Core-collapse Supernova Constraint on the Origin of Sterile Neutrino Dark Matter via Neutrino Self-interactions

Novel neutrino self-interaction can open up viable parameter space for therelic abundance of sterile-neutrino dark matter (S$\nu$DM). In this work, weconstrain the relic target using core-collapse supernova which features thesame fundamental process and a similar environment to the early universe erawhen S$\nu$DM is dominantly produced. We present a detailed calculation of theeffects of a massive scalar mediated neutrino self-interaction on the supernovacooling rate, including the derivation of the thermal potential in the presenceof non-zero chemical potentials from plasma species. Our results demonstratethat the supernova cooling argument can cover the neutrino self-interactionparameter space that complements terrestrial and cosmological probes.<br

Hierarchies of Susy Splittings and Invisible Photinos as Dark Matter

We explore how to generate hierarchies in the splittings between superpartners. Some of the consequences are the existence of invisible components of dark matter, new inflaton candidates, invisible monopoles and a number of invisible particles that might dominate during various eras, in particular between BBN and recombination and decay subsequently.Comment: 16 pages. v3: Ref. 27 has been modified. v4: Published versio

Holographic Brownian Motion in Magnetic Environments

Using the gauge/gravity correspondence, we study the dynamics of a heavy quark in two strongly-coupled systems at finite temperature: Super-Yang-Mills in the presence of a magnetic field and non-commutative Super-Yang-Mills. In the former, our results agree qualitatively with the expected behavior from weakly-coupled theories. In the latter, we propose a Langevin equation that accounts for the effects of non-commutativity and we find new interesting features. The equation resembles the structure of Brownian motion in the presence of a magnetic field and implies that the fluctuations along non-commutative directions are correlated. Moreover, our results show that the viscosity is smaller than the commutative case and that the diffusion properties of the quark are unaffected by non-commutativity. Finally, we compute the random force autocorrelator and verify that the fluctuation-dissipation theorem holds in the presence of non-commutativity.Comment: 34 pages. v2: typos corrected. v3: title and abstract slightly modified in order to better reflect the contents of the paper; footnote 3 and one reference were also added; version accepted for publication in JHE

Neutrino Self-Interactions: A White Paper

Neutrinos are the Standard Model (SM) particles which we understand theleast, often due to how weakly they interact with the other SM particles.Beyond this, very little is known about interactions among the neutrinos, i.e.,their self-interactions. The SM predicts neutrino self-interactions at a levelbeyond any current experimental capabilities, leaving open the possibility forbeyond-the-SM interactions across many energy scales. In this white paper, wereview the current knowledge of neutrino self-interactions from a vast array ofprobes, from cosmology, to astrophysics, to the laboratory. We also discusstheoretical motivations for such self-interactions, including neutrino massesand possible connections to dark matter. Looking forward, we discuss thecapabilities of searches in the next generation and beyond, highlighting thepossibility of future discovery of this beyond-the-SM physics.<br

Dodelson-Widrow Mechanism in the Presence of Self-Interacting Neutrinos

keV-scale gauge-singlet fermions, when allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early Universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting x-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. Here, we show that new interactions among the active neutrinos allow these sterile neutrinos to make up all the DM while safely evading all current experimental bounds. The existence of these new neutrino interactions may manifest itself in next-generation experiments, including DUNE