Electron positron pair production in ultraperipheral Au+Au collisions at RHIC
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Authors
Rehbein, Matthew
Issue Date
2017-07-27
Volume
Issue
Type
Thesis
Language
en_US
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Abstract
This thesis presents a measurement of the cross section for coherent production of electron-positron pairs in ultraperipheral collisions of gold ions with a center-of-mass energy of 200 GeV per nucleon. The collisions were observed in runs 10 and 11 at the Relativistic Heavy Ion Collider (RHIC), using the Solenoidal Tracker at RHIC (STAR detector).|Ultraperipheral collisions occur when the distance of closest approach between the centers of two nuclei is slightly larger than the sum of the two nuclear radii. Because hadronic interactions are suppressed in ultraperipheral collisions, this process is purely electromagnetic. The large charge (Z=79 for each nucleus) and short separation distance in this interaction results in the overlap of two very strong electromagnetic fields in the space between the nuclei. The photons comprising these fields can interact to produce matter/antimatter pairs, including electrons and positrons.|This thesis includes an introduction to the relevant physics concepts, a detailed description of the structure and function of the STAR detector, and an explanation of how the electron-positron signal is extracted from the collected dataset. The calculation of the measured differential cross section is also given with respect to the invariant mass, transverse momentum, and rapidity of the pairs, and these measured values are compared to theoretical predictions.
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Publisher
Creighton University
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Copyright is retained by the Author. A non-exclusive distribution right is granted to Creighton University and to ProQuest following the publishing model selected above.