universita' "la sapienza", 11/6/2004 sandro de cecco - infn roma 11 sandro de cecco...

Universita' "La Sapienza", 11/6/2004 Sandro De Cecco - INFN Roma 1 1

Sandro De Cecco

INFN Roma 1

Universita’ di Roma “La Sapienza”, 11 giugno 2004

B-physics at CDFfirst results and perspectives


In this talk…

•This talk won’t cover all B-physics studies going on at CDF.

•I will stress on B physics potentials of CDF which are complementaryto the B-factories outputs.

•In particular I will concentrate on some information on CPV and HQthat can be extracted from the study of Bs meson only accessible at the Tevatron collider.

•In this perspective, a selection of relevant new results will be described.

•Future projections for Bs topics will be highlighted, relying on data andcurrent performances for extrapolations.


Outline

• Highlights on Bs physics

• CDF detector and B-triggers

• Selection of recent results in Leptonic & hadronic triggers data samples.

• Projections for Bs mixing measurement & first studies.

• CDF potential in relevant Bs decay channels, expected yields before next generation B-experiments.


CPV, the CKM picture

CPV at Tevatron in the b-sector:unique opportunity to study Bs physics.

DS- K+

CDF

CDF ?

BS K-K+ K

Babar/Belle/CDF

Babar/Belle/CLEO

Babar/Belle + theory

CDF/DØ + theory

Babar/Belle/CDF/DØ

Bd Ks0 Babar/Belle/CDF?/DØ?

BS


Explore one side of the CKM triangle

Key experimental issues:

B0s flavor ID at decay

B0s flavor ID at production (fl.tagging)

High Yield with good S/B. (trigger & reco.)

High resolution on proper decay time (Vertexing)

B0s - B0

s mixing

ms > 14.4/ps @ (95%CL)

World average limit

6

Bs Lifetime Difference: s

Bs system mass eigenstates BH and BL have ms = MH –ML and = L-H

With BL=pBs + qBs (CP-even); and BH = pBs – q Bs (CP-odd)

s/Ms in SM does not depend on CKM parameters s determines Ms up to QCD uncertainties (~20%)

– Large Ms (hard to measure) Large s (easy) complementarity

• Several methods available at Tevatron RunII:

•Bs J/ (Vector-Vector):

Angular analysis to separate

CP even/odd components

•Bs Ds/ DsDs:Fit 2 exponential to known mixture of states (ex. BsDs, BsDsl) Compare with CP eigenstate (ex. BsDsDs)

•Bs K+K-No angular analysis needed. ( direct CPV ? )

Compare to K mixed mode (but suppressed!) ~ 10,000 events in 6.5 fb-1

Hadronic modes (being evaluated):


CP asymmetry in B0s J/ dominated by b(cc)s probes the

weak phase of Vts (angle s = 2s):Also plan to look at BsJ/(’)

Expected to be small:sin(2s ) O(2) 0.03

Complicated analysis: requires ms and angular analysis to disentangle CP even/odd final states

CDF reach : (sin(2 s )) 0.1 with 2fb–1 (0.06 with 8fb–1)

If asymmetry observed with 2fb–1 signal for NEW Physics

CP violation in B0s

*cbcs

*tbts

s VV

VVargβ


Current experimental average of CP-asymmetry in B0d Ks is:

S(Ks) = - 0.15 ± 0.33 (hep-ex/0312024)

This is 2.7 from sin2 = 0.736 ± 0.049which is the SM prediction for this asymmetry to the percent level.

Several analysys of this result, in the frame of NP (SUSY), allow it to be negative

If this is true:

In the Bs sector this would imply High ms ( > 70 ps-1) (hep-ph/0404001) (april fool?)

