Collective Nuclear Vibrations and Initial State Shape Fluctuations in Central Pb + Pb Collisions: Resolving the v2 to v3 Puzzle

We have studied, for the first time, the influence of the collective quantum effects in the nuclear wavefunctions on the azimuthal anisotropy coefficients ∈_2,3 in the central Pb + Pb collisions at the LHC energies. With the help of the energy weighted sum rule, we demonstrate that the classical treatment with the Woods—Saxon nuclear density overestimates the mean square quadrupole moment of the ²⁰⁸Pb nucleus by a factor of ~2.2. The Monte Carlo Glauber simulation of the central Pb + Pb collisions accounting for the restriction on the quadrupole moment leads to ∈₂/∈₃ ≈ 0.8 which allows to resolve the v₂-to-v₃ puzzle.