Updated Blessed Plots for the Single Diffractive Dijet Analysis at
sqrt{s}=630 GeV
Contact person: Ken Hatakeyama (hatake@fnal.gov)
Date Blessed: 11 March 1999
CDF Note Number(s):
4895
Abstract
We have observed diffractive dijet production associated
with a leading antiproton in the Run 1C 630 GeV data obtained
with the roman-pot trigger.
Using the diffractive dijet events in the kinematic region of
the momentum loss fraction of the antiproton $0.04 < \xi < 0.10$
and the four momentum transfer squared $|t| < 0.2 \mbox{GeV}^2$,
we find that the cross section ratio of diffractive to non-diffractive
dijet events as a function of the momentum fraction of the parton
in the antiproton participating in the dijet production $x_{\Pbar}$
decreases with increasing $x_{\Pbar}$.
Comparisons are made with results obtained at $\sqrt{s}=1800$ GeV.
Kinematical Characteristics of Diffractive Dijets
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pot630_dijet_cmpnd_et07.ps--- Comparison of the leading and 2nd jet
$E_T$ distributions between diffractive and non-diffractive events.
-
pot630_dijet_cmpnd_etaphi07.ps--- Comaprison of the dijet mean
$\eta$ and $\Delta\phi$ (azimuthal angle between the leading two jets)
distributions between diffractive and non-diffractive events.
Ratio(SD/ND) versus $x_{pbar}$
-
pot630_xpbar_rsdnd_et07.eps--- The ratio of diffractive
to non-diffractive dijet cross sections as a function of $x_{pbar}$,
the momentum fraction of the parton in the antiproton participating
in the dijet production.
The jets with $E_T$ larger than 7 GeV are used.
-
pot1800_xpbar_rsdnd_et07.eps--- The same plot for the 1800 GeV
data.
Blessed Plots for the Single Diffraction Analysis at
sqrt{s}=630 GeV
Contact person: Ken Hatakeyama (hatake@fnal.gov)
Date Blessed: 12 February 1998
CDF Note Number(s):
4468
Abstract
During CDF Run 1C, we took roman-pot trigger data at both
sqrt{s}= 630 GeV and 1800 GeV.
The study of sqrt{s}=630 GeV roman-pot trigger data is
described on this page.
The 630 GeV roman-pot trigger data shows characteristics of
single diffractive dissociation.
The diffractive dijets are selected with 2nd jet
$E_T$ > 7 GeV.
The dijet events have low multiplicity on the antiproton(west)
side, and the dijet system is boosted to the proton(east) side.
The $E_T$ spectra of leading two jets are similar to
those in non-diffractive events, but slightly steeper.
The mean eta of dijets is shifted away from the pot tracks and
the distribution of phi difference between leading two jets is
slightly narrower in diffractive events.
The fraction of pot-track events with dijets above 7 GeV is
0.16 times the fraction in minimum bias events (statistical
errors about 4\%).
Single Diffractive Dissociation @ 630 GeV
-
pot630_eff_xit_box.ps--- Roman-pot efficiency in $\xi-t$ space,
during 630 GeV run. Due to the geometrical limit of roman-pot
detectors, we see only limited regions of $\xi$ and t.
-
pot630_xi_t.ps--- $\xi$ and $t$ distributions
in diffractive inclusive events. Solid line shows data and dashed line
shows the roman-pot simulation.
-
pot630_bbc_ntower_west.ps---
Forward detector response on west (antiproton) side.
We clearly see the low multiplicity signals on this side.
BBC covers the $\eta$ region (3.2 < |$\eta$| < 5.9),
and calorimeter multiplicity "Ntower" is counted in the region
(2.0 < |$\eta$| < 4.2). Finally, BBC multiplicity <= 6
cut is applied in order to remove the non-diffractive background.
-
pot630_bbc_ntower_east.ps--- Forward detector response
on east (proton) side.
Single Diffractive Dijets @ 630 GeV
-
pot630_dijet_et_eta_phi.ps---
Comparison of diffractive dijets with non-diffractive dijets.
Dijet events are selected with 2nd jet $E_T$ > 7 GeV.
The top two plots show the leading two jets' $E_T$
distributions.
Bottom left plot shows the dijet mean-$\eta$ distribution
and bottom right plot shows the $\Delta\phi$ distribution.
The $E_T$ spectra of the leading two jets are similar to those
in non-diffractive events, but slightly steeper.
The dijet mean-$\eta$ is boosted away from the pot tracks.
The $\Delta\phi$ distribution is slightly narrower.
-
pot630_xit_incl_dijet.ps--- Comparison of dijet to
inclusive $\xi$ and $t$ distributions. The left side plots show the
$\xi$ and $t$ distributions for diffractive dijet events(solid line) and
diffractive inclusive events(square points). The right side
plots show the
(diffractive_dijet - diffractive_inclusive)/(diffractive_inclusive)
as functions of $\xi$ and $t$.
-
pot630_bbc_ntower_dijet7.ps--- Forward detector response
in diffractive dijet events with 2nd jet $E_T$ > 7 GeV.
We clearly see the low multiplicity signals only on the
west(antiproton) side.
Finally, BBC multiplicity <= 6 cut is applied in order to
remove the non-diffractive background.
-
pot630_bbc_ntower_dijet10.ps--- Forward detector response
in diffractive dijet events with 2nd jet $E_T$ > 10 GeV.
Last updated April 7, 1999
Questions or suggestions? Please contact
hatake@fnal.gov