Mesons

            Over the years an important aspect of molecular science has been to better understand the phenomena that are observed in the properties of fundamental particles. One fundamental particle that has come under much observation in just the last few decades is the meson. The observation and studying of mesons have lead to a much better understanding of fundamental particles and will continue to help explain the still unknown aspects of fundamental particles. .
             Mesons were unknown to the science world until their discovery in 1934 by Hideki Yukawa (Gamow 152). Yukawa, a Japanese physicist, predicted the existence of mesons in a theoretical investigation of nuclear forces. He theorized that if the interactions cannot be explained by forces that come from the jumping of electron-neutrino pairs then there must be some other particle that does the jumping (Waller 1). This hypothetical particle was known as a Yukon, a Japanese electron, a heavy electron, a mesotron, and finally, as it is known today, a meson (Waller 1). A meson is a strongly interacting particle that is made up of a quark and an anti-quark and has an even integer spin (Gamow 152). Mesons are particles that are heavier than electrons, but lighter than protons (Waller 1). Their actual mass is about 200 times that of an electron and about ten times less than a proton. .
             Yukawa's theories on the existence of mesons got its first experimental evidence in 1937 from Anderson and Neddermeyer. Their experiment, performed at the California Institute of Technology, found particles with a mass 207 times greater than the electrons were cosmic rays (Waller 1). This step towards evidence of mesons was followed by a slight setback in Yukawa's theory when Converi, Pancini, and Piccioni performed an experiment that found that although the new particles had the mass of Yukawa's mesons, their interaction with nucleons was not enough to explain the nuclear forces.