4 research outputs found
Theoretical analysis for the apparent discrepancy between pbarp and pp data in charged particle forward-backward multiplicity correlations
The strength of charged particle forward-backward multiplicity correlation in
pbar+p and p+p collisions at s^1/2 = 200 GeV is studied by PYTHIA 6.4 and
compared to the UA5 and STAR data correspondingly. It is turned out that a
factor of 3-4 apparent discrepancy between UA5 and STAR data can be attributed
to the differences in detector acceptances and observing bin interval in both
experiments. A mixed event method is introduced and used to calculate the
statistical correlation strength and the dynamical correlation strengths
stemming from the charge conservation, four- momentum conservation, and decay,
respectively. It seems that the statistical correlation is much larger than
dynamical one and the charge conservation, four-momentum conservation and decay
may account for most part of the dynamical correlation. In addition, we have
also calculated the correlation strength by fitting the charged particle
multiplicity distribution from PYTHIA to the Negative Binomial Distribution and
found that the result agrees well with the correlation strength calculated by
mixed events.Comment: 5 pages, 4 figure
Charged particle elliptic flow in p+p collisions at LHC energies in a transport model PACIAE
The parton and hadron cascade model PACIAE based on PYTHIA was used to
investigate the charged particle elliptic flow in minimum bias pp collisions at
the LHC energies. The strings were distributed randomly in the transverse
ellipsoid of the pp collision system with major axis of (proton radius) and
minor axis of before parton rescattering. The charged particle
elliptic flow as a function of the random number and transverse momentum
were investigated. The calculated as a function of
reaction energy increases monotonously with increasing reaction energy up to
7 TeV and then turns to saturation. With the parton-parton cross
section enlarges three times in parton rescattering, the rapidity integrated
charged particle elliptic flow may reach 0.025 at 2 GeV/c in the
minimum bias pp collisions at =7 TeV.Comment: 7 pages, 4 figure