Chinese theoretical physicist (born 1922) who made significant contributions to statistical mechanics, integrable systems, gauge theory, particle physics, and condensed matter physics; he became the first Chinese recipient of the Nobel Prize in 1957. ALS signed “Frank,” two pages, 8.5 x 11, no date but postmarked July 23, 1953. Handwritten scientific letter to Professor Joaquin M. Luttinger at UC Berkeley, regarding ongoing research in physics at Brookhaven National Laboratory. In part: "Sorry for not having written you earlier. I had hoped to write you after I get the manuscript ready, but it looks as if this may still take some more time, so I am writing you now. The paper is difficult to write, and I do wish to say more about justifying the approximation we made. I promise to get it done in another two weeks. O.K. (?)
As a compensation, and in exchange for your acceptance of my apologies, I shall offer you here some information about what goes on at Brookhaven. They have here a 1.5 Bev Π- beam and a neutron beam of an extended spectrum all the way to 2.2 Bev. Experiments have been done with H2 cloud chambers, emulsions & counters in these beams. You probably already know the result that Π+ + H total σ ≡ 35 mb. at 500 Mev. & 1.5 Bev. This seems to indicate, to-gether with cosmic ray data, that in these high energy events Fermi’s statistical theory is quite correct.
Some V’s have been found in the neutron beam, (a few). But the most exciting news are those found in the 1.5 Bev Π- beam, because here the incoming energy is known & the H2 cloud chamber pictures with a magnetic field really give you a lot of information. Two pictures of the sketched type have been found. All angle & momenta measurements indicate AB is a Vo with Q ≡ 50 Mev. Assuming the reaction to be:
Π- + H → Vo + ?
↑ one neutral particle
One finds
M? = 350 ± 70 } in one case
= 1270 ± 70 } in another case.
The production σ for this process seems to be ~ a few mb which is extremely large considering the fact that the Vo & ? have very little K.E. in the c. of m. centre of mass system. A holiday spirit prevails here among the theorists, of which there are many: Sachs, Fermi (gone now), Kroll, Goldberger, Van Hove, Berlin, Goldstein, Ruderman, Henley, Foldy, Christian, Noyes, etc. What’s new in California?” In fine condition, with intersecting folds. Accompanied by the original mailing envelope, addressed in Yang's hand and incorporating his name ("C. N. Yang") in the return address.
Yang penned this letter while conducting research at the Brookhaven National Laboratory on Long Island. It was during this period that he, with Robert Mills, developed non-abelian gauge theory, widely known as the Yang-Mills theory—perhaps his most well-known and important contribution to physics. This fascinating letter outlines, in complex technical detail, some of the ongoing research at Brookhaven, and, at the conclusion, makes reference to several of the physics luminaries affiliated with the laboratory. Among those mentioned are Enrico Fermi, Robert G. Sachs, Norman Myles Kroll, Marvin Goldberger, Leon Van Hove, Herbert Goldstein, Leslie Foldy, and H. Pierre Noyes.