ACP(B0s J/ ) i.e sin(2s) in the tagged sample will be: hopeless for CDF/D0 and very difficult even for LHCB – BTEV

Nonetheless untagged time-evolution (J/ ; t) will give information

on CP violation in the Bs from the sign of cos(2s) (in SM ~ 1)

through the dependence from ss if this is sizeable O(10%) and measurable

CPV in B0s J/ (2)

Recent Inputfrom B-factories


The Tevatron pp colliderSuperconducting proton-synchrotron: 36p36p bunches, crossing each 396 ns

at √s = 1.96 TeV

Luminosity……………………………..: record peak L = 7.2 1031 cm-2 s-1

# interactions / bunch-crossing……...: < N >poisson = 1.5 (at 5 x 1031 cm-2s-1)

Luminous region size………………...: 30 cm (beam axis) x 30 m (transverse)

Improved > 2x during last year


Tevatron plans• RECYCLER had a first successful test• Plans beyond FY 05 depends on

Recycler ring and electron cooling performances

• Will see after aug./nov.04 shutdown

Year Base plan luminosity/yr (fb-1)

Design plan

Luminosity/yr (fb-1)

FY02 0.08 0.08

FY03 0.20 0.22

FY04 0.31 0.38

FY05 0.39 0.67

FY06 0.50 0.89

FY07 0.63 1.53

FY08 1.14 2.37

FY09 1.16 2.42

Total 4.41 8.56

0

1

2

3

4

5

6

7

8

9

0 1 2 3 4 5 6 7 8 9 10

End FY

fb-1

Base plan

Design plan


Tevatron FY04 performance

• Tevatron is working very well this year (Design plan):

• Record Initial luminosity = 7.2 X 1031 sec-1 cm-2

• Weekly Integrated luminosity ~ 10 pb-1/w • ~350 pb-1 on tape, 100-200 pb-1 used for analysis so far

0

50

100

150

200

250

300

0 30 60 90 120 150 180 210 240 270 300 330 360

Days Since October 1

Inte

grat

ed L

umin

osity

(pb

-1)

FY04

FY03

FY02

FY04 Design

FY04 Base

1st May 2004

1st Jan. 2004

L (

pb

-1)

2003

2002

FY04 D

esig

n

FY04 Base


The CDF II detector

TrackingSystem

Completely new:


CDF II tracking system

LAYER 00: 1 layer of radiation-hard silicon at very small radius (1.5 cm) (achievable: 45 fs proper time resolution in Bs Ds )

COTCOT: large radius (1.4 m) Drift chamber

• 96 layers, ~100ns drift time • Precise PT above 400 MeV/c

• Precise 3D tracking in ||<1

(1/PT) ~ 0.1%GeV –1; (hit)~150m

• dE/dx info provides >1 sigma K/ separation above 2 GeV

SVX-II + ISL: 6 (7) layers of double-side silicon (3cm < R < 30cm)• Standalone 3D tracking up to ||= 2• Very good I.P. resolution: ~30m (~20 m with Layer00)

TOF: 100ps resolution, 2 sigma K/ separation for tracks below 1.6 GeV/c (significant improvement of Bs flavor tag effectiveness) - charge)

TIME OF FLIGHT

CDF Roma


B Physics at pp collider

• Huge cross-section: 50-100 b

• All B species produced:

Bu,Bd,Bs,Bc,b, b…

with production fractions:

fu : fd : fs : f ≈ 4 : 4 : 1 : 1

BUT: (bb) << (pp) (~65 mb) B events have to be selected with specific triggersTrigger requirements: large bandwidth, background suppression, small dead-time

Flavor Creation (annihilation)

q b

q b

Flavor Creation (gluon fusion)

bg

g b

Flavor Excitationq q

b

g

b

Gluon Splitting

bg

g g

b

BB production mechanics in hadron collider:


B physics at CDF

Typical > 1 (B-factory ~0.56) B hadrons are hidden in a x103 larger

background (inelastic(pp) 50 mb) And events are much more

“complicated” than at (4S)

Crucial detector components:- Tracking system Excellent pt resolution/Vertexing- Trigger Large bandwidth Strong background reduction- Particle identification

CDFCLEOCLEO


B physics triggers at CDF II

Displaced track + lepton (e, )I.P.(trk) > 120m

Pt(lepton) > 4 GeV

Semileptonic modes

2-Displaced tracks

PT(trk) > 2 GeV

pT > 5.5 GeV

I.P.(trk) > 120(100) m

fully hadronic modes

Di-Muon (J/)

Pt() > 1.5 GeV

J/ modes down to low Pt(J/)~0 (Run II)

