Quantum chromodynamics possess an additional SU(3) gauge degree of freedom, later called color charge. Han and Nambu noted that quarks might interact via an octet of vector gauge bosons: the gluons. Since free quark searches consistently failed to turn up any evidence for the new particles, and because an elementary particle back then was "defined" as a particle which could be separated and isolated, Gell-Mann often said that quarks were merely convenient mathematical constructs, not real particles. The meaning of this statement was usually clear in context: He meant quarks are confined, but he also was implying that the strong interactions could
Palash Baran Pal neutrino physics, Pal has done important work related to grand unification theory and statistical field theory (popularly called thermal field theory). Some of his works deal with the quantum field theoretic calculations of self-energies of photon and neutrino in a background of charged particles (as electrons, positrons or charged weak gauge bosons) in thermal equilibrium. Pal has also ventured into calculations where the background for various elementary particle processes includes a thermal bath of charged particles in presence of constant magnetic field. Palash Pal is also well known for his teaching and has taught various topics of modern physics in