1 / 20

Strange Particles from NE X US 3

Fuming Liu Sergej Ostapchenko Tanguy Pierog Klaus Werner. hep-ph/0007198 Physics Reports 350 (2001) 93-289 hep-ph/0102194 Phys. Rev. Lett. 86 (2001) 3506. Hajo Drescher Michael Hladik. Joerg Aichelin Marcus Bleicher. SUBATECH , Nantes. Strange Particles from NE X US 3.

javier
Download Presentation

Strange Particles from NE X US 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fuming Liu Sergej Ostapchenko Tanguy Pierog Klaus Werner hep-ph/0007198 Physics Reports 350 (2001) 93-289 hep-ph/0102194 Phys. Rev. Lett. 86 (2001) 3506 Hajo Drescher Michael Hladik Joerg Aichelin Marcus Bleicher SUBATECH, Nantes Strange Particles from NEXUS 3 (Basic ideas, baryon production in pp) NEXUS 3 : Consistent treatment of multiple scattering

  2. Problems with the String Model Approach Particle production in pp scattering via string fragmentation Strings decay into chains of hadrons pp ==> 2 strings Not enough multiplicity fluctuations ==>

  3. Two Pairs of strings In general: n pairs of strings

  4. 2 / 2 Probability of n pairs ? Gribov Regge : Pomeron (= pair of strings) ...

  5. String model -- Gribov-Regge String model: first and subsequent pairs are of different nature Gribov-Regge: all Pomerons are identical String model: energy-momentum is properly shared among strings Gribov-Regge: energy-sharing is not considered inconsistent

  6. And …traditional string models fail badlywhen it comes to strange baryon production in pp ...

  7. The new approach Aim: connecting properly string model and Gribov-Regge Theory … and the parton model Extending work by Gribov, Kaidalov, Capella ...

  8. Basic Features Result of a pp collisions: 2 remnants and n Pomerons (all identical) Pomeron = 2 strings Energy-momentum properly shared Same formalism for particle production and probability calculations

  9. Notations Consider parton-parton scattering

  10. Amplitude: Squared amplitude => interference terms: Inelastic scattering in pp: remnant => Symbolic notation

  11. (Elastic and inelastic elem. Interactions) Inelastic scattering in AB: Squaring amplitude  sum over many interference terms expressed via cut and uncut elementary diagrams full energy conservation!! remnant Pomerons: multiplicity proportional to number of binary collisions Remnants: multiplicity proportional to participants

  12. Pomeron-Pomeron Interactions  • Diffraction • Screening • Shadowing • Saturation • Increasing mult. fluctuations • Solving F2-tot puzzle

  13. Hadronization Multiple scattering theory determines how many Pomerons are involved in each nucleon-nucleon interaction and the momenta of each Pomeron. Then: Pomeron  strings Strings  hadrons

  14. From Pomerons to Strings In the multiple scattering theory a dashed line represents a cut Pomeron The complicated hadronic structure is “hidden” What is the precise structure of a cut Pomeron? Pomeron = 2 strings

  15. pp scattering: 1 Pomeron 2 Pomerons etc Projectile remnant q, q-bar or qq qq-bar (sea quarks) strings Target remnant Crucial: separation of Pomerons and remnants otherwise completely wrong baryon yields (FM Liu, M Bleicher, J Aichelin, T. Pierog, KW et al)

  16. Baryon ratios in pp at 158 GeV 3 Traditional string models NEXUS: < 1

  17. Antibaryon/baryon ratios at RHIC (pp -1<y<1):NEXUS 3.97 STAR data (FM Liu, T.Pierog) (A.Billmeier):Proton: 0.834 +- 0.003 (0.81 +- ) Lambda: 0.950 +- 0.005 (0.89 +- 0.03)Xi: 0.98 +- 0.02 (0.97 +- 0.04) Omega: 0.99 +- 0.08 (0.90 +- 0.19)

  18. Why does the conventional string model give more antiomegas than omegas? A string end flavor u or d prevents the production of omegas NEXUS : projectile/target flavor is in the remnants not in the strings

  19. Baryon spectra in pp at 158 GeV Leading particles (mainly from remnants) Theory: NEXUS (FM Liu et al) Data: NA49

  20. Summary Consistent multiple scattering formalism => separation remnants - Pomerons (strings) => antibaryon/baryon ratios R < 1 contrary to conventional string models strings: R = 1 remnants: R < 1

More Related