2,588 research outputs found
Distinguishing between R^2-inflation and Higgs-inflation
We present three features which can be used to distinguish the R^2-inflation
Higgs-inflation from with ongoing, upcoming and planned experiments, assuming
no new physics (apart form sterile neutrinos) up to inflationary scale. (i)
Slightly different tilt of the scalar perturbation spectrum n_s and ratio r of
scalar-to-tensor perturbation amplitudes. (ii) Gravity waves produced within
R^2-model by collapsing, merging and evaporating scalaron clumps formed in the
post-inflationary Universe. (iii) Different ranges of the possible Standard
Model Higgs boson masses, where the electroweak vacuum remains stable while the
Universe evolves after inflation. Specifically, in the R^2-model Higgs boson
can be as light as 116 GeV. These effects mainly rely on the lower reheating
temperature in the R^2-inflation.Comment: 10 pages, updated to match the journal version (various
clarifications added compared to v1
The Planck and LHC results and particle physics
I will discuss the recent LHC and Planck results, which are completely
compatible with the Standard Model of particle physics, and the standard
cosmological model (CDM), respectively. It turns out that the
extension of the Standard Model is, of course, required, but can be very
minimal. I will discuss also what future measurements may be important to test
this approach.Comment: 7 pages, talk on the EPS-HEP 2013 prepared for conference proceeding
Unitarizing Higgs Inflation
We consider a simple extension of the Standard Model Higgs inflation with one
new real scalar field which preserves unitarity up to the Planck scale. The new
scalar field (called sigma) completes in the ultraviolet the theory of Higgs
inflation by linearizing the Higgs kinetic term in the Einstein frame, just as
the non-linear sigma model is unitarized into its linear version. The unitarity
cutoff of the effective theory, obtained by integrating out the sigma field,
varies with the background value of the Higgs field. In our setup, both the
Higgs field and the sigma field participate in the inflationary dynamics,
following the flat direction of the potential. We obtain the same slow-roll
parameters and spectral index as in the original Higgs inflation but we find
that the Hubble rate during inflation depends not only on the Higgs
self-coupling, but also on the unknown couplings of the sigma field.Comment: 16 page
Why should we care about the top quark Yukawa coupling?
In the cosmological context, for the Standard Model to be valid up to the
scale of inflation, the top quark Yukawa coupling should not exceed the
critical value , coinciding with good precision (about 0.02%) with
the requirement of the stability of the electroweak vacuum. So, the exact
measurements of may give an insight on the possible existence and the
energy scale of new physics above 100 GeV, which is extremely sensitive to
. We overview the most recent theoretical computations of and
the experimental measurements of . Within the theoretical and experimental
uncertainties in the required scale of new physics varies from GeV
to the Planck scale, urging for precise determination of the top quark Yukawa
coupling.Comment: 9 pages, 8 figures. The journal version in JETP special issue. Some
discussion is improved, references added, and (here we reluctantly followed
the editorial request) the abstract is expande
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