HIP NEWS November 11th 2013
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DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS
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Tuesday 12 November 2013 at 10.15 in A315
Antonio Racioppi (NICPB, Tallinn)
Towards Completing the Standard Model
Abstract: We study the standard model (SM) in its full perturbative validity range between LambdaQCD and the U(1)_Y Landau pole, assuming that a yet unknown gravitational theory in the UV does not introduce additional particle thresholds, as suggested by the tiny cosmological constant and the absence of new stabilizing physics at the EW scale. We find that, due to dimensional transmutation, the SM Higgs potential has a global minimum at 10^26 GeV, invalidating the SM as a phenomenologically acceptable model in this energy range. We show that extending the classically scale invariant SM with one complex singlet scalar S allows us to: (i) stabilize the SM Higgs potential; (ii) induce a scale in the singlet sector via dimensional transmutation that generates the negative SM Higgs mass term via the Higgs portal; (iii) provide a stable CP-odd singlet as the thermal relic dark matter due to CP-conservation of the scalar potential; (iv) provide a degree of freedom that can act as an inflaton in the form of the CP-even singlet. The logarithmic behavior of dimensional transmutation allows one to accommodate the large hierarchy between the electroweak scale and the Landau pole, while understanding the latter requires a new non-perturbative view on the SM.
COSMO-Seminar
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Nov 13 (Wed), 14:15 in A315
David Mulryne (Queen Mary)
Multiple field inflation: Methods and models
I will discuss inflation driven by more than one scalar field, which can be argued to be the generic situation. First I will review how the dynamics can change when more than one field is active during inflation, and then consider some popular two field models from the literature. I will discuss how simple techniques allow these models to be confronted by observations, and show how they are constrained by the recent Planck results. These simple techniques exploit the super-horizon ‘separate universe’ approximation to cosmological perturbation theory and are inadequate in many circumstances. Finally, therefore, I will discuss some recent work which aims to allow us to calculate all the observational signatures of multiple field models of inflation without recourse to these simplified methods.
VISITORS
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R. Foadi 4.11. – 19.11. (KT)
D. Mulryne, 11.11. – 16.11. (SN)
S. Niyogi 15.9.-15.12 (KH)
P. Pandita 4.11. – 21.11. (KH)
A. Racioppi, 11.11. – 13.11. (KT)
C. Royon, 11.11. – 14.11. (FD)
F. Sannino, 12.11. – 14.11. (KT)
Y. Schröder, 15.11. (KK)