qcd and electroweak results from the tevatron nikos varelas university of illinois at chicago
DESCRIPTION
QCD and Electroweak Results from the Tevatron Nikos Varelas University of Illinois at Chicago http://www.uic.edu/~varelas for the DØ and CDF Collaborations Physics at LHC DESY June 10, 2010. 21. QCD EWK. Outline. Tevatron Run II and CDF&DØ Detectors High-P T Jets W/Z/ g + Jets - PowerPoint PPT PresentationTRANSCRIPT
QCD and Electroweak Results from the Tevatron
Nikos VarelasUniversity of Illinois at Chicago
http://www.uic.edu/~varelas
for the DØ and CDF Collaborations
Physics at LHCDESY
June 10, 2010
QCDEWK
21
2PLHC2010 - June 10, 2010N. Varelas
Tevatron Run II and CDF&DØ DetectorsHigh-PT JetsW/Z/g + JetsMultiple Parton InteractionsMinimum Bias/Underlying Event StudiesElectroweak Results Summary
Outline
http://www-cdf.fnal.gov/physics/new/qcd/QCD.htmlhttp://www-cdf.fnal.gov/physics/ewk/
http://www-d0.fnal.gov/Run2Physics/WWW/results/qcd.htmhttp://www-d0.fnal.gov/Run2Physics/WWW/results/ew.htm
3PLHC2010 - June 10, 2010N. Varelas
Proton Anti-Proton Collisions
4PLHC2010 - June 10, 2010N. Varelas
Tevatron Complex Run I 1992-1996 ECM = 1.8 TeV ~120 pb-1 (0.63 TeV ~600 nb-1)
Run IIA 2002-2005 ECM = 1.96 TeV ~ 1.5 fb-1
Run IIB 2006- ECM = 1.96 TeV ~ 7.5 fb-1
Main Injector & Recycler
Tevatron
Chicago
p source
Booster
p
p
p p 1.96 TeV
CDFDØ
5PLHC2010 - June 10, 2010N. Varelas
DØ Detector Multipurpose Detector
Silicon Microstrip and Scintillating Fiber Tracker
2-T Superconducting SolenoidPreshower DetectorsEM and Hadronic Calorimeters
Uranium – Liquid ArgonCoverage: |h|<4.2 (q~20)Finely segmentedCompensating e/p~1
Muon Detectors
6PLHC2010 - June 10, 2010N. Varelas
CDF Detector Multipurpose Detector
Silicon Vertex DetectorCentral Outer Tracker (Drift
Chambers)TOF1.4-T Superconducting SolenoidEM (Pb/Scint) and Had (Fe/Scint)
CalorimetersCoverage: |h|<3.6
Muon DetectorsGas Cherenkov
3.7<|h|<4.7
7PLHC2010 - June 10, 2010N. Varelas
Tevatron Luminosity
Delivered ~9 fb-1
Recorded ~8 fb-1
8N. Varelas PLHC2010 - June 10, 2010
High-pT JetsCDF Results (since PLHC2008)
Search for Quark Substructure in the Angular Distribution of Dijets: Preliminary
Inclusive Jet Production: PRD 78, 052006 (2008) Dijet Production: PRD 79, 112002 (2008)
DØ Results (since PLHC2008) Three-Jet Mass Cross Section: Preliminary Ratio of Multi-Jet Cross Sections: Preliminary Dijet Invariant Mass Cross Section: submitted to PLB Determination of as: PRD 80, 111107 (2009) Dijet Angular Distributions and Searches for Quark Compositeness
and Extra Spatial Dimensions: PRL 103, 191803 (2009)
9PLHC2010 - June 10, 2010N. Varelas
High-pT Jet ProductionConfront pQCD calculations
NLO predictions reliable @ ±10% levelSensitive to dynamics, PDFs, as
Reach to high-x gluons (x,Q2) reachxT
Sensitivity to new physics (e.g., quark substructure, new particles decaying into jet final states, extra dimensions, ...)
