If you’re feeling as if you’ve lost a bit of weight recently, blame physicists – recent calculations make the mass of the proton 30 billionths of a percent lighter than before.
Okay, so the sub-atomic particle hasn’t changed size, but new experiments have promoted a rethink on what the proton probably weighs. Strangely, while the new figure is three times more accurate than the previous one, nobody is sure why the new number is different. Similar to the Planck constant and the speed of light, the mass of the proton is a fundamental unit in physics. Last year, CERN came up with a new figure for antiproton masses that was in good agreement with previous proton mass measurements, leaving no room for CPT variation. There’s a slim chance future experiments might detect a tiny difference, but it’s unlikely that this change in proton mass is a sign of anything amazing.
We predict the proton diet will be the next big thing; lose 30 billionths of a percent without even trying.