May 10, 2000

TO:  Christopher Wesselborg
     Associate Editor
     Physical Review C

RE:  Resubmission of Phys. Rev. C Manuscript CJ7154

Dear Dr. Wesselborg:

Included in this email is the LaTeX file for revised manuscript CJ7154,
"Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?," by
S. D. Paganis, et al. which we wish to have reconsidered for publication as
a regular article in The Physical Review C.  The paper contains 5 figures,
the first three of which are not changed.  Figures 4 and 5 are new and replace
the original figures 4 and 5.  The new figures 4 and 5 are being sent in
postscript format via separate emails.

We wish to thank the referee for his or her very thoughtful criticisms and
recommendations for this manuscript.  We have incorporated all the recommendations
of the referee in the revised manuscript.  In addition we have added several
recent and very relevant references that have appeared since our original
submission.  In the following we respond to each of the referee's points
in the order listed in the referee's report and explain the resulting
changes in the paper.

(1)  The phrase "...window of opportunity..." in the abstract was replaced
     with the sentence, "Results indicate that such resonances may be
     discovered using STAR..."

(2)  The first sentence of the Introduction was rewritten as requested.

(3)  The sentence with the phrase "One can speculate..." was rewritten as
     "It may be that the Lambda Lambda invariant mass spectrum..."

(4)  "Ultrarelativistic" was removed throughout the paper and replaced with
     "relativistic."

(5)  The statement in the first paragraph of Section 4 that vertex tracking
     is "required" was softened to say that it is "needed."  We agree that
     vertex tracking is not generally required in order to reconstruct
     cascade(-) or Lambdas, as for example in fixed target experiments. 
     However, in the context of the RHIC collider experiments, which is 
     the focus of our paper, vertex tracking is very
     important for reducing the amount of false cascades.

(6) and (8) -- The original version of the paper was admittedly too vague with
     respect to the statistical requirements for the proposed dibaryon search.
     The referee's main point is that a statistically meaningful quantity
     such as the ratio of signal to signal error, or number of sigmas of the
     signal, should be computed and reported.  We agree completely and have
     therefore extensively rewritten Sec. 4, both the analytical part and
     the numerical simulation results and discussion.  New simulations were
     carried out (see also points 7 and 9 below) and the results are now
     reported as signal to signal error ratios (i.e. number of sigmas). 

     In addition to the revised Sec. 4, the new results are also reported in
     a new Table IV, new Fig.5, and a new example mass spectrum in Fig. 4.  Also
     the closing paragraph in the Summary and Conclusions was rewritten.

     With these new results the reader can better understand how the statistical
     significance of the dibaryon resonance signal depends on the assumed
     production rate, resonance width and number of collision events.
     We use the numerical results along with the analytical results in Sec. 4.1
     to estimate the required number of Au+Au central events (with an assumed
     multiplicity) to achieve a specified statistical signal as a function
     of dibaryon resonance production rate and width.

(7)  The assumed mass distribution model for the resonances was changed from 
     Gaussian to that predicted by the P-matrix total cross section for
     proton + cascade(-) scattering.  This was obtained from Eqs. (3)-(6) in
     the paper but without the nonresonant amplitude
     [a1 was set to 0 in Eqs.(5) and (6)] and with the incident flux factor
     in the definition of total cross section removed.  The P-matrix
     resonant amplitude is approximately Breit-Wigner but modified for
     threshold effects [see Eqs. (57) and (58) in Ref.9].  The H^{27}
     mass distributions now have the correct behavior at threshold, at
     least in the context of the P-matrix resonant scattering model.

(9)  For uniform proton and cascade(-) distributions in momentum space the
     random, combinatoric proton + cascade(-) invariant mass distribution
     at threshold is proportional to sqrt(M - M_thresh), where M is the
     proton + cascade(-) invariant mass.  We therefore constrained the
     analytical model for the background to have this sqrt(M - M_thresh) 
     dependence near threshold.  Excellent fits to the proton + cascade(-)
     backgounds were obtained for each case as shown in the new example
     spectrum in Fig. 4 by the solid line.

Additional changes to the manuscript:
------------------------------------

We added the following references indicated by their numbers in the paper:

    #3,4  - recent reviews of dibaryon searches
    #10   - new lattice QCD calculations which suggest that H0 is unbound
    #15   - recent coalescence model estimates for H formation
    #17   - new data from KEK showing an enhancement in the low mass
            region of the Lambda-Lambda spectrum.
    #21   - additional reference for STAR SSD capabilities
    #27   - textbook level explanation of threshold-cusp enhancements in
            cross sections due to coupled-channels effects.
    #29   - supplementary note which clarifies a step in Sec. 4.1.

We appreciate the comments of the referee and believe that this process has
resulted in a much improved manuscript that we believe is now suitable for
publication in Physical Review C.

Sincerely,

Lanny Ray
Dept. of Physics
RLM 5.208
The University of Texas at Austin
Austin, Texas 78712

email:  ray@physics.utexas.edu
Fax:    (512) 471-9637
Office: (512) 471-6107