54th Schladming Winter School of Theoretical Physics

21 Feb 2016, 08:00 → 26 Feb 2016, 20:00 Europe/Zurich

Schladming, Austria

Registration is closed

The focus of the 2016 edition of the Schladming Winter School in Theoretical Physics will be on new trends and open challenges in the understanding of the microcosm. With the discovery of a Standard Model-like scalar boson at the LHC and no further clear-cut observation of new phenomena at the electroweak scale the quest for a natural description of the microcosm has become even more pressing.

Evaluating new theoretical frameworks which UV-complete the Standard Model or benchmark models beyond the Standard Model, fascinates physicists across the various communities including those working on model building, particle phenomenology, quantum gravity, cosmology and formal theory.

Several key speakers will address this topic from different angles:

• Astrid Eichhorn (Imperial College London): Asymptotic Safety

• Petr Horava (Berkeley Center for Theoretical Physics, University of California, San Francisco): Gravity and the Quantum

• Hugh Osborn (DAMTP, University of Cambridge) : Formal Advances in Quantum Field Theory

• Veronica Sanz (University of Sussex): Models for the LHC and Beyond

• Martin Schmaltz (Boston University): Towards a Fundamental Theory Beyond the Standard Model

• Mikhail Shaposhnikov (École Polytechnique Fédérale de Lausanne): Particle Physics and Cosmology

• Christof Wetterich (University of Heidelberg): Fixed Points in Quantum Gravity and Cosmology

Financial support by the City of Schladming, the Province of Styria, the University of Graz and the ERC Advanced Grant: Functional Renormalization in Quantum Field Theory and Statistical Physics (ERC-AdG-290623 ) is gratefully acknowledged.

The lectures by Prof. Tilman Plehn (University of Heidelberg) had to be canceled on short notice. We are thankful to Prof. Veronica Sanz (University of Sussex) that she will cover many topics originally planned to be covered by the lectures of Prof. Plehn.

Final Circular.pdf

Poster_Schladming2016.pdf

SeminarSchedule.pdf

Timetable_2016.pdf

Sunday, 21 February

08:45 → 09:45 Registration

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Osborn

10:00 Advances in Quantum Field Theory. Lecture I

Osborn_Lecture1.pdf

11:00 → 12:00 Lecture: Eichhorn

11:00 Asymptotic Safety. Lecture I

Schladming_2016_Astrid_Eichhorn_lecture1.pdf

16:45 → 17:45 Lecture: Horava

16:45 Gravity and the Quantum. Lecture I

sch1.pdf

19:00 → 22:00 Opening Ceremony

Monday, 22 February

08:45 → 09:45 Lecture: Osborn

08:45 Advances in Quantum Field Theory. Lecture II

Osborn_2+3.pdf

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Horava

10:00 Gravity and the Quantum. Lecture II

sch2.pdf

11:00 → 12:00 Lecture: Sanz

11:00 Models for the LHC and Beyond. Lecture I

Schladming_Sanz.pdf

16:45 → 17:45 Contributed talks: Sondenheimer / Loose / Christiansen

Sondenheimer
Mati
Christiansen

16:45 Sondenheimer -- Nonperturbative RG flow of the Higgs potential

We reanalyze the conventional arguments that relate a lower bound for the Higgs mass with vacuum stability in the framework of the functional renormalization group as well as in the light of exact results for the regularized fermion determinant. In both cases, we find no indication for vacuum instability nor metastability induced by top fluctuations if the cutoff is kept finite but arbitrary for standard bare actions which are perturbatively renormalizable. We show that a finite infrared Higgs mass range emerges naturally from the renormalization group flow itself. Higgs masses outside the resulting bounds cannot be connected to any conceivable set of bare parameters within the class of quartic bare potentials. However, the lower bound can be relaxed considerably by more general forms of the bare potential without necessarily introducing new metastable minima.

Speaker: Mr René Sondenheimer (FSU Jena)

Sondenheimer-Schladming2016.pdf

17:05 Loose

Experimental findings in semileptonic B decays by LHCb, Belle and BaBar hint at a possible violation of lepton universality. We investigate an explanation of this anomaly within leptoquark scenarios and point out correlations which arise from flavor symmetries that are known to be capable of describing the observed mixing of quarks and leptons.

