The BABAR Experiment: Status and Plans - McGill Physics40 layer drift chamber (dE/dx) 1.5 T solenoid...
Transcript of The BABAR Experiment: Status and Plans - McGill Physics40 layer drift chamber (dE/dx) 1.5 T solenoid...
The BABAR Experiment: The BABAR Experiment: Status and PlansStatus and Plans
Steven RobertsonInstitute of Particle Physics
Canadian Association of Physicists Congress 2008
Québec City, Québec June 10, 2008
Sep 3, 2008 2Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
OutlineOutline
● Flavour physics overview● The BABAR experiment and B factory operations● Run 7 and ongoing analysis activities● Some recent Canadian highlights
Sep 3, 2008 3Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Why Flavour?Why Flavour?Flavour sector contains 20 (22) of 25 (27) parameters of the SM, which
are intrinsically connected to EW physics and symmetry breaking ● Tantalizing structure (similarly for lepton sector) which is not predicted
by the SM:
● All known CP violation phenomenology arises from a single complex phase in VCKM
● B sector provides access to a substantial fraction of the CKM matrix either at tree level or via one-loop processes
● Indirect probes of New Physics from “redundant” determinations of CKM parameters or from rare decay searches D0
π
Β+
u
ud
b c
u
Vcb
V*ud
Vud Vus Vub
V = Vcd Vcs Vcb
Vtd Vts Vtb
Sep 3, 2008 4Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Effective theory approachEffective theory approach
In explicit models:● Λ ~ mass of virtual particles
(e.g. Fermi theory.: mW)
● C ~ (loop coupling) x (flavour coupling)
(e.g. SM/MFV: αw x CKM)
New Physics scaleEffective flavour-violating couplings
Increasing luminosity
Precision flavour measurements provide bounds on ratio C / Λ i.e. they constrain coupling strengths at any given mass scale
● Loop-level flavour processes (FCNCs) can act as probes of mass scales far beyond the CM energies of accelerator-based experiments
Sep 3, 2008 5Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Unitarity Triangle constraintsUnitarity Triangle constraints● Unitarity of CKM matrix implies relationships between CKM
elements which can be tested experimentally
● Bd meson Unitarity Triangle (UT):
● “Tree-level” determination of UT parameters permits the SM mechanism for CP violation to be tested
B → ψKS
B → φKS
B0 → D*π B+ → D0
CP K+
α
γ β
Vtd V
tb *
VcdVcb*
V udV ub
*
B0 → π+π−
B0 → ρ+ρ−b → ulν
b → clν
B0B0 mixing
Sep 3, 2008 6Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Trees vs penguinsTrees vs penguinsUnitarity of CKM matrix implies relationships between CKM elements
which can be tested experimentally
● Bd meson Unitarity Triangle (UT):
B → ψKS
B → φKS
B0 → D*π B+ → D0
CP K+
α
γ β
Vtd V
tb *
VcdVcb*
V udV ub
*
B0 → π+π−
B0 → ρ+ρ−b → ulν
b → clν
B0B0 mixing
● “Redundant” determinations of UT parameters in modes which proceed via different mechanisms (i.e. tree vs loop) can yield information about possible New Physics contributions
B0
K0
J/ψb→ccs
New Physicss
ds/
dd
g
b
ds/
s~b~
g~
K0
ϕB0
b ss
sd
dg
, ,u c t
W+
K0
B0ϕ
b→sss
Sep 3, 2008 7Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Trees vs penguinsTrees vs penguins● Determination of sin2β from
b→ccs modes consistent with overall CKM fit (both including and excluding kaon constraints):
● Determination of sin2β from penguin-dominated modes not as clearly consistent with SM expectation:
Sep 3, 2008 8Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Rare decaysRare decaysSearches for “rare” decay processes can provide additional NP
sensitivity since the NP contribution may be comparable or larger than the (suppressed) SM rate● Leptonic B, Ds or D decays:
iq jqiq jq2q 23(13)(m )
● Flavor-changing neutral currents (FCNCs)
● Lepton flavour violation (e.g. in τ decays):
Sep 3, 2008 9Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
The BABAR experimentThe BABAR experiment
● Currently ~350 physicists from eleven nations
Sep 3, 2008 10Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
ϒϒ(4S) (4S)
B0B0 pair is produced in a coherent L=1 state
The ϒ(4S) is a bb resonance which lies just above the mass threshold for production of BB meson pairs.