Large kinematic reach
10PLHC2010 - June 10, 2010N. Varelas
Inclusive Jets – The Old Days
Uncertainties ~ 70% on CS: ±50% accept./jet corr (smearing) ±40% calib ±10% aging ±15% LumLC > 400 GeV “Exp and theo. Uncerts. taken in to account”
UA1 1986Inclusive Jet CS
UA2 1991 Inclusive Jet CS
Uncertainties ~ 32% on CS: ±25% model dep. (fragmentation) ±15% jet alg/analysis params ±11% calib ±5% LumLC > 825 GeV “...include sys. effects which could distort the CS shape”
bin in the jets of #Luminosity inst.sizebin
efficiencyselection sizebin
jet
TT
NL
EEhh
√s = 0.5 – 0.6 TeV Cone jet clustering PT range: 20 – 200 GeV Comparison to LO QCD Compositeness LC > 0.8 TeV
ddP
dx f x dx f xddPT
aa b
a A a b b B bT
,/ /( , ) ( , )
ddP
ab cd MT
s
N
N
N
( )
( ) a p
2
State of art: 3-jet production @ NLO(Next-to-Leading Order ~O(as
4))
TT
jet
TT
T
ELdtE
NddE
dEddE
vs. 1 2
hhh
h
11PLHC2010 - June 10, 2010N. Varelas
Inclusive Jet Cross Section
steeply falling pT spectrum: 1% error in jet energy calibration 5—10% (10—25%) central (forward) x-section
pT (GeV) Provide Input to PDF: MSTW2008 uses CDF and DØ results Data prefer lower gluon PDF at high-x
DØ: PRL 101, 062001 (2008)CDF: PRD 78, 052006 (2008)
CTEQ6.5M PDFs
12PLHC2010 - June 10, 2010N. Varelas
Inclusive jet cross section is sensitive to as as is determined from 22 inclusive cross section data
points at the range 50<pT<145 GeVMSTW2008NNLO PDFs
Most precise determination of as from a hadron collider
The Strong Coupling Constant
jet
jet
PRL 101, 062001 (2008)
sa
0041.00048.01161.0)(
-Zs Ma
sa
13PLHC2010 - June 10, 2010N. Varelas
Dijet Mass Distribution Select jets with |y|<1.0Sensitive to new particles
decaying to dijets
PRD 79, 112002 (2009)
Data described by NLO pQCDNo indications for resonances
Exclusions mass ranges: excited quarks 260 - 870 GeVAxigluon, flavor-universal coloron 260 - 1250 GeVE6 Diquark
290 - 630 GeVColor-octet techni-r
260 - 1100 GeVW’ : 280 - 840 GeVZ’ : 320 - 740 GeV
14PLHC2010 - June 10, 2010N. Varelas
Dijet Mass Cross Sections Unfolded Cross Sections Measurement in six |y|max regions
Jet Energy Scale is the leading source of data systematic uncertainty
CTEQ6.6 prediction too high MSTW2008 consistent w/ data
5-15% uncertainty 10-15% R,F variation
arXiv: 1002.4594 (2010)
15PLHC2010 - June 10, 2010N. Varelas
Dijet Angular Distributions
dN/dc sensitive to contact interactions
Rutherford
LO QCDwith contact term
ccosq*
From cosq* variable to c
e y*2c
2121* yyy -
2121 yyboosty
222
ˆ1)(ts a 2
22 ˆ
ˆ1)(
Lu
ts a2
2
ˆ
Lu
d ~ [ QCD + Interference + Compositeness ]q q
q q
L<<s
Mjj ~ Λ
d ~ 1/(1-cosq*)2 angular distribution
d ~ (1+cosq*)2 angular distribution
16PLHC2010 - June 10, 2010N. Varelas
Dijet Angular: Results DØ: PRL 103, 191803 (2009)
Compositeness (L): ~2.8 – 3 TeV ADD LED (GRW, Ms): ~1.6 – 1.7 TeV TeV-1 Extra Dim (MC): ~1.6 – 1.7 TeV
1.1/fb, Mjj=550-950 GeVCDF Preliminary
2515101
cc
CDF: L > 2.4 TeV for l = -1
17PLHC2010 - June 10, 2010N. Varelas
3-Jet Mass Cross Section First measurement of 3-jet cross
section at Tevatron Require at least 3 jets in the event
Jet1 pT > 150 GeV Jet 2,3 pT > 40 GeV Jets separated by R > 1.4 = 2*Rcone
Measurement performed in: rapidity intervals |y| < 0.8, 1.6, 2.4 pT ranges of the 3rd jet: pT
Jet3 > 40, 70, 100 GeV
Compared data to NLO pQCD
Rapidity DependencepTJet3 Dependence
18PLHC2010 - June 10, 2010N. Varelas
R3/2: 3-Jet/2-Jet Cross Section Ratio
R3/2 = 3-jet / 2-jet =
SS
...