Speaker: Mr Dennis Loose (TU Dortmund)

Loose.pdf

17:25 Christiansen -- Local Quantum Gravity

I investigate the ultraviolet behaviour of quantum gravity within a functional renormalization group approach. In particular, the scale- and momentum-dependence of the graviton propagator and the graviton three-point function are studied and the fixed point structure of the theory is analyzed. Moreover, a novel locality property as an essential feature of a well-defined renormalization group flow is intrdouced and locality in quantum gravity is discussed.

Speaker: Dr Nicolai Christiansen (Institute for Theoretical Physics, Heidelberg University)

Christiansen_Schladming_2016.pdf

17:45 → 18:00 Coffee

18:00 → 19:00 Lecture: Sanz

18:00 Models for the LHC and Beyond. Lecture II

19:00 → 20:00 Contributed talks: Schnabl / Kitamura / Karateev

Sondenheimer
Mati
Christiansen

19:00 Schnabl

I will review the subject of topological defects in 2d CFT and discuss the novel aspects which arise in presence of boundaries. I will mention applications to open string field theory.

Speaker: Dr Martin Schnabl (Institute of Physics AS CR)

19:20 Kitamura -- Tree-level Unitarity and Renormalizability in Lifshitz Scalar Theory

I studied the equivalence between tree unitarity and renormalizability in Lifshitz scalar theory. Tree-level unitarity and renormalizability are believed to be equivalent in field theories. No counter-example is known in relativistic field theories. However, the question whether the equivalence holds true for more generic field theories, such as non-relativistic theories is obscure. In my study, I discussed the equivalence between tree-level unitarity and renormalizability and showed that the equivalence holds true in Lifshitz (non-relativistic) scalar field theory. It can be inferred that tree-level unitarity is useful to investigate renormalizability in a large class field theories, such as Horava-Lifshitz gravity.

Speaker: Mr Tomotaka Kitamura (Waseda University)

Winter School_Kitamura.pdf

19:40 Karateev -- Some Recent Developments in 4D CFTs

In this short talk I will briefly summarise non-perturbative non-lagrangian formulation of CFTs and the philosophy of conformal bootstrap. I will then focus on 4D CFTs and discuss 3- and 4- point functions of operators with arbitrary spin: their computation, importance and future applications for conformal bootstrap.

Speaker: Mr Denis Karateev (SISSA)

Karateev.pdf

Tuesday, 23 February

08:45 → 09:45 Lecture: Horava

08:45 Gravity and the Quantum. Lecture III

sch3.pdf

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Eichhorn

10:00 Asymptotic Safety. Lecture II

Schladming_2016_Astrid_Eichhorn_lecture2.pdf

11:00 → 12:00 Lecture: Sanz

11:00 Models for the LHC and Beyond. Lecture III

16:45 → 17:45 Contributed talks: Gold / Huber / Mitter

Sondenheimer
Mati
Christiansen

16:45 Gold -- Probing astrophysical black holes with gravitational waves and light

Speaker: Dr Roman Gold (University of Maryland)

gold.odp

17:05 Huber -- A non-perturbative study of the correlation functions of three-dimensional Yang-Mills theory

Functional equations like the functional renormalization group, Dyson-Schwinger equations or n-PI methods are useful tools which provide insight into the non-perturbative regime of quantum field theories. The basic objects are Green functions which can be calculated non-perturbatively. However, while the underlying equations are exact, approximations have to be introduced for the actual calculations. I will discuss the effects of such approximations in the case of three-dimensional Yang-Mills theory. This theory is UV finite. As a consequence, some technical ambiguities of the four-dimensional theory are absent which can cloud the effects of truncations.

Speaker: Dr Markus Huber (University of Graz)

Huber.pdf

17:25 Mitter -- Yang-Mills correlation functions from the functional renormalization group

We investigate SU(3)-Yang-Mills theory in a systematic vertex expansion scheme for the effective action. Particular focus is put on the dynamical creation of the gluon mass gap at non-perturbative momenta and the consistent treatment of quadratic divergences. The gluon and ghost propagators as well as the momentum-dependent ghost-gluon, three-gluon and four-gluon vertices are calculated self-consistently and the apparent convergence of the expansion scheme is discussed by comparing to corresponding lattice QCD results.