- CP violation

- Masses, lifetimes

- Quarkonia, rare decays

- High statistics lifetimes

- Sample for tagging studies- BS mixing

- Charmless decays

With the New Silicon Vertex Trigger

primary vertexsecondary vertex

Impact Parameter ( ~100m)

~ 1 mm

b decaysConventional at colliders (Run I)

+


SiliconVertexTracker: the hadronic B trigger

≈ 47 um ≈ 35 um + 30 um

SVT resolution Beam spot size

Online Impact parameterAvailable at Level 2 trigger (20µs latency)

convolution of transverse size of the beam spot with the impact parameter resolution of the SVT:

Impact parameter distribution

Compare to offline ~ 46 m

d

beam spot

COT track ( 2 parameters) 5 SVX coordinates

Impact Parameter (transverse projection)

- Responsabilty CDF Roma


@ high Lumi.: Dynamic PreScale of had. trigger


BB(s)(s) physics from Di-Muon triggers physics from Di-Muon triggers


Exclusive BsJ/ Lifetime

B hadron CDF measurement PDG value

B+ 1.662 +/- 0.033 +/- 0.008 1.674 +/- 0.018

B0 1.539 +/- 0.051 +/- 0.008 1.542 +/- 0.016

(138pb-1) b 1.25 +/- 0.26 +/- 0.10 1.229 +/- 0.080

Bs 1.369 +/- 0.100 +0.008(-0.010) 1.461 +/- 0.057

CDF RunII preliminary results (in ps)


B Lifetime summary

•Accurate measurements from Tevatron, still statistics-dominated

•Theory errors are still smaller than experimentHQET:(B+)/(B0) = 1.067 ± 0.027(Bs)/(B0) = 0.998 ± 0.015

(b)/(B0) = 0.90 ± 0.05

•More B hadrons coming:

Bc , b


Polarization amplitudes of BsJ/ and BdJ/K*

Both channels are Vector–Vector final states:

The Helicity amplitudes of the 2 Vectors are correlated

•Measure the angular distributions of decay products in transversity basis

•The convenience of transversity basis ( A0 ; A|| ; A┴) instead of Helicity (H-;H0;H+) is to separate CP even ( A0 ; A|| ) from CP-odd ( A┴ ) eigenstates.

•Measurement for Bd is to be compared to the B-factories resultsand gives confidence on Bs:

Analysis of BsJ/ polarization is the first step towards/s and CPV.


BVV in transversity basis

In the J/ rest frame the transversity plane is defined by K* (K)or (KK) decay products and transversity axis z is orthogonal to it.

J/ *B

z

transversity plane


Transversity amplitudes

Angular distribution: Amplitude parametrization:

from measurable distributions of :

cosK ; cosT and K


BsJ/ BdJ/K*

NB=176±16 NB=993±58

Results:

•Based on 180 pb-1 of integrated Luminosity.•Data collected with Di-Muon (J/) trigger. •About 1000 Bd and 180 Bs candidates pass selection cuts.•BsJ/ (K+K-) and BdJ/K* (K0*K+-)

Polarization amplitudes measured with an un-binned Likelihood fit.


BdJ/K* angular distributions

cosT T

cosK

Main systematic:

•K- misidentification (no PID used)

•Detector acceptance sculpting onangular distributions


BsJ/angular distributions

cosT

cosK

T

Main systematic:

•Assumption (on limited statistics)of equal number of Bs and Bs

reduced form of angular distributions.

•Detector acceptance sculpting onangular distributions.


Polarization results summary:

BsJ/

BdJ/K*

•Results are consistent with previous measurements

•BsJ/ mostly CP-even state: (A02+A||2) ~ 80% ↔ mostly BsL

• This is helpful for CPV analysis

• Lifetime measurement dominated by sL

if sizeable CDF starts to be sensible to this effect.


Rare B decaysRare B decays


Search for rare B decays: Bs(d)+-

• SM prediction: BR(Bs+- ) = (3.8 ± 1.0) 10-9

• Several extensions to the SM predict an enhancement of this branching ratio by 1 to 3 orders of magnitude• If there is not excess we can already constrain several SUSY models!

