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QCD Effects in High-Energy Processes

QCD Effects in High-Energy Processes. C.S. Li and S.H. Zhu Peking University June 2005, Beijing. With contributions from Y. Gao, L.G. Jin, Q. Li, J.J. Liu, L.L. Yang. In collaboration with: S. Godfrey, W. Hollik, C.S. Huang, R. J. Oakes & C.P. Yuan. Outline. Introduction

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QCD Effects in High-Energy Processes

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  1. QCD Effects in High-Energy Processes C.S. Li and S.H. Zhu Peking University June 2005, Beijing With contributions from Y. Gao, L.G. Jin,Q. Li, J.J. Liu,L.L. Yang In collaboration with: S. Godfrey, W. Hollik, C.S. Huang, R. J. Oakes & C.P. Yuan

  2. Outline • Introduction • QCD effects in Higgs physics • QCD effects in SUSY • QCD effects in top physics • Factorization & re-summation • Summary

  3. (1) Introduction • QCD effects at high energy scale (perturbative region) are important in testing QCD & searching new physics beyond the SM. • Evaluating QCD effects are complicated at high energy scale due to: infrared & UV singularities, multiple final states, multiple loops, multiple scales (PT distribution, new particle etc.), • Recent progress on QCD, for examples • QCD effects in particles decay & production of SM (Higgs, Top) and/or new physics (e.g. SUSY) • Resummation techniques

  4. MHV • AP splitting function at 3-loop, • NNLO QCD di-lepton rapidity distribution of Drell-Yan process • NLO background • Etc.

  5. (2) QCD effects in Higgs physics • Is there fundamental scalar field in Nature? • Is electro-weak (EW) symmetry really broken by Higgs vacuum expectation value (VEV)? • 2HDM, 3HDM, Triplet, SUSY Higgs, Little Higgs, Fat Higgs…? • QCD effects are important to answer above questions because they will affect Higgs production and decay. • Higgs physics is certainly the primary goal of next generation colliders.

  6. Decay of SM Higgs

  7. SM Higgs Production at Hadron Colliders • Recent reviews by A. Djouadi, hep-ph/0412238, 0503172 LHC

  8. Search of SM Higgs at Hadron Colliders

  9. QCD corrections to H-> • H.Q.Zheng, D.D.Wu, Phys. Rev. D 42, (1990) 3760 • A.Djouadi, M.Spira, J,J,van der Bij, P.M.W.Zerwas, • Phys.Lett. B257 (1991) 187 • S.Dawson, R.P.Kauffman, Phys.Rev. D47 (1993) 1264 A.Djouadi, M.Spira, P.M.W.Zerwas, Phys.Lett. B311 (1993) 255-260K.Melnikov,O.I.Yakovlev Phys.Lett. B312 (1993) 179-183M.Inoue, R.Najima, T.Oka, J.Saito, Mod.Phys.LettA9(1994)1189 • M.Steinhauser hep-ph/9612395 • J.Fleischer, O.V.Tarasov, V.O.Tarasov, Phys.Lett. B584 (2004) 294-297

  10. Inclusive cross section for gg->H • The history of QCD corrections to this process is long. • 14 years ago • NLO QCD corrections to gg->H are found to be large • A.Djouadi, M.Spira, P.M.Zerwas Phys.Lett.B264 (1991) 440 • S.Dawson Nucl.Phys.B359 (1991) 283 • D.Graudenz, M.Spira, P.M.Zerwas, Phys.Rev.Lett, 70 (1993) 1372 • M.Spira, A.Djouadi, D.Graudenz, P.M.Zerwas, Phys.Lett.B318 (1993) 347 • M.Spira, A.Djouadi, D.Graudenz, P.M.Zerwas, Nucl.Phys.B453 (1995) 17

