7/4/08 Flavour physics at CLEO-c - Jim Libby 1 Jim Libby (University of Oxford) On behalf of the...
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7/4/08 Flavour physics at CLEO-c - J im Libby 1 Jim Libby (University of Oxford) Jim Libby (University of Oxford) On behalf of the CLEO-c collaboration On behalf of the CLEO-c collaboration Introduction to CLEO-c Measurements related to D-mixing Measurements related to the determination of via B ± DK ± D→K − π + π + π − D→K 0 S π + π − Flavour physics at CLEO-c
7/4/08 Flavour physics at CLEO-c - Jim Libby 1 Jim Libby (University of Oxford) On behalf of the CLEO-c collaboration Introduction to CLEO-c Measurements
Text of 7/4/08 Flavour physics at CLEO-c - Jim Libby 1 Jim Libby (University of Oxford) On behalf of the...
Slide 1
7/4/08 Flavour physics at CLEO-c - Jim Libby 1 Jim Libby
(University of Oxford) On behalf of the CLEO-c collaboration
Introduction to CLEO-c Measurements related to D-mixing
Measurements related to the determination of via B DK DK + + DK 0 S
+ Flavour physics at CLEO-c
Slide 2
7/4/08 Flavour physics at CLEO-c - Jim Libby 2 Detector at the
Cornell Electron Storage Ring (CESR) Operating at energies around
cc threshold Relevant data sets for flavour measurements: E CM =
4170 MeV L int ~ 600 pb -1 Determination of form factor f Ds at
CLEO-c is a critical test of lattice QCD and sensitive to new
physics ( 3770 ) L int = 818 pb -1 [This talk] Quantum correlated
state: For example, reconstruct one D decay to a CP eigenstate
uniquely identifies the other D to be of opposite CP C = 1
Introduction to CLEO-c CLEO-c - arXiv:0712.1175v1 [hep-ex] f Ds
=(274 10 5) MeV LQCD - arXiv:0706.1726 [hep-lat] f Ds =(241 3)
MeV
Slide 3
7/4/08Flavour physics at CLEO-c - Jim Libby3 CLEO-c results on
D-mixing
Slide 4
7/4/08 Flavour physics at CLEO-c - Jim Libby 4 D mixing Rate of
D mixing parameterised by: Time-dependent wrong-sign rate D 0 K + :
Sensitivity via interference between DCS and mixing amplitudes
Ambiguity from strong phase: y = y cos x sin Direct comparison with
y measurements from CP- eigenstate lifetimes and time-dependent
measurements of DK 0 S Dalitz plot not possible without
determination of and other mixing parameters can be measured in
quantum correlated DD decay at CLEO-c D. Asner and W. Sun, P hys.
Rev. D73, 034024 (2006) A DCS /A CF = / = re i
Slide 5
7/4/08 Flavour physics at CLEO-c - Jim Libby 5 Coherent vs.
Incoherent Decay We use yields for single tags (one D
reconstructed) double tags (D and D reconstructed) Compare
coherent/incoherent BFs Sources of incoherent BFs: Externally
measured BFs Single tags at (3770) DT KK e+e+ CP CP KK R M / R WS
KK 1 2R WS 4rcos (rcos y) ee 1 r (ycos xsin ) 1 CP 1 (2rcos y) / (1
R WS )1 y 0 CP 1 (2rcos y) / (1 R WS )1 y 20 ST 1111 QC rate
incoherent rate DD Xi DD ji Yield / No-QC prediction 012 Quantum
correlations are seen in data! ST DT R M = (x 2 + y 2 )/2 and R WS
= r 2 + ry + R M
Slide 6
7/4/08 Flavour physics at CLEO-c - Jim Libby 6 Yield
measurements in 281 pb 1 1.Fully-reconstructed single tags: Fit
beam-constrained mass distribution 2.Fully-reconstructed double
tags: Two fully-reconstructed STs 3.Inclusive semileptonic DTs: One
fully-reconstructed ST Plus one electron candidate Fit e momentum
spectrum 4.K 0 L 0 double tags: One fully-reconstructed ST Plus one
0 candidate Compute missing mass 2 Signal peaks at M 2 (K 0 ). 1 2
3 4 M BC ( GeV/c 2 ) e p ( GeV/c ) arXiv:0802.2264 [hep-ex]
arXiv:0802.2268 [hep-ex]
Slide 7
7/4/08 Flavour physics at CLEO-c - Jim Libby 7 External inputs
External inputs improve y and cos precision All correlations among
measurements included in fit Standard fit includes: Info on r
needed to obtain cos : R WS = r 2 + ry + R M R M = (x 2 + y 2 )/2
Assume xsin = 0 y ycos K and CP -eigenstate BFs Extended fit
averages y and y : CP+ lifetimes ( y ) K 0 S Dalitz analysis ( x, y
) K CP -conserving fits ( y, r 2, R M )
Slide 8
7/4/08 Flavour physics at CLEO-c - Jim Libby 8 Results First
determination Standard fit result important component in average of
charm mixing Extended fit leads to measurement of: Future
improvements: Full (3770) data set 818 pb 1 WS semileptonics vs. K
Additional K 0 L modes C -even information from 4170 MeV data
arXiv:0802.2264 [hep-ex] arXiv:0802.2268 [hep-ex] From likelihood
scan of physically allowed region
Slide 9
7/4/08Flavour physics at CLEO-c - Jim Libby9 CLEO-c results
related to determination
Slide 10
7/4/08 Flavour physics at CLEO-c - Jim Libby 10 Status of
direct determination of is the least well determined angle of the
unitarity triangle with an uncertainty of ~30 from direct
measurements = 1 Comparison of measurements of in tree and loop
processes sensitive to new physics Side opposite - B-mixing
measurements loop only
Slide 11
7/4/08 Flavour physics at CLEO-c - Jim Libby 11 from B DK
Extraction through interference between bc and bu transitions
