupling properties, the system exhibits...
Valerie Domcke
(DESY)
26/09/2013, 14:00
Cosmology & Astroparticle Physics
A remarkable feature of the recently published Planck data is that one of the oldest models of inflation, the R^2 inflation model proposed by Starobinsky, fits the data strikingly well. In this talk, I show how the Starobinsky model arises asymptotically in the large field limit of a supergravity D-term hybrid inflation model based on an approximate superconformal symmetry. This ...
Martin Ammon
(Friedrich-Schiller University Jena)
26/09/2013, 14:00
Strings & Mathematical Physics
Holographic entanglement entropy provides a direct connection between classical geometry and quantum entanglement; however the usual prescription does not apply to theories of higher spin gravity, where standard notions of geometry are no longer gauge invariant. We present a proposal for the holographic computation of entanglement entropy in field theories dual to higher spin theories of...
Dr
Anosh Joseph
(DESY Zeuthen)
26/09/2013, 14:20
Particle Phenomenology
We construct lattice action for three-dimensional N=4 supersymmetric gauge theory with matter fields in the fundamental representation. We also discuss the construction of N=4 U(N_1)xU(N_2) quiver lattice gauge theory with bi-fundamental matter fields. Some issues such as flat directions, fine tuning and sign problem appearing in these theories are also briefly discussed.
Dr
Aleksey Cherman
(FTPI, University of Minnesota)
26/09/2013, 14:30
Strings & Mathematical Physics
Large-N volume independence in circle-compactified QCD with Nf ≥ 1 adjoint Weyl fermions implies the absence of any phase transitions as the radius is dialed to arbitrarily small values. This class of theories are believed to possess a Hagedorn density of hadronic states. These properties are in apparent tension with each other, because a Hagedorn density of states typically implies a phase...
Mr
Clemens Wieck
(DESY Hamburg)
26/09/2013, 14:30
Cosmology & Astroparticle Physics
We study the effects of coupling hybrid inflation to moduli stabilization as employed in certain type IIB string compactifications with D-branes and fluxes. In a scenario with a single Kahler modulus stabilized in a racetrack potential, F-term hybrid inflation is unfeasible due to either a large inflaton mass or a tachyonic direction. However, we present a working model of D-term hybrid...
Mr
Christian Weiss
(Institute for theoretical particle physics and cosmlogy, RWTH Aachen University)
26/09/2013, 14:40
Particle Phenomenology
Precision calculations for hadron colliders require numerous computational methods, among others the simulation of parton showers. They provide a good description of collinear radiation, i.e. the internal structure of jets. However, to better describe the production of jets, NLO matrix elements are needed. Their interface to parton showers involves problem, leading to the loss of NLO accuracy....
Dr
Oliver Schlotterer
(AEI Potsdam)
26/09/2013, 15:00
Strings & Mathematical Physics
We discuss tree level scattering of massless open superstring states on a worldsheet of disk topology -- for any number of external legs. The entire state dependence of these disk amplitudes can be expressed in terms of gauge theory subamplitudes from the point particle limit. The string corrections entering through momentum dependent integrals over the disk boundary can be disentangled from...
Thomas Flacke
(Korea Advanced Institute of Science and Technology (KAIST))
26/09/2013, 15:00
Particle Phenomenology
Composite Higgs models represent an attractive extension of the Standard Model of particle physics, providing a solution to the hierarchy problem. The Higgs-like particle is realized as a bound state of a strongly coupled sector. This implies the existence of further bound states at the TeV scale, which can be searched for at the LHC. In this talk we focus on the composite quark partners, i.e....
Mr
Mirco Wörmann
(Universität Bielefeld)
26/09/2013, 15:00
Cosmology & Astroparticle Physics
Dr
Anthony Hartin
(DESY)
26/09/2013, 15:50
Particle Phenomenology
A non-perturbative QFT - the Furry picture - which treats the interaction of particles with each other perturbatively and with intense electromagnetic fields exactly, is already used routinely in the calculation of the beamstrahlung and coherent pair production. The current implementation of the theory for existing calculations requires the approximation of ultra-relativistic, co-linear...
Mr
Maximilian Poretschkin
(Bethe Center for Theoretical Physics)
26/09/2013, 15:50
Strings & Mathematical Physics
The most detailed information about rigid $\mathcal{N}=2$ supersymmetric theories in $\mathbb{R}^4 \times S^1$ is contained in a supersymmetric index counting refined BPS states. They fall into representations of SU(2)$_L$ $\times$ SU(2)$_R$, the little group in 5$d$, which has an induced action on the cohomology of the moduli space of stable pairs.
I will present the computation of...
Dr
Masaki Asano
(University of Hamburg)
26/09/2013, 16:10
Particle Phenomenology
Natural supersymmetric spectra require light Higgsinos, light stops and sbottom to achieve the correct electroweak symmetry breaking without a fine tuning. Furthermore, taking into account two loop contribution to the Higgs mass squared term, gluino would not be very heavy. We study the gluino decay signal in natural supersymmetric spectra at the LHC. It would be different from simplified...
