Transcript Physics with BaBar 1999

An overview of
BaBar physics & prospects
Hassan Jawahery
University of Maryland
SLUO meeting of Sept 11. 2006
1#
Outline
• A few comments on the status of the experiment.
• A brief overview of impact of BaBar physics & the
physics harvest of summer 2006
• Outlook for the 1/ab phase.
• The best and freshest results to be presented by
Denis Dujmic later at this meeting and David
Lange in his SLAC seminar on Wednesday.
2#
The B factory: PEP II Machine & BaBar Detector
Operating at the
U(4s) resonance
3#
USA
[38/311]
INFN,
INFN,
INFN,
INFN,
The BABAR
Collaboration
California Institute of Technology
UC, Irvine
UC, Los Angeles
UC, Riverside
UC, San Diego
UC, Santa Barbara
UC, Santa Cruz
U of Cincinnati
U of Colorado
Stanford U
Colorado State
U of Tennessee
Harvard U
U of Texas at Austin
U of Iowa
U of Texas at Dallas
Iowa State U
Vanderbilt
LBNL
U of Wisconsin
LLNL
Yale
U of Louisville
U of Maryland
[4/24]
U of Massachusetts, Amherst Canada
MIT
U of British Columbia
U of Mississippi
McGill U
Mount Holyoke College
U de Montréal
SUNY, Albany
U of Victoria
U of Notre Dame
Ohio State U
China
[1/5]
U of Oregon
Inst. of High Energy Physics, Beijing
U of Pennsylvania
Prairie View A&M U
France
[5/53]
Princeton U
LAPP, Annecy
SLAC
LAL Orsay
U of South Carolina
11 Countries
80 Institutions
623 Physicists
The Netherlands [1/4]
NIKHEF, Amsterdam
Norway
[5/24]
Ruhr U Bochum
U Dortmund
Technische U Dresden
U Heidelberg
U Rostock
Italy
[1/3]
U of Bergen
LPNHE des Universités Paris
VI et VII
Ecole Polytechnique, Laboratoire
Leprince-Ringuet
CEA, DAPNIA, CE-Saclay
Germany
Perugia & Univ
Roma & Univ "La Sapienza"
Torino & Univ
Trieste & Univ
[12/99]
INFN, Bari
INFN, Ferrara
Lab. Nazionali di Frascati dell' INFN
INFN, Genova & Univ
INFN, Milano & Univ
INFN, Napoli & Univ
INFN, Padova & Univ
INFN, Pisa & Univ & Scuola
Normale Superiore
Russia
[1/13]
Spain
[2/3]
Budker Institute, Novosibirsk
IFAE-Barcelona
IFIC-Valencia
United Kingdom
[11/75]
U of Birmingham
U of Bristol
Brunel U
U of Edinburgh
U of Liverpool
Imperial College
Queen Mary , U of London
U of London, Royal Holloway
U of Manchester
Rutherford Appleton Laboratory
U of Warwick
4#
End of the eventful Run 5- August 21
PEP II Reached 12.0x 1033 /cm2 /s
A heroic achievement.
Congratulations to the PEP II team!
BaBar collects
~96% of PEP II
delivery
5#
•
6#
BaBar Data: Runs 1-5
Partial composition of the
data
9
~ 0.4 x10 BB
9
~ 0.5 x10 cc
~ 0.4 x109 
&

e  e  qq
-
ISR
7#
Onward to the 1/ab data phase 2006-2008
• Shutdown Aug 21 through Dec. 06 PEP II Upgrade: Major upgrade to the machine to take the
peak luminosity from 12x1033 /cm2/s  20 x1033 /cm2/s
(list from John Seeman)
 BaBar:
 Completing the upgrade of the Instrumented Flux Return (IFR)replace RPC’s with LST’s in the remaining 4 sectors (2 sectors were
done in 2002). Expect to fully recover (the slowly deteriorating) muon
and KL identification capabilities of the detector.
 Preparing for the expected higher data rate (and possibly higher
background). Aims to stay at its usual very high efficiency of data
collection (~96% historical average). Now studying the trigger and
data flow system for possible bottlenecks and preparing for solutions.
Now in the third week of the shutdown and on schedule.
