Rare or newly observed decay events involving quarks and other subatomic particles in collider experiments.Quark decay processes are rare or newly observed transformations involving quarks, the fundamental building blocks of protons and neutrons. While quarks themselves are stable when bound inside hadrons, they can change flavor through the weak nuclear force, leading to decays of particles like the neutron or heavier mesons. Recent collider experiments have pushed the boundaries of what we know about these processes, searching for extremely rare decays that could reveal new physics beyond the Standard Model.
The theory of quark mixing was developed in the 1960s and 1970s by Cabibbo, Kobayashi, and Maskawa, but the observation of extremely rare quark decays has been a major experimental effort in the 21st century, with experiments like LHCb at CERN leading the search.
Quarks interact via the weak force, which can change one quark flavor into another (e.g., a 'down' quark into an 'up' quark). This is mediated by W bosons and is responsible for beta decay. In colliders, high-energy collisions create short-lived particles containing quarks, which then decay in characteristic patterns. By measuring the rates and products of these decays, physicists test the predictions of the Standard Model and look for deviations that might indicate new particles or forces.
These studies are fundamental to particle physics, helping to refine the Standard Model and search for physics beyond it. They also have indirect applications in cosmology, as quark processes influenced the early universe's evolution.
Some rare quark decays, like the decay of a B meson into a muon pair, occur only about once in a billion decays, making them incredibly difficult to catch even with billions of collisions.