● Cross section of ~1.1nb
~1.1 million BB pairs per fb-1
OffOn
PEP-II BABAR
BB
thre
shol
d
ECM -M Υ(4S) (MeV)
The two B mesons evolve in phase until one decays
(EPR situation)
⇒ Enables studies of time-dependence of decays of “flavour-tagged” neutral B mesons
Sep 3, 2008 11Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
PEP-II Asymmetric B FactoryPEP-II Asymmetric B FactoryFirst collisions: 1998Final collisions: April 2008Collide 9.0 GeV electrons with3.1 GeV positrons for ϒ(4S)
CM Energy = 10.58 GeVDesign luminosity 3.0 x 1033 cm-2 s-1
Record luminosity 12.07 x 1033 cm-2 s-1
Number of bunches: 1720
Beam current: (HER) 1.875 A (LER) 2.9 A
Sep 3, 2008 12Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
The The BBAABBARAR detectordetector
e-
(9.0 GeV)
e+ (3.1 GeV)
EM calorimeter6580 CsI(Tl) crystals
σpT/pT = (0.13 · pT /[GeV/c] + 0.45)% 40 layer drift chamber (dE/dx)
1.5 T solenoid
5-layer silicon vertex detector
DIRC – RICH utilizing total internal reflection
BABARK-π separation
pLAB (GeV/c)
K-π
sepa
ratio
n(σ)
Magnet flux return instrumented with RPCs (→ LSTs)
B factory operations at SLAC since 1999:● Centre of mass energy of 10.58 GeV
for ϒ(4S) → BB● Asymmetric beam energies produce
boost of βγ=0.56 in lab frame
Sep 3, 2008 13Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
BABAR/PEP-II OperationsBABAR/PEP-II Operations
● Final BABAR ϒ(4S) “onpeak” data sample corresponding to an integrated luminosity of 430 fb-1 ~0.5x109 BB pairs● substantial samples of
continuum tau and charm● also ~45fb-1 of ϒ “narrow
resonance” data (surprise!)...●
Sep 3, 2008 14Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Interesting times...Interesting times...Run plan for Run 7 approved until Oct 2008 with luminosity target of
~2x1034 with anticipation of an additional ~50% new data ● substantial upgrades to accelerator during 3-month shutdown in fall 2007● BABAR IFR (barrel muon system) upgrade completed prior to 2007 run
Dec 21st – Congressional budget cuts (targetted at ILC) result in termination of BABAR run effective Jan 1st 2008● BABAR successfully argues
that physics case for ϒ(3S) & ϒ(2S) justifies a 3-month extension of the run
● PEP-II/BABAR retool accelerator, detector and trigger system within a 3-day period over the holiday break
Continuesto Oct 2008
End of ϒ(4S) Run
ϒ(3S) Run ϒ(2S) Run
Scan
Sep 3, 2008 15Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Final OperationsFinal Operations● Monday April 7th 2008 (12:43PM)
Sep 3, 2008 16Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
30.2/fb@ Y(3S)
4.2 0.2( ) nb ( 5% syst.)~120M (3S) (x10 Belle, 25x CLEO)
stat ϒ
7.3 0.3( ) nb ( 7% syst.)~100M (2S) (~12x CLEO)
stat ϒ
14.5/fb@ Y(2S)
Narrow Upsilon PhysicsNarrow Upsilon Physics● New element of BABAR physics
program: Upsilon spectroscopy!● Search for elusive singlet states
(ηb and hb)
● Hadronic transitions, etc.● New Physics searches● Invisible width of ϒ(1S), etc.
● World largest samples by one order of magnitude
●
●
Sep 3, 2008 17Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Direct Higgs/DM searches (?!)Direct Higgs/DM searches (?!)
