Risultati recenti di BaBar [Una selezione dalle conferenze estive] CSN1 Napoli 19/09/2005 Giuseppe...

Risultati recenti di BaBar[Una selezione dalle conferenze estive]

CSN1 Napoli 19/09/2005

Giuseppe FinocchiaroLaboratori Nazionali di Frascati

*ubudVV

*cbcdVV

*tbtdVV

19/09/2005 G. Finocchiaro @ CSN1 Napoli 2005 2

The gold rush

(Where `gold’ is no longer J/Ks)

Most analyses in this talk used the Run1-4 dataset (~240fb-1)

KEKB delivered ~470fb-1 so far

Run1

Run2

Run3

Run4

Run5


(The usual) disclaimer

Hard selection required in this talk (75 BABAR abstracts @LP05, 57 @EPS05) In spite of ‘sub-optimal’ PEP-II

performance this year so far, still competitive wrt Belle

“Di necessità virtù”: BABAR‘s analysis power generally (still) compensates for smaller integrated statistics

More physics channels Better detector (PID, vtx) More efficient analyses


Indice Angoli (I): , Lati (I): |Vub| da b→u ℓ sin2: (persistenti) indizi di NP Lati (II): |Vtd/Vts| da b→d/s Ancora nuovi stati: la Y(4260) Non parlerò di:

SM:

B→@CLSM:± B→Ks[hep-ex/0507038] SM:L.H. sin~

Conclusioni, prospettive

]%90@10[ )041802)2005(95(PRL)0508012/(

88.611 exhepe CL


UT angles: From direct CPV in the decay of charged B’s

Interfering tree amplitudes w/ CP-violating relative weak phase and CP-conserving relative strong phase

Interference if D0/D0 decay into identical final state CP-eigenstate decay: Gronau-London-Wyler (GLW) Doubly-Cabibbo-suppressed (DCS) decay: Atwood-Dunietz-

Soni (ADS) Dalitz plot analysis of 3-body decay, e.g., : Giri-

Grossman-Soffer-Zupan (GGSZ)

*cbcdVV

*ubudVV

00~SKD

b→ucsb→cus


It all depends on rB…

Sizable interference only if large enough amplitude ratio

Unfortunately, BABAR finds small rB

Error on vs. rB

rB≈ 30o error on w/ current BABAR data need to add more channels/data

2.01.0~)(

)(

cbA

ubArB

From CKM factors & color suppression


New GLW and ADS signals in][

~ 0*0 SKKDB

B+

B-

B-

B+

NCP+=37.6±7.4 NCP-=14.8±5.9

Right Sign Wrong Sign

WS B+ WS B-

mES (GeV/c²)

~90 events ~4 events

hep-ex/0508001CP-eigenstate decay DCS decay

D0→flavour non-CP

D0 CP+→K+K,

D0 CP-→KS0, KS, KS B

B

B

B

hep-ex/0507002, submitted to PRL


The idea in pictures:

CP-conjugate B and B decay amplitudes

is the same, r(*) and (*) depend on the mode

A(B)=|A(B→D0K)|×

m2

D0

+rBei(-+B)

D0

m2

m2

m2

GGSZ DP analysis of *)(][

~ 0(*)~

00(*)

KSDS KKKDB

),(),()( 2222

mmAeermmA||ABA Dii

BDBB

),(),()( 2222

mmAeermmA||ABA Dii

BDBB

(*)*(*)22(*)22 2|||||)(| BiiDDBDBD eeAArArABA

)( 022 SKmm

Assume D decays conserve CP…


DP analysis of D0/D0 decays

Extract D(bar) decay amplitudes from DP analysis of independent cc sample with flavor-tagged decays from

