TY  - JOUR
A1  - Rose, Jean-Bernard
A1  - Torres-Rincon, Juan M.
A1  - Elfner, Hannah
T1  - Inclusive and effective bulk viscosities in the hadron gas
T2  - Journal of physics. G
N2  - We estimate the temperature dependence of the bulk viscosity in a relativistic hadron gas. Employing the Green–Kubo formalism in the SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) transport approach, we study different hadronic systems in increasing order of complexity. We analyze the (in)validity of the single exponential relaxation ansatz for the bulk-channel correlation function and the strong influence of the resonances and their lifetimes. We discuss the difference between the inclusive bulk viscosity of an equilibrated, long-lived system, and the effective bulk viscosity of a short-lived mixture like the hadronic phase of relativistic heavy-ion collisions, where the processes whose inverse relaxation rate are larger than the fireball duration are excluded from the analysis. This clarifies the differences between previous approaches which computed the bulk viscosity including/excluding the very slow processes in the hadron gas. We compare our final results with previous hadron gas calculations and confirm a decreasing trend of the inclusive bulk viscosity over entropy density as temperature increases, whereas the effective bulk viscosity to entropy ratio, while being lower than the inclusive one, shows no strong dependence to temperature.
KW  - hadron gas
KW  - bulk viscosity
KW  - Monte-Carlo simulations
KW  - heavy-ion collisions
Y1  - 2020
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/63181
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-631810
SN  - 1361-6471
SN  - 0954-3899
N1  - Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project number 315477589—TRR 211.
N1  - This work was supported by the Helmholtz International Center for the Facility for Antiproton and Ion Research (HIC for FAIR) within the framework of the Landes-Offensive zur Entwicklung Wissenschaftlich-Oekonomischer Exzellenz (LOEWE) program launched by the State of Hesse.
VL  - 48
IS  - art. 015005
SP  - 1
EP  - 31
PB  - IOP Publ.
CY  - Bristol
ER  -