Discriminating variables

“Blind” analysis: cuts were optimizedbefore looking at the signal mass region


Rare B decays: Bs(d)+-

• No excess has been found• Limits on the Branching fractions have been set

Bs+- Bd+-

Background 1.05 +/- 0.30 1.07 +/- 0.31

Data 1 1

BR limit @ 95% C.L. 7.5 X 10-7 1.9 X 10-7

BR limit @ 90% C.L. 5.8 X 10-7 1.5 X 10-7

Best world result

Slighly better results than Belle and BaBar @ 90% CL

1.6 X 10-7 2.0 X 10-7

Submitted to PRL

Final B mass distribution


Bs implications for SUSY

R. Arnowitt et al.,PLB 538 (2002) 121,new plot by B.DuttaR-parity violatingR. Dermisek et al.,

hep-ph/0304101

7.510-7

SO(10)

CDF BR limitsvs. luminosity (Expected/Obs.)

BR = ~10-7 @ 500pb-1


BB(s)(s) physics from Hadronic triggers physics from Hadronic triggers


Charmless B decaysCharmless B decays


BB(s)(s) hh’ hh’BB(s)(s) Pseudoscalar Vector Pseudoscalar Vector

BB(s)(s) Vector Vector Vector Vector


Bhh decays at the Tevatron

“Tree” “Penguin”

direct CP CP from mixing alone

Bd/s

Bd/s

Bd, BdK, BsK, BsKK

Bd ACP(t) =ACP cos(mdt)+ACP sin(mdt)

Bd K ACP = (N+ - N-)/(N+ + N-)

Bs K ACP = (N+ - N-)/(N+ + N-) Bs KK ACP(t) =ACP cos(mst)+ACP sin(mst)

dir mix

mixdir

dir

dir

/K

/K

/K

/K

Bs channelsnever observed


Reconstruction of Charmless 2-body

•min(|d01|,|d02|) 150 m

•Lxy (B0) 300 m

•|dB0| 80 m , d01 · d02 < 0•I(B0) > 0.5 (ISOLATION)For further back.reduction

•min(|d01|,|d02|) 150 m

•Lxy (B0) 300 m

•|dB0| 80 m , d01 · d02 < 0•I(B0) > 0.5 (ISOLATION)For further back.reduction

BdBdKBsKKBsK

Montecarlo

•Specific trigger path optimized for Bhh

NB = 870

NB = 1770

Need to separate contributions !


K

Separation of B0h+h- contributions

Use M vs (1-p1/p2)q1

B0d B0

d K- B0d K+

B0s K+ B0

s K-B0s KK

Use dE/dx calibrated on D*

(K/ separation 1.4 pT>2GeV)

… Fit the fractions

CDF Roma


B h+h'- results with 65 pb-1

•BR(Bd ) / BR(Bd K) = 0.26 ± 0.11(stat) ± 0.06(syst)

Consistent with B-factories results (0.250.06)

•Direct ACP(BdK) = 0.02 ± 0.15(stat) ± 0.02(syst)

•fs·BR(BsKK) / fd·BR(BdK) = 0.74±0.20(stat)±0.22(syst)

First evidence of Bs K+K- (CDF’s largest fully reconstructed Bs sample!)

Update on 185pb-1 coming out soon x4 statistics and smaller syst (mainly dEdx)

53%

14%

32%1%

BBd d Bd K

Bs K Bs KK


B h+h'- future measurements •BsK BR & ACP measurement

•Limits on Bs, BdKK

•Lifetime in BsKK : s

•ACP in Bd,BsKK

Bs+Bd BRs’ alone provide, via U-

spin simmetry, information on (R. Fleischer hep-ph/0306270) and checks of CKM model (Matias&London, hep-ph/0404009)

hep-ph/0404009BsKK

Bd

Longer time-scale: time dependent ACP in BsKK

measure xs independently of penguin pollution (Fleischer and Matias: PRD669 (2002) 054009)

Expected yields


time-dep study: Angle from B0h+h-

B0 + has two (comparable) decay amplitudes:

Tree Penguin

b

d

W+u

d

u

+

B0 d

ACP(t) = ACP dir cos(md t) + ACP

mix sin(md t)

