Search for Strangeonium Hybrids


Contact person - S. U. Chung
516-344-3885
suchung@bnlarm.bnl.gov


The E852 Collaboration is currently in the process of carrying out a systematic search for gluonic mesons produced in interactions at 18 GeV/c. This effort, along with others extant in the U.S., in Europe and in Japan, is expected to yield a more complete picture of the role of valence gluons as constituents in hadrons. However, all these experiments concentrate on the final states produced by an initial system containing only light, non-strange quarks. A scan of the Review of Particle Properties reveals that very little is known about the gluonic strangeonia (ss + g).

Recently, F. Close and P. Page have extended the flux-tube model of hadrons to the strangeonium sector with gluonic excitations having both exotic and non-exotic quantum numbers. Their predicted masses range from 2.15 to 2.25 GeV, with the widths ranging from 120 to 575 MeV. In particular, they predict a narrow (width 120 MeV) non-exotic gluonic strangeonium at mass 2.15 GeV with the quantum numbers coupling to and . It would be exciting indeed to find such a narrow object.

A systematic search for these gluonic strangeonia (ss + g) will require a separated K beam interacting with a nucleon. For this we require an RF separated beam and assume that such a beamline is set up leading to the BNL Multi-Particle Spectrometer (MPS). With an upgraded AGS, one can reasonably take protons or 25 tera protons (TP) on the primary target leading to the MPS, and this is expected to yield a flux of per spill for a K beam at 12 GeV/c. If one assumes a live K beam of per spill (corrected for the deadtime) on a 60-cm LH target and a running time of 5,000 AGS hours at 1,000 spills per hour, then one can achieve a visible sensitivity of 330 events/nbarn, assuming an overall acceptance of 10%. For comparison, one may recall that the LASS experiment at SLAC ( interactions at 11 GeV/c) had a sensitivity of 4.1 events/nbarn.