B factories physics reach
This presentation is the property of its rightful owner.
Sponsored Links
1 / 55

B-Factories: Physics Reach PowerPoint PPT Presentation


  • 78 Views
  • Uploaded on
  • Presentation posted in: General

B-Factories: Physics Reach. Luminosity CPV and CKM Rare B decays Conclusions. Livio Lanceri – Univ. and INFN Trieste INFN-CSNI – LNF, February 4, 2003. Discovery potential at the B factories. CKM and Unitarity Triangle SM predicts a pattern of CPV, from phase in the CKM matrix

Download Presentation

B-Factories: Physics Reach

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


B factories physics reach

B-Factories: Physics Reach

Luminosity

CPV and CKM

Rare B decays

Conclusions

Livio Lanceri – Univ. and INFN Trieste

INFN-CSNI – LNF, February 4, 2003


Discovery potential at the b factories

Discovery potential at the B factories

  • CKM and Unitarity Triangle

    • SM predicts a pattern of CPV, from phase in the CKM matrix

    • B factories can measure both angles and sides of the Unitarity Triangle

    • New phases from New Physics may reshape the UT

  • Rare B Decays

    • CKM suppressed (tree b  u), Radiative Penguins (QCD, EM, EW), leptonic B decays

    • Common feature (Penguins, leptonic): New Physics signatures from rates and asymmetries (new virtual particles in the loops)

  • Charm, tau

    • Examples: D mixing and lepton number violating  decays

    • Very small in SM  windows for New Physics

L.Lanceri - B-Factories: Physics Reach - CSNI


Experimental ingredients

Inclusive tag (lepton, K, …): tag(1-2w)2 28%

(Exclusive tag: tag  0.10.2%)

z(CP)

z(tag)

rec  1540%

< z >  260 m

z (RMS) 190 m

Experimental ingredients

Asymmetric B factories optimized for measurements of time-dependent CP violating asymmetries

OK also for other measurements (rare B decays, …)

Open trigger! No B physics losses at trigger level

High efficiencies, small bkgd

Unique tool at B factories: exclusive B tagging with fully rec. B (“single B beam”)

Luminosity is a key factor

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories experiments and luminosity

BABAR/PEP-II

Record peak luminosity:

4.6 x 1033cm-2s-1(~5 BB/s)

max lumi/24h: 303 pb-1

total recorded lumi to date: ~0.1 ab-1 (~10% off-peak)

Restarted end Nov.2002 after 4 months shutdown (Forward IFR upgrade)

Belle/KEK-B

Record peak luminosity:

8.2 x 1033cm-2s-1(~8 BB/s)

max lumi/24h: 433 pb-1

total recorded lumi to date: ~0.1 ab-1 (~10% off-peak)

Restarted in January 2003 after vacuum loss forced stop in December

B-Factories: experiments and luminosity

  • c.f. integrated luminosity for

    • Argus (1983-1987): ~100 pb-1

    • CLEO (1981-2000): ~16 fb-1

L.Lanceri - B-Factories: Physics Reach - CSNI


Pep ii without upgrades

PEP-II without upgrades

1.1 ab-1

1.6 x 1034

peak

integrated

0.5 ab-1

2006

2009

L.Lanceri - B-Factories: Physics Reach - CSNI


Pep ii upgrade scenarios

NO

(Super-KEKB?)

Minimal upgrade

Feasible from 2005

Shut-down  3 months

0.40.5 ab-1/year

Limited cost

SuperPEP/SuperBaBar

Year 20...?

New collider,

(and new detector…)

Snowmass: 370M$

2ab-1

in 2009

PEP-II upgrade scenarios

From J.Seeman/SLAC

L.Lanceri - B-Factories: Physics Reach - CSNI


Path to higher pep ii luminosity

Path to higher PEP-II luminosity

Luminosity4.6E331E342E344E34Units

I+ 180027003600 4500mA

I-95014001760 2000mA

Beta y*11.597 4.5mm

Beta x*505050 50cm

Bunch Length 1.3 1.00.8 0.5cm

# bunches 792130015001600

Vert. Emitt. 2.51.4 1.10.7nm

Horiz. Emittance40/5030/4532/4740/48nm (+/-)

Crossing angle000~+/-8mrad

Tune shifts (x/y)7.5/4.58.0/5.78.2/6.08.4/6.3x100

Number RF stations7101315

Date hardware readyJan 02Dec 02Dec 04Nov 05

Date for luminosityJun 02July 03Dec 05Dec 06

(J.Seeman, BaBar Collaboration meeting, Sept.2002)

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar long term planning tf

BaBar Long Term Planning TF

For the 4x1034 PEP-II upgrade:

We studied the physics reach in some channels for:

0.5 ab-1 (2006),

2.0 ab-1 (end of the decade)

And: Interest/need of an accompanying BaBar detector upgrade ?

