2011 QCD and High Energy Interactions - Rencontres de Moriond ...

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NNLO σ/ σSM 95% CL Upper Bound on 10 1 1 10 2 s=7 TeV 1 ∫ L dt=1 fb ATLAS Preliminary (Simulation) H→ WW H→ 4l H→ ZZ→ llbb H→ ZZ→ llνν H→γγ VH, H→ bb H→ττ Combined ± 1σ ± 2σ 10 100 200 300 400 500 600 mH[GeV] Figure 4: Left: the expected limits on several Higgs boson production channels and the combined limit assuming Standard Model branching ratios at ATLAS with 1 fb −1 of integrated luminosity. Right: the expected combined limits on Standard Model Higgs production at CMS, for several values of the integrated luminosity. References 1. F. Englert and R. Brout, Phys. Rev. Lett. 13, 321–323 (1964) 2. P. W. Higgs, Phys. Lett. 12, 132-133 (1964) 3. P. W. Higgs, Phys. Rev. Lett. 13, 508–509 (1964) 4. LEP Working Group for Higgs boson searches, Phys. Lett. B565, 61-75 (2003) 5. CDF and D0 Collaborations and the TEVNPHWG Working Group, arXiv:1103.3233v2 [hep-ex] 6. The ATLAS Collaboration, Expected Performance of the ATLAS Experiment - Detector, Trigger, and Physics, arXiv:0901.0512 [hep-ex] 7. The CMS Collaboration, CMS Technical Design Report, J. Phys. G: Nucl. Part. Phys. 34 (2006) 8. LHC Higgs Cross Section Working Group, S. Dittmaier, C. Mariotti, G. Passarino, and R. Tanaka (Eds.), Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables, CERN- 2011-002, arXiv:1101.0593 [hep-ph] 9. The ATLAS Collaboration, ATLAS Conference note ATLAS-CONF-2011-005 10. The CMS Collaboration, Phys. Lett. B699 (2011) 25-47 11. The ATLAS Collaboration, ATLAS Conference note ATLAS-CONF-2011-026 12. The ATLAS Collaboration, ATLAS Conference note ATLAS-CONF-2011-025 13. M. Carena, S. Heinemeyer, C. E. M. Wagner, and G. Weiglein, Eur. Phys. J. C26 (2003) 601-607 14. The ATLAS Collaboration, ATLAS Conference note ATLAS-CONF-2011-024 15. The CMS Collaboration, arXiv:1104.1619 [hep-ex] 16. The CDF Collaboration, the D0 Collaboration, and the Tevatron New Physics Higgs Working Group, arXiv:1003:3363 [hep-ex] 17. The CMS Collaboration, CMS Physics Analysis Summary CMS-PAS-HIG-11-001 18. The CMS Collaboration, CMS Physics Analysis Summary CMS-PAS-HIG-11-002 19. The ATLAS Collaboration, ATLAS Note ATL-PHYS-PUB-2010-015 20. The ATLAS Collaboration, ATLAS Note ATL-PHYS-PUB-2011-001 21. The CMS Collaboration, CMS Note 2010/008
THEORETICAL UNCERTAINTIES IN HIGGS SEARCHES Abdelhak DJOUADI Laboratoire de Physique Théorique, Université Paris-Sud XI et CNRS, F-91405 Orsay, France. Theory Unit, CERN, 1211 Genève 23, Switzerland. In this talk, we respond to the comments and criticisms made by the representatives of the CDF and D0 collaborations on our recent papers in which we point out that the theoretical uncertainties in the Higgs production cross section have been largely underestimated and, if properly taken into account, will significantly loosen the Tevatron Higgs exclusion bounds. We show that our approach to the theoretical uncertainties is fully justified and, furthermore, provide additional details on our statistical analysis of the CDF and D0 exclusion limit which show that it is conceptually correct. 1 Introduction In two earlier papers 1,2 , we updated the theoretical predictions for the production cross sections of the Standard Model Higgs boson at the Tevatron collider, focusing on the main search channel, the gluon–gluon fusion mechanism gg → H, including the relevant higher order QCD and electroweak corrections 3 . We then estimated the various theoretical uncertainties affecting these predictions: the scale uncertainties which are viewed as a measure of the unknown higher order effects, the uncertainties from the parton distribution functions (PDFs) and the related errors on the strong coupling constant αs, as well as the uncertainties due to the use of an effective field theory (EFT) approach in the determination of the radiative corrections in the process at nextto-next-to-leading order (NNLO). We found that contrary to the Higgs–strahlung processes 3 , where the rates are well under control as the uncertainty is less than ≈ 10%, the theoretical uncertainties are rather large in the case of the gluon–gluon fusion channel, possibly shifting the central values of the NNLO cross sections by up to ≈ 40%. These