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Present status of Charm Measurements. Arantza Oyanguren. ( IFIC –Valencia). Outline :. Introduction Charm fragmentation Leptonic decays Semileptonic decays Mixing and CP violation Rare and forbidden decays Hadronic decays. Introduction : why charm ?. - PowerPoint PPT Presentation
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Present status of Present status of CharmCharm
MeasurementsMeasurements
Arantza Oyanguren Arantza Oyanguren ((IFIC –Valencia)IFIC –Valencia)
Outline:Outline:
IntroductionIntroduction Charm fragmentationCharm fragmentation Leptonic decays Leptonic decays Semileptonic decaysSemileptonic decays Mixing and CP violationMixing and CP violation Rare and forbidden decaysRare and forbidden decays Hadronic decaysHadronic decays
Introduction: why charm?Introduction: why charm?Introduction: why charm?Introduction: why charm?
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 33
Vcd
The aim: The aim: find NEW PHYSICS find NEW PHYSICS The role of charm:The role of charm:
1) Overconstraining the UT
Understand the strong interaction:Hadronic effects in leptonic and semileptonic decays, fragmentation, hadronic decays
Help for inputs in B decays (more sensitive to NP) validating LQCD computations
Search for New Physics in Mixing and CP violation, rare and forbidden decays
2) Specific processes with c-hadrons
Charm LandscapeCharm LandscapeCharm LandscapeCharm Landscape
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 44
B-Factories e+e-
(4S)
Charm-”Factories” e+e-(3770)
Hadronic production
BABARBABAR
BELLEBELLE
CLEO-cCLEO-c
BESIIIBESIII
FOCUSFOCUSLHCbLHCbATLAS ATLAS CMS CMS
Charm Data SamplesCharm Data SamplesCharm Data SamplesCharm Data Samples
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 55
0.818 fb-1 @ (3770) ~ 106 D+D- pairs
0.586 fb-1 @ (4170) ~ 106 D*
sDs pairs
BESIII:~ 1 fb-1 @ (3770)( 10fb-1 in 6 years ?)
CLEO-c:
cc ~1.3 nb(4S) (4S)
BELLE:
Physics at charm threshold: (DD)
Physics at (4S) : (BB threshold)
711 fb-1 @ (4S) BaBar: 433 fb-1 @ (4S)
Clean environment: - less background- easy to recontruct all decay products
More statistics ~109 D(s)(*)(**)
More background
DD ~ 6nb
Fragmentation: access to D*, D**, Ds, c, etc…
(530 fb-1)
(1000 fb-1)
Charm FragmentationCharm FragmentationCharm FragmentationCharm Fragmentation
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 66
@ the (4S) the c quark hadronizes into D, D*, D**, Ds , baryons…
Their fractions and energetic distributions give infos for the CKM picture
(Ex: D** fractions enter as systematic uncertainties for Vcb, Vub…)
pD*/pbeam
D* fragmentation
Present Status:
- Old measurements from Belle and CLEO-III (BaBar on the way)
-Would like to have all (D, D*, D**, Ds, c, etc…) fragmentation functions
- Important to separate perturbative and non-perturbative parts
The charm fragmentation:- Provide reference data on decay properties- Help in the understanding of the QCD processes (test of models)
JHEP04(2009)082
(103 fb-1)(6 fb-1)
Leptonic Decays:Leptonic Decays:Leptonic Decays:Leptonic Decays:
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 77
Vcd
SM: D= 2.35 x 10-5 : 1: 2.65 (e::)
@ charm threshold:
’’
D+
D-
+K+
-
+
Tag-side:- full reconstruction
- Missing mass squared: Signal-side:
Measurement of decay constants: fD, fDs
fD(s) provides Lattice-QCD validation
CLEO-cCLEO-c
Leptonic Decays:Leptonic Decays:Leptonic Decays:Leptonic Decays:@ B-factories:
cc
D*s-
D
K
+
- Ds (Ds*Ds) reconstruction from all the event including fragmentation particles
521 fb-1
Present Status: - Good agreement between lattice and experiments on fD, not so good (2) on fDs.
- Lattice quite precise.
