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The impact of rare K decays in The impact of rare K decays in New Physics searches New Physics searches Federico Mescia INFN-Frascati Golden Modes Standard Model Experiment + + + + 11 E787 1.1 13.0 11

slide-1
SLIDE 1

The impact of rare K decays in New Physics searches The impact of rare K decays in New Physics searches

Federico Mescia

INFN-Frascati

Experiment Standard Model Golden Modes

10

2.8 10− < ×

10

3.8 10− < ×

KTeV

1.1 11 0.9

3.7 10

+ − −

×

0.3 11 0.3

1.5 10

+ − −

×

0.4 0.4

11

2.9 10

+ −

−

×

1.1 1.1

11

8.0 10

+ −

−

×

+ +

→ π νν K

13.0 11 8.9

14.7 10

+ − −

×

E787 E949

L

K → π νν

L

K

+ −

→ π µ µ

L

K e e

+ −

→ π

7

2.9 10− < ×

E391a KTeV

1

CKM 2006 - December 12-16, 2006 - Nagoya

slide-2
SLIDE 2

2

13.0 11 8.9

[E787-E949] ( ) 14.7 10

+ + + − −

→π νν = × B K

2 6 2 6 2 6

( ) 4.4 ( ) [Grosm ann - Nir Bound]

+ +

→ π νν ≤ → π νν

L

B K B K

KL→πνν÷K+→πνν: uncertainties at 15% due to present CKM accuracy

slide-3
SLIDE 3

3

KL→π0νν − K+→π+νν: high-precision discovery lens!

at 5% uncertainties with CKM updates from Babar/Belle/LHCb

2 1 2 1 2 1

large room for New Physics

essential exp. info

slide-4
SLIDE 4

4

large unexplored room in principle, but

  • is it still possible to expect deviations, despite constraints from the large

amount of processes compatible with the Standard Model?

reminder

  • tree-level processes → disfavoured for NP searches, normally (MW/Λ)2≤1%

(Mind at special cases Mind at special cases, , Paride’s Paride’s talk talk)

  • FCNC loop processes → suitable for NP, only measured ∆B= 2, ∆S= 2 and ∆B= 1

transitions

  • K rare decays → s→d coupling and highest CKM suppression→ like ε’/ε

very clean→ like sin2β

1 in any case, LHC will saturate the room left, won’t it?

  • ATLAS-CMS → new particles at the TeV scale by flavour conserving channels

complementarity information @TeV

  • LHCb at work → Bs→µµ and Bd→µµ, information on b→s/b→d couplings

2 K→πνν & K→π can give some surprise, with small effects in B and EWPT Moreover, clean probe to higher scale Λflav~100 TeV

Let’s not forget “The definitive answer is from experiments”

  • G. Galileo
  • G. Galileo
slide-5
SLIDE 5

5

Two classes of “Beyond SM” scenarios:

  • 1. Minimal Flavour Violation:

flavour breaking induced only by SM Yukawa couplings, YU & YD. (Y: Wilson coefficient at Λflav»1 TeV )

  • 2. New sources of Flavour Symmetry

breaking arising at the TeV scale

→ Cecilia & Buras

  • s→d new couplings no longer O(λ5) suppressed

(s→d)BMFV = O(λ5)×SM + O(1)×(new d.o.f)

  • Many proposed models already killed from

present data (B, K, EWPT & DM)

  • One order of magnitude enhancement still

possible in MSSM and LHT B(KL→π0νν) ≤ 510−10 in reach of E391a upgrade

  • SM hierarchy of FV couplings:

(s→d)MFV = O(λ5)×[ SM + new d.o.f ]

  • Specific realisations in SUSY, UED, LH,

EFT

  • Small deviations in specific models:

B(KL→π0νν) ≤ O(20%-30%)

  • In specific models, stringent correlations

can rise with either B physics (B→, B→X, B→Xνν) or EWPT (∆ρ)

Pattern: effects on B(KL→π0νν) > B(K+→π+νν) > B(KL→π0) Peculiarity: Peculiarity: K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

slide-6
SLIDE 6

6

Two classes of “Beyond SM” scenarios:

  • 1. Minimal Flavour Violation:

flavour breaking induced only by SM Yukawa couplings, YU & YD. (Y: Wilson coefficient at Λflav»1 TeV )

