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Probing non-standard top-gluon couplings at hadron colliders

Based on EPJC 65 (2010) 127 [ arXiv:0910.3049 ]. Probing non-standard top-gluon couplings at hadron colliders. Introduction Framework Non-standard top-gluon couplings Analyses Constrains from Tevatron data Application to LHC experiment Summary.

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Probing non-standard top-gluon couplings at hadron colliders

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  1. Based on EPJC 65 (2010) 127 [ arXiv:0910.3049] Probing non-standard top-gluon couplings at hadron colliders • Introduction • Framework • Non-standard top-gluon couplings • Analyses • Constrains from Tevatron data • Application to LHC experiment • Summary K. Ohkuma（Fukui Tech.） Z. Hioki（Tokushima Univ.） KEK Theory Meeting on Particle Physics Phenomenology. Feb. 2010@KEK

  2. I. Introduction

  3. Ⅰ Ⅱ Ⅲ Ⅳ Introduction • The Standard Model • Highly successful model • Phenomenological prediction and description • Not perfect model • Many parameters • Hierarch problems • Neutrino mass • Mechanism of mass generation Seek Post Standard Model Probing non-standard top-gluon couplings at hadron colliders

  4. Ⅰ Ⅱ Ⅲ Ⅳ Complementarity relation Introduction • How to seek post standard model • Model dependent approach • SUSY, Little Higgs，Extra Dimensionetc. → Select new models from experiment • Model independent approach • Most general couplings for interactions 　　→ Select extension of new couplings from experiment Collider experiments are important Probing non-standard top-gluon couplings at hadron colliders

  5. Ⅰ Ⅱ Ⅲ Ⅳ Introduction • New physics signature at collider experiment New Physics search Direct Search Indirect Search • Direct detection of new particles 　 → Clear evidence • Deviations from the SM via quantum effect of new physics 　 → Precise measurements • u, d, s, c →no deviation • b, t →no deviation ? Probing non-standard top-gluon couplings at hadron colliders

  6. Ⅰ Ⅱ Ⅲ Ⅳ Lepton Gaugeboson Quark Introduction • Discovered in 1994 • Newest particle • About 175 GeV mass • Heaviest particle • Largest interaction with Higgs • Measured at CDF and D0 • Tevatron is unique machine → LHC will measure Top firstly except for Tevatron • Top quark H Probing non-standard top-gluon couplings at hadron colliders

  7. Ⅰ Ⅱ Ⅲ Ⅳ Focus on top-gluon couplings Introduction • Top quark physics(From Tevatron to LHC) －　Top pair production TevatronProton－Anti-Proton collider LHCProton－　 Proton collider Subprocesses( In SM) Tev. ＞ LHC Tev. ＜ LHC Probing non-standard top-gluon couplings at hadron colliders

  8. Ⅰ Ⅱ Ⅲ Ⅳ Introduction • Aims • Try to expand the top-gluon couplings as model-independent as possible → Effective Lagrangian Approach • Estimate observabilities of effects from non-standard top-gloun couplings at LHC • Constraints non-standard top-gluons couplings from Tevatron data → Experimental data vs Theoretical prediction • Observabilities of non-standard top-gluon couplings at LHC → Deviations from SM prediction Probing non-standard top-gluon couplings at hadron colliders

  9. II. Framework

  10. Ⅰ Ⅱ Ⅲ Ⅳ Framework • Assumption • All non-standard particles are heavier than the lowest new physics scale in the low energy processes • non-standard particles are decupled • only standard particles are appeared → Deviations from SM prediction with High precision　⇔ Observation of Effective Operator c.f. Fermi interaction Probing non-standard top-gluon couplings at hadron colliders

  11. Ⅰ Ⅱ Ⅲ Ⅳ SU(3) X SU(2) X U(1) gauge invariant dim.6 operator Non-standard coupling Scale of new physics The SM Lagrangian Framework • Effective Lagrangian Probing non-standard top-gluon couplings at hadron colliders

