qcd and electroweak results from the tevatron nikos varelas university of illinois at chicago...

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

http://www-cdf.fnal.gov/physics/new/qcd/QCD.html

http://www-cdf.fnal.gov/physics/ewk/

http://www-d0.fnal.gov/Run2Physics/WWW/results/qcd.htm

http://www-d0.fnal.gov/Run2Physics/WWW/results/ew.htm


Proton Anti-Proton Collisions


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

CDF

DØ


DØ Detector

Multipurpose DetectorSilicon Microstrip and

Scintillating Fiber Tracker2-T Superconducting SolenoidPreshower DetectorsEM and Hadronic Calorimeters

Uranium – Liquid ArgonCoverage: | |<4.2 h ( ~2q 0)Finely segmentedCompensating e/ ~1p

Muon Detectors


CDF Detector

Multipurpose DetectorSilicon Vertex DetectorCentral Outer Tracker (Drift

Chambers)TOF1.4-T Superconducting SolenoidEM (Pb/Scint) and Had (Fe/Scint)

CalorimetersCoverage: | |<3.6h

Muon DetectorsGas Cherenkov

3.7<| |<4.7h


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)


High-pT Jet ProductionConfront pQCD calculations

NLO predictions reliable @ ±10% level

Sensitive 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


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

N

L

EE

√s = 0.5 – 0.6 TeV Cone jet clustering PT range: 20 – 200 GeV

Comparison to LO QCD Compositeness LC > 0.8 TeV

d

dPdx f x dx f x

d

dPTa

a ba A a b b B b

T

,/ /( , ) ( , )

d

dPab cd M

T

s

N

N

N

( )

( )

2

State of art: 3-jet production @ NLO(Next-to-Leading Order ~O(as

4))

T

T

jet

TT

T

ELdtE

N

ddE

dEdd

E vs.

1 2


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


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)

s

0041.00048.01161.0)(

Zs M

s


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 GeV

Axigluon, flavor-universal coloron

260 - 1250 GeV

E6 Diquark

290 - 630 GeV

Color-octet techni-r 260 - 1100 GeV

W’ : 280 - 840 GeV

Z’ : 320 - 740 GeV


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% mR,F variation

arXiv: 1002.4594 (2010)


Dijet Angular Distributions

dN/dc sensitive to contact interactions

Rutherford

LO QCD

with contact term

ccosq*

From cosq* variable to c

e y*2

212

1* yyy

212

1yy

boosty

222

ˆ1

)(ts

2

22 ˆ

ˆ1

)(u

ts 2

2

ˆ

u

d ~ [ s QCD + Interference + Compositeness ]

q q

q q

s

Mjj ~ Λ

ds ~ 1/(1-cosq*)2 angular distribution

ds ~ (1+cosq*)2 angular distribution


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

2515

101

CDF: L > 2.4 TeV for l = -1


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 DR > 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


R3/2: 3-Jet/2-Jet Cross Section Ratio

R3/2 = s3-jet / s2-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, DRjet-jet > 1.4

Measurement of R3/2(pTmax, pTmin) vs. pTmax (i.e. leading jet pT)


R3/2= s3-jet / s2-jet

Data can discriminate against PYTHIA tunes Reasonable agreement with tune BW Disagreement with tunes A & DW

SHERPA describes the data well


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)


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)


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


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


Di-Photon Production

Accepted by PLB asXiv:1002.4917 (2010)

2 photons with pT > 21(20) GeV

|yg|<0.9, DR( ,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


Di-Photon Results

Discrepancies between data and theoretical predictions


Di-Photon Results

Diphoton results w/ 5.4 fb-1 show discrepancies with predictions


W/Z + Jets CDF Results (since PLHC2008)

Z(mm) + 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 s(Z+b jet)/s(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)


Z + Jets

PRL 100, 102001 & update

1st and 2nd leading jet pTJet multiplicity

Good agreement with NLO MCFM


Z(ee) + (1, 2, 3) Jets: pT SpectraNormalize to inclusive Z production compare to MC Event Generators

29

Parton-shower MCs disagree in shape & normalization

ME + Parton-shower generators describe shape better

PLB 669, 278 (2008) PLB 678, 45 (2009)

1st jet 2nd jet 3rd jet


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 mm 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: s(Z+b)/s(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