... R3/2 : probability to find a third jet in an inclusive dijet event Sensitive to high order radiation and as Almost independent of PDFs
Use inclusive n-jet (n=2,3) sample with n (or more) jets above pTmin |yjet| < 2.4, Rjet-jet > 1.4 Measurement of R3/2(pTmax, pTmin) vs. pTmax (i.e. leading jet pT)
19PLHC2010 - June 10, 2010N. Varelas
R3/2= 3-jet / 2-jet
Data can discriminate against PYTHIA tunes Reasonable agreement with tune BW Disagreement with tunes A & DW
SHERPA describes the data well
20N. Varelas PLHC2010 - June 10, 2010
Direct Photons CDF Results (since PLHC2008)
Prompt Diphoton Production: Preliminary Photons and b-quark Jet Production: PRD 81, 052006 (2010) Inclusive Photon Production: PRD 80, 11106 (2009)
DØ Results (since PLHC2008) Direct Photon Pair Production: Accepted by PLB Photon + Heavy Flavor Production: PRL 102, 192002 (2009)
21PLHC2010 - June 10, 2010N. Varelas
Photon processes: Annihilation Compton
Also fragmentation contributes But suppressed with isolation
Directly sensitive to hard scatter
Important for QCD studies, detector calibration, gluon PDFs, background to new physics
Challenging measurementLarge QCD jet background
Observable: isolated photons
Direct Photon ProductionDiphotons
(all quark/anti-quarksubprocesses)
22PLHC2010 - June 10, 2010N. Varelas
Inclusive Photon Cross Section
PRD 80, 11106 (2009)
Similar effect observed: PLB 639, 151 (2006)
Data/theory: shape discrepancies at low-pT
Experimental and theory uncertainties ~ PDF uncertainty No PDF sensitivity yet
23PLHC2010 - June 10, 2010N. Varelas
Photon + HF Jet Production
DØ: PRL 102, 192002 (2009)CDF: PRD 81, 052006 (2010)
pTg (GeV)
Sensitive to HF-content of photon Photon pT : 30 – 150 GeV Rapidities: |yg|<1.0, |yjet|<0.8 0.01<x<0.3 b,c, gluon PDF Photon+b:
Agreement over full pT range Photon+c:
Agree only at pT<50 GeV Using PDF w/ intrinsic charm (IC)
improves the theory behavior vs pT
g+b
g+c
24PLHC2010 - June 10, 2010N. Varelas
Di-Photon Production
Accepted by PLB asXiv:1002.4917 (2010)
2 photons with pT > 21(20) GeV |yg|<0.9, R(g,g)>0.4, pT(gg)<M(gg) Data are compared to RESBOS,
DIPHOX, PYTHIA
DATA 10938gg 7307 +/- 312
g+jet 1791+/- 411
Dijet 1679+/- 281
Z/g* ->ee 161+/- 10
25PLHC2010 - June 10, 2010N. Varelas
Di-Photon Results
Discrepancies between data and theoretical predictions
26PLHC2010 - June 10, 2010N. Varelas
Di-Photon Results
Diphoton results w/ 5.4 fb-1 show discrepancies with predictions
27N. Varelas PLHC2010 - June 10, 2010
W/Z + Jets CDF Results (since PLHC2008)
Z() + Jets: Preliminary pT Balance in Z+Jet Events: Submitted to NIM W + Charm: Preliminary W + b-Jet: PRL 104, 131801 (2010) Z + b-Jet: PRD 79, 052008 (2009)
DØ Results (since PLHC2008) Measurement of the (Z+b jet)/(Z+jet): Preliminary Z/g+jet Angular Distributions: PLB 682, 370 (2010) Differential Cross Sections of Z/g+jets : PLB 678, 45 (2009) Differential Z/g+jet Cross Sections: PLB 669, 278 (2008)
28PLHC2010 - June 10, 2010N. Varelas
