Beyond the Standard Model: the clue from charm ...

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Beyond the Standard Modelthe clue from charm
...

• Precision study of b and c decays
• deviations in expected behaviour of
• b and c quarks evidence for new physics
• will elucidate new physics if found
  elsewhere
• Rare decays
• Mixing CPV

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• To use the full power of b and c decays,
  theoretical calculations of strong interactions
  must be used.
• The lattice gauge approach promises precision
  calculations that must be confronted with data
• Precision measurements of the D and Ds decay
  constants
• Semileptonic charm decay measurements Vcd
  and Vcs directly as well as input on hadronic
  matrix element

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Direct signatures for new physics in charm
decays
Bigi-Sanda hep-ph/9909479 A priori it is quite
conceivable that qualitatively different
forces drive the decays of up-type and down-type
quarks . More specifically, non-Standard-Model
forces might exhibit a very different pattern for
the two classes of quarks.
Charm decays are the only up-type quarks that
allow to probe this physicsnon-strange light
flavour hadrons do not allow for oscillations and
top-flavoured hadrons do not even form in a
practical way
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Mixing CPV
Motivation suppressed in the charm sector in
the SM. If measured, would suggest SM
extention
BaBar measurement is _at_ 57.1 fb-1
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• New limits expected by BaBar and Belle
• Cleo-c
  _at_ 95 C.L.
• CP violation
• Direct CP violation in D0 and D
• Indirect CP violation in D0 decays
• CP violation measurements exploiting the quantum
  coherence of the D0 D0bar produced pair
• y(3770) ? DD JP1-
• CP violation asymmetry sensitivity
• ACPlt0.01 _at_ Cleo-c and Beauty Factories

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Rare decays
Motivation lepton number violation
study investigation of long range effects and SM
extention
FOCUS improved results by a factor of 1.7 14
approaching theoretical predictions for some of
the modes but still far for the majority
CDF Br(D0?mm-)lt2.4 x10-6 _at_ 90 C.L. is the best
limit for this mode (65 pb-1 data)
CDF and D0 can trigger on dimuons ?promising
Cleo-c sensitivity 10-6
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Leptonic decays
Motivations decay constants measurements
Lattice predicts fB/fD fBs/fDs with small errors
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Hadronic and semileptonic decays

• Over constrain the Unitarity Triangle
• Inconsistencies New Physics

semileptonic decays are the easiest way to
determine CKM elementsQCD effects contained in
form factors. Comparison with LGT and quark
model calculations!
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Status of CKM Matrix
Current VCKM From direct Measurements -no
unitarity imposed
CLEO-c will redefine 2nd generation elements And
enable improvements in 3rd generation
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Potential Impact on VCKM
Current VCKM From direct Measurements -no
unitarity imposed
CLEO-c will redefine 2nd generation elements And
enable improvements in 3rd generation
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Summary of reach