(Conclusion: only Barrel IFR)

Most extrapolations reported here come from the preliminary report of the TF

L.Lanceri - B-Factories: Physics Reach - CSNI


What about kek b belle upgrades

What about KEK-B/Belle upgrades ?

EoI (January 2002): Super KEK-B, L = 1035cm-2s-1

- LER: e- , I = 10A; HER: e+, I = 3A Linac upgrade (e-  e+)

- Vacuum system (ante chambers); RF system (52 cavities, 12SC)

- 15 mrad crossing, final focussing

Total cost (KEK-B + Belle):

 400 M$

EoI preliminary plan:

Present plans: … ??

Workshop at KEK, Feb.2003

L.Lanceri - B-Factories: Physics Reach - CSNI


Cpv and ckm phases

CPV and CKM: phases

sin2

sin2


B factories physics reach

CP eigenvalue

Amplitude ratio B0fcp/B0fcp

B mixing

CP asymmetry: Time Dependence

CPV in mixing-decay interference direct CPV

dN exp(–|Dt|/tB) ( 1 ± D (Ssin(DmDt)-Ccos(DmDt)) )  R

Flavour tag

D mis-tag dilution

R time resolution

Measured from data (Flavour sample)!

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar sin2 b results

BaBar, sin2b: results

Charmonium modes

on-peak: 81.9 fb-1

off-peak: 9.6 fb-1

 89 M BB pairs

sin2b = 0.755  0.074

sin2b = 0.723  0.158

sin2b = 0.741  0.067  0.034

tagged CP sample: 2631

flavor sample: 25375

Modes with Penguins

Yield

(pure Penguin!)

in Standard Model

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar sin2 b systematics

decays with charmonium:

Source

dsin2b

CP and Mix BG

DCS decays, tag side

0.017

0.008

Klong BG

0.015

Dt meas. and RF

0.017

Signal Dilutions

0.012

Fit bias correction

0.010

B lifetime

0.004

Dmd

0.003

Total

0.034

BaBar, sin2b: systematics

Asymptotic

0.004

0.008

0.003

0.010

0.010

0.003

0.003

0.003

0.018

Using only

lepton tags:

0.01

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 b projected errors babar

sin2b: projected errors (BaBar)

  • Extrapolated statistical and systematic uncertainties

    Statistical uncertainty

    For “golden” modes only

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

u

b

t

d

p-

p-

u

d

B0

B0

b

u

u

p+

d

d

p+

d

d

Mixing + T:

b+g

P:

-b,d

sin2eff fromB0+-

Observables in +-

CP asymmetry (time-dependent)

Extra weak phase –b, strong phase d, and |P/T|, modify a by k

  • : from isospin analysis

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar and belle s pp and c pp

BABAR

Belle 2

Belle 1

BaBar and Belle: Spp and Cpp

With incomplete information

(no isospin analysis):

  • Measure Spp and Cpp from both sinDmDt and cosDmDt terms .

  • Compare with predicted Spp and Cpp values for given a, b, |P/T|, and d. Assume for instance:

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

L.Lanceri - B-Factories: Physics Reach - CSNI


Results and extrapolations for sin2 eff

Results and extrapolations forsin2eff

Results (0.08 ab-1)

Extrapolated errors (BaBar)

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 isospin analysis gronau london

sin2: isospin analysis (Gronau & London)

Need flavor tagged rates for

+-, 0, 00

BaBar:

L.Lanceri - B-Factories: Physics Reach - CSNI


Upper bounds on 2 eff 2

Grossman-Quinn bound:

BaBar, extrapolations:

vs BF(00),

at fixed Luminosity

Upper bounds on = 2eff-2

BaBar, present data:

Small gain

with lumi

Most powerful

at small BF

L.Lanceri - B-Factories: Physics Reach - CSNI


Isospin analysis projections 1

BR(B`gp`p0) = 4.1x10-6

BR(B0gp+ p-) = BR(B0gp+ p-) = 4.7x10-6

Isospin analysis: projections - 1

  • Sensitivity to : toy MC with BaBar detector

  • Assumptions (example):

NB: 4-fold ambiguity !

