Neutrino decay modifies neutrino propagation in a unique way; not only is there flavor changing as there is in neutrino oscillations, there is also energy transport from initial to final neutrinos. The most sensitive direct probe of neutrino decay is currently IceCube which can measure the energy and flavor of neutrinos traveling over extragalactic distances. For the first time we calculate...
A precise characterization of the astrophysical neutrino flux is feasible as neutrino telescopes collect data. IceCube has already measured the spectral shape and flavor composition of this flux. Several projected experiments will be able to further constrain the nature of cosmic neutrinos. Most of these experiments look for neutrinos that cross the Earth, so it is fundamental to understand...
Neutrinos passing through the Earth can scatter off nuclei and produce heavy neutral leptons (HNLs). For HNL decay lengths on the order of, or shorter than, the radius of the Earth these HNLs can be efficiently detected by searching for their decay products in large volume detectors. I will discuss prospects for discovery of HNLs produced from solar and atmospheric neutrinos in large volume detectors.
The pp-chain of nuclear reactions is the primary route for energy production in the Sun. The first step in that reaction sequence converts two protons to a deuterium nucleus with the emission of a positron and electron neutrino. This reaction is extremely slow because it is a weak interaction, and significantly, it involves quantum tunneling through the Coulomb barrier. Though the reaction...
Heavy stars can explode at their ends. This phenomenon is called supernova. Supernovae are very complicated systems so we need high cost computation to understand them. Supernovae release a lot of neutrinos at their explosion. If a supernova happens in our galaxy, a few thousands events could be detected with neutrino detectors in the world for about more than 10 seconds. We need long time...
The formation of ultra rare supermassive black holes (SMBHs), with masses of $\ord{10^9 M_{odot}}$, in the first billion years of the Universe remains an open question in astrophysics. At the same time, ultralight dark matter (DM) with mass in the vicinity of $\ord{10^{-20}~\text{eV}}$ has been motivated by small scale DM distributions. Though this type of DM is constrained by various...
Observations of high-energy astrophysical neutrinos in IceCube have opened the door to multi-messenger astronomy, by way of which questions in particle physics could be explored through a combination of IceCube data and optical experiments such as Fermi-LAT. However, the origin of these astrophysical neutrinos is still largely unknown. Among the tensions that still need to be addressed, for...
The discovery of a non-zero mass for neutrinos invites to consider whether they are Dirac or Majorana particles. But those are not the only two possibilities, there is a third one, in which neutrinos are Majorana, but they behave as if they were Dirac particles, that is called pseudo-Dirac particles. The scenario predicts an oscillation between active and sterile neutrinos, with an oscillation...
The IceCube neutrino observatory is the to-date largest neutrino telescope installed in the Antarctic ice. It consists of 5,160 photomultiplier-tubes spread among 86 vertical strings making a total detector volume of more than a cubic kilometer. It detects neutrinos via Cherenkov light of charged relativistic particles from neutrino interactions with the detector volume. IceCube is, due to its...
We forecast constraints on neutrino decay via capture of the Cosmic Neutrino Background (CνB) on tritium, with emphasis on the PTOLEMY-type experiment. Although direct observations of the CνB are still in their very early stages, future direct observations of the CνB will impose significant constraints on a neutrino lifetime in the region of the age of the universe. We discuss the would-be...
The latest results from a search for the Diffuse Supernova Neutrino Background (DSNB) at Super-Kamiokande (SK) is presented, incorporating 22.5×2970 kton.days of data from its fourth data-taking phase, covering an overall antineutrino energy range of 9.3−81.3 MeV, and combining results with previous SK data-taking periods, for a combined analysis of nearly 20 years of data. The analysis...
A possible sub-leading effect originating from new physics beyond the Standard Model may affect the propagation of neutrinos. In this talk, we shall discuss the potential to prove light extra gauge Z boson inducing neutrino non-standard interactions (NSIs) in the coherent-elastic neutrino-nucleus scattering (CEνNS) experiments. Also, we shall explore the possibility of having a fermionic dark...
