Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production...

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vy flavor production in vy flavor production in Mario Campanelli/ Mario Campanelli/ Geneva Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and tagging Exclusive charm production in D 0 /D* Heavy flavor spectroscopy Exclusive b production in J/ψ Inclusive b-jet

Transcript of Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production...

Page 1: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Heavy flavor production inHeavy flavor production inMario Campanelli/ Mario Campanelli/

GenevaGenevaWhy studying heavy flavor production

Experimental techniques:

the Tevatron and CDF

triggering and and tagging

Exclusive charm production in D0/D*

Heavy flavor spectroscopy

Exclusive b production in J/ψ

Inclusive b-jet production

Inclusive bb

Inclusive b/γ

Page 2: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

What’s interesting in HF production at What’s interesting in HF production at colliderscolliders

kHz rates at present Tevatron kHz rates at present Tevatron energy/luminosityenergy/luminosity

High mass -> well established High mass -> well established NLO calculations, NLO calculations, resummation of log(pT/m) terms (FONLL)

New fragmentation functions from LEP data

Gluon splittingFlavor creation

Leading Order Next to Leading Order

Flavor excitationg

g

g

g

Q

Q

other radiative corrections..

Release date of PDF

bN

LO(|y

|<1)

(b

) <1994

now

Page 3: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

The TevatronThe Tevatron World’s largest hadron colliderWorld’s largest hadron collider √√s = 1.96 TeVs = 1.96 TeV Peak lum Peak lum 1.2 101.2 1032 32 cmcm-2-2 s s-1-1 1 fb1 fb-1-1 delivered to experiments delivered to experiments Analyses Analyses ~ 60-400 pb~ 60-400 pb-1-1

Collected > 800 pb-1

Delivered > 1 fb-1

Page 4: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

CDF II CDF II detectordetector

CalorimeterCalorimeter CEM lead + scint 13.4%/√ECEM lead + scint 13.4%/√Ett2%2% CHA steel + scint 75%/√ECHA steel + scint 75%/√Ett3%3%TrackingTracking (d0) = 40(d0) = 40m (incl. 30m (incl. 30m beam)m beam) (pt)/pt = 0.15 % pt (pt)/pt = 0.15 % pt

CDF fully upgraded for Run CDF fully upgraded for Run II:II:

Si & trackingSi & tracking Extended calorimeters range Extended calorimeters range L2 trigger on displaced tracksL2 trigger on displaced tracks High rate trigger/DAQHigh rate trigger/DAQ

Page 5: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

The experimental The experimental challengechallenge

b production 3-4 orders of b production 3-4 orders of magnitude smaller than magnitude smaller than ordinary QCD; selected by ordinary QCD; selected by longer lifetimelonger lifetime

c slightly higher but more c slightly higher but more difficult to isolatedifficult to isolate

impact parameter

Decay Length

Primary Vertex

Secondary Vertex

b/c

Two strategies:

•High-pt (so far): take unbiased prescaled triggers, identify b off-line

•Low-pt: use on-line impact-parameter information to trigger on hadronic decays

Page 6: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Silicon Vertex Silicon Vertex Tracker (SVT)Tracker (SVT)

On-line tracking reconstruction allows On-line tracking reconstruction allows design of specific triggers for heavy design of specific triggers for heavy flavors; widely used in low-pt physics, flavors; widely used in low-pt physics, extension to high-pt under wayextension to high-pt under way

35 m 33 m = 47 m

(resolution beam)

Page 7: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Cross section of exclusive Cross section of exclusive charm statescharm states

With early CDF data:With early CDF data: 5.8 5.80.3pb0.3pb-1-1

• Measure prompt charm meson

production cross section

• Data collected by SVT trigger

from 2/2002-3/2002

• Measurement not statistics limited

Large and clean signals:

Page 8: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Need to separate direct D and BD decay

• Prompt D point back to collision point

I.P.= 0

• Secondary D does not point back to PV

I.P. 0

Separating prompt from Separating prompt from

secondary Charmsecondary Charm

Direct Charm Meson Fractions:Direct Charm Meson Fractions:

DD00: f: fDD=86.4±0.4±3.5=86.4±0.4±3.5%%

D*D*++: : ffDD=88.1±1.1±3.9%=88.1±1.1±3.9%

DD++: f: fDD=89.1±0.4±2.8%=89.1±0.4±2.8%

DD++ss: f: fDD=77.3±3.8±2.1%=77.3±3.8±2.1%

BD tail

Detector I.P. resolution shape measured

from data in K0s sample.

