qcd effects in high-energy processes
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
QCD Effects in High-Energy Processes
C.S. Li and S.H. ZhuPeking UniversityJune 2005, Beijing
In collaboration with: S. Godfrey, W. Hollik, C.S. Huang, R. J. Oakes & C.P. Yuan
With contributions from Y. Gao, L.G. Jin, Q. Li, J.J. Liu, L.L. Yang
1. Introduction
2. QCD effects in Higgs physics
3. QCD effects in SUSY
4. QCD effects in top physics
5. Factorization & re-summation
6. Summary
Outline
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
(1) Introduction
•MHV
•AP splitting function at 3-loop,
•NNLO QCD di-lepton rapidity distribution of
Drell-Yan process
•NLO background
•Etc.
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.
(2) QCD effects in Higgs physics
Decay of SM Higgs
SM Higgs Production at Hadron Colliders
•Recent reviews by A. Djouadi, hep-ph/0412238, 0503172
LHC
Search of SM Higgs at Hadron Colliders
QCD corrections to H->
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A.Djouadi, M.Spira, J,J,van der Bij, P.M.W.Zerwas,
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M.Steinhauser hep-ph/9612395
J.Fleischer, O.V.Tarasov, V.O.Tarasov, Phys.Lett. B584 (2004) 294-297
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
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NNLO QCD corrections to gg->H (effective Lagrangian method)
*Two-loop corrections to H-g-g vertexR.V.Harlander, Phys.Lett.B492 (2000) 74*Soft-plus-virtual gluon correctionsS.Catani, D.de.Florian, M.Grazzini, JHEP 0105 (2001) 025R.V.Harlander,W.B.Kilgore,Phys.Rev.D64 (2001) 013015 *Two-to-three body processes
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*NNLL Catani et al., Laenen et al., vogelsang et al. see the Resummation part in this talk
Taken from V.Ravindran et al., hep-ph/0405263
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
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(2002) 247Christopher J.Glosser, Carl R.Schmidt, JHEP 0212 (2002) 016
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
Tevatron LHC
W.Beenakker etal., Phys.Rev.Lett.87 (2001) 201805
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) 093005 S.Dawson etc., Phys.Rev.Lett. 94 (2005) 031802
bb h
In collinear limit
d/dt ~1/t
From the figure, the collinear limit is about
After integration
The factorization should be about
ln( / 4 )h bm m
/ 4hm
/ 4ht m
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
SM Higgs Production at ILC
Taken from
A.Bartl, S.Hesselbach hep-ph/0404178
R.D.Heuer et al., hep-ph/0106315
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
tth
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
MSSM Higgs Decay
SUSY-QCD decoupling properties in H-> t b M. Herrero, S. Penaranda, D.Temes, Phys.Rev. D64 (2001) 115003
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
Improved SUSY QCD corrections to Higgs decay into quark or squark pairH. Eberl, K. Hidaka, S. Kraml, W. Majerotto, Y. YamadaPhys.Rev. D62 (2000) 055006
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
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
MSSM Higgs Production at Hadron Colliders
(Recent review by Djouadi, hep-ph/0503173 )
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
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/0405302SUSY-QCD corrections to gb->bh
Junjie Cao, Guangping Gao, Robert J. Oakes, Jin Min Yang
Phys.Rev. D68 (2003) 075012
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
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
NLO QCD corrections to bb->WH
Wolfgang Hollik, Shou-hua Zhu
Phys.Rev. D65 (2002) 075015
SUSY QCD corrections to gb->tH-
G. Gao ,G. Lu Z. Xiong, J.M.Yang
Phys.Rev. D66 (2002) 015007
SH Zhu, Phys.Rev. D67 (2003) 075006,hep-ph/0112109
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
Hou Hong-Sheng, Ma Wen-Gan, Zhang Ren-You, Jiang Yi, Han Liang, Xing Li-RongPhys.Rev. D71 (2005) 075014
0bb A Z NLO QCD corrections to
Qiang Li, Chong Sheng Li, Jian Jun Liu, Li Gang Jin, C.-P.Yuan
hep-ph/0501070
bb H H
Qiang Li, Chong Sheng Li, Jian Jun Liu, Li Gang Jin, C.-P.Yuan, hep-ph/0501070
MSSM Higgs Production at ILC
Taken from
A.Bartl, S.Hesselbach hep-ph/0404178
A.Djouadi,Montpellier, hep-ph/0205248
Taken from S. Dittmaier, M. Krämer, Y. Liao, M. Spira, P.M. Zerwas Phys.Lett. B478 (2000) 247
NLO QCD Corrections to e+etth( 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
e e H tb
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.
