LATTICE QCD AND FLAVOR PHYSICS Vittorio Lubicz OUTLINE OUTLINE 1. - - PowerPoint PPT Presentation

lattice qcd and flavor physics
SMART_READER_LITE
LIVE PREVIEW

LATTICE QCD AND FLAVOR PHYSICS Vittorio Lubicz OUTLINE OUTLINE 1. - - PowerPoint PPT Presentation

LATTICE QCD AND FLAVOR PHYSICS Vittorio Lubicz OUTLINE OUTLINE 1. Motivations for flavor physics 1. Motivations for flavor physics 2. Lattice QCD and quark masses 2. Lattice QCD and quark masses 3. CKM matrix 3. CKM matrix a) The Cabibbo angle


slide-1
SLIDE 1

LATTICE QCD AND FLAVOR PHYSICS

OUTLINE

1.Motivations for flavor physics 2.Lattice QCD and quark masses 3.CKM matrix

a) The Cabibbo angle and the first row unitarity test b) The Unitarity Triangle Analysis and CP violation OUTLINE

1.Motivations for flavor physics 2.Lattice QCD and quark masses 3.CKM matrix

a) The Cabibbo angle and the first row unitarity test b) The Unitarity Triangle Analysis and CP violation

INAUGURAL CONFERENCE September 19 - 21, 2005

Vittorio Lubicz

slide-2
SLIDE 2

2

1

MOTIVATIONS FOR FLAVOR PHYSICS

slide-3
SLIDE 3

3

Flavor physics is (well) described but not explained in the Standard Model:

  • Why 3 families?
  • Why the spectrum of quarks

and leptons covers 5 orders of magnitude? (mq∼ GF

  • 1/2…)
  • What give rise to the pattern
  • f quark mixing and the

magnitude of CP violation? A large number of free parameters in the flavor sector (10 parameters in the quark sector only, 6 mq + 4 CKM)

Flavor

slide-4
SLIDE 4

4

K K K K

x x sL

˜

dR

˜

g

˜

sL

˜

dR

˜

g

˜

Flavor physics is an open window on New Physics: FCNC, CP asymmetries,…

E.g.:

ΛK0-K0 ~ 100 TeV

The flavor problem:

New Physics must be very special !!

ΛNP >> ΛEWSB ~ O(1 TeV)

(5) (6 2 )

+

NP N i P i i i i i

SM eff

c c O O = + + Λ Λ

∑ ∑

L L

New Physics can be conveniently described in terms of a low energy effective theory: E.g. K0-K0 mixing:

slide-5
SLIDE 5

5

…… εK = 2.280 10-3 ± 0.6% ∆md = 0.502 ps-1 ± 1% sin(2β) = 0.687 ± 5%

EXPERIMENTS We need to control the theoretical input parameters at a comparable level

  • f accuracy !!

THEORY

DETERMINATION OF THE SM FLAVOR PARAMETERS

THE PRECISION ERA OF FLAVOR PHYSICS

Challenge for LATTICE QCD Challenge for LATTICE QCD

slide-6
SLIDE 6

6

2

LATTICE QCD AND QUARK MASSES

slide-7
SLIDE 7

7

QUARK MASSES CAN BE DETERMINED BY COMBINING TOGETHER A THEORETICAL AND AN EXPERIMENTAL INPUT. E.G.: ♦ BEING FUNDAMENTAL PARAMETERS OF THE STANDARD MODEL, QUARK MASSES CANNOT BE DETERMINED BY THEORETICAL CONSIDERATIONS ONLY. ♦ QUARK MASSES CANNOT BE DIRECTLY MEASURED IN

THE EXPERIMENTS, BECAUSE QUARKS ARE CONFINED INSIDE HADRONS

[MHAD(ΛQCD,mq)]TH. = [MHAD]EXP.

