New results from BaBar

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New results from BaBar

• Fernando Ferroni
• Universita La Sapienza and INFN Roma
• Clermont Ferrand 29/04/2005

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Outline

• BaBar at PePII
• The 3 most precious gems of the collection
• CP violation in B-physics
• Recent results
• Perspectives
• Conclusions

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BaBar at PEPII
Excellent S/B Lorentz boost forward High
Luminosity
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BaBar
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The nicest of the BaBar sub-detectors
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Data Sample
244 fb-1 Run1-4 data
Luminosity 0.92 1034 cm-2s-1 Not running since
July 2004 due to a summer shut-down and an
accident occurred when restarting Restarting
now. Plan to run continuosly till next summer
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The 3 gems of the collection

• The precision measurement of ?
• The discovery of direct CP violation in B-physics
• The renaissance of hadron spectroscopy the
  DsJ(2317)

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The measurement of sin2?
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Direct CP violation
40 years for the K 4 years for the B
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New hadron spectroscopy
Remnant of a huge D peak chopped by phase space
DsJ(2317)
The threshold behaviour
DsJ(2317)
Ds?0
?
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CP violation in Standard Model
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CP violation in CKM
CP violation proportional to triangle
area Measure angles and sides Either ? or New
Physics
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The B triangle
with one caveat (at 10-11 level)
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Primers
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Time dependent CP analyses

• Consider B decays to a mode f
• interference between mixing and decay

decay amplitude phase
mixing
decay
mixing phase
f is not necessarily a CP eigenstate
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The paradigma
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Physics on the recoil
The high luminosity and the high number of fully
reconstructed Bs opens a brand new world in B
physics Fully reconstruct one of the B and study
the remaining of the event close kinematics,
missing energy reconstruction
Tag types
Semileptonic D()l(np) 5K/fb-1 Hadronic
D() X 3K/fb-1
purity
efficiency
Xnpmp0pKqKs
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Time dependent CP technique
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The Breco(nstruction)
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The recent additionto the collection
B?rr
ALL PRELIMINARY
a
Vub, b?sg
g
b
wKs,KsKsKs
Dp, D0K,

• new physics studies
• t?mg
• X(3872)

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Measurements of b
a
g
b
wKs,KsKsKs

• New physics and penguins

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Penguins and new physics

• Golden-tree and penguin modes

Tree
SJ/yKs SfKs sin2b CJ/yKs CfKs 0
In SM lJ/yKs lfKs
Penguin
In general case of New Physics
SJ/yKs ? SfKs CJ/yKs ? CfKs
W New Physics?
lJ/yKs ? lfKs
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Not so easy

• Precise (?) SM prediction
• fKs,KsKsKs
• Unknown Tree Pollution
• f0Ks,hKs
• Large (?) Tree Pollution
• wKs,Ksp0

w
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A three body mode KSKSKS

• Although 3-body decay, only Leven partial
  waves allowed CP of final state known
• CP(KSKSKS) CP(KS) even
• KSKSKS is theoretically as clean as fKS, with
  similar statistical power.
• This is valid for any P0P0P0 decay

Gershon, Hazumi hep-ph/0402097
88 10 signal events
PRELIMINARY

• No charged-track from B-vertex use
  IP-constrained vertexing

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IP-ConstrainedVertexing
Same technique as Ksp0 hep-ex/0503011
Constrain decay products to beam-spot in x-y

• Vertex precision depends on number of hits in
  SVT
• For 4 hits, ?t resolution as good as with
  charged-tracks (60 events)
• Crosscheck with J/yKS compare IP-constrained
  (Ksignore J/y) and nominal (J/y) vertex

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sin2b from KSKSKS
hep-ex/0502013
PRELIMINARY
BABAR
SM
227M BB
Belle BELLE-CONF-0475
275M BB

• Systematic errors dominated by
• PDF modeling, ?t resolution
• Vertexing method, SVT alignment

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wKs results
PRELIMINARY
PRELIMINARY
SM, only penguins S0.73 C0
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Summary of sin2ß from b?s penguins
Overall good agreement between the two
experiments Systematically lower than Charmonium
modes
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b?s penguins and SM
Deviation from SM No theory error 3.7
s Naïve theory errors 2.9 s
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Measurements of a
B?rr
a
g
b
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sin2? from rr - method
To disentangle the Penguin contribution (unknown
P/T and relative phase d) isospin analysis,
requires measuring Amplitudes for B0?rr-,
B0?rr-, B?rr0, B0?r0r0, and B0?r0r0 (Gronau
London)
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B??? measuring a

• 4-body (r?pp) final states with two vector
  intermediate states
• 4-body amplitude analysis
• replaced by quasi-two-body approach
• Interferences and higher resonances studied in
  detail and found to be negligible
• Angular and time dependent analysis
• Isospin analysis to get a

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??- angular analysis

• Only one amplitude seems to contribute

PRELIMINARY
signal
bkgd
Approximation set CT0 and ST0
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??- isospin analysis

• Assume only iso-spin conserving strong
  interactions
• EW penguins estimated to be 2o CKMFitter,
  using Buras, Fleisher EPJ C11, 93 (1999)
  Neubert, Rosner Phys. Lett. B441, 403 (1998)
• Neglect I1 amplitudes based on Bose-Einstein
  statistics and non-obvious for large resonances

