Topical Workshop: Rethinking Naturalness

Contribution List

4. Classical scale invariance, Physical Naturalness and the stability of scales

MARTTI RAIDAL

12/17/14, 10:00 AM

The discovery of Higgs boson, apparent absence of any new physics at EW scale and the existence of perturbative physics at and above Planck scale, as hinted by BICEP2, require rethinking the paradigm of naturalness. I suggest that no explicit mass terms exist in fundamental Lagrangian (the concept of classical scale invariance) and all scales are generated via logarithmic dimensional...

0. SUSY “naturalness” and LHC-14

Alberto Casas

12/17/14, 11:30 AM

The idea of "Natural SUSY", understood as a supersymmetric scenario where the fine-tuning is as mild as possible, is a reasonable guide to explore supersymmetric phenomenology. I will discuss the probabilistic meaning of conventional fine-tuning measures and re-examine the MSSM naturalness bounds including several improvements; e.g. the role played by potential extra fine-tunings, which must...

7. Theoretical implications of present LHC unobservation

ALESSANDRO STRUMIA

12/17/14, 3:00 PM

The experimental results of the first run of the Large Hadron Collider lead to the discovery of the Higgs boson but have not confirmed the dominant theoretical paradigm about the naturalness of the electro-weak scale, according to which the Higgs boson should have been accompanied by supersymmetric particles or by some other new physics able of protecting the Higgs boson mass from...

3. Conformal and Electro-Weak Symmetry Breaking

MANFRED LINDNER

12/18/14, 10:00 AM

I will discuss possible connections between the breaking of conformal and electro-weak symmetry. Models realizing this ideas and phenomenological implications as well as open questions will be covered as well.

1. Criteria for Natural Hierarchies

ANDRÉ DE GOUVÊA

12/18/14, 11:30 AM

I revisit the issue of naturalness, discussing some of the implicit assumptions that underly most of the discussions on this topic. I discuss a more pragmatic definition of the hierarchy problem that does not rely on peeking beyond the murky boundaries of quantum field theory and investigate the fine-tuning of the electroweak scale associated with thresholds from heavy particles, which...

2. Electroweak Vacuum Stability after LHC8

JOSE RAMON ESPINOSA

12/18/14, 3:00 PM

The discovery of the Higgs boson by the LHC in 2012, and especially the determination of its mass around 125 GeV, together with the absence of any trace of new physics, make it conceivable that we live in a metastable electroweak vacuum. This vacuum turns out to be extremely long-lived as that particular mass value means we live quite close to the stability boundary. I will describe the...

6. Quantum scale invariance and naturalness

Mikhail Shaposhnikov

12/19/14, 10:00 AM

I will discuss quantum scale invariant effective theories of particle physics and gravity and their relevance to the hierarchy problem.

5. Composite versus Elementary Higgs: Problems and Progress

FRANCESCO SANNINO

12/19/14, 11:30 AM

I will critically introduce, classify and discuss the fundamental open issues related to either composite or elementary Higgs extensions of the standard model. As for the progress I will exhibit, among other things, our first proof of existence of nonsupersymmetric Gauge-Yukawa theories (structurally identical to the standard model) which are UV finite thanks to the existence of an exact...

8. Dark matter and the multiverse: WIMPs and axions

DUCCIO PAPPADOPULO (California U., Berkeley)

12/19/14, 3:00 PM

The observed values of the cosmological constant and the abundance of dark matter can be understood, using certain measures, by imposing the anthropic requirement that density perturbations go non-linear and virialize to form haloes. This requires a probability distribution favoring low amounts of dark matter, i.e. low value of the axion scale f for the QCD axion and low values of the...