8#
Future PEP-II Overall Parameters
A page from
and
Goals
John Seeman
Parameter
Units
Design
Present best
2007 goal
I+
mA
2140
2900
4000
I-
mA
750
1875
2200
1658
1722
1732
Number
bunches
by*
mm
15-20
10
8-8.5
Bunch length
mm
15
11-12
8.5-9
0.03
0.05-0.07
0.06-0.075
xy
Luminosity
x1033
3
12.1
20
Int lumin in
24 hours
pb-1
130
911
1300
4 times design
7 times design
9#
Onward to the 1/ab Phase of BaBar 2006-2008
•
Another page from John Seeman
Goal = 940 fb-1
2007
Down
2006
Down
Now
10#
The physics reach of the BaBar Data
Just about any physics that is
accessible at
s  10
GeV
CP Studies with B’s
& B Physics
Charm Physics
Tau physics
Continuum e+e- hadrons
ISR: e+e- hadrons from threshold to ~5 GeV
11#
Physics Harvest of summer 2006
Runs 1-5
Submitted 114 papers to the ICHEP 2006 in Moscow
http://www-public.slac.stanford.edu/babar/ICHEP06_papers_temp.htm
Measurements related to alpha (5 )
Measurements related to beta (14)
Measurements related to gamma (8)
Charmless B Decays (18)
B decays to open Charm (12)
Semileptonic B decays (10)
Radiative Penguin and Leptonic B decays (10)
Charmonium and Charm Spectroscopy (16)
Production and decay of Charm and Charmonium states (13)
Tau and low energy physics (8)
&
26 Invited Talks
[Some excerpts here]
12#
The physics reach of the BaBar Data:charm
Charm physics with ~ 0.4 x109 cc
 Search for D0 mixing – highly suppressed in SM- a powerful window
for NP searches
The Latest
Observables:
from BaBar
CP even state: width G , mass m ;
1
1
CP odd state: width G2 , mass m2
y = (G1 - G2) / (G1  G2) = DG / 2G
x = (m1 – m2) / G = Dm / G
D0 Mixing Still consistent with zero. Limits approaching the SM expectation
13#
The physics reach of the BaBar Data: charm
More Charm physics with ~ 0.4 x109 cc
 Charm Spectroscopy: Keep finding New Charm Meson and Baryon states-
Wc
*
Wc
0g
Our latest: Observation of a
new excited charm baryon
W c*  W c0 g
Wait for David Lange’s
seminar for details
 Testing ground for Lattice QCD: Measurements of decay constants fD, fDs, fD/ fDs &
Form Factors are now emerging
489  55 signal
= By validating LQCD, we may hope
FDs=248+/-15+/-6+/for better knowledge of fB & (BB?)
31 MeV
, hence better knowledge of
|Vub|, |Vtd|, |Vts| & |Vtd|/ Vts|
Dm = m( g )  m(  )
 Many engineering results of importance to B decays: e.g. measuring the phase and
amplitude across several 3-body D meson Dalitz plots is critical for measuring
angles g & b with B decays.
14#
The physics reach of the BaBar data:  decays
B factory data the primary source for searches for Lepton Flavor
Violation (LFV) in  decays: Recent results on:
g & eg  h & (Lepton and Flavor Violating decays) Lh
highly suppressed in SM; (see David Lange’s talk for new BaBar results)
From Roger Barlow’s talk at
ICHEP06
Limits on Branching ratios: @90% C.L
BaBar: Br(g)<0.68x10-7
Example of how it impacts
BaBar result
Br(eg)<1.1x10-7
Belle: Br(g)<0.41x10-7
Br(eg)<1.2x10-7
Belle result
15#
The physics reach of the BaBa: ISR
Hadron
Provides access to e+e- from
threshold to ~5 GeV
Allows for determination of R,
which goes into calculation of
muon g-2. So far has Measured:
.e+e  pp, ppp, 2p2p, K+K-pp, 2K+2K-, 3p3p, 2p2pp0p0,
K+K-2p2p, K+Kpp, K+Kp0p0 , pp, f0(80)
Showing new
structure
• Discovery of New States- Y(4260), and further investigation of new states
(2S)
This year’s new structure
N=125±23
(>8 σ)
16#
The physics reach of the BaBar Data: B Decays
B Physics [with the ~ 0.4 x109 BB ]
 Investigation of CP violation in B meson Decays & tests of
the CKM paradigm
 Is the CP symmetry broken in B decays?