LATTICE QCD

slide-8
SLIDE 8

8

LATTICE DETERMINATION OF QUARK MASSES mq(µ) = mq(a) Zm(µa)

^

ADJUSTED UNTIL

MH

LATT = MH EXP

Extrapolation to m = mu,d Extrapolation to m = ms

PERTURBATION THEORY OR NON-PERTURBATIVE METHODS

slide-9
SLIDE 9

9

PERTURBATION THEORY

mq(µ) = mq(a) Zm(µa)

ADJUSTED UNTIL MH

LATT = MH EXP

SYSTEMATIC ERRORS

O(a) O(α2)

IMPROVED ACTIONS: NON-PERTURBATIVE RENORMALIZATION

SLATT = SQCD+ a S1 + a2 S2 + …

TWO IMPORTANT THEORETICAL TOOLS

slide-10
SLIDE 10

10

NON-PERTURBATIVE RENORMALIZATION THE RI-MOM METHOD NON-PERTURBATIVE RENORMALIZATION THE RI-MOM METHOD

ZO(aµ) ΓO (p2)|p2=µ2 = Γ Tree-Level

p p p p p p

O

= + + ...

ΓO (p2) The (non-perturbative) renormalization condition:

Several NPR techniques have been developed: Ward Identities, Schrodinger functional, X-space

slide-11
SLIDE 11

11

THE STRANGE QUARK MASS

ms (2 GeV ) = (105 ± 15 ± 20) MeV

V.Lubicz, plenary at Lattice 2000 T.Izubuchi, plenary at Lattice 2005

UNQUENCHED

[PDG 2002: ms= (120 ± 40) MeV]

2004

The highest values

  • btained with NPR
slide-12
SLIDE 12

12

THE AVERAGE UP/DOWN QUARK MASS

Good agreement with the ChPT prediction 2 ms/(mu+md)

From S. Hashimoto ICHEP 2004 RATIOS OF LIGHT QUARK MASSES ARE PREDICTED ALSO BY CHIRAL PERTURBATION THEORY:

= 24.4 ± 1.5

ms (mu + md)/2

= 0.553 ± 0.043

mu md

slide-13
SLIDE 13

13

3

CKM MATRIX

a) THE CABIBBO ANGLE AND THE “FIRST ROW” UNITARITY TEST

slide-14
SLIDE 14

14

PDG 2004 quotes a 2σ deviation from unitarity:

The most stringent unitarity test: |Vud|2 + |Vus|2 + |Vub|2 = 1

|Vud| = 0.9740 ± 0.0005 |Vud|2 + |Vus|2 + |Vub|2 - 1 = - 0.0029 ± 0.0015 |Vus| = 0.2200 ± 0.0026 |Vub| = 0.0037 ± 0.0005

SFT and neutron β-decay

K→πlν

(BNL-E865 + old exps)

b→u incl. and excl. ( |Vub|2 ≈ 10-5 )

BUT: the PDG average for |Vus| is superseded by NEW experimental and theoretical results

slide-15
SLIDE 15

15

Kl3: the NEW experimental results Kl3: the NEW experimental results

BNL-E865

PRL 91, (2003) 261802

NA48

PLB 602, (2004) 41

KTeV

PRL 93, (2004) 181802

Summer 2004

V

us f+

  • (0)

F.Mescia ICHEP ‘04 KLOE

hep-ex/0508027

slide-16
SLIDE 16

16

Kl3 theory Kl3 theory

2 5 3 2 2 2 2

192 ) ) ( (1

| | V | (0)

( ) |

F K ew K l K l

us

G M C I S

f

K l

π

π δ

γ π ν

+

⋅ ⋅ +

Γ → =

K π

s u d l v

Vus = λ

f+(0) = 1 + f2 + f4 + O(p8)

Vector Current Conservation

f2 = − 0.023

Independent of Li (Ademollo-Gatto) THE LARGEST UNCERTAINTY

“Standard” estimate:

Leutwyler, Roos (1984) (QUARK MODEL)

f4 = −0.016 ± 0.008

ChPT

f+(0) = 1 - O(ms-mu)2 Ademollo- Gatto: O(1%). But represents the largest theoret. uncertainty

slide-17
SLIDE 17

17

… and model estimates

C12 (µ) and C34 (µ) can be determined from the slope and the curvature

  • f the scalar form factor. But experimental data are not accurate enough

f4: the ChPT calculation…

f4 = ∆loops(µ) − [C12 (µ) + C34 (µ)] ( MK − Mπ ) 8 Fπ

4 2 2 2

Jamin et al., f4 = -0.018 ± 0.009 [Dispersive analysis]

LOC

Cirigliano et al., f4 = -0.002 ± 0.008 [1/Nc+Low resonance]

LOC

Leutwyler and Roos, f4 = -0.016 ± 0.008 [Quark model ]

LOC

Lattice QCD: VERY CHALLENGING

A PRECISION OF O(1%) MUST BE REACHED ON THE LATTICE !!