<BR(Bgp0p0)> = 2.0x10-6

L = 0.5 ab-1

L = 2.0 ab-1





L.Lanceri - B-Factories: Physics Reach - CSNI


Isospin analysis projections 2

Isospin analysis: projections - 2

  • BaBar sensitivity on : summary

    • (4-fold ambiguity not included)

  • Assumptions:

    • 00 reconstruction efficiency: rec = 0.18

    • For each B tagging category:

      • Tagging performance , D = 1-2w

      • Bkgd effective cross sect. B (106)

L.Lanceri - B-Factories: Physics Reach - CSNI


Quasi 2 body b 0 analysis

Quasi-2-body B0  analysis

hep-ex/0207068

Acp

81.9 fb-1

L.Lanceri - B-Factories: Physics Reach - CSNI


3 body 0 dalitz analysis for

B0+– - B0–+

Interference

Region

B0+– - B000

Interference

Region

3-body (+-0) Dalitz analysis for 

  • 11 parameters (“fundamental”):

  • remove overall phase & normalization: 9 parameters

Suffers from mirror solutions

  • 10 parameters (“amplitudes”):

  • remove overall phase & normalization: 8 parameters

  • obtain fundamental parameters from subsequent fit.

No mirror solutions. Does not depend on particular weak phase decomposition

…work in progress

L.Lanceri - B-Factories: Physics Reach - CSNI


At the b factories

 at the B factories

  • sin(2) from fully/partially reconstructed B  D(*)

    • Analysis in progress

  • Rates and asymmetries in B   K, KK

    • Require theoretical assumptions

  • Promising developments: 3-body decays, Dalitz analysis (work in progress)

    • B  D(*)K(*), D(*)Ks, DKs, D(*)K(*), …

  • Most advanced analysis in BaBar: B-gD0(CP)K-

    • Sensitivity extrapolations from preliminary results

81.2 fb-1

L.Lanceri - B-Factories: Physics Reach - CSNI


From b g d 0 cp k

g

(Gronau-London-Wyler)

 from B-gD0(CP)K-

Observables: n1, p1, n2, p2

Theor. parameters: , r, 

L.Lanceri - B-Factories: Physics Reach - CSNI


From b g d 0 cp k projections

 from B-gD0(CP)K-: projections

Recent experimental results (BaBar)

Toy MC projections:

(Fit unreliable for r = 0.1)

r=0.3 (0.5 ab-1), sin2g = 0.75  fit: sin2g = 0.720.23, g = (59.910.2)o

r=0.2 (2ab-1), sin2g = 0.75  fit: sin2g = 0.710.14, g = (58.57.4)o

r=0.2 g=60o Dd=30o (2ab-1)

ACP=0.174 0.031

L.Lanceri - B-Factories: Physics Reach - CSNI


Ckm triangle sides

Vcb (Vub)

(u)

|Vtd/Vts|2

(,…)

CKM Triangle: sides


V ub from fully tagged sl decays

Breco

Brecoil

D(*)

Y(4S)

l

p

n

|Vub| from fully tagged SL decays

Semileptonic decays

on the recoil of

fully rec. B

(~1KB0 /fb-1,

~2KBch. /fb-1)

To separate bul

MX(< MD)

( ~ 60-80%)

(or other variables:

P*l, q2)

Xu

L.Lanceri - B-Factories: Physics Reach - CSNI


Projected errors for v ub

projected errors for|Vub|

Selection:

One B reconstructed in D(*)X

Lepton momentum and neutrino mass

Kaon veto, charge balance

Fit Mx with constraints

MX distribution fit:

buln, bcln, background

Errors:

Statistical L(ab-1) = 0.08 0.5 2.0 10

sstat(%) = 7.0 2.8 1.4 0.6

Experim. Systematic ~5% (now)  2.5% (bcln bkgd)

Theoretical ~ 9% (s(mb)=90MeV)  5% (buln above cut)

Mx cut, b quark Fermi motion from b  s, Mx bins

Further improvements from lattice QCD, restricted phase space

Mx (GeV)

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

Towards Vtd/Vts

Extrapolation

0.5 ab-1

2 ab-1

From experience gained with present data

0.5 ab-1

2 ab-1

Significant gain if one can reduce

the background by factor 2

10% error due to long range effects

to be compared to 6% for Dmd/Dms

L.Lanceri - B-Factories: Physics Reach - CSNI


Rare b decays

QCD

penguin

bu tree

EM

penguin

Rare B decays

EW

penguin

leptonic


Charmless decays direct cp violation

Charmless decays: Direct CP violation?

