Theory Division

In extreme astrophysical phenomena like supernova explosions, the large neutrino density can lead to collective flavor oscillations driven by neutrino-neutrino interactions. These phenomena can greatly modify flavor transport in these environments with potentially important consequences for both the explosion mechanism and nucleosynthesis in the ejected material. Even simple models of neutrino-neutrino interactions lead to a... More »

If our apparently four-dimensional spacetime is endowed with compact extra dimensions, our universe may not be entirely stable. It can decay, by the spontaneous nucleation of a “bubble of nothing”: a gravitational instanton that induces a catastrophic annihilation of spacetime. In this talk we discuss the connection between the bubble of nothing and an analogous Coleman-De... More »

The parameter $\epsilon_K$ is an important measure of the imbalance between matter and antimatter in the neutral kaon ($K^0$ and $\bar{K}^0$) system. In particular, $\epsilon_K$ provides a sensitive probe of new physics and plays a critical role in the global fit of the Cabibbo-Kobayashi-Maskawa matrix. As one of the first discovered sources of $CP$ violation,... More »

Dark photons are among the simplest extensions of the Standard Model (SM): a renormalizable kinetic mixing with the ordinary photons generates a coupling between the dark photon and the SM electromagnetic current. Such coupling can be used to probe the parameter space of the model, resulting in severe bounds. In this talk, I will discuss... More »

Do neutrinos have sizable self interactions? They might. As laboratory constraints are weak, strong effects can change our picture of astrophysical and cosmological environments. In this talk, I will explore the rich physics introduced by neutrino self-interactions throughout the Universe. I will discuss how a multidisciplinary approach, ranging from precision cosmology to neutrino telescopes, is... More »

Probing sub-GeV dark matter requires designing low threshold detectors and understanding backgrounds. In this talk I will address these two issues. First, we point out several unexplored low-energy backgrounds in sub-GeV dark matter searches, which arise from high-energy particles of cosmic or radioactive origin that interact with detector materials. In this talk, I will focus... More »

In this talk, I will present the first measurement of the neutron skin of cesium and iodine using electroweak probes, namely coherent elastic neutrino-nucleus scattering and atomic parity violation. This measurement, differently from hadronic probes, is model-independent and suggests a preference for nuclear models which predict large neutron skin values. Moreover, it permits to perform... More »

Neutrino self-interaction has been proposed as a solution to the Hubble tension, a discrepancy between the measured values of the Hubble constant from CMB and low-redshift data. However, flavor-universal neutrino self-interaction is highly constrained by BBN and laboratory experiments such as K-meson and tau decay, double-neutrino beta decay etc. In this talk, I will discuss... More »

When DM bosons have an ultra-light mass, they can act as a classical, coherent field. In many cases, and specifically in some ALP models, this field has magnetic properties, and it can therefore be measured by quantum magnetometers. The Noble and Alkali Spin Detectors for Ultralight Coherent darK matter (NASDUCK) collaboration, was formed last year... More »