Abstract
The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 AGeV has been measured by the NA49 experiment. The preliminary results are compared to model predictions from proton source distributions of static thermal Gaussian sources and the transport models of rqmd and venus. We obtain an effective proton source size \( {\sigma _{{\mathbf{eff}}}} = 4.0 \pm 0.15({\mathbf{stat}}.)_{ - 0.18}^{ + 0.06}({\mathbf{syst}}.) \) fm. The rqmd model underpredicts the correlation function ( \( {\sigma _{{\mathbf{eff}}}} = 4.41 \) fm), while the venus model overpredicts the correlation function ( \( {\sigma _{{\mathbf{eff}}}} = 3.55 \) fm).
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For a chaotic Gaussian source, is close to the non-relativistic approximation of the effective size in the source rest frame, \( \sqrt[6]{{{{(\sigma _{{\mathbf{x,y}}}^2 + \frac{T}{{2m}}\sigma _t^2)}^2} \cdot (\sigma _z^2 + \frac{T}{{2m}}\sigma _t^2)}} \) Where \( \frac{T}{m} \) is the one-dimensional mean squared velocity of the thermal protons, and \( \frac{T}{2m} \) is that of the close pairs.
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Wang, F. (1999). Two-Proton Correlations from Pb+Pb Central Collisions. In: Bauer, W., Westfall, G.D. (eds) Advances in Nuclear Dynamics 5. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-4719-8_11
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DOI: https://doi.org/10.1007/978-1-4615-4719-8_11
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