Time-integrated CP asymmetries:

No evidence for direct CPV yet

Theoretical expectations:

Tree + Penguin: ACP 10%

Pure Penguin: ACP 1%

Present sensitivity (most channels)

statACP 10% systACP 12%

Charge asym.

L.Lanceri - B-Factories: Physics Reach - CSNI


Ew penguins babar

Signal

Box

Sideband

m(D0)Rec-m(D0)PDG (m(D0))

Remaining neutral Energy (GeV)

EW Penguins (BaBar):

Exclusive measurements:

85M BB pairs

Inclusive (bsl+l-)

in progress

Preliminary

Theory (SM): B(B+K+)  3.8 x 10-6

56M BB pairs, fully reco. SL tag

2 events observed (2.2 bkgd expected)

B(B+K+)  9.410-5 (90% CL)

L.Lanceri - B-Factories: Physics Reach - CSNI


Leptonic decays babar

Leptonic decays (BaBar)

  • Already published, to be updated (Run1+2)

    • BF(B ) < 1.7 10-6 (90% CL); int.lumi. 19.4 fb-1

  • ICHEP 2002 (Run1+2):

    • BF(B  e+e-) < 3.3 10-7 , BF(B  +-) < 2.0 10-7 ,

    • BF(B  +e-) < 2.1 10-7 (90% CL)

  • New analyses on B+ + (Run1+2),with:

    • Lepton tag or Fully reconstructed hadronic tag

    • Sensitivity competitive with existing exptal limits (LEP: 5.7  10-4)

L.Lanceri - B-Factories: Physics Reach - CSNI


Some extrapolated yields babar

Some extrapolated yields (BaBar)

  • Extrapolated yields for B+ + andB+K+

Present analysis: backgrounds:

 280 events in 80fb-1

K 2 events in 56MBB pairs

L.Lanceri - B-Factories: Physics Reach - CSNI


Rare decays summary

Rare decays - Summary

Projections from Snowmass 2001: reconstructed events

Efficiencies from BaBar/Belle; some numbers should be updated

(*) “B exclusive tag” (assuming   0.2%)

Asymmetries!

Rates…

L.Lanceri - B-Factories: Physics Reach - CSNI


Conclusions outlook

Conclusions & Outlook

  • B factories discovered CP violation in B decays and are measuring sin2 with increasing accuracy

  • Each of the two B factories integrated a luminosity of about 0.1ab-1 and should integrate 0.5ab-1 by 2006; depending on the machine upgrade options, about 2ab-1 per experiment could be within reach by the end of the decade

  • Such an increase in integrated luminosity will significantly extend the physics reach of the B factories, both for the Unitarity Triangle, and for rare B decays

  • Other topics, including charm and tau physics, are part of the physics program (see backup slides)

L.Lanceri - B-Factories: Physics Reach - CSNI


Backup slides

Backup slides


Charm

“short distance”  x

Vcd,cs

W-

Vud,us

c

u

D0

d,s

d,s

D0

u

c

V*ud,us

W+

V*cd,cs

“long distance”  -iy

K-,

D0

D0

K+,+

Charm

An example: D mixing

Very small in the S.M.

  • 2  additional suppression

     A window for new physics

    Sensitivity estimate (BaBar)

    1, including statistical and systematic uncertainties

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

lepton number is violated in

many extensions of the S.M.

(present limits, O(10-6) are close

to some model predictions)

tau

Another example:

lepton number violation

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

BR(t) ~O(10 - 34)

BaBar sensitivity, projections:

L.Lanceri - B-Factories: Physics Reach - CSNI


B physics accelerators

B physics: accelerators

Hadron colliders:

Higher cross sctions, but: higher bkgd, lower efficiency

B-factories:

Luminosity is the critical factor

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

BaBar Detector

EMC

6580 CsI(Tl) crystals

e+ (3.1GeV)

1.5T solenoid

DIRC (PID)

144 quartz bars

11000 PMs

Drift Chamber

40 stereo layers

e- (9GeV)

Silicon Vertex Tracker

5 layers, double sided strips

Instrumented Flux Return

iron / RPCs (muon / neutral hadrons)

