{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/bayesian-parameter-estimation-for","title":"Bayesian parameter estimation for relativistic heavy-ion collisions","arxiv_id":"1804.06469","date":"2018-04-17","proceeding":null,"authors":["Jonah E. Bernhard"],"abstract":"I develop and apply a Bayesian method for quantitatively estimating properties of the quark-gluon plasma (QGP), an extremely hot and dense state of fluid-like matter created in relativistic heavy-ion collisions. The QGP cannot be directly observed -- it is extraordinarily tiny and ephemeral, about $10^{-14}$ meters in size and living $10^{-23}$ seconds before freezing into discrete particles -- but it can be indirectly characterized by matching the output of a computational collision model to experimental observations. The model, which takes the QGP properties of interest as input parameters, is calibrated to fit the experimental data, thereby extracting a posterior probability distribution for the parameters. In this dissertation, I construct a specific computational model of heavy-ion collisions and formulate the Bayesian parameter estimation method, which is based on general statistical techniques. I then apply these tools to estimate fundamental QGP properties, including its key transport coefficients and characteristics of the initial state of heavy-ion collisions. Perhaps most notably, I report the most precise estimate to date of the temperature-dependent specific shear viscosity $\\eta/s$, the measurement of which is a primary goal of heavy-ion physics. The estimated minimum value is $\\eta/s = 0.085_{-0.025}^{+0.026}$ (posterior median and 90% uncertainty), remarkably close to the conjectured lower bound of $1/4\\pi \\simeq 0.08$. The analysis also shows that $\\eta/s$ likely increases slowly as a function of temperature. Other estimated quantities include the temperature-dependent bulk viscosity $\\zeta/s$, the scaling of initial state entropy deposition, and the duration of the pre-equilibrium stage that precedes QGP formation.","url_abs":"http://arxiv.org/abs/1804.06469v1","url_pdf":"http://arxiv.org/pdf/1804.06469v1.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"bayesian-parameter-estimation-for","repo_url":"https://github.com/jbernhard/hic-param-est","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}