## Journal Club

Seminar Room

### Monday 10th of June, 2019

# WIMPflation

(Submitted on 9 Jul 2018)

We propose a class of models in which a stable inflaton is produced as a thermal relic in the early universe and constitutes the dark matter. We show that inflaton annihilations can efficiently reheat the universe, and identify several examples of inflationary potentials that can accommodate all cosmic microwave background observables and in which the inflaton dark matter candidate has a weak scale mass. As a simple example, we consider annihilations that take place through a Higgs portal interaction, leading to encouraging prospects for future direct detection experiments.

presented by Antonio M.

# Modified Friedmann equations via conformal Bohm -- De Broglie gravity

(Submitted on 28 Apr 2019)

We use an alternative interpretation of quantum mechanics, based on the Bohmian trajectory approach, and show that the quantum effects can be included in the classical equation of motion via a conformal transformation on the background metric. We apply this method to the Robertson-Walker metric to derive a modified version of Friedmann's equations for a Universe consisting of scalar, spin-zero, massive particles. These modified equations include additional terms that result from the non-local nature of matter and appear as an acceleration in the expansion of the Universe. We see that the same effect may also be present in the case of an inhomogeneous expansion.

presented by Pawel K

# Same-sign WW Scattering in the HEFT: Discoverability vs. EFT Validity

(Submitted on 8 May 2019)

Vector boson scatterings are fundamental processes to shed light on the nature of the electroweak symmetry breaking mechanism. Deviations from the Standard Model predictions on the corresponding observables can be interpreted in terms of effective field theories, that however undergo consistency conditions. In this paper, the same-sign W W scattering is considered within the HEFT context and the correct usage of the effective field theory approach is discussed. Regions of the parameters space are identified where a signal of new physics could be measured at HL-LHC with a significance of more than 5σ and the effective field theory description is consistently adopted. These results are then translated into bounds on theξ parameter in the composite Higgs scenario. The discussion on the agreement with previous literature and the comparison with the equivalent analysis in the SMEFT case are also included.

presented by Pawel K.

#### All Dates

- 2024
- 2023
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- 2019
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- 2015
- 2014
- 2013