Inelastic Sum Rules

The history and present status of several sum rules for deep-inelastic lepton scattering are reviewed, with particular attention to the discovery of scaling, partons, quarks and QCD. Two outstanding issues are then discussed in more detail: the singlet (Ellis-Jaffe) nucleon spin sum rule and the Drell-Hearn-Gerasimov-Iddings sum rule. 1 Introduction It is a great pleasure to be here today to honour Sid Drell, and a great honour for me to have been invited to speak. I first heard of Sid in October 1964 when, as a beginning 21-year-old graduate student, I went to see my supervisor Dick Dalitz for the first time. Dick told me that he would like me to learn to calculate as quickly as possible, adding 'There is a new book by Bjorken and Drell: I have not seen it yet myself, but those characters would write a good book'. He was absolutely right, and it was my bible for many years to come. I first met Sid in September 1970 when I arrived here from CERN as a postdoc. I had the office next to his (which is the office occupied today by David Leith). Sid operated an open-door policy, and everyone was allowed to gather in his office, attracted by his loud voice, and participate in any discussion that happened to be going on. All of us postdocs and students learned a great deal of physics from those discussions, and we were also able to participate vicariously in the non-secret parts of Sid's Washington life. Towards the end of my two years at SLAC, Sid went away for a short sabbatical and he and Harriet kindly allowed us to move into their house. This experience gave me a lot of insight into the Drell family and into their three characteristically named cats — Harvard, Princeton and Yale. Subsequently, our paths crossed many times, for example when Sid came on sabbatical to Oxford. Most recently our world lines became intertangled through the HEPAP Panel (the so-called Drell Panel) that Sid chaired in 1994, which helped start what I hope is the dawn of a new age of global collaboration in particle physics. On behalf of all those who are involved with the LHC, in over 40 countries including the 19 Member States and the USA, I would like to take this opportunity to thank Sid for the statesman-like report that his Panel produced. The first part …