Require decay of D 0 and D 0 to a common final state, f(D) A
theoretically clean determination of SM standard candle Colour/CKM
suppressed r B ~0.1
Slide 12
7/4/08 Flavour physics at CLEO-c - Jim Libby 12 f(D) = non-CP
Eigenstate (e.g. K + - ) (1)(1) (3)(3) (2)(2) (4)(4) From counting
these 4 rates, together with those from CP eigenstates ( KK, ), a
determination of can be made Key measurement of LHCb and future e +
e B-factories For example ~10 precision with one year of LHCb
running [LHCb-2008-011] Atwood-Dunietz-Soni (ADS) Method ~0.06
Slide 13
7/4/08 Flavour physics at CLEO-c - Jim Libby 13 Four-body ADS
BD(K)K can also be used for ADS style analysis Double the branching
fraction of BD(K)K However, need to account for the resonant
substructure DK*, K a 1 (1260) +, etc in principle each point in
the phase space has a different strong phase associated with it
Atwood and Soni (hep-ph/0304085) showed how to modify the usual ADS
equations for this case Introduce coherence parameter R K3 which
dilutes interference term sensitive to R K3 ranges from 1=coherent
(dominated by a single mode) to 0=incoherent (several significant
components)
Slide 14
7/4/08 Flavour physics at CLEO-c - Jim Libby 14 Determinations
of R K3 and D can be are made from analysis of double- tagged D 0 D
0 at CLEO-c. The coherent production of this state causes the
double-tagged rates of K vs. X to be altered in the following ways:
(R K3 ) 2 R K3 cos( K3 ) R K3 cos( K ) Double Tag Rate Sensitive To
We perform selections of these double-tags In addition, it is also
necessary to perform selections of the opposite sign K modes to
determine normalisation factors Measuring R at CLEO-c
Slide 15
7/4/08 Flavour physics at CLEO-c - Jim Libby 15 KK, K s 0 695 K
S ( + - 0 )251 K S K S )31 K S K S CP Tag 2,183 Yield Selections
performed over all ( 3770 ) data, corresponding to 818 pb -1.
Consider 8 different CP tags: Assess flat background from mass side
bands and peaking from MC: m bc 2 = (E beam ) 2 /c 4 (p D ) 2 /c 2
Very low background levels K3 Opp. Sign 3,921 events CP = 1, CP =
-1 Event selection
Slide 16
7/4/08 Flavour physics at CLEO-c - Jim Libby 16 2) (R K3 ) 2 =
-0.20 0.23 0.09 (R K3 at sigma) 1) = -0.60 0.19 0.24 /n.d.f = 9.7 /
8 3) : sigma spread : physically allowed region R K3 cos( K ) =
0.00 0.16 0.07 Used to constrain coherence factor by taking D from
TQCA CLEO-c Preliminary R preliminary results
Slide 17
7/4/08 Flavour physics at CLEO-c - Jim Libby 17 Parameter Space
Constraints Combination of the separate results together Low
coherence preferred Allows accurate determination of r B useful for
all B DK Preliminary
Slide 18
7/4/08 Flavour physics at CLEO-c - Jim Libby 18 Impact of
CLEO-c at LHCb These DK3 measurements have been input to ADS
simulation studies by LHCb Estimated yields documented in
LHCb-2006-066 and LHCb-2007-004 One nominal year of running results
see significant improvement with the addition of BD(K3)K and the
CLEO-c constraints
Slide 19
7/4/08 Flavour physics at CLEO-c - Jim Libby 19 3-Body Dalitz:
B D(K s + - )K Exploit interference over Dalitz space Amplitude fit
to D Dalitz plots from B+ and B- to extract r B, and B. Need to
assume an isobar model for D-decay amplitudes Measure amplitudes
well with flavour tag sample Current best constraints from the
B-Factories But model assumptions lead to a ~10 error Binned
analysis of Dalitz space removes model error Need to measure strong
phases averaged over bins at CLEO-c Most sensitive binning w.r.t.
strong phase diff.
Slide 20
7/4/08 Flavour physics at CLEO-c - Jim Libby 20 CLEO-c Impact
on B D(K s + - )K As in the coherence factor analysis, CP tagged
decays are the key to accessing the parameter of interest.
Specifically, the average value of cos( D ) in each bin of the CP
tagged Dalitz plot can be accessed from measuring the number of
events in that bin with different CP-tags Measurements of K s + vs.
K s + give sensitivity to sin( D ) Preliminary studies presented at
CHARM 07 indicate precisions that lead to 3-5 uncertainties on CLEO
Prelim. f 2 (1270
Slide 21
7/4/08 Flavour physics at CLEO-c - Jim Libby 21 First
determination of strong phase difference for DK Essential for
interpretation of D - mixing CLEO-c data vital for for the purpose
of extraction strategies with B D( Multi-Body )K A first
determination of the D K coherence factor, R K3 , has been made
(and its associated global strong phase, D ). Further improvements
to this result are foreseen with the addition of K L CP modes in
the selection. Additional ADS modes are being studied ( D K ). In
addition, CLEO-c is measuring the average cosine and sine of K s
strong phase differences to allow model independent determination
of with B D( K s )K Conclusion
Slide 22
7/4/08Flavour physics at CLEO-c - Jim Libby22 Backup
Slide 23
7/4/08 Flavour physics at CLEO-c - Jim Libby 23 TQCA extended
fit likelihoods