Abstract : Two-particle pseudorapidity correlations are measured in $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV Pb+Pb, $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV $p$+Pb, and $\sqrt{s}$ = 13 TeV $pp$ collisions at the LHC, with total integrated luminosities of approximately 7 $\mu\mathrm{b}^{-1}$, 28 $\mathrm{nb}^{-1}$, and 65 $\mathrm{nb}^{-1}$, respectively. The correlation function $C_{\rm N}(\eta_1,\eta_2)$ is measured as a function of event multiplicity using charged particles in the pseudorapidity range $|\eta|<2.4$. The correlation function contains a significant short-range component, which is estimated and subtracted. After removal of the short-range component, the shape of the correlation function is described approximately by $1+\langle{a_1^2}\rangle \eta_1\eta_2$ in all collision systems over the full multiplicity range. The values of $\sqrt{\langle{a_1^2}\rangle}$ are consistent between the opposite-charge pairs and same-charge pairs, and for the three collision systems at similar multiplicity. The values of $\sqrt{\langle{a_1^2}\rangle}$ and the magnitude of the short-range component both follow a power-law dependence on the event multiplicity. The $\eta$ distribution of the short-range component, after symmetrizing the proton and lead directions in $p$+Pb collisions, is found to be smaller than that in $pp$ collisions with comparable multiplicity.
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Journal articles
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http://hal.in2p3.fr/in2p3-01338736
Contributor : Claudine Bombar <>
Submitted on : Wednesday, June 29, 2016 - 10:35:04 AM
Last modification on : Friday, August 9, 2019 - 4:32:02 PM

### Citation

M. Aaboud, Z. Barnovska, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Measurement of forward-backward multiplicity correlations in lead-lead, proton-lead and proton-proton collisions with the ATLAS detector. Physical Review C, American Physical Society, 2017, 95, pp.064914. ⟨https://journals.aps.org/prc/abstract/10.1103/PhysRevC.95.064914⟩. ⟨10.1103/PhysRevC.95.064914⟩. ⟨in2p3-01338736⟩

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