Can have either completely invisible final states, or (invisible + γ), depending on spin of the mediator● Require a “tag” to identify that the event has occurred
● Expected sensitivity with BABAR ϒ(3S) data sample Br(ϒ(1S) → invisible) ~few x 10-4 (prelim results “soon”)
●
● Light (pseudoscalar) Higgs and/or light dark matter candidates can be directly produced in decays of heavy quarkonium states:*
● ϒ → χχ via U (new gauge boson or scalar)
● ϒ → A1 γ where A1 → χχ or τ+τ-
Models manage to evade existing Higgs & SUSY LSP limits from e.g. LEP, while predicting quite large branching fractions
*B. McElrath, Light Higgses and Dark matter at Bottom and Charm Factories, arXiv:0712.00116v2 [hep-ph]J. Gunion, D. Hooper and B. McElrath, Light Neutralino Dark Matter in the NMSSM, hep-ph/0509024.
Sep 3, 2008 18Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
High Energy ScanHigh Energy Scan● Last ~two weeks of Run 7 were dedicated to an energy scan of
the region above the ϒ(4S)
● 25 MeV steps, 25pb-1 per point (previous scans by CLEO and CUSB in 1984 based on ~100pb-1)
● Motivation: study properties of ϒ(5S) and ϒ(6S) resonances, search for exotic bb states (analogous to “unexpected” Y(4260),Y(4350),Y(4660) charmonium-like states)
● Clear evidence of ϒ(5S) and ϒ(6S) resonances, but not a simple resonance structure● interference contribution?
● ⇒ Results “soon”...
Sep 3, 2008 19Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
What next?What next?● 3-month transition period to prepare detector for “Minimum
Maintenance State” (MMS) ● Detector could (with difficulty) be brought back into service from MMS● Requires continuous monitoring (e..g gases, fluids) but no expert shifters
● “Decommissioning and Disposal” (D&D) to begin in late 2008 or 2009● Planning underway – requires
agreement between BABAR member countries
● Important to preserve valuable/unique hardware assets
● BABAR collaboration retains ownership of the detector until the end of MMS phase● The lab will assume ownership at
the end of MMS and the responsibility for the D&D
Sep 3, 2008 20Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Detector reuse for SuperBDetector reuse for SuperB
Super-conducting solenoid
CsI(Tl) barrel calorimeter and support structure
DIRC quartz bars
Muon system iron/flux return (?)
● SuperB project (see talk in Monday morning session) assumes reuse of significant portions of the existing BABAR detector
⇒ Complicates D&D phase (issues of ownership, disposal and transportation costs etc)
Sep 3, 2008 21Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Post data-taking periodPost data-taking period
Post data-taking “intense analysis period” had been anticipated to begin in Oct 2008 following completion of ϒ(4S) run with total data set expected to be >700fb-1 of onpeak data
● Final “onpeak” ϒ(4S) data sample of ~430fb-1 ● Over 100 “core” analyses expected to be performed/updated with full
data sample● Many, many other analyses also currently in progress on topics
ranging from new states, τ and charm physics, ISR physics, rare decay searches, B decays etc.
● New narrow-resonance studies well underway
No evidence so far of any slowdown of analysis activities...● 130 BABAR abstracts submitted to ICHEP08, 20(+2) talks!
⇒ SLAC has commited to providing computing resources through the intense analysis period – currently no obvious resource issues
Sep 3, 2008 22Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Published 320 PRL 165 PRD 66 PRD(RC) 114
Total Submitted 345
Publication statisticsPublication statistics
Sep 3, 2008 23Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Publication statisticsPublication statisticsSustained publication rate of over 1 paper/week over the past
four years! ● Very rich physics program: only ~half of all papers relate directly
to primary BABAR program of CKM / CP violation
Sep 3, 2008 24Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Publication statisticsPublication statistics● Asymmetric B factories still have only a very short history:
CP violation in B decays proves CKM mechanism
Current BABAR grad students are born
Sep 3, 2008 25Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Leptonic and LFV B decaysLeptonic and LFV B decays● Use hadronic tag reconstruction method to
search for leptonic and lepton flavor violating B decay modes ● Two-body decays yield clean signature in
signal B rest frame
B+ B-ϒ(4S)µ+ K-
π+
π-ν
PRD-RC 77, 091104 (2008)
Mode Data Sample 90% CL limit
Sep 3, 2008 26Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
VVusus from inclusive from inclusive ττ→K→K decays decays● New precise BABAR measurements of τ decays to final states with charged kaons ● branching fractions consistent with, but
lower than, previous measurements
Sep 3, 2008 27Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
VVusus from inclusive from inclusive ττ→K→K decays decays
Currently a 3.4σ discrepancy with CKM unitarity!