  • 2. New sources of Flavour Symmetry

breaking arising at the TeV scale

→ Cecilia & Buras

  • s→d new couplings no longer O(λ5) suppressed

(s→d)BMFV = O(λ5)×SM + O(1)×(new d.o.f)

  • Many proposed models already killed from

present data (B, K, EWPT & DM)

  • One order of magnitude enhancement still

possible in MSSM and LHT B(KL→π0νν) ≤ 510−10 in reach of E391a upgrade

  • SM hierarchy of FV couplings:

(s→d)MFV = O(λ5)×[ SM + new d.o.f ]

  • Specific realisations in SUSY, UED, LH,

EFT

  • Small deviations in specific models:

B(KL→π0νν) ≤ O(20%-30%)

  • In specific models, stringent correlations

can rise with either B physics (B→, B→X, B→Xνν) or EWPT (∆ρ)

Pattern: effects on B(KL→π0νν) > B(K+→π+νν) > B(K+→π+) Peculiarity: Peculiarity: K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

slide-7
SLIDE 7

7

Two classes of “Beyond SM” scenarios:

  • 1. Minimal Flavour Violation:

flavour breaking induced only by SM Yukawa couplings, YU & YD. (Y: Wilson coefficient at Λflav»1 TeV )

  • 2. New sources of Flavour Symmetry

breaking arising at the TeV scale

→ Cecilia & Buras

  • s→d new couplings no longer O(λ5) suppressed

(s→d)BMFV = O(λ5)×SM + O(1)×(new d.o.f)

  • Many proposed models already killed from

present data (B, K, EWPT & DM)

  • One order of magnitude enhancement still

possible in MSSM and LHT B(KL→π0νν) ≤ 510−10 in reach of E391a upgrade

  • SM hierarchy of FV couplings:

(s→d)MFV = O(λ5)×[ SM + new d.o.f ]

  • Specific realisations in SUSY, UED, LH,

EFT

  • Small deviations in specific models:

B(KL→π0νν) ≤ O(20%-30%)

  • In specific models, stringent correlations

can rise with either B physics (B→, B→X, B→Xνν) or EWPT (∆ρ)

Pattern: effects on B(KL→π0νν) > B(K+→π+νν) > B(K+→π+) Peculiarity: Peculiarity: K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

slide-8
SLIDE 8

8

D’Ambrosio,Giudice,Isidori,Strumia (02)

L L eff gauge i i R R c D 6 6 i i 2 i fla U v

(A ,Q ,H) + Q D H Q U H + Y Y c O ⋅ + + Λ

∑

…

  • L

= L

SM

L

YD & YU regulate flavour violation: U(3)5 U(3)5 flavour group

new new d.o.f d.o.f @ @ TeV TeV O6 → functions of SM fields and YD-YU spurions, made invariant

  • f U(3)5≡SU(3)5⊗B⊗L⊗CP.
  • c6 → universal and real coef.

Minim al Flavour Violation→ U(3)5EFT at TeV

see Grinstein’s talk

slide-9
SLIDE 9

9

D’Ambrosio,Giudice,Isidori,Strumia (02)

Minim al Flavour Violation→ U(3)5EFT at TeV

1. CKM suppression (O(λ5)) still on; 2. the X coefficient unbounded from B processes or εK

[ ] [ ]

2 * 2 * 2

( sin ) ( ) 1 sign ( ) ( ) 1 sign

+ + + +

→ π νν → π νν × + ε → π νν → π νν + ε ∝ β

  • L

L c ts td ts M t S d c

SM

X X X V V V V B K B K X B K B K

L L eff gauge i i R R c D 6 6 i i 2 i fla U v

(A ,Q ,H) + Q D H Q U H + Y Y c O ⋅ + + Λ

∑

…

  • L

= L ( )(

)

( )( ) ( )( ) ( )( ) ( ) ( )( ) ( )( ) ( )( )

6 6 1 2 6 6 3 4 6 6 5 6 / / * * * / µ µ µ µ µ µ µ µ µ µ µν µ µ µ µ µ

γ γ τγ τ γ γ τγ γ τ γ σ γ γ νγ ν γ

+ + + + + + + + +

⎫ + + ⎪ ⎪ + → ⎬ ⎪ ⎪ + ⎭

  • L

L L

V A L L L L L V A L L L L L L V A L L R v L L L L L ts td ts U U U U U U U U tb ts U U U U U L d U D L t

s d K s d ll Q Q H D H Q Q H D H Q Q L L Q Q L L K b s D Q Y Y Y Y Y Y Y Y V V Y Y Y Y Y Y F Q Q Q Q X V V V c c V Y c c c c

( )( ) ( )( ) ( ) ( )( )

* * * / / / 7

...