Z + Jets
PRL 100, 102001 & update
1st and 2nd leading jet pTJet multiplicity
Good agreement with NLO MCFM
29PLHC2010 - June 10, 2010N. Varelas
Z(ee) + (1, 2, 3) Jets: pT SpectraNormalize to inclusive Z production compare to MC Event Generators
29
Parton-shower MCs disagree in shape & normalizationME + Parton-shower generators describe shape better
PLB 669, 278 (2008) PLB 678, 45 (2009)
1st jet 2nd jet 3rd jet
30PLHC2010 - June 10, 2010N. Varelas
Z + b jet Z+b probes the b-quark PDF and
provides an important test of pQCD Background for many channels: ZH,
top, SUSY, …
Analysis combines Zee and channels
At least one jet with pT>20 GeV, |h|<1 2 electrons (muons)
pT>15 GeV (10 GeV), |h|<2.5 (2.0)Measurement: (Z+b)/(Z+j) =
0.01760.0024(stat)0.0023(sys)Good agreement with NLO QCD: 0.0180.004
Previous measurements: DØ: PRL 94, 161810 (2005)
CDF: PRD 79, 052008 (2009)
2,
22ZTZ pmQ
31PLHC2010 - June 10, 2010N. Varelas
W + b jet Important process from many
searches at Tevatron and LHC Invariant mass of charged particles
associated with the secondary vertex is used to discriminate between the possible jet flavors to yield the b-jet fraction
CDF: PRL 104, 131801 (2010)
pTe, > 20 GeV/c, |he| < 1.1, pT
n > 25 GeV/cpT
bjet > 20 GeV, |hbjet| < 2.0
σ b-jets (W+b-jets) BR(W → l v) = 2.74 ± 0.27 (stat) ± 0.42(syst) pb⋅
All predictions are lower than the measurement: Pythia: 1.10 pb, ALPGEN: 0.78 pb, NLO: 1.22±0.14 pb
32PLHC2010 - June 10, 2010N. Varelas
W + Charm Probes s-content on proton
g+s ~ 90%, g+d ~ 10% At Tevatron W+c is ~5% of the inclusive
W+1 jet cross section with pTjet>10 GeV
Charge correlation of leptons used in event selection
Use soft lepton tagger +NN for c-jet
Measure of the ratio of (W+c jet)/(W+jets) cancels many systematic uncertainties
pTjet>20 GeV, |hjet|<2.5
Preliminary Measurement (4.3 fb-1) (Wc)BR(W lv) = 33.7 ± 11.4 (stat) ± 7.3 (syst)
pbTheory prediction @NLO (MCFM): 16.5 ± 4.7 pb
DØ: PLB 666, 23 (2008)
Previous CDF: PRL 100, 091803 (2008)
33N. Varelas PLHC2010 - June 10, 2010
Soft QCD CDF Results (since PLHC2008)
Hyperons in Min. Bias Events: Preliminary Diffractive W and Z Production: Preliminary KT Distributios of Particles in Jets: PRL 102, 232002 (2009) Underlying Event in Drell-Yan Production: Submitted to PRD Exclusive Charmonium Production and gg- : PRL 102, 242001 (2009) Search for Exclusive Z-Boson Production and Observation of High Mass
pp →pγγp →pl+l-p : PRL 102, 222001 (2009)
DØ Results (since PLHC2008) Study of Phi and Eta Correlations in MB Events: Preliminary Measurement of the Differential Cross Section d/dt in Elastic ppbar
Scattering: Preliminary High Mass Exclusive Dijet Production: Preliminary Double Parton Interactions in g+3 Jet Events: PRD 81, 052012 (2010)
34PLHC2010 - June 10, 2010N. Varelas
Scattering of two parton pairs in a collision
eff: a measure of effective size of interaction region Contains information on the spatial
