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Francesca Rosati

Publications and source records attributed to Francesca Rosati.

11 recordsLinked to original sources
arXiv2005

Cosmological evolution of Alpha driven by a general coupling with Quintessence

A general model for the cosmological evolution of the fine structure constant αdriven by a typical Quintessence scenario is presented. We consider a coupling between the Quintessence scalar ϕand the electromagnetic kinetic term F^2, given by a general function B_F(ϕ). We study the dependence of the cosmological Δα(t) upon the functional form of B_F and discuss the constraints imposed by the data. We find that different cosmological histories for Δα(t) are possible within the avaliable constraints. We also find that Quasar absorption spectra evidence for a time variation of alpha, if confirmed, is not incompatible with Oklo and meteorites limits.

astro-ph↗
arXiv2005

Possible influence of Dark Energy on the Dark Matter Relic Abundance

Although a direct interaction between WIMP CDM candidates and scalar Quintessence fields (sources of Dark Energy) poses severe phenomenological threats, yet it is possible that the presence of Quintessence produces profound deviations in the expansion rate of the early Universe at the moment of WIMP decoupling, hence causing significant enhancements of the relic DM abundance. We consider the occurrence of such a phenomenon in a couple of physically interesting situations, kination and scalar-tensor theories of gravity where the scalar component plays the role of Quintessence. The consequences for supersymmetric DM candidates are briefly discussed.

astro-ph↗
arXiv2004

Dark Energy and the Dark Matter relic abundance

Two mechanisms by which the Quintessence scalar could enhance the relic abundance of dark matter particles are discussed. This effect can have an impact on supersymmetric candidates for dark matter.

astro-ph↗
arXiv2000

Can the Inflaton and the Quintessence scalar be the same field?

The most recent cosmological data point in the direction of a cosmological constant dominated universe. A suitable candidate for providing the required acceleration is a rolling scalar field named ``quintessence''. We address the issue of building a particle physics model for quintessence in the context of Susy QCD. We then go on to ask if the quintessence scalar can be identified with the inflaton field and give two examples in which this is indeed the case.

hep-ph↗
arXiv1999

On the Construction of Quintessential Inflation Models

Attention has been recently drawn towards models in which inflation and quintessence schemes are unified. In such `quintessential inflation' models, a unique scalar field is required to play both the role of the inflaton and of the late-time dynamical cosmological constant. We address the issue of the initial conditions for quintessence in this context and find that, in the two explicit examples provided, inflation can uniquely fix them to be in the allowed range for a present day tracking.

hep-ph↗
arXiv1999

Quintessence, Supersymmetry and Inflation

Recent data point in the direction of a $Λ$ dominated universe. We briefly review ``Quintessence'' as a model for a dynamical cosmological term and analyse the role of Susy QCD as a possible particle physics candidate. The multiscalar content of the theory is fully taken into account and interaction with other cosmological fields is discussed. Finally, the possibility of constructing a unified scheme for quintessence and inflation is mentioned.

hep-ph↗
arXiv1999

Supersymmetric Quintessence

Recent data point in the direction of a cosmological constant dominated universe. We investigate the role of supersymmetric QCD with N_f < N_c as a possible candidate for dynamical cosmological constant (``quintessence''). We take in full consideration the multi-scalar nature of the model, allowing for different initial conditions for the N_f independent scalar VEVs and studying the coupled system of N_f equations of motion. The issues related to the coupling of the scalars with other cosmological fields are also addressed.

hep-ph↗
arXiv1999

Breakthroughs on the Dark Matter Issue

Last year observations had a profound impact on our views on the amount and nature of dark matter in the universe. We give a brief review of the recent history of dark matter models beyond the pure cold dark matter universe. In view of the most recent cosmological data, we then go on to discuss models with a positive cosmological constant. Finally we explicitly analyse a class of particle physics models for a dynamical cosmological component with negative pressure (``quintessence''), in the context of supersymmetric theories.

hep-ph↗
arXiv1999

SUSY QCD and Quintessence

Recent data point in the direction of a cosmological constant dominated universe. We investigate the role of supersymmetric QCD with N_f < N_c as a possible candidate for dynamical cosmological constant (``quintessence''). When N_f > 1, the multiscalar dynamics is fully taken into account, showing that a certain degree of flavor symmetry in the initial conditions is necessary in order to attain the required late-time ``tracking'' attractor behavior. A possible solution to the problem of long-range interactions of gravitational strength is proposed. Finally we show how, as a consequence of the interaction with the Standard Model fields, the early cosmological evolution of the scalar fields may be dramatically altered, and the approach to the tracking behavior may become much more efficient.

hep-ph↗