  11. NNLO QCD corrections to gg->H (effective Lagrangian method) • *Two-loop corrections to H-g-g vertex • R.V.Harlander, Phys.Lett.B492 (2000) 74 • *Soft-plus-virtual gluon corrections • S.Catani, D.de.Florian, M.Grazzini, JHEP 0105 (2001) 025 • R.V.Harlander,W.B.Kilgore,Phys.Rev.D64 (2001) 013015 • *Two-to-three body processes • R.V.Harlander, W.B.Kilgore, Phys.Rev.Lett.88 (2002) 201801 • C.Anastasiou, K.Melnikov, Nucl.Phys.B646 (2002) 220 • V.Ravindran, J.Smith, W.L.Van Neerven, Nucl.Phys.B665 (2003) 325 • V.Ravindran, J.Smith, W.L.van Neerven, Pramana 62 (2004) 683 • *NNLL Catani et al., Laenen et al., vogelsang et al. see the Resummation part in this talk

  12. Taken from V.Ravindran et al., hep-ph/0405263

  13. NLO QCD corrections to gg->H+1jet+X (in effective Lagrangian method ) • D.de.Florian, M.Grazzini, Z.Kunszt, Phys.Rev.Lett.82 (1999)5209 • S.Catani, D.de Florian, M.Grazzini,JHEP 0201 (2002) 015 • V.Ravindran, J.Smith, W.L.Van Neerven, Nucl.Phys.B634 • (2002) 247Christopher J.Glosser, Carl R.Schmidt, JHEP 0212 (2002) 016

  14. NLO QCD correction to gg->diphoton • (background to gg->H->diphoton) Z.Bern, L.J.Dixon, C.Schmidt • Phys.Rev.D66 (2002) 074018 • Associated production of Higgs with top pairs(NLO) • W.Beenakker, S.Dittmaier, M.Kramer, B.Plumper, M.Spira, • P.M.Zerwas • Nucl.Phys.B653 (2003) 151 Phys.Rev.Lett.87 (2001) 201805 • S. Dawson, C. Jackson, L.H. Orr, L. Reina, D. Wackeroth Phys.Rev.D68 (2003) 034022

  15. Tevatron LHC W.Beenakker etal., Phys.Rev.Lett.87 (2001) 201805

  16. The relevant Yukawa coupling can be large in SUSY models • bg->bh at LHC C.S. Huang & S.H. Zhu, PRD60:075012,1999 • F. Maltoni, Z. Sullivan, S. Willenbrock, Phys.Rev. D67 (2003) 093005S.Dawson etc., Phys.Rev.Lett. 94 (2005) 031802 • In collinear limit • d/dt ~1/t • From the figure, the collinear limit is about • After integration • The factorization should be about

  17. Exclusive Higgs Boson Production with bottom quarks pairs at Hadron Colliders(SM and SUSY Higgs boson)(NLO) • S.Dawson, C.Jackson, L.H.orr, L.Reina, D.Wackeroth Phys.Rev. D69 (2004) 074027 • QCD Corrections to Jet Correlations in Weak Boson FusionT.Figy,D.Zeppenfeld, Phys.Lett. B591 (2004) 297 Phys.Rev. D68 (2003) 073005; T.Figy, C.Oleari, D.Zeppenfeld • Phys.Rev. D68 (2003) 073005

  18. SM Higgs Production at ILC Taken from A.Bartl, S.Hesselbach hep-ph/0404178 R.D.Heuer et al., hep-ph/0106315

  19. NLO QCD Corrections to e+e-tth • QCD Corrections to Associated Higgs Boson-Heavy Quark Production, S.Dawson, L.Reina • Phys.Rev. D59 (1999) 054012S. Dittmaier, M. Krämer, Y. Liao, M. Spira, P.M. Zerwas, PLB441 (1998) 383 • NLO QCD corrections to • Chen Hui,Ma Wen-Gan,Zhang Ren-you,Zhou Pei-Jun, Hou Hong-Sheng,Sun Yan-Bin • Nucl.Phys. B683 (2004) 196-218

