We propose that a significant positive deviation from 1/3 for the spin density matrix element ρ00 of the φ meson may indicate the existence of a mean field of the φ meson generated in heavy-ion collisions. This explains why STAR preliminary data for the φ meson's ρ00 are much larger than 1/3, while the data of Λ and Λ¯ polarization seem not to allow such a significant and positive deviation. The contribution is from the polarization of the strange quark and antiquark through the spin-orbit interaction in the φ field, a similar interaction that is responsible for nuclear shell structure at the nucleon level. We show that ρ00 for the φ meson is a good analyzer for fields even if they may strongly fluctuate in space-time.
What can we learn from the global spin alignment of φ mesons in heavy-ion collisions?
Oliva L.;
2020-01-01
Abstract
We propose that a significant positive deviation from 1/3 for the spin density matrix element ρ00 of the φ meson may indicate the existence of a mean field of the φ meson generated in heavy-ion collisions. This explains why STAR preliminary data for the φ meson's ρ00 are much larger than 1/3, while the data of Λ and Λ¯ polarization seem not to allow such a significant and positive deviation. The contribution is from the polarization of the strange quark and antiquark through the spin-orbit interaction in the φ field, a similar interaction that is responsible for nuclear shell structure at the nucleon level. We show that ρ00 for the φ meson is a good analyzer for fields even if they may strongly fluctuate in space-time.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
