Motivation Loop-suppressed B meson decays can serve as sensitive - - PDF document

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Probing New Physics with B meson decays

b s Content: Motivation Quark flavor physics in the Standard Model Ulrich Uwer Experimental Status Flavor physics beyond the Standard Model LHCb Experiment B meson key measurements at the LHC

Motivation

Loop-suppressed B meson decays can serve as sensitive probes for New Physics:

New

W

New Physics

W

New Physics

W

Physics

Box Diagrams (Oscillation) Penguin Decays Additi l N Ph i lit d dif b l t t b t l h Heavy quark physics:

• Complementary to direct New Physics searches by ATLAS and CMS.
• Investigate the flavor structure of NP if found.

Additional New Physics amplitudes modify absolute rates but also phase dependent observables such as CP asymmetries: e.g. SUSY models

2

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Hitorical Examples

9

) ( ) (

− +

→ K BR

L

μ μ

K d

−

μ

W W

s

u

μ

ν GIM Mechanism: Observed branching ratio K0→μμ

9

10 ) 5 . 2 . 7 ( ) ( ) (

−

⋅ ± = → → all K BR K BR

L L

μ μ

+

μ

W

s

In contradiction with theoretical expectation in the 3-Quark Model Glashow, Iliopolus, Maiani (1970): Prediction of a 2nd up-type quark K0-K0 mixing:

c c c K K F K

sin cos m f m G m θ θ π = Δ

2 2 2 2 2

4 c , u c , u

+

W

−

W s

d

s d K K Gaillard, Lee and Rosner (1970++): From from K0-K0 mixing frequency: mc~1.5 GeV c quark was discovered only in 1974!

3

More Examples

ARGUS Experiment, 1987:

Observation of B0-B0 Oscillation

B B d b t

u c

td

V

∗ tb

V

mt > 50 GeV Discarded “top discovery”

B B b d v t

u c

td

V

∗ tb

V

Precision electro-weak Physics at the Z

+

e

−

e t t Z Z f f Prediction of top mass via radiative corrections G V

17

10 170

+

±

Discarded top discovery .

t GeV

17 19

10 170

+ −

± =

t

m After top discovery: Prediction of Higgs mass ) % ( CL GeV mH 90 144 <

4

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Why studying B mesons ?

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ d u ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ s c ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ b t

b quark:

• Heaviest quark that forms hadronic

bound states (m~4.7 GeV).

• Must decay outside 3rd family

⎠ ⎝ d ⎠ ⎝ s ⎠ ⎝ b

• Must decay outside 3

family

• All decays are CKM suppressed
• High mass: many accessible final

states (all Br’s are small)

• Long lifetime (~1.6 ps):

experimentally simple to identify

• Large CP violation expected

g p

Tree

• scillation

FCNC

5

B decays (for reference)

Dominant decays R h d i d

Semi-leptonic Hadronic

Rare hadronic decays Radiative and leptonic decays

Internal spectator Gluonic penguin W-exchange Radiative penguin

Radiative and leptonic decays

Electroweak penguin Electroweak box Annihilation 6

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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B meson physics

PDG 1986 PDG 2009

> 25 pages

1987 First observation of B0 mixing 1992 Evidence for

B Λ

1992 Evidence for 1993 First observation of , time resolved B mixing 1994 Evidence for , measurement of exclusive B lifetime 1998 Discovery of Bc 2001 Discovery of CPV in B system 2006 Measurement of Bs mixing

− +

→ → π π γ B K B ,

* s b B

, Λ

* *

, B

b

Ξ

7

Quark Flavor Physics in the Standard Model

• Mass generation and quark mixing
• Quark Mixing matrix
• Quark Mixing matrix
• CP Violation in the Standard Model
• Unitarity Triangle
• Comments on the baryon asymmetry

8

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Mass Generation in Standard Model

) , , ( ) , (

i a Higgs i a gauge SM

A A ψ φ ψ L L L + =

Standard Model Lagrangian:

u

q ⎟ ⎞ ⎜ ⎛

C.Jarlskog in “CP Violation”

. . L c h e Y L q Y Q q Y Q

R e L C u kR U jk jL d kR D jk jL Y

+ + + = φ φ φ

Yukawa couplings:

⎞ ⎛ + ⎞ ⎛

+

1 φ φ φ i

With Higgs doublet and its charge conjugate

L d j j jL

q q Q ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ = ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ + + = ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ =

