SLAC 06/12/03 EPAC meeting Marcello A. Giorgi1 BABAR Status and Outlook Marcello A. Giorgi on behalf...

SLAC 06/12/03 EPAC meeting

Marcello A. Giorgi 1

BABAR Status and Outlook

BABAR Status and Outlook

Marcello A. Giorgi

on behalf of BaBar Collaboration

EPAC meeting - SLAC



BABAR

DCH

EMC

DIRC

COIL

IFR

SVT

The The BBAABBARAR CollaborationCollaboration

10 Countries 75 Institutions 579 Physicists

Canada China France Germany Italy The Netherlands Norway Russia United Kingdom USA

[4/18] [1/5] [5/55] [3/30] [11/101] [1/2] [1/3] [1/9] [10/66] [38/290]



New environment: high luminosity asymmetric collider

1)Search for CP violation in B meson decays largely predicted by the Standard Model

2)Test extensively at this low energy scale the Standard Model by measuring precisely enough quantities to impose constraints on the Standard Model parameters

CP in b sector has been established by BaBar and Belle

TRY to open windows on new Physics beyond Standard Model

More precise CKM measurements, Rare B decays, Charm study, Tau rare decays .

BaBar Physics GOALS



CP in Standard Model

CKM quark mixing matrix

2

2 4

3

23

2

( )

(

11

21

1 ( )2

11 )

ud us ub

cd cs cb

td ts tb

A iV V V

V V V V A O

V V VAA i

bulB() l

CP Violating phase

BD(*)lbcl

B() B0 Mixing

Unitarity



Experimental ingredients: BaBar optimized for time dependent CP

asymmetries

+e-e

z

Brec

Btag 4s

(4S) = 0.55

Coherent BB pair

B0

B0

Start the Clock

zc

zt

1

Tag vertex reconstructio

n

Tag vertex reconstructio

n

FlavorTaggingFlavor

Tagging

Exclusive B Meson and Vertex Reconstruction

Exclusive B Meson and Vertex Reconstruction

0sK

J/



Time dependent rate,flavor mixing and CP,T,CPT

Time dependent rate:dN exp(–|t|/B) ( 1 ± D (S sin(mt) - Ccos(mt)) ) R

2

2

21

1

1

Im2

CS

CPV in Mixing -DecayCPV direct

cp

cp

cp A

A

p

q___

D is the mis-tag dilution

R is the time resolution

0B

0B

CPfCP

mix

ing decay

CPfA

CPfA

t

2

22

im

iMz

z0 CP & CPT violation

1p

q CP and T Violation in mixing

42

2

105sin41 t

c

m

m

p

qSM



Fit without the “usual assumptions”!Fit BCP and B0flavor eigenstates (/, q/p, z and CP left FREE)

sgn(Re ) 0.008 0.037(stat.) 0.018(syst.) [ 0.084,0.068]

1.029 0.013(stat.) 0.011(syst.) [1.001,1.057]

(Re ) Re 0.014 0.035(stat.) 0.034(syst.) [ 0.072,0.101]

Im 0.038 0.029(stat.) 0.025(syst.

CP

CP CP

q p

z

z

) [ 0.028,0.104]

90% C.L.

The “usual assumptions”work!

Direct limit on Test of CPT invariance Indirect CP in mixing

Preliminary



LOOK for N.P. in Loops?

from charmonium channelsResults are so far CKM

compatible but…

s

s

s

d

KS

s

s

s

dsin(2) = 0.741 ± 0.067stat ± 0.033syst

?



B0 +- sin2eff

With incomplete information on Penguin contamination:• Measure S and Cfrom

both sinmt and cosmt terms .

• Compare with predicted S and Cvalues for given , , |P/T|, and . Assume for instance:

From sin2eff to sin2?

isospin analysis, needs B0

22

3021

28.0/

26

)97(

TP

cf. Gronau and Rosner, Phys. Rev. D65, 093012 (2002)

BABAR

Belle 1

Belle 2



B0 ) the CP fit• Time integrated direct CP:

• Time dependent CP:

• Asymmetry between rates:

08.017.028.0 KCPA

03.008.018.0 CPA

04.018.036.0 C

03.024.019.0 S

03.00.250.15 S

04.00.28 0.180.19-

C

First step towards in B. Full Dalitz analysis in progress.

