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Experimental review of CKM sides at B factories. A. Oyanguren (IFIC, UV-CSIC) (BaBar Collaboration). DISCRETE 2008. V td. V ub. V cb. Introduction & outline. The Cabibbo-Kobayashi-Maskawa matrix:. V ud V us V ub V cd V cs V cb V td V ts V tb. V CKM =. - PowerPoint PPT Presentation
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A. Oyanguren (IFIC, UV-CSIC)(BaBar Collaboration)DISCRETE 2008
VVCKMCKM =VVudud VVusus VVubub
VVcdcd VVcscs VVcbcb
VVtdtd VVtsts VVtbtb
VVududVVubub** + V + VcdcdVVcbcb** + + VVtdtdVVtbtb** = 0 = 0
The Cabibbo-Kobayashi-Maskawa matrix:
(0,0) (1,0)
A
~|~|VVubub//VVcbcb||
~|~|VVtdtd//VVtsts||
From exclusive sl decays: |Vcb|: BD*, BD; |Vub|: B, B B(‘), B…
From inclusive BXc (|Vcb|) and BXu (|Vub|) decays
From Bd and Bs mixing [@ hadron colliders (md/ ms)]
From radiative decays (bd/bs)
DISCRETE 2008 A. Oyanguren 2
1
DISCRETE 2008 A. Oyanguren 3
+
-D0
-K+
X
B0B0
Hadronic or Semileptonic Tag
(4S)
Signal side
Tag side
Untagged
+
D0 -
X
B0B0
(4S) X
B0 B0(4S)
D*
Tag side
Signal side(High purity)
(High efficiency)
1200 fb-1 recorded ! 1200 fb-1 recorded !
From B D (BR ~2% , suppressed at high q2)
DISCRETE 2008 A. Oyanguren 4
VVcbcbq2
Kinematic functionForm factor
(shape & normalization)
B D D2
B D* D*2, R1(1) , R2(1)
G(1)*=1.074 0.018 0.016
* M.Okamoto et al NPPS 140, 461(2005))
F(1)*=0.921 0.013 0.020
* C. Bernard et al arXiv:0808.2519 [hep-lat]
Theory:
From B D* (BR ~ 5%)
Measuring the decay rate and ff shape |Vcb|
DISCRETE 2008 A. Oyanguren 5
Reconstruct the other B into hadrons (Btag) Reconstruct the missing mass: m2
miss = (p(4s) – pBtag-pD-p)2
417fb-1
m2miss = 0.04 GeV2
Select the lepton, reconstruct the D0 into several channels
Fit the signal yield into 10 w bins (ML fit)
2 fit to extract D2 and G(1)|Vcb| G(1) |Vcb| = (43.0 1.9 0.4) 10-3
2 = 1.20 0.09 0.04
B (B0D+-)= (2.170.06 0.07)% arXiv:0807.4978
DISCRETE 2008
Reconstruct the semileptonic decay D0K, K3 + soft (to make D*)+ lepton
Define the angle between the B and the D* candidate
Fit the signal yield
The decay rate depends on w, , V , Constraint pB pinclusive = pall –D*
140 fb-1
4D 2 fit to extract D*2, R1, R2 and F(1)|Vcb|
= 6.47
w = 0.025 cosv= 0.052
cos =0.047
F(1) |Vcb| = (34.4 0.2 1.0) 10-
32 = 1.293 0.045 0.029
B (B0D*+-) = (4.420.03 0.25)%
R1= 1.495 0.050 0.062
R2= 0.844 0.034 0.019
preliminary
DISCRETE 2008 A. Oyanguren 7
Reconstruct D0 and D+ candidates (D0K-+, D+K-++)
Use p*, p*
D and cosB-D to separate
BD and BD* decays
3D 2 fit to the yields to extract the form factor slopes, D and D* and BD and BD* BRs (R1 and R2 fixed).
