Related Experiment Video
Updated: Mar 19, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at
J Adam1, D Adamová2, M M Aggarwal3
1Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
Abstract:
The pseudorapidity density of charged particles, dN_{ch}/dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02 TeV. For the 5% most central collisions, we measure a value of 1943±54. The rise in dN_{ch}/dη as a function of sqrt[s_{NN}] is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dN_{ch}/dη as a function of the average number of participant nucleons, ⟨N_{part}⟩, calculated in a Glauber model, is compared with the previous measurement at sqrt[s_{NN}]=2.76 TeV. A constant factor of about 1.2 describes the increase in dN_{ch}/dη from sqrt[s_{NN}]=2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%-80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.
Related Concept Videos
Nuclear Stability
To hold positively charged protons together...
Significance of Center of Mass
Atomic Nuclei: Nuclear Magnetic Moment
Energy Associated With a Charge Distribution
Atomic Nuclei: Nuclear Spin State Population Distribution
Atomic Radii and Effective Nuclear Charge

