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Peter Christiansen Profile

Peter Christiansen

Professor

Peter Christiansen Profile

Azimuthally-differential pion femtoscopy relative to the third harmonic event plane in Pb–Pb collisions at sNN=2.76TeV

Author

  • S Acharya
  • Jonatan Adolfsson
  • Peter Christiansen
  • Martin Ljunggren
  • Anders Oskarsson
  • Tuva Richert
  • David Silvermyr
  • Evert Stenlund
  • Vytautas Vislavicius
  • S. Zou

Summary, in English

Azimuthally-differential femtoscopic measurements, being sensitive to spatio-temporal characteristics of the source as well as to the collective velocity fields at freeze out, provide very important information on the nature and dynamics of the system evolution. While the HBT radii oscillations relative to the second harmonic event plane measured recently reflect mostly the spatial geometry of the source, model studies have shown that the HBT radii oscillations relative to the third harmonic event plane are predominantly defined by the velocity fields. In this Letter, we present the first results on azimuthally-differential pion femtoscopy relative to the third harmonic event plane as a function of the pion pair transverse momentum kT for different collision centralities in Pb–Pb collisions at sNN=2.76 TeV. We find that the Rside and Rout radii, which characterize the pion source size in the directions perpendicular and parallel to the pion transverse momentum, oscillate in phase relative to the third harmonic event plane, similar to the results from 3+1D hydrodynamical calculations. The observed radii oscillations unambiguously signal a collective expansion and anisotropy in the velocity fields. A comparison of the measured radii oscillations with the Blast-Wave model calculations indicate that the initial state triangularity is washed-out at freeze out. © 2018 European Organization for Nuclear Research

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2018

Language

English

Pages

320-331

Publication/Series

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

Volume

785

Document type

Journal article

Publisher

Elsevier

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0370-2693