● Will be interesting (and important) to see results from other modes
● Bfactories each have O(103) more data than LEP
K. M
altman, C
.E. Wolfe, S. B
anerjee, M.R
oney, I. Nugent
Sep 3, 2008 28Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
BABAR SymposiumBABAR Symposium
● One-day symposium planned for Monday October 27, 2008 at SLAC to celebrate the achievements of BABAR/PEP-II
● Announcement/invitations anticipated to be sent out around mid-June
Sep 3, 2008 29Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
ConclusionConclusion● BABAR is still going strong, in spite of the untimely termination of the
data taking phase● Interesting (and unexpected) expansion of the physics program to
include ϓ(3S) and ϓ(2S) bottomonium runs and a cross section scan above the ϓ(4S)
⇒ First results anticipated for ICHEP08
“Intense Analysis Period” is well underway (and living up to its name...)● Full ϓ(4S) data set is in hand, many analysts freed from operational
responsibilities● Expected to be a record year for BABAR publications
Canadian groups very active and productive, with interesting physics results spanning the spectrum of the BABAR program
(B semileptonic and rare decays, charmonium and exotica, Upsilon physics, tau decays etc)
Sep 3, 2008 30Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Backup slidesBackup slides
Sep 3, 2008 31Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
The Flavour ProblemThe Flavour ProblemLoosely stated, generic New Physics would imply observable effects
which are are inconsistent with experiment unless either the New Physics scale is high (e.g. 1-0-100TeV) or the (loop x flavour) couplings are small
● F=2 processes occur at the loop level, thus could receive O(1) NP corrections but effects > ~20% are excluded
NP < 1 TeV● suppression of flavour violating couplings required in all sectors
possibly pointing to MFV. SUSY can stabilize the Fermi scale with mild fine-tuning
If 1< NP < 10-100 TeV● suppression of flavour violating couplings needed in sector 1-2 only.
No indication of MFV. SUSY can still stabilize the Fermi scale with moderate fine-tuning
Sep 3, 2008 32Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
New Physics Bounds from New Physics Bounds from τ→µγτ→µγ
Sep 3, 2008 33Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
CP violation in interferenceCP violation in interference
0B
0B
CPfCP
mixing
decay
t=0
tCPfA
CPfA
~e-2iβ
● Combination of two decay amplitudes to the same final state manifests as an “interference pattern” in the measured decay rate as a function of decay time
λfCP ~ e-2iβ (AfCP /AfCP )
● Measure CP violation in the interference between the decays of mixed and unmixed B0 decays
Sep 3, 2008 34Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Sensitivity (MFV) ~200GeV
Present Flavour ContraintsPresent Flavour Contraints
2 2 2
2
d
NP
q
SMi B B
SMB
C Q QeQ
φ Δ Δ
Δ
1034 luminosity gives measureable effects if NP is at the EW scale
BABAR/Belle purpose: “test SM mechanism for CP violation”
E.g. Model independent parameterization of New Physics contributions to B mixing amplitudes:
Sep 3, 2008 35Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
ΔF=2 parameterizationΔF=2 parameterization
Sep 3, 2008 36Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
FCNC decaysFCNC decays● Flavour changing neutral current (FCNC)
processes do not occur in SM at tree level● Loop-mediated processes can have large
contributions from non-SM diagrams of same order as leading SM contributions:
●
●
Products of field operators(nonperturbative hadronic matrix elements; HQE in inverse powers of mb)
Wilson coefficients (calculated perterbatively; encode short-distance physics)
● Low-energy effective Hamiltonian for b →s (or d) transitions:●
● New Physics can enter via non-SM values of Wilson coefficients
cc
ss
tt
bb
uu
dd
SM dominated by t-quark contribution
Sep 3, 2008 37Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Electroweak FCNCsElectroweak FCNCsB → Xs/d γ
C7 (Photon penguin) only
Observables: branching fractions Eγ (or mhad) spectrum, ACP
B0s/d → l+l-
C10 (Axial vector EW) only
Observables: branching fractions
B → Xs/d l+l-
C7 ,C9 (Vector EW) and C10
Observables: (partial) branching fractions, dilepton AFB, ACP
New physics could result in a distinctive pattern of deviations in observables across a variety of related FCNC modes
Sep 3, 2008 38Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Trees and PenguinsTrees and Penguins● Time-dependent CP asymmetries in b→ccs, b→sss, b→qqs
(q=u,d)● b→ccs is tree decay clean sin2β measurement● b→sss purely penguin decay: sin2β in Standard Model
● (0.05 hadronic), sensitive to heavy particles in loops● “New Physics” potentially contributes at same order as Standard Model
● b→qqs proceeds via penguin diagrams and b→u tree diagrams
b ss
sd
dg
, ,u c t
W+
K0
sds /
dd
g
b
ds /
s~b~
g~
b sd
dd
d
W+
g
, ,u c t
B0K0B0
b→ccs
b→sss b→dds
New Physics
π0
Sep 3, 2008 39Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Beyond Tree Level...Beyond Tree Level...
