Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC
| dc.contributor.author | Blyth, Sarah-Louise | |
| dc.date.accessioned | 2024-06-19T10:14:30Z | |
| dc.date.available | 2024-06-19T10:14:30Z | |
| dc.date.issued | 2007 | |
| dc.date.updated | 2024-06-19T09:44:04Z | |
| dc.description.abstract | [pg 76 is missing] This thesis presents measurements of ¢-meson production and elliptic flow, 1,2, with the aim of probing the characteristics of the medium created in ultra-relativistic nucleus-nucleus collisions. Using the decay channel q;-+ K+ K-, high statistics measurements have been made for ¢-meson production at mid-rapidity in Au+Au collisions at ,.,jsim = 200 GeV using the STAR detector at RHIC. The ¢-meson invariant yields both integrated, and as a function of PT, are presented for a wide range of collision centralities. The transverse momentum distributions exhibit an evolution in shape with decreasing collision centrality from exponential-like to power-law-like, indicating a variation in the relative contributions from competing particle production mechanisms to ¢ production as a function of collision centrality. Measurements of the nuclear modification factor, Rep, for 0-5% central relative to 40-60% and 60-80% central collisions show that binary-scaled ¢-meson production is suppressed in central compared to more peripheral collisions. The baryon-meson scaling of Rep observed for other identified particles is also observed for the ¢-meson through its similarity to the K� Rep for 0-5%/40-60% ratio. The scaling appears to break down in the 0- 5%/60-80% case. The centrality dependence of the N ( 0) / N ( ¢) ratios are also presented. The central ratio is consistent up to Pr ;S 4 Ge V / c with expectations from a model in which multistrange hadrons are produced predominantly by recombination of thermal s quarks. In addition, the ¢-meson elliptic flow, v2 (pr ), has been measured in Au+Au collisions at ,.,fsim = 62.4 GeV and 200 GeV and is found to be similar for the two collision energies. The significant v2 for the ¢-meson, comparable to that of other particles, indicates significant rescattering of the medium constituents. In minimum bias collisions at 200 GeV, for PT < 2 GeV /c, the ¢-meson v2 is consistent with a mass ordering expected from hydrodynamics while for PT > 2 Ge V / c it is consistent with meson-scaling. This is strong evidence for partonic collectivity of the medium created in the collisions. First measurements of the centrality dependence of the ¢-meson integrated elliptic flow scaled by the eccentricity of the nuclear overlap region, (v2) / Epart, show an increasing trend with centrality and may indicate greater collectivity of the medium created in central compared to peripheral Au+Au collisions. | |
| dc.identifier.apacitation | Blyth, S. (2007). <i>Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC</i>. (). ,Faculty of Science ,Department of Physics. Retrieved from http://hdl.handle.net/11427/39976 | en_ZA |
| dc.identifier.chicagocitation | Blyth, Sarah-Louise. <i>"Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC."</i> ., ,Faculty of Science ,Department of Physics, 2007. http://hdl.handle.net/11427/39976 | en_ZA |
| dc.identifier.citation | Blyth, S. 2007. Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC. . ,Faculty of Science ,Department of Physics. http://hdl.handle.net/11427/39976 | en_ZA |
| dc.identifier.ris | TY - Thesis / Dissertation AU - Blyth, Sarah-Louise AB - [pg 76 is missing] This thesis presents measurements of ¢-meson production and elliptic flow, 1,2, with the aim of probing the characteristics of the medium created in ultra-relativistic nucleus-nucleus collisions. Using the decay channel q;-+ K+ K-, high statistics measurements have been made for ¢-meson production at mid-rapidity in Au+Au collisions at ,.,jsim = 200 GeV using the STAR detector at RHIC. The ¢-meson invariant yields both integrated, and as a function of PT, are presented for a wide range of collision centralities. The transverse momentum distributions exhibit an evolution in shape with decreasing collision centrality from exponential-like to power-law-like, indicating a variation in the relative contributions from competing particle production mechanisms to ¢ production as a function of collision centrality. Measurements of the nuclear modification factor, Rep, for 0-5% central relative to 40-60% and 60-80% central collisions show that binary-scaled ¢-meson production is suppressed in central compared to more peripheral collisions. The baryon-meson scaling of Rep observed for other identified particles is also observed for the ¢-meson through its similarity to the K� Rep for 0-5%/40-60% ratio. The scaling appears to break down in the 0- 5%/60-80% case. The centrality dependence of the N ( 0) / N ( ¢) ratios are also presented. The central ratio is consistent up to Pr ;S 4 Ge V / c with expectations from a model in which multistrange hadrons are produced predominantly by recombination of thermal s quarks. In addition, the ¢-meson elliptic flow, v2 (pr ), has been measured in Au+Au collisions at ,.,fsim = 62.4 GeV and 200 GeV and is found to be similar for the two collision energies. The significant v2 for the ¢-meson, comparable to that of other particles, indicates significant rescattering of the medium constituents. In minimum bias collisions at 200 GeV, for PT < 2 GeV /c, the ¢-meson v2 is consistent with a mass ordering expected from hydrodynamics while for PT > 2 Ge V / c it is consistent with meson-scaling. This is strong evidence for partonic collectivity of the medium created in the collisions. First measurements of the centrality dependence of the ¢-meson integrated elliptic flow scaled by the eccentricity of the nuclear overlap region, (v2) / Epart, show an increasing trend with centrality and may indicate greater collectivity of the medium created in central compared to peripheral Au+Au collisions. DA - 2007 DB - OpenUCT DP - University of Cape Town KW - Physics LK - https://open.uct.ac.za PY - 2007 T1 - Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC TI - Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC UR - http://hdl.handle.net/11427/39976 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/39976 | |
| dc.identifier.vancouvercitation | Blyth S. Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC. []. ,Faculty of Science ,Department of Physics, 2007 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/39976 | en_ZA |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Physics | |
| dc.publisher.faculty | Faculty of Science | |
| dc.subject | Physics | |
| dc.title | Using the ¢-meson to probe the medium created in Au+Au collisons at RHIC | |
| dc.type | Thesis / Dissertation | |
| dc.type.qualificationlevel | Doctoral | |
| dc.type.qualificationlevel | PhD |