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 4 < pT < 30 GeV/c in two rapidity intervals, |y| < 0.3 and 0.3 < |y| < 0.8, in central (0–10%) and midcentral (30–50%) Pb–Pb collisions at √ sNN = 5.02 TeV. Evidence of spin alignment ρ00 > 1/3 has been found for pT > 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).

Acharya, S., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., Agrawal, N., et al. (2025). First measurement of D*+ vector meson spin alignment in Pb–Pb collisions at √sNN = 5.02 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2025(10), 1-26 [10.1007/JHEP10(2025)094].

First measurement of D*+ vector meson spin alignment in Pb–Pb collisions at √sNN = 5.02 TeV

Agrawal N.;Alici A.;Arcelli S.;Bellini F.;Colocci M.;Ercolessi F.;Jacazio N.;Malfattore G.;Romanenko G.;Rubini N.;Sabiu B.;Scioli G.;Strazzi S.;Tomassini S.;
2025

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 4 < pT < 30 GeV/c in two rapidity intervals, |y| < 0.3 and 0.3 < |y| < 0.8, in central (0–10%) and midcentral (30–50%) Pb–Pb collisions at √ sNN = 5.02 TeV. Evidence of spin alignment ρ00 > 1/3 has been found for pT > 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).
2025
Acharya, S., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., Agrawal, N., et al. (2025). First measurement of D*+ vector meson spin alignment in Pb–Pb collisions at √sNN = 5.02 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2025(10), 1-26 [10.1007/JHEP10(2025)094].
Acharya, S.; Agarwal, A.; Aglieri Rinella, G.; Aglietta, L.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Ahuja, I.; Akindinov, A.; A...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1048770
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