  12. Ⅰ Ⅱ Ⅲ Ⅳ Left-handed quark doublet Right-handed quark Higgs doublet Gauge field strength Framework • Effective Operator － Only SM particles －　SU(3)× SU(2) × U(1)Symmetry W.Buchmuller and D.Wyler, NPB268(1986)621 e.g. Probing non-standard top-gluon couplings at hadron colliders

  13. Ⅰ Ⅱ Ⅲ Ⅳ Framework • Top-Gluon Couplings W.Buchmuller and D.Wyler, NPB268(1986)621 J.A.Aguilar-Saavedra, NPB812(2009)181 B.Grzadkowski, Z.Hioki, KO, J.Wudka, NPB689(2004)108 Equation of Motion Probing non-standard top-gluon couplings at hadron colliders

  14. Ⅰ Ⅱ Ⅲ Ⅳ Memo Framework • Feynman Rule • Non-standard top-gluon couplings • ttg coupling • ttgg coupling (CMDM) (CEDM) Probing non-standard top-gluon couplings at hadron colliders

  15. Ⅰ Ⅱ Ⅲ Ⅳ 2 Memo : can contribute : PDF Framework • Cross section 2 + + + + Probing non-standard top-gluon couplings at hadron colliders

  16. Ⅲ Analyses

  17. Ⅰ Ⅱ Ⅲ Ⅳ P. Haberl, et.al. PRD53 (1996) 4875 Analyses • Current bounds from Tevatron － Experimental result CDF: D0 : － Theoretical value (QCDCTEQ6.6M -NNLO approx.) CDF collaborationPublic CDF note 9448 D0 CollaborationarXiv:0903.5525 P.M. Nadolsky et al., PRD 78 (2008) 013004 Probing non-standard top-gluon couplings at hadron colliders

  18. Ⅰ Ⅱ Ⅲ Ⅳ Analyses • Experimental valueVSTheoretical value － Experimental value　 （ including PDF uncertainty） － Theoretical value Probing non-standard top-gluon couplings at hadron colliders

  19. Ⅰ Ⅱ Ⅲ Ⅳ CDF＋D0 CDF D0 Analyses Probing non-standard top-gluon couplings at hadron colliders

  20. Ⅰ Ⅱ Ⅲ Ⅳ Analyses • Allowed region of Probing non-standard top-gluon couplings at hadron colliders

  21. Ⅰ Ⅱ Ⅲ Ⅳ Analyses • LHC Study (1) Can we observe the effects of and from at ? －　 Probing non-standard top-gluon couplings at hadron colliders

  22. Ⅰ Ⅱ Ⅲ Ⅳ Analyses － 　　 Total cross section of top pair production might be large! Probing non-standard top-gluon couplings at hadron colliders

  23. Ⅰ Ⅱ Ⅲ Ⅳ Analyses • LHC study（2） There are no deviation from SM prediction → New bounds ofand e.g. We got SM value Error （Pure assumption） Probing non-standard top-gluon couplings at hadron colliders

  24. Ⅰ Ⅱ Ⅲ Ⅳ Analyses Adding Tevatron result （Tevatron） （LHC） Probing non-standard top-gluon couplings at hadron colliders

  25. Ⅰ Ⅱ Ⅲ Ⅳ and might be strongly constrained Analyses • New (virtual) bounds of （Tevatron + LHC） Tev. LHC Probing non-standard top-gluon couplings at hadron colliders

  26. III. Summary

  27. Ⅰ Ⅱ Ⅲ Ⅳ Summary Non-standard top-gluon couplings are studied － Model-independent approach → Effective Lagrangian 　 →　　（CMDM）and（CEDM) induce non-SM effect. →Estimation of top par production are performed － From Tevatron To LHC 　 →Tevatron result permits 　　→ if , we might observe 　　→ even if, and are strongly constrained Thank you! Probing non-standard top-gluon couplings at hadron colliders

  28. Back up

  29. Analyses • LHC study（３） Can we detect deviation from SM perdition of angler distributions of produced top quark ? Probing non-standard top-gluon couplings at hadron colliders

  30. Angler distribution of produced top quark might be also good signal of and Analyses Probing non-standard top-gluon couplings at hadron colliders

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