● Uncertainties from Vub and fB cancel in ratio of modes!
● ⇛ Can we get there???●
● Tree-level charged Higgs (Type-II 2HDM or MSSM) contribution has the same effect on all leptonic modes:
● B(B+→l+ν)MSSM = B(B+→l+ν)SM x [ 1 – (m2B/m2
H+) tan2β/(1+ϵ0 tan2β) ]2 ● “Universality” preserved at tree level
● At one-loop level, potentially large Lepton Flavour Violation (LFV) effects entering from e.g. SUSY in grand unification scenarios:
i.e. B+ → l+ νl' where l' ≠ l via effective l H+ ν coupling
Observable effects in ratios, Rbl/τ, of B leptonic branching ratios:
●
G. Isidori and P. Paradisi hep-ph/0605012A. Masiero, P. Paradisi and R. Petronzio hep-ph/0511289
Sep 3, 2008 40Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Lepton Flavour ViolationLepton Flavour Violation● In Standard Model, lepton flavour conservation is not associated
with any underlying symmetry principle● LFV generally permitted in New Physics models containing more
than one Higgs doublet● In SUSY seesaw models, flavour changing insertions arise from Yukawa
couplings in the slepton mass RGEs:
● ⇛ New Physics effects in τ → l γ (l = e,µ) can saturate experimental bounds in natural and well-motivated models
● MSSM with heavy right-handed neutrinos and seesaw mechanism: Br~10-7 ● heavy Dirac neutrinos, RPV SUSY models, flavour changing Z' models...
Sep 3, 2008 41Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Higgs mediated LFVHiggs mediated LFV● Higgs mediated LFV present in MSSM at loop level given that
there is a source of LFV among sleptons:
From A. Dedes, Super B Factory proceedings: hep-ph/0503261
Effective SUSY
● Predicts LFV effects in a variety of τ and B decay modes (with preference for 3rd generation couplings):
Sep 3, 2008 42Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
More Charmless ResultsMore Charmless Results• Observation of B → ηρ+
● Tree dominated decay
● BR in good agreement with prediction
• Searches for B → η’ η, η’ π0, η π0, ωπ0 and B → ηK0, ηη, η’η’, η(’)φ, η(’)ω
● Input to ΔS from SU(3)-based theoretical predictions
● No signal observed● All limits around ~10-6
6( ) (9.9 1.2 0.8) 100.13 0.11 0.02CP
BR BA
ηρ
9σ signif.
2.6σ signif.
FPCP 466M BB
0SB Kη
Submitted on full data set (arXiv:0804.2422)!
Sep 3, 2008 43Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
CP Asymmetries in B CP Asymmetries in B → J/→ J/ψψ ππ00
● Cabibbo-suppressed mode with respect to B → J/ψ KS and opposite CP● Expect S = -sin2β and C = 0
if tree dominated● Penguin diagram or New Physics could
modify CP asymmetries
FPCP 466M BB
0 0 5( / ) (1.69 0.14 0.07) 101.23 0.21 0.040.20 0.19 0.03
BR B JSC
ψπ
184 15signal events
4σ evidence for CP violation,consistent with tree-dominated decay
Submitted on full data set (arXiv:0804.0896)!