Most of reconstructed charm mesons are direct

Separate prompt and secondary

charm based on their transverse

impact parameter distribution.

Prompt D Secondary D from B

Promptpeak

Page 9: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Differential Charm Meson Differential Charm Meson X-Section X-Section

Calculation from M. Cacciari and P. Nason:

Resummed perturbative QCD (FONLL)

JHEP 0309,006 (2003)

CTEQ6M PDF

Mc=1.5GeV,

Fragmentation: ALEPH measurement

Renorm. and fact. Scale: mT=(mc2+pT

2)1/2

Theory uncertainty: scale factor 0.5-2.0

PT dependent x-sections:

Theory prediction:

Page 10: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Spectroscopy with SVT Spectroscopy with SVT datasetsdatasets

Huge dataset in Huge dataset in Bs and Bs and hadronic hadronic charm, best charm, best world world spectroscopic spectroscopic measurements measurements for many statesfor many states

Page 11: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

X(3872): observationX(3872): observation The Belle observation of a mysterious The Belle observation of a mysterious

new state X(3872) in J/new state X(3872) in J/ΨΨ ππ++ππ-- pushed pushed CDF to its first confirmation. CDF to its first confirmation.

Cut on M(π π)>500 MeV: 659 candidates on 3234 background, signal seen at 11.6σ.

730 candidates, M(X) = 3871.3 ± 0.7 (stat) ± 0.4 (sys)

Г(X) = 4.9 ± 0.7 consistent with detector resolution

Page 12: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

B production B production from J/from J/ψψ

Uses Uses μμμμ trigger down to pt=0 trigger down to pt=0As for D case, measures both prompt As for D case, measures both prompt

production and b decaysproduction and b decays

Final b Final b cross cross section in section in agreemenagreement with t with NLO NLO calculatiocalculationsns

Combined variable of mass pt and impact parameter allows distinction of the two cases

Page 13: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

High-pt identification: High-pt identification: search for secondary vertexsearch for secondary vertex

For inclusive studies, instead For inclusive studies, instead of trying to identify specific of trying to identify specific b decay products, we look b decay products, we look for a secondary vertex for a secondary vertex resulting from the decay of resulting from the decay of the b mesonthe b meson

Efficiency of this “b Efficiency of this “b tagging” algorithm tagging” algorithm (around 40%) is taken (around 40%) is taken from Monte Carlo and from Monte Carlo and cross-checked with b-cross-checked with b-enriched samples (like enriched samples (like isolated leptons)isolated leptons)

Page 14: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Jet algorithms for Jet algorithms for inclusive studiesinclusive studies

JetCluJetClu PreclusteringPreclustering Uses EUses Ett, , Not Not infraredinfrared safe safe Not Not collinearcollinear

safesafe

MidPointMidPoint No preclusteringNo preclustering Uses pUses ptt, y, y Adds midpoints Adds midpoints

to original seedsto original seeds Infrared safeInfrared safe

Good jet definition– Resolve close jets– Stable, boost invariant– Reproducible in theory

– Cone based (seeded) algorithms– JetClu (RunI)– MidPoint (new RunII )

– Merging pairs of particles– Kt (recently used @ CDF)

Page 15: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

b-jet fractionb-jet fractionWhich is the real b content Which is the real b content (purity)(purity)??Extract a fraction directly from dataExtract a fraction directly from data Use shape Use shape secondary vertex masssecondary vertex mass

Different PDifferent Ptt bins to cover wide spectrum bins to cover wide spectrum Fit data to MC templatesFit data to MC templates

MonteCarlo templatesb

non-b

98 < pTjet < 106 GeV/c

Page 16: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

High pHigh ptt b jet cross b jet cross sectionsection

MidPointMidPoint R Rconecone 0.7, |Y| < 0.7 0.7, |Y| < 0.7 Pt ranges defined to have Pt ranges defined to have 99% 99% efficiencyefficiency ((97% 97% Jet05)Jet05)

Jets corrected for det effectsJets corrected for det effects

~ 300 pb-1

Pt ~ 38 ÷ 400 GeV

20 ÷ 10%

Inclusive calorimetric triggersInclusive calorimetric triggers L3 Et > x L3 Et > x (5,20,40,70,100)(5,20,40,70,100)

