William Edward Caswell ( June 22 , 1947 &ndash; September 11 , 2001 ) was a physicist who died during the September 11 attacks , as a passenger aboard American Airlines Flight 77 , which was crashed into the Pentagon . Caswell did work in quantum gauge theory , most notably , his 1972 calculation of the beta function to two-loop accuracy . His pioneering work in the days of FORTRAN and punch cards demonstrated the potential of computer algebra
American Airlines Flight 77
American Airlines Flight 77
William E. Caswell