Preliminary



Toward : the BD0CP K approach

sin2 from the triangles (Gronau-Wyler method):

BaBar measurements:

2

DD

:seigenstate CP are Dwhere00

CP

0CP

D

)(2 0 KDBA CP

)(2 0 KDBA CP

)%20.035.031.8()(

)(0

0

DBBF

KDBBFR

)%5.06.18.8()()(

)()(00

00

CPCP

CPCP

CP DBBFDBBF

KDBBFKDBBFR

06.017.006.0)()(

)()(00

00

KDBBFKDBBF

KDBBFKDBBFA

CPCP

CPCP

CP

Preliminary



|Vub| from fully tagged SL decays

Brecoil

BrecoD(*)

Y(4S) l

Xu

Recoil of fully reconstruted B (~4KB /fb-1)

bul signal:MX (< MD)( ~ 60-80%)

S/B 1.7: good!

Preliminary



Rare B decays

b u : tree, CKM suppressed

b s,d: Radiative (QCD, EM, EW) Penguins FCNC

Leptonic decays: B0 l+l-, B , B l+, …

tree

QCDpenguin

EMpenguin

EWpenguin

probes b inside B

Possible New Physicssignatures: rates and phasesfrom virtual particlesin the loops



Not only B Physics in BABAR !

A new state decaying into D+s(1970) and 0

has been discovered by us and recently confirmed by CLEO!

D+s 0

D+sK+K- + D+

sK+K- + 0



An example: D mixingVery small in the S.M. 2 additional suppression

A window for new physics

Charm, tau discovery potential

limit3

005.0 222

SU

mmm Wds

lepton number is violated inmany extensions of the S.M.(present limits, O(10-6) are not far from some model predictions)

D0

c

c

u

ud,s d,s

W-

W+

Vcd,cs

V*cd,csV*

ud,us

Vud,us

D0

“long distance” -iy

“short distance” x

D0 D0

K-,

K+,+

Another example: lepton flavour violation

S.M., extended to include mixing and mass:

BR( O(10 - 34)



Luminosity: Present and Future

FY2002

FY2003

Longerterm

So far in Run 3: On peak 30.02 fb-1

Off peak 2.57 fb-1

By the end of the decade: 12 ab-1

Summer 2002 and Winter 2003:Run 1 + Run 2On peak 83.9 fb-1

Off peak 9.6 fb-1

92 M BB pairs

Summer 2003:Run 3add 40 fb-1

By end 2006: 500 fb-1



Next about sin2• Extrapolated statistical and systematic uncertainties

Statistical uncertainty Golden modes

Param. Channel (stat)/(syst) 0.08 ab-1

(stat)/(syst) 0.5 ab-1


sin2 Im(+) S S S

J/KS Golden D*D* J/0 KS ’ KS

0.08 / 0.03 0.07 / 0.03 0.43 / 0.13 0.49 / 0.16 0.50 / 0.09 0.34 / 0.03

0.037 / 0.018 0.031 / 0.018 0.16 / 0.07 0.20 / 0.20 / 0.14 /

0.018 / 0.018 0.015 / 0.018 0.08 / 0.03 0.10 / 0.10 / 0.07 /

21 L

1syststat ab2at L

(*)

(*) This syst error of 0.018 is dominated by DCS decays of charm in K tagged events. Lepton tag is not affected !



What next for Sin 2

Pure penguin process B Ks

The present value with 80 /fb is:

S=sin2=-0.19-0.50+0.52 stat.±0.09syst.

With 2/ab (S) goes down to 0.1

But also B ’ K and B K K K

NEW PHYSICS ?

New quanta in the loop?



Results (0.08 ab-1) for BFactories

Param. Channel (stat)/(syst) 0.08 ab-1



S C

+-

0.34 / 0.05 0.25 / 0.04

0.12 / 0.03 0.10 / 0.03

0.06 / 0.05 /

Extapolations for sin2eff

Extrapolated errors (BaBar)

Param. BaBar Belle S C

0.02 0.34 0.05 -0.30 0.25 0.04

-1.23 0.41 (+ 0.05-0.07) -0.77 0.27 0.08



r=0.2 (2ab-1), sin2fit: sin2

from B-D0(CP)K-: projections

Recent experimental results (BaBar)

Toy MC projections: (Fit unreliable for r = 0.1)

02.029.002.1)(

)(

0

11

KDB

KDBn

)02.026.072.0()(

)(

0

11

KDB

KDBp

r=0.3 (0.5 ab-1), sin2fitsin2

08.023.017.0 CPA

ACP=0.174 0.031

r=0.2 =60o =30o

(2ab-1)