  • SVT: B vertex z resolution ~70 microns

  • Tracking: (pT)/pT= 0.13%  pT0.45%

  • DIRC: K- separation > 3.4 for P < 3.5GeV/c

  • EMC: E/E = 1.33%E-1/4 2.1%

L.Lanceri - B-Factories: Physics Reach - CSNI


Cp asymmetries sensitivity

CP asymmetries: sensitivity

  • Error on the diluted CP asymmetries (Aobs= DACP)

    • Number of events:

    • Efficiencies:

    • Dilutions:

  • B factories

    • Small cross section:

    • higher efficiencies and better dilutions   D2

L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

Bflav

Mixing

sample

BaBar, sin2b: “golden” modes, now

CP states with charmonium: to measure sin2

2641 tagged events

on-peak: 81.9 fb-1

off-peak: 9.6 fb-1

 89 M BB pairs

c1 Ks

J/Y Ks

(Ks p+p-)

Flavor states:

to measure mixing and D, R

J/Y Ks

(Ksp0p0)

25375 events

Y(2s) Ks

J/Y K*0

(K*0  Ksp0)

J/Y KL

hcp=+1

L.Lanceri - B-Factories: Physics Reach - CSNI


Cp violation sin2

CP violation: sin2

sin2b = 0.741  0.067 (stat)  0.034 (syst)

hcp=-1

hcp=+1

sin2b = 0.755  0.074

sin2b = 0.723  0.158

PRL 89 (2002) 201802

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 k 0 s hep ex 0207070

sin2 - K0S hep-ex/0207070

  • Pure QCD Penguin, sensitive to New Physics contributions

  • In the SM, time-dependent asymmetry in K0S measures sin2b

B  K0S

51 events

From 87 M B pairs:

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 j 0 hep ex 0207058

If no penguins:

we measure -sin2b

+

407 events

sin2 - J/0 hep-ex/0207058

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 k 0 s

sin2 - ’K0S

B  ’K0S

203 events

Large Penguin contribution expected !

preliminary

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 d d b ccd

sin2 - D*D* (bccd)

hep-ex/0207072

  • D*+D*-, is not a CP eigenstate (L=0,2 and L=1)

  • CP odd fraction R 

  • .Transversity analysis

B0D*+ D*-

CP-odd fraction

R = 0.07  0.06  0.03

 mostly CP-even !

L.Lanceri - B-Factories: Physics Reach - CSNI


Sin2 d d

+

  • We measure :

    • Im(l+)

    • |l+|

-sin2b

Small ( < 0.1 T) penguin contribution expected

Im(l+) = 0.31  0.43 (stat)  0.13 (syst)

-sin2b = -0.741  0.067

|l+| = 0.98  0.25 (stat)  0.09 (syst)

From 126  12signal events

sin2 - D*D*

preliminary

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar sin2 b modes with penguins now

BaBar, sin2b: modes with Penguins, now

51 events

K0S

D*D*

126 12 events

+

J/0

407 events

’K0S

203 events

L.Lanceri - B-Factories: Physics Reach - CSNI


Babar present sin2 eff s pp and c pp

BaBar, present sin2eff: Spp and Cpp

PRL sub., hep-ex/0207055

B0 → p+ p -

L.Lanceri - B-Factories: Physics Reach - CSNI


Isospin analysis projections 21

BR(B`gp`p0) = 4.1x10-6

BR(B0gp+ p-) = BR(B0gp+ p-) = 4.7x10-6

Isospin analysis: projections - 2

  • Sensitivity to : toy MC with BaBar detector

  • Assumptions (example):

<BR(Bgp0p0)> = 1.0x10-6

L = 0.5 ab-1

L = 2.0 ab-1

4-fold ambiguity !





L.Lanceri - B-Factories: Physics Reach - CSNI


B factories physics reach

The theoretical error

of 10% should be further

reduced at the 5%

level using all

information

P*l, Q2 and Mx

L.Lanceri - B-Factories: Physics Reach - CSNI


Rare decays em penguins

Rare decays: EM Penguins

Fully inclusive b  s, lepton tag

SM expectation:

Exclusive b  d, from 78fb-1:

(interesting for |Vtd/Vts|2)

  • BF(B  )/BF(B  K*)

  •  |Vtd/Vts|2

Present analysis limited by

photons from Continuum bkgd:

without improvements:

3 sensitivity at 0.8 (0.25) ab-1

if bkgd x 0.5, then:

3 sensitivity at 0.4 (0.1) ab-1

for individual (combined) modes

L.Lanceri - B-Factories: Physics Reach - CSNI


  • Login