From Perimeter Institute: “The Case of the Shrinking Proton”

Perimeter Institute
Perimeter Institute

August 23, 2013

“Perimeter researchers Itay Yavin and Maxim Pospelov have posited a new force of nature to explain the seeming shrinking of the proton.

How big is the proton? For decades, this was a settled question. Then, in 2010, a new and better technique produced a new answer – one that contradicted decades of careful measurements. Two Perimeter researchers have an intriguing new suspect in the case of the shrinking proton: a new force of nature.

Before 2010, the size of the proton was so well defined and agreed upon that it joined the speed of light and the charge of the electron on the list of known quantities. But then, an international team of more than 30 researchers, led by Randolf Pohl and working at the Paul Scherrer Institute in Switzerland, announced a new measurement of the proton radius. Whereas the old measurement was 0.8768 femtometres, the new one was 0.841 femtometres. Although the difference was only a quadrillionth of an inch, the relative shift was huge – far larger than can be explained by experimental uncertainty.

So what happened? Theorists such as Perimeter Faculty members Itay Yavin and Maxim Pospelov have an intriguing idea – one that posits a new force of nature.

See the full article here.

About Perimeter

Perimeter Institute is a leading centre for scientific research, training and educational outreach in foundational theoretical physics. Founded in 1999 in Waterloo, Ontario, Canada, its mission is to advance our understanding of the universe at the most fundamental level, stimulating the breakthroughs that could transform our future. Perimeter also trains the next generation of physicists through innovative programs, and shares the excitement and wonder of science with students, teachers and the general public.