KKD0500

)1.0(

)(

)(

0

0

O

KDBA

KDBAr



projected errors for |Vub|

Selection:One B reconstructed in D(*)XLepton momentum and neutrino massKaon veto, charge balanceFit Mx with constraints

MX distribution fit:

bul, bcl, backgroundErrors:

Statistical L(ab-1) = 0.08 0.5 2.0 10 stat(%) = 7.0 2.8 1.4 0.6

Experim. Systematic ~5% (now) 2.5% (bcl bkgd)

Theoretical ~ 9% ((mb)=90MeV) 5% (b ulabove cut)

Mx (GeV)



B beam method

“B – beam”

BrecoD(*)

Y(4S) l

h

B factories present an unique peculiarity. Events are pure B B and a full reconstruction of one side allow to treat the other as a pseudo B-beam. The study of rare decays with neutrinos are becoming possible with very high integrated luminosity.



Integrated luminosity vs physics

2sin

1 abLdt1.0 0.1 .105.0 0.2

BaBar2006 2009 ?

cbub VV 2sin2sin llKllX s

*, *, KX s

,

2002

Continuous improvement



Some comments about comparison with Hadron machine expts.

CKM parameters BABAR/Belle BTeV/LHC-B 2 ab-1 107 s

Sin(charmonium) 0.015stat/0.018syst 0.025/0.014Sin (penguins bsss) 0.10 stat ----in S eff(B0 0.06 stat 0.024/0.056

eff – ( B0 ) <10° ----Sin() (B0 D* ) 0.15 ---- (B DK) 7° <10°/<19°|Vub| 1.4%+ Th. Unc.(now better 10%) ----

Of course Bs mixing and decay can be studied well at hadron machines ( and a lot of good physics from Bs)



Rare decays - SummaryChannel BF BTeV/LHC-B (107 s) BABAR/BELLE (2 ab-1)

bs 3.3±0.3 10-4 ---- 44.0K 6.8K(Btagged)

BK*10-5 25K 24.0KB ()10-6 ---- 1.2K

bs±1.5 10-6 3.6K 1.2Kbse+e- 1.4KBK*±1 10-6 2.2K/4.5K 0.5KBK*e+e- 0.6K

bs±0.9 10-5 ---- 30BK*10-6 ---- 6

B10-5 ---- 70B10-735

Limit< 10-8

Bfactory and hadron machine measurements are complementary !

Rates…Fully

reconstructed B on the other side are used

The so called

B beam option

Asymmetries!



What about Detector? SVT!BABAR is a VERY good detector: very difficult to improve it!! (On IFR barrel is the only major intervention needed)

SVT is 98% efficient. No degradation due to irradiation has been observed so far

SVT so far tested for rad hardness up to 4 Mrad (OK!) rad tests are going on.

Partial SVT replacement is considered by 2005. Almost 50% of modules built as spare.



Instrumented Flux Return• Instrumented Flux Return

– 2000 m2– 342 barrel RPCs– 432 endcap RPCs– 32 cylindrical RPCs

• Electronics– 3300 Front end cards

• ~ 40 mV threshold• 16 channels connected to

alternate strips

• Gas– 35% Freon 134a, 4.5%

iso-butane, 60.5% Argon

– 1-3 volume changes/day• High Voltage

– > 50 10 kV HV pods



BABAR RPC• Operates in limited streamer mode• Parallel high resistivity plates

(Bakelite 1011 -1012 cm )• Graphite ~100 k/ • RPCs were filled 3 times with a

mixture of 70% linseed oil and 30% n-pentane and dried by air for several days.

• Changes from L3 RPCs– Polycarbonate buttons with lip

replaced G10 cylindrical button– Thicker oil layer– Single layer with strips on both

sides– No mechanical envelope– Nonflammable gas - low iso-

butane %, CBrF3 replaced by Freon 134a C2H2F4

Efficiency of barrel RPCs after production ~97%



1999• IFR complete May 99 • RPC efficiencies good• Warning signs

– Some RPCs with > 100 mA were disconnected

• With collision data– HV current limitations force

reduction in # of RPCs• Average Efficiency low

~85%• Barrel is about 50% of total IFR

coverage• Forward Endcap about 40%• Decision was taken in 2000 to

upgrade the Forward Endcap with new RPC (higher QA/QC level) and with more absorber.



