Diffractive Heavy Flavor Production (in proton X anti-proton collisions at 2TeV)

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Diffractive Heavy Flavor Production(in proton X
anti-proton collisions at 2TeV)

• Ana Carolina Assis Jesus
• UERJ

• Outline
• Introduction
• Heavy Flavor Production
• Next Steps

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1. Introduction Concepts on Diffractive Physics

• I intend to present a series of short talks to go
  to my Thesis subject
• following the progress of the work to be done.
  This is my first.

• The term diffraction was borrowed from optics
• So, diffraction suggests that the propagation and
  interaction of extended objects, such as hadrons,
  are due to the absorption of its wave functions,
  originated from the several inelastic channels
  that are opened when high energy is reached.
• In particle physics terminology a general
  definition of hadronic diffraction processes can
  be formulated as follows

Each point of a wave edge is a source of
spherical waves (Huygen-Fresnel )
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• 1) A reaction in which no quantum
  numbers are exchanged between the colliding
  particles is, at high energies, a diffraction
  reaction. (This is a necessary condition, but not
  a sufficient one). On the other hand, the big
  advantage of this definition its that it is
  simple and general enough to cover all cases
• 2)A diffractive reaction is
  characterized by a large, rapidity gap in the
  final state (Again, this is not sufficient to
  characterize diffraction)

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• The traditional theoretical framework for
  diffraction is Regge theory, that describes
  hadronic reactions at high energies in terms of
  the exchanged of objects called reggeon and
  this reggeon with vacuum quantum numbers which
  dominates asymptotically is the so-called Pomeron
  
• There are two different complementary methods to
  study diffractive production
• 1) The first is by searching for rapidity
  gaps, which are pseudo-rapidity regions (?)
  devoid of particles, in the event topology
• meaning the absence of colour activity
• 2) The other technique is the direct
  measurement of the diffractively scattered
  (anti)proton with the appropriate spectrometer.

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Process/Topologies

• We will only show hard diffraction process.
• Single Diffraction

Q

• Single diffractive events are those in which one
  of the colliding hadrons (proton or antiproton)
  exchange a Pomeron (P) . So, these reactions
  would correspond to

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• The rapidity gaps are presumed to be due to the
  exchange of a Pomeron ( ), which is a
  color-singlet state with vacuum quantum numbers.
• It is good to remind that the diffractive mass
  available in makes the extraction of heavy flavor
  physics.

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• Double Pomeron Exchange

• This process is studied through the jets
  production observed in the central detectors for
  events containing both, proton and anti-proton,
  identified in the appropriate spectrometers
  or/and a rapidity gap on each side of the
  detector.

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Kinematical Variables

• In the study of the diffractive physics it is
  important to know the behavior of the data with
  respect to some kinematics variables, such as
• the pseudo-rapidity (h)
• the transferred momentum between the proton beam
  and the scattered proton (t)
• the diffractive mass (Mx)
• the fraction of the momentum of the proton
  carried by the Pomeron (x)
• the fraction of the momentum of the proton
  carried by the scattered proton (xp)

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2. Diffractive Heavy Flavor Production

• The heavy quark production is made through the
  strong interactions between the constituents
  (partons) of the hadrons.
• The signature for particles of heavy flavors can
  be derived from the relatively large masses and
  of the weak nature of the decays.
• The heavy flavor physics has been extensively
  studied in high pT (QCD) without taking into
  account diffractive component of the production.
• For lack of adequate instrumentation, there are
  rare measurements of the cross sections with a
  separation of the diffractive and non diffractive
  events. It is expected that with the insertion of
  the low angles detectors, it will be possible to
  measure directly the cross sections of the
  diffractive production .

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3. Next Steps
We intend to go on the following points

• (a) Continue to summarize the literature of the
  subject
• (b) Try to define more specific interest for one
  subject of
• analysis
• - Look for J/Y diffractively produced and
  compare
• with the high pt
  production.
• - Look for b bar diffractively produced?
• - Any other topic? Suggestions are welcome!
• (c) Produce Monte Carlo Events (Pompyt? Any
  other?)
• (d) Define parameters for cuts.
• (e) AGAIN, suggestions are welcome.
• Thanks.

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References

• E. Predazzi High-Energy Particle Diffraction
• D0 Collaboration The bbbar production cross
  section and angular correlations in ppbar
  collisions at 1.8TeV Physics Letter B487 (2000)
  264-272
• M. Heyssler Diffractive Heavy Flavour Production
  at the Tevatron and the LHC (hep-ph/9602420)
• A. Santoro The Future of Diffraction at Tevatron
  (hep-ex/0011023)
• A. Solodsky Hard Diffractive at CDF
  FERMILAB-Conf-00/078-E
• P. Marage Hadronic structure, low x physics and
  diffraction (hep-ph/9911426)
• D. Lucchesi Bs Physics and Prospects at the
  Tevatron (hep-ex/0307025)
• T. Affolder at al., Measurement of b Quark
  Fragmentation Fractions in ppbar Collisions at
  sqrt(s) 1.8 TeV. Phys. Rev. Lett. 84, 1663
  (2000)