 Can we fit the CPV effects in the CKM picture?
Is there room for New Physics?
 Search for New Physics in rare (SM suppressed-FCNC)
decays ?
 B Decays dynamics: Tests of QCD predictions
17#
A brief history of major milestones in B physics
109--
108--
107-#B’s
The 1/ab phase: Precision tests of the CKM
paradigm- Search for N.P. using loop dominated B
decays, LFV tau decays, DD(bar) mixing …
Precision sin2b; a & g measured; CKM overconstrained and established as the primary source of
observed CPV in nature. Data consistent with no NP
effects in b-d and sd.
2001- CPV in B decays observed.
Sin2b consistent with SM
1999- B Factories start operation.
106--
1993-Radiative penguin bsg observed; Major constraint
on models of New Physics;Rare decays BKp and pp
obserevd; Role of gluonic penguins established;
B factory projects launched.
105--
104--
1987-B0 mixing & Vub measured;
Lower bound on m(top)>42 GeV;
with non-zero Vub, CKM in the
game as a source of CPV
1981-B meson observed
18#
The Latest on the CKM test:
Theorist view of CKM
Observables
The view from the experiments
a
g
Picture from A. Hoecker
19#
From
J. Charles
@
FPCP 2006
Vancouver,
Ca
Check for
New Physics
contribution
Back
20#
Any room for New Physics contributions?
The analysis by the UTfit collab. allows NP amplitude and phase: [ Hep-ph/0509219]
( DMBd ) = CBd ( DMBd
)
SM
ACP (J / KS ) = sin2 ( b  Bd
0
SM solution
)
CBd=1 & Bd=0
Non –SM solution is now essentially excluded. Limits
on Semileptonic asymmetry (Asl) from BaBar & D0
21#
 The message from New Physics Fits to CKM observables (As
presented at LP2005- by L. Silvestrini) –
 New sources of CP violation in bd & sd are strongly constrained.
 New Physics contributions to the bs transitions are much less
constrained & are in fact well motivated by models explaining large
mixing angles in neutrino sectord
gL
W
sL
bR
bL
tL
W
b
u,c , t
g
d
Possible New Physics presence can alter
the observables from SM expecations
s
s
s
22#
The “sin2bpenguin” Test:
Mixing induced CP violation in penguin modes b->sqq
B0
fcp
G( B 0 (t )  fcp)  G( B 0 (t )  fcp)
Acp(t ) =
= S sin Dmt  C cosDmt
0
0
G( B (t )  fcp)  G( B (t )  fcp)
B0
For fcp =from b->sqq
W
b
B0
d
u,c , t
g
Within the SM:
A = VcbVcs* [Pc  Pt  Tc ] VubVus* [Pu  Pt  Tu ]
s  ,h ,( KK )
CP
s
s
Dominant amplitudef
(~l2) same phase
as b->ccs
suppressed
amplitude (~l4)
K S0
Expect
Sf~ -hcpsin2b
within SM
With new physics and new phases, Sf could depart from -hcpsin2b
The Task: Measure DSf=-hcpSf – sin2b & search for deviation from zero
A Key Question: How well do we know DSf within the SM?
23#
Expected DS with SM
More details in Denis Dujmic’s talk
Simple average: Spenguins=0.52 +/- 0.05 vs reference point: sin2b=0.68+/-0.03
~ 2.5 s deviation at this point.
