Extract the partial rates We can make fits to the partial decay rates to extract
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We can make fits to the partial decay rates to extract (1) normalization f + (0)|V cx | (2) Form factor shape parameters r 1 and r 2 (or just r 1 ) for series M pole for simple pole α for modified pole r for ISGWII fast atrest Assuming |V cd |= 0.22560.0010 (CKM unitarity) 1 σ bands (stat and syst) by FNAL- MILC-HPQCD Introduction Fits to the U Distributions D Tagging at 3770 MeV Summary Form factors as a stringent test of LQCD |V cs | and |V cd | Results Bo Xin, Ian Shipsey, Purdue University, CLEO Collaboration Improved measurements of D meson semileptonic decays to π and K mesons Goals of CLEO-c semileptonic decay analysis program To provide validation and calibration data for LQCD and other theoretical approaches thereby enabling theory (especially LQCD) to be applied to B physics (|V ub |). To measure |V cs | and |V cd | with a validated theory We have perform an analysis using CLEO-c’s final data set to meet these goals Most precise branching fraction determinations for D Ke + and D πe + Stringent test of LQCD calculations of semileptonic form factors. D Ke + , D πe + form factors are found to be in general agreement with LQCD. Best direct measurement of |V cs |, measured to ±1.1% (experimental) ± 10%(theory). |V cd | is measured to ±3.1%(experimental) ± 10%(theory). DK/πe + Branching fractions Standard D Tags (Tag): One D in the event is fully reconstructed in a hadronic decay mode, the second D decays semileptonically 0 0 0 0 (3770) , D D D D K e K The three charge +2/3 quarks and three charge -1/3 quarks change identity via the weak interaction with a probability proportional to the elements of the 3x3 unitary Cabibbo-Kobayashi-Maskawa matrix. These nine elements are related to four fundamental parameters of the standard model of particle physics and must be determined by experiment. Semileptonic decays are the principal process for measuring the CKM matrix elements Strong interaction effects are confined to the hadronic current and are parameterized by form factors in massless lepton limit For P to P transitions The theory must predict the absolute normalization of the form factors: As |V cd | and |V cs | are tightly constrained by the unitarity of the CKM matrix. Measurements of charm semileptonic decay rates and form factors rigorously test the theory (e.g. LQCD) Validated theory can then be applied to B decays to determine |V ub |, which is the one of the most poorly known CKM matrix elements from fits to M bc tag tag j j ij D D i i N N BF / 1 1 from fits to U 2 2 3 3 ) ( 2 ) ( 2 2 ) ( 24 ) ) ( ( q f P V G dq e K D d K cd cs F Pure DD, zero additional particles, ~5-6 charged particles per event ~6.6x 10 5 D 0 and ~4.8 x 10 5 D + tags reconstructed from ~5.4 x 10 6 DD events We tag ~20% of the events, compared to ~0.1% of B’s at the Y(4S) 2 2 4 2 /c p /c E M D beam bc 818 pb -1 @3770 (full data set) World’s largest data set at 3.770 GeV (ρ, η) ~| V ub | Δm d,s l B 2 2 2 [ ( )] | | B ub rate f q V l (K) D 2 ) ( 2 2 ) ( | | )] ( [ s cd K D V q f rate HQS Suffer from large theory uncertainty Moriond 09 We perform binned likelihood fits to U distributions in each q 2 bin and tag mode Signal shapes are taken from signal MC, smeared with double Gaussians Background shapes are taken from MC with all DD and non-DD decays 4 of 27 U fits 0 e D Ke S/N ~300/1 Signal events ~14000 U resolution ~10 MeV q 2 resolution ~0.008 GeV 2 /c 4 0 e D e 4 of 54 U fits 0 e D e 0 e D e 0 e D Ke 4 of 42 U fits 4 of 21 U fits S/N ~40/1 Signal events ~1400 U resolution ~10 MeV q 2 resolution ~0.008 GeV 2 /c 4 0 e D Ke For semileptonic D : U peaks at zero for real semileptonic decays An absolute measurement, independent of the integrated luminosity and number of D mesons in the data sample | | miss miss P E U Precision measurements from BABAR/Belle/CLEO- c. CLEO-c most precise. Theoretical precision lags experiment. 