New K-matrix model: 9 BW resonances + K-matrix formalism for s-wave Deals with broad,

overlapping, multi-channel scalar resonances

00SKD 0* DD s

91fb-1 82k D0s

hep-ex/0507101

)( 022 SKmm


Signals in all modes (*)0(*)~KDB

D0K- D*0[D00]K- D*0[D0]K-~ ~ ~ ~ ~Mode

Signal events

B-D0K− 282 ± 20

90 ± 11

B-D*0[D0]K− 44 ± 8

B-D0K*−[K0S-] 42 ± 8

B-D*0[D00] K−

227×106 BB

~

~~

~~~

(mES>5.27 GeV/c²)

NEW B-D0K*−[KS]~

hep-ex/0507101

hep-ex/0

504039,

accepte

d by P

RL


GGSZ DP results: vs. r(*)B

Mode rB/r*B /rs

DK

D*K

DK*

statsystDP)o

all D()K() modes combined:

hep-ex/0507101

2 fold ambiguities for both and B

D0K- D*0K- D0K*-

rB

(d

eg

)

r*B .rs (<0.75@2 CL)

~ ~~

2 CL

1 CL

(stat.+syst. uncertainties)


Putting it all together…

… we can measure !!!! 3 theoretically clean (= w/o

penguins) methods to measure did not mention TD D(*)… (no new

measurement) Small r()

B very hard measurement, but no longer “mission impossible”

No single channel dominates To improve precision, need more

data/channels )(57 7

13-CKM )(63 1512-WA

BABAR only:: 231851


UT angles from TD asymmetries

d

d

0B

*tbV

tdV

b

b

0Bt

t

*tdV

tbV** // tdtbtdtb VVVVpq

B0B0 mixing

du

dd0B

/ubV

*udV

b /u

Tree decay

ubudVVA *

du

dd

0B

/g

b

/utcu ,,

Penguin decay

tbtdVVA *

Specific example is for , but valid in general Single CKM phase in decay ↔ Cf=0 (no direct CPV)

b→uud

Preamble: CPV from interference of decay and mixing

22

2

||1

Im2

||1

||1

SC

14

Difficult to reliably estimate how much penguins contribute

B(B0K+) (~ pure penguin) indicates they cannot be neglected

Gronau/London analysis Assuming isospin symmetry, these triangular relations between the Bhh amplitudes hold:

The B and B triangles do not match, and 2eff = 2+κ Need to measure 5 BFs, including B(B00) from tagged

samples still a 8-fold ambiguity

Grossman/Quinn bound:

and the penguins: more triangles are needed

effi

i

i

i eeT

P

eTP

eA

A

p

q

22 ||1

1

κ

000 22 AAAdecaysB

000 22 AAAdecaysB

)BF(B

)BF(Beff 0

00

2 )(sin


Measuring in B→ decays Tough analysis [VV state, , ’s are wide] However:

(~6 times x B→)

(isospin triangle collapses to a line) Small penguin contribution:

eff@CL

(almost pure CP-even state)

60 10)5430()( BB

CL %90 @ 101.1)( 6000 BB

021.0029.0014.0978.0

Lf

232M BB

PRL 95 041805 (2005)


from B→ decays

All three modes give consistent and complementary measurements of

constraint rather weak due to large penguin contamination

yields single most precise constraint

TD analysis of Dalitz plot in Weak constraint at 90% CL, but disfavors mirror solution near 170o

)99][ 129-hh (

)(95 1013-CKM


UT sides: |Vub|Tree-level process (charmless semileptonic) NP free ‘complementary’ (opposite in the UT) to sin

BF(b→u l ) measured from inclusive and exclusive s.l. branching fractions From inclusive (partial) s.l. BFs using O.P.E.

reliable prediction of total B→Xuℓ decay rate experiment measures partial BFs (hard cuts against B→Xcℓ) biggest uncertainty in extrapolation of BF(b→u l ) to full phase space from

motion of b quark in B meson Parameters measured e.g. from E* in b→s

VcdVcb*

VudVub* VtdVtb

*

γ

α

β

PRD72 052004 (2005)


