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The asymptotic safety paradigm is currently emerging as a highly promising idea for Beyond-Standard-Model physics, with key progress in asymptotically safe quantum gravity and asymptotically safe matter models. The last years have seen not only the development of asymptotically safe gravity-matter models, but also the discovery of asymptotically safe beyond Standard Model matter models that are under control in perturbation theory. New exciting avenues in (astro) particle physics are now waiting to be explored.
For example, although the nature of dark matter is a long-standing riddle it is a fact that experimental searches have so far not provided any direct clues, but have instead come up with ever more stringent constraints on theoretically preferred regions of parameter space for dark-matter-models. Thus, the key to unraveling this riddle could be a new theoretical paradigm to guide model builders.
This workshop aims at exploring whether asymptotic safety can be a candidate for this new paradigm. We aim to bring together experts on phenomenological models and quantum gravity to probe both the theoretical viability and empirical signatures of asymptotically safe extensions of the standard model that include gravity.
To facilitate a highly productive meeting that can trigger new collaborations, each talk will be followed up by 15-20 minutes discussion time. Further, each day of the workshop will feature a dedicated discussion session. Participants will be encouraged to contribute questions for the discussion both before as well as during the workshop. The last day of the workshop will conclude with a roadmap discussion, during which all participants will be given the opportunity to propose concrete suggestions for follow-up work that might lead into future joint projects.
Sponsorship for this conference has been provided by:
- Steven Abel, Durham University
- Niayesh Afshordi, Perimeter Institute & University of Waterloo
- Nicola Dondi, CP3 Origins
- Astrid Eichhorn, Heidelberg University
- Daniel Litim, University of Sussex
- Robert Mann, Perimeter Institute & University of Waterloo
- Manuel Reichert, Heidelberg University
- Alberto Salvio, CERN
- Francesco Sannino, CP3 Origins
- Anders Eller Thomsen, CP3 Origins
- Masatoshi Yamada, Heidelberg University
- Zhi-Wei Wang, University of Waterloo
- Steven Abel, Durham University
- Niayesh Afshordi, Perimeter Institute & University of Waterloo
- Kaca Bradonjic, Hampshire College
- Robert Brandenberger, McGill University
- Nicola Dondi, CP3 Origins
- Astrid Eichhorn, Heidelberg University
- Daniel Litim, University of Sussex
- Robert Mann, Perimeter Institute & University of Waterloo
- Manuel Reichert, Heidelberg University
- Alberto Salvio, CERN
- Francesco Sannino, CP3 Origins
- Barak Shoshany, Perimeter Institute
- Tom Steele, University of Saskatchewan
- Anders Eller Thomsen, CP3 Origins
- Masatoshi Yamada, Heidelberg University
- Zhi-Wei Wang, University of Waterloo
Tuesday, June 5, 2018
Time |
Event |
Location |
8:30 – 9:00am |
Registration |
Reception |
9:00 – 9:15am |
Welcome &Opening Remarks |
Bob Room |
9:15 – 10:00am |
Francesco Sannino, CP3 Origins |
Bob Room |
10:00 – 10:45am |
Daniel Litim, University of Sussex |
Bob Room |
10:45 – 11:15am |
Coffee Break |
Bistro – 1^{st} Floor |
11:15 – 12:00pm |
Discussion 1 |
Bob Room |
12:00 – 2:30pm |
Lunch |
Bistro – 1^{st} Floor |
2:30 - 3:15pm |
Steven Abel, Durham University |
Bob Room |
3:15-3:45pm |
Coffee Break |
Bob Room |
3:45 – 4:30pm |
Niayesh Afshordi, Perimeter Institute & University of Waterloo |
Bob Room |
4:30 – 5:00pm |
Discussion 2 |
Bob Room |
5:00 – 6:00pm |
Wine & Cheese Reception |
Bistro – 2^{nd} Floor |
Wednesday, June 6, 2018
Time |
Event |
Location |
9:15 – 10:00am |
Alberto Salvio, CERN |
Bob Room |
10:00 – 10:45am |
Manuel Reichert, Heidelberg University |
Bob Room |
10:45 – 11:15am |
Coffee Break |
Bistro – 1^{st} Floor |
11:15 – 12:00pm |
Astrid Eichhorn, Heidelberg University |
Bob Room |
12:00 – 2:30pm |
Lunch |
Bistro – 1^{st} Floor |
2:30 - 3:15pm |
Anders Eller Thomsen, CP3 Origins |
Bob Room |
3:15-3:45pm |
Coffee Break |
Bob Room |
3:45 – 4:30pm |
Nicola Dondi, CP3 Origins |
Bob Room |
4:30 – 5:00pm |
Discussion 3 |
Bob Room |
Thursday, June 7, 2018
Time |
Event |
Location |
9:15 – 10:00am |
Robert Mann, Perimeter Institute & University of Waterloo |
Bob Room |
10:00 – 10:45am |
Zhi-Wei Wang, University of Waterloo |
Bob Room |
10:45 – 11:15am |
Coffee Break |
Bistro – 1^{st} Floor |
11:15 – 12:00pm |
Discussion 4 |
Bob Room |
12:00 – 2:30pm |
Lunch |
Bistro – 1^{st} Floor |
2:30 - 3:15pm |
Masatoshi Yamanda, Heidelberg University |
Bob Room |
3:15-3:45pm |
Coffee Break |
Bob Room |
3:45 – 4:30pm |
Roadmap Discussion |
Bob Room |
Steven Abel, Durham University
Progress in constructing an Asymptotically safe Standard Model
I outline a configuration in which the Standard Model can be embedded into an asymptotically safe gauge-Yukawa theory. The model can be though of as a minimal UV completion of the SM without gravity. I also discuss the remaining issues that need to be addressed for the scheme to be phenomenologically viable, and outline the different energy scales and possible signatures.