0 2 B( ) 10 D K e 0 3 B( ) 10 D e (( ))/ ( )~1.4% (( ))/ ( )~3.0% B Ke B Ke B e B e 1 3.50(3)(4)% (C LEO -c 818 pb ) 1 0.288(8)(3)% (C LEO -c 818 pb ) 1 σ bands (stat and syst) by FNAL-MILC- HPQCD ( ) ( ) 2 2 2 2 2 (0) ( ) 1 1 pole pole f q q m f q m Modified pole model used to compare with LQCD Shape: ( ) Ke K + Norm alization: f (0) 0 (BA BA R m easures relativeto ) D K K fast Form factor measures probability hadron will be formed 0.39(2) m y average (Fitto CLEO , Belle & BaBar) K Assuming |V cs | =0.973340.00023 (CKM unitarity) α : CLEO-c prefers smaller value for shape parameter than other experiments f + (0): experiments (1.2%) consistent with LQCD (10%) CLEO-c is most precise. Theoretical precision lags. tag tag K atrest shape: ( ) e 0.22(4) m y average (Fitto CLEO & Belle) tag tag α : CLEO-c measurements are compatible with LQCD f + (0): experiments (2.9%) consistent with LQCD (10%). CLEO-c is most precise. Theoretical precision lags. 0 e D e 0 e D Ke arXiv:0906.2 983 (accepted PRD Jul 22 2009) arXiv:0906.29 83 (accepted PRD Jul 22 2009) CLEO-c: the most precise direct determination of |V cs | 1 (818 pb ) 0.985 0.009 0.006 | | stat syst theor 0.103 y cs CLEO c V * 1 (818 pb ) 0.234 0.007 0.0 | | stat syst t 02 0.0 heor 25 y cd CLEO c V CLEO-c: νN remains most precise determination N cd cd (V )/V ~3.1% (expt) 10% (theory) cs cs (V )/V ~1.1% (expt) 10%(theory) * PDG2002 The data determine |V cs(d) |f + (0). To extract |V cs(d) |, we combine the measured |V cs(d) |f + (0) values using the Becher-Hill parameterization with (FNAL-MILC-HPQCD) for f + (0) * N * PDG2002 THEORY UNCERTAINITY REMOVED * PDG2002 * The uncertainties on our results are dominated by uncertainties from LQCD Theoretical precision lags. In particular, CLEO-c measures form factor normalizations for D Ke + , D πe + to 1% and 3%, respectively, while LQCD predicts them at 10% level. We are eagerly awaiting more precise LQCD calculations of semileptonic form factors CLEO-c Now CLEO-c full data set + 3-4% theory uncertainties Plots by Sebastien Descortes-Genon & Ian Shipsey See also talk by Descotres-Genon at joint BABAR-Belle-BESIII-CLEO-c Workshop 11/07,
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l. l. B. n. n. p. p(K). Improved measurements of D meson semileptonic decays to π and K mesons. CLEO-c Now. CLEO-c full data set + 3-4% theory uncertainties. ( ρ , η ). Δ m d,s. ~| V ub |. Bo Xin , Ian Shipsey , Purdue University, CLEO Collaboration. Introduction. - PowerPoint PPT Presentation
Transcript of Extract the partial rates We can make fits to the partial decay rates to extract
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Extract the partial rates
We can make fits to the partial decay rates
to extract (1) normalization f+ (0)|Vcx|(2) Form factor shape parameters r1 and r2 (or just r1) for series
Mpole for simple pole
for modified pole
r for ISGWII
Assuming |Vcd |= 0.22560.0010 (CKM unitarity)1 bands (stat and syst) by FNAL-MILC-HPQCD
IntroductionFits to the U DistributionsD Tagging at 3770 MeVSummaryForm factors as a stringent test of LQCD|Vcs | and |Vcd | Results Bo Xin, Ian Shipsey, Purdue University, CLEO Collaboration
Improved measurements of D meson semileptonic decays to and K mesons
Goals of CLEO-c semileptonic decay analysis program To provide validation and calibration data for LQCD and other theoretical approaches thereby enabling theory (especially LQCD) to be applied to B physics (|Vub|). To measure |Vcs| and |Vcd| with a validated theory We have perform an analysis using CLEO-cs final data set to meet these goalsMost precise branching fraction determinations for D Ke+ and D e+ Stringent test of LQCD calculations of semileptonic form factors. D Ke+, D e+ form factors are found to be in general agreement with LQCD.Best direct measurement of |Vcs|, measured to 1.1%(experimental) 10%(theory). |Vcd| is measured to 3.1%(experimental) 10%(theory). DK/e+ Branching fractions Standard D Tags (Tag): One D in the event is fully reconstructed in a hadronic decay mode, the second D decays semileptonically