Mr
Daniel Plencner
(LMU Munich)
26/09/2013, 16:10
Strings & Mathematical Physics
Orbifolding a 2-dimensional quantum field theory by a symmetry group admits an elegant description in terms of defect lines and their junction fields. This perspective offers a natural generalization of the concept of an orbifold, in which the role of the symmetry group is replaced by a defect with the structure of a (symmetric) separable Frobenius algebra. In this talk I will focus on the...
Mr
Václav Tlapák
(DESY)
26/09/2013, 16:30
Strings & Mathematical Physics
Replacing the regular Lie groups in the coset construction of Goddard-Kent-Olive (GKO) with Lie supergroups yields conformal but non-unitary 2-dimensional QFTs. We extend previous studies of exactly marginal deformations in such superspace coset models to hermitian symmetric superspaces. In this case we obtain several families of N=2 superconformal field theories with continuously varying exponents.
Germano Nardini
(Universität Bielefeld)
26/09/2013, 16:30
Cosmology & Astroparticle Physics
In order to explain the observed baryon asymmetry of the Universe, electroweak baryogenesis requires that the electroweak symmetry breaking occurred via a strong first-order phase transition. As proven more than a decade ago for a (lighter CP-even) Higgs mass m_h <~ 100 GeV, such a condition is fulfilled in the MSSM if the right-handed stop is very light. Recently, the same conclusion was...
Dr
Rose Lerner
(Helsinki University)
26/09/2013, 16:50
Cosmology & Astroparticle Physics
The curvaton is only a spectator field during inflation, but produces the observed curvature perturbation when it decays after inflation. We present a simple "realistic" model for the curvaton mechanism, where the curvaton is a real scalar coupled to the standard model Higgs Boson. This coupling to the higgs results both in interesting stochastic behaviour of the field during inflation, and in...
Dr
Cagnazzo Alessandra
(DESY)
26/09/2013, 16:50
Strings & Mathematical Physics
The study of Superstring Theories on AdS backgrounds is important in the context of Gauge/Gravity correspondence. These theories can be reduced, under certain assumptions, to Sigma Models on semi-symmetric super-cosets. For a peculiar class of these cosets one can also introduce a WZ term. This correspond to study a Superstring Theory on a background supported by a mixture of RR and NSNS...
Dr
Kohei Kamada
(DESY)
26/09/2013, 17:10
Cosmology & Astroparticle Physics
Recent LHC results suggest the electroweak vacuum metastability. Although its lifetime is longer than the cosmic age in almost all the parameter space, quantum tunneling to the unwanted true vacuum in the quasi-de Sitter background may occur during inflation. This, in turn, constrains severely high-scale inflation models. In this talk, we discuss how to avoid such tunneling during high-scale...
Mr
Federico Bonetti
(MPI Munich)
26/09/2013, 17:10
Strings & Mathematical Physics
A five-dimensional approach to six-dimensional tensor theories is discussed, which makes use of towers of massive five-dimensional tensors in a Kaluza-Klein inspired fashion. The relation to Chern-Simons theories in five dimensions is considered at the quantum level. A five-dimensional supersymmetric Lagrangian with tensor towers is proposed to furnish a description of non-Abelian (2,0) theories.
Dr
Christoph Horst
(University of Hamburg)
26/09/2013, 17:30
Strings & Mathematical Physics
We study N=2 vacua in gauged N=4 supergravity theories in four-dimensional spacetime. Using the embedding tensor formalism that describes general consistent magnetic gaugings of an ungauged N=4 matter-coupled supergravity theory in a symplectic frame with SO(1,1) x SO(6,n) off-shell symmetry we formulate necessary conditions for partial supersymmetry breaking and find that the Killing spinor...
Ioannis Florakis
(MPI Physik)
26/09/2013, 17:50
I will present a new class of N=2 amplitudes in string theory, generalizing the well-known F-terms which compute the topological string theory partition function. These generalized F-terms involve, in addition to the standard anti-self-dual graviphoton background, additional insertions of self-dual vertices. The latter can be identified, using the non-trivial constraint that the correct N = 2...
Gregory Korchemsky
(IPhT Saclay)
27/09/2013, 09:30
Daniel Jafferis
(Harvard)
27/09/2013, 10:10
Benjamin Basso
(PI Waterloo)
27/09/2013, 11:20
Mikhail Shifman
(UM Minneapolis)
27/09/2013, 12:00
Ioannis Florakis
(MPI Physik)
Strings & Mathematical Physics
I will present a new class of N=2 amplitudes in string theory, generalizing the well-known F-terms which compute the topological string theory partition function. These generalized F-terms involve, in addition to the standard anti-self-dual graviphoton background, additional insertions of self-dual vertices. The latter can be identified, using the non-trivial constraint that the correct N = 2...