D
D*
F(1) |Vcb| = (35.7 0.2 1.2) 10-3
D*2 = 1.21 0.02 0.07
B(B-D*0-)= (5.370.02 0.21)%
G1) |Vcb| = (43.8 0.8 2.3) 10-3
D2 = 1.22 0.04 0.07
B (B-D0-)= (2.360.03 0.12)%
207fb-1
preliminary
arXiv:0809.0828
1.5 2 1 1.5 2-2 -1 0 1
8
G(1)|Vcb| = (42.4 1.56) x 10-3
F(1)|Vcb| = (35.41 0.52) x 10-3
using G(1) =1.074 0.024
using F(1) =0.921 0.024
|Vcb| = (39.5 1.5exp 0.9latt ) x 10-3
|Vcb| = (38.4 0.6exp 0.9latt) x 10-3
Exp: - waiting Belle update - systematics tracking eff, radiative corrections, D**
- systematics tracking eff, D**
2/dof =39/21
2/dof =1.2/8
9
B-D*+--
B-D+--
B0D*0+-
B0D0+-
Ground Ground statesstates
Broad Broad statesstates
Narrow Narrow statesstates
9
??D
D*
D**
HQET
605 fb-1
417 fb-1
Theory predicts B(D1*,D2*) >> B(D*0,D1’), Experiments see B (D1*,D2*) <~ B(D0*,D1’)
Belle does not see the D1’, BaBar does.
Fully reconstructed analyses
B(B0Xc) > B(B0D) + B(B0D*) + B(B0D**) [10.1 0.4]% > [2.17 0.12]% + [5.16 0.11]% + [1-2]%
PRD77,091503(2008)
arXiv:0808.0528
DISCRETE 2008 A. Oyanguren 10
f(parameters related with b quark properties inside the hadron) kinetic energy, spin...
x=
Measurement of moments:
Some inclusive observables O depend on the same parameters
(For instance: BBXXcc : the lepton energythe lepton energy, the mass distributionthe mass distribution,
Vcb
Operator Product Expansion (OPE):
BBXXss : the photon spectrumthe photon spectrum)
DISCRETE 2008 A. Oyanguren 11
One B fully reconstructed into hadrons (Btag)
< Mxn> measured as function of p* cut
(from 0.8 to 1.9 GeV/c)
210fb-1
140fb-1
Rest of particles measure mx
< Een> measured as function of p*e cut
(from 0.4 to 2. GeV/c)
Event by event calibration Unfolded with SVD algorithm
< Mxn> for n=1,2,3,4,5,6 < Ee
n> for n=0,1,2,3,4
e+
arXiv:0707.2670
PRD 75, 032001(2007)
DISCRETE 2008 A. Oyanguren 12
605fb-1
< En> for n=1,2
< En> measured as function of
E cut (from 1.7 to 2.1 GeV)
Off-peak subtraction, veto to photons from 0 and
Select high energy photons (E*> 1.4 GeV)
Unfolded with SVD algorithm
t
W+
b S
PRD 78, 032016(2008)
DISCRETE 2008 A. Oyanguren 13
Using 27 moments from BaBar27 moments from BaBar, 25 moments from Belle 25 moments from Belle and 12 moments from other experiments (http://www.slac.stanford.edu/xorg/hfag/semi/ichep08/gbl_fits/kinetic/)
|Vcb| =(41.67 0.43fit 0.08 B 0.58th) x 10-3
mb =(4.601 0.034) GeV
2 =(0.440 0.040) GeV2
|Vcb| = (38.4 0.6exp 0.9latt) x 10-3 (Exclusive (BD*): |Vcb|incl - |Vcb|excl : 2.5
DISCRETE 2008 14
’
Untagged (high stat., most precise) Tagged (hadron or semileptonic)
Analysis methods:
(BR ~ 0.01% + large b c bkg)
reconstruction from full event (p = pbeams - pi)
Fit E = EB – s /2 and mES = s/4-|p*B|2
to extract the signal yield 206fb-1
q2= (pB - p )2 in 12 bins Form factor fit
B (B0-)= (1.460.07 0.08)x10-4
PRL 98, 091801(2007)
DISCRETE 2008 A. Oyanguren 15
One B decaying into B D(*) (Btag) Other lepton (-q) from the other B Define the systems Y=D(*) and X=
Fit to cos2B in 3 q2 bins
pD(*) p
B
pB
348fb-1
0805.2408 [hep-ex]
B+0B0-
signal signal
B (B0-)= (1.540.17 0.09)x10-4
Reconstruct the missing mass: m2
miss = (p(4s) – pBtag-p-p)2
Select the lepton from the other B select the ( rec. or into pions)
