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

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/979709· OSTI ID:979709
 [1]
  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; TRN: US1003380
Country of Publication:
United States
Language:
English