Transcript slides

Part I:
3-sigma anomaly of W->tau nu decay
in new physics beyond SM
----first clean hint of right-handed charge current?
(hep-ph/0504123)
朱守华（Shou-hua Zhu）
Peking University
July 2005 @ Tsinghua Univ.
•3-sigma anomaly of W->tau nu measurements
•Anomaly in 2HDM and MSSM
•Anomaly indicates right-handed charge current?
朱守华, 北京大学物理学院
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Two destinations of puzzles
1: Puzzles stand for new dynamics
•Speed of light as constant
•- puzzle
•Sun neutrino missing
2: Puzzles stand for ignorance (both theoretical and expt.)
•CDF di-jet
•Re() in K-system
•b-inclusive production
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•ADL final
•O prel.
Anomaly mainly
comes from L3
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3-sigma anomaly of W->tau measurements,
hep-ex/0412015
New physics?
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3-sigma anomaly of W->tau nu is especially
interesting and important:
•In SM involved is only pure left-handed
charge current
•Simpler kinematics and less hadronic
uncertainties.
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Possible explanations in new physics
beyond the SM:
•
•
•
•
Oblique-type corrections -> NO!
Flavor-dependent interaction!
Satisfy neutral-current data (Z-decay) at O(0.1%)
Satisfy tau-> nu_tau l nu_l data
•Tan(beta) enhancement flavor interactions
•Higgs-fermion Yukawa couplings in 2HDM
•Chargino(Neutrolino)-fermion couplings in MSSM
Positive!
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2-Higgs doublet model (2HDM)
Negative except for near-degenerate Higgs mass case:
Lebedev etal., PRD62(2000)055014
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MSSM
•Use FeynArts, FormCalc, LoopTools to scan parameter space
•In most cases, delta_new is negative
•In all cases
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Anomaly in 2HDM and MSSM
•It is hard to account for anomaly in two models.
•And it is even harder to account for both W anomaly
and neutral data.
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Anomalous left- and right-handed couplings
From W->tau nu_tau data:
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Constraints from tau-decay data
Delta_L and Delta_R are constrainted by Michel
parameters which can be extracted from energy
spectrum of daughter letopn in tau->nu_tau l nu_l.
PDG(2004)
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Allowed
small
regions at
95% CL
dR: 0-> 0.12
dL: 1-> 1.005
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Anomalous left- and right-handed couplings for
3rd generation quark :
From B->X_s gamma measurements:
Re(dR)< 4 10-3 for Wtb
F. Larios etal., PLB457 (1999)334
|dR| 0.12
for W
?
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Summary for 1st part (questions)
•Is W->tau nu_tau 3-sigma anomaly the first clean
signal for the existence of right-handed charge
current?
•How is this anomaly related to fermion mass
generation (flavor physics)?
•Will parity be restored at high energy?
•Does anomaly indicate the non-universality of
gauge interactions for different generation?
X.Y. Li and E. Ma, PRL47, 1788(1981)
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Part II:
Distinguishing Split from TeV
(normal) SUSY at ILC
hep-ph/0407072, PLB604,207(2004)
朱守华
Shou-hua Zhu
Peking University
July 2005@ Tsinghua Univ.
Outline
Why Split SUSY (SS)?
How to distinguish SS from TeV SUSY?
Chargino pair production at Linear
colliders
Summary
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Why Split SUSY? (I)
 Naturalness problem in the SM
mHphy= mH0 +c 2+…,  ---new physics scale
=> New Physics should appear at TeV
(TeV/ EW ~10)
 Solutions (TeV scale New Physics) to Naturalness
problem
TeV SUSY or little Higgs models
Low scale gravity
Composite Higgs boson etc.
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 TeV New Physics is an attracting thing
(important basis of future colliders),
but …
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Akani-Hamed,
Pheno2005
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S. Dawson, LP2005
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 TeV SUSY is a beautiful thing (GUT,
dark matter, aesthetic …), but …
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S. Dawson, LP2005
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 Shortcomings of TeV SUSY
not yet found Higgs  small hierarchy problem
(remind: in MSSM at LO mH<MZ)
 excess flavor and CP violation =>”CP problem”
 fast dim-5 proton decay etc.
 …

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 Seems MNew Physics >>TeV, did we miss
something important? Is that possible
that naturalness …?
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Why Split SUSY? (II)
 Failure of Naturalness of Cosmological
Constant ->…
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Akani-Hamed,
Pheno2005
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Fine tuning =>
 God
 mechanisms
Assuming UNKNOWN mechanism for
finely tuned CC is also applied to
Higgs sector…
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 GUT and Dark Matter instead of Naturalness are
guiding principles  Split Supersymmetry
N. Arkani-Hamed &S. Dimopoulos, hep-ph/0405159
 Split Supersymmetry can get
(a) GUT ( slightly improved)
(b) Dark Matter density
(c) higher Higgs mass (120~160 GeV)
(d) cures to most of TeV SUSY diseases etc.
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Akani-Hamed,
Pheno2005
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What is Split SUSY?
• SS has only one finely tuned and light Higgs
boson while other scalars are ultra heavy.
• Gaugino and Higgsino might be light.
• Effective Lagrangian at low energy, besides
kinetic terms, after integrating out higher
scalar mass:
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How to distinguish SS?
• Precisely measuring Higgsino-gaugino-Higgs
vertexes
e.g.
O(0.1 fb) hep-ph/0407108
• Scale of scalars is the most characteristic
feature of SS, but directly producing scalars
other than light Higgs boson is difficult.
• How to determine scalar mass?
(a) Long-lived gluino as a probe of scalar mass at
LHC
or
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Chargino production at LCs
(b) Chargino pair production at Linear colliders can
probe the properties of chargino S.Y. Choi et.al. (1999)
and (2000) and is sensitve to sneutrino mass.
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SS Parameter Space & Mixed Region
• Assuming gaugino mass
unification and dark
matter constraint:
0.094 <DMh2<0.129
G. Giudice & A. Romanino,
hep-ph/0406088
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Point Pa: Differential  and Forward-backward Asymmetry
(11)
10 TeV
1 TeV
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Point Pa: total 
(11), (12) and (22) are
all sensitive to sneutrino
mass up to 10 TeV for
lower M2 and .
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Point Pb: Total 
(22) Mode is most promising for higher
朱守华, 北京大学物理学院
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Summary for 2nd part
• Chargino pair production can probe the
sneutrino mass up to 10 TeV. Need further
simulation!
• It provides a very crucial method to
distinguish Split from TeV (normal) SUSY.
• All three modes (11), (12) and (22) should be
analyzed.
• Current and planning colliders can’t cover all
SS parameter space.
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Thanks for your attention!
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