PRELIMINARY
a-aefflt11o _at_ 68C.L.
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rr measurement of a
PRELIMINARY
61752 signal events
a (100 13)o
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Combining pp,ppp and rr from BaBar
PRELIMINARY
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Measurements of g
B?rr
a
g
b
Dp, D0K
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D0K Dalitz analysis the idea
A(D0 ? f)
D0K
Critical parameter
Sensitive to sin?
B
fK
A(D0 ? f)
D0K
rb eig
D0?Kspp Sensitivity to g
f CP eigenstate ? measure g f DCS ? measure
rb f3-body ? measure both
fKsr
fDCS Kp
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D0 ?Kspp results
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Bayesian C.L.s
g 70261010(Dalitz)
PRELIMINARY
(90 C.L.)
DK rB lt 0.19
dB 11441810(Dalitz)
DK rB 0.155
0.070
0.040 0.020
-0.077
dB 303341410 (Dalitz)
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The status of the triangle
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perhaps more impressive
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Measurements of Vub

• Including b?sg studies and search for B?tn

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Vub and semileptonic B decays

• Vub determines the left side of the UT
• Precise Vub and sin2b ? strong constraint on
  the UT
• Uncertainty on Vub is dominated by theory
  errors, hence
• Exclusive B ? p lv, rlv, wlv,
• Better S/B, esp. if weve tagged one B
• Theory (LCSR, LQCD, etc.) must predict form
  factors
• Theory error hard to quantify
• Inclusive B ? Xulv
• Use difference in kinematics to separate ulv
  from clv
• Need to estimate efficiencies
• Theory (OPE, SCET) must predict signal spectra
• Current theory error 10-15 of Vub

Br as a function of q2
B?sg spectrum
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Measured q2 and FormFactors
PRELIMINARY

• Recent LQCD and LCSR calculations agree well with
  data
• ISGW2 shows marginal agreement for pln errors
  for rln too large to fit 3 FFs.

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Br(B?Xuln)and Vub
Inclusive Vub ICHEP 2004

• Using FF normalization from LQCD2
• Average central value
• Good agreement with q2 shapes

PRELIMINARY
Best exclusive measurement of Vub Comparable to
inclusive measurements but with uncorrelated
theory errors
Vub3.820.14st0.24sys0.11th0.57FF
17 error
Measure also Br(B?Xuln)
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b?s g
b motion
mb/2
1.9GeV
Exp acceptance
Largest uncertainty on Vub measurement b?ul?
comes from b motion inside B meson ? b?sg
allows to measure it
Also sensitive to new physics in penguin diagrams
c-
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Fully inclusive analysis
Subtract continuum (off-resonance) Detailed
control of B background (?0, ?0, neutral
hadrons, e-) MC validation
Lepton tag event shape to suppress background
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Moments and Shape Function

• First, second and third moments of photon
  spectrum can be utilized to constraint the b
  quark motion in meson
• Direct impact on error on Vub
• Great improvement wrt existing constraints

Kagan-Neubert model
Aiming at bringing error on Vub down from 10 ?
5
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Search for new physics

• t?mg
• X(3872)

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Lepton Flavour Violation Search in t?µ?

• BaBar is a t Factory. stt 0.89 0.02 nb
• Lepton Flavour Violation
• Some supersymmetric models predict rates for
  t?µ? parts per million
• but rates from most Standard Model (SM)
  extensions are much lower.
• Any observation of this mode would indicate new
  physics.
• Search for tt- decays with
• non-SM decay of t with isolated µ and ? with
  invariant mass of t in one hemisphere and t
• SM decay of other t to 1 or 3 charged pions.

PRELIMINARY
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t?µ? and SUSY
BaBar hep-ex/0502032
Hisanu, Shimizu hep-ph/0303071 Several scenarios
already ruled out
BaBar allowed
SfKs(WA)
SfKs(WA)
BaBar allowed
SfKs
SfKs
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Towards a new spectroscopy(?)

• Recent observations of new states (DsJ,
  X(3872),) several models have been developed
• We are at a stage where we can start to
  discriminate among them
• e.g molecular model predicts highly suppressed
  B0?X(3872)Ks
• 4-quark model predicts different masses
  between X(3872) in B0 and B decays
• DMgt5 MeV

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Search for B0?X(3872)Ks
PRELIMINARY
PRELIMINARY
B?X(3872)K
B0?X(3872)Ks

• N8.44.5 2.7s
• mX(3868.61.2)MeV

N5114 6.9s mX(3871.30.6)MeV
DM(2.71.30.2)MeV
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The future

• BaBar will run until summer 2008 at least. By the
  end of 2006 should have got to a L2 1034 cm-2s-1
• Belle that is now running at L1.5 1034 and is
  integrating 1 fb-1/day (impressive, eh ) will
  also increase its performances and run till the
  end of decade

It is conceivable and even likely that the two
experiment will eventually integrate 3-4ab-1
(TBC with 0.6 now)
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Hence, we can project
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Conclusions

• The beautiful alphabet (?????) is well on the way
  to be precisely decoded
• The Bd physics will be practically done at the
  B-factories
• Whether the New Physics will decide to manifest
  itself at these Beauty-factories it is not given
  to know yet
• We keep doing our best to be ready just in case

Thank you