S. Chapman, J.R. Nix, and U. Heinz, Phys. Rev. C52:2694 (1995)

Extracting source parameters from Gaussian fits to two-particle correlations

Introduction

• Discuss source vs. correlation K-dependent components

  Approximation	Source	Correlation
  Saddle-pt.	10	6
  Azimuthal Sym.	7	4
  Kt below T/Beta*Beta	4	4

Lorentz covariant C2

• Develop formalism for Saddle-Pt. Appprox.
• They note that non-gaussian sources produce C2's that look gaussians with similar rms --- Where have I heard that one before?

Azimuthally symmetric sources

• q2 perp. to B_T implies B2u=Bu2=0
• R1**2-R2**2= emission time if no x-z,x-t-z-t correlations
• Add q_T term to YK to get Generalized Yano-Koonin (GYK)

The measurement frame (3+1-examples)

• Static gaussian - standard interpretations apply
• Boost-invariant - Rz has T/mT (t0/cosh(Y))**2 term in fixed frame fit
  T/mT t0**2 term in LCSM fit
• Boost-invariant w/ non-invariant cut-off - more complex forms, used to advocate GYK
• A class of models - symmetries expressed in curvature tensor (B), B30 vanishes for GYK fit

Trasverse expansion

• Go to last example (non-invariant cut-off), add in v_T term of v*r/R
• Use to show that low-kT approx means Ek .lt. T/Beta**2
• Leads to mT dependence of sqrt(1+mT*Beta**2/T cosh(eta-Y))

Figures

• none

References

Saddle Pt. Approx.
• Y.M.Sinyukov, Hot Hadronic MAtter: Theory and Experiment, ed. Letessier and others, Plenum, NY, (1995)
• S.Akkelin and Y.Sinyukov, Phys. Lett. B 356:525 (1995)
• S.Chapman and P.Scotto and U.Heinz, Heavy Ion Physics 1:1 (1995)


Wigner formalism and correlation predictions
• S.Pratt and T.Csorgo and J.Zimanyi, Phys. Rev. C 42:2646 (1990)
• S.Chapman and U.Heinz, Phys. Lett. B 340:250 (1994)


Use of K-dep. average source fn.
• G.Bertsch and P.Danielewicza and M.Herrmann, Phys. Rev. C 49:442 (1994)
• M.Herrmann and G.Bertsch, Phys. Rev. C 51:328 (1995)
• S.Chapman and P.Scotto and U.Heinz, Phys. Rev. Lett. 74:4400 (1995)



• F.Yano and S.Koonin, Phys. Lett. B 78:556 (1978)

Additional references