The three charge +2/3 quarks and three charge -1/3 quarks change identity via the weak interaction with a probability proportional to the elements of the 3x3 unitary Cabibbo-Kobayashi-Maskawa matrix. These nine elements are related to four fundamental parameters of the standard model of particle physics and must be determined by experiment. Semileptonic decays are the principal process for measuring the CKM matrix elementsStrong interaction effects are confined to the hadronic current and are parameterized by form factors in massless lepton limitFor P to P transitionsThe theory must predict the absolute normalization of the form factors:
As |Vcd| and |Vcs| are tightly constrained by the unitarity of the CKM matrix. Measurements of charm semileptonic decay rates and form factors rigorously test the theory (e.g. LQCD)Validated theory can then be applied to B decays to determine |Vub|, which is the one of the most poorly known CKM matrix elements
from fits to Mbc
from fits to U
Pure DD,zero additional particles, ~5-6 charged particles per event
~6.6x 105 D0 and~4.8 x 105 D+ tagsreconstructed from~5.4 x 106 DD events
We tag ~20% of the events, compared to ~0.1% of Bs at the Y(4S)
818 pb-1 @3770 (full data set)Worlds largest data set at 3.770 GeV
(, )~|Vub|md,slnBp
lnp(K)D
HQSSuffer from large theory uncertaintyMoriond 09We perform binned likelihood fits to U distributions in each q2 bin and tag modeSignal shapes are taken from signal MC, smeared with double GaussiansBackground shapes are taken from MC with all DD and non-DD decays
4 of 27 U fits
S/N~300/1Signal events~14000U resolution~10 MeVq2 resolution~0.008 GeV2/c4
4 of 54 U fits
4 of 42 U fits4 of 21 U fitsS/N~40/1Signal events~1400U resolution~10 MeVq2 resolution~0.008 GeV2/c4
For semileptonic D : U peaks at zero for real semileptonic decaysAn absolute measurement, independent of the integrated luminosity and number of D mesons in the data sample
Precision measurements from BABAR/Belle/CLEO-c. CLEO-c most precise. Theoretical precision lags experiment.
1 bands (stat and syst) by FNAL-MILC-HPQCD
Modified pole model used to compare with LQCD
Form factor measures probability hadron will be formed
Assuming |Vcs |=0.973340.00023 (CKM unitarity) : CLEO-c prefers smaller value for shape parameter than other experimentsf+ (0): experiments (1.2%) consistent with LQCD (10%) CLEO-c is most precise. Theoretical precision lags.
: CLEO-c measurements are compatible with LQCDf+ (0): experiments (2.9%) consistent with LQCD (10%). CLEO-c is most precise. Theoretical precision lags.
arXiv:0906.2983 (accepted PRD Jul 22 2009)arXiv:0906.2983 (accepted PRD Jul 22 2009)
CLEO-c: the most precise direct determination of |Vcs |
*
CLEO-c: N remains most precise determination
* PDG2002The data determine |Vcs(d)|f+(0). To extract |Vcs(d)|, we combine the measured |Vcs(d)|f+(0) values using the Becher-Hill parameterization with (FNAL-MILC-HPQCD) for f+(0)
*
* PDG2002THEORY UNCERTAINITY REMOVED* PDG2002*The uncertainties on our results are dominated by uncertainties from LQCD Theoretical precision lags. In particular,CLEO-c measures form factor normalizations for D Ke+, D e+ to 1% and 3%, respectively, while LQCD predicts them at 10% level.
We are eagerly awaiting more precise LQCD calculations of semileptonic form factors
CLEO-c NowCLEO-c full dataset + 3-4% theoryuncertaintiesPlots by Sebastien Descortes-Genon & Ian ShipseySee also talk by Descotres-Genon at joint BABAR-Belle-BESIII-CLEO-c Workshop 11/07, Beijing