uncertainties are thus significantly larger than the ≈ 10%–20% error assumed by the CDF and D0 experiments in their analysis that has excluded the Higgs mass range MH =158–175 GeV at 95% CL 4,5 . As gg → H is by far the dominant Higgs production channel in this mass range, we concluded that the above exclusion limit should be reconsidered in the light of these large theoretical uncertainties. After our papers appeared, some criticisms have been made by the members of the CDF and D0 collaborations and of the Tevatron New Physics and Higgs working group (TevNPHWG) 6 concerning the theoretical modeling of the gg → H production cross section that we proposed. This criticism was made more explicit at this conference 7 . In this note, we respond to this criticism point by point and show that that our approach to the theoretical uncertainties is fully justified. In particular, we will make use of of a recent collective effort 8 made by theorists along with experimentalists of the ATLAS and CMS collaborations to evaluate the Higgs cross section at the LHC, with a special attention to the gluon fusion mechanism which is also the process of interest here. Several issues discussed in our papers 1,2 have been indeed addressed in
Page 1 and 2: 2011 QCD and High Energy Interactio
Page 3 and 4: Proceedings of the XLVIth RENCONTRE
Page 5 and 6: 2011 RENCONTRES DE MORIOND The XLVI
Page 7 and 8: Foreword Contents 1. Higgs Searches
Page 9: 1. Higgs
Page 12 and 13: 95% CL Limit/SM 10 1 Tevatron Run I
Page 14 and 15: Events/5 GeV 6 10 5 10 4 10 3 10 2
Page 16 and 17: Events / 0.5 CDF Run II Preliminary
Page 18 and 19: For the most sensitive sub-channel
Page 20 and 21: Table 1: Table listing the various
Page 22 and 23: various SM Higgs mass hypotheses. T
Page 24 and 25: constraints on parameters are given
Page 26 and 27: Figure 2: Invariant mass of the ele
Page 28 and 29: Figure 4: CDF Exclusion limits for
Page 30 and 31: Table 1: Main phases of 2010 commis
Page 32 and 33: Table 4: Parameter list for early (
Page 34 and 35: luminosity of 1.2×10 33 cm −2 s
Page 36 and 37: 2 QCD Analysis settings HERA PDFs a
Page 38 and 39: min 2 - 2 20 15 10 5 0 H1 and ZEUS
Page 40 and 41: SM σ / σ 95% CL Limit on 3 10 2 1
Page 44 and 45: the report of this working group. I
Page 46 and 47: 2.3 The impact of different PDF par
Page 49 and 50: SUSY Searches at the Tevatron Ph. G
Page 51 and 52: on the quality (loose or tight) and
Page 53 and 54: SUSY searches at ATLAS N. Barlow, o
Page 55 and 56: channel. These results are combined
Page 57 and 58: Figure 2: The top left plot shows t
Page 59: 2010 data. Analysis techniques for
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Page 64 and 65: sign leptons is particularly intere
Page 66 and 67: N of events 5 10 DATA 10 4 3 10 10
Page 68 and 69: ) [pb] ν e → B(W’ × σ 10 1 -
Page 70 and 71: 2 Searches in the dijet final state
Page 72 and 73: ing that the neutrinos were the onl
Page 75 and 76: The Quasi-Classical Model in SU(N)
Page 77 and 78: g (γ µ kµ) γ µ Aa µ g (pk)
Page 79: 3. Top
Page 82 and 83: of their vertex with respect to the
Page 84 and 85: of about 9%. 3.1 Differential Cross
Page 86 and 87: Figure 5: Summary of most recent CD
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hood technique, with a simultaneous
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momentum direction of the b quark f
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Events 200 150 100 50 -1 DØ L=5.4
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after all corrections in the M t¯t
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for prompt J/ψ under the fully tra
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2 Events / 20 MeV/c 50 40 30 20 10
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ATLAS - consists of four parts (mon
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5 D mesons High cross-sections of D
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μ +X') [nb/GeV] → b+X → (pp T
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GeV) μ |
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HEAVY FLAVOUR IN A NUTSHELL Robert
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Figure 1: Overlapping constraints o
