The wikipedia page on pair production has an answer to Hotson`s question: https://en.wikipedia.org/wiki/Pair_production
<<For photons with high photon energy (MeV scale and higher), pair production is the dominant mode of photon interaction with matter. These interactions were first observed in Patrick Blackett's counter-controlled cloud chamber, leading to the 1948 Nobel Prize in Physics.[3] If the photon is near an atomic nucleus, the energy of a photon can be converted into an electron–positron pair: γ → e− + e+ The photon's energy is converted to particle mass in accordance with Einstein’s equation, E = m ⋅ c2; where E is energy, m is mass and c is the speed of light. The photon must have higher energy than the sum of the rest mass energies of an electron and positron (2 ⋅ 511 keV = 1.022 MeV, resulting in a photon-wavelength of 1.2132 picometer) for the production to occur. The photon must be near a nucleus in order to satisfy conservation of momentum, as an electron–positron pair produced in free space cannot both satisfy conservation of energy and momentum.[4] Because of this, when pair production occurs, the atomic nucleus receives some recoil. The reverse of this process is electron positron annihilation.>> Harry On Fri, Sep 25, 2020 at 1:27 PM Terry Blanton <[email protected]> wrote: > > > On Fri, Sep 25, 2020 at 1:18 PM Terry Blanton <[email protected]> wrote: > >> >> >> On Fri, Sep 25, 2020 at 1:07 PM JonesBeene <[email protected]> wrote: >> >>> If one is a follower of Don Hotson >>> >> >> If one wants to be, >> > > And for those who do not, let me see if this sidebar from the first paper > can change your mind. > > The Hotson “family business” is English literature. Mr. Hotson’s > father and uncle had Harvard Ph.D.s in the subject, and his late > uncle was a famous Shakespeare scholar. Mr. Hotson, however, > always intended a career in physics. Unfortunately, he could not > resist asking awkward questions. His professors taught that conservation > of mass-energy is the never-violated, rock-solid foundation of all physics. > In “pair production” a photon of at least 1.022 > MeV “creates” an electron-positron pair, each with 0.511 MeV of > rest energy, with any excess being the momentum of the “created” pair. So > supposedly the conservation books balance. > But the “created” electron and positron both have spin (angular momentum) > energy of h/4π. By any assumption as to the size > of electron or positron, this is far more energy than that supplied > by the photon at “creation.” > “Isn’t angular momentum energy?” he asked a professor. > “Of course it is. This half-integer spin angular momentum is > the energy needed by the electron to set up a stable standing wave > around the proton. Thus it is responsible for the Pauli exclusion > principle, hence for the extension and stability of all matter. You > could say it is the sole cause of the periodic table of elements.” > “Then where does all this energy come from? How can the ‘created’ > electron have something like sixteen times more energy than > the photon that supposedly ‘created’ it? Isn’t this a huge violation of > your never-violated rock-solid foundation of all physics?” > “We regard spin angular momentum as an ‘inherent property’ > of electron and positron, not as a violation of conservation.” > “But if it’s real energy, where does it come from? Does the > Energy Fairy step in and proclaim a miracle every time ‘creation’ > is invoked, billions of times a second? How does this fit your > never-violated conservation?” > “‘Inherent property’ means we don’t talk about it, and you > won’t either if you want to pass this course.” > Well, this answer sounded to him like the Stephen Leacock > aphorism: “‘Shut up,’ he explained.” Later Mr. Hotson was taken > aside and told that his “attitude” was disrupting the class, and > that further, with his “attitude,” there was no chance in hell of his > completing a graduate program in physics, so “save your money.” > He ended up at the Sorbonne studying French literature, and later > became a professional land surveyor. > However, he has retained a lifelong interest in the “awkward > questions” of physics, and with Dirac’s Equation has found > some answers > > <end> > > I hope he had the last laugh. >
