“Physical Review Letters” (2205) v. 95, 092001

In “Strange-Quark Contributions to Parity-Violating Asymmetries in the forward G0,” Wolfgang Korsch and other authors found a surprising effect related to the strange quarks inside the proton. Protons and neutrons, commonly called nucleons, contain three "permanent" quarks with fractional charges of +2/3 and -1/3 of the electron charge.  These quarks are confined to distances of 0.000000000000001 meters and move with speeds up to 99.99 percent of the speed of light. At such small distances quantum fluctuations occur. As a consequence quark — anti-quark pairs, i.e. an elementary form of matter and anti-matter — are constantly being created and annihilated. There are six different kinds of quarks and they each have different masses.  The two lightest ones — "up" and "down" quarks — constitute the "permanent" quarks in the nucleon. The next heaviest quark — the "strange" quark — is about 20 times heavier than the "up" and "down" quarks.

The G0 collaboration — comprised of more than 100 physicists — used parity violating electron scattering to explore the contribution of the "strange" quarks to the electric and magnetic properties of the proton. First results indicate that the strange and anti-strange quark distributions in the proton are not uniform. The data seems to imply an enhancement of strange quarks on the outside of the proton while the anti-strange quarks seem to favor the interior. However, higher precision data was needed to support this observation.

Wolfgang Korsch is an associate professor of physics in the College of Arts and Sciences at the University of Kentucky. He holds a doctorate in nuclear physics from the University of Marburg. His expertise includes intermediate energy nuclear physics, and his research interests include understanding the structure of nucleons.