distribution of partons Uniform Large eff small DP Clumpy Small eff large DP
Double Parton in g + 3 Jets
Double parton scattering can be background to many rare processes
35PLHC2010 - June 10, 2010N. Varelas
In agreement with previous CDF measurements: PRD 47, 4857 (1993); PRL 79, 584 (1997)
Double Parton: Results
Average eff = 16.4 ± 0.3(stat) ± 2.3 (syst) mbDØ: PRD 81, 052012 (2010)
36PLHC2010 - June 10, 2010N. Varelas
The “underlying event” consists of the “beam-beam remnants” and of particles arising from soft or semi-soft multiple parton interactions (MPI)
Underlying event is not the same as a minimum bias event
The Underlying Event
Hard Scattering
PT(hard)
Outgoing Parton
Outgoing Parton
Initial-State Radiation
Final-State Radiation
Hard Scattering
PT(hard)
Outgoing Parton
Outgoing Parton
Initial-State Radiation
Final-State Radiation
Proton AntiProton
Underlying Event Underlying Event
Proton AntiProton
Underlying Event Underlying Event
“Hard Scattering” Component “Jet”
“Jet”
“Underlying Event”
“Jet”
Define three regions:“toward”“away”“transverse”
Sensitive to UEStudy
charged particle multiplicitypT and ET sum densityAverage charge particle pT
Tevatron measurements are used to tune MC event generators
Jet #1 Direction
“Toward”
“Transverse” “Transverse”
“Away”
-1 +1
2p
0 h
Leading Jet
Toward Region
Transverse Region
Transverse Region
Away Region
Away Region
37PLHC2010 - June 10, 2010N. Varelas
Use the direction of the lepton pair per event to define the three regions
Correct observables to particle levelComparison of distributions
between jets and DY
UE in Drell-Yan and Jet Production
CDF: Submitted to PRD arXiv: 1002.3146
38PLHC2010 - June 10, 2010N. Varelas
Selection of MB Sample: Trigger on dimuon events Then require one or more
Minimum Bias primary vertexAt least 0.5 cm away from
triggered PVWithin 20 cm from z=0With at least 5 tracks
Charged Particle Correlations in MB Events
Observable: (background subtracted, normalized) distribution of tracks from leading pT trackRegions: |h|< 1, |h|<2, same/opposite sides
Compare data to Pythia predictions
39PLHC2010 - June 10, 2010N. Varelas
Charged Particle Correlations: Results
Sensitivity to Pythia tunes Further studies are under way
40PLHC2010 - June 10, 2010N. Varelas
pT differential cross section of hyperons with |h|<1Λ0pπ, Ξ±Λ0π±, Ω±Λ0K±
Use Minimum Bias sample
Hyperon Production in Min. Bias
Cross section drops by 7 for each s quark
41N. Varelas PLHC2010 - June 10, 2010
Electroweak CDF Results (since PLHC2008)
ZZ Production: Preliminary Z+g Production: Preliminary Anomalous Triple Gauge-Boson Coupling Limits: Preliminary Search for W pg : Preliminary Measurement of Z Forward-Backward Asymmetry: Preliminary d/dy Distribution of Drell-Yan Dielectron Pairs: Submitted for publication W Charge Asymmetry and Comparison between CDF and DØ Results:
Preliminary Update on WW/WZ Production (hadronic): Preliminary First Observation of Vector Boson Pairs in a Hadronic Final State at the
