B masses, lifetimes and mixing at the Tevatron

Moriond QCD: March 2005 F. Bedeschi, INFN-Pisa

1/23

B masses, lifetimes and mixing at the Tevatron

OUTLINE

XXXXth Rencontres de Moriond

La Thuile, March 12-19 2005

Franco Bedeschi

INFN-Pisa

Tevatron and DetectorsData setsMassesLifetimesMixing


2/23

Data sets

CDF/D0 use data collected in the period 2002-2004~ 600 pb-1 recordedD0:

~ 220-450 pb-1 used for B physics

CDF: ~ 240-360 pb-1 used for B physics

Lost ~ 100 pb-1 due to Central Tracking Chamber ageing problem

Now completely resolved


3/23

Data samples

J/ samples: Millions! ~ 20% are from B’s Reconstruct exclusive B/BJ/ K/ modes

Semi-leptonic B D l X samples: ~ 100 K events with fully reconstructed D

D0 has larger muon acceptance

CDF lowers lepton trigger pt by requiring additional displaced track

Fully hadronic decays (CDF only) ~ 10 K events fully reconstructed B’s Requires trigger on secondary vertex (SVT)


4/23

B hadron lifetimes

B hadron decays dominated by b-quark decayEffect of spectator quarks can be

included with perturbative expansions in terms of 1/mb (HQE)

Expect small differences between lifetimes of different species

Non-perturbative ME from lattice, Wilson coeff. from perturbative QCD

NLO improves agreement

Ratios reduce theory uncertainties

C. Tarantino, hep-ph/0310241October 2003

ExperimentTheory

LO NLO


5/23

LifetimesHFAG 2004 averages as of summer 04 (hep-ex/0412073 Jan. 2005)

B0, B+ dominated by BaBar/Belle (latest not yet included in HFAG average)Best result from Belle: calibration result for Tevatron measurements

B0: 1.534±0.008±0.010, B+: 1.635±0.011±0.011, (B+)/(B0)=1.066±0.008±0.008

Bs, B: dominated by CDF/D0, LEP (B+)/(B0): No Tevatron Run II results included Bs: Includes Run II D0 J/ (220 pb-1), CDF J/ (240 pb-1)

See talk by S. Burdin for new s/s measurements

B: Includes Run II D0 J/ (250 pb-1), CDF J/(65 pb-1)b hadron species

average lifetime /(B0)

measurement/(B0)Theory 2004 (*) (NLO)

B0 1.534 ± 0.013 ps

B+ 1.653 ± 0.014 ps 1.081 ± 0.015 1.06±0.02Bs 1.469 ± 0.059 ps 0.958 ± 0.039 1.00±0.01B 1.232 ± 0.072 ps (0.803 ± 0.047) 0.86±0.05

(*) Gabbiani et al., hep-ph/0407004 Oct.2004


6/23

Lifetimes with BlDX modes

Highest statistics samples Difficult systematics:

Sample composition for Bu, BdCross talk from D**, D*

Backgrounds:CombinatorialPhysical: BD(*)D(*)

Prompt: c-cbar, b-bbar, D+fake

Recent result from CDF with low statistics lepton pt > 8 GeV sample

(B+) = 1.653±0.029±0.032 ps, (B0) = 1.473±0.036±0.054 ps (B+)/(B0) = 1.123±0.040±0.040

Very high statistics secondary vertex triggered sample still under study

13,300Signal events

260 pb-1


7/23

Lifetime ratio with BlDX modes

D0: new method to determine (B+)/(B0): Fit the ratio of the lifetime distributions

Many systematics are reduced in the ratio

Best measurement of this ratio at Tevatron

(B+)/(B0) = 1.08±0.016±0.014

440 pb-1

~ 126,000 D0


8/23

Lifetimes with BslDsX modes

First high statistics Bs lifetime measurement from D0 Use Ds+ decay Difficult background systematics:

Combinatorial

Physical: BD(*)D(*)

Prompt: c-cbar, b-bbar, D+fake

Currently best measurement(Bs) = 1.420±0.043±0.057 ps

DsD+

RSWS

M()

400 pb-1

NDs = 5153

Sys

tem

atic

s S

umm

ary

(m

)


9/23

Lifetime with hadronic decays

CDF: First measurement with Secondary

Vertex Trigger biased samples Trigger/analysis ct-efficiency curves

from “realistic” MC

Check by emulating trigger cuts on B+ J/ K+

Use several final states B±: D0± [8380 ev.] (D0K) B0: D± [5280 ev.] D±K)

D± 3ev.] (D±K) Bs: Ds ± [465 ev.] (Ds)

Ds 3 [133 ev.] (Ds)Important for ms measurement

B- ct-efficiency

B- D0-


10/23

Lifetimes with hadronic decays More statistical power than

J/ modes Slightly larger systematics

Efficiency curve backgrounds

B+

B+

Bs

Bs

Systematics (m)