Eagerly waiting for more data
24#
bsg & bsl+l-  well established venues for NP searches
gL
W
sL
bR
bL
tL
Measured rates consistent with SM:
BF(b→sg)TH = 3.57 ± 0.30 x 10-4 (SM NLO)
BF(b→sg)EXP = 3.55 ± 0.26 x 10-4 (HFAG)
D0
•Direct CP violation – nearly zero in SM
b-d g is now also
established by BaBar
& Belle
•In BKll- q2 dependence of the rate; FB asymmetry, polariztion
BaBar’s limit on Bpll
But there is more handles in these channels
•Photon polarization in bgsL (g left-handed in SM)
Search for NP modification of Wilson coefficients C7, C9, C10
25#
Tests with bsl+l-
[BK l l
*+-
Probe deviation of wilson coefficients., C7, C9, C10
from SM
]
FT = 1 – F0
Zero point of AFB a probe of NP
influence
K* pol. FL
C7 = -C7(SM)
Wrong sign C9C10 excluded
Cannot exclude opposite sign C7 yet
C9C10 = -C9C10(SM)
26#
• Tests with Direct CP violations
Direct CP violation results when several diagrams, with different
cp conserving and cp breaking phases contributing to the same
final state, interfere:
 
0 
0 0
E.g. BKp: BKp: (K p , K p , K p , ..)
u
b
W
u
+
t
d, s
iγ
A = (|T|e  |P|eiδ )
A = (|T|e
 iγ
W
b
g
d, s
u
u
 |P|eiδ )
Γ( Β f)  Γ( Βf)
P
Acp = Γ( Βf) Γ( Β f) =2| T | sin δ sin γ
A contributing diagram from “New Physics” can alter Acp from the SM
values. But need predictions of Acp within SM- Again rely on QCDF or
PQCD, or exploit symmetries (SU2, SU3 etc) to connect A cp in different
modes and derive sum rules- to be tested.
27#
Within SM: Expect Acp(b->sg) ~ 0
Acp
(B0Kp)=
0.099+/- 0.016
Another potential source of tension with SM
Kp puzzle
superweak is really out; to use as NP observable need reliable QCD
predictions; Ample data to test & calibrate the calculations on.
28#
Prospects for the CKM observables in
the “1/ab” phase
(~ +1/ab from Belle)
Aiming for:
s ( Vub |)  5%
Now
~7%
s (g )  5  10o
~30O
s (a )  8o
s (sin 2 b ) = 0.02
~11o
Also counting on
improved systematics in
most areas & help from
the theory side
~0.04
& s(Vtd/Vts)<4% (mostly from Tevatron).
29#
Summary comments
 There is an enormous amount of physics still to come from
Flavor physics with BaBar in its “1/ab” phase. Two of the
expected major outcomes are:
 Precision knowledge of the charge weak sector of the SM &
CKM parameters,
With the possibility of revealing deviation from the SM
 Measurements of CP violation and decay properties in penguin
dominated decay modes, with the possibility of revealing New
Physics effects. Hints are already present in the current data.
[Given the large number of observables involved, a pattern may
emerge showing evidence for New Physics. If we continue to see
no deviation at these precisions- the results will likely serve as
major constraints on the flavor structure of New Physics- to be
seen at LHC.]
 PEP II and BaBar are in preparation for the “1/ab” phase.
30#
Both upgrade efforts are proceeding well and on schedule.
Back up Slides
On
Prospects for CKM Observables
31#
Measuring Vub= |Vub|e-ig
Higher precision on knowledge of Vub is absolutely
essential- one of the main sources of tension in CKM tests
sin2b =0.791±0.034
from indirect determination
sin2b=0.687±0.032
From direct measurement
32#
Inclusive channels
Exclusive channels
~7% measurement now
~20% now. Not a useful cross check
for the inclusive approach- yet.
Aiming for 5% accuracy
Must resolve exclusive & inclusive
discrepancy
33#
Measuring g: Vub= |Vub|e-ig
Decays involving interference of tree level bu & bc Processes.
b
b
u
W
+
W
c
s
B   D 0K 
B-  (Df)KF=common to D0 & anti D0
c
u
s
B   D0 K 
A[ B   ( D  f ) K  ]  1  rBei (d g )
A[ B   ( D  f ) K  ]  1 r B ei (d g )
Solve for g, & d=(,d1d2) –
rB=(|A1|/ |A2|)
f=DCP (Gronau-London-Wyler)(GLW method) (small asymmetry)
f=DCSD (Atwood-Duniets-Soni)(ADS Method) (additional problem of dD)
f= Dalitz analysis of D0->Kspp (GGSZ) (combines features of GLW &
ADS depending on the location in Dalitz plot)- the dominant method
[Giri, Grossman, Soffer, & Zupan, PRD 68, 054018 (2003),
Bondar (Belle), PRD 70, 072003 (2004)]
34#
Measuring g: Vub= |Vub|e-ig
From the Dalitz Analysis alone:
The method highly sensitive to rB:
fits favor rB ~ 0.1 (BaBar) ; rB >0.2 (Belle).
