3-sigma anomaly of W->tau nu decay

1
Part I 3-sigma anomaly of W-gttau nu decay in
new physics beyond SM ----first clean hint of
right-handed charge current? (hep-ph/0504123)
???(Shou-hua Zhu) Peking University July 2005 _at_
Tsinghua Univ.

• 3-sigma anomaly of W-gttau nu measurements
• Anomaly in 2HDM and MSSM
• Anomaly indicates right-handed charge current?

2
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

3

• ADL final
• O prel.

Anomaly mainly comes from L3
4
3-sigma anomaly of W-gttau measurements,
hep-ex/0412015
New physics?
5
3-sigma anomaly of W-gttau nu is especially
interesting and important

• In SM involved is only pure left-handed charge
  current
• Simpler kinematics and less hadronic
  uncertainties.

6
Possible explanations in new physics beyond the
SM

• Oblique-type corrections -gt NO!
• Flavor-dependent interaction!
• Satisfy neutral-current data (Z-decay) at O(0.1)
• Satisfy tau-gt nu_tau l nu_l data

• Tan(beta) enhancement flavor interactions
• Higgs-fermion Yukawa couplings in 2HDM
• Chargino(Neutrolino)-fermion couplings in MSSM

Positive!
7
2-Higgs doublet model (2HDM)
Negative except for near-degenerate Higgs mass
case
Lebedev etal.,
PRD62(2000)055014
8
MSSM

• Use FeynArts, FormCalc, LoopTools to scan
  parameter space
• In most cases, delta_new is negative
• In all cases

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
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.

13
Anomalous left- and right-handed couplings
From W-gttau nu_tau data
14
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-gtnu_tau l nu_l.
PDG(2004)
15
Allowed small regions at 95 CL
dR 0-gt 0.12 dL 1-gt 1.005
16
Anomalous left- and right-handed couplings for
3rd generation quark
From B-gtX_s gamma measurements
Re(dR)lt 4 ?10-3 for Wtb
F. Larios etal., PLB457
(1999)334 dR?
0.12 for W??

?
17
Summary for 1st part (questions)

• Is W-gttau 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)

18
Part IIDistinguishing Split from TeV (normal)
SUSY at ILChep-ph/0407072, PLB604,207(2004)

• ???
• Shou-hua Zhu
• Peking University
• July 2005_at_ Tsinghua Univ.

19
Outline

• Why Split SUSY (SS)?
• How to distinguish SS from TeV SUSY?
• Chargino pair production at Linear colliders
• Summary

20
Why Split SUSY? (I)

• Naturalness problem in the SM
• mHphy mH0 c ?2, ? ---new physics
  scale
• gt 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.

21

• TeV New Physics is an attracting thing (important
  basis of future colliders), but

22
Akani-Hamed, Pheno2005
23
S. Dawson, LP2005
24

• TeV SUSY is a beautiful thing (GUT, dark matter,
  aesthetic ), but

25
S. Dawson, LP2005
26

• Shortcomings of TeV SUSY
• not yet found Higgs ? small hierarchy problem
  (remind in MSSM at LO mHltMZ)
• excess flavor and CP violation gtCP problem
• fast dim-5 proton decay etc.

27

• Seems MNew Physics gtgtTeV, did we miss something
  important? Is that possible that naturalness ?

28
Why Split SUSY? (II)

• Failure of Naturalness of Cosmological Constant
  -gt

29
Akani-Hamed, Pheno2005
30

• Fine tuning gt
• God
• mechanisms

Assuming UNKNOWN mechanism for finely tuned CC is
also applied to Higgs sector
31

• 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 (120160 GeV)
• (d) cures to most of TeV SUSY diseases
  etc.

32
Akani-Hamed, Pheno2005
33
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

34
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

35
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.

36
SS Parameter Space Mixed Region

• Assuming gaugino mass unification and dark matter
  constraint
• 0.094 lt?DMh2lt0.129
• G. Giudice A. Romanino,
• hep-ph/0406088

37
Point Pa Differential ? and Forward-backward
Asymmetry
(11)
10 TeV
1 TeV
38
Point Pa total ?
(11), (12) and (22) are all sensitive to
sneutrino mass up to 10 TeV for lower M2 and ?.
39
Point Pb Total ?
(22) Mode is most promising for higher M2 and ? .
40
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 cant cover all
  SS parameter space.

41
Thanks for your attention!