Inclusive |Vub| measurements

Electron endpoint spectrum

Electron and momentum

Lepton and hadronic system recoiling against fully-reconstructed B mesons

signalregion sideban

dregion

signal

88M BB

hep-ex/0408075, being submitted to PRD

3th

42.0

38.0exp 10)22.025.044.4(||

SFubV

lEq 2

89M BB

hep-ex/0506036 submitted to PRL

3th

58.0

42.0exp 10)25.026.095.3(||

HQubV

232M BB

hep-ex/0507017

3th

46.0

38.0exp 10)23.034.065.4(||

SFubV

Xmq 2

19

|Vub| from exclusive measurements: untagged Bℓ

Exclusive s.l. BFs |Vub| using form factors (FFs) in bins of q2

several approaches LCSRs, LQCD, quark models … FF uncertainties affect measurement twice

1. FF shape acceptance try and measure on data2. FF normalisation in extraction of |Vub| from pBF (~10-15%)

|Vub|=(3.82±0.14stat±0.22syst±0.11FF– 0.52FFnorm)x10-3+0.88

83M BB, hep-ex/0507003, subm. to PRD

LCSR LQCD

)/(|| 0 Bub BV

for GeV


Incl. vs. Excl. : which wins?Inclusive

Improved expt. error: 4% Very much improved theory

error ( OPE parameters): 6%

Exclusive Improved expt. error: 4% Theory error still dominant: ≥15%

Experimental input, i.e., FF shape, will reduce theory error in the future

Measurements now compatible within errors

325.022.0 10)56.3(

CKM

ubV

Indirect |Vub| determination

]HFAG[10)16.076.3(|| 387.0

51.0exp

LQCDubV

]HFAG[10)27.019.038.4(|| 3th,exp

bmubV


Why this is relevant

• constraints from TREE process only

• Gauge the UT in any extension of the SM

• Firm starting point for NP searches

UTfit JHEP 0507:028,2005


sin2 from charmonium [to find NP, must know OP]

Reference point for NP C=0 (only 1 phase) S=-fsin

Precise! Validation of SM predictions

sin[UTFit]=0.793±0.033 (sides) [0.734±0.024 (all)] In fact, a big success…

J/

KS

BO

032.0687.02sin EPS'05 New Belle meas. (357M BB):sin0.652±0.044


Why b→s penguins are good for NP

Small effects (e.g. from propagators of heavy particles circulating in the loop) more easily detectable since Tree is missing

CKM factors same as J/Ks

If single phase, SM predicts: Speng=Scharmonium=sin Cpeng=Ccharmonium

Naïve [HFAG] average of penguin modes 2.7 below charmonium

note: BABAR and Bellehave ~same precision


To find NP, must know OP (II)

In fact, we know that > 1 amplitude/phase is (usually) involved

e.g., b→uus CS tree () in channels involving non-strange neutral mesons

Even J/Ks could have penguins S± [hep-ph/0507290]

Is there a dominant one? Intense theoretical work lately

sin always >0 (contrary to experiment)

some predictions quite precise theory parameters constrained to

measured BF (will further improve) Averaging still not meaningful

QC

D f

act

oriz

atio

n:

[Ch

en

g,C

hu

a,S

on

i, h

ep

-ph

/05

06

26

8]

[Be

ne

ke,

he

p-p

h/0

50

50

75

]

sin


New signals (~230M BB) in [KK]KL0

hep-e

x/0

50

70

87

KS0

has smallest stat. error on sin KL

0 adds 50% more events ( total)

SK0 ±±, CK0 ±±

K0 and KKK0 have largest BF

among b→s modes

SK+KK0L ±±, CK+KK0

L ±±Using fCP-even ±±

sinK+KK0 ±±±

hep-ex/0507016


CPV in b→s penguins Intriguing difference from b→c remains

This could be one of the greatest discoveries of the century, depending, of course, on how far down it goes…