µ µν µ µ µ

γ σ γ γ + +

L L L

b L V A L V A V A R v tb td tb ts L L L ts td

ll K b d ll C b V s F B s d s d m V V V V V

13 operators 13 operators

K K-

  • rare

rare decays decays

/ /

, , , →πνν →π ε → → γ

  • K

s d s d

K K B X B X K K-

  • rare decays

rare decays

D’Ambrosio,Giudice,Isidori,Strumia (02)

( )

* 2 2

/

+

∝

t W U U ij

t

ti j

Y m V m V Y

slide-10
SLIDE 10

MFV

model independent ap.

[ ]

( ) ( ) 1 sign ( ) ( )

+ + + +

→ π νν → π νν = × + ε → π νν → π νν

L L c

MFV SM

B K B K B K B K X

10

MFV enhancement: B(KL→π0νν) ≤ 4.6 BSM

B(K+→π+νν)/ B(KL→π0νν) ∼SM

slide-11
SLIDE 11

11

MFV- Specific Scenarios

In a given model implementation, X bounded trough EWPT & B data. Deviations from SM can get smaller

1 . MFV- Phenom enological Model (CMFV)

Buras,Gambino,Gorbahn,Jäger,Silvestrni (00)

  • nly Standard Model operators

Bobeth,Bona,Buras,Ewerth,Pierini,Silvetrini,Weiler (05)

2 7 7

( ) ( ) ( ) , , ( ) , , ,

Model d. Model d.

⎫ →πνν → → γ ≅ ⎧ ⎪ ⎪ ⎯⎯⎯⎯⎯ → ⎯⎯⎯ ⎛ ⎞ ⎜ ⎟ ⎝ ⎠ ⎯⎯ → ⎬ ⎨ →π → ⎪ ⎩ ⎪ → → ⎭

≅ =

  • e

ef s f f s f

B C C K B B X B K B B Y Z Y Z Y E X E X Z

X Y E

  • box and g-peng. d.o.f frozen

to their SM value

X -> constrained by B processes X -> constrained by B processes

( )

  • 1
  • 4

4

νν νν γ

= + = +

ll

B B X D Z B Y X

s.d. couplings gauge invariant

slide-12
SLIDE 12

Analysis on MFV-Phenom enological Model

Bobeth,Bona,Buras,Ewerth,Pierini,Silvetrini,Weiler (05)

X≅Y and E≅0

SM

  • Excl. at 68% CL

E787-E949 lower bound

12

at 9 5 % CL

O(20-50%) enhancement

B(KL→π0νν) ≤ 1.6 BSM B(K+→π+νν)/ B(KL→π0νν) ~SM

MFV-EFT: X free Outcome:

D’Ambrosio,Giudice,Isidori,Strumia (02)

[ ]

( ) ( ) 1 sign ( ) ( )

+ + + +

→π νν →π νν = × +ε →π νν →π νν

L L c

MFV SM

B K B K B K B K X

MFV + Exp. Evidence of K+ excludes small vanishing KL BR

slide-13
SLIDE 13

13

MFV- Specific Scenarios

In a given model implementation, X bounded trough EWPT, B & K data. Deviations from SM can get smaller

1 . MFV-Phenom enological Model (CMFV)

Buras,Gambino,Gorbahn,Jäger,Silvestrni (00)

  • nly Standard Model operators

Bobeth,Bona,Buras,Ewerth,Pierini,Silvetrini,Weiler (05)

2 7 7

( ) ( ) ( ) , , ( ) , , ,

M odel d. M odel d.

⎫ → πν ν → → γ ≅ ⎧ ⎪ ⎪ ⎯ ⎯ ⎯ ⎯ ⎯ → ⎯ ⎯ ⎯ ⎛ ⎞ ⎜ ⎟ ⎝ ⎠ ⎯ ⎯ → ⎬ ⎨ → π → ⎪ ⎩ ⎪ → → ⎭

≅ =

  • e

ef s f f s f

B C C K B B X B K B B Y Z Y Z Y E X E X Z

X Y E

  • box and g-peng. d.o.f frozen

to their SM value

2 . MFV+ SUSY- Msugra-like

D’Ambrosio,Giudice,Isidori,Strumia (02)

  • (

) ( ) ( ) ( )

2 2 2 2 † 2

6 6

⎛ ⎞ ⎜ ⎟ =⎜ ⎟ ⎝ ⎠

  • u

U R U RL L R L U U R L

x

m m M m m

a) SUSY→

( ) ( )

2 2 2 2 2 1 1...

