Type
Text
Type
Dissertation
Advisor
Qiu, Jian-Wei | Sterman, George | Deshpande, Abhay | Weinacht, Thomas | Morrison, David.
Date
2014-12-01
Keywords
factorization, fragmentation, Heavy quarkonium, QCD | Nuclear physics
Department
Department of Physics.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76745
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
From the Tevatron and the LHC data, it is clear that current models for the heavy quarkonium production are not able to explain the polarization of produced heavy quarkonia at large transverse momentum pT. A new approach to evaluate the heavy quarkonium production, by expanding the cross section in powers of 1/pT before the expansion in powers of &alphas, was proposed recently. In terms of the QCD factorization, it is proved that both the leading and next-to-leading power terms in 1/pT for the cross sections can be systematically factorized to all orders in powers of &alphas. The predictive power of this new QCD factorization formalism depends on several unknown but universal fragmentation functions (FFs) at an input scale of the order of heavy quarkonium mass mQ. These FFs should be extracted from the data in principle. However, fitting so many unknown multi-variable functions from the data is formidable practically. The lack of knowledge of the input FFs impedes the application of the QCD factorization. In this dissertation, inspired by the fact that these input FFs depend on mQ >> LambdaQCD<\sub>, we apply the NRQCD factorization formalism to further separate the perturbative and non-perturbative interactions. With our calculations, all the input unpolarized FFs are expressed as complicated functions with a few unknown NRQCD long-distance matrix elements (LDMEs). In addition, by general symmetry arguments, we successfully generalize the polarized NRQCD four-fermion operators to d dimensions and calculate the polarized FFs with conventional dimensional regularization. In the first application of the QCD factorization to unpolarized J/psi production, we find those NRQCD channels, which are expected to be important in the J/psi polarization, are actually dominated by the next-to-leading-power term in the pT expansion at current collider energies. Therefore the QCD factorization is very promising to solve the long standing heavy quarkonium polarization puzzle. | 181 pages
Recommended Citation
Zhang, Hong, "QCD factorization for heavy quarkonium production and fragmentation functions" (2014). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2626.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2626