Speaker: Dr Mario Mitter (University of Heidelberg)

Mitter_Schladming16.pdf

17:45 → 18:00 Coffee

18:00 → 19:00 Contributed talks: Hiller / Bond / Maas

Sondenheimer
Mati
Christiansen

18:00 Hiller -- BSM Flavor Physics with Charm, Beauty and Leptons

Flavor physics is highly sensitive to beyond the standard model (BSM) physics and vice versa. In this talk we demonstrate this explicitly in the example of bottom-up leptoquark extensions of the Standard Model. Recent anomalies in rare B-meson decays into leptons hinting at lepton non-unversality are addressed. The talk is based on recent works arxiv:1408.1627, 1503.01084 and 1510.00311, all hep-ph.

Speaker: Prof. Gudrun Hiller (TU Dortmund)

Schladming2016-ghiller.pdf

18:20 Bond -- Renormalisation group flow of perturbative field theories

Renormalisation group flow of perturbative field theories

Speaker: Mr Andrew Bond (University of Sussex)

Schladming2016-AndrewBond.pdf

18:40 Maas -- Physical spectra and new physics

Experimentally observable particles require a gauge-invariant description. In non-Abelian gauge theories this implies that only composite operators, and thus bound states, can be physical. Though bound states are genuine non-perturbative objects, the Froehlich-Morcchio-Strocchi mechanism nonetheless provides a possibility to determine the masses of Higgs, W, and Z using perturbation theory. After describing this mechanism, and its ramifications for the standard model, the situation for new physics models will be discussed. The implications for the 2-Higgs doublet models, grand-unified theories, and technicolor will be presented. Special attention will be paid to the question where a breakdown of this mechanism could occur.

Speaker: Prof. Axel Maas (University of Graz)

Maas.pdf

19:15 → 21:00 Poster Session

19:15 Poster Presenters

Natalia Alkofer -- Spectral Dimensions from the Spectral Action -- Reinhard Alkofer: The Rotating Mass Shell: A counter-example to Mach's principle? -- Adrian Lorenz Blum -- Symmetry-broken phase of $\phi^{4}$-theory from the FRG Julia Borchardt -- Global flow of the Higgs potential in a Yukawa model Tugba Buyukbese -- Anton Konrad Cyrol -- Yang-Mills correlation functions from functional methods Christian Ecker -- Guman Garayev -- Aaron Held -- Sergei Iurev -- Ju-Hyun Jung -- The pion-dressing effect of Nucleon and Delta Wolfgang Lucha -- Janus-facedness of the pion: analytic instantaneous Bethe-Salpeter models Wout Merbis -- Christoph Niehoff -- Tetiana Obikhod -- Sebastian Ohmer -- Hande Özçelik -- Jordi París López -- SU(3)-Symmetric Sum Rules For B->PP Decays Colin Poole -- Peter Posfay -- Manuel Reichert -- Chris Ripken: Curvature on the noncommutative tangent bundle -- Christian Rohrhofer -- Angular momentum content of the $\rho(1450)$ from chiral lattice fermions Wolfgang Schweiger -- Andrey Shkerin -- Tom Steudtner -- Resummation of Logarithmic Enhanced Contributions to the Higgs Mass in FlexibleSUSY Pascal Törek -- Partially Higgsed Gauge Theory Masatoshi Yamada -- Electroweak and Dark matter scalegenesis from a bilinear scalar condensate Felix Ziegler

Wednesday, 24 February

08:45 → 09:45 Lecture: Sanz

08:45 Models for the LHC and Beyond. Lecture IV

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Schmaltz

10:00 Fundamental Theory Beyond the SM. Lecture I

Schmaltz_1.pdf

11:00 → 12:00 Lecture: Horava

11:00 Gravity and the Quantum. Lecture IV

sch4.pdf

14:30 → 16:00 Ski Race

17:45 → 18:00 Coffee

18:00 → 19:00 Lecture: Shaposhnikov

18:00 Particle Physics and Cosmology. Lecture I

schaldmingL1_2016.pdf

19:00 → 20:00 Contributed talks: Mati / Fumagalli / Ramírez Rodríguez

Sondenheimer
Mati
Christiansen

19:00 Mati -- Critical scaling in the large-N O(N) model in higher dimensions and its possible connection to quantum gravity