(3) QCD effects in SUSY
Sample spectra for SUSY particles for SUGRA, GMSB and AMSB scenarios.
hep-ph/0106315
The reach of the Tevatron, the LHC, and a 0.5 and 1 TeV LC for SUSY discovery.
A. Belyaev, hep-ph/0410385
• squark
• gluino
NLO QCD corrections to SUSY particle decays
243 (1998) PLB419 Bartl A.
510 '~,~
6975 (1997) PRD55 Djouadi A. 175; (1996) PLB386 Kraml S.
1020 ~',~
115007 (1999) PRD59 Bartl A. 5860; (1998) PRD57 Arhrib A.
2040 '~,//~
349 (1997) ZPC75159; (1996) PLB378 Beenakker W.
5030 ~~
0
0
000
et al.
%%~--WqZq
et al.et al.
et al.et al.
%%~-HqAHhq
et al.
%%~gqq
349 (1997) ZPC75159; (1996) PLB378 Beenakker W.
1010 ~/~~
et al.
%%~-qqqqg
Hadron colliders (including the NLO QCD corrections)
- squarks,gluinos
- top-squark pairs
- gaugino pairs, slepton pairs
- gluino and gaugino
51 (1997) 492 NPB163; (1995) 69 ZPC2905; (1995) 74 PRL r W.Beenakke
~~,~~,~~,~~/
et al.
gqggqqqqpppp
3 (1998) 515 NPB r W.Beenakke
~~/
et al.
ttpppp
3780 (1999) 83 PRL r W.Beenakke5871; (1998) 57 PRD Baer H.
~~/~~
/
et al.et al.
llpppp
(E) 099901 (2003) 67 PRD
095014; (2000) 62 PRD 165; (1999) 459 PLB Berger E.L.
~~/
et al.
gpppp
- top-squark and chargino
- R-parity violating processes
L.G. Jin, C.S. Li & J.J. Liu, PLB 561 (2003) 135, EPJC30 (2003) 77
pp t
1 1
1
/ through
T. Plehn, PLB 488 (2000) 359
/
A. Alves PLB 558 (2003) 165
/ through /
L.L. Yang. C.S. Li & J.J. Liu, to be submitted to PRD
pp pp t t b bl
pp pp tl
et al.
pp pp l l v vl l l
Some typical results
M. Spira, hep-ph/0211145
M. Krämer, hep-ph/9809259
L.G. Jin, C.S. Li & J.J. Liu, EPJC30 (2003) 77
~~tpp
QCD effects can reach 20-30%.
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
Linear collider (including the NLO QCD corrections) - squark pairs
073 (2004) 0404 JHEP Arhrib A.242; (2004) 591 PLB Kovarik K.
:scorrection loop-one complete
481 (1996) 472 NPB Eberl H. 1404; (1995) 52 PRD Arhrib A.
~~
et al.et al.
et al.et al.
qqee
055009 (2005) 71 PRD RongLi Xing
:scorrection loop-one complete
15 (1998) 515 NPB Chang C.H.
~~
et al.
et al.
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).
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.
