Minimality versus naturalness: How many new particles do we need?
by
CYCL01
Marc de Hemptinne (chemin du Cyclotron, 2, Louvain-la-Neuve)
Program:
16:15 IRMP Colloquium talk at CYCL01
17:30 Drinks and snacks with the speaker in the Cyclofette
About the speaker:
Mikhail Shaposhnikov has made numerous contributions to theoretical particle physics and cosmology that shaped these fields. Most notably, he has contributed to the foundations of electroweak baryogenesis and leptogenesis, was amongst the first to propose brane worlds, made important contributions to thermal field theory, and first pointed out that the Higgs boson could drive cosmic inflation. More recently, he has contributed to CERN's experimental program as one of the original proposers of the SHiP experiment and by highlighting the FCC-ee's potential to discover long-lived particles.
Summary:
Nature contains several seemingly independent mass scales. The smallest of them is associated with the accelerated expansion of the Universe which can be explained by the vacuum energy $(\epsilon_V)^{\frac{1}{4}}\sim 2.26\times 10^{-3}$ eV. The next one is the QCD confinement scale, establishing the typical size of hadrons, $\Lambda_{QCD} \sim 100$ MeV. The Fermi scale is related to the mass of the weak intermediate vector bosons, $M_W \sim 100$ GeV. The largest scale is associated with the strength of the gravitational interactions given by the Planck mass $M_P\sim 10^{19}$ GeV. I will discuss whether the multitude of these scales scattered by many orders of magnitude implies the existence of new particles and forces yet to be discovered and deliberate on the question formulated in the title.