Bose-Einstein correlation of positive kaon pairs in E859--Extended results and model comparisons Page: 2 of 7
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V. aandolo / Nudear Physics A590 (1995) 459c-464c
The E859 apparatus is described in . A 3-Q r/K separation below 1.8 GeV/c was
obtained in a 25 msr rotating magnetic spectrometer. The TMA is a 2988-element pad
chamber that almost completely surrounds the target and is sensitive to the total charged
multiplicity in the event. This detector served as our first-level centrality trigger; we cut
on the upper 20% of the charged multiplicity distribution. A second-level trigger, with
40 s online PID capability, was added to the E802 experimental apparatus . This
trigger enhanced the collection rate for K+-pairs by a factor of 12.
We examined experimental data sets consisting of s 50000 K+ pairs and s 110000 s+
pairs, with rarely more than one pair in an event. Data were corrected with the standard
Gamow factor. A two-particle efficiency correction, parameterized from the data in terms
of the spatial separation of the tracks , was also applied. All correlation functions were
fit in the center of mass frame of the participants (Y = 1.25). Careful study of parameter
dependence on the various correction factors leads us to estimate a systematic error for
all parameters of s 5-10% .
300,000 ARC  events and 30,000 RQMD  events were generated with geomet-
rically distributed impact parameter and cut on the experimental acceptance and cen-
trality trigger. Remaining phase-space points were binned by impact parameter (0.2 fin
bins for the pions, 0.5fm bins for the kaons). We imposed BEC on the models using
Pratt's Wigner-density formalism 112]. Pairs were created by mixing the single-particle
phase-space points in each impact parameter bin. Weights were calculated for each pair
by symmetrizing the Coulomb wavefunction. Results presented here suffer from overuse
of single-particle phase-space points in generating the model pairs. This caused super-
Poisson fluctuations in the models' relative-momentum distributions, which in turn led
to large values of X2/dof and unrealistically small error bars.
In order to examine the kinematic dependence of extracted source parmeters, the pion
data samples were split in two by applying a cut at 350 MeV/c in the single-particle PT
We present results for three correlation functional forms derived from different Gaussian
Rr : C2 = 1 + Aexp(-(QR)2 - (qor)2) (1)
RLRT : C2 = 1 + Aexp(-(QLRL)2 - (QTRT)2) (2)
RLRTRT. : C2 = 1 + A exp(-(QLRL)2 - (QTRT,)2 - (QT.RT.)2) (3)
Results from 1D  and 2D (14] parameterizations have been presented previously.
Correlation functions for both 2D parameterizations were fit to all data sets. Confidence
contours for these parameterizations are presented in figure 1. The 3D parameterization
was only tested on the full data sets; results are presented in figure 2. All fit results are
summarized tables 1-3.
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Cianciolo, V. Bose-Einstein correlation of positive kaon pairs in E859--Extended results and model comparisons, report, December 31, 1995; Upton, New York. (digital.library.unt.edu/ark:/67531/metadc669760/m1/2/: accessed November 19, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.