11:00 am
In-Person and Virtual Kersten Physics Teaching Center, Room 106
Join us for a free public lecture series celebrating 50 Years of Discovery at the Enrico Fermi Institute of UChicago. Attendees can join in person or virtually.
Prof. Marcela Carena presents: Broken Symmetries and the Origins of Mass and Matter
Broken symmetries in Nature underpin our understanding of many materials, from ferromagnets to superconductors. In the 1960s UChicago professor Yoichiro Nambu had the bold insight that because empty space is not really empty, the quantum vacuum can break symmetries. Peter Higgs then proposed that an invisible quantum field fills the universe, breaking symmetry and giving mass to elementary particles. Higgs’ idea was dramatically confirmed by the discovery of the Higgs boson particle at CERN, raising the even deeper question of how the Higgs field turned on instants after the Big Bang. A related mystery is the breaking of charge-parity (CP) symmetry linking matter and antimatter, first revealed in the decay of K mesons. Explaining CP violation in the Standard Model required both the Higgs field and a third generation of quarks, confirmed by the discovery of the bottom and top quarks at Fermilab. This CP violation could have explained why more matter than antimatter was produced in the early universe, through a process called electroweak baryogenesis. However, the measured CP violation gives a result roughly ten billion times too small and the discovered Higgs boson is too heavy, implying that new particles and new forces are required for electroweak baryogenesis to work. The full story must have more ingredients, perhaps involving dark matter or neutrinos. Future experiments may finally shed light to why there is matter rather nothing – and why we exist.