Search for new physics
beyond the SM
Yasuhiro Okada (KEK/Sokendai)
June 12, 2009
KAON09, Tsukuba, Japan

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Content Introduction
 K->πνν Lepton universality
 T violation
 Light boson search Test of fundamental principles2

Early ’80 vs. Now
C.S. Lim’s opening talk reminded us of the situation in early
1980’s.
Top quark was anticipated, but the mass and the flavor mixing wasunknown.
 Inami and Lim showed that Flavor Changing Neutral Current
processes were sensitive to these unknown quantities.
Non-decoupling loop effects of the top quark.

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After a quarter of a century, we now know
•the top quark is heavy (mt~ 173 GeV) and•the Cabibbo-Kobayashi-Maskawa (CKM) matrix has a hierarchical structure.

Energy frontier and Flavor Physics

4Now, we are anticipating something new at the TeV
scale that is related to physics of the electroweak
symmetry breaking.
The first hint should appear at the LHC.
We do not know what are waiting for us (new particles,
new symmetry, new dimensions) except that we
probably find a “Higgs”-like particle.
New physics is likely to involve new sources of flavor
mixings, but the pattern of the new flavor mixing isunknown.

5Various possibilities on new physics effects(1) Minimal Flavor Violation

New physics contributions to flavor changing amplitudes are
essentially governed by the CKM matrix.
Characteristic relation between B and K observables.
(2) GenericNo particular relation between SM and new physics contributions.
New physics effects are more likely to appear in processes wherethe SM contributions have severe suppression.
a severe constraintA promising signal
a severe constraint/ a signal if theory is improved.
6+KL->πνν, K ->πνν
Theoretically clean processes. Ideal to search forsmall new physics effects.
 NNLO calculations (M.Gorbahn) Long distance effects (C. Smith)B(K0->π0νν)

(α)
(γ)

B(K+ -> π+νν)(β)

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M.Gorbahn

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M.Gorbahn
9Experimental prospects
CERN NA62 B(K+ ->πνν) 10% measurement G.Ruggiero
 J-PARC KOTO B(KL->πνν) ~SM
H.Nanjo

H.MoriiD.Bryman
10TeV new physics example: three cases(1) Little Higgs Model with T-parity•Little Higgs model : a model with a composite
Higgs boson.
N.Arkani-Hamed,A.G.Cohen, E.Katz,and A.E.Nelson,2002•New particles (heavy gauge bosons, a heavy
top partner) are introduced to cancel thequadratic divergence of the Higgs mass at
one loop level.
•The mass of these particles are around
1 TeV if the model is extended with “T parity”.
C.H.Cheng and I.Low,2003

At ~10 TeV, UV completion theory

At f ~ O(1) TeV
T-odd bosons: WH, ZH, φij,T-odd fermions: uH,dH,lHTop partners T+, T-Less than ~200 GeV
T-odd heavy photon AH
SM particles

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Flavor Physics in the Little Higgs model with T-parity
J.Hubisz,S.J.Lee,G.Paz, 2005

New flavor mixing from T-odd quark and lepton sectors.
qHu
VHd
VCKM
VHudduW

WH,ZH,AH

qH

WH,ZH,AH

Out of three mixing matrixes, two are independent.

Similarly, in the lepton sector,

These matrixes can induce a large contributions to FCNC and LFV processes.
(Non-MFV in general)12Effects of a new flavor mixing matrix: Non-MFV13

Large effects in KL->πνν, K+->πνν, or CP violation in Bs->ψφ14

(2)Rundall Sundram model with custodial protection
A model based on a warped extra
dimension. A large hierarchy between
the Planck scale and the weak scale isobtained by geometry,
An interesting frame work to explain
mass and flavor mixing of quarks andleptons.
FCNC processes are constraints
and signals of this model.

15A.Buras16

(3)
SUSYandK->πνν
There are a variety of possibilities in SUSY effects on flavor physics
from MFV to generic cases.
Generic MSSM

Minimal Flavor Violation (MFV)scenario
in minimal SUSY SM (MSSM)

Stop mass

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B(K0->π0νν)/B(K0->π0νν)SM1.5

10.5
Chargino mass

>15%

Stop mass>12.5%>10%
G.Isidori, et al. 2006

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Anomalous W couplings to charm quark

J.Tandean

Kaon processes put strong constraints especially for left-handed couplings.
For example,

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SUSY and lepton universality
P.Paradisi
One particularly interesting case is that the righthanded slepton flavor mixing induces the violation oflepton universality in K->lν decays.

19P.Paradisi

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Recent experimental results
NA62KLOE

E.Goudzovski

B.Sciascia

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Higgs effects at large tan β in MSSM
M.Palutan, E.Passemer, Flavianet
Coupling universality with Kl2, Kl3decay

Charged Higgs coupling test with B->τνB-Dτν and charged Higgs production at LHC
A. Cornell, A Deandrea,N.Gaur,
H.Itoh, M.Klassen, Y.O,

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+T-violation in K ->πνµ decay
J.Imazato
Current upper limit of the transverse muonpolarization of K+->πνµ decay is given by
KEK E246 exp.

J-PARC TREK experiment aim tosearch for δPT ~ 10-4.
Sensitive, for example, to CPV couplingsin multi-Higgs models.

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Effective four fermion interaction

The transverse polarization needs interference between the SM four fermion
term and new contributions and a relative phase between them.

24Light boson search
There are proposals postulating light bosons.
HyperCP, Dark Matter, Light U(1) gauge boson, etc.
 K decays put strong constraints.
KTeV Preliminary D.G.Phillips II

KEK E391a Y-C Tung X sgoldstino in GMSBHyperCP anomaly with pseudo
scalar is excluded.

Also

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Test on fundamental principles
A.Di Domenico

 K meson system is an ideal place to test CPT

invariance, Quantum Coherence, Lorentz
invariance. KLOE improved previous limits.
CPT

CPT violation in correlation
Quantum coherent

KLOE2 can improve further.
P.Branchini
etc.

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Summary Particle physics enters a new era from theLHC experiment.
 Energy frontier and flavor physics will becomplementary to each other.
 Kaon physics will provide several
opportunities which are unique in flavor
physics.

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