Feb 20, 2013
The missing life of DORIS
The article "The three lives of DORIS" (CERN Courier December 2012 p22) briefly summarizes the history of DORIS. We believe the author has forgotten one "life", in the years 1977–1978, when DORIS was upgraded from 3.5 GeV to 10.0 GeV in the centre of mass. Though being only a short life it is worth mentioning for at least three reasons.
First, it enabled a scan of the full range of energies and confirmed that there were no new quarks (below the Y) and strengthened knowledge of the properties of jets from the hadronization of quarks. Second, it allowed the detection of the new Y resonance at 9.46 GeV, which decays mainly strongly and is very narrow, and thereby delivered the necessary confirmation of the new b quark found a year earlier at Fermilab via the Y resonance at 9.5 GeV. Third, through the analysis of the hadronic decays of the Y, it provided first evidence for the decay Y → 3 gluons → 3 jets, for gluon jets and for the spin 1 of the gluon, and hence made an important contribution to the discovery of the gluon, confirming the expectations of QCD.
The reason for forgetting this "life" could be that the author based his article on a book published in 2009, and so missed two more recent papers. In one we put new light on the importance of the PLUTO experiment at DORIS in 1978 in contributing to the discovery of the gluon (Stella and Meyer 2011). The second is an independent review where this new perspective is mainly confirmed (Ali and Kramer 2011, see e.g. p3 and pp20–24 in chapter 4, "Gluon jets in Y decays").
For completeness, we would like to remember not only the results of PLUTO at DORIS but also other "forgotten" experiments: DASP, Crystal Ball, DASPII, DESY-HDD and LENA.
A Ali and G Kramer 2011 Eur. Phys. J. H 36 203.
B Stella and H-J Meyer 2011 Eur. Phys. J. H 36 243.