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D. Adamová,
G. Agakichiev,
H. Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A. Castillo,
A. Cherlin,
S. Damjanović,
T. Dietel, [......],
M. Šumbera,
H. Tilsner,
I. Tserruya,
J.P. Wessels,
T. Wienold,
B. Windelband,
J.P. Wurm,
W. Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Measurements of event-by-event fluctuations of the mean transverse momentum in PbAu collisions at 40, 80, and 158 are presented. A significant excess of mean pT fluctuations at mid-rapidity is observed over the expectation from statistically independent particle emission. The results are somewhat smaller than recent measurements at RHIC. A possible non-monotonic behavior of the mean pT fluctuations as function of collision energy, which may have indicated that the system has passed the critical point of the QCD phase diagram in the range of μB under investigation, has not been observed. The centrality dependence of mean pT fluctuations in PbAu is consistent with an extrapolation from pp collisions assuming that the non-statistical fluctuations scale with multiplicity. The results are compared to calculations by the rqmd and urqmd event generators.
Nuclear Physics A 10/2003; · 1.54 Impact Factor
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D Adamová,
G Agakichiev,
H Appelshäuser,
V Belaga,
P Braun-Munzinger, A Castillo,
A Cherlin,
S Damjanović,
T Dietel,
L Dietrich, [......],
M Sumbera,
H Tilsner,
I Tserruya,
J P Wessels,
T Wienold,
B Windelband,
J P Wurm,
W Xie,
S Yurevich,
V Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Based on an evaluation of data on pion interferometry and on particle yields at midrapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda(f) reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from the Alternating Gradient Synchrotron to the Relativistic Heavy Ion Collider.
Physical Review Letters 02/2003; 90(2):022301. · 7.37 Impact Factor
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H Appelshäuser,
D. Adamova,
G. Agakichiev,
V. Belaga,
P. Braun-Munzinger, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel,
L. Dietrich, [......],
M. Sumbera,
H. Tilsner,
Itzhak Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Results on event-by-event fluctuations of the mean transverse momentum and net charge in Pb-Au collisions, measured by the CERES Collaboration at CERN-SPS, are presented. We discuss the centrality and beam energy dependence and compare our data to cascade calculations.
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D. Adamova,
G. Agakichiev,
H Appelshäuser,
V. V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel, [......],
M. Sumbera,
H. Tilsner,
Itzhak Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. I. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Measurements of event-by-event fluctuations of the mean transverse momentum in Pb-Au collisions at 40, 80, and 158 A GeV/c are presented. A significant excess of mean p_T fluctuations at mid-rapidity is observed over the expectation from statistically independent particle emission. The results are somewhat smaller than recent measurements at RHIC. A possible non-monotonic behaviour of the mean p_T fluctuations as function of collision energy, which may have indicated that the system has passed the critical point of the QCD phase diagram in the range of mu_B under investigation, has not been observed. The centrality dependence of mean p_T fluctuations in Pb-Au is consistent with an extrapolation from pp collisions assuming that the non-statistical fluctuations scale with multiplicity. The results are compared to calculations by the RQMD and UrQMD event generators.
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J. P. Wessels,
D. Adamova,
G. Agakichiev,
H Appelshuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic, [......],
J. Stachel,
M. Sumbera,
H. Tilsner,
Itzhak Tserruya,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: In this talk latest results from the analysis of e+e- pairs emitted in Pb+Au collisions at 40 AGeV/c and a combined analysis of all data available at 158 AGeV/c are presented. The enhancement of low-mass e+e- pairs (m_ee>0.2 GeV/c^2) with respect to the expected yield from hadron decays first reported at 158 AGeV/c is also found at 40 AGeV/c and is even larger there. Comparing to various theoretical models based on pi-pi-annihilation, the data can only be reproduced, if the properties of the intermediate rho in the hot and dense medium are modified. Theoretically, the modification is linked to baryon density rather than temperature. Constraints from hadron data taken at the same beam energies indeed indicate a fireball evolution along a trajectory of higher baryon density at 40 AGeV/c, consistent with the observed larger enhancement factor.
