Limits on extra dimensions
We enjoyed the informative article Testing times for strings by Ignatios Antioniadis in the July/August 2003 edition of CERN Courier. The author gave a most accessible report on string theory and associated hidden dimensions. We would like to remedy one apparent oversight in the article regarding the status of current experimental searches for extra dimensions. Such searches are already an ongoing and active part of the physics programme at the Fermilab Tevatron. Both the CDF and D0 collaborations have performed searches sensitive to the anomalous production of dilepton and diphoton final states associated with graviton interactions in extra dimensions.
At the Lepton-Photon Conference at Fermilab in August, the D0 collaboration announced the most stringent limit so far on the scale of large extra dimensions, based on 250 pb-1 of data from Tevatron Runs I and II combined. The new limit on the fundamental Planck scale is 1.37 TeV (in the GRW convention). We expect to significantly improve on this sensitivity as more data are collected at the Tevatron.
John Womersley and Jerry Blazey, co-spokespersons, D0 experiment at Fermilab.
Bubble-chamber pioneers
The July/August 2003 issue of CERN Courier contains an article entitled The legacy of the bubble chamber. It is regrettable that the article does not acknowledge the monumental work of Ralph Shutt's bubble-chamber group at Brookhaven National Laboratory. Not only was this group technically and scientifically creative, but they also initiated the social experiment of providing film to outside groups for analysis at their own institutions.
R Ronald Rau (retired), Brookhaven National Laboratory.
New products
PI (Physik Instrumente) has announced the arrival of the world's smallest multi-axis, closed-loop, piezoelectric scanning stages for applications in scanning microscopy and nano-manipulation. The stages offer high multi-axis linearity and stability, and are capable of 50 picometres resolution. For further information, e-mail: info@polytecpi.com, or visit the websites: www.pi.ws or www.polytecpi.com.
SPSS Science is now offering an all-inclusive bundle of software for data analysis and graphic presentation. The two components of the new software bundle consist of SigmaStat, which contains the most frequently used statistical procedures, and SigmaPlot, which includes editing functions that enable the creation of publication-quality graphs. For further information about the bundle, see the SPSS website at www.spss.com/science.