(B+) = 1.661±0.027±0.013 ps (B0) = 1.511±0.023±0.013 ps(Bs) = 1.598±0.097±0.017 ps


11/23

Lifetimes: new results summary

Many new results not included in HFAG 2004 averages To come:

CDF high statistics semi-leptonic resultsRatios in several modesUpdates on B

Lum. CDF modes D0 modesCDF hadronic

CDF semi-leptonic (Hi pt)

D0 semi-

leptonic () HFAG pb-1 240 220 (250) 360 260 400 2004

B0 1.539±0.051±0.008 1.473±0.051±0.0231.511±0.023±0.013

1.473±0.036±0.054 1.534 ± 0.013

B+ 1.662±0.033±0.0081.661±0.027±0.013

1.653±0.029±0.032 1.653 ± 0.014

B+/B0 1.08±0.042 1.123±0.040±0.040 1.08±0.016±0.014

1.081 ± 0.015

Bs 1.369±0.100±0.009 1.444±0.094±0.0201.598±0.097±0.017 1.420±0.043±0.057 1.469 ± 0.059

Bs/B0 0.890±0.072 0.980±0.073±0.003 0.958 ± 0.039

B (1.22±0.20±0.04) 1.232 ± 0.072 Red = Very recent! Just approved

Included inHFAG averages


12/23

B mixingNeutral B’s mix:

SM interpretation with box diagrams

Frequency md,s |Vtd,s|2

Constraints to CKM weak due to theory uncertainties

Theory accuracy ~5% in ratio md/ms

Bd mixing measured and established clearly

LEP, CDF-1, CDF-2, D0-2, BaBar, Belle

Bs mixing not observedLimits set by LEP, SLD, CDF-1


13/23

B mixing Basic ingredients for the measurement:

High statistics samples of neutral B’s in flavor specific decaysCDF: J/K, D, lDXD0: J/K, lDX

Proper decay length reconstructionFully reconstructed modes provide better accuracy

Tagging of flavor at production (flavor tagging)Key problem at the Tevatron!Equivalent statistical power: N D2

= tagger efficiencyD = tagger dilution = 2*-1 ( = probability of correct tag)

Measure: A(t) = (Nnm-Nm)/ N = D cos(m t) Nnm (Nm): number of B’s with same (different) flavor at production and

decay Mixing measurement calibrates dilution

Impossible for Bs until oscillation observed


14/23

Bd Mixing

HFAG Summary Based on result presented in summer 2004

World Average dominated by BaBar/Belle


15/23

Flavor tagging

Opposite side techniques (OST): CDF: total D2 ~ 1.1 – 1.4 %

Soft Muon Tag

Soft Electron Tag

Jet Charge Tag

D0: D2 ~ 1.1% Enhanced muon tag D2 ~ 1.1%

Add-in correlations with associated jet in likelihood

Same side techniques (SST): Sign of nearby track is correlated to

b type (SST)Tagging power depends on B type

PID helps for Bs

D2 ~ 1% for CDF&D0 in Bd

,K+

Opposite side B

Signal side


16/23

Bd mixing

2 recent results from CDF using 355 pb-1 and OSTSemi-leptonic sample: 124k lD0 (24k lD*+), 53k lD+

md = 0.497 ± 0.028(stat.) ± 0.015(syst.) ps-1

Hadronic sample: 5.3k K+, 2.2k K+, 6.2k D0, 5.6k D+md = 0.503 ± 0.063(stat.) ± 0.015(syst.) ps-1

lD sampleJQT (Vertex)

Fit projection

Average all taggers


17/23

Bd Mixing

These results obtained using many features important for Bs mixing Unbinned fit Parametrized dilutions Calibrate dilutions

Test amplitude scan on fully reconstructed Bd

Fit D*A*cos(m t) at fixed m Expect A=1 for m ~ md

Limit (95% CL): m such that A+1.645A = 1

Sensitivity: m such that 1.645A =1

CDF had CDF semi D0 semi

Tagger % % %

OST 0.46 0.50 1.07

OST e 0.18 0.28

OST jet 0.49 0.61

Total OST 1.13±0.18 1.38±0.10 1.07

H. G. Moser, A. Roussarie, NIM A384 (1997)

Sensitivity

Limit


18/23

Bs mixing

Tevatron experiments do not have yet sensitivity for observation of SM prediction

New results:CDF:

Limit with combined fully reconstructed and semi-leptonic modes (this talk)

D0: Limit with semi-leptonic modes (S. Burdin talk)

SM Fit (2004): ms = 18.3 ± 1.6 ps-1


19/23

CDF: Bs mixing (signals)

