Electroweak baryogenesis above the electroweak scale
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Springer
Received: January 3, 2019 Accepted: March 29, 2019 Published: April 3, 2019
Electroweak baryogenesis above the electroweak scale
Theoretical Particle Physics Laboratory, Institute of Physics, EPFL, Lausanne, Switzerland
E-mail: [email protected], [email protected], [email protected] Abstract: Conventional scenarios of electroweak (EW) baryogenesis are strongly constrained by experimental searches for CP violation beyond the SM. We propose an alternative scenario where the EW phase transition and baryogenesis occur at temperatures of the order of a new physics threshold Λ far above the Fermi scale, say, in the 100–1000 TeV range. This way the needed new sources of CP-violation, together with possible associated flavor-violating effects, decouple from low energy observables. The key ingredient is a new CP- and flavor-conserving sector at the Fermi scale that ensures the EW symmetry remains broken and sphalerons suppressed at all temperatures below Λ. We analyze a minimal incarnation based on a linear O(N ) model. We identify a specific large-N limit where the effects of the new sector are vanishingly small at zero temperature while being significant at finite temperature. This crucially helps the construction of realistic models. A number of accidental factors, ultimately related to the size of the relevant SM couplings, force N to be above ∼ 100. Such a large N may seem bizarre, but it does not affect the simplicity of the model and in fact it allows us to carry out a consistent re-summation of the leading contributions to the thermal effective potential. Extensions of the SM Higgs sector can be compatible with smaller values N ∼ 20–30. Collider signatures are all parametrically suppressed by inverse powers of N and may be challenging to probe, but present constraints from direct dark matter searches cannot be accommodated in the minimal model. We discuss various extensions that satisfy all current bounds. One of these involves a new gauge force confining at scales between ∼ 1 GeV and the weak scale. Keywords: Beyond Standard Model, 1/N Expansion, Cosmology of Theories beyond the SM, Thermal Field Theory ArXiv ePrint: 1811.11740
c The Authors. Open Access, Article funded by SCOAP3 .
https://doi.org/10.1007/JHEP04(2019)027
JHEP04(2019)027
Alfredo Glioti, Riccardo Rattazzi and Luca Vecchi
Contents 1 Introduction low energy sector Avoiding sphaleron washout A model Thermal vacuum dynamics in first approximation 3D or not 3D? The effective potential
4 4 6 9 11 15
3 Phenomenology 3.1 Collider constraints 3.2 Dark matter constraints and simple fixes 3.2.1 Extension 1: adding a dark matter candidate 3.2.2 Extension 2: breaking O(N ) softly 3.3 A more ambitious fix: confining S and composite dark matter 3.3.1 Reannihilation after confinement and Sglueball dark matter 3.3.2 An extension with mesonic dark matter
22 22 24 26 27 28 30 33
4 Comments on alternative models 4.1 Large-N models 4.2 Models with smaller N
34 34 35
5 Electro-weak baryogenesis at Tc 100 GeV 5.1 Weakly-coupled sec
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