1... ∝ ∝

U LL U RR

m a m a

( ) ( )

* 4 2

cot = −µ β

U RL u

m a M

  • spectrum:SM+4Higgs+SUSY partners

H & H &χ χ interactions interactions ruled ruled by CKM by CKM (super CKM basis) (super CKM basis)

  • dark matter candidate
  • stabilization of Higgs sector

b) MFV→

  • scalar soft breaking terms

proportional to SM Yukawa couplings

slide-14
SLIDE 14

Largest effects by and , since enhanced by the large top mass down top H+ down stopR χ+

mt mt

Nir,Worah(98)/Buras,Romanino,Silvestrini(98)/Colangelo,Isidori(98)

Analysis on MFV-MSSM (R-parity)

Isidori,F.M,Paradisi,Trine,Smith (06)

14

+perm.+boxes no FV via gluino/neutralino

2 2 * + ∝

×

ts td t W

W m V M V

* 2 2 2 2 2 cot + ∝

× β

ts t t H W d t

m M m H M V V

2 2 2 * 2 4 * 2

cot

+

χ +

χ − ∝ µ β

  • ts

t t d W t W

M a m M M M V V

  • common CKM factor
  • enhancements due to flavour

conserving parameters:

  • 1. small tanβ→ 2
  • 2. light spectrum;

stop→ 150 GeV chargino→ 150 GeV charged Higgs→ 300 GeV

  • 3. large a4 ;maximal effects

for sign(µ)=−sign(a4)

  • Upper limits

B(KL→π0νν) ≤ 1.25 BSM

Isidori,F.M,Paradisi,Trine,Smith (06)

⇔ LHC

  • the largest correlation from ∆ρ

Buras,Gambino,Gorbahn,Jager,Silvestrini (00)

slide-15
SLIDE 15

15

Two classes of “Beyond SM” scenarios:

  • 2. New sources of Flavour Symmetry

breaking arising at the TeV scale

MSSM: generic insertions

120 parameters free! MAMMA MIA!

and … 27 new Flavour Changing couplings along the squark lines. W hat can w e ever learn from K W hat can w e ever learn from K-

  • rare?

rare?

  • (

)

2 q

j i

M

x

i

q

j

q

slide-16
SLIDE 16

W hat can w e ever learn from K W hat can w e ever learn from K-

  • rare?

rare?

gluino, neutralino and chargino New FCNC transitions by

  • (

)

2

∝ αs

d ij

M

  • (

)

2

∝αw

d ij

M

  • (

)

2

∝αw

u ij

M

16

Nir,Worah(98)/Buras,Romanino,Silvestrini(98)/Colangelo,Isidori(98)

The interplay between SU(2)L⊗U(1) and Flavour symmetry prevents strong headaches:

⇒ appreciable sensitivity only to χ-up-squark

diagrams by 1 effective coupling

( ) ( )

32* 31 2 2

→ i

U U RL RL

m m

( ) ( )

3 3 2

cot = −µ β

t j j U U RL

m A m ⇒ gluino diagrams negligible;

2. LR mass insertions → propto to quark masses → 1. SU(2)L-conserving insertions, MLL/ RR → q2/m2

Z suppressed

slide-17
SLIDE 17

W hat can w e ever learn from K W hat can w e ever learn from K-

  • rare?

rare? a lot a lot

( ) ( )

2

cot = − µ β

u ij U ij U RL

m A M

K K→ →πνν πνν are the are the best probe best probe of the flavour

  • f the flavour

structure of the structure of the AU terms (∝Mt)

17

Isidori,F.M,Paradisi,Trine,Smith (06)

A-terms still unconstrained from B physics. small effects on LHcb/SuperB searches!