Hadronic analysis: BsDs ~ 900 events

Cross-check with hadronic lifetime analysis (independent group)

Semi-leptonic analysis: BsDsl ~ 7.5k events

Cross-check with parallel independent analysis

Channel Yield S/B

BsDsDs 526±33 1.80

BsDsDs 254±21 1.69

BsDsDs 116±18 1.01

BsDslDs 4355±94 3.12

BsDslDs 1750±83 0.42

BsDslDs 1573±88 0.32

hadronic peakssemi peaks

Rightsign

Wrongsign


20/23

CDF: Bs mixing (cross-checks)

Mass and lifetime projectionsMass and lifetime consistent

with World Avg. values/D0

BsDs (Ds)

Details (K-f) (ct-eff) (ct-SF) (had, lD)

Ds

Bs = 1.518±0.090


21/23

CDF: Bs Mixing (scans-1)

Amplitude scans all statistics dominated

Sem

i-le

pto

nic

Had

ron

ic


22/23

CDF: Bs mixing (scans-2)

Combined scan results:7.9 ps-1 95% CL limitSensitivity: 8.4 ps-1

Effect on World Average:Limit: 14.5 14.5 ps-1

Sensitivity: 18.2 18.6 ps-1

Old projections

CDF Run 1 limit


23/23

Conclusions

Many new results from the TevatronMajor new results in Bs sectorMore Bs results from D0 (talk by S. Burdin)Lifetime updated and more to comeFirst CDF/D0 Bs mixing limits

Lower than expectations

Additional improvements could reduce the statistical error on the amplitude by up to a factor two with same data set

It is a very difficult analysis, but now we are in business


24/23

Backup


25/23

Tevatron

Tevatron is delivering good luminosity consistent with 2002 predictions ~ 750 pb-1 delivered per experiment since start of Run II Peak luminosity in excess of 1032 Best 1.1x1032

Injections around 1032 are now rather common occurrenceGood Recycler performance


26/23

Detectors CDF:

Excellent mass resolution Particle ID: dE/dx, TOF Tracking triggers (Hadronic B’s):

L1: Tracks

L2: Secondary vertex

D0: Excellent muon and tracking

coverageTracking up to ||<3

Muons up to ||<2


27/23

Masses

CDF:Old 04 results:

D+ Ds mass difference

D** states D1, D2

B meson masses

New winter 05 results:Hadronic Bc

B** fits (PR plot)

D0:Old 04 results:

Narrow B** resonances

B--> narrow D** sates (D1, D2)

Bc meson in semileptonic decays

New winter 05 resultsD**s states


28/23

B hadron masses

B mass determination Use clean J/K modes Accurate tuning of

momentum scale with large J/ sample

D0D0

CDF CDF


29/23

Masses

Run II results ~ or better of current world averagesCDF has best results due to better tracking resolutionClose to being systematics dominated

B hadron species

Mass (MeV/c2)

CDF Run II (2004)

Mass (MeV/c2)

PDG 2004 average

PDG Reference

B+ 5279.1 ± 0.41 ± 0.36 5279.1 ± 0.5 CLEO2 (00), CDF(96)

B0 5279.6 ± 0.53 ± 0.33 5279.3 ± 0.7 CLEO2 (00), CDF(96)

Bs 5366.0 ± 0.73 ± 0.33 5369.6 ± 2.4 CDF(96), LEP

B 5619.7 ± 1.2 ± 1.2 5624 ± 9 CDF(97), LEP

Bc See next talk by

M.Corcoran 6400 ± 390 ± 130

6320 ± 60

CDF(98) - Semileptonic

OPAL(98) - J/


30/23

X (3872)

CDF (11.6 and D0 (5.2) confirm X (3872) observations from the B factories

CDF measures large prompt fraction fB(X) = 16.1±4.9±2.0%

fB((2S)) = 28.3±1.0±0.7%230 pb-1


31/23

Masses

Many results not covered in this talk:Charmless two body decays l ni

Bc in fully and partially reconstructed modes (next talk) Measurements of D** and B** narrow resonances l ni

Pentaquark searches l ni

Charmed baryons l ni


32/23

B hh

Several new results based on this sample presented at ICHEP last summerBranching fractions Integrated CP asymmetries

back


33/23

Bhh

Branching ratios and CP asymmetry

Rare two body decay modes

back


34/23

Bh

CDF: B+ K+

ACP = -0.07 ± 0.17 ± 0.05

(BaBar: 0.054 ± 0.056 ± 0.012) BR(B+ K+) = (7.2 ± 1.3 ± 0.7)x10-6

(HFAG: (9.0 ± 0.7)x10-6)

CDF: Bs BR(Bs) = (1.4 ± 0.6 ± 0.2 ±

0.5(norm))x10-5

(QCD fact. 3.68x10-5)

