# Presentation: 102191

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

- Ana Carolina Assis Jesus
- UERJ

***Outline***
- Introduction
- Heavy Flavor Production
- Next Steps

## 1. Introduction Concepts on Diffractive Physics

- 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 )

**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.**

##          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) 

-          2)A diffractive reaction is characterized by a large, _rapidity gap_ in the final state (Again, this is not sufficient to characterize diffraction)

## 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.

- 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.

## Process/Topologies

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

- 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:

- Q

## 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.

- It is good to remind that the diffractive mass available in makes the extraction of heavy flavor physics.

## 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.

## 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 ****
- the transferred momentum between the proton beam and the scattered proton (**t**)
- the diffractive mass (**M****x**)
- the fraction of the momentum of the proton carried by the Pomeron (****)
- the fraction of the momentum of the proton carried by the scattered proton (**x****p**)

## 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 .

## (a) Continue to summarize the literature of the subject
(b) Try to define more specific interest for one subject of                  
            analysis:
			- Look for J/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. 

- (b) Try to define more specific interest for one subject of
-             analysis:
- 			- Look for J/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.

- 3. Next Steps

- We intend to go on the following points:

## 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 *B**s** 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)