  20. MSSM Higgs Decay • QCD and SUSY QCD correction to H->tb. • A.Mendez, A.Pomarol, Phys.Lett.B252 (1990) 461 • C.S.Li, R.J.Oakes, Phys. Rev. D 43 (1991) 855 • C.S.Li, J.M.Yang, Phys.Lett.B315(1993) 367 • Heinz Konig, Mod. Phys. Lett. A10 (1995) 1113 • A. Bartl, H. Eberl, K. Hidaka, T. Kon, W. Majerotto, Y. Yamada, Phys.Lett.B378:167-174,1996 • SUSY-QCD decoupling properties in H-> t b M. Herrero, S. Penaranda, D.Temes, Phys.Rev. D64 (2001) 115003

  21. QCD and SUSY QCD correction to t-> H+ b. • C.S.Li, T.C.Yuan, Phys.Rev.D42:3088-3092,1990, Erratum-ibid.D47:2156,1993 • J. Liu,Y.P.Yao, Int.J.Mod.Phys.A6(1991)4925; Phys.Rev.D46:5196-5199,1992 • B.Q.Hu, C.S.Li, J.M.Yang, Chin.Phys.Lett.10:329-332,1993 • A. Czarnecki, S.Davison, Phys.Rev.D47:3063-3064,1993 • QCD and SUSY QCD correction to H+->stop sbottom . A.Bartl, H.Eberl, K.Hidaka, T.Kon, W.Majerotto, Y.YamadaPhys.Lett. B373 (1996) 117

  22. QCD and SUSY-QCD corrections to the Three-Body Decay of the Charged Higgs BosonXiao-Jun Bi, Yuan-Ben Dai, Xiao-Yuan Qi, • Phys.Rev. D61 (2000) 015002 • Improved SUSY QCD corrections to Higgs decay into quark or squark pair • H. Eberl, K. Hidaka, S. Kraml, W. Majerotto, Y. Yamada • Phys.Rev. D62 (2000) 055006 • SUSY-QCD corrections to the MSSM hbb vertex in the decoupling limit • Howard E. Haber, Maria J. Herrero, Heather E. Logan, Siannah Penaranda, Stefano Rigolin, David Temes • Phys.Rev.D63 (2001) 055004

  23. MSSM Higgs Production at Hadron Colliders • (Recent review by Djouadi, hep-ph/0503173 )

  24. NNLO QCD corrections to pp->(pseudo) scalar Higgs boson • R.V.Harlander, W.B.Kilgore, JHEP 0210 (2002) 017 • V.Ravindran,J.Smith,W.L.Van Neerven, Nucl.Phys.B665 (2003) 325 • C.Anastasiou, K.Melnikov, Phys.Rev.D67 (2003) 037501 • B.Field,J.Smith,M.E.Teieda-Yeomans,W.L.Van.Neerven • Phys.Lett. B551 (2003) 137 • Effects of SUSY-QCD in hadronic Higgs production at NNLOR.V.Harlander, M.SteinhauserPhys.Rev. D68 (2003) 111701

  25. NLO QCD corrections to Higgs+1 high PT bottom quark production • Stefan Dittmaier, Michael Krämer, Michael Spira • Phys.Rev. D70 (2004) 074010 • J. Campbell, R.K. Ellis, F. Maltoni, S. Willenbrock • Phys.Rev. D67 (2003) 095002 J. Campbell, S. Dawson, S. Dittmaier, C. Jackson, M. Kramer, F. Maltoni, L. Reina, M. Spira, D. Wackeroth, S. Willenbrock • hep-ph/0405302 • SUSY-QCD corrections to gb->bh • Junjie Cao, Guangping Gao, Robert J. Oakes, Jin Min Yang • Phys.Rev. D68 (2003) 075012

  26. NLO QCD corrections to Higgs+2 high PT bottom quark production • Stefan Dittmaier, Michael Krämer, Michael Spira • Phys.Rev. D70 (2004) 074010 • S. Dawson, C.B. Jackson, L. Reina, D. Wackeroth • Phys.Rev. D69 (2004) 074027

