I thoroughly enjoyed reading Konrad Kleinknecht’s excellent summary of Jack Steinberger’s life and physics career (Physics Today, September 2021, page 59). I was unaware of several of Steinberger’s achievements. In my opinion, he deserved additional Nobel Prizes for some of them, such as his calculation of the two-photon decay rate and lifetime of the neutral pion and discovery of KL0 leptonic decay’s CP-violating charge asymmetry.

I would like to point out, however, that the Weinberg angle, θW, referred to in the obituary is also called the “weak mixing angle.” It was invented by Sheldon Glashow in his famous 1961 paper, “Partial-symmetries of weak interactions.” It is the angle that diagonalizes the 2 × 2 matrix of the neutral gauge bosons, giving the Z boson and the photon as the mass eigenstates in the model based on the gauge group SU(2) × U(1). With that model, Glashow proposed to unify electromagnetic and weak gauge interactions.

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