Lyndon B. Johnson Lyndon B. Johnson Lyndon Baines Johnson (; August 27, 1908January 22, 1973), often referred to by his initials LBJ, was an American politician who served as the 36th President of the United States from 1963 to 1969. Formerly the 37th Vice President of the United States from 1961 to 1963, he assumed the presidency following the assassination of President John F. Kennedy. A Democrat from Texas, Johnson also served as a United States Representative and as the Majority Leader in the United States Senate. Johnson is one of only four people who have served in all four federal elected positions.
B − L B − L In high energy physics, B" − "L (pronounced "bee minus ell") is the difference between the baryon number ("B") and the lepton number ("L"). This quantum number is the charge of a global/gauge U(1) symmetry in some Grand Unified Theory models, called U(1). Unlike baryon number alone or lepton number alone, this hypothetical symmetry would not be broken by chiral anomalies or gravitational anomalies, as long as this symmetry is global, which is why this symmetry is often invoked. If exists as a symmetry, it has to be spontaneously broken to give the neutrinos a nonzero mass