(4) QCD effects in top physics
• 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
Top decay
NLO QCD: -8.4%
M. Jezabek,J.H. Kuhn, Nucl.Phys.B314(1989)1
NNLO QCD: -2%,
M.Slusarczyk, hep-ph/0404249
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
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
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)
Fully differential cross section, B. W. Harris, E. Laenen, L. Phaf, Z. Sullivan, S. Weinzierl, Phys.Rev. D66 (2002) 054024
Including the top quark decay Q.H. Cao, R.Schwienhorst, C.-P. Yuan Phys.Rev.
D71 (2005) 054023 Q.H. Cao, C.-P. Yuan Phys.Rev. D71 (2005) 054022 Q.H. Cao, R.Schwienhorst, J.A. Benitez, R.Brock , C.-P. Yuan hep-ph/0504230
J.Campbell, R. K. Ellis, F.Tramontano Phys.Rev. D70 (2004) 094012
Single Top FCNC productions ILC: C.S. Li, X.M. Zhang, S.H. Zhu, Phys. Rev D60 (1999)
077702 HERA: Belyaev, N.Kidonakis, Phys.Rev. D65 (2002) 037501 Hadron colliders: NLO QCD: N.Kidonakis, A.Belyaev, JHEP 0312 (2003) 004 SUSY-QCD: J.J.Liu, C.S.Li, L.L.Yang, L.G.Jin, NPB705(2005)3; MPLA19, 4
(2004) 317 NLO QCD ( Model-independent FCNC Couplings): J.J.Liu, C.S.Li, L.L.Yang, L.G.Jin, to be submitted to PRD
Single Top Production at e Collider
J.H.Kühn, C.Sturm, P.Uwer, Eur.Phys.J. C30 (2003) 169-182
In SM including QCD corrections (NLO, NNLO, resummation) at Tevatron and LHC
Total cross sections: P.Nason, S.Dawson and R.K.Ellis, Nucl.Phys. B303, (1988) 607 W.Beenakker, H.Kuijf, W.L.van Neerven and J.Smith, Phys.Rev. D40, (1989) 54 ;
pT and y spectra: P.Nason, S.Dawson and R.K.Ellis, Nucl.Phys. B327 (1989) 49W.Beenakker, W.L.van Neerven, R.Meng, G.A.Schuler and J.Smith, Nucl.Phys. B351 (1991) 507 ;
Double-differential spectra: M.L.Mangano, P.Nason and G.Ridolfi, Nucl.Phys. B373 (1992) 295 S.Frixione, M.L.Mangano, P.Nason and G.Ridolfi, Phys. Lett. B351 (1995)555
Resummation(LL): S.Catani, M.L.Mangano, P.Nason and L.Trentadue, Phys. Lett. B378 (1996)329;Nucl. Phys. B478 (1996)273 E.L.Berger and H.Contopanagos, Phys. Rev. D57 (1998)253
Resummation(NLL): N.Kidonakis and G.Sterman, Nucl. Phys. B505 (1997) 321 R.Bonciani, S.Catani, M.L.Mangano and P.Nason, Nucl. Phys. B529 424(1998)
Top Pair production
Recent development(include the soft-gluon corrections at NNLO):
N. Kidonakis, Int. J. Mod. Phys. A15 (2000)1245; Mod. Phys. Lett. A19(2004)405; hep-ph/0410116.N. Kidonakis, Phys. Rev. D64 (2001)014009; Int. J. Mod. Phys. A16 Suppl. 1A, 363 (2001);
N. Kidonakis, E. Laenen, S. Moch, and R. Vogt, Phys. Rev. D64 (2001)114001; Phys. Rev. D67 (2003)074037; Nucl. Phys. A715 (2003)549