Tevatron Collider: PRL 103, 091803 (2009) Measurement of the WW+WZ Production Cross Section using Lepton+Jets
Final State: PRL 104, 101801 (2010)
42N. Varelas PLHC2010 - June 10, 2010
Electroweak DØ Results (since PLHC2008)
W Charge Asymmetry (muon channel): Preliminary Anomalous Charged Trilinear Gauge-Boson Couplings From Diboson Production: Preliminary Measurement of the Normalized Z/g* pT Distribution: Submitted to PLB Direct Measurement of the W Boson Width: PRL 103, 231802 (2009) Evidence of WW+WZ Production with Lepton+Jets Final States: PRL 102, 161801 (2009) Measurement of Trilinear Gauge Boson Couplings from WW + WZ → lνjj Events: PRD 80, 053012 (2009) Measurement of the WW Production Cross Section with Dilepton Final States and Limits on Anomalous
Trilinear Gauge Couplings: PRL 103, 191801 (2009) Measurement of the WZ→lνll Cross Section and Limits on Anomalous Triple Gauge Boson Couplings:
Submitted to PLB Measurement of the σ(pp → Z + X)Br(Z → τ+τ−): PLB 670, 292 (2009) Search for a Scalar or Vector Particle Decaying into Zγ: PLB 671, 349 (2009) Measurement of the Zγ → ννγ Production Cross Section and Limits on Anomalous ZZγ and Zγγ
Couplings: PRL 102, 201802 (2009)
Tevatron Results (since PLHC2008) CDF and DØ Results on the W Width: Preliminary CDF and DØ Results on the W Mass: Preliminary
43PLHC2010 - June 10, 2010N. Varelas
Electroweak Results
44PLHC2010 - June 10, 2010N. Varelas
Z Rapidity Sensitive to PDFs
At LO Large dilepton rapidity |y|
probes PDFs of the two colliding partons at large and low x
Sample: Z ee, 2.1 fb-1
d/dy data compared to NLO/NNLO + variety of PDFs
Previous measurement:DØ: PRD 76, 012003 (2007)
CDF: arXiv: 0908.3914 (2009)
45PLHC2010 - June 10, 2010N. Varelas
W Charge Asymmetry u quarks carry more
momentum than d quarksW+ preferentially boosted
along the proton direction
Due to V-A interaction the charge lepton from W decay heads backwards in the W frame
Sensitive to PDFsPrecision of data can
probe inconsistencies with latest PDFs
46PLHC2010 - June 10, 2010N. Varelas
W Charge Asymmetry
W+
P (u) P (d)
Probes the u(x)/d(x) PDF ratio x1 and x2 are the momentum
fractions in the proton and anti-proton
Traditionally the Lepton Asymmetry A(|hlepton|) is used Experimentally very well defined
47PLHC2010 - June 10, 2010N. Varelas
W Charge Asymmetry: A(|h|) W n, 4.9 fb-1 2.3M reconstructed W decayspT() > 20 GeV, |h()|<2, MET>20 GeVBackgrounds: multijets, Wtn, Z,
Ztt Measure A(|h()|) in 3 pT() bins
pT() > 20 GeV20 < pT() < 35 GeVpT() > 35 GeV
Results compared to RESBOS+CTEQ6.6M
Reasonable agreement with predictions for the inclusive sample
Disagreement when data are divided into pT() bins
48PLHC2010 - June 10, 2010N. Varelas
Direct Measurement of A(|yW|) Reconstruct yW distribution with
MW constraint Weight both yW solutions with
probability given by production and decay
Iterate since weight depends on yW
Method documented in A.Bodek et al., PRD 77, 111301(R) (2009).