+ 3 2 1

2 1 φ φ φ φ φ φ φ i i *

) (

φ σ φ φ φ

2

i

C

≡ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − =

− ∗

Needed to generate mass for up- type quarks. φ* does not transform as doublet under SU(2)

9

Symmetrie Breaking

Spontaneous symmetry breaking:

φ + = 2 υ φ

j

φ

3 2 1 , , = j

are eaten up

V(φ) φ ~ 246 GeV

2

v μ λ = −

2

{ }

φ) ( . . L

,

υ υ 1 1 2 + + + − = ∑

k j u kR U jk u jL d kR D jk d jl Y

c h q Y q q Y q

υ

U,D U,D

Y M =

u kR U jk u jL d kR D jk d jL

q M q q M q +

Non diagonal mass matrices:

6 GeV

μ

2 Y M =

Non-diagonal mass matrices: Diagonalization with help of unitary matrices:

) , , (

b s d D D R D D L

m m m Diag ≡ =

+

D U M U ) , , (

t c u U U R U U L

m m m Diag ≡ =

+

D U M U 1 UU =

+

Diagonalization possible with bi-unitary transformation

Daggers introduced for notational convenience

10

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Physical Quark Fields

R R L L R R R L L L R L kR jk jL

q D q q q q q q M q U U U U M U U M = = =

+ +

The physical fields (the one which correspond to the mass eigenstates) are:

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ = =

L L u L u L u L phys u L

t c u U q U q , ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ = =

L L d L d L d L phys d L

b s d U q U q , ⎟ ⎠ ⎜ ⎝

L

t ⎟ ⎠ ⎜ ⎝

L

b

{ }

K K + + + + + − = d d m c c m u u m

d c u phys Y

) φ ( L υ 1

→ 6 Dirac quark masses

11

Charged Current Interaction [ ] [ ]

. .

, ,

c h q U U q W i W c h q q W i W

phys d d u phys u d L u L

+ + − =

+ μ μ μ μ

γ γ

2 1 2 1

qd qu W expressed with physical quark fields

[ ] [ ]

. . . .

, , , ,

c h q q W i W c h q U U q W i W

phys d L CKM phys u L p y L L L p y L

+ − = + − = V

μ μ μ μ μ μ

γ γ

2 1

⎞ ⎛ ′ ⎞ ⎛ d V V V

b d

V

Quark mixing in CC described by VCKM

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ ′ ′ ⋅ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ ∝

+

b s d V V V V V V V V V

• t

, c , u J

tb ts td cb cs cd ub us ud

( )

μ μ

γ γ ) (

5

1

q p

Vpq

W

• In SM Yukawa interaction only source of Flavor Violation
• Masses and the mixing angles cannot be understood within SM

12

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Quark mixing & Flavor Violation

• In SM Yukawa interaction only source of Flavor Violation
• Masses and the mixing angles cannot be understood within SM
• Neutral current interaction is flavor conserving:

g

phys R phys R phys R R R phys R R R

q q q q q q ] [ ] [ ] [ K K K

μ μ μ

γ γ γ = = =

+

U U

Neutral current IA

1 U U =

+ R R

R R

R R

Flavor Changing Neutral Current (FCNC) processes can appear in the Standard Model only at loop-level:

K d

−

μ

+

μ s

13

Number of independent parameters: 18 parameter (9 complex elements)

• 5 relative quark phases (unobservable)
• 9 unitarity conditions

Parameters of CKM matrix

=4 independent parameters: 3 angles + phase

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ − ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ − ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ − = ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛

−

b s d c s s c c e s e s c c s s c b s d

i i

1 1 1 ' ' '

12 12 12 12 13 13 13 13 23 23 23 23 δ δ

PDG parametrization

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ − − − − − −

− 13 23 13 23 12 23 12 13 23 12 23 12 13 23 13 23 12 23 12 13 23 12 23 12 13 13 12 13 12

c c e s c s s c e s c c s s c s e s s s c c e s s c c s e s c s c c

i i i i i δ δ δ δ δ

ij ij ij ij

s c θ θ sin , cos where = = 3 Euler angles 1 Phase

12 13 23

, , θ θ θ δ

14

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Unobservable Phases

Phases of left-handed fields in JC are unobservable: possible redefinition

L u i L

u e u

) ( φ

→

L c i L

c e c

) ( φ

→

L t i L

t e t

) ( φ

→

L d i L

d e d

) ( φ

→

L s i L

s e s

) ( φ

→

L b i L

b e b

) ( φ

→

Real numbers Under phase transformation:

⎟ ⎟ ⎞ ⎜ ⎜ ⎛ ⎟ ⎟ ⎞ ⎜ ⎜ ⎛ ⎟ ⎟ ⎞ ⎜ ⎜ ⎛

− ) ( ) ( ) ( ) ( s i d i ub us ud c i u i

e V V V V V V e V

φ φ φ φ

⎟ ⎟ ⎟ ⎠ ⎜ ⎜ ⎜ ⎝ ⎟ ⎟ ⎠ ⎜ ⎜ ⎝ ⎟ ⎟ ⎟ ⎠ ⎜ ⎜ ⎜ ⎝ →

− − ) ( ) ( ) ( ) ( b i s i tb ts td cb cs cd t i c i

e e V V V V V V e e V

φ φ φ φ

j V j i j V α α φ φ α ))] ( ) ( ( exp[ − → ) , ( G f Lphys

invariant

) , ( H f L

affected, rephasing qR

15

Wolfenstein Parametrization

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ = b s d V V V V V V V V V

tb ts td cb cs cd ub us ud

⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ ' ' ' b s d

d s b u c t

( ) ( )

( )

4 2 3 2 2 3 2

1 1 2 1 2 1 λ λ η ρ λ λ λ λ η ρ λ λ λ O A i A A i A V V V V V V V V V V

tb ts td cb cs cd ub us ud CKM

+ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎜ ⎜ ⎝ ⎛ − − − − − − − = ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎝ ⎛ = λ, A, ρ, η with λ= 0.22

|Vub|×e-iγ |V | e-iβ

( )

( )

( )

( )

( )

( )

6 4 2 4 2 3 2 2 4 2 5 2 3 4 2

2 1 2 1 1 4 1 8 2 1 2 1 8 2 1 λ λ η ρ λ λ η ρ λ λ λ λ η ρ λ λ η ρ λ λ λ λ O A i A A i A A A i A i A VCKM + ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎜ ⎜ ⎜ ⎝ ⎛ − − − + − − − + − − − − + − − − − =

|Vtd|×e-iβ

16

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

9

Complex CKM elements and CP violation

L i

d

L j

u

ji

V

R i

d

R j

u

∗ ji

V CP

L j

u

L i

d

∗ ji

V T

CP (T) violation

∗

≠ ⇔

ji ji

V V

Remark: For 2 quark generations the mixing is described by the real 2x2

Cabbibo matrix → no CP violation !!. To explain CPV in the SM Kobayashi and Maskawa have predicted a third quark generation. i.e. Complex elements

17

Requirements for CP violation

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

2 2 2 2 2 2

− − −

u c u t c t

m m m m m m

CP Violation in the Standard Model

where Using parameterizations

( )( )( )

2 2 2 2 2 2

≠ × − − − ×

CP d s d b s b

J m m m m m m

{ }(

)

β α

α β β α

≠ ≠ = , Im

* *

j i V V V V J

j i j i CP

( )

Jarlskog determinant CP violation is small in the Standard Model

( )

5 2 6 13 23 12 23 13 12

10− = = = O A c c c s s s JCP η λ δ sin

18

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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CKM matrix is unitary : 12 conditions (6 normalisation, 6 orthogonality)

* * *

= + +

b d b d b d

V V V V V V

d bV

V *

d bV

V *

tb ubV

V *

td udV

V *

(db) ( t) (db)

Unitarity Triangles

* * * * * * * * * * * *

= + + = + + = + + + +

tb ub ts us td ud ts td cs cd us ud tb ts cb cs ub us tb td cb cd ub ud

V V V V V V V V V V V V V V V V V V V V V V V V (ut)

cd cbV

V *

ud ubV

V

td tbV

V

ts usV

V *

ub usV

V *

cb csV

V *

tb tsV

V *

tb cbV

V *

td cdV

V *

ts csV

V *

(db) (ut) (sb) (ct) (db) (sb) (ds)

All 6 triangles have the same area (= JCP/2 ): a measure of CPV in the Standard Model.