N. Kidonakis and R. Vogt, Phys. Rev. D68 (2003) 114014; Eur. Phys. J. C33 (2004) s466.
Top Pair production
N. Kidonakis and R. Vogt Phys. Rev. D68 (2003) 114014
SUSY QCD at PHOTON-PHOTON COLLISION, H.Wang, C.S. Li, H.Y. Zhou, Y.P. Kuang Phys.Rev.D54:4374-4379,1996
SUSY QCD at Tevatron, C.S.Li, H.B. Hu, J.M Yang, C.G. Hu, Phys.Rev.D52:5014-
5017,1995, Erratum-ibid.D53:4112,1996 C.S. Li, H.Y. Zhou, Y. L. Zhu, J. M. Yang, PL B379
(1996) 135 SUSY QCD at LHC, H.Y.Zhou,C.S.Li, Phys.Rev.D55:4421-4429,1997 C.S. Li, C.P. Yuan, H.Y. Zhou PLB424 (1998) 76
(parity violation) NLO QCD effects in VV->tt at ILC, S. Godfrey & S.H. Zhu, hep-ph/0412261.
Top Pair productions
Spin Correlations in top pair production
e+e- colliders: H. X. Liu, C.S. Li, Z. J. Xiao Phys.Lett. B458 (1999) 393
A.Brandenburg, M. Maniatis Phys.Lett. B558 (2003) 79
Hadron colliders: W. Bernreuther, A. Brandenburg, Z.G. Si, P. Uwer Phys.Lett. B509 (2001) 53; Phys.Rev.Lett. 87 (2001) 242002; Int.J.Mod.Phys. A18 (2003) 1357
Polarized photon colliders: A. Brandenburg, Z.G. Si Phys.Lett. B615 (2005) 68
NLO QCD corrections to gg -> t tbar g, A.Brandenburg, S.Dittmaier, P.Uwer, S.Weinzierl, hep-ph/0408137
The interference between production and decay at Linear Colliders:
C. Macesanu Phys.Rev. D65 (2002) 07403 C.Macesanu, L.H. Orr Int.J.Mod.Phys. A16S1A (2001) 369; Phys.Rev.
D65 (2002) 014004
…
Other progress
(5) Factorization and re-summation
Factorization: separate perturbative and nonperturbative contributions to a process.
Re-summation: control the behavior of large logarithms.
Two techniques for factorization & re-summation :
(1) pQCD approach: analysis of Feynman diagrams (CSS)
(2) SCET (soft collinear effective theory) approach: effective Lagrangian and process-dependent operators (For details of SCET, see C. Bauer plenary talk)
The resummation formalism has been developed about two decades ago
• Y. Dokshitzer, D. Diakonov, S. I. Troian (DDT) (Phys.Lett.B79:269,1978; Phys.Rep.58:269,1980)
In order to implement momentum conservation, The resummation is performed in impact parameter b-space.
• G. Parisi, R. Petronzio (Nucl.Phys.B154:427,1979)• G. Curci, M. Greco, Y. Srivastava (Nucl.Phys.B159:451,1979)• J. Collins, D. E. Soper, G. Sterman (CSS) (Nucl.Phys.B250:199,1985)
Resummation in space is also possible
• G. Altarelli, R. K. Ellis, M. Greco, G. Martinelli (Nucl.Phys.B246:12,1984)
• R. K. Ellis, D. A. Ross, S. Veseli (Nucl.Phys.B503:309,1997)• R. K. Ellis, S. Veseli (Nucl.Phys.B511:649,1998)• Kulesza, Stirling (Nucl.Phys.B555:279,1999)
Tq
Tq
pQCD approach of resummation
Non-perturbative prescription
ansatz • J. Collins, D. E. Soper, G. Sterman (1985)• C. Davies, B. Webber, W. Stirling (Nucl.Phys.B256:413,1985)• G. A. Ladinsky, C. P. Yuan (Phys.Rev.D50:4239,1994)• F. Landry, R. Brock, P. M. Nadolsky, C. P. Yuan