Results compared to CTEQ6.1M (NLO) and MRST2006 (NNLO) PDFs
Experimental precision is much better than the theoretical uncertainty
CDF: PRL 102, 181801 (2009)
49PLHC2010 - June 10, 2010N. Varelas
Comparison of DØ and CDF Results CDF has measured the electron asymmetry from the published
W asym. data sample and compared the results with the DØ muon and electron data – with a higher pT cut of 25 GeV
DØ and CDF lepton asymmetry results are consistent with each other, but disagree with theoretical predictions for binned lepton pT
50PLHC2010 - June 10, 2010N. Varelas
Z Forward-Backward Asymmetry The presence of both vector and axial-vector couplings in the gives rise to an asymmetry (AFB) in the polar angle
(q *) of the negatively charged lepton momentum relative to the incoming quark momentum in the lepton pair rest frame
Sensitive to sin2qW and possible new physics (Z’)
)0(cos)0(cos)0(cos)0(cos
**
**
<<-
qqqq
FBA
- llZqq */g
**2* cos)cos1(
cosqq
q BA
dd
51PLHC2010 - June 10, 2010N. Varelas
Z Forward-Backward Asymmetry
Previous: CDF: PRD 71, 052002 (2005)
With 8 fb-1 of data expect to extract sin2qW from a CDF-DØ combined AFB using electrons and muons with precision comparable to current world average
DØ: PRL 101, 191801 (2008), 1.1 fb-1
52PLHC2010 - June 10, 2010N. Varelas
W Mass Update DØ: PRL 103, 141801 (2009),1 fb-1
CDF: PRD 77, 112001 (2008), 0.2 fb-1
PRL 99, 151801 (2007), 0.2 fb-1
Based on mT, pT(l), MET
DØ Uncertainties on Mw (MeV)
total Tevatron uncertainty of 31 MeV is now smaller than that of 33 MeV from LEPII
World average is now 80.399 0.023 GeV
DØ: single most precise measurement
53PLHC2010 - June 10, 2010N. Varelas
W Width Update Exploit high tail of MT(W) distribution
DØ: PRL 103, 231802 (2009), 1 fb-1 CDF: PRL 100, 071801 (2008), 0.35 fb-1
World average is now 2,085 42 MeV
Mass Width
54PLHC2010 - June 10, 2010N. Varelas
Diboson Production Exploit the non-Abelian structure
of SM: probe trilinear gauge boson couplings
Sensitive to new physics: anomalous couplings could enhance production rate
Background to searches (Higgs, SUSY)
Small cross sections All now observed w/ ~5 fb -1
Recent results:WW/WZ/ZZ (jj+ln/nn)ZZ(4l)
55PLHC2010 - June 10, 2010N. Varelas
WW/WZ/ZZ: Hadronic Final State All Hadronic Final State:
Missing ET + dijet signatureW (nl:MET) + W/Z (qq:dijet)Z (nn:MET) + W/Z (qq:dijet)
First observation of diboson production in all hadronic final state
5.3 σ
σ = 18.0 2.8(stat) 2.6(syst) pbσ (theory) = 16.8 0.5 pb
Previous CDF: PRL 103, 091803 (2009)
56PLHC2010 - June 10, 2010N. Varelas
WW/WZ: l+jets Final State
5.2 σ
σ = 18.1 ± 3.3stat ± 2.5sys pb (Mjj)σ = 16.5 +3.3
-3.0stat ± 3.5sys pb (ME)SM = 16.8 0.5 pb
Previous result (4.4 effect):DØ: PRL102, 161801 (2009)
Charged lepton required: WW, WZUse Mjj and Matrix Element Methods
5.4 σ
Previous resultCDF: PRL 103, 091803 (2009)
57PLHC2010 - June 10, 2010N. Varelas
ZZ Production ZZ4 leptons
CDF’s new result based on 4.8 fb-1
5 events observed Previous results:
CDF PRL 100, 201801 (2008)DØ PRL 101, 171803 (2008)
ZZ = 1.56+0.80
-0.63(stat)±0.25(sys) pb
5.7 σ
SM 1.4 ± 0.1 pb
58PLHC2010 - June 10, 2010N. Varelas
Rare W Decays g
W-p-p-
g
W-
Rare radiative decays of W bosons to a g and charged p are predicted to occur in the SM with a branching fraction of 10-6 – 10-8
