CDF Logo Analysis of High Mass Di-Photon Events and Search for Randall-Sundrum Gravitons Exotics Logo

This Run II analysis searches for high mass di-photon states. We examine the di-photon dataset (Triggers: diphoton E_T > 12 or 18 GeV, and photon E_T > 50 or 70) requiring either two central photons or one central and one plug photon, both with E_T > 15 GeV. We examine events with an invariant mass greater than 30 GeV/c^2. The mass spectrum of the di-photon events is binned according to detector resolution and compared to background expectations. Standard Model di-photon production is estimated with the diphox NLO Monte Carlo program. Non-photon contribution, jets misidentified as photons, is estimated from the data via a sideband method. The total a prioribackground compares well to the data. The limits are determined by a fit to the signal mass distribution.

The search for new particles decaying to di-photon final states uses the Randall-Sundrum model to express sensitivity to Kaluza-Klein graviton resonances. Such resonances are narrower than the CDF detector resolution.



Blessed Plots and Tables:

Diphoton invariant mass distribution:
Di-photon invariant mass plot, in variable bin widths with bin widths comparable to the mass resolution.
Central-Central and Central-Plug EPS or GIF.
Total EPS or GIF.

Comparison of data with background expectations:
Comparison of Standard Model di-photon contribution plus misidentified jets with observed data, 5 GeV/c^2 mass bins. This background estimate is not usd in setting limits.
Central-Central and Central-Plug EPS or GIF.
All data EPS or GIF.

Acceptance and Efficiency:
Total acceptance of Randall-Sundrum gravitons as function of graviton mass, EPS or GIF.
Total efficiency of Randall-Sundrum gravitons as function of graviton mass, EPS or GIF.
Total efficiency: Central photons, EPS or GIF.
Total efficiency: Plug photons, EPS or GIF.

Cross-section, mass, and combined RS graviton limits:
Fit to the mass spectra which are used to set the background level for setting limits for central-central and central-plug EPS or GIF.
95% confidence level RS graviton cross-section times branching ratio limits as function of graviton mass, with & without systematics:
central-central EPS or GIF.
central-plug EPS or GIF.
combined EPS or GIF.
95% confidence level RS graviton cross-section times branching ratio limits as function of graviton mass, EPS or GIF.
95% confidence level RS graviton mass limits in the graviton mass versus coupling, k/M_Planck, plane, EPS. GIF.
Table of limits JPG GIF. Latex

Highest Mass Events

Event display of the highest mass central-central diphoton event, 602 GeV/c^2:
COT view, EPS, GIF
Lego view, EPS, GIF

Event display of the highest mass central-plug diphoton event, 454 GeV/c^2:
COT view, EPS, GIF
Lego view, EPS, GIF

Diphoton limits combined with di-electron limits
Combined 95% confidence level RS graviton mass limits of the di-photon and di-lepton searches vs graviton mass. GIF.
Combined 95% confidence level RS graviton mass limits of the di-photon and di-lepton searches in the graviton mass versus coupling, k/M_Planck, plane, GIF.



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