ACPdir, ACP

mix functions of , , d, (d ei P / T decay amplitude)

direct CP CP from mixing alone

R. Fleischer (PLB 459 (1999) 306): Assume U-spin symmetry (d s)

Similar relation holds for Bs K+K (md replaced by ms)The 4 asymmetries can be expressed as function of , and P/T amplitude ratio

Parameters can be extracted from fit of meas. of ACP(t) for Bd and BsKK

d

b W+

u

+

B0 u,c,t

d

d

u

g


BPV & BVV charmless decays• QCD Factorization provides a predictive framework for calculating PV and VV two

body charm-less decays rate (less good at CP violation parameters…)• Recently many authors have combined all the available data to fit for the CKM angle :

– D.Du hep-ph/0311135– N. deGroot et. Al hep-ph/0305263– Beneke and Neubert Nucl Phys B651, 225

– These fits are as useful in constraining as all other experimental inputs!

• Theorist are now opening the Bs field:– D.Du et al hep-ph/0211154 (PP, PV)– Y.Yang et al hep-ph/0309136 (VV)

• This is a call for CDF and the hadronic trigger :– Mostly these are rate measurement!– Provide several crucial tests of QCDF– Improve overall confidence

• In many respects the same physics motivating Bhh study can be done replacing K*+ with K+ , or Ks with K*0, and 0 with . Examples are:

– Bs K*+ K*- , Bs K*+K- , Bs K*-K+ , BsK*+, Bs K*0 K*0 , Bs K*0Ks

CDF can recover in part the lack of efficient 0 detection or Ks trigger efficiency!


• Rich dynamic revealed by Vector-Vector decays• Angular correlations additional observables (CKM studies)• Many Bd,u modes are being measured at B-factories

• BVV charmless :– Study polarization and CP violation

• Hints for some NP(?) contribution in bs penguin dominated decays:– if NP effects in Ks is true, also visible in:

• Bd,uK* ACP and/or angular distributions (hep-ph/0309282)

• Bstime dependent CP asymmetry hep-ph/0208091– First results (BaBar-Belle) on polarization unexpectedly small:

• fL(K* ) << fL()

How canCDF contribute ?

BPV & BVV charmless decays


• Atwood and Soni (hep-ex/010683) proposed a method based on the study of angular correlation in pure penguin decays (third column) compared to a tree-penguin decays which can give (bs transitions) or (bd transitions)

• Easy analysis do not need tagging!• A lot of useful modes are accessible to CDF with SVT trigger, probably CDF can be

successful with high luminosity• Bs modes can give additional constraint to the Bd,u modes available at B-factories

Atwood Soni grid

Many of the interesting decay color suppressed !


Bs VV charmless decays

• Rich harvest of interesting and unseen decays from Bs (hep-ph/0309136)

• Only the 0-less shown in the table here

• Measure them all!• Interesting ACP possible

for self tagging modes:– K*

Decay BR(10-6)

K* 1.95

K*+K*- 2.10

1.67

K*0K*0 3.72

K* 0.2

36.8Pure

penguin

b

sbd

QCDF predictions (hep-ph/0309136)


BB± ± → → KK±±


BR and ACP for B±→ K±

► BR and direct CP asymmetry measurement ► Luminosity used:± 10 pb► Performed a multidimensional un-binned fit to mB, m, helicity and dE/dx

PID information.

► Yield result from fit: N = 47±8

► S/N = 1, main resonant background contribution from B± → f0K±

total PDFsignalcomb. BGphys. BGB±→ f0K±

B±→ K*0±

B±→ K±K-K+

B±→ K±-+

Legend:

CDF Roma


BR for B±→ K±

BR is measured relative to normalizationmode B+J/K+ :

Using the PDG value:

Which is already comparable precision with B-factories

CDF Roma


ACP for B±→ K±

From multidimensional fit, direct CP asymmetry is also extracted:

•BaBar [hep-ex/0309025], •Belle [hep-ex/0307014],•CLEO [Phys. Rev. Lett 86, 3718 (2001)]. •The Heavy Flavor Averaging Group mean has been superimposed.

