New Cross Term in the Two-Particle Hanbury-Brown–Twiss Correlation Function in Ultrarelativistic Heavy-Ion Collisions

Chapman, Scott T.; Scotto, Pierre; Heinz, Ulrich

doi:10.1103/physrevlett.74.4400

Cited by 170 publications

(310 citation statements)

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“…[20]) that, in the LCMS, the components Q t side and Q l reflect only the difference in emission space of the two pions, while Q tout depends on the difference in emission time as well. Indeed, the scalar product between Q and the four-vector…”

Section: The Longitudinally Comoving Systemmentioning

confidence: 99%

Transverse and longitudinal Bose-Einstein correlations in hadronic Z $^0$ decays

Abbiendi¹,

Ackerstaff²,

Åkesson³

et al. 2000

Eur. Phys. J. C

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Bose-Einstein correlations in pairs of identical charged pions produced in a sample of 4.3 million Z 0 hadronic decays are studied as a function of the three components of the momentum difference, transverse ("out" and "side") and longitudinal with respect to the thrust direction of the event. A significant difference between the transverse, r t side , and longitudinal, r l , dimensions is observed, indicating that the emitting source of identical pions, as observed in the Longitudinally CoMoving System, has an elongated shape. This is observed with a variety of selection techniques. Specifically, the values of the parameters obtained by fitting the extended Goldhaber parametrisation to the correlation function C ′ = C DATA /C MC for two-jet events, selected with the Durham algorithm and resolution parameter y cut = 0.04, are r t side = (0.809 ± 0.009 (stat) +0.019 −0.032 (syst)) fm, r l = (0.989 ± 0.011 (stat) +0.030 −0.015 (syst)) fm and r l /r t side = 1.222 ± 0.027 (stat) +0.075 −0.012 (syst). The results are discussed in the context of a recent model of Bose-Einstein correlations based on string fragmentation.

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Section: The Longitudinally Comoving Systemmentioning

confidence: 99%

Transverse and longitudinal Bose-Einstein correlations in hadronic Z $^0$ decays

Abbiendi¹,

Ackerstaff²,

Åkesson³

et al. 2000

Eur. Phys. J. C

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“…The time parameters τ 0 , ∆τ were fixed together with the other parameters from the correlation radii, whereas the longitudinal width ∆η = 1.3 of the density profile was fixed by adjusting the width of dN/dy. The correlation radii were calculated numerically from the "model-independent expressions" [2]. When calculating the single-particle spectrum resonances were taken into account as in [7]; since we fitted the h − spectrum we also added negative kaons and antiprotons.…”

Section: The Modelmentioning

confidence: 99%

“…Assuming thermalization and collective transverse flow at freeze-out, these two features can be extracted separately by combining single-particle m ⊥ -spectra and two-particle Bose-Einstein correlations [1][2][3][4]. Particles of non-zero transverse momentum are emitted from a fireball region which moves outwards transversely; in the local comoving frame their transverse momentum is lower, resulting in an enhanced Boltzmann factor.…”

Section: Motivationmentioning

confidence: 99%

“…They carry information about the final state of the fireball which one can use to reconstruct this state and thus obtain boundary conditions for back-extrapolation into earlier stages of its evolution. In this way one can examine the question whether or not a quark-gluon plasma was created.Assuming thermalization and collective transverse flow at freeze-out, these two features can be extracted separately by combining single-particle m ⊥ -spectra and two-particle Bose-Einstein correlations [1][2][3][4]. Particles of non-zero transverse momentum are emitted from a fireball region which moves outwards transversely; in the local comoving frame their transverse momentum is lower, resulting in an enhanced Boltzmann factor.…”

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confidence: 99%

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Dynamics and sizes of the fireball at freeze-out

Tomášik¹,

Wiedemann²,

Heinz³

2000

Nuclear Physics A

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CERN-TH/99-216 TPR-99-11 nucl-th/9907075Analyzing the m ⊥ -spectrum and two-particle correlations of negative hadrons from 158 AGeV/c Pb+Pb collisions at slightly forward rapidities we find a (thermal) freeze-out temperature of about 100 MeV and transverse flow withv ⊥ ≈ 0.55c. The M ⊥ -dependence of the correlation radii prefers a box-like transverse density profile over a Gaussian. From an analysis of the pion phase-space density we find µ π ≈ 60 MeV at thermal freeze-out. MOTIVATIONIn relativistic heavy-ion collisions the momenta of the escaping hadrons are fixed at the point of "thermal freeze-out". They carry information about the final state of the fireball which one can use to reconstruct this state and thus obtain boundary conditions for back-extrapolation into earlier stages of its evolution. In this way one can examine the question whether or not a quark-gluon plasma was created.Assuming thermalization and collective transverse flow at freeze-out, these two features can be extracted separately by combining single-particle m ⊥ -spectra and two-particle Bose-Einstein correlations [1][2][3][4]. Particles of non-zero transverse momentum are emitted from a fireball region which moves outwards transversely; in the local comoving frame their transverse momentum is lower, resulting in an enhanced Boltzmann factor. Transverse flow thus flattens the m ⊥ -spectrum. A given spectral slope can, however, be reproduced by different combinations of flow and temperature, because larger flow can be compensated for by lower temperature and vice versa. On the other hand, the sizes of the regions emitting particles of given momentum (homogeneity regions, measured by correlation radii) are controlled by the expansion velocity gradients. The natural velocity measure is given by the chaotic thermal motion; increasing T and the transverse flow (velocity gradients) together at the proper rate will thus not change the resulting correlation radii. In summary, T and v ⊥ are anticorrelated by a given spectral slope, but correlated by the measured homogeneity sizes. Exploiting both types of correlations their values can be determined unambiguously. This method was used for analyzing the data from central Pb+Pb collisions at 158 AGeV/c taken by the NA49 collaboration [4].

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“…At y=0 R outlong should be identically zero [7] and so we ignore it in this paper since the data are close to mid-rapidity. Figure 1 shows kaon, pion and proton phase space densities versus the transverse mass m T for Au+Au and Pb+Pb collisions at √ s nn = 5 and 17GeV respectively.…”

Section: Methodsmentioning

confidence: 99%