Book Description

A new type of detector capable of reaching very small angles was successfully used in Fermilab E811 in Jan. 1996. It consists of a bundle of 15,000 scintillating fibers each of 100[micro]m diameter. The fibers are oriented parallel to the beam and gave a measuring resolution of 38[micro]m transverse to the beam. In this report the authors analyzed about 50,000 elastics as close as 3 mm from the beam. Simulated data runs show that the total cross section should be obtained to an accuracy of[+-]2%. The smallest t-bin used has a background subtraction of[approximately]20%, but for most of the t-bins the background is much smaller and the detection efficiency is over 95%. Very preliminary analysis gives a total cross section of[approximately]71 mb at[radical]s= 1.8 TeV using a luminosity-independent method. This is consistent with the earlier Fermilab E710 result which used a different kind of elastic detector. The rho-value analysis has not yet been completed. A personal interpretation (by Orear) of a slower rise in the total cross section is given at the end.