babar winter highlights
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BaBar Winter Highlights. SLAC Experimental Seminar April 3, 2007 For the BaBar Collaboration. Jim Olsen Princeton University BaBar Physics Analysis Coordinator. Data input and physics output. Publication “Luminosity”. Run 6. BaBar Publications. Journal Publications - PowerPoint PPT PresentationTRANSCRIPT
BaBar Winter HighlightsJim Olsen
Princeton UniversityBaBar Physics Analysis Coordinator
SLAC Experimental Seminar
April 3, 2007
For the BaBar Collaboration
Data input and physics output
Peak luminosity
(cm-2s-1)1.201 x 1034
Best shift 329.7 pb-1
Best day 891.2 pb-1
Best week 5.25 fb-1
Best month 18.84 fb-1
BABAR logged 414 fb-1
BABAR Belle
Luminosity 413fb-1 710fb-1
Journal Papers
270 206
Publication “Luminosity”
Run 6
BaBar Publications
• Journal Publications– Submitted: 270 (15 in 2007)– Published: 248– About half PRL, half PRD
• Ongoing Analyses– New results for winter: > 30– Targeted for summer: > 100
Electron-Positron Annihilation @ s = 10.58 GeV
nb1))4(( BBSeenb3),,, ;( csduqqqee
ee → Cross-section (nb) Applications
ee(), () > 40 Luminosity, boost, calibration, control samples,…
0.9 Control samples, tau physics: LFV, spectral moments, form factors,…
hadrons + variable ISR physics: QED, QCD, a, quarkonia, new states,…
cc 1.3 Charm physics: production, decay, spectroscopy, D mixing, CPV,…
uu, dd, ss 2.1 Inclusive particle spectra, bkgs,…
Non-B physics accounts for ~25% of all BaBar publications
Bulk of BaBar effort is in B physics:
• CKM elements: Vub, Vcb, Vtd, Vts
• searches for CP, T, and CPT violation
• searches for rare and forbidden decays
• hadronic B decays, HQET,…
Publications by topic*
65
16
56
45
24
12
68
0
25
50
75
Angles Semilep Charmless B to charm Lept/RadPeng Mixing/Lifetime Non-B
*some papers cover multiple areas
BaBar Winter Results at a GlanceBeta • sin2 from (c cbar) K0
• sin2 with D*D and DD
• sin2 with D0(CP) h0 decays
• sin2b in B0 → KSKSK0
• sin2b in B → KS
Alpha • observation of CP violation in B0 → h+h-
• BF and Acp in B →
• Time-dep CP asymmetry in B →
•Time-dep Dalitz in B →
• Evidence for B0 →
• Time-dep CP asymmetry in B0 → a1
• BF(B → K1)
Semileptonic B Decays • Decay rates for B → (D, D*, D**)l
• Vcb and form factors in B → D*l
Gamma • Measurement of in B → D0(K
Radiative Penguins• Evidence for B →
• Search for B → l+l-
Charmless Hadronic B Decays• Observation of B → KS
• Angular analysis in B → K*
• Search for B → K*K
• Search for a0h and f0
Hadronic B Decays• Angular analysis of Charmonium K*
• Measurements of B → J/
• B → p
Non-B Physics• Evidence for D0 mixing
• Search for D0 mixing in semileptonic decays
• Measurement of c branching fractions
• Form factors in D → Ke
• Observation of e+e- →
• Observation of e+e- →
• → l(’
Outline
• D mixing• New results on CP violation• New results on spectroscopy and QCD
See SLAC seminar by Brian Petersen for details: https://www.slac.stanford.edu/exp/seminar/talks/2007/20070314_BrianPetersen_BaBar_Dmixing.pdf
Evidence for D0 Mixing
press release on D mixing
DOW plummets 200 points
Charm-Meson Mixing (SM)short distance ~ x ~ m long distance ~ y ~
O(10-5) O(10-3 - 10-2)
1%Most calculations give:
x,y < 1%
“D0-D0 mixing is expected to be too small to measure with BaBar if the Standard Model
is a complete description of physics.”