Absorber Segmentation

7 layers 2 cm

1 layer 7 cm

2 layers 9 cm

2 layers 13 cm

2 layers 10cm

total 85 cm

New Forward EndCap from nov 2002

Terminology: 19 slots and 15 RPC layers

RPC belt

Slot18/195 brass layers(slot 8,10,12,14,16)



RPC problems (post mortem photo)

Gas inlet Debris

Whiskers

Excess oil

Opposite side

Linseed oil – uncured oils move under HV and warm temperatures

Graphite layer develops high resistance

Internal debris and whiskers

5% of barrel has HV problems before New HV distribution

~50% of the barrel modules leak (many have normal efficiency)

Front End electronics problems



IFR Barrel Upgrade

Muon selectors losing efficiencyA committee was setup in september 2002 to evaluate physics motivation for a IFR upgrade and technology.B.Ratcliff and C.Hearty were chairing the committee.After 3 months the committee Presented its recommendations to BaBar.

Many RPCs die since 1999. Fraction effectively dead is now almost 40%



Committee proposes to increase the thickness of the absorber and to replace the bakelite RPC with a more robust detector (Limited StreamerTube).

INSTALLATION in 2004 & 2005

We have submitted a proposal and ask for your approval .

FINAL DOCUMENT May22,2003



SummaryBabar apparatus is generally very robust and can cope

with high luminosity environment above 10 34 . Decision has been taken to upgrade the IFR Barrel with a different technology well established and robust (LST).

Preliminary measurements of pure penguin processes for sin2, measurements of Vub, B->DK, B->includingDalitz plot analysis.

FUTURE – In 2005 complete the installation of the IFR Barrel. Install the Spare modules of SVT, to replace the heavily irradiated modules on horizontal plane.

Approach the precision measurement with 0.5/ab of integrated luminosity . Towards more than 1.0/ab explore possible openings for new physics.Study of CP asymmetries but also rare decays in b, c and tau sectors.

Profit from full reconstruction of one B : “ Pseudo B beam”



BACKUP SLIDES



Flavour mixing and CP,T,CPT

m=mH-m L 2|M12| 0.5ps-

1

1/ 1.6 ps

=H-L |M12|Re (12/M12)

SM

1p

q CP and T Violation in mixing

42

2

105sin41 t

c

m

m

p

q

As in K sector where k=(p-q)/(p+q) ~O(10-3)

SM



Flavour mixing and CP,T,CPTCP an CPT conservation if H11=H22

2

22

im

iMz

2

2211 MMM

2

2211

t)),BB((Probt)),BB((Prob_

0_

000

0z

CP and CPT VIOLATION

Assumptions made in the usual sin2 analysis:0H L

12 122

12 122

1i

i

Mq

p M

11 22 11 222

2

( )0

i

i

M Mz

m



Time Dependent CP asymmetries

CP eigenvalueMi

tdtb

tdtb eVV

VV

p

q 2

*

*

Amplitude ratio B0fcp/B0fcp

B mixing

Measured from data (Flavour sample)!

D mis-tag dilutionR time resolution

CPV in mixing-decay interference direct CPV

dN exp(–|t|/B) ( 1 ± D (S sin(mt) - C cos(mt)) ) R

2

2

21

1

1

2

CS

Flavour tag



Search for B+ +

B candidate Semileptonic tagD0

Y(4S)

cosB,Dlfor B D0X tags

Total signal-side neutral energy

Semileptonic tags: BF(B+ +) < 4.910-4 (90% CL)Fully reco tags: BF(B+ + ) < 7.710-4 (90% CL)

combined: < 4.1 10-4

Preliminary



RPC efficiency 00

-1.4% /month

-1.4% /month

-0.56%/month

Gas change



Detector studies• Realization that the RPC

efficiencies did not recover after cooling spurred detector studies– Efficiency was computed as a

function of position

• Limited tests were carried out during accesses or on a few chambers– Lowered barrel temp. to 17 C. – Reversed HV– Increased gas flow– Lowered discriminator threshold– Put weights over inefficient regions

• No effect• Gas composition was regularly

tested– No evidence of water vapor

A wide spread of plateau curves were measured.



RPC radiography The RPC efficiency was mapped in 2D showing irregular regions of reduced efficiency.

D. Piccolo



Occupancy plots for run 38637

Brick shields ~.8 m from L 16

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi1 BABAR Status and Outlook Marcello A. Giorgi on behalf...

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Transcript of SLAC 06/12/03 EPAC meeting Marcello A. Giorgi1 BABAR Status and Outlook Marcello A. Giorgi on behalf...