The isospin and strangeness determine this quantity for hadrons in a formula developed by Okubo and Gell-Mann. When this quantity equals zero, the Dirac equation reduces to the Weyl [vile] equation. Spontaneous symmetry breaking creates (15[1])bosons with a zero value of this quantity according to Goldstone’s (15[1])theorem. In a formula named for this quantity, Coulomb, asymmetry, and pairing terms are used to represent the liquid drop model; that (*) “semi-empirical” formula is (10[1])used to calculate the nucleus’s namesake “defect” in this quantity. A (10[1])Millennium Prize problem involves determining whether Yang-Mills theory has a “gap” in this quantity. Kinetic energy equals momentum squared over 2 times this quantity. For 10 points, Albert Einstein stated that what quantity equals energy over the speed of light squared? ■END■