Reconstruct one B into hadrons (Btag)
B (B0-)= (1.120.18 0.05)x10-4
Extract yields in 3 q2 bins
(hadronic tag)(sl tag)
605fb-1
B (B+0)= (0.660.12 0.03)x10-4
DISCRETE 2008 A. Oyanguren 16
B (B0-)= (1.340.06 0.05)x10-4
(Untagged analysis can measure the form factor from data)
Form factor necessary to extract |Vub| theory
Models depend on q2 region:
PRL 98, 091801(2007)
DISCRETE 2008 A. Oyanguren 17
Check theoretical calculations Composition of BXu
347fb-1
605fb-1348fb-1
signal
untagged
hadron tag sl tag:
B (B0-)= (2.800.18 0.16)x10-4
0805.2408 [hep-ex]
0808.3524 [hep-ex]
A. Oyanguren 18
BBXX = = BBXXcc + + BBXXuu 5050 : : 11
Use kinematic variables to suppress as much as possible b c (keeping reliable theoretical calculations):
Theory needs low momentum cuts to extract|Vub| (OPE breaks down in the Shape Function (SF) region: low mx
2 and q2) OPE parameteres (mb, 2
) from moments in BXc and BXs
Experiments need high momentum cuts to suppress b c bkg
E, q2, mX and P+ = EX -|pX|
Tagged (sl or hadronic) or untagged
Experimental technique:
DISCRETE 2008
Measure partial BR
Select regions below charm threshold Key: bkg subtraction (off-peak data, endpoint, MC… ) bc bkg constrained by data in the low energy region
bkg
signal
Shmax=f(E, q2) = maximum mx squared
81fb-1
27fb-1 PR73:012006,2006.81fb-1
bc (MC)signal
signal
One B fully reconstructed Access to all kinematics (mx, q2, P+) for the signal side
(new Belle multivariate analysis no hard cuts, 90% PS)
604fb-1
PRL95:111801(2005)
PRB601:28(2005)
347fb-1
arXiv:0708.3702
1.55 GeV0.66 GeV
8 GeV2
signalsignal
bkg bkg
~40-
60%
acc
epta
nce
2020
Relating the rate to bs to reduce model dependence (LLR method)
PRL96:221801(2006)
80fb-1
mx cut =1.67
mx cut (GeV/c2)
arXiv:0801.2985
Moments of the full mass spectrum
220fb-1
unfolded
OPE fit to extract mb, 2 and .
B Xs B Xu
B Xc
mb =(4.604 0.250) GeV
2 =(0.398 0.240) GeV2
DISCRETE 2008 A. Oyanguren 21
OPE based + SF‣BLNP: HQE with systematic introduction of SFPRD71:073006 (2005)‣BLL: phase space in mx-q2 with reduced SFPRD64:113004 (2001)‣GGOU: kinetic schemeJHEP 10(2007) 058‣LNP (LLR): b→s directly related to b→ uνJHEP 0510:084 ( PLB 486:86 )
No SF introduced (model non-perturbative QCD)‣DGE: Dressed Gluon ExponentiationJHEP 0601:097 (2006)‣ADFR: Analytic couplingPRD74:03400(4,5,6) (2006) Vub excl
Vub incl
More data, more SP + improvements from theory needed
|Vub|from =(3.44 0.16)10-3
DISCRETE 2008
22
B- - , / K*b u,c,t
u
d/s
Inclusive
B → Xs
B → Xd
Exclusive
0.6 < MXd/s < 1.0 GeV
(Sum of all channels)
Form factors
veto to photons from 0 and
Select high energy photons
remove bkg from continuum
Yield from E = EB – s /2
and mES = s/4-|p*B|2
arXiv:0804.4770
PRL101:111801,2008
1st error exp., 2nd theo.
(error from fBsBBs / fBdBBd )
DISCRETE 2008 A. Oyanguren 23
Vud/Vud ~ 0.03%
Vus/Vus~ 0.4%
Vub/Vub~ 8%
Vcd/Vcd~ 5%
Vcs/Vcs~ 11%
Vcb/Vcb~ 2%
(Vtd/Vts)/(Vtd/Vts)~ 3%
Vtb/Vtb~ 15%
charm sl decays
decays Decays (0+0+)
The CKM matrix:The CKM matrix:
(excl . vs incl. ??)(excl . vs incl. ??)Need theory improvements Need theory improvements
DISCRETE 2008 A. Oyanguren 24
HFAG
DISCRETE 2008 A. Oyanguren 25
HFAG