Kinematic Study of Diffractive Dijet Events @ 1.8TeV

Contact person: Hosai Nakada (hosai@fnald.fnal.gov)
Date Blessed: 12 February 1998
CDF Note Number(s): 4403

Abstract

We study the kinematics of events with a Roman-pot~(RP) track with $x_F > 0.9$ and two central jets in 1.8 TeV Run-1C data. The Roman-pot tags recoil $\bar{p}$ and its acceptance corresponds to a fractional momentum loss $\xi$ from 4\% to 9.5\% and the absolute value of the four-momentum transfer squared $|t|$ less than 1 GeV$^2$. We compared several kinematical variables($E_T,\eta_{Jet},\Delta\phi$...etc.) of such Pot-Dijet (PJJ) events to those of Dijet events in typical non-diffractive collisions (JJ). We see clear differences between PJJ events and JJ events in the distributions of $\eta_{Jets}$, rapidity of dijet system, and azimuthal opening angle between the leading two jets~($\Delta\phi$). On the other hand, the $E_T$ spectra of the leading two jets are very similar.

Plots

Plot 1-- The leading jet $E_{T}$ spectra for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle). The top right plot shows (diffractive dijet - non-diffractive dijet)/(non-diffractive dijet) as a function of leading jet $E_{T}$.

Plot 2-- The next-to-leading jet $E_{T}$ spectra for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle). The top right plot shows (diffractive dijet - non-diffractive dijet)/(non-diffractive dijet) as a function of next-to-leading jet $E_{T}$.

Plot 3-- The 3rd jet $E_{T}$ spectra for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle). The top right plot shows (diffractive dijet - non-diffractive dijet)/(non-diffractive dijet) as a function of thrid jet $E_{T}$.

Plot 4-- The $\eta$ distributions of the leading three jets for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle).

Plot 5-- The distributions of the rapidity of the dijet system for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle).

Plot 6-- The $\Delta\phi_{jj}$ distributions for the diffractive dijet sample (points) and the non-diffractive dijet sample (open triangle). The top plot shows in case of linear scale in vertical axis, the bottom is in case of log scale.