QM 09 Abstract proposal (oral presentation)

Title: Experimental suggestions of collective flow in p+p collisions at RHIC

Author: Z. Chajecki (for the STAR Collaboration)

Abstract:
Claims for the creation of a partially thermalized state of "matter" in heavy ion collisions at RHIC depend strongly on the inference of hydro-like flow in these collisions. In central collisions, this inference is itself prompted by two-particle femtoscopy and spectral shapes in soft sector.  We have performed  identical measurements of these signals in p+p collisions at $\sqrt{s}=$ 200 GeV.  Two-pion correlations may be understood as a combination of femtoscopic ("HBT") effects and phasespace restrictions due to energy and momentum conservation; we disentangle these contributions. Accounting for the same phasespace restrictions in single-particle distributions leads to a re-interpretion of the multiplicity evolution of the spectra.  In particular, both the $m_T$ spectra and the HBT effects are consistent with a flow-dominated freezeout scenario in p+p collisions, very similar to that from heavy ion collisions.  These results raise important questions regarding the existence, nature and timescale of thermalization and collective motion in all ultrarelativistic collisions. 

A) Data set: p+p and d+Au @ 200 GeV and published data from Au+Au@200GeV

B) Physics bullets:

• two-particle low-Q correlations contain HBT and correlation-law effects.
  Both must be accounted for, in order to understand the correlations.
• If there are correlation-law effects in 2-particle correlations,  there MUST
  be analogous effects in single-particle correlations.  We account  for these.
• p+p collisions display very similar flow signals-- HBT and spectra--
      as Au+Au collisions at RHIC
  
  - See also the summary of our paper proposal.

References:

[1] HBT in pp & dAu @ 200GeV in STAR - Paper proposal

[2] Z. Chajecki and M. Lisa, ArXiv:0803.0022, 0807.3569