Cosmological searches for the neutrino mass scale and mass ordering
Jul 18, 2019Citations per year
Abstract: (arXiv)
In this thesis, I describe a number of recent important developments in neutrino cosmology on three fronts. Firstly, focusing on Large-Scale Structure (LSS) data, I will show that current cosmological probes contain a wealth of information on the sum of the neutrino masses. I report on the analysis leading to the currently best upper limit on the sum of the neutrino masses of . I show how cosmological data exhibits a weak preference for the normal neutrino mass ordering because of parameter space volume effects, and propose a simple method to quantify this preference. Secondly, I will discuss how galaxy bias represents a severe limitation towards fully capitalizing on the neutrino information hidden in LSS data. I propose a method for calibrating the scale-dependent galaxy bias using CMB lensing-galaxy cross-correlations. Moreover, in the presence of massive neutrinos, the usual definition of bias becomes inadequate, as it leads to a scale-dependence on large scales which has never been accounted for. I show that failure to define the bias appropriately will be a problem for future LSS surveys, and propose a simple recipe to account for the effect of massive neutrinos on galaxy bias. Finally, I discuss implications of correlations between neutrino parameters and other cosmological parameters. In non-phantom dynamical dark energy models, the upper limit on the sum of the neutrino masses becomes tighter than the CDM limit. Therefore, such models exhibit an even stronger preference for the normal ordering, and their viability could be jeopardized should near-future laboratory experiments determine that the mass ordering is inverted. I then discuss correlations between neutrino and inflationary parameters. I find that our determination of inflationary parameters is stable against assumptions about the neutrino sector. (abridged)Note:
- Stockholm University PhD thesis, defended on June 10, 2019. Chapter 4 is a textbook-level review on neutrino cosmology, particularly suited for newcomers in the field. Advisor: Prof. Katherine Freese. Opponent: Prof. Alessandra Silvestri. ISBN: 978-91-7797-729-2. For full text on SU's website see http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-167815. Abstract severely abridged
- neutrinos
- neutrino mass
- neutrino mass ordering
- cosmology
- cosmic microwave background
- large-scale structure
- galaxy surveys
- dark energy
- cosmic inflation
- data analysis
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