https://doi.org/10.1140/epjc/s10052-019-7213-6
Regular Article - Theoretical Physics
Polarization transfer in hyperon decays and its effect in relativistic nuclear collisions
1
Dipartimento di Fisica, Università di Firenze, and INFN, Sezione di Firenze, Florence, Italy
2
School of Physics and Astronomy, Sun Yat-Sen University, Guangzhou, 510275, China
3
Institute for Theoretical Physics, Goethe University, 60438, Frankfurt am Main, Germany
* e-mail: becattini@fi.infn.it
Received:
20
May
2019
Accepted:
8
August
2019
Published online:
5
September
2019
We calculate the contribution to the polarization of hyperons in relativistic nuclear collisions at high energy from the decays of
and
, which are the predominant sources of
production besides the primary component, as a function of the
momentum. Particularly, we estimate the longitudinal component of the mean spin vector as a function of the azimuthal angle in the transverse plane, assuming that primary
and
polarization follow the predictions of local thermodynamic equilibrium in a relativistic fluid. Provided that the rapidity dependence around midrapidity of polarization is negligible, we find that this component of the overall spin vector has a very similar pattern to the primary one. Therefore, we conclude that the secondary decays cannot account for the discrepancy in sign between experimental data and hydrodynamic model predictions of the longitudinal polarization of
hyperons recently measured by the STAR experiment at RHIC.
© The Author(s), 2019