Title: On the Dynamical Origin of the η′ Potential and the Axion Mass Abstract: The standard lore posits that pure QCD dynamics generates a confining potential with a branched structure as a function of the θ angle. This same potential also largely determines the properties of the η′, the (would-be) Goldstone boson associated with the anomalous axial U(1) symmetry of QCD, … Read More
The axion is a strongly theoretically motivated particle. The axion coupling to electromagnetism leads tomany interesting phenomena, providing possibilities for their direct or indirect detection. On the direct detectionside, we propose a new experimental target: axions emitted in the magnetosphere of pulsars. The signal is emittedat the pulsar rotation frequency and is highly coherent. Thus, experimental searches benefit from a … Read More
Abstract: Axions and axion-like particles may couple to nuclear spins like a weak oscillating effective magnetic field, the “axion wind.” Existing proposals for detecting the axion wind sourced by dark matter exploit analogies to nuclear magnetic resonance (NMR) and aim to detect the small transverse field generated when the axion wind resonantly tips the precessing spins in a polarized sample of … Read More
Singlet scalars, namely axion-like particles (ALPs), are among the most promising candidates of new physics. Standard (minimal) assumptions in the study of these particles might however hide a large landscape of solutions to different puzzles in the SM, which can limit our discovery potential. In the first part of the talk, I will consider the impact of scalar mixing … Read More
Abstract:As the WIMP draws under increasing tension thanks to the ever increasing sensitivity of direct detection experiments, the majority of dark matter parameter space outside of the weak scale remains unexplored. Molecular and nano-scale systems are particularly well-suited to look for sub-GeV DM since their eV-scale electronic transitions may be excited through light dark matter interactions. In this seminar, will … Read More
Abstract: Pulsar timing arrays (PTAs) and gravitational wave detectors can serve as valuable tools in the detection of dark matter. Dark matter substructure within the Milky Way Galaxy can induce gravitational pulls on pulsars, leading to observable deviations in pulsar timings. We demonstrate that dark matter models predicting enhanced power on small scales (<pc) are potentially within the reach of … Read More
Given that axions are both a promising candidate to solve problems in the Standard Model and are ubiquitous in quantum gravity, it is crucial to accurately determine their signatures. In this talk, we discuss how the axion’s compact field space leads to interesting interactions with topological defects, specifically monopoles and strings. In the case of monopoles, we show that, due … Read More
Abstract: Axions and ALPs are among the best motivated extensions of of the Standard Model. In this talk we discuss how ALP parameters at the UV scale relate to those at the lower energies of experiments, and show that regardless the specific UV coupling configuration a plethora of low-energy couplings is generated, including flavour-changing ones. This then allows us to … Read More
Recent observations have granted to us two unique insights into the early universe: the presence of a low-frequency stochastic gravitational wave background detected by the NANOGrav and Pulsar Timing Array (PTA) experiments and the emergence of unusually massive galaxy candidates at high redshifts reported by the James Webb Space Telescope (JWST). In this talk, I will consider the possibility that … Read More
https://lbnl.zoom.us/j/94928022788?pwd=emVQWG1mTnhSbHVqekVuenk0VEVQZz09 Abstract: Pioneered in the 1950s by Hanbury Brown and Twiss, intensity interferometry refers to the correlation of light intensities incident on two telescopes. As its name suggests, it relies only on photon counting, allowing for interferometry with arbitrarily long baselines in optical wavelengths. Its chief drawbacks are the need for very bright sources and a limited field-of-view, and is thus … Read More