  27. NLO QCD corrections to gb->tH- •  Shou-Hua Zhu Phys.Rev. D67 (2003) 075006,hep-ph/0112109 • T.Plehn Phys.Rev. D67 (2003) 014018, hep-ph/0206121 • E Berger, T Han, J Jiang, T Plehn, hep-ph/0312286 • SUSY QCD corrections to gb->tH- • G. Gao ,G. Lu Z. Xiong, J.M.Yang • Phys.Rev. D66 (2002) 015007 • NLO QCD corrections to bb->WH • Wolfgang Hollik, Shou-hua Zhu • Phys.Rev. D65 (2002) 075015

  28. SH Zhu, Phys.Rev. D67 (2003) 075006,hep-ph/0112109

  29. NLO QCD corrections to neutral Higgs pair production • Li Gang Jin, Chong Sheng Li, Qiang Li, Jian Jun Liu, Robert J. Oakes • Phys.Rev. D71 (2005) 095004 • NLO QCD corrections to • Qiang Li, Chong Sheng Li, Jian Jun Liu, Li Gang Jin, C.-P.Yuan • hep-ph/0501070 • NLO QCD corrections to • Hou Hong-Sheng, Ma Wen-Gan, Zhang Ren-You, Jiang Yi, Han Liang, Xing Li-RongPhys.Rev. D71 (2005) 075014

  30. Qiang Li, Chong Sheng Li, Jian Jun Liu, Li Gang Jin, C.-P.Yuan, hep-ph/0501070

  31. MSSM Higgs Production at ILC Taken from A.Bartl, S.Hesselbach hep-ph/0404178 A.Djouadi,Montpellier, hep-ph/0205248

  32. Taken from S. Dittmaier, M. Krämer, Y. Liao, M. Spira, P.M. Zerwas Phys.Lett. B478 (2000) 247

  33. NLO QCD Corrections to e+etth( and bbH) • S. Dittmaier, M. Krämer, Y. Liao, M. Spira, P.M. ZerwasPhys.Lett. B478 (2000) 24 • Shou-hua Zhu, hep-ph/0212273 • Petra Häfliger, Michael Spira, hep-ph/0501164 • Wu Peng, Ma Wen-Gan, Hou Hong-Sheng, Zhang Ren-You, Han Liang, Jiang Yi, hep-ph/0505086 • NLO QCD corrections to • Bernd A. Kniehl, Fantina Madricardo, Matthias Steinhauser • Phys.Rev. D66 (2002) 054016

  34. (3) QCD effects in SUSY • In a sense, MSSM is Standard Model of new physics beyond SM • Many advantages: solving gauge hierarchy problem, GUT, dark matter… • Is SUSY the real symmetry at TeV scale? Could be answered at future colliders? • QCD effects are important, especially for colored particle decay and production, and could be essential to distinguish SUSY breaking scenarios.

  35. Sample spectra for SUSY particles for SUGRA, GMSB and AMSB scenarios. hep-ph/0106315

  36. The reach of the Tevatron, the LHC, and a 0.5 and 1 TeV LC for SUSY discovery. A. Belyaev,hep-ph/0410385

  37. NLO QCD corrections to SUSY particle decays • squark • gluino

  38. Hadron colliders (including the NLO QCD corrections) • - squarks,gluinos • - top-squark pairs • - gaugino pairs, slepton pairs • - gluino and gaugino

  39. - top-squark and chargino - R-parity violating processes

  40. Some typical results M. Spira, hep-ph/0211145 M. Krämer, hep-ph/9809259

  41. QCD effects can reach 20-30%. L.G. Jin, C.S. Li & J.J. Liu, EPJC30 (2003) 77

  42. Generally, the QCD corrections are large and positive, increasing the total cross sections by 10-90%. The inclusion of the NLO corrections reduces the LO scale dependence by a factor 3-4 and reaches a typical level of ~10-15% which serves as an estimate of the remaining theoretical uncertainty. M. Spira,hep-ph/0211145

  43. Linear collider (including the NLO QCD corrections) • - squark pairs

  44. At linear colliders, in general, the QCD corrections are positive and dominant over other ones at the low colliding energy (e.g. 500-1000 GeV).