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D. Adamová,
G. Agakichiev,
H. Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A. Castillo,
A. Cherlin,
S. Damjanović,
T. Dietel, [......],
M. Šumbera,
H. Tilsner,
I. Tserruya,
J.P. Wessels,
T. Wienold,
B. Windelband,
J.P. Wurm,
W. Xie,
S. Yurevich,
V.V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 A GeV. A detailed study of the Bertsch–Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum kt and in bins of the centrality of the collision. From these results we extract model-dependent information about the space–time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out.
Nuclear Physics A.
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D Adamová,
G. Agakichiev,
H Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel, [......],
M. Sumbera,
H. Tilsner,
I Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 A GeV. A detailed study of the Bertsch–Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum kt and in bins of the centrality of the collision. From these results we extract model-dependent information about the space–time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out.
Nuclear Physics A, v.714, 124-144 (2003).
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D Adamová,
G. Agakichiev,
H Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel, [......],
M. Sumbera,
H. Tilsner,
I Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: In this talk latest results from the analysis of e ‘e--pairs emitted in Pb+Au collisions at, 40 AGeV/c and a combined analysis of all data available at 158 AGeV/c are presented. The enhancement of low-mass e+e - -pairs (mee >0.2 GeV/c2) with respect to the expected yield from hadron decays first reported at 158 AGeV/c is also found at 40 AGeV/c and is mm larger t,here. Comparing to various theoretical models based on ~T+x- annihilation, the data carp only 1x1 reproduced. if the prop&es of the intermediate p in the hot and :ittilsti !urdium are n~otlificd. Throret icdlly. I he modific~ation is linked to baryon densit> rdt her ! haI1 rf~rI!iJeI,aturc‘. Cr,l!5tI’:lil?tS from !luth111 dilta t dWl1 ;It thP ‘XliC hP?lIli cwqif5 ;iitlerii iliciicate a Ilrt~tAl t~vollitiofl dlolig ki trk3jwI.orv r~f llighrr lxn’riri :lr~l!SiiJ ;~t li! :1GeV/c. consist,ent with the observed la.rger enhancement factor.
Nuclear Physics A, v.715, 262c-271c (2003).
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D Adamová,
G. Agakichiev,
H Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel, [......],
M. Sumbera,
H. Tilsner,
I Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: A study of differential elliptic event anisotropies (2) of charge particles and high-pT pions in 158 AGeV/c Pb+Au collisions is presented. Results from correlations with respect to the event plane and from two-particle azimuthal correlations are compared. The latter give systematically higher 2 values at pT >1.2 GeV/cproviding possibly an evidence of a non-flow semihard component.
Nuclear Physics A, v.715, 615-618 (2003).
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D Adamová,
G. Agakichiev,
H Appelshäuser,
V. Belaga,
P. Braun-Munzinger,
R. Campagnolo, A Castillo,
A. Cherlin,
S. Damjanovic,
T. Dietel, [......],
M. Sumbera,
H. Tilsner,
I Tserruya,
J. P. Wessels,
T. Wienold,
B. Windelband,
J P Wurm,
W Xie,
S. Yurevich,
V. Yurevich
[show abstract]
[hide abstract]
ABSTRACT: Measurements of event-by-event fluctuations of the mean transverse momentum in Pb–Au collisions at 40, 80, and 158 AGeV/c are presented. A significant excess of mean pT fluctuations at mid-rapidity is observed over the expectation from statistically independent particle emission. The results are somewhat smaller than recent measurements at RHIC. A possible non-monotonic behavior of the mean pT fluctuations as function of collision energy, which may have indicated that the system has passed the critical point of the QCD phase diagram in the range of µB under investigation, has not been observed. The centrality dependence of mean pT fluctuations in Pb–Au is consistent with an extrapolation from pp collisions assuming that the non-statistical fluctuations scale with multiplicity. The results are compared to calculations by the RQMD and URQMD event generators.
Nuclear Physics A, v.727, 97-119 (2003).
