Title: Probing Fundamental Theories & Reheating Cosmology with Cosmic Millicharge Background
Abstract: Exploring millicharged particles (particles with small rational or irrational charges) has become a central focus in contemporary particle physics and cosmology. Linked to charge quantization, which spurred Dirac Quantization and Grand Unification Theories, the millicharge searches are also a testing grounds for string theory and quantum gravity. I will give a general introduction to millicharged particles and present a novel approach to leverage them for probing reheating cosmology—a pivotal phase post-inflation, shaping the current Universe's particle composition. Millicharge searches offer insights into reheating scenarios and temperatures. I will also discuss the irreducible cosmic millicharged background and implications on the dark matter observations, the 21-cm absorption spectrums, Big Bang nucleosynthesis, and CMB measurements.
Finally, the talk delves into dedicated experimental efforts, notably the FORMOSA experiment at CERN, LANSCE-mQ at LANL, and neutrino experiments at Fermilab, which may help unveil the mysteries in cosmology and fundamental theories.
