Extending previous results, we explore aspects of the reheating mechanism for non-minimal Higgs inflation in the strong coupling regime. We constrain the radiative corrections for the inflaton's potential by considering the Coleman-Weinberg approximation and use the Renormalization Group Equations for the Higgs field to derive an upper limit on the top quark mass. Using the current Cosmic Microwave Background, Baryon Acoustic Oscillation, and Supernovae data, we obtain <math><msub><mrow><mi>m</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>≤</mo><mn>170.44</mn></math> GeV, confirming the observational compatibility of the model with recent <math><msub><mrow><mi>m</mi></mrow><mrow><mi>t</mi></mrow></msub></math> estimates reported by the CMS collaboration. We also analyze the breakdown of the well-known correlation involving the Hubble constant <math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math> and the clustering parameter <math><msub><mrow><mi>σ</mi></mrow><mrow><mn>8</mn></mrow></msub></math>, which makes the model interesting in light of the cosmological tensions discussed over the last decade.

Brazil

J.G. Rodrigues

Italy

M. Benetti

R. de Souza

J.S. Alcaniz

Higgs inflation: Constraining the top quark mass and breaking the - Correlation

We investigate the observational viability of a class of α-attractors inflationary models in light of the most recent Cosmic Microwave Background (CMB) and Large-Scale Structure (LSS) data. By considering a double-well potential we perform a slow-roll analysis to study the behavior of this class of models, which is a continuous interpolation between the chaotic inflation for large values of α and the universal attractor, i.e., <math><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>−</mo><mn>2</mn><mo>/</mo><mi>N</mi></math> and <math><mi>r</mi><mo>=</mo><mi>α</mi><mn>12</mn><mo>/</mo><msup><mrow><mi>N</mi></mrow><mrow><mn>2</mn></mrow></msup></math> for small α, where <math><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub></math> is the scalar spectral index, r is the tensor-to-scalar ratio, and N is the e-fold number. In order to explore the parameter space of the model, we also perform a MCMC analysis and find <math><mi>α</mi><mo>=</mo><mn>7.56</mn><mo>±</mo><mn>5.15</mn></math> (1σ).

S. Santos da Costa

Observational constraints on -attractor inflationary models with a Higgs-like potential

In this paper, new bounds on possible variations of the fine structure constant, α , for a class of runaway dilaton models are performed. By considering a possible evolution with redshift, z , such as Δαα=−γln⁡(1+z) , where in γ are the physical properties of the model, we constrain this parameter by using a deformed cosmic distance duality relation jointly with gas mass fraction (GMF) measurements of galaxy clusters and luminosity distances of type Ia supernovae. The GMF's used in our analyses are from cluster mass data from 82 galaxy clusters in the redshift range 0.12&lt;z&lt;1.36 , detected via the Sunyaev–Zeldovich effect at 148 GHz by the Atacama Cosmology Telescope. The type Ia supernovae are from the Union2.1 compilation. We also explore the dependence of the results from four models used to describe the galaxy clusters. As a result no evidence of variation was obtained.

R.F.L. Holanda

L.R. Colaço

R.S. Gonçalves

Limits on evolution of the fine-structure constant in runaway dilaton models from Sunyaev–Zeldovich observations