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Figure 3: Constraints on new physic
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RECENT B PHYSICS RESULTS FROM THE T
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(IP) distributions are fitted separ
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decays CDF extracts Using a 5.94 fb
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Search for B 0 s → µ+ µ − and
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Ref. 10,11 . The expected GL distri
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IN PURSUIT OF NEW PHYSICS WITH B DE
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τK + K −/τBs 1.01 1.00 0.99 0.9
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CHARMLESS HADRONIC B-DECAYS AT BABA
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surements (fL ∼ 0.5). Several att
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Estimating the Higher Order Hadroni
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the resulting exponent suggests to
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The counterpart of the ground-state
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(a) Tree level signal decay b ¯Bs
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the B0 d system LHCb profits from i
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This result is based on averaging o
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y non-perturbative effects. Using t
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e M(Dπ) distributions obtained D +
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CHARM PHYSICS RESULTS AND PROSPECTS
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LHCb is working towards its first m
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Two body hadronic D decays Yu Fushe
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where the effective coefficients aA
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6. J. J. Sakurai, Phys. Rev. 156, 1
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states: 6π, 2K4π, 4K2π, KSK3π 1
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egion of X(3872), which corresponds
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Figure 1: The π 0 recoil mass spec
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η → π + π − π 0 η ′ →
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conservation. This second principle
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many of them come from gluon nonper
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Latest Jets Results from the Tevatr
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in for the inclusive trijet event s
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RECENT RESULTS ON JETS FROM CMS F.
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dy (pb/GeV) /dp 2 d 10 10 10 9 10
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RECENT RESULTS ON JETS WITH ATLAS G
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| y| < 0.3 ATLAS Preliminary 2.1 <
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EPOS 2 and LHC Results TanguyPierog
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positions are randomly distributed
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ABOUT THE HELIX STRUCTURE OF THE LU
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Figure 2: Left: Correlations betwee
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Improving NLO-parton shower matched
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due to the inclusion of higher orde
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New Results in Soft Gluon Physics C
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Figure 2: Spacetime depiction of Dr
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Central Exclusive Meson Pair Produc
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in the CEP cross section. However i
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AN AVERAGE b-QUARK FRAGMENTATION FU
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1/N dN/dx 3.5 3 2.5 2 1.5 1 0.5 ALE
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W + W + jj at NLO in QCD: an exotic
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Σ fb Σ fb 3.5 3.0 2.5 2.0 0.65 0.