http://kacabradonjic.com/projections/#jp-carousel-1563
http://kacabradonjic.com/projections/#jp-carousel-1564
Niayesh Afshordi, Perimeter Institute & University of Waterloo
Cosmological non-Constant Problem
I will discuss how studying the gravitational effects of UV physics on large (astrophysical) scales precludes new mass scales in BSM physics beyond 600 GeV.
http://kacabradonjic.com/projections/#jp-carousel-1553
Nicola Dondi, CP3 Origins
Constraining Asymptotic Safety using central charges
I will present constraints from central charges and gradient flow relations on UV and IR interacting fixed points under perturbative control. It is possible to extend this methodology beyond perturbation theory for supersymmetric theories where the central charges are calculated to all orders. In this case, these constraints draw a complex map of possible RG flows, some of them compatible with Asymptotic Safety. Examples of such SUSY theories are discussed.
http://kacabradonjic.com/projections/#jp-carousel-1561
Astrid Eichhorn, Heidelberg University
Shedding light on dark matter in asymptotic safety
The nature of dark matter is one of the outstanding riddles of fundamental physics. Here, I will discuss first steps to explore dark matter in the asymptotic safety paradigm. As a first example, I will show indications for an asymptotically safe fixed point in the Higgs portal to fermionic dark matter, leading to a relation between the Higgs portal coupling and the dark matter mass. This model also serves as an example for different mechanisms that generate asymptotic safety.
I will then review some properties of an extended Higgs sector under the coupling to asymptotically safe quantum gravity and discuss how quantum gravity fluctuations flatten the Higgs potential and thus lead to a decoupling of scalar singlets which are subject to experimental searches for dark matter.
http://kacabradonjic.com/projections/#jp-carousel-1555
Daniel Litim, University of Sussex
Asymptotic safety with and without supersymmetry
I discuss the state of affairs for asymptotic safety in particle physics with and without supersymmetry.
http://kacabradonjic.com/projections/#jp-carousel-1556
Robert Mann, Perimeter Institute & University of Waterloo
Keeping the Standard Model Safe
An increasing number of researchers are considering the possibility that the Standard Model, appropriately extended, can attain an interacting ultraviolet fixed point. Such a theory could, in the Wilsonian sense, be regarded as a fundamental theory. I will describe recent work that shows this goal is attainable in principle by adding gauged vector-like fermions to the Standard Model, in the limit of a large number of fermion fields. With this proof-of-principle demonstration, the challenge now to find realistic asymptotically safe extensions of the Standard Model with interesting and falsifiable phenomenological signatures
http://kacabradonjic.com/projections/#jp-carousel-1562
Manuel Reichert, Heidelberg University
Asymptotic safety of gravity-matter systems and effective universality
We review the status of asymptotically safe gravity-matter systems. The existence of a UV fixed point in such systems is guaranteed if the matter-self couplings are weak and if higher-derivative gravity terms are neglected. We show how this can manifest itself in a functional renormalisation group computation. Such gravity-matter systems contain various avatars of the dynamical Newton's coupling, e.g. gravitational self-couplings or matter-graviton couplings. We uncover an effective universality for the dynamical Newton's coupling on the quantum level: its momentum-dependent avatars are in remarkable quantitative agreement in the scaling regime of the UV fixed point. This emergence of effective universality is a strong indication for the physical nature of the UV fixed point and it provides a guiding principle for setting up future truncations.
http://kacabradonjic.com/projections/#jp-carousel-1559
Alberto Salvio, CERN
UV-complete relativistic field theories and softened gravity
A field theory is fundamental if it features a UV fixed point (either trivial or interacting). Gravity may not change drastically the UV behavior if the Einstein gravitational interactions are softened above a critical sub-Planckian energy scale. A concrete implementation of this softened gravity can be obtained by adding terms quadratic in the curvature to the Einstein-Hilbert action. One way to implement this scenario consists in requiring that all matter couplings flow to zero at infinite energy (total asymptotic freedom). More generally, some of the couplings flow to zero, while others approach interacting fixed points. The requirement of having a fundamental field theory can have important implications for particle physics phenomenology.