CDF Roma


BBs s


Observation and BR of Bs •This is an unseen hadronic mode search in the hadronic trigger.

•Performed a blind analysis: optimize cuts a priori open the box

•Put a limit or measure the BR relative to BsJ/ (normalization mode)

•Use BdJ/ K* as control sample for B variables and polarizations.

•First analysis using also the “Low PT” version of hadronic trigger.

•Main systematics are:

• J//ee deconvolution in normalization mode

•Polarization amplitudes and s/s unknowns for Bs

•Poorly measured BR(BsJ/) = (9.3 ± 3.3)10-4 (CDF Run1)

•Peaking reflections in blinded region and normalization mode.

CDF Roma


Optimization procedure: sidebands choice

MMKKKK

MKKMKK

MMKKKK

MMBsBs

BsJ/ Optimize for S/√(S+B) with S from MC and B from sidebands

Bs:Optimize S/1.5+√B (BR unknown!) with S from MC and B from sidebands

CDF Roma


BsJ/ (the normalization mode):

(LowPt andNOT Scenario A)

Excellent S/B !

N(BsJ/) ≈ 100 after optimized cuts

CDF Roma


Results for Bs Scenario A Low PT

Very clean mode!

CDF Roma


Observation and BR of BsProbability for the expected BG to fluctuate to the observed number of events in the hypothesis of null signal:

is the expected BG

N number of events in signal region

P = 1.28·10-6 → N

We measure then the BR, with:

…Future: measure polarization and relative BR to BdK*

Main systematicfrom normalizationmode BR knowledge

(QCDF Prediction for branching ratio: 3.7x10-5 hep-ph/0309136)

CDF Roma


BB(s)(s) charmed hadronic modes charmed hadronic modes


B(s) D(s) (in 119 pb-1)

Bs Ds B+ D0 Bd D+

CDF Roma


BR(Bs Ds

•Fully reconstructed hadronic Bs decayGolden mode for Bs mixing measurement

BR relative to Bd mode (x fs/fd) was measured:(with 119 pb-1 of hadronic trigger data)

•Using the world average value for:

Future:

new measure productions fraction fs/fd with high statisticsand several Bs BR’s


BB(s)(s) mixing @ CDF mixing @ CDF


B0s - B0

s mixing

Was Bs or Bs at the time of decay ?

Triggering and reconstructing flavor-specific final states:

high c resolution completely reco., lower yield Bs Ds (Ds , K*K, )

high yield & S/B, worse c res. Missing PT Bs Ds l n + X

Was it a Bs or Bs at production?

charge-flavor correlations and bb production:

Primary VertexSoft lepton

Jet chargeopposite Kaon

Bs

b-hadron

c

fragmentation Kaon

+

Ds-


Effective tagged sample statistics: = efficiency of taggers, D Dilution

D2 figure of merit )N is the Bs yield

Significance of B0s mixing measurement

110 - 150•l+X

67 (50 exp. with LØØ)•Hadr

[ fs ]

SIG(ms) ≈

vertexing and momentum resolution

Signal / Noise

Mixing asymmetry


Event by event Primary Vertex determination:

Typical (Lxy) ~ 40 m (with convolution of ~ 30 m beam spot spread)

() ~ 70 fs

If Primary vertex is determinedFor each event with <Ntrk> ~ 5

() ~ 50 fs

Improving proper time resolution

“Away side”

Reconstructed B

Opposite B R- view (transverse plane)

P.V.“Same side”

CDF Roma


B initial state flavour tagging @ CDF

Opposite SideOpposite Side

Same SideSame Side

Opposite Side K: due to bcs it is more likely that a B0

s meson will contain in final state a K+ than a K-.

search for K from secondary opposite vtx

SS Pion: B0d is likely to be accompanied

close in DR by a + from fragmentationSS Kaon: for B0s is likely to be accompanied close in DR by a K+

search for /K from Primary vertex

Soft Lepton (e,) due to blXThe charge of the l is correlatedto b-flavour Search lepton from sec. vtx.

