Observation of Antiprotons in Physical Review 100 Issue 3 pp. 947-950, November 1, 1955; WITH Antiproton Star Observed in Emulsion Physical Review 101 pp. 909, January 15, 1956

New York: The American Physical Society. 1st Edition. 1956 FIRST EDITION IN ORIGINAL WRAPS of the two papers that won Chamberlain and Segre the 1959 Nobel Prize for the first experimental confirmation of the antiproton, a new subatomic particle identical in every way to the proton, except that its electrical charge was negative instead of positive.

Chamberlain and Segre's discovery was the culmination of a hunt whose origins go back to 1928, when British physicist Paul Dirac formulated a theory to describe the behavior of relativistic electrons in electric and magnetic fields. Dirac's equation was unique for its time because it took into consideration both Einstein's special theory of relativity and the effects of quantum physics, as proposed by Erwin Schrödinger and Werner Heisenberg, to describe the behavior of slow-moving particles. While the math worked, few physicists gave Dirac's equation much serious consideration, because it allowed particles of negative energy. From the standpoint of both physics and common sense, the energy of a particle could only be positive (Yarris, "The Golden Anniversary", Science at Berkeley Lab, 2005).

A number of physicists attempted to find the antiproton, but Chamberlin and Segre were particularly clever. According to Segre, "I decided to attack the problem in two ways. One was based on the determination of the charge and mass of the particle. The other concentrated on the observation of the phenomena attendant on the annihilation of a stopping antiproton. The stopping antiproton and a proton of the target should mutually annihilate each other, and the rest mass of the two particles should transform itself in one of many possible ways into other particles such as pions. These would leave tracks in a photographic emulsion and the annihilation would thus become evident. . .

"We started the run on August 25, 1955, and after a few days of tuning up, we began observing antiproton signals. We based the identification on measurement of the velocity, momentum, and charge of a particle. The signals for velocity were oscilloscope traces recording the passage of a particle through a velocity-selecting Cerenkov detector. . . . We detected about one antiproton for every few hundred thousand other particles crossing our apparatus. . . . We decided to write a letter to the Physical Review and an article for Nature. . . . The mass-spectrograph experiment concluded on October 1, 1955, having proved the existence of the antiproton, and soon thereafter the emulsion work confirmed it" (Segrè, A Mind Always in Motion, pp. 256-57).

"The antiproton also became a workhorse of experimental particle physics, as scientists [ at CERN, Fermilab, etc.] later spent decades smashing it into protons in racetrack-shaped accelerators and measuring the sprays of weird new particles that emerged, producing what seemed to be an endless stream of Nobel Prizes" (New York Times Obituary, March 2, 2006). According to physics Nobelist Stephen Weinberg: "If it had not been discovered, the foundations of physics really would have crumbled," Dr. Weinberg said. He added that the antiproton "was something like the South Pole: it's something that you know is there but you just have to get there anyway" (ibid). CONDITION & DETAILS: New York: The American Physical Society. "Observation of Antiprotons" in Physical Review 100 Issue 3 pp. 947-950, November 1, 1955; WITH "Antiproton Star Observed in Emulsion" Physical Review 101 pp. 909, January 15, 1956. Very light scuff to the front wrap of 101. Otherwise both issues are in near fine condition.