* * * * * *

= + + = + +

cb ub cs us cd ud tb cb ts cs td cd

V V V V V V V V V V V V (ct) (uc)

us udV

V *

ts tdV

V *

cs cdV

V *

cb ubV

V *

cd udV

V *

cs usV

V *

(ds) (uc)

19

Redraw “unsquashed” Δ’s and divide by

A 2nd Unitarity Triangle

V V V V V V

* tb td * cb cd * ub ud

= + +

Im

cd cbV

V *

3 *

λ A V V

ud ub

Re

α γ β

1

3 *

λ A V V

td tb

*V

V

cd cb

η

(db)

ρ,η

( )≡ 1− λ2 2

( ) ρ,η

( )

3

λ A

cd cb

ρ

α ≡ π − β − γ β ≡ arg −Vcb

*Vcd

Vtb

*Vtd

⎡ ⎣ ⎢ ⎤ ⎦ ⎥ = tan−1 η 1− ρ ~ 21o γ ≡ arg −Vub

*Vud

Vcb

*Vcd

⎡ ⎣ ⎢ ⎤ ⎦ ⎥ = tan−1 η ρ ~ 70o

20

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

11

Unitarity Triangle from B Decays

Im

&

β α γ

Re

&

u b →

21

Sides from CP conserving observables

c b →

Unitarity Triangle from B Decays

ρρ ρπ ππ , , : CPV

0 →

B

Im

Angles from CP β α γ

Re

Angles from CP violating observables

22

/ : CPV

S

K J B ψ →

KK K D B D K DK DK B

s s s

, , , , : CPV

* ) (

→ →

∗

π π

„Golden channel“ Very rare decays → several 109 B mesons necessary

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

12

The 2nd Unitarity Triangle

α

η

*V

V

*V

V

d d

V V V V V V

* tb ub * ts us * td ud

= + +

Im (ut)

ηλ2

Re

β−βs

ρ

βs γ+βs

3

λ A V V

tb ub 3

λ A V V

td ud

3 *

λ A V V

ts us

2 2

1 ρλ λ + −

λ A

2 1 ρλ +

βs ≡ arg −Vcb

*Vcs

Vtb

*Vts

⎡ ⎣ ⎢ ⎤ ⎦ ⎥ ~ ηλ2 ~ 1o

23

Standard Model & Baryon-Asymmetry

Sacharow Conditions:

• Baryon number violation

Explains the Standard Model the Baryon-Asymmetry of the Universe ?

• Baryon number violation
• C und CP violation
• Deviation from thermal equilibrium
• CP Violation in quark sector by faktor ~1010 too small.
• For MHiggs> 114 GeV: Symmetry breaking = 2nd order phase transition

Attractive: SUSY extensions of the Standard Model

• Additional CP Violation
• extended Higgs-Sector→ strong phase transition

Most attractive alternatives: Lepto-Baryogenesis

24

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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Experimental Status

f

• e+ e- B factories
• Measurement B0 B0 oscillation
• Measurement of CP Violation in B0→J/ψKs
• UnitarityTriangle

25

e+ e- B factories

e+ e+ → ϒ (4s) → B B σ (e+ e+ )

GeV 58 10. s =

pair is produced in a coherent L=1 state two B mesons evolve until one decays

B B B B

− +B

B B B / % / % 50 50

nb .1 1 =

b b

σ nb ~ Continuum 3

1.1 million / fb-1

26

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

14

Asymmetric beam energy

GeV 58 . 10 ECMS =

50% / 50%

GeV 3 . 5 −

e

+

e

B mesons at rest → Zerfallslänge z≈0

GeV 3 . 5

Symmetric: GeV 9 −

e

+

e

GeV 1 . 3 Boost β = 0.56

t c z βγ =

Asymmetric: decay length z≈250μm

27

Asymmetric B factories

PEP-II @ SLAC

High Energy Ring : 9.0 GeV e- Low Energy Ring : 3.1 GeV e+ Design luminosity : 3 x 1033 cm-2s-1

KEK-B @ KEK

High Energy Ring : 8.0 GeV e- Low Energy Ring : 3.5 GeV e+ Design luminosity : 1 x 1034 cm-2s-1 Design luminosity : 3 x 1033 cm 2s 1 Peak luminosity : 1.207 x 1034 cm-2 s-1 Design luminosity : 1 x 1034 cm 2s 1 Peak luminosity : 1.71 x 1034 cm-2 s-1 Beam crossing angle : 22 mrad