Ds-
X
- Reconstructed mass:
mr2(DKX
)
arXiv: 1008.4080
CLEO-c () (‘09)
258(11) CLEO-c () (‘09)260(9)
275(20) BELLE () (‘07)
BaBar () (‘10)
Exp. Average (CKM ‘10)
259(10)
260(5)
241(3)
260 (10)
248 (3)
Lattice HPQCD+UKQCD (‘08)
Lattice FNAL+ MILC (‘09)
Lattice HPQCD (‘10)
fDs (MeV)
248 (9) Lattice ETMC (‘10)
207(9)
207 (4)
217(10)
205(10)
fD
Lattice FNAL+ MILC (‘09)
Lattice HPQCD+UKQCD (‘08)
CLEO-c
(MeV)
Lattice ETMC (‘10)
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 88
Semileptonic DecaysSemileptonic DecaysSemileptonic DecaysSemileptonic Decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 99
Measurement of form factors f+(q2):
Vcs, Vcd
hadronic effects parameterized by form factors f(q2)
q2=(p+p)2=(pD-px)2
@ charm threshold: -Full reconstruction in the tag side- pion + lepton in the signal side- U = Emiss – |pmiss|
good signal/bkg separation good q2 resolution
CLEO-c
818 pb-1
1) Pseudoscalar: 1 form factor; DP (P=K,)2) Vectorial: 3 form factors; D(s)V (V=K*, ,)
1) D(K or )
’’
D0
D0
-
K+
e+
e -
PRD 80 032005 (‘09)
Present Status:
- Precise measurements of DK and D form factors (BaBar, CLEO-c)
Semileptonic DecaysSemileptonic DecaysSemileptonic DecaysSemileptonic Decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1010
@ B-factories:
FNAL/MILC
Preliminary
D
DK
(4S) rest frame
- Partial reconstruction (D* tag) @ BaBar and full reconstraction @ Belle (CLEO-c like) DD00KK--++
DD00KK--++
- New results from CLEO-c on D form factor
- New precise results from Lattice agree with experiment
PRD 76 (2007) 052005
Lattice 2010
Semileptonic DecaysSemileptonic DecaysSemileptonic DecaysSemileptonic Decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1111
2) Ds
First evidence of a S-wave component:
70% peaking ()
asymmetryasymmetry
@ charm threshold:@ B factories : DsKKe
Interference with
d depends on q2, v , l , and 2 form factor ratios: rV and rA
-Partial reconstruction method -Also visible the 0+: f0 (980) - Full reconstruction method
K+K-
PRD78 (2008) 051101 (RC)
CLEO-c
PRD 80 (2009) 052009
600 pb-1
214 fb-1
Semileptonic DecaysSemileptonic DecaysSemileptonic DecaysSemileptonic Decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1212
2) DK* @ charm threshold:
@ B factories : DKe
d depends on m, q2, v , l , and 2 form factor ratios: rV and r2
-Also measure the suppressed decay De ()
- Full reconstruction method
Also measures the phase of the K S-wave:
Preliminary
Preliminary
Semileptonic DecaysSemileptonic DecaysSemileptonic DecaysSemileptonic Decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1313
Present Status:
- Accurate measurements of form factors: DK*Ds
D
0.83 0.15
1.48 0.12
CLEO-c
BaBar BaBar
Comparison with LQCD:
- Lattice lacks precision:
Ds
DK*
Preliminary
Mixing and CP ViolationMixing and CP ViolationMixing and CP ViolationMixing and CP Violation
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1414
Charm mixing: mass and flavor eigenstates are different
The mixing is measured with two parameters: x and y
x=(m1-m2)/
y=(1-2)/2(with =(1+ 2)/2 )
CP Violation in the SM occurs at per mil level and could be found:
In the SM |x| and |y| <10-2
- In the decay (direct)
- In mixing (indirect)
- In the interference between mixing and decay
Weak phase:
468.5 fb-1
Mixing and CP ViolationMixing and CP ViolationMixing and CP ViolationMixing and CP Violation
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1515
First evidence for D0-D0 mixing
Phys.Rev.Lett.98(2007)211802
Wrong sign D0K+- decays:
Amplitude analysis of D0(t) Ks h+h-
(New and most precise result to date)
RS/WS ratio as function of time, extract rotated mixing parameters (x’2, y’).
Mix
ing
ev
ide
nc
e @
3.9
Average decay time as function of Dalitz-plot position allows to get the mixing parameters x and y
@ B factories:
Time dependent mesurements:
- Select D0 mesons from D*+D0+ (tags flavour)- m=mD*+ - mD0 to supress bkg.- Measure the decay time (t ~ 0.2 ps)
384 fb-1
Present Status:
Mixing and CP ViolationMixing and CP ViolationMixing and CP ViolationMixing and CP Violation
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1616
- No CPV point within 1
- Mixing established at 10.2
No mixing point
No CPV point
- Many experimental results:
- SM predictions difficult due to non-perturbative (long-distance) contributions…
?
Present Status:
Rare and forbidden decaysRare and forbidden decaysRare and forbidden decaysRare and forbidden decays
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1717
- Some present results and projections (BESIII with 20fb-1)
Lepton decays (D0+-), GIM suppressed decays (DMeson +-), decays violating Lepton Flavour (De) or Lepton Number (D+Meson ++) Very suppressed (B < 10-6), ultra-suppressed or forbidden in the SM New Physics could enhance the rates through virtual non-standard particles
SummarySummarySummarySummary
Arantza OyangurenArantza OyangurenVII Meeting on B PhysicsVII Meeting on B Physics 1818
Measurements in the charm sector are important for the CKM picture control of hadronic effects, validation of Lattice QCDIt can also give signs of New Physics
Leptonic decays: theory and experiment agree on D, not so well on Ds (2)Some results from LQCD more accurate than experiment (BESIII?)
Semileptonic decays:Experimental results from B-Factories and CLEO-c agreeTheory lacks precision (LQCD for sl decays improving…)
Charm mixing:
Rare decays:
Charm mixing established, need to separate x and y. No CPV at present.What does the SM say?
Sensitivity ~10-6 at CLEO-c, waiting BESIII (~10-8 with 20fb-1) and/or SuperB