Estimation of hydrodynamical model parameters from the invariant spectrum and the Bose-Einstein correlations of $\pi$-mesons produced in ($\pi^{+}/K^{+})p$ interactions at 250 GeV/c

Agababyan, N.M.; Dziunikowska, K.; Hakobyan, R.Sh.; Smirnova, L.N.; Rizatdinova, F.K.; Olkiewicz, K.; Garutchava, Z.Sh.; Tomaradze, A.G.; De Wolf, E.A.; Atayan, M.R.; Tikhonova, L.A.; Kisielewska, D.; Zotkin, S.A.; Csörgő, T.; Shabalina, E.K.; Tabidze, M.D.; Verbeure, F.; Kittel, W.; Gulkanyan, H.R.; Tkabladze, A.V.; Karamyan, J.K.; Metreveli, Z.V.; Mehrabyan, S.S.; Endler, A.M.F.

doi:10.1016/S0370-2693(98)00072-0

Article
Report number	hep-ex/9711009 ; HEN-405 ; HEN-405
Title	Estimation of hydrodynamical model parameters from the invariant spectrum and the Bose-Einstein correlations of $\pi$-mesons produced in ($\pi^{+}/K^{+})p$ interactions at 250 GeV/c
Author(s)	Agababyan, N.M. (Yerevan Phys. Inst.) ; Atayan, M.R. (Yerevan Phys. Inst.) ; Csörgő, T. (Budapest, RMKI) ; De Wolf, E.A. (Antwerp U.) ; Dziunikowska, K. (Cracow, INP) ; Endler, A.M.F. (Rio de Janeiro, CBPF) ; Garutchava, Z.Sh. (Tbilisi State U.) ; Gulkanyan, H.R. (Yerevan Phys. Inst.) ; Hakobyan, R.Sh. (Yerevan Phys. Inst.) ; Karamyan, J.K. (Yerevan Phys. Inst.) ; Kisielewska, D. (Cracow, INP) ; Kittel, W. (Nijmegen U. ; Nikhef, Amsterdam) ; Mehrabyan, S.S. (Yerevan Phys. Inst.) ; Metreveli, Z.V. (Tbilisi State U.) ; Olkiewicz, K. (Cracow, INP) ; Rizatdinova, F.K. (Moscow, ITPM) ; Shabalina, E.K. (Moscow, ITPM) ; Smirnova, L.N. (Moscow, ITPM) ; Tabidze, M.D. (Tbilisi State U.) ; Tikhonova, L.A. (Moscow, ITPM) ; Tkabladze, A.V. (Tbilisi State U.) ; Tomaradze, A.G. (Tbilisi State U.) ; Verbeure, F. (Antwerp U.) ; Zotkin, S.A. (Moscow, ITPM)
Publication	1998
Imprint	19 Nov 1997
Number of pages	14
Note	latex, 14 pages, 5 figures
In:	Phys. Lett. B 422 (1998) 359
DOI	10.1016/S0370-2693(98)00072-0
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN SPS ; NA22
Free keywords	K+ p ; pi+ p
Abstract	The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250 GeV/c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity <u_t> = 0.20(7), and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be Delta eta = 1.36(2). Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of <tau_f> = 1.4(1) fm/c and its transverse geometrical rms radius, R_G (rms)=1.2(2) fm.