# Angular power spectrum of heavy ion collisions

Machado, M. (Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark) (Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark) ; Damgaard, P.H. (Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark) (Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark) ; Gaardhøje, J.J. (Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark) ; Bourjau, C. (Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark)

29 May 2019

Abstract: Particles produced in heavy ion collisions carry information about anisotropies present already in the early state of the system and play a crucial role in understanding the quark gluon plasma and its evolution. We explore the angular power spectrum of particle multiplicities in such heavy ion collisions to extract fluctuations in particle multiplicities on the surface a sphere. Results are presented for Pb-Pb data at $\sqrt{{s}_{NN}}=2.76\phantom{\rule{0.16em}{0ex}}\mathrm{TeV}$, extracted from the ALICE open data portal. We find that odd modes of the power spectrum display a power-law behavior with corresponding index $\beta$, which is found to be close to unity. We also demonstrate that the angular power spectrum allows us to extract accurately the flow coefficients of noncentral collisions.

Published in: Physical Review C 99 (2019)