Superparticles on the energy horizon

In his article “Is String Theory Phe-nomenologically Viable?” (Physics Today, June 2006, page 54 ), Jim Gates extrapolates from past discoveries to estimate the time of discovery of new massive elementary particles such as those predicted by supersymmetry. He uses the discovery dates and measured masses of the neutron and the W boson, and proposes that “one can crudely estimate the rate at which humanity is progressing in its ability to detect massive particles: about 1.5 GeV/c ² per year. Thus, if Nature is kind enough to provide light superpartners, one might still expect about a century to pass before a superparticle is directly observed.”

A more appropriate extrapolation would be from the discovery of the bottom quark (mc ² ≃ 4.5 GeV) in 1977 to the 1995 discovery of the top quark (mc ² ≃ 175 GeV), a rate of approximately 10 GeV per year. Given that 10 years have passed since the top discovery, using these two points to extrapolate might lead Gates to conclude that we’re already overdue for another discovery.

Neither of these extrapolations is relevant, however. The timing of discoveries at accelerators will be determined by investment in facilities such as the Tevatron, the Large Hadron Collider, and the International Linear Collider, and in talented people who work on the machines and detectors and who analyze the data, including theorists who develop the techniques and tools necessary to compare the data to standard model predictions. I hope these efforts have Gates’s full support and that of the string theory community.