Quantum Theory / Particle Physics
June 8, 2013
It is believed that Cockcroft and Walton’s experiment of disintegration of Li7 with swift protons yielding alpha particles confirmed DE=Dmc2 with reasonable accuracy. But reanalysis of data as given by Cockcroft in his Nobel Lecture confirms that above notion is not true. If we take current values of parameters (i.e. masses of proton, Li7, alpha particles), then %age difference is 9.768 MeV. The reason is that variation in magnitude of mass of Li7 at different times. At Cockcroft time it was 7.010 4amu, soon after it Bainbridge measured it as 7.0130amu and current value of mass of Li7 is 7.01600455 amu. Thus difference between values of masses of Li7 at Cockcroft’s time (1932) and now (2013) is 0.005604amu or 5.22 MeV. Thus it is suggested this classic and prospective experiment must be performed again.