Measurement of the Antiquark Flavor Asymmetry in the Nucleon Sea

Thesis/Dissertation · Tue May 01 04:00:00 EDT 2001

DOI:https://doi.org/10.2172/1421416· OSTI ID:1421416

Towell, Rusty Shane ^[1]

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1. Texas U.

A precise measurement of the ratio of Drell-Yan yields from an 800 GeV/c pro- ton beam incident on liquid hydrogen and deuterium targets is reported. Over 370,000 Drell-Yan muon pairs were recorded. From these data, the ratio of anti- down ($$\bar{d}$$) to anti-up ($$\bar{u}$$) quark distributions in the proton sea is determined over a wide range in Bjorken - $$x$$. A strong $$x$$ dependence is observed in the ratio $$\bar{d}$$ = $$\bar{u}$$. From this result, the integral of ($$\bar{d} - \bar{u}$$) is evaluated for 0.015 < $$x$$ < 0.35 and compared with deep inelastic scattering results. The origin of this asymmetry is probably due to non-perturbative effects such as those contained in pion cloud models. This measurement has instigated new global fits since previous parameterizations of the proton could not accommodate this large asymmetry

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1421416
• Report Number(s): nucl-ex/0102012; FERMILAB-THESIS-1999-26; UMI-99-47415; 553420
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS