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Title: A Study of High Transverse Momentum Direct Photon Production in Interactions of 500 GeV/c $$\pi^{-}$$ and Proton Beams on a Beryllium Target

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/1372873· OSTI ID:1372873

This thesis presents the measurement of inclusive direct photon production cross section for experiment E706* for the data accumulated during 1987-88 fixed target run at Fermilab.$$^{\dagger}$$ The experiment employed a large liquid argon sampling calorimeter for electromagnetic particle detection with an energy resolution of approximately 15% $$\sqrt{E}$$. The spectrometer was exposed to incident $$\pi^-$$ and proton beam interacting with Beryllium (Be) target. The spectrometer triggered on high transverse momentum ($$P_{\tau}$$) electromagnetic showers. The incident $$\pi^-$$ beam was employed to measure the inclusive direct photon production cross sections from Be target in the $$P_{\tau}$$ range 3.5 < $$P_{\tau}$$ < 10 GeV/c. The incident proton beam was used to measure the inclusive direct photon production cross-sections from Be target in the $$P_{\tau}$$ range 4 < $$P_{\tau}$$ < 8 GeV/c. The cross sections are presented as a function of $$P_{\tau}$$ averaged over the rapidity ranges - .7 < y < - .2, - .2 < y < .2, .2 < y < .7 and - .7 < y < .7, as well as a function of rapidity integrated over $$P_{\tau}$$ range of 4 to 8 GeV/c. The ratio of direct photon production to $$\pi^0$$ production ($$\gamma/\pi^0$$ ) is also presented. The $$\gamma/\pi^0$$ ratio for $$\pi^-$$ and proton beam on Beryllium target is compared to leading log Quantum Chromodynarnics ( QCD) predictions. The direct photon cross sections are compared to next to leading log QCD predictions. Results are also compared to previous experiments.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
DOE Contract Number:
AC02-07CH11359
OSTI ID:
1372873
Report Number(s):
FERMILAB-THESIS-1991-38; RX-1411 (DELHI); 326664
Country of Publication:
United States
Language:
English