First measurement of D^*+ vector spin alignment in Pb-Pb collisions at \mathbf√s_{\rm NN} = 5.02 TeV

2025/04/01 by ALICE Collaboration
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Nuclear Experiment (nucl-ex)

paper · doi:10.48550/arxiv.2504.00714

Abstract

The first measurement of prompt D^*+-meson spin alignment in ultrarelativistic heavy-ion collisions with respect to the direction orthogonal to the reaction plane is presented. The spin alignment is quantified by measuring the element ρ₀₀ of the diagonal spin-density matrix for prompt D^*+ mesons with 41/3 has been found for p_{\rm T}>15 GeV/c and 0.3<|y|<0.8 with a significance of 3.1σ. The measured spin alignment of prompt D^*+ mesons is compared with the one of inclusive J/ψ mesons measured at forward rapidity (2.5 < y < 4).

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