J/ψ suppression at forward rapidity in Pb-Pb collisions at √s(NN) = 2.76 TeV

Area of Science:

• High-energy nuclear physics
• Quark-gluon plasma studies
• Particle physics

Background:

• Heavy-ion collisions probe the state of matter under extreme conditions.
• J/ψ mesons are sensitive probes of the quark-gluon plasma.
• Previous studies indicated J/ψ suppression at lower energies.

Purpose of the Study:

• To measure inclusive J/ψ production in Pb-Pb collisions at √s(NN) = 2.76 TeV.
• To investigate the J/ψ nuclear modification factor (N(J/ψ)/N(pp)) as a function of centrality.
• To compare results with lower energy data and theoretical models.

Main Methods:

• Utilizing the ALICE detector at the Large Hadron Collider.
• Analyzing J/ψ → μ⁺μ⁻ decays in Pb-Pb and pp collisions.
• Calculating the nuclear modification factor by normalizing to binary nucleon-nucleon collisions.

Main Results:

• Observed significant suppression of inclusive J/ψ yield in Pb-Pb compared to scaled pp collisions.
• Measured a nuclear modification factor of 0.545 ± 0.032(stat) ± 0.083(syst) for central collisions (0-80%).
• Found no significant centrality dependence of the J/ψ nuclear modification factor.

Conclusions:

• The observed J/ψ suppression at 2.76 TeV differs from lower energy results.
• Data are consistent with models incorporating J/ψ production from deconfined charm quarks.
• Suggests charmonium interaction and potential regeneration within the quark-gluon plasma.