(Phys.Rev.D67:073016,2003)
extrapolation • J. W. Qiu, X. F. Zhang (Phys.Rev.D63:114011,2001)
dispersive method• A. Guffanti, G. E. Smye (JHEP 0010:025,2000)
dependent factorization • X. D. Ji, J. P, Ma, F. Yuan (Phys.Rev.D71:034005,2005;
Phys.Lett.B597:299,2004)
*b
Tk
resummation in Higgs production
•I. Hinchliffe, S. F. Novaes (Phys.Rev.D38:3475,1988)
•R. P. Kauffman (Phys.Rev.D44:1415,1991; 45:1512,1992)
•C. P. Yuan (Phys.Lett.B283:395,1992)
•C. Balazs, C. P. Yuan (Phys.Lett.B478:192,2000)
•E. L. Berger, J. W. Qiu (Phys.Rev.Lett.91:222003,2003; Phys.Rev.D67:034026,2003)
•A. Kulesza, W. J. Stirling (JHEP 0312:056,2003)
•G. Bozzi, S. Catani, D. de Florian, M. Grazzini (Phys.Lett.B564:65,2003)
•B. Field (Phys.Rev.D70:054008,2004)
Current accuracy: next-to-next-leading logarithm (NNLL)
Tq
resummation in other processes
Gauge boson pair production•C. Balazs, C. P. Yuan (Phys.Rev.D57:6934-6947,1998)•C. Balazs, Ph.D thesis (hep-ph/9906422)
production•E. L. Berger, J. W. Qiu, Y. L. Wang (Phys.Rev.D71:034007,2005)
Single stop production•T. Plehn (Phys.Lett.B488:359-366,2000)
Polarized W and Z production at RHIC•A. Weber (Nucl.Phys.B403:545-571,1993)•P. Nadolsky, C. P. Yuan (Nucl.Phys.B666:31-55,2003)
Single slepton productionLL Yang, CS Li, JJ Liu, to be submitted to PRD
Tq
Recent developments
resummation with small-x effects•S. Berge, P. Nadolsky, F. Olness, C. P. Yuan (hep-ph/0410375,2004)
Global fit of the non-perturbative parameters•F. Landry, R. Brock, P. M. Nadolsky, C. P. Yuan (Phys.Rev.D67:073016,2003)•strong evidence for universality of the NP function
Universality of the resummed form factor•S. Catani, D. de Florian, M. Grazzini (Nucl.Phys.B596:299,2001)
Calculation of coefficient A3 (extracted from the three loop splitting functions)
•S. Moch, J. A. M. Vermaseren, A. Vogt (Nucl.Phys.B688:101,2004)•A. Vogt, S. Moch, J. A. M. Vermaseren (Nucl.Phys.B691:129,2004)
Tq
Threshold re-summation
Drell-Yan•G. Sterman (Nucl.Phys.B281:310,1987)•S. Catani, L. Trentadue (Nucl.Phys.B327:323,1989;353:183,1991)•A. Vogt (Phys.Lett.B497:228-234,2001)
Higgs•M. Kramer, E. Laenen, M. Spira (Nucl.Phys.B511:523,1998)•S. Catani, D. de Florian, M. Grazzini, P. Nason (JHEP 0307:028,2003)
Heavy quarks•S. Catani, M. L. Mangano, P. Nason, L. Trentadue
(Phys.Lett.B378:329,1996; Nucl.Phys.B478:273,1996)•R. Bonciani, S. Catani, M. L. Mangano, P. Nason (Nucl.Phys.B529:424,1998)
Current accuracy: NNLL for DY and Higgs, NLL for HQ
Joint re-summation
Drell-Yan•E. Laenen, G. Sterman, W. Vogelsang (Phys.Rev.D63:114018,2001)•A. Kulesza, G. Sterman, W. Vogelsang (Phys.Rev.D66:014011,2002)
Higgs•A. Kulesza, G. Sterman, W. Vogelsang (Phys.Rev.D69:014012,2004)
heavy quarks•A. Banfi, E. Laenen (Phys.Rev.D71:034003,2005)
SCET A natural frame for the proof of factorization
