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Problem formulation 2. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD

Simulation of Diffraction Dissociation in Various Models V. Uzhinsky, 27.11.13. Problem formulation 2. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD Diquark fragmentation functions Conclusion Consideration. 1. FTF results. Problem formulation.

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Problem formulation 2. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD

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  1. Simulation of Diffraction Dissociation in Various ModelsV. Uzhinsky, 27.11.13 • Problem formulation • 2. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD • Diquark fragmentation functions • Conclusion • Consideration 1 FTF results

  2. Problem formulation V. Uzhinsky, arXiv: 1308.0736 [hep-ph] FTF 9.6, pp-interactions UrQMD 3.3, pp-interactions NA61/SHINE exp. data 2

  3. Problem formulation Fritiof 1.6, Fritiof 7.0, Hijing, UrQMD 3.3, pp-interactions NA61/SHINE exp. data 3

  4. Problem formulation Fritiof 1.6, Fritiof 7.0, Hijing, UrQMD 3.3, pp-interactions NA49 exp. data 4

  5. Questions: What is wrong? Diffraction? Production? Fragmentation? Other processes? Problem formulation UrQMD takes into account the following processes 5

  6. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 Fritiof 1.6: Md=1.2 GeV, Pt=0.283 GeV/c Fritiof 7.0: Md=1.2 GeV, Pt=0.1 GeV/c UrQMD: Md=1.46 GeV, Pt=1.6 GeV/c Fritiof 7.0, diffraction: p+p -> p+g+q+qq -> p+Δ+(1232) 6

  7. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 p+p -> p+(n+Pi+) No “resonance” at M=1440 MeV. It is not Roper resonance. 7

  8. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 p+p -> n+(p+Pi+) UrQMD: No Δ(1232) at high energies! FTF – background. 8

  9. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 High energies. Ecms=23.77 GeV Step-like UrQMD distributions! UrQMD O.K. for high masses. FTF underestimates Xs. 9

  10. Diffraction in Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 Fritiof and UrQMD Fritiof 1.6 Exp. Data: K. Goulianos and J. Montanha, Phys. Rev. D59 (1999) 114017 Conclusion: Low mass diffraction is wrong in Fritiof-based models. No “resonance” at M=1440 MeV. FTF model: High mass – O.K., Low mass – No! 10

  11. Diquark fragmentation functions, UrQMD 3.3 11

  12. Diquark fragmentation functions, Fritiof 1.6 MST(10)=0 ! leading diquark always treated like a unit. 12

  13. Diquark fragmentation functions, FTF-Geant4 G4LundStringFragmentation.cc, GetLightConeZ G4double alund; if(std::abs(PDGEncodingOfDecayParton) < 1000) { // ---------------- Quark fragmentation ---------------------- alund=0.35/GeV/GeV; // Instead of 0.7 because kinks are not considered G4double zOfMaxyf=alund*Mt2/(alund*Mt2 + 1.); G4double maxYf=(1-zOfMaxyf)/zOfMaxyf * std::exp(-alund*Mt2/zOfMaxyf); G4double z, yf; do { z = zmin + G4UniformRand()*(zmax-zmin); // yf = std::pow(1. - z, blund)/z*std::exp(-alund*Mt2/z); yf = (1-z)/z * std::exp(-alund*Mt2/z); } while (G4UniformRand()*maxYf > yf); return z; } else { // ---------------- Di-quark fragmentation ---------------------- alund=0.7/GeV/GeV; // 0.7 2.0 G4double z, yf; do { z = zmin + G4UniformRand()*(zmax-zmin); yf = sqr(z-zmin)*(z-zmin)/sqr(zmax-zmin)/(zmax-zmin); } while (G4UniformRand() > yf); return z; } 13

  14. Diquark fragmentation functions, FTF-Geant4 14

  15. Conclusion • I am happy that I have found needed line to change in FTF. • A new fine tuning of FTF parameters is needed. 3. Low mass diffraction is not simulated correctly in all Fritiof-based models. 4. “Resonance” at M=1440 MeV has to be included in FTF. There are analogous “resonances” in Pi+P and K+P interactions. 5. Diffraction on nuclei can be re-considered now. Consideration One Pion Exchange Model

  16. Consideration One Pion Exchange Model S.D. Drell and K. Hiida, Phys. Rev. Lett. 7 (1961)199. R. Deck, Phys. Rev. Lett. 13 (1964) 1969. p+p -> p+(n+Pi+) For FTF How will be changed the diagrams and results in the case of hA interactions? C. Alvear, A.C.B. Antunes, Nuclear Physics A 615 (1997) 537 A. Bujak et al., Phys. Rev. D23 (1981) 1911. 16

  17. Diffraction on nuclei NA49 exp. data 17

  18. Consideration Diffraction at LHC Totem experiment: P+P -> P+P* -> P+N+ Pi+ ??? Pi+ can be registered instead of P!? It can be in low mass diffraction. 18

  19. Conclusion • I am happy that I have found needed line to change in FTF. • A new fine tuning of FTF parameters is needed. 3. Low mass diffraction is not simulated correctly in all Fritiof-based models. 4. “Resonance” at M=1440 MeV has to be included in FTF. There are analogous “resonances” in Pi+P and K+P interactions. 5. Diffraction on nuclei can be re-considered now. 19

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