“Houston, we have a problem”

LHC - spectrum

slide-18
SLIDE 18

18

CPV observables at comparison: CPV observables at comparison: large room left due to large room left due to the the AU terms small impact on εK & sinβ, complementarity to LHCb/SuperB

Isidori,F.M,Paradisi,Trine,Smith (06)

slide-19
SLIDE 19

How sizable are these effects? big

19

  • appreciable sensitivity only to one effective

coupling

Buras,Ewerth,Jäger,Rosiek (04)

Grossman-Nir bound is saturated B(KL→π0νν) ∼30 BSM

  • Excl. at 68% CL

E787-E949

slide-20
SLIDE 20

K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

special opportunity to special opportunity to New Physics New Physics Searches Searches

20

slide-21
SLIDE 21

KL→π0µµ − KL→π0ee correlation K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

  • 1. alike to K→πνν →

→ χs by γ & Ζ peng.; ; visible visible effects on current-current

  • perators

Smith@BEACH06/F.M, Trine, Smith (06);

( )

5 7 7

( ) ( ) ( ) ( ) ) ( )(

µ µ µ µ µ µ

→ = νγ ν + γ + γ γ γ γ γ

  • BSM

eff A L L V

s d s H s y d d X y s d

21

F.M,Trine,Smith (06);

slide-22
SLIDE 22

KL→π0µµ − KL→π0ee correlation K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

22

  • 1. alike to K→πνν →

→ χs by γ & Ζ peng.; ; visible visible effects on current-current

  • perators
  • 2. contrary to K→πνν →

→ sensitive to

helicity-suppressed operators

5

( )( ) ) ( ( ) + + γ

  • S

P

y y sd sd

F.M, Trine, Smith (06)

( )

5 7 7

( ) ( ) ( ) ( ) ) ( )(

µ µ µ µ µ µ

→ = νγ ν + γ + γ γ γ γ γ

  • BSM

eff A L L V

s d s H s y d d X y s d

Retico, Isidori (02)/Buras,Chankowaki,Rosiek,Slawianowska(02)/

Foster ,Okumura,Roszkowski (05)

→ H0 penguins at large tanβ (as B→ →µµ, µµ, but different mass insertions) but different mass insertions) copiare copiare papers papers

slide-23
SLIDE 23

Conclusions Conclusions

Combining all present th. and exp. information , large deviations on K→πνν & K→π are still possible Combining all present th. and exp. information , large deviations on K→πνν & K→π are still possible

MFV:

  • D’Ambrosio et
  • al. ph-0207036

MSSM:

  • Buras et al.

ph-0408142.

  • Isidori et al.

ph-0604074.

  • Mescia et al.

ph-0606081

LHT:

  • Blanke et al.

ph-0604074

E787-E949

ex-0403034 ex-0403036

E787-E949

ex-0403034 ex-0403036

GN Bound ph-9701313 GN Bound ph-9701313

  • Buras et al.

ph-0505110 23

K-rare decays ⇒ large not covered parameter space!

  • complementarity to Atlas/CMS searches ⇒ new particles
  • supplementarity to LHcb/SuperB activities ⇒ gluinos
slide-24
SLIDE 24

BACKUP

24

slide-25
SLIDE 25

25

MSSM: SUSY model at low-energy

27 FC mass insertions free.

MSSM: SUSY model at low-energy

  • particle content: SM+4Higgs+SUSY partners
  • SUSY softly broken→ trilinear scalar couplings, squark/slepton and

chargino, masses

  • R-parity conservation→ dark matter candidate

2 2 2 χ

= φ φ φ + φ φ + χ χ L soft

ijk i j k x s

M M A

new source of flavour violation

  • (

) ( ) ( ) ( )

2 2 / 2 † 2 2 / /

6 6

⎛ ⎞ ⎜ ⎟ = ⎜ ⎟ ⎝ ⎠

  • Q

U D LL RL U D U D RL RR q

x

m m M m m

  • (

)

2 q

j i

M

x

i

q

j

q

⇔ LHC task

slide-26
SLIDE 26

26

MFV-Phenomenological Model

Buras,Gambino,Gorbahn,Jäger,Silvestrni (00)

  • “stronger’’ correlations between K & B decays, module to neglect box contr.