Main cause of the difference in errors
g=(92+/- 41
 11 +/- 12 )o (BaBar)
φ3=53° +15-18  3° 9°) Belle
Combined (UTfit): g = 78 +/- 30o
All methods
Error due to uncertainties in treatment of the DKsppDalitz plot (amplitudes and phases)
-CLEO-c data can help. Projected error 3-5 deg (@1/ab
Future of g
rB=0.1
2008: 5-10o
Requires improvement in D-Dalitz model
– from CLEO-c data and higher statistics
tagged D* events at B factories
35#
Measuring a: The prescription
b
W
u
Bp p: (p p, p p0, p0 p0 )
u
Brp, B r r, …..
d, s
With Tree alone
But penguins (gluonic & E.W) can
also lead to the same decays:
W
b
t
g
d, s
u
Vtb*VtdVubVud*
i 2a
l =h
=
e
VtbVtd*Vub* Vud
C =0
&
S = sin(2a )
P iδ iγ
|e e
2i
a
T
λ=e
P
 iγ
1 | | e iδ e
T
C0
& S = 1  C 2 sin( 2 α )
eff
1 |
u
Estimate Da by constructing
the isospin triangle(Gronau &
London)
1
A(B 0  π  π  )
2
 ππ
Da
A(B0  π0 π0 )
1 ~ 0
A(B  π  π  )
2
~
A(B  π π0 ) = A(B  π π0 )
~
A(B 0  π0 π0 )
B->p0p0 sets
the scale of
the Da
correction
36#
B(p+p0) = (5.75 0.42)
B(p+p-) = (5.20 0.25)  10-6
B(p0p0) = (1.30 0.21)
A(p0p0) = +0.35 0.33
S(p+p-) = 0.59  0.09
A=-C
A(p+p-) = +0.39  0.07
Measuring a
Br(Brr)=23.5/ 2.2/ 4.1x10-6
Br(Brr0)=16.8+/- 2.2+/- 2.3x10-6
Br(Br0r0)=1.16+/- 0.37+/- 0.27x10-6
S=-0.19 +/- 0.21 +0.05-0.07
C=-0.07 +/- 0.15+/- 0.06
0
0 0
B
(
B

p
p )
2
sin Da 
B ( B   p p 0 )
Longitudenal polarization fraction
dominate (~90%)
Good news for a: A very lucky angle!
==| Da < 40o (90% c.l.)
Longitudinal polarization dominates-CP even &
small B->r0r0 compared to B->rr0 , B->rr 
suppressed penguin contributions-
sin (a eff  a )  ( f
2
r 0r 0
L
B
r 0r 0
) /( f
r r0
L
B
r r0
)
==| a eff  a |< 21o
37#
Measuring a
BaBar: a [86,114]
a = 9311
9
at 68% c.l.
(Brr, pp, rp) (WA)
Already the error is systematic (theory)
dominated.
At ~2/ab, expect s(a) ~ 7o  10o
depending on the size of B->r0r0 .
Measuring B->r0r0 & its Time-dependent
CP asymmetry will shrink errors further.
Other ways of estimating
penguin effects
38#
Measuring sin2b:
G( B 0 (t )  fcp)  G( B 0 (t )  fcp)
Acp(t ) =
= S sin Dm t  C cos Dm t
0
0
G( B (t )  fcp)  G( B (t )  fcp)
S = sin 2b ( for fcp = ccs modes) ; C = direct CP violation
(cc )KS0 +
(cc )K L0
Sin2b is a precision measurement now - the non-SM
solution is essentially excluded B->J/K* & B->D0h
No evidence for direct CP violation- consistent with
dominance of one diagram only-
At 2/ab (together with
Belle):
Expect another factor
of 2 reduction of
errors
39#