- BaBar Physics Book (1998) cf. A. Petrov, hep-ph/0611361, and references therein
Charm-Meson Mixing (NP)
1%
Signs of New Physics:
|x| >> |y|
CP violation
New particles enter primarily in the short distance contribution (x):
Suppression of new FCNCs via quark-squark alignment predicts “large” effects in D-D mixing: Y. Nir and N. Seiberg, hep-ph/9304307 (1993)Y. Nir, hep-ph/0206064 (2002) cf. A. Petrov, hep-ph/0611361, and references therein
Constraining the Squark Mass Matrix
Squark mass matrix (d sector)
LHC
B Factory,Tevatron
Observation of D-D mixing opens a new window on the off-diagonal elements of the squark matrix in the up-quark sector
Analysis of D0 → K
2
22
4t
yxtyRRe
dt
dNDD
t
KDD
KD00
0
Mixing modifies the exponential decay-time distribution:
Two paths to the “wrong-sign” state:
DCS
interference
mixing
sincos
sincos
xyy
yxx
Strong phase → 0 in SU(3) limit
(DCS decays)
(Mixing)
Evidence for MixingWrong-sign decay-time distribution
%31.044.097.0
%021.0030.0022.02
y
x
3.9hep-ex/0703020
Submitted to PRL on March 9
2/ndof = 50/282/ndof = 31/28
Mixing gives a better description of the data
No evidence for CP violation
2
22
4t
yxtyRRe
dt
dNDD
t
First assume no mixing:
Comparison of BaBar and Belle
BaBarpreliminary
Belle Ks
Belle KK,
Full interpretation depends critically on the strong phase: “My call: SU(3) violation” – J. Rosner (Moriond QCD)
Assuming → and no CP violation
CP Violation
CP Violation and the Unitarity Triangle
0*** tbtdcbcdubud VVVVVV
*cbcdVV
*tbtdVV
Length of each side ~ O(3)
*ubudVV
),(
*cbcdVV *
cbcdVV
)0,1()0,0(
CP 0
“The” Unitarity Triangle
Sides are determined from the rates for various processesAngles are determined from CP-violating asymmetries
Area is proportional to the amount of CP violation
Goal of the B Factories is to overconstrain the apex
(,) and look for inconsistencies → New
Physics!
Observing CP violation at the (4S)
CP violation in mixing (|q/p| ≠ 1)0000 BBBB
(indirect) CP violation in the interference between mixing and decay: Im(q/p) ≠ 0
Three possible interference effects:
00
00
BqBpB
BqBpB
H
L
CP if q ≠ p
)cos()sin(
)()(
)()(00
00
tmCtmS
fBfB
fBfBA
CPCP ff
CPCP
CPCPCP
Indirect CPV Direct CPV
(direct) CP violation in decay:
CPCP fBfB 001/ AA
Indirect CP Violation: experimental method
)cos()sin(
)()(
)()(00
00
tmCtmS
fBfB
fBfBA
CPCP ff
CPCP
CPCPCP
t
0tagB
+e-e
0CPB
t = 0
K
e+
0SK
/J
(4S)
Lepton Tags: mistag rate ≈ 8%
Kaon Tags:mistag rate ≈ 18%
fS = sin2
Asy
mm
etr
y 1z
tc
m260 z
m180
~
~σ(Δz)
New results on sin2 in b → ccs
018.0025.0966.0
016.0035.0697.02sin
017.0022.0952.0
018.0032.0714.02sin
f = -1
f = +1
NBB = 383 million pairs
Golden modes (JK0)
BaBar Preliminary (hep-ex/0703021; submitted to PRL)
B Factory Average
0.13.21 0.17.68 Disfavored by J/K*, D*D*KS, D0h0
Latest on sin2 in Penguins
sin2 in b → cud: B0 → D(*)0(CP)h0
Interference between mixing and the b → cud decay tree amplitude when the D0 decays to a CP eigenstate
No penguin amplitude, NP must enter at tree level:
Ex. R-parity-violating SUSY with baryon number violation
Y. Grossman, Y. Worah, Phys. Lett. B 395 (1997) 241-249
Longterm goal: compare sin2 in charmonium, b → s penguin, and b → c tree
sin2 in b → cud: B0 → D(*)0(CP)h0
Decay modes:
• D*0 → D0
• D0 → KK, KS
• h0 →
BaBar Preliminary
BaBar Preliminary
CP even
CP odd
sin2 in b → cud: B0 → D(*)0(CP)h0
40.016.023.0
05.023.056.0
C
S
First measurement of sin2 in these modes
hep-ex/0703019, submitted to Phys. Rev. Lett.
Fully consistent with the world average
for sin2 in charmonium,
another victory for the standard model!
SM expects S = -sin2, C ~ 0
sin2 in b → ccd: B0 → D(*)+D(*)-
B0
D(*)+
D(*)-
B0
D(*)+
D(*)-
• Two decay amplitudes interfere– b → c tree diagram with S = -sin2– b → d penguin diagram with S ~ 0
• Penguin is expected to be small– ~2-10% (PRD 61, 014010, 2001)
Standard Model predicts:
%10~
2sin
C
S
Belle sin2 in b → ccd: B0 → D+D-
Belle @ CKM 2006
(NBB = 535 million pairs) )2.3( 06.023.091.0
09.037.013.1
A
S
B0 B0
BaBar sin2 in b → ccd: B0 → D+D-
BaBar @ Moriond EW
(NBB = 383 million pairs)
70.022.011.0
06.034.054.0
C
S
S consistent with sin2 in charmonium, no evidence for direct CP violation!
Note the sign flip: C = -A, C(BaBar) – C(Belle) = 1.02 ± 0.33!
BaBar Preliminary
@ICHEP06BaBar: 347 MBB
Belle: 535 MBB
CP Violation in B0 → h+h-
How to add data over a shutdown
Use dE/dx for tracks with no c
DCH DRC
+12% from forward coverage
+9% from cracks in barrel
+16% overall in B+ → h+X0
+35% overall in B0 → h+h-
dE/dx /K separation competitive in the forward region high momentum
Observation of CPV in B0 → h+h-
Belle
)5.5( 018.0107.0
)2.2( 02.009.021.0
)2.5( 03.011.060.0
007.0 004.0
KA
C
S
824372
491139
KN
NBaBar Preliminary (hep-ex/0703016; submitted to
PRL)
Now more events/fb-1 than Belle!