Jet Charge: the sum of charges of the b-Jet tracksis correlated to the b-flavour Away Jet reconstruction


•Statistical uncertainty for tagging efficiency:–A typical tagging: =0.1,D=0.4,D2=1.6%

–1000 events: D2 =1.6+0.7% (44%)–100K events: D2=1.60+0.07% (4.4%)

•We can’t study/optimize the flavor tagging with ~O(1000) events of the reconstructed B signal

– B J/K: ~ 1000 events/100pb-1

– B D: ~ 500 events/100pb-1

•Solution: Use Semileptonic B decays in the lepton + track dataset

– ~200K semileptonic B signal events– High B purity– Lepton Charge = Decay flavor of B

Flav. Tag. control sample: lep+track trigger

No charm contamination

>40000 B l D0 X decays!

…First Bs(d) mixing limit might be done in Semileptonic B decays…


Soft muon tagging

After correcting for mixing and sequantial decayson trigger side the -D^2, expressed in percentand averaged over e+SVT and m+SVT data sample is:

D^2 = 0.660 +- 0.093 %


(Opposite b) Jet Charge tagging

Run II PRELIMINARY

Qjet = i Qi (Pi ∙Pjet) i (Pi ∙ Pjet)


Bd mixing with Same Side tagging

Based on correlation betweencharge of fragmentation and flavor of b in B meson

Run II PRELIMINARY


Opposite Side Kaon Tagging

Issues:•N(B0/B+K+)/ N(B0/B+K-)5 , not infinite, intrinsic Dilution.

•Only 20-40% chance for both B in the detector acceptance

•Tagging purity depends on TOF resolution.

•Tagging algorithm figure of merit D2 depends on TOF matching efficiency

Opposite side Kaon momentum spectra from B0, B+, Bs admixture MC

We can implement OSKT with the useof dE/dx for higher momentum tracks.

CDF Roma


B flavour tagging summary:

• Projection for CDF Bs mixing sensitivity are currently using:

D2= 4% (w/o TOF) 5% (with TOF)

D2(%) Run-I Run-II Projection w/o

TOF

Projection with TOF

Key improvements

SST-/K 1.5±0.4 1.0±0.5 2.0 2.0 - 4.2 Silicon dE/dx, TOF

SLT- 0.6±0.1 0.7±0.1 1.0 1.0 Extend

coverage

SLT-e 0.3±0.1 --- 0.7 0.7 Plug Cal/ISL

JetQ 1.0±0.3 0.42±0.03 3.0 3.0 COT/SVX

OSKT --- --- --- 2.4 TOF

TOTAL 3.4 2.1 6.7 11.3


Hadronic Yields for Bs mixing• Currently: ~ 1600 / fb-1 of clean hadronic modes


CDF Bs mixing prospect with 500pb-1 (had. Modes only)

• With current performance

– S=1600 event/fb-1

– S/B=2/1 D2 = 4% (SLT+SST+JetQ)

t = 0.067ps

• 2 measurement if ms=15ps-1

from 500pb-1 data

• Beat current limit from indirect

measurements ms>14.4 ps-1@

90% CL (HFAG 03)

• Reach Standard Model favored

region (at least!)

222

2

s tmS D SSignificance e

S B

TAG

WR

WR

WR

WR

PDNN

NNA

mtDtNtN

tNtNtA

21

cos)()(

)()()(

… this is not much…

- ms is the most complex of all B measurement - Need to combine many ingredients


• Expect Tevatron to deliver luminosity of– 2.11fb-1 (based line) and 3.78fb-1(design) by 2007

• With modest (sic!) improvement for CDF– Add Ds K*K, KsK and BsDs

-+ - +

(to update) S=16002000 event/fb-1

– With improved TOF to enhance both SST and OKT

D2 = 4% 5%

– With L00 silicon and Event-by-Event beamline

ct = 0.067 0.05ps

CDF Bs mixing prospect with 2fb-1


Bs mixing future projections

• 5 measurement if ms=18ps-1 with 1.7fb-1 data

• 5 measurement if ms=24ps-1 with 3.2fb-1 data

This is not dramatic (covers most of the SM preferred range) but: is this enough?