2.7


b→d Large background Only accessible through exclusive modes B Simultaneous fit to B+→, B0→, B+→ assuming

BBM 211

hep-ex/0408034

2.1/

0.1

4.0

8.1

)BF(10Channel

0

-6

Belle claim observation


UT sides: |Vtd/Vts| Constraint used to come entirely from md/ms

(smaller theoretical uncertainty on ) Now radiative penguins sufficiently precise to start providing

meaningful UT constraints, using:

Low B→ BF favors small |Vtd|

VcdVcb*

VudVub* VtdVtb

*

γ

α

β

ssdd BfBf 22 /

s

dd m

mm

and

)(

)(*

KBB

BB

R=0 in this plot

Ali et al.,Eur.Phys.J.C23:89-112,2002

FF ratio ±

difference in dynamics R


New States: X→J/ Discovered by Belle in 2003 in

3872 is just above open-charm threshold Confirmed by D0, CDF, BABAR

isovector charged partner(s) must exist ruled out @10CL by BABAR in B0(+)→XK

searched in B0(+)→X0(J/)K decays

Need more data to discriminate among different models Does not fit in standard charmonium spectroscopy

why does not decay onto DD? J/ isospin violating (but is a ?)

[qq][qq] [Maiani et al. PRD71, 014028 (2005)]: R=1, m±MeV/c2

D*0D0 molecule [PRD71, 074005 (2005)]: R<0.1 Search in ISR events

J)3872( ,)3872( XKXB 6.1σ

2.5 σ

R=BF(B0→XKS)/BF(B→XK)=

m= MeV/c2

JPC= 1(2S),

(3770), …

...no sign of X(3872) in ISR, but...

Discover Y(4260)→J/!!

S

hep-ex/0506081

232fb-1

Just above DSDS threshold Could be two states

Very robust signal. Among other tests: Use (2S) for optimisation/validation fit for null signal with

different bkgd shapes bin sizes

check for reflections

Split by run, J/ decay mode search in J/sidebands require ISR (25% of events) change/reverse selection feed-down e.g. from undetected 0

Peak cross section ~50pb


Where else?

No trace in R-scan hadnb Y~pb accuracy of R~4%

no surprise it‘s not seen in R

• But why a dip?• And why does not decay to DD?

Y(4260)

√s (GeV)

Feeble signal (so far) inB→J/K

• 3.1 assuming mISR, wISR • need more data


Summary & outlook

CPV in mixing↔decay (and decay) well established Precision in measurements of CKM parameters steadily improving The Standard Model resists (surprisingly well…)

New states keep popping up in unexpected places renewed interest in spectroscopy, new models proposed and being scrutinized

Finding NP is the name of the game now Deviations from sin in b→s penguin getting smaller (~1 for most modes) In general, processes with clear SM predictions are good candidates

B→around the corner?

20052005 2008 (?)2008 (?)


The next few years

Statistical uncertainties have scaled so far faster than (adding new channels) Even for J/Ks systematics not an issue, for several ab yet Theory often feeded by exptl. measurements

also improves with more data Expected precision on UT angles vs. time:

L/1

from

sin in penguins

from B→DK


Our analysis commitments

BaBar in Italia

Torino: decadimenti senzacharm a due corpi (, K,KK), Vub (recoil)

Milano: analisi dipendenti dal tempo in decadimenti senza charm e misure di BF (KKS/LaK/Ks)

Genova: charmonio(B cc adroni,B cc[Cg]K),

Pisa: sin/CP/CPT, vita media del , →Ks, DK Dalitz per l'estrazione di b→s inclusivo, B→D*l , B→D0

CPK(), B→D*

