Blackett's photos will come out in P.R.S.

It is that they have capitulated on the question of positive electrons and agree with Anderson that there are present in large numbers among the tertiary or quartinary (or whatever they are) ionizing particles seen in a Wilson photograph of the cosmic ray effects particles of positive charge and electronic mass.I take it that Blackett has collected so many photographs of such tracks as those earlier ones of Anderson that he can no longer resist this devastatingly interesting conclusion. I have just received a letter from Rutherford which contains some of Blackett's work which may interest you and Anderson.

Nicola Cabibbo, 'Weak Interactions,' Enrico Fermi: His Work and Legacy (2001) ed., Carlo Bernardini, Luisa Bonolis.

The study of weak interactions has led to surprising discoveries, among which the violation of specular symmetry (known as parity symmetry or P symmetry), and the violation of time reversal symmetry ( T symmetry) and of the symmetry between matter and antimatter ( CP symmetry). Many new manifestations of weak interactions, which could be interpreted using Fermi's 1933 theory, were found in the following decades.

In his theory of beta reactivity Fermi introduced a new type of interactions among elementary particles, which today we call ' weak interactions'.

Carl David Anderson, 'The Apparent Existence of Easily Deflectable Positives' (1932) Science Vol.

The specific-ionization is close to that for an electron of the same curvature, hence indicating a positively-charged particle comparable in mass and magnitude of charge with an electron. Protons or heavier nuclei of the observed curvatures could not have ranges as great as those observed.

The interpretation of these tracks as due to protons, or other heavier nuclei, is ruled out on the basis of range and curvature.

1.15 The Mystery of the Missing Antimatter (2010).

1.13 Meeting the Demands of Reason (2009).

1.12 Neutrino Models and Leptogenesis (Dec 2008).

1.11 The Matter-Antimatter Asymmetry of the Universe (2002).

1.10 Antimatter: The Ultimate Mirror (2000).

1.9 The Autobiography of Carl David Anderson (1999).

1.8 Mirror Matter: Pioneering Antimatter Physics (1988).

1.7 The Concept of Particle Creation before and after Quantum Mechanics (1976).

1.6 'The Golden Age of Theoretical Physics' (1972).

1.5 Violation of CP invariance, C asymmetry, and Baryon asymmetry of the Universe (Sept 23, 1966).

1.3 Theory of Electrons and Positrons (Dec 12, 1933).

1.2 The Positive Electron (Feb 28, 1933).

1.1 The Quantum Theory of the Electron (Jan 2, 1928).

The baryon asymmetry of matter and antimatter in the observable universe, to include hypothesized baryogenesis, is one of the great unsolved problems in physics. Theory allows anti-atoms corresponding to the known chemical elements. The most complex, artificially produced anti-nuclei is antihelium. Man has bound together a tiny fraction of produced antimatter particles to form antimatter atoms, e.g., a positron and an antiproton to form an atom of antihydrogen.

The majority of this annihilation energy is ionizing radiation. Interaction between any particle and its anti-particle leads to mutual annihilation, with the emission of gamma rays, neutrinos, and sometimes less-massive particles and their respective antiparticles. Theoretically, a particle and its anti-particle have the same mass, but opposite electric charge, and other differences in quantum numbers. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling. Antiparticles are generated in particle accelerators (total production of which is a few nanograms), in natural cosmic ray collisions and in some radioactive decay. Antimatter is composed of antiparticle 'partners' of corresponding 'ordinary' matter particles.

Antimatter picture