(NF fact. 1.79x10-5)

First observation!

back


35/23

D** mesons

CDF: Mass and width

D0: B.R. Belle hep-ex/0307021

MeV25

300MeV4

back


36/23

B** mesons

D0:First high statistics

observation

CDF:Preliminary results

consistent with D0

back


37/23

Pentaquark searches

Pentaquark signal searched by CDF

No evidence observed so far Set limits on production cross-section

back


38/23

Charm baryons

Charm baryons observed for first time at p p-bar collider by CDF

back


39/23

Lifetimes

CDF:Old 04 results:

Bs/Bd polarization and lifetime differenceExclusive psiK lifetimes & Bu/Bd lifetime ratio

New winter 05 results:Lifetimes from semileptonic 8 GeV dataLifetimes from hadronic modes

D0:Old 04 results:

Bs lifetime from psi phi mode (Bs/B0)

Bd/Bu lifetime ratio

New winter 05 results:DGs/Gs results and polarization studies

Bs lifetime using DslvX

back


40/23

Lifetimes with J/ K modes Cleanest channels, but statistics limited:

Best Tevatron results from CDF (240 pb-1)B+ K+, B0 K*, K0

S, Bs Main background from prompt + tracks No kinematic uncertainty Systematics at level of B factories

(B+) = 1.662±0.033±0.008, (B0) = 1.539±0.051±0.008(Bs) = 1.369±0.100±0.009

NBs = 256


41/23

Mixing

CDF: Old 04 results:

B0 oscillations with SST in fully reconstructed decaysB0 oscillations with OST in semileptonic decaysB0 oscillation with SST in semileptonic decays

New winter 05 results:B0 mixing with OST in hadronic decaysB0 mixing with OST in semileptonic decaysBs mixing with OST in hadronic decaysBs mixing with OST in semileptonic decays

D0:Old 04 results:

B0 oscillation with OS mu tag

B0 oscillation with SS tag

B0 oscillation with OS mu tag, Jet Charge and SST

New winter 05 results:Dms limit from semileptonic decays


42/23

CDF: Bs signals back

3

K*K Had

ron

ic s

amp

les

Wid

e ra

nge

Fit

pro

ject

ion


43/23

CDF: Bs signalssemi-leptonic samples

back

K*K 3


44/23

CDF: Bs lDs k-factors

K-factor = pt(lD)/pt(B)Binned by M(lD)

Ds Ds

Ds

back


45/23

CDF: Bs ct-efficiencies

Semi-leptonic sampleAll ct efficiencies obtained with realistic MC

Cross check: lifetimes consistent with D0/WA

back

Ds Ds Ds


46/23

CDF: Bs ct-efficiencies

Hadronic sampleAll ct efficiencies obtained with realistic MC

Cross check: lifetimes consistent with D0/WA

back

Ds Ds Ds


47/23CDF: Bs lifetime checkssemi-leptonic sample

Raw lifetimes from mixing fit – not good for averagingAverage: B = 1.477±0.032 ps no systematics evaluated

D0: (Bs) = 1.420±0.043±0.057 ps, WA: (Bs) = 1.469 ± 0.059 ps

back

Ds Ds Ds

Bs = 1.521±0.040 Bs = 1.381±0.067 Bs = 1.410±0.086TotalSignalCombin.Ph/Pr. Bck

TotalSignalCombin.Ph/Pr. Bck

TotalSignalCombin.Ph/Pr. Bck


48/23CDF: Bs lifetime checkshadronic sample

Raw lifetimes from mixing fit – not good for averagingAverage: B = 1.515±0.070 ps no systematics evaluated

D0: (Bs) = 1.420±0.043±0.057 ps, WA: (Bs) = 1.469 ± 0.059 ps

backD

s

Ds

B = 1.550±0.131 B = 1.377±0.186


49/23

CDF: Bs (ct) scale factors

(ct) scale factor distributions in semi-leptonic sampleCalculation from large data control sampleParameterization in terms of many variables

back

Ds Ds Ds


50/23

CDF: Bs (ct) scale factors

(ct) scale factor distributions in the hadronic sampleCalculation from large data control sampleParameterization in terms of many variables

back

Ds Ds Ds


51/23

Old Sensitivity Plots

Recall ICHEP August 2004 predictions (statistical only!)

ms ~ 15 ps-1ms ~ 9 ps-1

ms~14 ps-1

ms~23 ps-1

scanconclusions


52/23

Future Mixing Improvements

Include Same Side (Kaon) Tagging Expect twice tagging power than OST

combined

Improve accuracy of primary vertex Add more channels:

BsDs3 BsDs*, BsDs+

Partial reconstruction can treat as semi-leptonic case

back

-1

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B masses, lifetimes and mixing at the Tevatron