Page 17: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Preliminary Data/Pythia tune A ~ 1.4

As expected from NLO/LO comparison

Main sources of Main sources of systematics:systematics:

Absolute energy scaleAbsolute energy scale B-taggingB-tagging

High pHigh ptt b-jet cross b-jet cross sectionsection

Page 18: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

bb cross bb cross sectionsection

Calorimetric triggerCalorimetric trigger L3: reconstructed jet L3: reconstructed jet

EEtt>20GeV>20GeV JetCluJetClu cone 0.7 cone 0.7 Two central jets |Two central jets ||< 1.2|< 1.2

EEtt(1) > 30 GeV, E(1) > 30 GeV, Ett(2) > 20 GeV (2) > 20 GeV Energy scale corrected for Energy scale corrected for

detector effects detector effects Acceptance Acceptance

Trigger efficiency folded inTrigger efficiency folded in b tagging efficiency from datab tagging efficiency from data

Use an electron sample to Use an electron sample to increase bjets contentincrease bjets content

b fractionb fraction Fit to secondary vertex mass Fit to secondary vertex mass

templatestemplates

~ 64 pb-

1

Page 19: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

bb cross bb cross sectionsection Main Main systematicssystematics::

Jet energy scale (~20%)Jet energy scale (~20%) b tag efficiency (~8%)b tag efficiency (~8%)

UE description lowers UE description lowers Herwig predictionHerwig prediction

DataData 34.5 ± 1.8 ± 34.5 ± 1.8 ± 10.5nb10.5nb

Pythia(CTEQ5l)Pythia(CTEQ5l) 38.71 38.71 0.62nb 0.62nb

Herwig(CTEQ5lHerwig(CTEQ5l))

21.53 21.53 0.66nb 0.66nb

MC@NLOMC@NLO 28.49 28.49 0.58nb 0.58nb

Better agreement with NLO MC can be reached using a multiparton generator (JIMMY) that gives better description of underlying event. Still under investigation.

Further analyses going on using SVT-triggered multi-b datasets

Page 20: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

b/c + b/c + γγ analysis analysis Background to Susy Background to Susy

searches, will be searches, will be used used to extract used used to extract b/c Pdf’sb/c Pdf’s

No event-by-event No event-by-event photon identification photon identification possible: only possible: only statistical statistical separation based on separation based on shower shape in shower shape in electromagnetic electromagnetic calorimetercalorimeter

Pre-shower Detector (CPR)

Central Electromagnetic Calorimeter

Shower Maximum Detector (CES)

Wire Chambers

Page 21: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

Photon + b/c Photon + b/c AnalysisAnalysis

Apply further requirements off-Apply further requirements off-line:line:

|||<1.0|<1.0 jet with secondary vertexjet with secondary vertex Determine b, c, uds Determine b, c, uds

contributions contributions Subtract photon background Subtract photon background

using shower shape fitsusing shower shape fits

So far, use Et > 25 GeV Et > 25 GeV unbiased photon dataset, without jet requirements at trigger level:

Studies going on using dedicated triggers based on SVT

Page 22: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

γγb, b, γγc c resultsresults

Cross sections and ratio agree with LO predictions from MC.

This measurement still largely statistics-dominated

Page 23: Heavy flavor production in Mario Campanelli/ Geneva Why studying heavy flavor production Experimental techniques: the Tevatron and CDF triggering and and.

ConclusioConclusionsns

CDF has a broad program in heavy flavor CDF has a broad program in heavy flavor production studies (not to mention decays, production studies (not to mention decays, oscillations etc.), thanks mainly to its trackeroscillations etc.), thanks mainly to its tracker

Main limitation is trigger and bandwidth; SVT Main limitation is trigger and bandwidth; SVT allowed a large increase in low-pt b physics, allowed a large increase in low-pt b physics, high-pt studies mainly used unbiased triggershigh-pt studies mainly used unbiased triggers

SVT is being upgraded for more occupancy SVT is being upgraded for more occupancy having in mind mainly high-pt applicationshaving in mind mainly high-pt applications

QCD analyses on non-upgraded SVT datasets QCD analyses on non-upgraded SVT datasets have started, entering a new era of high-have started, entering a new era of high-statistics high-pt b physicsstatistics high-pt b physics