Research-TPP

A la recherche de TPP

Sometime in the summer of 1964, the Civil Rights summer in the USA,  I received a preprint request card from one "Roger Blin-Stoyle"of the "School of Mathematical and Physical Sciences, University of Sussex, Falmer, Brighton. (In those days, long before the advent of the internet or the arXiv, papers were typed by secretaries on to "onion skins, one for each page. These were then wrapped around an ink drum and typically one to two hundred copies of each page were printed. After collation, usually by press-ganged graduate students, the preprints were posted to the main groups around the world and to selected individuals whom the author adjudged might have a particular interest in the topic.) That was my first contact with Roger; I thought what a funny name he had and wondered about its origin. I'd never previously heard of the University of Sussex. The following year I was a postdoc in Oxford and by then the new University of Sussex was infamous if not famous: the social antics of the Jay twins, the daughters of the Labour Government's  minister Douglas Jay, and their contemporaries meant that the University was often featured by the tabloid press, and deplored by the Daily Telegraph.With such credentials, clearly the place couldn't be all bad, so I had little hesitation in applying for one when I read an advertisement in The Guardian  for "Lectureships in Theoretical Physics" at Sussex; in any case, I needed a job.  There was no M25 in those days so the drive to Brighton for my interview was lengthy, but enjoyable; I was impressed to be given overnight accommodation in The Old Ship  hotel on the seafront which was, I was later assured by Gabriel Barton, if not the best, certainly the most distinguished  hotel in Brighton. The interview was conducted by Roger (apparently perfectly normal, notwithstanding the name), Ken Smith and Gabriel; the latter gave me a walking tour of the campus and the teacher training college (now Brighton University Falmer campus) then under construction on the other side of the railway tracks. A month or two after I had accepted the job offer, in the summer of 1965, I received a letter from Roger informing me that they had admitted a research student for me to supervise, a Miss Anjali Medhi, recently graduated from Imperial College's DIC programme. For these reasons, I have observed that Roger organised my whole life! He gave me my first permanent job and arranged my introduction to  the woman who later became my wife. In Oxford, Lady Peierls, the wife of Prof Peierls,  then Head of the Department of Theoretical Physics, was often ascribed similar powers, even telling young faculty members which house they should buy. Roger never did that, but he did volunteer to be the godfather of our first child, an offer that I now regret that we declined; I assumed that he was religious, and it was only many years later, at his humanist funeral in 2007, that I discovered he was not.

As Dean of MAPS, Roger had a nice office in Physics I, now Pevensey I  2C1 and currently used as a seminar room. There were then three of us who regarded ourselves as particle theorists: Gabriel, Norman Dombey and me. (We didn't use the abbreviation "TPP" in those days.)   We had offices in the "Terrapin, a prefabricated temporary building situated alongside the service road, now called the North-South Road, and overlooking what is now Sussex House. The windows were totally opaque due to the mud thrown up by the interminable stream of construction traffic.  There was little insulation, so we were freezing in winter and frying in summer; one could easily hear conversations, or worse, in the adjacent offices.
 
Roger regarded himself more as a nuclear theorist  interested in the manifestation of particle physics effects in nuclei, rather than a particle theorist. He was interested in things like the charge dependence of nuclear forces, and meson exchange effects. The observation by Madame Wu in 1956 of parity violation in the beta decays of polarised cobalt nuclei led to the reformulation in 1958 by Feynman and Gell-Mann of Fermi's 1934 current-current theory of the weak interactions. In the modern version,  the leptonic and hadronic (charged) weak currents both had vector and axial vector pieces; the vector and axial vector  components of the weak nucleon current lead respectively to Fermi and Gamow-Teller beta decay transitions. Further, the purely hadronic (weak) Hamiltonian is also parity-violating. Since the strong part of the Hamiltonian is parity-conserving, it follows that the nuclear eigenstates have small admixtures of the "wrong paritycomponents. This in turn means that transitions that would otherwise be forbidden may actually occur but at a much slower rate than the allowed transitions. Roger was particularly active in persuading the experimentalists, Dennis Hamilton and Jim Byrne, to devise experiments to study these transitions. The discovery by Fitch and Cronin in 1964 of CP-violation (charge-conjugation C times parity reversal P) in the (weak) neutral kaon decays was strong evidence, later confirmed, of T-violation, i.e.violation of time-reversal T-symmetry, although the precise origin of the interaction responsible was not (and is still not) known.  If it is in the weak interactions, then, as for parity, the nuclear eigenstates have (presumably small) admixtures of the "wrong T-parity. So later on, Roger was again active in urging experimental searches for T-violation in nuclear transitions. I particularly recall the arrival in 1968 of Roger's student Peter Herczeg, a dear friend,  now retired from the Theory Division at Los Alamos National Laboratory. Peter  fled Czechoslovakia during the Prague Spring in which the Soviet army invaded the country to halt reforms introduced by Alexander Dubcek. Peter worked on the effects of "irregular" components of the weak hadronic current, i.e.  components having the "wrong  or opposite G-parity to the standard components in the Feynman and Gell-Mann theory. One day, at tea on the Bridge, now the Bridge Cafe, I joined Peter talking to Gabriel. While waiting to ascertain the topic of their discussion, I realised that they were conversing in a foreign tongue, Hungarian, in fact. Until that day, I had had no inkling that Gabriel was anything other than an archetypal English gentleman -  tweed sports jacket, woolen tie, Westminster and Christ Church: you can't get much more English establishment than that -  nor of his flight from the Nazis in Budapest.