Offer clean final state: enhanced by BSM physics
206 candidate events in signal region: 75 < Mpg < 85 GeV
59PLHC2010 - June 10, 2010N. Varelas
CDF and DØ have produced many new results on QCD and EWK physics since PLHC2008 at SplitPresented results with up to ~5 fb-1 of dataExperiments have ~8 fb-1 on tape
High luminosities at Tevatron have allowed for precision measurements providing fundamental insights into perturbative and nonperturbative modelsMeasurements have reached higher precision than
theoretical predictionsWith the full Tevatron data sample we can extend the
present phase space reach and probe more rare processes which may reveal something unexpected
Final Words
60PLHC2010 - June 10, 2010N. Varelas
AcknowledgementsThanks to: Lee Saywer, Markus Wobisch, Heidi
Schellman, Mark Lancaster, Kenichi Hatakeyama, Sasha Pranko, Dmitry Bandurin, Larry Nodulman
61N. Varelas PLHC2010 - June 10, 2010
Backup Slides
62PLHC2010 - June 10, 2010N. Varelas
Quark Compositeness: For the composite interactions can be represented by contact
terms:
Eichten, Lane, Peskin, PRL 50, 811 (1983)L∞ point-like quarks Lfinite substructure of mass scale L
Large Extra Dimensions (LED) In the ADD Model:
N.Arkani-Hamed, S.Dimopoulos, G.R.Dvali, PLB 429, 263 (1998), et al.3+n spacelike dimensionsn dimensions compactified to a n-torus with radius R
R~1 mm for n=2, R~3 nm for n=3, …All SM fields are confined to a 3-dim membrane (brane) Only gravity propagates in all dimensions (bulk)
Mass hierarchy problem is solved The unification scale can be lowered to Ms~TeV
Compositeness and Large Extra Dim.
LLLLqq qqqqgL gg2
2
2L
L<<sq q
q q
63PLHC2010 - June 10, 2010N. Varelas
In the TeV-1 Extra Dimension ModelK.Dienes, E.Dudas, T.Gherghetta, Nucl. Phys. B 537, 47 (1999)A.Pomarol, M.Quirós, PLB 438, 255 (1998) I.Antoniadis, K.Benakli, M.Quirós, PLB 460, 176 (1999), et al.
Matter resides on a p-brane (spacelike dim p>3):Fermions are confined to 3-dim world SM gauge bosons can also propagate in the extra (p-3)
dimensionsSM cross sections are modified due to the exchange of virtual
Kaluza-Klein excitations ( , n=1,2,…) of the SM gauge bosons (e.g., gluons) through the ED
Compact dimension R=1/MC (MC is the compactification scale) the 95% CL limit: MC=6.6 TeV from combined LEP data
TeV-1 Extra Dimensions
222 / RnMM SMn
64PLHC2010 - June 10, 2010N. Varelas
Search for BSM Signatures BSM signatures will populate the low-c
region at high Mjj: Compositeness (scale L) Virtual exchange of KK excitations of graviton
(ADD LED scale Ms) Virtual KK excitation of gluon (TeV-1 ED scale
MC)Theory implementation:
NPSMNP MEMEME 2int ED) (TeV /1
LED) (ADD /1
(QC) /
12
4
2
-C
s
M
M
L
lLOQCD
NLOQCDLO
NPLOQCD
LONPNLO
QCDNLONP
65PLHC2010 - June 10, 2010N. Varelas
3-Jet Mass: Data vs pQCD Rapidity Dependence
pTJet3 Dependence
Well described by NLO pQCD
66PLHC2010 - June 10, 2010N. Varelas
Z(ee) + (1, 2, 3) Jets: pT Spectra
PLB 669, 278 (2008) & PLB 678, 45 (2009)
2nd jet1st jet 3rd jet
Normalize to inclusive Z production compare to pQCD @ LO / NLO
67PLHC2010 - June 10, 2010N. Varelas
Z() + Jets: Rapidity, Azimuth
(Z+jet) vs. (Z,jet) (Z+jet) vs. y(Z,jet)
PLB 682, 370 (2010)