BaBar: 383 MBB
Time Evolution of S
2000 2001 2002 2003 2004 2005 2006 2007
The problem with …S sin2eff = sin2( )All modes suffer from “penguin
pollution” due to b → d transition
Use isospin to relate the decay amplitudes for the various modes and set a bound on the shift in
Optimal Case: 000 ,
B → o
hep-ex/0612021; accepted by PRL
B → o
hep-ex/0607106
A New Direction: B → a1
0B
0BFirst observation of B → a1
+
Phys. Rev. Lett. 97, 051802 (2006)
BaBar
hep-ex/0612050; accepted by PRL
First time-dep CP asymmetry in B → a1+
Similar to , but no overlapping regions in phase space where a1
+, a1
-, and a10 can interfere directly
Possible solution: Use SU(3) to relate a1a1K, and K1
BaBar
?,779eff
First Step: B → K1
effeffeff 2
1
SU(3) relates K and a1 K1A:
related to K1 related to a1K
Experimental problem: • K1A is an admixture ( ~ 33o)
)1270(sin)1400(cos 111 KKK A
Wide overlapping resonances
First pass: quasi-two-body approach
Gronau & Zupan, Phys. Rev. D73, 057502 (2006)
Results for B → K1
Evidence for K1(1400), but large correlation with K1(1270) complicates the interpretation• Full analysis, including interference term, is underway
• next step: a1K
BaBar preliminary
sPlot constructed from a fit using mES, E, and event-shape info:
• data points do not use MK
• curves are the result of the full fit
Spectroscopy and QCD
Spectroscopic Mysteries
DsJ(2700)
Open CharmCharmonium-like
New BaBar results using B → D(*)D(*)K
DsJ(2700) @ BelleFirst observed by Belle (hep-ex/0608031)
KDDB 00
Potential model: cs(23S1)(expected mass @ 2720)
M. A. Nowak, M. Rho, I. Zahed, Acta Phys.Polon. B 35, 2377 (2004)
Chiral symmetry: 1+ - 1- doubletpaired with DsJ(2536)
S. Godfrey and N. Isgur, Phys. Rev. D 32, 189 (1985)
DsJ(2700) @ BaBar
KDDB 0(*)0(*)
BaBar confirms a broad enhancement near 2.7 GeV, but is it one resonance or two? Possible low-mass structure in DK.
Next step: full Dalitz analysis
X(3872)
JXKXB )3872(,)3872(
X(3872) first observed by Belle JXKXB )3872(,)3872(
Observation of J/ mode → C = +1
Belle angular analysis → JPC = 1++
Inconsistent with expected charmonium states
Search for X(3872) in D*D
24.07.1 cVM9.0 7.04.3875 eM
PRL 97, 162002(2006)
000*
*
DD
DKDB
KDDB 000 Belle: BaBar:
24.15.1 cVM 7.06.3875 eM
X(3875)?
Observation of ee →
Exclusive reactions allow fundamental tests of QCDSingle photon (JPC = 1--)
e-
e+
For vector gluons:
d/dcos ~ sin2*
Two-Virtual Photon Annihilation (C = +1) followed by FSI → unlikely?
In the CM frame:
u
u
u
u
d
u
d
u
BaBar observation of TVPA process in , → good agreement with theory:B. Aubert et al., Phys. Rev. Lett. 97, 112002 (2006); G. Bodwin et al., Phys. Rev. D74, 074014 (2006)
Observation of ee →
0 m
0 mFit in (m-, m+) plane:
• signal = p-wave relativistic BW
• = threshold function
• comb = linear
N = 308 ± 25 signal events (> 5)e+e- → = (20.0 ± 1.6 ± 3.6 ± 1.7)fb (stat) (syst) (ampl)
Angular Distributions
2
00
2
11
2
10 01.0~ FFF
Use mass fit to produce sPlots for various angular distributions, then perform fit over the sPlot bins
± = ± helicity angle
± = azimuthal angle of in frame
scattering angle in the CM frame
Prediction (single :
Brodsky and Lepage, PRD 24, 2848 (1981)
Angular Distributions: Results
(syst)00.0(stat)03.004.0
(syst)01.0(stat)04.010.0
(syst)02.0(stat)14.051.0
2
11
2
10
2
00
F
F
F
Results:
BaBar PreliminaryFit normalization constraint:
1242
11
2
10
2
00 FFF
|F00|2 ≠ 1
(e+e- → ) > (e+e- → )
No evidence for Y(4S) →
Are we seeing TVPA + FSI?
Summary and Outlook
• BaBar did not hibernate this winter– >30 fresh results for the winter workshops/confs– Highlights
• First evidence for D0 mixing• Many new results on CP violation, including first observation
in from BaBar• New results in spectroscopy and QCD
• We are approaching 300 papers submitted!– Wide range of physics topics, no signs of slowdown
• Looking forward to ~500fb-1 and >100 new results for the summer season!