Azimuth quadrupole component spectra on transverse rapidity y(t) for identified hadrons from Au-Au collisions at root s(N) (N)=200 GeV

作者：Trainor Thomas A^*

来源：Physical Review C, 2008, 78(6): 064908.

DOI：10.1103/PhysRevC.78.064908

I present the first isolation of azimuth quadrupole components from published nu(2)(p(t)) data (called elliptic flow) as spectra on transverse rapidity y(t) for identified pions, kaons, and Lambda 's/protons from minimum-bias Au-Au collisions at 200 GeV. The form of the spectra on yt indicates that the three hadron species are emitted from a common boosted source with boost Delta y(t0) similar to 0.6. The quadrupole spectra have a Levy form similar to the soft component of the single-particle spectrum, but with significantly reduced (similar to 0.7 times) slope parameters T. Comparison of quadrupole spectra with single-particle spectra suggests that the quadrupole component comprises a small fraction (< 5%) of the total hadron yield, contradicting the hydrodynamic picture of a thermalized, flowing bulk medium. The form of nu(2)(p(t)) is, within a constant factor, the product of p(t)(') (p(t) in the boost frame) times the ratio of quadrupole spectrum to single-particle spectrum. That ratio in turn implies that above 0.5 GeV/c, the form of nu(2)( p(t)) is dominated by the hard component of the single-particle spectrum (interpreted as being due to minijets). It is therefore unlikely that the so-called constituent-quark scaling attributed to nu(2) is relevant to soft hadron production mechanisms (e.g., chemical freeze-out).

• 出版日期2008-12