Search for Randall-Sundrum Gravitons in Dielectron and Diphoton Final States with 5.4fb^-1 of DØ Data

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 2010

DOI:https://doi.org/10.2172/979709· OSTI ID:979709

Zhou, Ning ^[1]

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1. Columbia Univ., New York, NY (United States)

A search for the lightest Kaluza-Klein mode of the graviton in the Randall-Sundrum model with a warped extra dimension is performed in the dielectron and diphoton channels. The data set used for the search corresponds to 5.4 fb^-1 of data from p$$\bar{p}$$ collisions at a center-of-mass energy of 1.96 TeV, collected with the D0 detector at the Fermilab Tevatron between July 2002 and Summer 2009. We search for resonances in the invariant mass spectrum of two electromagnetic showers from the decay of the graviton to either electron-positron pairs or photon pairs. To optimize the sensitivity, the dielectron and diphoton channels are analyzed separately, then the results are combined together in the end. We also investigate whether, due to the unique spin-2 nature of the graviton, the angular distribution of the final state particles can be used to significantly enhance the sensitivity of the search. We set 95% confidence level upper limits on the graviton production cross section times branching fraction into electron-positron pairs of between ~ 7 fb and ~ 0.5 fb for a range of graviton masses from 220 GeV and 1050 GeV, respectively. Compared with Randall-Sundrum model predictions, these results correspond to lower limits on the lightest graviton mass between 440 GeV and 1040 GeV, for the dimensionless graviton coupling to the Standard Model fields k/$$\bar{M}$$_Pl in the range from 0.01 to 0.1. In addition, for coupling k/$$\bar{M}$$_Pl of 0.01, gravitons with masses between 460 GeV and 560 GeV are also excluded at 95% confidence level. These results represent the most sensitive limits to date.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 979709
• Report Number(s): FERMILAB-THESIS--2010-14
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR DISTRIBUTION
CROSS SECTIONS
DECAY
DIMENSIONS
Experiment-HEP
FERMILAB TEVATRON
GRAVITONS
PHOTONS
PRODUCTION
SENSITIVITY
STANDARD MODEL