The critical scaling of the large-N O(N) model in higher dimensions using the exact renormalization group equations has been studied, motivated by the recently found non-trivial fixed point in 4<d<6 dimensions with metastable critical potential. Particular attention is paid to the case of d=5 where the scaling exponent of the correlation length has the value 1/3, which coincides with the scaling exponent of quantum gravity in one fewer dimensions. Convincing results show that this relation could be generalized to arbitrary number of dimensions above five. Some aspects of AdS/CFT correspondence are also discussed.

Speaker: Dr Peter Mati (ELI-ALPS)

schladming16_Mati.pdf

19:20 Fumagalli -- Predictiveness of inflation with the Higgs boson

The predictions of (Standard model) Higgs inflation are in excellent agreement with the Planck data, without needing new particles beyond the ones we know. Nevertheless, introducing some threshold corrections is demanded by the consistency of the theory. This raises the question: how sensitive the CMB predictions are to the UV completion? I will show that as long as the UV corrections do not affect the inflaton potential at tree level but only enter at loop level via corrections to the renormalization group equations, the inflationary predictions are (almost) unaffected.

Speaker: Mr Jacopo Fumagalli (NIKHEF)

JFumagalli_Schladming2016.pdf

19:40 Ramírez Rodríguez -- Do current data prefer a nonminimally coupled inflaton?

Inflation provides the most theoretically attractive and observationally successful cosmological scenario able to generate the initial conditions of our universe. From the theoretical viewpoint, this picture is usually understood as the dynamics of a single new scalar degree of freedom, the inflaton, minimally coupled to gravity. However, generally the inflaton is expected to have a nonminimal coupling to the Ricci scalar. While the minimally-coupled version of the chaotic model of inflation is ruled out at more than 99% confidence level (for 50 e-folds of inflation), in this talk we will see that the presence of such coupling, for the chaotic model, is highly favoured with respect to the latest analysis of Planck and BICEP2.

Speaker: Mr Héctor Ramírez Rodríguez (IFIC - University of Valencia)

Héctor Ramírez.pdf

20:15 → 22:00 Victory Ceremony

Thursday, 25 February

08:45 → 09:45 Lecture: Eichhorn

08:45 Asymptotic Safety. Lecture III

Schladming_2016_Astrid_Eichhorn_lecture3.pdf

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Sanz

10:00 Models for the LHC and Beyond. Lecture V

11:00 → 12:00 Lecture: Osborn

11:00 Advances in Quantum Field Theory. Lecture III

16:45 → 17:45 Lecture: Shaposhnikov

16:45 Particle Physics and Cosmology. Lecture II

schaldmingL2_2016.pdf

17:45 → 18:00 Coffee

18:00 → 19:00 Lecture: Schmaltz

18:00 Fundamental Theory Beyond the SM. Lecture II

Schmaltz_2.pdf

20:00 → 21:00 Public Lecture Wetterich

20:00 Raum , Zeit, Universum - die Rätsel des „Beginns“

Friday, 26 February

08:45 → 09:45 Lecture: Eichhorn

08:45 Asymptotic Safety. Lecture IV

Schladming_2016_lecture4_Astrid_Eichhorn.pdf

09:45 → 10:00 Coffee

10:00 → 11:00 Lecture: Osborn

10:00 Advances in Quantum Field Theory. Lecture IV

Osborn_Lecture4.pdf

11:00 → 12:00 Lecture: Schmaltz

11:00 Fundamental Theory Beyond the SM. Lecture III

Schmaltz_3.pdf

16:45 → 17:45 Lecture: Shaposhnikov

16:45 Particle Physics and Cosmology. Lecture III

schaldmingL3_2016.pdf

17:45 → 18:00 Coffee

18:00 → 19:00 Lecture: Wetterich

18:00 Fixed points in quantum gravity and cosmology

Wetterich_Scale_Symmetry_Cosmology.pdf

Wetterich_Scale_Symmetry_Cosmology.ppt

19:00 → 20:00 Closing