Roma I: sin(), BDS/K, DKS, b→s sul rinculo, mixing del B, X(3872), Vub, DK Dalitz per l'estrazione di , decadimenti senza charm e analisi dipendenti dal tempo per l'estrazione di (K, KK), →, sin dai pinguini (KS, KL, KSKSKS ,K+KKL,KS, K*), B→K+

Trieste: B→D*D*, Vcb B→D*l BD(*)DsJ

Padova: Vcb B→D*l Vub, vitamedia e mixing del B, →CPV nel mixing

Ferrara: Vub, Vcb e charmonio sul rinculo

Perugia: BD*DS*, DS,

, CPV dal lato di tag,CPV nel mixing

LN Frascati: BD*D*, BD*DS*,

DS, ISRK*+K, ISRCPV nel mixing

Napoli: Vcb B→D*l B→J/KB→ decadimenti semileptonici

Bari: decadimenti a 3 corpi della D,DsJ*(2317)+, DsJ*(2460)+ (analisi di Dalitz)

°o

° ° °

°

°°

°°

°°


Backup slides


L-scaling of channels for angles measurements


How NP would be constrained

NP (assuming only in loops) parameterised as di

ddeCSM

NPSM

From tree measurements


Event yields in 229M BBbar

soon to come: forward-backward asymmetry

RK = 1.06 0.48 0.05 [SM:~1]RK*= 0.93 0.46 0.12 [SM:~0.75]

ACP(K) [SM:~0]ACP(K*) [SM:~0]

ll(*)KB

hep-ex/0507005, preliminary

N=57±14

ll*KB

N=45±10

llKB smallest BF fromB’s measured to date!

• sensitive to relative contribution of -, Z-penguin and box diagram• new physics can show up in any of these


B→Ks Phase in B→K*0 between mixed and

unmixed decay is 2 W couples only to left-handed quark: b→sL

interference suppressed in SM: Smix -2ms/mb sin sin

possibly large enhancement from NP can use Ks0 even if not from resonance (Atwood

et al (2004))

2.00.19.0)(05.040.021.0)(

00

0*

SKSKSK

non-K

Compatible w/ SMErrors still large

hep-ex/0507038, submitted to PRL232M BB


B→ CKM fit predicts

Direct measurement of fB (currently only from LQCD)

B→/md constraints |Vub/Vtd|

> 2 in the event. Analysis:o Use hadronic or semileptonic tago 1 or 3 prong topology

o Can constrain SUSY parameters

510)5.21.8()Β( B

C.L.%[email protected] 4)Β( B

BBM 232 We’re almost there!


(NP in) b→d/s

• FCNC• sensitive to NP @ EW scale• solid SM predictions:

• BFB→Xs

• ACP~0• Huge backgrounds

• cuts on or Xs spectra ↔ model dependence

• Fully inclusive (no requirement on Xs/d)• lepton tag [/1200 on Bkg (/20 on Sig)]• topology cuts, vetoes

• Exclusive (semi-inclusive) b→s• reconstruct Xs→K+n+m (n,m<5)

• 38 states,55% of all possible 1504 85sigN


b→d/s spectra, BF, ACP

Inclusive Semi-inclusive

ACP(b s b d ) = ( 0.010 0.115 0.017 )

hep-ex/0506043

BBM 88

BBM 153 hep-ex/0403004

Partial Branching Fractions (PBF)

(4s) frame B rest frame

LP Paper-100

Method, cut BF(10-4)

Inclusive, 1.9 GeV

Exclusive, 1.6 GeV

Inclusive, 1.8 GeV

29.034.029.067.3

07.064.008.041.019.038.3

11.030.007.031.032.055.3


from B[K]K: ADS method

Equalize the interfering amplitudes (PRL 78, 3257)

Extract from decay rates measurements

KKB D][ KDKDB 00 ,

favored suppressed

KDKDB 00 ,favoredsuppressed

coscos2

)][()][(

)][()][(22

sup.

fav.

favoured

suppressed

BDBDK rrrrN

N

KKBKKB

KKBKKBR

0.93±0.04

rD=0.060±0.003, from

D*+[K± ]

rB~0.1÷0.3

Risultati recenti di BaBar [Una selezione dalle conferenze estive] CSN1 Napoli 19/09/2005 Giuseppe...

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Transcript of Risultati recenti di BaBar [Una selezione dalle conferenze estive] CSN1 Napoli 19/09/2005 Giuseppe...