Francesco L. Villante

STRUCTURE FORMATION WITH MIRROR DARK MATTER: CMB AND LSS

In the mirror world hypothesis, the mirror baryonic component emerges as a possible dark matter candidate. An immediate question arises: how do the mirror baryons behave and what are their differences from the more familiar dark matter candidates such as cold dark matter? In this paper, we answer this question quantitatively. First, we discuss the dependence of the relevant scales for the structure formation (Jeans and Silk scales) on the two macroscopic parameters necessary to define the model: the temperature of the mirror plasma (limited by the Big Bang Nucleosynthesis) and the amount of mirror baryonic matter. Then we perform a complete quantitative calculation of the implications of mirror dark matter on the cosmic microwave background and large scale structure power spectrum. Finally, confronting with the present observational data, we obtain some bounds on the mirror parameter space.

The Chemical Composition of the Sun from Helioseismic and Solar Neutrino Data

We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseismic and solar neutrino data in an effective way. We include in our analysis the helioseismic determinations of the surface helium abundance and of the depth of the convective envelope, the measurements of the 7 Be and 8 B neutrino fluxes, and the sound speed profile inferred from helioseismic frequencies. We provide all the ingredients to describe how these quantities depend on the solar surface composition, different from the initial and internal composition due to the effects of diffusion and nuclear reactions, and to evaluate the (correlated) uncertainties in solar model predictions. We include error sources that are not traditionally considered such as those from inversion of helioseismic data. We, then, apply the proposed approach to infer the chemical composition of the Sun. Our result is that the opacity profile of the Sun is well constrained by the solar observational properties. In the context of a two-parameter analysis in which elements are grouped as volatiles (i.e., C, N, O, and Ne) and refractories (i.e., Mg, Si, S, and Fe), the optimal surface composition is found by increasing the abundance of volatiles by (45 ± 4)% and that of refractories by (19 ± 3)% with respect to the values provided by Asplund et al. (2009, ARA&A, 47, 481). This corresponds to the abundances eO = 8.85 ± 0.01 and eFe = 7.52 ± 0.01, which are consistent at the ∼1σ level with those provided by Grevesse & Sauval (1998, SSRv, 85, 161). As an additional result of our analysis, we show that the best fit to the observational data is obtained with values of input parameters of the standard solar models (radiative opacities, gravitational settling rate, and the astrophysical factors S34 and S17) that differ at the ∼1σ level from those presently adopted.

A new Generation of Standard Solar Models

We compute a new generation of standard solar models (SSMs) that includes recent updates on some important nuclear reaction rates and a more consistent treatment of the equation of state. Models also include a novel and flexible treatment of opacity uncertainties based on opacity kernels, required in the light of recent theoretical and experimental works on radiative opacity. Two large sets of SSMs, each based on a different canonical set of solar abundances with high and low metallicity (Z), are computed to determine model uncertainties and correlations among different observables. We present detailed comparisons of high- and low-Z models against different ensembles of solar observables including solar neutrinos, surface helium abundance, depth of convective envelope and sound speed profile. A global comparison, including all observables, yields a p-value of 2.7

The cosmological 7Li problem from a nuclear physics perspective

\sigma

New axion and hidden photon constraints from a solar data global fit

for the high-Z model and 4.7

Implications of solar wind measurements for solar models and composition

\sigma

Expectations for high energy diffuse galactic neutrinos for different cosmic ray distributions

for the low-Z one. When the sound-speed differences in the narrow region of

Phase space mass bound for fermionic dark matter from dwarf spheroidal galaxies

0.65 < r/R_{sun} < 0.70

Helioseismic and neutrino data-driven reconstruction of solar properties

are excluded from the analysis, results are 0.9

The galactic diffuse high energy neutrino flux

\sigma