Evidence of Spin-Orbital Angular Momentum Interactions in Relativistic Heavy-Ion Collisions


Acharya S., Adamová D., Adler A., Adolfsson J., Aggarwal M., Aglieri Rinella G., ...Daha Fazla

Physical Review Letters, cilt.125, sa.1, 2020 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 125 Sayı: 1
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1103/physrevlett.125.012301
  • Dergi Adı: Physical Review Letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MEDLINE, zbMATH, DIALNET
  • Yıldız Teknik Üniversitesi Adresli: Hayır

Özet

The first evidence of spin alignment of vector mesons (K∗0 and φ) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ρ00 is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at a center-of-mass energy (sNN) of 2.76 TeV with the ALICE detector. ρ00 values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum (pT<2 GeV/c) for K∗0 and φ at a level of 3σ and 2σ, respectively. No significant spin alignment is observed for the KS0 meson (spin=0) in Pb-Pb collisions and for the vector mesons in pp collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.