& poorly constrained γ couplings → X≅Y and E=0

Bobeth,Bona,Buras,Ewerth,Pierini,Silvetrini,Weiler (05)

measured fixed free parameters frozen to SM weakly constrained within present

  • exp. accuracy

X≅Y and E=0

slide-27
SLIDE 27

KL→π0µµ − KL→π0ee correlation K KL

L→

→π π0

0µµ

µµ − − K KL

L→

→π π0

0ee

ee correlation correlation

  • 1. like K→πνν →

→ χs by γ & Ζ peng.; ; visible visible effects on current-current operators

  • 2. contrary to K→πνν →

→ sensitive to

helicity-suppressed operators

5

( )( ) ) ( ( ) + + γ

  • S

P

y y sd sd

F.M, Trine, Smith (06)

( )

5 7 7

( ) ( ) ( ) ( ) ) ( )(

µ µ µ µ µ µ

→ = νγ ν + γ + γ γ γ γ γ

  • BSM

eff A L L V

s d s H s y d d X y s d

→ H0 penguins at large tanβ (as B→ →µµ, µµ, but different mass insertions) but different mass insertions)

Retico, Isidori (02)/Buras,Chankowaki,Rosiek,Slawianowska(02)/

Foster ,Okumura,Roszkowski (05)

27

slide-28
SLIDE 28

FCNC FCNC asymmetries and branching ratios within a asymmetries and branching ratios within a th

  • th. err

. err ≤ ≤ 15% 15% K→πνν peculiarities: highest CKM suppression and ∆S=1 coupling→ like ε’/ε very clean→ like sin2β

28

QCD M. E. QCD M. E. ∆ ∆F=2 b. F=2 b. ∆ ∆F=1 b. F=1 b. g g-

  • pen.

pen. γ γ− −pen. pen. Z Z-

  • pen

pen H H-

  • pen.

pen. ∆Ms 1 + 4 Bi OPE OPE fB

  • 1 + 4 Bi

OPE fB

  • 1 + 4 BK

known Known + BT Bd→ Xs γ Bd→ Xs Bs→ ACP(Bs→ψφ) εΚ KL→π0νν K+→π+νν KL→π0 ACP(Bd→φΚ) ∆Md Bd→ Xd γ Bd→ ACP(Bd→ψΚs) s→d Ο(λ5) tiny b→s Ο(λ2) small b→d Ο(λ3) b G s

µν µν

σ b F s

µν µν

σ b s Γ Γ

  • b

s Γ Γ

  • b

s b s Γ Γ

⊗ ⊗ ⊗ ⊗ ⊗

b d b d Γ Γ

b G d

µν µν

σ

b F d

µν µν

σ b d Γ Γ b d Γ Γ

⊗ ⊗ ⊗

s d s d Γ Γ s dν ν Γ Γ s d Γ Γ

  • s

dν ν Γ Γ s d Γ Γ

  • s

F d

µν µν

σ

measured ≤ ≤ 5% Th err.

slide-29
SLIDE 29

29

W hat can w e ever learn from K W hat can w e ever learn from K-

  • rare?

rare?

Nir,Worah(98)/Buras,Romanino,Silvestrini(98)/Colangelo,Isidori(98)

1. gluino diagrams negligible→ reduced sensitivity to LL/RR SU(2)L-conserving insertion and LR suppressed by down quark masses

gluino, neutralino and chargino New FCNC transitions by

  • (

)

2

∝αs

d ij

M

  • (

)

2

∝αw

d ij

M

  • (

)

2

∝α

w u ij

M The interplay between SU(2)L⊗U(1) and Flavour symmetry prevents strong headaches.

  • 2. appreciable sensitivity only, to χ-up-squark

diagrams by 1 effective coupling

( ) ( )

32* 31 2 2

→ i

U U RL RL

m m

  • (

) ( )

2

cot = − µ β

ij ij D D d RL

m A M

slide-30
SLIDE 30

30

slide-31
SLIDE 31

31

slide-32
SLIDE 32

W hat can w e ever learn from K W hat can w e ever learn from K-

  • rare?

rare?

gluino, neutralino and chargino New FCNC transitions by

  • (

)

2

∝αs

d ij

M

  • (

)

2

∝αw

d ij

M

  • (

)

2

∝αw

u ij

M

32

Nir,Worah(98)/Buras,Romanino,Silvestrini(98)/Colangelo,Isidori(98)

1. gluino diagrams negligible→ reduced sensitivity to LL/RR SU(2)L-conserving insertion and LR suppressed by down quark masses

The interplay between SU(2)L⊗U(1) and Flavour symmetry prevents strong headaches.

  • 2. appreciable sensitivity only, to χ-up-squark

diagrams by 1 effective coupling

( ) ( )

32* 31 2 2

→ i

U U RL RL

m m

  • (

) ( )

2

cot = −µ β

ij ij D D d RL

m A M