BsJ/ CDF prospected harvest:

(LowPt andNOT Scenario A)

The total CDF BsJ/ yield is: ~ 1500 / fb-1

~ 9000 in 6 fb-1 (hopefully by 2008! Before LHCB & BTEV)Will achieve: ()~0.010.03

N(BsJ/) ≈ 100 in the hadronic trigger!

(Only 20% are in common with Di-muon J/ trigger)

As measured from 180pb-1 DATA

N(BsJ/) ≈ 180 in the Di-Muon trigger! +

CDF Roma


Conclusions: from CDF Bs physics

• ms in the SM range, will be measured with 3.2 fb-1 in the golden(high resolution channels). New limit possible soon from semi-leptonic decays.

• ss at % level from BsJ/ before next generation B experiments.

• Several BsPV, VV modes under study from now on, QCDF tests CPV studies, polarizations.

• Constrain beyond SM theories with rare B decays Bs,d , K*,


BACKUP slidesBACKUP slides


CDF data tacking performanceData-Taking Efficiency Integrated Luminosity

Detector efficiency ~85-90%


CDF II particle ID handles

TOF PID

dE/dx PID

•Specific Ionization of charged particles (dE/dx) measurement in the COT gas chamber.

•Time of flight measurement with the new scintillator bars detector (TOF) at R=1.4m with a TOF = 100 ps

p

Total K/ separation power of at least 2 for momentum up to 1.6 GeV/c with TOF

And at least 1 for momentum up to 4-5 GeV/c with TOF + dE/dx


CDF Trigger System Overview

• Crossing: 396 ns: 2.5 MHz

• Level 1: hardware– Calorimeter, Muon, Track

– 15kHz (reduction ~x200)

• Level 2: hardware + CPU– Cal cluster, Silicon track

– 300 Hz (reduction ~x5)

• Level 3: Linux PC farm– ~ Offline quantities

– 50 Hz (reduction ~ x6)


B hadron Lifetimes in exclusive decays

J/ trigger •Clean•Fully reconstructed•Lifetime unbiased•“Low statistics”

J/

K+B+

B+ J/ K+

J/ K*+

B0 J/ K0* J/ Ks

b J/ c

B0s J/

Lifetime measurement:•Reconstruct decay length•Measure pT of decay products

)(

)(

BP

BmLLc

T

xyxy


Exclusive B+J/X LifetimesSimultaneous fit of Mass and c distributions


Resolutions with current 180pb-1 sample

• Acp(Kπ) to 7%• BR(BsKK) to 15%• Yields: 130pb-1 CDF = 80fb-1 Babar

Risoluzioni attese 180pb-1 65pb-1Bdpipi ± 0.024 ± 0.05BdKpi+barBdKpi ± 0.028 ± 0.05BsKpi+barBsKpi ± 0.024 ± 0.05BsKK ± 0.026 ± 0.06ACP ± 0.071 ± 0.14BsKK/(BdKpi+barBdKpi) ± 0.053 ± 0.13Bdpipi/(BdKpi+barBdKpi) ± 0.046 ± 0.10

Bd =144 23

BdK =576 27

CDF Run II Preliminary

Current single best measurement(BaBar)

(AdirCP )

B0d K+ -

0.035

1000 4000Integrated luminosity pb-1


B- D0K- @ CDF

8 % D0K-

(fixed but excluded from the fit)

• 8 %2855 = 228 D0K- events expected in 180 pb-1 • D0

CP (KK+pp) = 228 (9.96 % + 3.6 %) = 31 events

180 pb-1 all triggers: 2855 D0- only channel with K good with PID

D0K- sits on the tails of several B channels


… others and Bs

• Bd D0KS(L) (BR 5.0 10-5, Belle): tan() in an

unambiguous way, requires time dep. analysis, tagging.• Bs DsK

+ measures (), requires time dependent analysis, tagging. BR is already a paper level analysis.

• Bs D0KS(L) ,D0K* (color suppressed by 1/9, contributes to ms)

DsK+ fixed

in the fit


Semileptonic Bs samples

Bs l Ds X

Ds

Ds KsK

Ds K*KDs

Yield/Lumi ~ Run I x3

S/N ~ Run I x 2

universita' "la sapienza", 11/6/2004 sandro de cecco - infn roma 11 sandro de cecco...

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