QNAS QnAs with Burton Richter

Paul Gabrielsen Science Writer

Forty years ago, on November 11, 1974, Burton Tuesday with a copy of the paper to Physical Richter of Stanford University and the Stanford Review Letters (1). Linear Accelerator Center (SLAC) and Samuel PNAS: The work and its aftermath have C. C. Ting of the Massachusetts Institute of been called the “November Revolution” in Technology jointly announced their indepen- high-energy physics. How did the discovery dent discoveries of the J/ψ meson, a particle change physics, and how do you feel about whose existence was proscribed under the your role as a so-called revolutionary? then-Standard Model of particle physics. Richter: Most advances in science are in- The discovery, known to the physics com- cremental. Very few are really revolutionary, munity as the “November Revolution,” andthisonewasonethatwastrulyrevolu- earned Richter and Ting the 1976 Nobel tionary because this particle was not allowed Prize in physics and led to the emergence to exist by the Standard Model of how the of a revised Standard Model. Richter sees elementary particles were made up from this landmark work as only one part of the then-known substructure. So we were, a career that has also included 15 years in fact, a group of revolutionaries. There are as SLAC laboratory director and 15 years 35 names on the paper, including all of the as a commentator on United States energy graduate students. “November Revolution” Burton Richter. Image courtesy of United policy. In October 2014 Richter, a member was the name the high-energy physics com- States Department of Energy. of the National Academy of Sciences, was munity applied to the simultaneous discov- awarded the National Medal of Science, ery: two places, two different experiments. to derive everything. Well, we are not honoring all three facets of his career. To This wasn’t a case where you had to wait there yet. commemorate the honor, PNAS spoke with for confirmation. So it changed particle phys- PNAS: In the last third of your career, you Richter. icsinaveryfundamentalwayandsetusin have been speaking and writing about United PNAS: You and Samuel C. C. Ting inde- a new direction with a new version of what States energy policy. Why do you feel strongly pendently discovered the same subatomic par- ’ has been called the Standard Model. That s about energy? ticle at about the same time. How did you and very satisfying. Richter: ’ PNAS: The energy issue is actually much Dr. Ting learn of each other sdiscovery? How far has particle physics come broader than the one that’s usually discussed. Richter: SLAC always has had an external since then? Richter: Most of the shouting today is about climate program advisory committee. People submit Therevolutionsetthestagefor change, which is certainly very important, proposals to use the accelerators and a com- the current Standard Model, which I charac- but energy is also vital to the economic de- mittee advises the director on which to ac- terize as a beautiful book with a bunch of velopment of nations, and since most of the cept. Sam was a member of that committee. Post-it notes stuck on various pages. And world is poor, much more energy is needed if ’ The famous weekend actually preceded the those Post-it notes are things we don t yet thosepooraregoingtoclimbtheeconomic ’ scheduled Monday meeting of the program understand. Here sanexample:neutrinos ladder. Also, a secure energy supply is neces- committee. So Sam arrived on Sunday. The are now known to have small masses. The sary for national security. So if you take that whole world was already buzzing, although Standard Model neither explains it nor for- perspective, our ways simply have to change ’ ’ ’ we hadn t even written a paper yet, with bids it, but it s a surprise and we still don t for a lot more reasons than climate change. ’ ’ the news of narrow resonance, which wasn t understand why. There s five times as much Look at oil, for example. Right now we pump allowed by the then-Standard Model, and dark matter in the universe as there is the 90 million barrels a day. That’swhatthe ’ Sam must have heard about this as soon as kind of matter we re composed of, and we world uses. Most projections say that if noth- he landed. On Monday morning [SLAC di- don’t know anything about it at all. We don’t ing interferes, economies are going to grow rector Wolfgang] Panofsky had us both into know what it is, we don’tknowhowheavyit by about a factor of four by the end of the his office where we talked about what each of is, we only know that it had very weak kind century, and most of that is going to be in the us had done. It was very clear to both of us, of interactions, and gravity, and it’swhat developing world. Well, 360 million barrels instantly, that this was the same thing, dis- holds our galaxy together. The Standard of oil a day? No way can we do anything like covered in two entirely different reactions at Model has nothing to say about it. It doesn’t that anything near the current price, and it two entirely different laboratories 3,000 miles saythatitmustexist.Itdoesn’tsaythatit may be that there isn’t even enough to do it apart. We scheduled a joint seminar that af- can’texist.Itsays“Okay, that’ssomething even with the current price. ternoon. And that’sthewayitwas.Ithink else.” I always hoped that high-energy physics I usually remind people, when I talk this both of us realized we had to get the papers would end up with one equation and one way, that my granddaughters, aged 10 and 7, ready pretty fast. We sent a courier off on constant, and from that we would be able are the ones that will feel the effects of the

3852–3853 | PNAS | March 31, 2015 | vol. 112 | no. 13 www.pnas.org/cgi/doi/10.1073/pnas.1503536112 Downloaded by guest on September 29, 2021 QNAS problem, but they’re too young to do any- things in the world of efficiency actually save who wouldn’t pay a lot of attention to thing about it, and it’s simply unconscionable money. I’m going to do my bit. I’m83years “Richter the scientist.” So I do what I can. to leave this problem to a bunch of 7-year- old. I can just keep pushing people. Nobel

“ + − olds and 10-year-olds. Many things that we Prizes are great door openers. Richter the 1 Agustin J-E, et al. (1974) Discovery of a narrow resonance in e e can do have little or even negative cost. Some Nobel Prize winner” cangotalktopeople annihilation. Phys Rev Lett 33(23):1406–1408.

Gabrielsen PNAS | March 31, 2015 | vol. 112 | no. 13 | 3853 Downloaded by guest on September 29, 2021