and the implement of re-summation • C. W. Bauer, S. Fleming, and M. Luke, Phys.Rev. D63 (2001) 014006• C.W.Bauer, S.Fleming, D.Pirjol, and I.W.Stewart, Phys.Rev. D63, 114020
(2001)• C.W.Bauer, D.Pirjol, and I.W.Stewart, Phys.Rev.Lett. 87, 201806 (2001)• C.W. Bauer, D.Pirjol, and I.W. Stewart, Phys.Rev.D 65, 054022 (2002) • M. Beneke, A.P. Chapovsky, M. Diehl, and Th. Feldmann, Nucl.Phys.B
643, 431 (2002)
Factorization and re-summation in B physics:• J. Chay, and C.Kim, Phys.Rev. D68 (2003) 071502; Phys.Rev. D68 (2003)
034013• S.W.Bosch, R.J.Hill, B.O.Lange, and M.Neubert, Phys.Rev.D 67, 094014
(2003)• C.W. Bauer, and A.V. Manohar, Phys.Rev.D 70, 034024 (2004) • M.Beneke, and Th.Feldmann, Nucl.Phys.B 685, 249 (2004)
Factorization and resummation in High energy hard process:
• Hard Scattering Factorization– C.W.Bauer, S.Fleming, D.Pirjol, I.Z.Rothstein, and I.W.Stewart,
Phys.Rev.D 66, 014017 (2002)
• Enhanced Nonperturbative Effects in Z Decays to jets– C.W.Bauer, A.V.Manohar and M.B.Wise, Phys.Rev.Lett.91, 122001
(2003)– C.W.Bauer, C.Lee, A.V.Manohar and M.B.Wise, Phys.Rev.D 70,
034014 (2004)
• Threshold re-summation– DIS process: A.V.Manohar, Phys.Rev.D 68, 114019 (2003)– Drell-Yan process: A.Idilbi and X.D.Ji, hep-ph/0501006
• QT and joint re-summation– Y.Gao, C.S.Li, and J.J.Liu, hep-ph/0501229
Outline of SCET
Steps = matching + running QCD to SCETI: integrate out modes of
, left with collinear and usoft modes
Decouple transformations in SCETI
SCETI to SCETII : integrate out collinear modes of
)( 2 Q
222 Qp
422 Qp
Application to QT re-summation in Higgs production
A re-derivation of NNLL DDT formula (Y.Gao, C.S.Li, and J.J.Liu, hep-ph/0501229)
)Q,](xC)[fQ,](xC[f)Q,x,(xW
)](Blog)(A[Q),(QS
)Q,x,(xWe1
T2gbb/pT1gaa/pT21gg
2
2
2
2
Tg
,T21gg
Q),(QS
222)0(
21
2
2
Tg
ss
Q
Q
baTT
resum
Qd
dQ
d
dydQdQ
d
T
Numerical evaluation and non-perturbative prescription are simpler in QT space (R. K. Ellis, S.
Veseli, Nucl.Phys.B511:649,1998)
Provided that initial and final states in any process are confined to be soft or collinear, SCET can be applied
The multiple scales problems and nonperturbative effects can be taken into account systematically
(6) Summary(6) Summary
1. QCD effects are significant in almost every case.2. QCD effects (in Higgs physics, in SUSY, in top
physics etc.) are essential in testing SM and searching new physics beyond the SM.
3. Evaluating of QCD effects is complicated at NNLO. So far we don’t know how to calculate NNLO in general case.
4. Re-summation techniques are important in determining observables of high energy hard processes. Current accuracy is up to NNLL.
5. SCET simplifies the proof of factorization and re-summation at leading order of λ(C. Bauer etal.), and the case of next order is worthy of investigating in the future.
6. Need more work!
Thanks for your attention!