Neutrinos, though nearly invisible, are among the most numerous matter particles in the universe. The Standard Model recognizes three types, but the discovery of neutrino oscillations revealed they have mass and can change identity while propagating.
For decades, puzzling experimental anomalies have suggested the presence of a fourth, “sterile” neutrino, one that interacts even more weakly. Finding it would transform our understanding of particle physics.
SUNY Poly Professor of Physics Dr. Amir Fariborz recently published a paper in Physical Review D titled “Spinless glueballs in generalized linear sigma model.” The work takes on a central challenge in modern physics: understanding how the strongest force in nature shapes the inner structure of matter, and how it may produce an unusual form of matter made entirely from the carriers of that force.
Here’s the quick background. Everything is made of atoms. Atoms have a nucleus made of protons and neutrons, and those are made of even smaller pieces called quarks. Quarks are held together by gluons, which carry the strong interaction described by quantum chromodynamics (QCD).
Composite subatomic particles—hadrons—are built from quarks and gluons. Hadrons fall into two main groups: mesons and baryons. QCD does a great job explaining what happens when particles collide at very high energies, but at lower energies it becomes much harder to calculate, so researchers use well-tested models that still follow QCD’s rules.
Measurements of the decay of the Higgs boson into muon–antimuon pairs provide evidence for the mechanism by which quarks and leptons acquire their mass.
The most basic bits of matter that we have found are quarks and leptons, which we idealize as point-like objects with no internal structure and no measurable size (experiments constrain their sizes to below an attometer, a billionth of a billionth of a meter). The quarks, which experience strong, weak, and electromagnetic interactions, come in six flavors: up and down (the constituents of the proton and neutron), charm and strange, and top and bottom. The charged leptons—electron, muon, and tau—experience weak and electromagnetic interactions, while the neutral leptons—the three neutrinos—feel only the weak interactions. The masses of the quarks and charged leptons span more than 5 orders of magnitude: The top-quark mass is nearly 340,000 times that of the electron.