28

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

15

BABAR Kollaboration

BABAR Kollaboration 11 Länder 80 Institute 600 Physiker

29 30

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

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31

Mixing Phenomenology

B B

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ − = ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ) ( ) ( ) ( ) ( t B t B i t B t B dt d i 2 Γ M

Mass eigenstates:

L L L

m B q B p B Γ + =

,

with

No mass eigenstates

32

H H H

m B q B p B Γ − =

,

with

t t im L H L H

L H L H

e e B t B

, ,

) ( ) (

, , Γ − −

⋅ ⋅ =

2 1

Flavor eigenstates: ) ( ) (

H L H L

B B q B B B p B − = + = 2 1 2 1

complex coefficients

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

17

Mixing of neutral mesons

( )

[ ]

mt e e e B B P B B P

t t t

H L H L

Δ + + = → = →

Γ + Γ − Γ − Γ −

cos 2 4 1 ) ( ) (

2 /

CPT

( )

[ ]

( )

[ ]

mt e e e q p B B P mt e e e p q B B P

t t t t t t

H L H L H L H L

Δ − + = → Δ − + = →

Γ + Γ − Γ − Γ − Γ + Γ − Γ − Γ −

cos 2 4 1 ) ( cos 2 4 1 ) (

2 / 2 2 / 2

L H

m m m − = Δ

CP , T- violation in mixing:

1 ) ( ) ( ≠ ⇒ → ≠ → p q B B P B B P

33

B0-B0 Mixing

0 6 0,8 1 1,2

( )

mt e B B P

t

Δ + Γ = →

Γ −

cos 1 2 1 ) (

L H

m m m − = Δ

) (mit Γ Γ Γ

L H

≈ ≈

0,2 0,4 0,6 2 4 6 8 10

) cos 1 ( 2 1 ) ( mt e B B P

t

Δ − Γ = →

Γ −

0,5 1 1,5

) (

L H

m Δ π

Oscillation

• 1,5
• 1
• 0,5

1 2 3 4 5 6 7 8 9 10 B

t τ ) ( ) ( ) ( ) ( B B P B B P B B P B B P → + → → − →

B

t τ / Frequency

34

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

18

Standard Model Prediction

B B b d d v b t t

u c u c

td

V

∗ tb

V

01 55 ±

d d

B B −

td

V

∗ tb

V

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ = Δ

∗ 2 2 2 2 2 2 2

) ( 6

W t B W tb td B B B F d

m m F m V V B f m G m η π

e.w. correction

2 2 2

) 12 33 235 ( MeV B f

B B

± ± =

NLO QCD

01 . 55 . ± =

B

η

from lattice QCD s

B

s

B b s s b t t

ts

V

∗ tb

V

ts

V

∗ tb

V

2

) ( ~

tb ts s

V V m

∗

Δ

s s

B B −

35

Steps of oscillation measurement

B Mass & Vertex Reconstruction

ν

−

μ

Sig

B

) 4 ( s Υ

+ ∗

D

−

l

−

K

Sig tag

B

m z μ 250 ≈ Δ

B

Start / Stop Tagging Quality: Q = 30.5% B-flavor Tagging & Vertex Reconstruction Δt measurement

B

36

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

19

perfect tagging & Δt resolution realistic tagging & Δt resolution

B0 Oscillation

tagging & Δt resolution gg g unmixed mixed mixed unmixed

37

B0 Oscillation

1

0 774

d

m Δ π

d d

B B −

• 1

ps 004 . 006 . 506 . ± ± = Δ

d

m

B

0.774 τ ≈

(BABAR mean value March 2006)

• 1

ps ) syst. ( 07 . ) stat. ( 10 . 77 . 17 ± ± = Δ

s

m

B

26 τ ≈

(CDF Collaboration, September 2006)

s s

B B −

38

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Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

20

Observation of CP violation

1

A B f B →

1

A f B → f B

δ φ i i

e e A

CP

2

CP

f B

δ φ i i

e e A

CP

− 2

) cos( 2

2 1 2 2 2 1 2

δ φ + + + =

CP

A A A A A

CP

) cos( 2

2 1 2 2 2 1 2

δ φ − + + =

CP

A A A A A

39

„Golden“ Decay B0→J/ψKs

s

K J B ψ /

0 → s

K J B ψ /

0 →

CP

V V

ηCP=-1 B

b

d

c c s

cb

V

cs

V

s

K K →

ψ / J B

b

d

c c s

cb

V

cs

V

s

K K →

ψ / J

td

V

tb

V

B B b d d v b t t

u c u c

td

V

tb

V

Mixing Phase:

β φ 2 i i

e e

d =

40

SLIDE 21

Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

21

„Golden“ Decay B0→J/ψKs

s

K J B ψ /

0 →

A

CP

ηCP=-1 s

K J B ψ /

0 →

A

2 π i

e A ~

β 2 i

e

s

K J ψ /

B B

) sin( β 2 sin ) )( / ( ) )( / ( ) )( / ( ) )( / ( ) ( mt t K J B t K J B t K J B t K J B t A

s s s s CP

Δ = → Γ + → Γ → Γ − → Γ = ψ ψ ψ ψ

) )( / ( t K J B

s

ψ → Γ ) )( / ( t K J B

s

ψ → Γ

≠

41

CP Violation in B0→J/ψKs

b d B0 mixing b c c s W+ B0 decay K0 mixing s d

ccK0 channels

1 − =

CP

η

β

λ

i cd cb cd cb td tb td tb cd cs cd cs cs cb cs cb td tb td tb

e V V V V V V V V V V V V V V V V V V V V A A p q

2 * * * * * * * * * * CP −

− = − = − = =

d b p q / d s d

* cs cbV

V A ∝

d s

K K

p q /

β i

e p q

2

~

Same for all c cd cb td tb cd cs cs cb td tb

⇒ ≈

− β i td td

e V V

no direct CPV, no CPV in mixing

Beside Vtd all other CKM elements are real

β) sin(2 ) Im( 1 = =

CP CP

λ λ

42

SLIDE 22

Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

22

CP Violation in B0→J/ψKs

( )

( ) ( ) ( )

⎤ ⎡ + ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ Δ − + Δ − + × + ∝ → Γ

Δ − Δ −

t m t m e t f B

t d CP d CP CP CP t CP

B B

1 1 cos 2 1 sin Im 2 1 1 ) )( (

2 2 / 2 2 2 /

λ λ λ λ λ λ

τ τ

≠

( )

( ) ( ) ( )

⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ Δ − − Δ + + × + ∝ → Γ t m t m e t f B

d CP d CP CP CP CP

B

cos 2 1 sin Im 2 1 1 ) )( (

2

λ λ λ λ

( ) ( ) [ ]

t m C t m S f t B f t B f t B f t B t A

d f d f CP CP CP CP CP

Δ − Δ = → Γ + → Γ → Γ − → Γ = cos sin ) ) ( ( ) ) ( ( ) ) ( ( ) ) ( ( ) ( negligible Time resolved

Interference = sin2β for B0→J/ψKS indicates direct CP violation if |q/p|≠1

2 2 2

1 1 1 Im 2

CP CP f CP CP f

C S λ λ λ λ + − = + = negligible

43

Steps of the CP measurement

B Meson & Vertex Reconstruction

+

π

+

μ

/ J ψ

−

μ

CP

B

) 4 ( s Υ

Now: CP eigenstate

−

l

−

K

Reconstruction

−

π

S

K

CP tag

B

m z μ 250 ≈ Δ

B

Start /Stop B-flavor Tagging & Vertex Reconstruction Δt measurement

B

44

SLIDE 23

Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

23

A fully reconstructed event

B0 → D*+ π-

fast

tag

B

→ D0π+

soft

→K-π+ →ψ(2S) Ks →

+

• →

+

• B0(Δt)

CP

B

45

Bei Δt=0 war BCP ein B0.

→ μ+μ- → π+π-

CP Asymmetry and sin2β

CP=-1 final states

Ntag

Purity

PRL 94, 161803.

B B Mio 227

Ntag

y J/ψ KS (KS→π+π-) 2751 96% J/ψ KS (KS→π0π0) 653 88% ψ(2S) KS (→π+π-) 485 87% ⎟c1 KS (KS→π+π-) 194 85% ηc KS (KS→π+π-) 287 74% Total 4370 92%

023 . 040 . 722 . 2 sin ± ± = β Example (Summer 2006)

46

SLIDE 24

Probing the High-energy Frontier at the LHC: Probing New Physic with B meson decays

24

Experimental Status

Constraints

• nly from loops

Within uncertainties loop-processes well described by SM. New Physics effects only appear corrections to leading SM terms.

47