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W/Z+Jets and W/Z+HF Production at t
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Figure 2: Measured inclusive jet di
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W and Z physics with the ATLAS dete
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SHERPA 9 MC generators but not by P
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W/Z + Jets results from CMS V. CIUL
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Events / 0.1 600 500 400 300 200 10
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TEVATRON RESULTS ON MULTI-PARTON IN
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iterative midpoint cone algorithm w
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INVESTIGATIONS OF DOUBLE PARTON SCA
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¦ § ¦ ¨ ¥ ¦ ¨ § ¦ © ¦ §
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Figure 4: Two-dimensional distribut
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SOFT QCD RESULTS FROM ATLAS AND CMS
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as a function of multiplicity for t
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Determination of αS using hadronic
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α S (m Z 0) 0.15 0.14 0.13 0.12 0.
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Reaching beyond NLO in processes wi
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dσ/dp t,max [fb/GeV] 10 5 10 4 10
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Nonlocal Condensate Model for QCD S
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The lower bound for the integration
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AN ALTERNATIVE SUBTRACTION SCHEME F
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where MBorn,g is the underlying Bor
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THE NNPDF2.1 PARTON SET F. CERUTTI
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ottom masses mb of 4.25, 4.5, 5.0 a
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HOLOGRAPHIC DESCRIPTION OF HADRONS
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∫ SYM = κ d 4 ( 1 xdzTr 2 h(z)F
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Nuclear matter and chiral phase tra
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fact that for Nc ≫ 3 a gas of fre
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Recent Results on Light Hadron Spec
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Figure 3: Mass spectrum fitting wit
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MEASUREMENT OF THE J/ψ INCLUSIVE P
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2 Counts per 40 MeV/c 120 100 80 60
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STUDY OF Ke4 DECAYS IN THE NA48/2 E
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photons were accepted while particl
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6. Structure Functions Diffraction
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2 Hadronic Final States and Diffrac
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3 Summary A brief overview of recen
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Using HERA Data to Determine the In
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k f n 0.4 0.2 0 -0.2 0.4 0.2 0 -0.2
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The singular term, on the other han
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Pomeron Kernel: The leading order B
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DIFFRACTION, SATURATION AND pp CROS
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In Ref. 6 , the saturated Froissart
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Transverse Energy Flow with Forward
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1/N d dE t /dη 0.1 0.09 0.08 0.07
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7. Heavy Ions
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dη)/(0.5〈 N 〉 ) part ch (dN 10
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) 3 (fm long R side R out R 400 350
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correlation density is computed as
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Away-side gaussian width 1.4 1.2 1
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Figure 1: (a) J/ψ rapidity distrib
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lower x, or forward rapidity one ex
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φ ∆ /d assoc dN trig 1/N 0.5 0.4
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AA,Pythia I 2.5 2.0 1.5 1.0 0.5 0.0
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(1/N ) dN/dA evt J φ Δ ) dN/d (1/
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[GeV] Tower ET Σ 50 45 40 35 30 25
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3 Results 3.1 Dijet Properties in p
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(GeV/c) (GeV/c) T T p < 40 20
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wheredσm(N +N → h+X)/dp Tdy isth
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R AA 0.6 0.5 0.4 0.3 0.2 0.1 0 0.5
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Here D is the diffusion coefficient
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The effect of triangular flow in je
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When both trigger and associated pa
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The first Z boson measurement in th
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Figure 1: Dimuon invariant mass spe
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2. V. Kartvelishvili, R. Kvatadze a
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esolution [ µ m] ! r 0 d 300 250 2
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Figure 5: Differential transverse m
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Figure 1: Average nuclear modificat
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Another way of using direct photons
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Pb R g 2 Nuclear Modifications for
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q T 1/R AA 1.6 1.4 1.2 1 0.8 LO Fra
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] 2 > [g/cm max
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Methods (a) and (c) constrain the e
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EXPERIMENTAL SUMMARY: ENTERING THE
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ut also for valence quarks involved
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The sensitivity to Standard Model H
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Figure 10: Top pair mass spectrum m
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Figure 13: Particle densities (left
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4 Low energy precision Spectroscopy
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asymmetries associated to Bd and Bs
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XLVIth Rencontres de Moriond QCD an
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