Francesco Sannino, CP3 Origins
Charting Fundamental Interactions
I summarise the state-of-the-art in our understanding of fundamental interactions and will set the stage for present and future studies and phenomenological applications.
http://kacabradonjic.com/projections/#jp-carousel-1557
http://kacabradonjic.com/projections/#jp-carousel-1558
Anders Eller Thomsen, CP3 Origins
Beta functions at large N_f
Including a large number of vector-like fermions can be used to generate fixed points for the RG flows of gauge theories. Recently this has been used as a foundation for constructing UV safe models. The talk will focus on the machinery behind the large N_f computations extended to generic gauge-Yukawa theories. For semi-simple gauge theories the phase diagram shows the persistence that the UV fixed point of simple gauge theories.
http://kacabradonjic.com/projections/#jp-carousel-1554
Zhi-Wei Wang, University of Waterloo
Asymptotically Safe Grand Unified Theories
http://kacabradonjic.com/projections/#jp-carousel-1565
Masatoshi Yamanda, Heidelberg University
Asymptotically safe gravity and electroweak scalegenesis
We discuss the impact of quantum gravity fluctuations on a scalar mass. In case that the scalar mass becomes irrelevant above the Planck scale, there could be solutions to the gauge hierarchy problem. In this talk, we consider the so-called classically scale invariant extension of the standard model, where non-abelian scalar-gauge theory in a dark sector is introduced to explain the origin of the electroweak scale. We discuss its phenomenological implications towards probing new physics.
http://kacabradonjic.com/projections/#jp-carousel-1560
Discussion Session 1
http://kacabradonjic.com/projections/#jp-carousel-1567
Discussion Session 2
http://kacabradonjic.com/projections/#jp-carousel-1568
All paintings courtesy of Kaća Bradonjić
Roadmap Discussion
Asymptotically safe gravity and electroweak scalegenesis
We discuss the impact of quantum gravity fluctuations on a scalar mass. In case that the scalar mass becomes irrelevant above the Planck scale, there could be solutions to the gauge hierarchy problem. In this talk, we consider the so-called classically scale invariant extension of the standard model, where non-abelian scalar-gauge theory in a dark sector is introduced to explain the origin of the electroweak scale. We discuss its phenomenological implications towards probing new physics.
Discussion 4
Asymptotically Safe Grand Unified Theories
Keeping the Standard Model Safe
An increasing number of researchers are considering the possibility that the Standard Model, appropriately extended, can attain an interacting ultraviolet fixed point. Such a theory could, in the Wilsonian sense, be regarded as a fundamental theory. I will describe recent work that shows this goal is attainable in principle by adding gauged vector-like fermions to the Standard Model, in the limit of a large number of fermion fields.
Discussion 3
Constraining Asymptotic Safety using central charges
I will present constraints from central charges and gradient flow relations on UV and IR interacting fixed points under perturbative control. It is possible to extend this methodology beyond perturbation theory for supersymmetric theories where the central charges are calculated to all orders. In this case, these constraints draw a complex map of possible RG flows, some of them compatible with Asymptotic Safety. Examples of such SUSY theories are discussed
Beta functions at large N_f
Including a large number of vector-like fermions can be used to generate fixed points for the RG flows of gauge theories. Recently this has been used as a foundation for constructing UV safe models. The talk will focus on the machinery behind the large N_f computations extended to generic gauge-Yukawa theories. For semi-simple gauge theories the phase diagram shows the persistence that the UV fixed point of simple gauge theories.
Shedding light on dark matter in asymptotic safety
The nature of dark matter is one of the outstanding riddles of fundamental physics. Here, I will discuss first steps to explore dark matter in the asymptotic safety paradigm. As a first example, I will show indications for an asymptotically safe fixed point in the Higgs portal to fermionic dark matter, leading to a relation between the Higgs portal coupling and the dark matter mass. This model also serves as an example for different mechanisms that generate asymptotic safety.
Asymptotic safety of gravity-matter systems and effective universality
We review the status of asymptotically safe gravity-matter systems. The existence of a UV fixed point in such systems is guaranteed if the matter-self couplings are weak and if higher-derivative gravity terms are neglected. We show how this can manifest itself in a functional renormalisation group computation. Such gravity-matter systems contain various avatars of the dynamical Newton's coupling, e.g. gravitational self-couplings or matter-graviton couplings.
Pages
Scientific Organizers:
- Niayesh Afshordi, Perimeter Institute & University of Waterloo
- Astrid Eichhorn, Heidelberg University
- Robert Mann, Perimeter Institute & University of Waterloo