Peter Christiansen
Professor
Longitudinal and azimuthal evolution of two-particle transverse momentum correlations in Pb-Pb collisions at √sNN= 2.76 TeV
Author
Summary, in English
This paper presents the first measurements of the charge independent
(CI) and charge dependent (CD) two-particle transverse momentum
correlators G2CI and G2CD in Pb–Pb collisions at √SNN=2.76 TeV by the ALICE collaboration. The two-particle transverse momentum correlator G2 was introduced as a measure of the momentum current transfer between
neighboring system cells. The correlators are measured as a function of
pair separation in pseudorapidity (Δη) and azimuth (Δφ) and as a function of collision centrality. From peripheral to central collisions, the correlator G2CI exhibits a longitudinal broadening while undergoing a monotonic azimuthal narrowing. By contrast, G2CD exhibits a narrowing along both dimensions. These features are not
reproduced by models such as HIJING and AMPT. However, the observed
narrowing of the correlators from peripheral to central collisions is
expected to result from the stronger transverse flow profiles produced
in more central collisions and the longitudinal broadening is predicted
to be sensitive to momentum currents and the shear viscosity per unit of
entropy density η/s of the matter produced in the collisions. The observed broadening is
found to be consistent with the hypothesized lower bound of η/s and is in qualitative agreement with values obtained from anisotropic flow measurements.
(CI) and charge dependent (CD) two-particle transverse momentum
correlators G2CI and G2CD in Pb–Pb collisions at √SNN=2.76 TeV by the ALICE collaboration. The two-particle transverse momentum correlator G2 was introduced as a measure of the momentum current transfer between
neighboring system cells. The correlators are measured as a function of
pair separation in pseudorapidity (Δη) and azimuth (Δφ) and as a function of collision centrality. From peripheral to central collisions, the correlator G2CI exhibits a longitudinal broadening while undergoing a monotonic azimuthal narrowing. By contrast, G2CD exhibits a narrowing along both dimensions. These features are not
reproduced by models such as HIJING and AMPT. However, the observed
narrowing of the correlators from peripheral to central collisions is
expected to result from the stronger transverse flow profiles produced
in more central collisions and the longitudinal broadening is predicted
to be sensitive to momentum currents and the shear viscosity per unit of
entropy density η/s of the matter produced in the collisions. The observed broadening is
found to be consistent with the hypothesized lower bound of η/s and is in qualitative agreement with values obtained from anisotropic flow measurements.
Department/s
- Particle and nuclear physics
- eSSENCE: The e-Science Collaboration
Publishing year
2020-03-20
Language
English
Publication/Series
Physics Letters B
Volume
804
Document type
Journal article
Publisher
Elsevier
Topic
- Subatomic Physics
Status
Published
ISBN/ISSN/Other
- ISSN: 0370-2693