Forward-backward multiplicity correlations in pp collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV

20 May 2014, 16:30
spectrum (darmstadtium)



Board: I-03
Poster Correlations and Fluctuations Poster session


Igor Altsybeev (St. Petersburg State University (RU)) Sudipan De (Department of Atomic Energy (IN))


Forward-backward multiplicity correlations have been measured with the ALICE detector at the LHC in pp minimum bias collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV. The measurement is performed in the central pseudorapidity region ($|\eta| < 0.8$) for $p_{\mathrm{T}}>0.3$ GeV/$c$. The multiplicity correlation strength ($b_{\rm corr}$) was obtained using pairs of separate pseudorapidity and azimuthal windows and studied as a function of the separation distance between the windows in $\eta$ and $\varphi$, as well as of the size of the windows. A considerable increase of the correlation strength with the collision energy is found. Two types of contributions -- the short-range (SR) and the long-range (LR) -- are observed. The energy dependence of $b_{\rm corr}$ is found to be weak for the SR component and strong for the LR component. The $b_{\rm corr}$ is also studied in different transverse momentum intervals, which have the same mean multiplicity. It is found that both SR and LR contributions to $b_{\rm corr}$ increase with increasing minimum threshold of $p_{\mathrm{T}}$. The results are compared to PYTHIA and PHOJET Monte Carlo event generators and to the string-based empirical model.
On behalf of collaboration: ALICE

Primary authors

Igor Altsybeev (St. Petersburg State University (RU)) Sudipan De (Department of Atomic Energy (IN))

Presentation Materials