  45. (4) QCD effects in top physics • Is top really special just because of its mass at EW scale and the heaviest one among known particles? • Top with huge mass has saved SM, otherwise theoretical prediction are not consistent to precision data at LEP and SLC. • Top also brought troubles to dynamical EW symmetry breaking mechanisms (Technicolor, top-see-saw, Little Higgs, Higgsless models…) • QCD effects are important in testing SM or distinguishing new physics: SM or SUSY, models of dynamical symmetry breaking, and so on.

  46. Top decay • M. Jezabek,J.H. Kuhn, Nucl.Phys.B314(1989)1 • A. Czarnecki, Phys.Lett.B252(1990)467 • C.S.Li, R.J.Oakes, T.C.Yuan, Phys.Rev.D43(1991)3759 • C.F.Qiao, S.H.Zhu, Phys.Lett. B451 (1999) 93 • C.S.Li, J.M. Yang, B.Q. Hu, PRD48(1993)5425 • C.S.Li, R.J.Oakes, J.M.Yang,Phys.Rev.D54(1996)6883 • A. Czarnecki, K.Melnikov, Nucl.Phys.B544(1999)520 • K.G.Chetyrkin,R.Harlander,T.Seidensticker, Steinhauser, Phys.Rev.D60(1999)114015 • A.Ghinculov, Y.P.Yao, Mod.Phys.Lett.A15(2000)925 • M.Slusarczyk, hep-ph/0404249

  47. NLO QCD: -8.4% M. Jezabek,J.H. Kuhn, Nucl.Phys.B314(1989)1 NNLO QCD: -2%, M.Slusarczyk, hep-ph/0404249

  48. Polarized Top Decay: M.Fischer,S.Groote,J.G.Korner,M.C.Mauser,B.Lampe,Phys.Lett.B451(1999)406; M.Fischer,S.Groote,J.G.Korner,M.C.Mauser,Phys.Rev.D64(2001)017301;65(2002)054036; W.Bernreuther, M.Fuecker, Y. Umeda Phys.Lett. B582 (2004) 32 A. Brandenburg, Z.G. Si, P. Uwer, Phys.Lett. B539 (2002) 235. Decay distributions: A. Brandenburg, M. Maniatis, Phys.Lett. B545 (2002) 139

  49. FCNC top rare decay via SUSY QCD C.S.Li, R.J.Oakes and J.M.Yang, PRD49(1994)293;56(1997) 3156(E) J.M.Yang , C.S.Li, Phys.Rev.D49:3412-3416,1994, Erratum-ibid.D51:3974,1995 G.Couture, C.Hamzaoui and H.Konig, PRD52(1995)1713 G.Couture, M.Frank and H.Konig, PRD56(1997)4213 G.M.de Divitiis, R.Petronzio and L.Silvestrini, NPB504(1997)45 J.Guasch and J.Sola, NPB562(1999)3 J.J. Liu, C.S.Li, L.L.Yang, L.G.Jin., PLB 599 (2004) 99

  50. Three mechanisms for Single top Production at NLO QCD at Hadron Colliders • ud->W*->tb, M.C.Smith,S.Willenbrock,Phys.Rev.D54(1996)6696 C. S. Li, R.J. Oakes, J.M.Yang, H.Y. Zhou, PRD57 (1998) 2009 • bu->td, G.Bordes,B.van.Eijk,Nucl.Phys.B435(1995)23;T.Stelzer, Z.SullivanS.Willenbrock,Phys.Rev.D56(1997)5919 • bg->tW-, S.H. Zhu Phys. Lett. B 524 (2002) 283 ;537( 2002) 351(E)

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