The transversity distribution function, $h_1^{q}(x)$, where $x$ is the longitudinal momentum fraction of the proton carried by quark $q$, encodes the proton's transverse spin structure at leading twist. Difficulties arise when extracting $h_1^q(x)$ due to its chiral-odd nature. However, it can be coupled with a spin-dependent interference fragmentation function (FF), $H_1^{\sphericalangle, h_1h_2}$, in a dihadron ($h_1h_2$) production channel in polarized proton-proton ($p^\uparrow p$) collisions. The coupling of $h_1^{q}(x)$ and $H_1^{\sphericalangle, h_1h_2}$ produces an experimentally measurable azimuthal correlation asymmetry, $A_{UT}$, between the spin of the fragmenting quark and the final state dihadron. A model-independent extraction of transversity from these measurements relies on the knowledge of dihadron FFs, namely the unpolarized dihadron FFs, $D_1^{h_1h_2/q(g)}$ for quarks, \emph{q} (gluons, \emph{g}). Extraction of these FFs requires measurements of the unpolarized dihadron cross-section in $pp$ collisions, which are urgently needed. In $pp$ collisions, the unpolarized cross-section measurement provides access to the $D_1^{h_1h_2}$ for both quarks and gluons. This thesis outlines the measurements of the \dipion azimuthal correlation asymmetry in the forward ($\eta > 0$) and backward ($\eta < 0$) pseudorapidity regions with respect to the polarized beam using the RHIC Run 2015 polarized $pp$ data and the measurement of the unpolarized \dipion cross-section in the invariant mass bins in the mid-pseudorapidity ($|\eta|<1$) region using the RHIC Run 2012 $pp$ data at $\sqrt{s}=200$ GeV. These data sets were collected at the STAR experiment. The STAR Time Projection Chamber (TPC), Barrel Electromagnetic Calorimeter (BEMC), and Time-of-Flight Detector (TOF) were used in conjunction to measure outgoing particle energy, tracking, and identification. / Physics
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/9539 |
| Date | 08 1900 |
| Creators | Pokhrel, Babu Ram |
| Contributors | Surrow, Bernd, Metz, Andreas, Napolitano, Jim, Vossen, Anselm AV |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Text |
| Format | 236 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/9501, Theses and Dissertations |
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