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Outlook: Higgs, SUSY, flavor
Ken-ichi Hikasa (Tohoku U.)
Fourth Workshop, Origin of Mass and SUSYMarch 8, 2006, Epochal Tsukuba
Apology
This is not designed to be a summary talk…, so no reference to most of the talks
Standard Model
SM = GHY
Three elements G: gauge H: Higgs Y: Yukawa
SM = GHY
Three elements G: gauge D
H: Higgs Y: Yukawa
All gauge interactions from D = + ig A
Universality: unique coupling, blindness to generations
SM = GHY Three elements
G: gauge H: Higgs 4
Y: Yukawa
Symmetry breaking, W,Z masses Higgs mass term 2: only dimensional
parameter in SM (classically) sets the weak scale
SM = GHY
Three elements G: gauge H: Higgs Y: Yukawa y f f
Fermion couplings to Higgs field give masses to quarks/leptons
SM = GHY
Three elements G: gauge D
H: Higgs Y: Yukawa
Only interaction experimentally confirmed: 2/3 of SM still to be tested
SM = GHY
Three elements G: gauge H: Higgs Y: Yukawa yij fi fj
No ‘universality’: origin of flavor difference and mixing
Most # of parameters in SM
Generation mixing
u1
u2
d1
d2
If no Yukawa coupling, generation labels has no meaning
Generation mixing
u1
u2
d1
d2
Charged current interactions connects ups and downs
W±
Generation mixing
Yukawa couplings breaks the generation symmetry
u1
u2
d1
d2
u
c
d
s
Generation mixing
Mismatch of ups and downs gives the Cabibbo mixing
u1
u2
d1
d2
u
c
d
s
C
W
Leptons
If the neutrinos were massless…
1
2
1
2
e
Leptons
Neutrino eigenstates can be defined only by charged currentand the lepton flavors are conserved
1
2
1
2
e
e
Neutrino mass (side remark)
In SM, is made to be massless Quark-lepton correspondence
Naturally expect R & Yukawa R : gauge blind particle (hard to see)
Ultratiny mass suggests different origin Important question: Dirac or Majorana?
Higgs sector
Iweak = ½ Rule
Quark/lepton masses have to be Iweak = ½ W, Z masses can have any Iweak
Precision measurements: experimental evidence for Iweak = ½ dominance
Iweak = ½ Rule
=1 to high precision doublet vev dominance
Indirect Higgs limit
Mtop (GeV)
MW
(GeV
)
150 175 200
80.5
80.4
80.3
Direct Higgs searches Still a long way to go, but worth pursueing
MSSM implies light Higgs
MSSM/two doublet Large tan region started to be excluded at Tevatron
A0 +-
Beyond SM
Standard Model is not the final story
(Observational) reasons we need BSM
Gravity Dark Matter Dark Energy Baryon asymmetry CMB Neutrino mass
(Theoretical) reasons we need BSM
No strong CP violation Hierarchy problem? Too many parameters? Unification of gravity
Where to seek for BSM New particles
Energy frontier Faint interactions (can be light)
Forbidden processes baryon # violation lepton # violation lepton flavor violation (seen in oscillations, but very small)
Suppressed processes
Weak interaction processes
Superallowedt b, c s
CKM suppressed (tree-allowed but small) b c, u; s u
GIM suppressed (tree-forbidden) FCNC b s, d; s dGood place to look for new physics
BSM Scenarios
SupersymmetryRaison d’être aka excuse:
Unique nontrivial extension of the Poincaré group (= Einstein’s relativity)
Motivation @ weak scale:
Stabilize Fermi-Planck hierarchy by cancelling loop corrections
Extra DimensionsRaison d’être aka excuse:
Superstrings require 10 spacetime dimensions for consistency
Motivation @ weak scale:
(Originally) trading the Fermi-Planck hierarchy for large extra-dim size
More recently, branes, Randall-Sundrum hierarchy, …
Extra Dimensions
All SM interactions are nonrenormalizable for D>5 Couplings tend to blow up above weak scale: Strong-coupling phenomena at TeV (Technicolor-type physics)
Higgsless models: Heavy W,Z recurrences should appear
And many others
Minimal Supersymmetric Standard Model
MSSM
Many parameters (>100) New sources of flavor structure
Sfermion masses (left and right) LR mixing (A term)
New sources of CP violation LSP neutralino: good DM candidate
D-squark mass matrix
2 2 2
2 2 2
2 2 2
dd ds db
sd ss sb
bd bs bb
m m m
m m m
m m m
One new source of flavor mixing
D-squark mass matrix
2 2 2
2 2 2
2 2 2
dd ds db
sd ss sb
bd bs bb
m m m
m m m
m m m
Chiral substructure of sfermion mass
2 2
2 2bLsL bLsR
bRsL bRsR
m m
m m
Vast parameter space
Most regions contradict with neutral Kaon mixing
mSUGRA, CMSSM: tiny regions in the parameter space Useful as a guideline Should not trust too much
Varied phenomenology
Different mass patterns Generally: colored > noncolored Split SUSY: scalars > gauginos Focus point: light higgsinos
Interesting alternatives Gauge mediation: stau LSP Anomaly mediation: light wino R parity violation: exotic resonances
Dark Matter
Rare b decays In SM, b s is much more suppressed than b
c good place for new physics b-s sfermion mixing can contribute to CP asym
metry
New physics effects on b s
Sign of SUSY contributions
Extra contribution to sL
Same sign deviation for B K and ’K New mixing of sR
Opposite sign deviation for B K and ’K
Consequence of possible deviation
If both K and ’K deviates in the same direction, new physics are in the left-handed sector
(the data are old)
Endo, Mishima, Yamaguchi
Lepton-flavor violation
Neutrino mass mixing: way too small effect on charged lepton FV
Supersymmetry: slepton mass matrix gives new LFV source GUT: quark mixing lepton mixing Right-handed new mixing source Observable effect expected in , e etc.
Conclusions
Conclusions
Tevatron has plunged into new luminosity frontier SM Higgs: important target to pursue MSSM/Two doublet: already started to constrai
n parameter space Supersymmetry, XD, etc: Don’t wait for LHC
Conclusions (cont’d)
B factories Very rich physics output Good measurements of all 3 angles Hint of new physics?? LFV: unique place to seek for BSM
Kaon physics should not be discontinued
Future
2 2 2
2 2 2
2 2 2
dd ds db
sd ss sb
bd bs bb
m m m
m m m
m m m
LHC, ILC
B physics
K physics
One final remark
‘Mass-origin’ priority-area grant ends in one month,
but
We are still on the way!