dc.contributor.advisor Stevenson, Paul M. Caveny, Scott Andrew 2009-06-04T08:30:42Z 2009-06-04T08:30:42Z 1998 https://hdl.handle.net/1911/17158 We find evidence for an infrared fixed point in perturbative QCD using two complementary approximations: The Banks-Zaks expansion and the large-b resummations. Analyzing the $e\sp+e\sp-$ annihilation ratio and the polarized Bjorken-sum-rule of deep-inelastic-scattering, we use the recent calculation of the renormalization-group $\beta$-function to four-loops in QCD to confirm that the Banks-Zaks expansion is relevant when extrapolated from sixteen down to two light quark flavors. We also search for indications of infrared 'freezing' in the Borel-renormalon-inspired 'large-b' resummations. We find the 'large-b' approximation also indicates perturbative 'freezing' of the $e\sp+e\sp-$ annihilation ratio and the polarized Bjorken-sum-rule at leading order. Finally, we study the region, $n\sb{f}$ = 2, where the 'large-$n\sb{f}$' resummation and Banks-Zaks expansion complement one another. We conclude that there is strong evidence for the existence of a perturbative infrared fixed point in the Standard Model QCD. 96 p. application/pdf eng Particle physicsElementary particlesHigh energy physics 'Freezing' in perturbative quantum chromodynamics: The Banks-Zaks expansion and leading-b resummations Thesis Text Physics Natural Sciences Rice University Masters Master of Arts Caveny, Scott Andrew. "'Freezing' in perturbative quantum chromodynamics: The Banks-Zaks expansion and leading-b resummations." (1998) Master’s Thesis, Rice University. https://hdl.handle.net/1911/17158.
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