Freeze-out radii extracted from three-pion cumulants in pp, p-Pb and Pb-Pb collisions at the LHC
arXiv:1404.1194 · doi:10.1016/j.physletb.2014.10.034
Abstract
In high-energy collisions, the spatio-temporal size of the particle production region can be measured using the Bose-Einstein correlations of identical bosons at low relative momentum. The source radii are typically extracted using two-pion correlations, and characterize the system at the last stage of interaction, called kinetic freeze-out. In low-multiplicity collisions, unlike in high-multiplicity collisions, two-pion correlations are substantially altered by background correlations, e.g. mini-jets. Such correlations can be suppressed using three-pion cumulant correlations. We present the first measurements of the size of the system at freeze-out extracted from three-pion cumulant correlations in pp, p-Pb and Pb-Pb collisions at the LHC with ALICE. At similar multiplicity, the invariant radii extracted in p-Pb collisions are found to be 5-15% larger than those in pp, while those in Pb-Pb are 35-55% larger than those in p-Pb. Our measurements disfavor models which incorporate substantially stronger collective expansion in p-Pb as compared to pp collisions at similar multiplicity.
25 pages, 6 captioned figures, 1 table, authors from page 19, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/1056
References in corpus (7)
- PYTHIA 6.4 Physics and Manual
- Observation of long-range near-side angular correlations in proton-lead collisions at the LHC
- Correlations from hydrodynamic flow in p-Pb collisions
- Therminator: Thermal heavy-Ion generator
- Explanation of systematics of CMS p+Pb high multiplicity di-hadron data at TeV
- Size of the emission source and collectivity in ultra-relativistic p-Pb collisions
- Search for supersymmetry in events with photons and low missing transverse energy in pp collisions at sqrt(s) = 7 TeV