Hartland Sweet Snyder was a physicist

Physicist

A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

 who along with Robert Oppenheimer

Robert Oppenheimer

Julius Robert Oppenheimer was an American theoretical physicist and professor of physics at the University of California, Berkeley. Along with Enrico Fermi, he is often called the "father of the atomic bomb" for his role in the Manhattan Project, the World War II project that developed the first...

 calculated the gravitational collapse of a pressure-free homogenous fluid sphere, and found that it could not communicate with the rest of the universe.

In 1955, he bet against Maurice Goldhaber

Maurice Goldhaber

Maurice Goldhaber was an Austrian-born American physicist, who in 1957 established that neutrinos have negative helicity.-Early Life and Childhood:...

 that antiprotons

Antiproton

The antiproton is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived since any collision with a proton will cause both particles to be annihilated in a burst of energy....

 existed, and won.

The paper:

Ernest Courant

Ernest Courant

Ernest Courant has been called the "father of modern particle accelerators". A fundamental contributor to the field, he has also been mentor to several generations of students...

 and Snyder (2000) "The Theory of the Alternating-Gradient Synchrotron," Annals of Physics 281(1): 360-408(49).

laid the foundations for the field of accelerator physics. In particular, Hartland with Courant and M. Stanley Livingston developed the principle of strong focusing that made modern particle accelerators possible.