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)

pT

e, m > 20 GeV/c, |hem| < 1.1, pT

n > 25 GeV/cp

Tbjet > 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


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 s(W+c jet)/s(W+jets) cancels many systematic uncertainties

pTjet>20 GeV, |hjet|<2.5

Preliminary Measurement (4.3 fb-1) s(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)


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 ggm+m- : 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 ds/dt in Elastic ppbar

Scattering: Preliminary High Mass Exclusive Dijet Production: Preliminary Double Parton Interactions in g+3 Jet Events: PRD 81, 052012 (2010)


Scattering of two parton pairs in a collision

seff: a measure of effective size of interaction region Contains information on the spatial

distribution of partons Uniform Large seff small sDP

Clumpy Small seff large sDP

Double Parton in g + 3 Jets

Double parton scattering can be background to many rare processes


In agreement with previous CDF measurements:

PRD 47, 4857 (1993); PRL 79, 584 (1997)

Double Parton: Results

Average seff = 16.4 ± 0.3(stat) ± 2.3 (syst) mb

DØ: PRD 81, 052012 (2010)


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 density

Average charge particle pT Tevatron measurements are used to tune MC

event generators

Jet #1 Direction

“Toward”

“Transverse” “Transverse”

“Away”

-1 +1

2

0

Leading Jet

Toward Region

Transverse Region

Transverse Region

Away Region

Away Region


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


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) Df distribution of tracks from leading pT trackRegions: |h|< 1, |h|<2, same/opposite sides

Compare data to Pythia predictions


Charged Particle Correlations: Results

Sensitivity to Pythia tunes Further studies are under way


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


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 ds/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)


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* mm 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


Electroweak Results


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

ds/dy data compared to NLO/NNLO + variety of PDFs

Previous measurement:DØ: PRD 76, 012003 (2007)

CDF: arXiv: 0908.3914 (2009)


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


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


W Charge Asymmetry: A(|hm|) W mn, 4.9 fb-1 2.3M reconstructed W decayspT(m) > 20 GeV, | ( )h m |<2, MET>20 GeV

Backgrounds: multijets, Wtn, Zmm, Z tt

Measure A(| ( )|h m ) in 3 pT(m) bins

pT(m) > 20 GeV

20 < pT(m) < 35 GeV

pT(m) > 35 GeV

Results compared to RESBOS+CTEQ6.6M

Reasonable agreement with predictions for the inclusive sample

Disagreement when data are divided into pT(m) bins


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)


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


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**

**

FBA

llZqq */

**2*

cos)cos1(cos

BA

d

d


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


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


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


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+l /n nn)ZZ(4l)


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)


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 s effect):DØ: PRL102, 161801 (2009)

Charged lepton required: WW, WZUse Mjj and Matrix Element Methods

5.4 σ

Previous resultCDF: PRL 103, 091803 (2009)


ZZ Production

ZZ4 leptonsCDF’s new result based on 4.8 fb-1

5 events observed Previous results:

CDF PRL 100, 201801 (2008)DØ PRL 101, 171803 (2008)

sZZ = 1.56+0.80

-0.63(stat)±0.25(sys) pb

5.7 σ

SM 1.4 ± 0.1 pb


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


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


AcknowledgementsThanks to: Lee Saywer, Markus Wobisch, Heidi

Schellman, Mark Lancaster, Kenichi Hatakeyama, Sasha Pranko, Dmitry Bandurin, Larry Nodulman


Backup Slides


Quark Compositeness: For the composite interactions can be represented by contact

terms:

Eichten, Lane, Peskin, PRL 50, 811 (1983) =L ∞ point-like quarks =L finite 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 qqqqg

L

2

2

2

s

q q

q q


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


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

LOQCD

NLOQCDLO

NPLOQCD

LONPNLO

QCDNLONP


3-Jet Mass: Data vs pQCD Rapidity Dependence

pTJet3 Dependence

Well described by NLO pQCD


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


Z(mm) + Jets: Rapidity, Azimuth

s(Z+jet) vs. Df(Z,jet) s(Z+jet) vs. Dy(Z,jet)

PLB 682, 370 (2010)

qcd and electroweak results from the tevatron nikos varelas university of illinois at chicago...

Documents

s3jet s2jet data

leading jet pt

cjet measure

bquark jet production

inclusive photon production

d results

tev cdfd

photon processes