A Search for Exotic S=-2 Baryons Decaying to Xi pi

This summarizes an analysis which searches for the rare exotic five quark baryons, pentaquark, decaying to Xi pi. These results were blessed at the B Physics Meeting 19-Feb-2004 and correspond to a dataset of 220 pb-1.

Motivation

Manifestly exotic baryons decayin to Xi- pi- and Xi- pi+ were recently claimed by NA49 Experiment. Traditional 3-quark baryons cannot not decay to Xi- pi-. A signal in Xi- pi- invariant mass could be explained as 5-quark baryon state comprised of (dsd\bar{u}d) quarks, Xi- pi+, then is it's isospin partner. At CDF we have developed standalone silicon tracking of long lived Xi hyperons that allows to achive dramatic background reduction and improved momentum and impact parameter resolution. We have used clean sample of Xi hyperons to search for exotic states decaying to Xi pi

Description

A complete description of the analysis is available here: html, ps.

Figures

Below the eps versions of all figures available for downloads.

Figure 1 : anti-decouplet of pentaquarks
Figure 2 : Xi signal in TTT requiring SVX hits for Xi tracks
Figure 3 : invariant mass spectrum of Xi,pi
Figure 4 : invariant mass spectrum of Xi, pi+ and Xi, pi- combinatins
Figure 5 : Xi pi+ mass spectrum
Figure 6 : Xi pi- mass spectrum
Figure 7 : pT spectrum of pentaquark canduidates in TTT data
Figure 8 : eta spectrum of pentaquark canduidates in TTT data
Figure 9 : Xi signal in JET20 data requiring SVX hits for Xi tracks
Figure 10 : invariant mass spectrum of Xi,pi in JET20 data
Figure 11 : invariant mass spectrum of Xi, pi+ and Xi, pi- combinatins in JET20 data
Figure 12 : Xi pi+ mass spectrum in JET20 data
Figure 13 : Xi pi- mass spectrum in JET20 data

Documentation

A full description of the analysis is in cdfnote 6855

description of Xi tracking in silicon: cdfnote 6527

The pre-blessing talk at the B Physics meeting, and blessing talk offer a summary of the analysis.