QCD Results from the Tevatron
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Transcript of QCD Results from the Tevatron
QCD Results from the Tevatron
QCD Results from the TevatronKenichi HatakeyamaBaylor UniversityAspen Particle Physics ConferenceAspen Center of Physics January 17 - 23, 2010
January 18, 20102OutlineFermilab Tevatron, CDF and D0 DetectorsInclusive jets and dijetsPhotons W/Z+jetsSoft QCD and Exclusive ProductionSummary & Remarks
Only a small fraction of extensive QCD results from the Tevatron can be covered in 20 minutes. More results can be found on:http://www-cdf.fnal.gov/physics/new/qcd/QCD.htmlhttp://www-d0.fnal.gov/Run2Physics/WWW/results/qcd.htm
January 18, 20103Fermilab Tevatron>7 fb-1 delivered(Run I: 120 pb-1)Batavia, ILTevatronMain Injector
Worlds highest energy proton-antiproton collider
Most likely to run until FY2011January 18, 20104CDF and D
CDF & D running well and recording physics quality data with high efficiency (85-90 %)Both experiments have already collected > 6 fb-1 on tape Inclusive Jets & Dijetss, PDFs, Physics beyond the Standard ModelJanuary 18, 20106Jet Production at the TevatronTest pQCD at highest Q2.Unique sensitivity to new physicsCompositeness, new massive particles, extra dimensions, Constrain PDFs (especially gluons at high-x)Measure s
Hard ScatterPDFs
jetjet
underlyingevent
January 18, 20107Inclusive Jet Cross SectionMeasurements span over 8 order of magnitude in d2/dpTdyHighest pTjet > 600 GeV/c
pT (GeV/c)Phys. Rev. D 78, 052006 (2008) pT (GeV/c)Phys. Rev. Lett. 101, 062001 (2008)January 18, 20108Inclusive Jet Cross SectionBoth CDF and D0 measurements are in agreement with NLO predictionsBoth in favor of somewhat softer gluons at high-xExperimental uncertainties: smaller than PDF uncertaintiesDiscussions on the impact to PDF in a different talk
CTEQ6.5M PDFspT (GeV)see also, Inclusive jets with Kt, CDF, Phys. Rev. D 75, 092006.January 18, 20109Strong Coupling ConstantFrom 22 (out of 110) inclusive jet cross section data points at 50 < pT < 145 GeV/c
NLO + 2-loop threshold corrections MSTW2008NNLO PDFs
Extend HERA results to high pT
3.5-4.2% precisionPhys. Rev. D 80, 111107CDF results in Phys. Rev. Lett. 88, 042001January 18, 201010Dijet Mass SpectrumTest pQCD predictionsSensitive to new particles decaying into dijets: excited quarks, heavy gluons, techni-, etc
Dijets with jets |yjet| 20 GeV and || < 1.5
WHlbb search
Success of NLO QCD. Awaiting for differential measurements.
arXiv: 0909.1505January 18, 201038
UE in Jet and Drell-Yan ProductionJet production: Transverse region sensitive to UEHigh statistics jet sampleStudies in various dijet topologiesDY production:Transverse and toward regions (excluding lepton-pairs) sensitive to UECleaner environment (Z/* carries no color)Limited statistics
Leading jet / Z Direction
jet, , ZjetTransverse plane- PlaneUnderlying Event: everything except hard scatter
January 18, 201039UE in DY and Jet ProductionComparisons of three regionsAway region pT density goes up with lepton-pair pT, while the transverse and toward region pT densities are mostly flat with lepton-pair pT
Comparisons between jet and DY Similar trend in jet and DY events: UE universality?Tuned Pythia describe data reasonably well.
There are many more plots for UE in jet and Drell-Yan production correctedto hadron level: Very important for MC generator tuning/development
January 18, 201040
Double Parton using +3 JetsStudy interactions of two parton pairs in single proton:Insight to parton spatial distributions in the protonBackground to other process especially at high luminosities
Main backgroundsignalDP = j jj/eff
eff : effective interaction region(Large eff: partons more uniformly distributed)
4040January 18, 201041Double Parton Scattering
eff = 15.11.9 mb(consistent with previous CDF results.)Calculated for the pair that gives the minimum value of S:
D0 Note 5910
Jet #1 Direction
Toward
Transverse
Transverse
Away
-1
+1
2
0
Leading
Jet
Transverse
Region
Toward Region
Transverse
Region
Away Region
Away Region