ATLAS measured charged-particle production in 9.62 TeV p-O collisions, yielding a fiducial pO cross section of 396 mb and extrapolated p-air inelastic cross section of 406 mb, with distributions an order of magnitude more precise than hadronic model differences.
Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
Measurements are presented from proton-proton collisions at centre-of-mass energies of sqrt(s) = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase-space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo models, including a new AMBT1 PYTHIA 6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the Monte Carlo models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with pT >100 MeV, is measured to be 3.483 +- 0.009 (stat) +- 0.106 (syst) at sqrt(s) = 0.9 TeV and 5.630 +- 0.003 (stat) +- 0.169 (syst) at sqrt(s) = 7 TeV.
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representative citing papers
Using a phenomenologically motivated spectrum shift model, the authors estimate partonic Δp_T loss and demonstrate its correlation with initial energy density ε_Bj across collision energies, then predict high-pT v2 that agrees with data.
Reciprocal symmetry f_s(z)=f_s(1/z) implies local constraints on multiplicity distributions at n=<n> that hold to leading order in ATLAS data, plus a model-independent entanglement entropy expression S=ln<n>+1-½∫e^{-z}f_s²(z)dz+O(f_s³).
The generalized dipole model fits entropy and mean multiplicity data from proton-proton collisions significantly better than the standard 1D Mueller dipole model.
An approximate formula for the entropy of the negative binomial distribution is provided, with up to ~20% deviation from exact values for extreme parameters.
citing papers explorer
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Measurement of charged-particle production in $\sqrt{s_\text{NN}}=9.62$ TeV proton-oxygen collisions as a probe of cosmic-ray air showers with the ATLAS detector
ATLAS measured charged-particle production in 9.62 TeV p-O collisions, yielding a fiducial pO cross section of 396 mb and extrapolated p-air inelastic cross section of 406 mb, with distributions an order of magnitude more precise than hadronic model differences.
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Probing the Dependence of Partonic Energy Loss on the Initial Energy Density of the Quark Gluon Plasma
Using a phenomenologically motivated spectrum shift model, the authors estimate partonic Δp_T loss and demonstrate its correlation with initial energy density ε_Bj across collision energies, then predict high-pT v2 that agrees with data.
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Higher-order local constraints from reciprocal symmetry and entanglement entropy of charged-particle multiplicity distributions in $pp$ collisions
Reciprocal symmetry f_s(z)=f_s(1/z) implies local constraints on multiplicity distributions at n=<n> that hold to leading order in ATLAS data, plus a model-independent entanglement entropy expression S=ln<n>+1-½∫e^{-z}f_s²(z)dz+O(f_s³).
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Entropy and mean multiplicity from dipole models in the high energy limit
The generalized dipole model fits entropy and mean multiplicity data from proton-proton collisions significantly better than the standard 1D Mueller dipole model.
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An approximate formula for the entropy of the negative binomial distribution
An approximate formula for the entropy of the negative binomial distribution is provided, with up to ~20% deviation from exact values for extreme parameters.