A window to the TeV scale and beyond from quark and lepton flavor physics Yasuhiro Okada (KEK/Sokendai) October 18, 2007 The 1st KPS-JPS joint session on particle physics, KPS meeting , Jeju, Korea

Role of flavor physics in the past Flavor physics has provided basic inputs to formulate the particle physics model. Absence of Lepton Flavor Violation in charged lepton decays => Two neutrino theory (Generation structure) Suppression of Flavor Changing Neutral Current Processes => GIM mechanism (Charm quark) CP violation in K decays => Kobayashi-Maskawa theory (Three generation structure) “Basis of the Standard Model”

Critical time for particle physics LHC experiment will start next year to explore the TeV physics. TeV is the scale of the electroweak symmetry breaking, but most probably related to the “New Physics” scale. New flavor experiments are under construction, (LHCb, BESSIII, MEG). Future upgrade of the B factory is planned to improve capability of B, tau and charm physics.

Precision measurements Precision measurements can provide indirect evidence of new physics or hints of physics at very high energy scales. Impacts of LEP precision electroweak measurements SUSY GUT? A light Higgs boson?

The Unitarity triangle today Although the CKM fit looks perfect, new physics contributions of several 10 % are still allowed. Need more precision to be useful to explore the TeV physics.

Lepton Flavor Violation No lepton flavor violation (LFV) in the Standard Model. LFV in charged lepton processes is negligibly small for a simple seesaw　neutrino model. The MEG experiment will search for m ->e g up to 10-13 level. Y.Kuno and Y.O. 2001

Tau LFV Current bounds of tau LFV decays are 0(10-7) . Relation between mu LFV and tau LFV depends on new physics models. t ->eg upper bound t ->mg upper bound S.Banerjee, TAU 06

New physics examples SUSY GUT and quark and lepton flavor signals (New physics in loops) Charged Higgs interaction in B to tau decays (New tree-level interaction) Neutrino mass generation and LFV

SUSY and Flavor Physics SUSY modes introduce SUSY partners. Squark/sleption mass matrixes are new sources of flavor mixing and CP violation. Super partners SM particles neutralino, chargino gluino slepton squark W,Z,g, H gluon lepton quark Spin 1/2 Spin 0 Spin 1 Spin 1/2 Spin 1 Spin 1/2 Spin 0 Quark mass Squark mass SUSY breaking

SUSY breaking terms Quark flavor changing processes LHC/ILC SUSY mass spectrum Diagonal Off-diagonal Lepton flavor violation

SU(5) SUSY GUT with right-handed neutrinos In the SUSY GUT case, the quark (neutrino) Yukawa coupling becomes a source of LFV (quark FCNC). Quark Yukawa coupling Neutrino Yukawa coupling GUT interactions Quark flavor signals Time-dep CP asymmetries in B->fKs B -> K*g Bs->J/yf Lepton flavor violation in m->eg t->mg t->eg

Examples of flavor signals Mixing-induced CP asymmetry: S(B->K*g) DS(fKs)=S(B->fKs)-S(B->J/yKs) SuperB SuperB T.Goto, Y.O., T.Shindou and M.Tanaka, 2007

S(Bs->J/yf) LFV ( t ->mg, m->eg) t->mg LHCb m->eg t->eg T.Goto, Y.O., T.Shindou and M.Tanaka, 2007 Tau LFV and CPV in Bs mixing are correlated with Bd CPV signals.

Pattern of new physics signals in various SUSY models. T.Goto, Y.O., T.Shindou and M.Tanaka, 2007 Promising signals Possible deviations for some points Pattern of deviations from the SM can provide a clue on physics determining the structure of the SUSY breaking sector.

B to tau decays (B->tn, B->Dtn, B->D*tn) New data from Belle and BABAR. (Belle+BABAR) (Belle) (BABAR) Sensitive to charged Higgs boson exchange diagrams.

Tauonic B decay The charged Higgs boson exchange diagram exists in Two Higgs doublet model as well as SUSY models. New contributions are important for the large tanb case b u t n W B(B->tn) Belle+BABAR H- b u t n Charged Higgs exchange contribution depends on

Correlation between B->tn and B->Dtn MSSM with minimal flavor violation (MFV) B(B->tn) Belle+BABAR B(B->Dtn)/B(B->Dmn) Interesting to measure B->Dtn mode to resolve the twofold ambiguity. H.Itoh, S.Komine, Y.O. 2005

Comparison with charged Higgs boson production at LHC K.A.Assamagan, Y.Coadou, A.Deandrea　2002 B->Dtn 50ab-1 Sensitive to the same parameter space. Test of “universality” of the charged Higgs couplings. B->tn: H-b-u coupling B->Dtn : H-b-c coupling gb->tH: H-b-t coupling

Neutrino and LFV LFV is negligible for the simple seesaw model. If some new ingredient is combined with the idea of the seesaw neutrino, LFV can be observable. Tau processes have many modes whereas mu processes are more stringent in general. and their CP conjugates Present bounds 0(10-7) Present bound 10-11-10-12

Left-right symmetric model The LR symmetric model realizes a TeV scale seesaw mechanism. LFV is induced by doubly charged Higgs bosons. A example of tau and mu LFV processes A.Akeroyd, M.Aoki, Y.O,2006

This is compared with the SUSY GUT with seesaw This is compared with the SUSY seesaw model where SUSY loop diagrams gives dominant contributions. t->mg t->eg Signals in different modes. B(m->eg) T.Goto, Y.O., T.Shindou and M.Tanaka, 2007

Summary Quark flavor changing neutral current processes, rare decays and lepton flavor violation offer opportunities to search for new physics at the TeV scale in a different way from LHC. If some new physics signals are observed, combinations of various signals can provide a hint for physics at higher scales. In order for the flavor physics to be useful in the coming LHC era, the precision of various flavor measurements must be significantly improved, both in terms of experimental reach and understanding of theoretical uncertainty.