0-tagB
0-tagB
Sep 3, 2008 44Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
CP Asymmetries in B CP Asymmetries in B → K → K ηη γγ● Radiative penguin decay
● Photon polarization different for B and B in SM, expect no interference and thus no CPV
● New Physics could contribute with different polarization amplitudes
FPCP 465M BB
5
0 0 5
( ) (7.7 1.0 0.4) 100.09 0.10 0.01
( ) (7.1 2.1 0.4) 100.2 0.5 0.10.3 0.4 0.1
CP
BR B KA
BR B KSC
ηγ
ηγ
8 signif.σ
Submitted on full data set (arXiv:0805.1317)!
0-tagB
0-tagB0B
B
3.9 signif.σ
No significant CP violation,consistent with SM
Sep 3, 2008 45Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
0tagB
0recB
B-Flavour Tagging
ExclusiveB Meson
Reconstruction0SK
J/Ψ π+
π-
µ-
µ+
e- e+
ϒ(4S)
Δ zl-
K-
Time dependent CP measurementTime dependent CP measurement
Reconstruct decay vertex positions
Exploit correlationbetween B0 flavour and lepton charge,K charge etc
Sep 3, 2008 46Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Charmless B Decays to bCharmless B Decays to b11
• Observation of B+ → b1 K0
● 6.2 σ significance
● consistent with QCD factorization• Search for B0 → b1
+ ρ
● VA modes may shed light on polarization puzzle in VV modes
● QCD factorization predicts:
– No B0 → b1+ ρ observed !
0 61( ) (9.6 1.7 0.9) 100.03 0.15 0.02CP
BR B b KA
0 12 61 5( ) (33 17 ) 10BR B b ρ
∓
0 61( ) 1.7 10 (90% CL)BR B b ρ ∓
466M BBFPCP
Submitted on full data set (arXiv:0805.1217)!
Sep 3, 2008 47Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Semileptonic and Leptonic Decays (w/ SL tag)Semileptonic and Leptonic Decays (w/ SL tag)
● Exclusive B → Xu l ν branching fractions
● Search for B → K* νν ● SM BR prediction ~10-5, but could be
significantly enhanced by New Physics
0 4
0 4
4
4
0.7 30.5
( ) (1.38 0.21 0.07) 10( ) (0.96 0.15 0.07) 10
( ) (0.64 0.20 0.30) 10
( ' ) 0.47 10 @ 90% CL
| | (4.0 0.5 0.2 ) 10
l
l
l
l
ub
BR B lBR B lBR B lBR B l
V
π ν
π ν
η ν
η ν
0lB lπ ν 0
lB lπ ν
lB lη ν ' lB lη ν 3.2 signif.σ
0 *0 5
* 5
( ) 21 10( ) 9 10
BR B KBR B K
νν
νν
454M BB
383M BB
FPCPSubmitted on full data set (arXiv:0805.2408)!
Sep 3, 2008 48Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
● Rare EW penguin decays BRs
● Rate asymmetries (CP, isospin, e/µ) expected to be very small● Measured separately in ll-mass region
above and below J/ψ● All rate asymmetries compatible with
zero, except isospin asymmetry in low mass region for ee sample
FPCP
6
* 4
( ) (0.39 0.07 0.02) 10( ) (1.11 0.19 0.07) 10
BR B Kl lBR B K l l
0.18,low s 0.160.83 (4.2 )ee
IA σ
384M BBB B → K→ K(*)(*) l lll
Sep 3, 2008 49Steven Robertson, Institute of Particle PhysicsThe BABAR Experiment
Run 7Run 7
● Data taken between December 16, 2007 and April 7, 2008
● 30.2 fb-1 at ϒ(3S)
● 14.5 fb-1 at ϒ(2S)
● ~5 fb-1 above ϒ(4S) scan● Several ϒ(3S) analyses and
above ϒ(4S) scan targeting ICHEP 2008