Post and Schilcher, Bijnens and Talavera

(µ = ???)

slide-18
SLIDE 18

18

1) Evaluation of f0(qMAX)

2

The first Lattice QCD calculation

The basic ingredient is a double ratio of correlation functions:

D.Becirevic, G.Isidori, V.L., G.Martinelli, F.Mescia, S.Simula, C.Tarantino, G.Villadoro. [NPB 705,339,2005] 1%

slide-19
SLIDE 19

19

LQCD: λ+ = ( 25 ± 2 ) 10-3 λ0= ( 12 ± 2 ) 10-3 KTeV: λ+= ( 24.11 ± 0.36 ) 10-3 λ0= ( 13.62 ± 0.73 ) 10-3 Comparison of polar fits:

2) Extrapolation of f0(qMAX) to f0(0)

2

LQCD PREDICTION !!

slide-20
SLIDE 20

20

f+ (0) = 0.960 ± 0.005 ± 0.007

K0π-

( In agreement with LR !! )

3) Extrapolation to the physical masses 3) Extrapolation to the physical masses

Preliminary unquenched results have been also presented

C.Dawson, plenary at Lattice 2005

slide-21
SLIDE 21

21

Summer 2004

V

us f+

  • (0)

f+(0) = 0.960 ± 0.009

|Vud|2 + |Vus|2 + |Vub|2 - 1 = - 0.0007 ± 0.0014

FIRST ROW UNITARITY FIRST ROW UNITARITY

Vus = 0.2250 ± 0.0021 [Vus·f+(0)]EXP = = 0.2250 ± 0.0021

slide-22
SLIDE 22

22

3

CKM MATRIX:

b) THE UNITARITY TRIANGLE ANALYSIS AND CP VIOLATION

slide-23
SLIDE 23

23

THE UNITARITY TRIANGLE ANALYSIS

1-λ2 λ A λ3(ρ-iη)

  • λ

1- λ2/2 A λ2 Aλ3(1- ρ-iη) -A λ2 1

VCKM ≈

CP violation

VudVub + VcdVcb + VtdVtb = 0 * * *

slide-24
SLIDE 24

24

THE UNITARITY TRIANGLE ANALYSIS

1-λ2 λ A λ3(ρ-iη)

  • λ

1- λ2/2 A λ2 Aλ3(1- ρ-iη) -A λ2 1

VCKM ≈

CP violation

VudVub + VcdVcb + VtdVtb = 0 * * * 5 CONSTRAINTS

Hadronic matrix elements from LATTICE QCD

f+,F(1),…

2 + 2

(b→u)/(b→c) ρ η

slide-25
SLIDE 25

25

THE UNITARITY TRIANGLE ANALYSIS

1-λ2 λ A λ3(ρ-iη)

  • λ

1- λ2/2 A λ2 Aλ3(1- ρ-iη) -A λ2 1

VCKM ≈

CP violation

VudVub + VcdVcb + VtdVtb = 0 * * * 5 CONSTRAINTS

Hadronic matrix elements from LATTICE QCD

f+,F(1),…

2 + 2

(b→u)/(b→c) ρ η

ξ

(1– )2 +

2

∆md/ ∆ms ρ η

fBd BBd

(1– )2 +

2

∆md ρ η

2

slide-26
SLIDE 26

26

THE UNITARITY TRIANGLE ANALYSIS

1-λ2 λ A λ3(ρ-iη)

  • λ

1- λ2/2 A λ2 Aλ3(1- ρ-iη) -A λ2 1

VCKM ≈

CP violation

VudVub + VcdVcb + VtdVtb = 0 * * * 5 CONSTRAINTS

Hadronic matrix elements from LATTICE QCD

f+,F(1),…

2 + 2

(b→u)/(b→c) ρ η

ξ

(1– )2 +

2

∆md/ ∆ms ρ η

fBd BBd

(1– )2 +

2

∆md ρ η

2

BK [(1–

) + P]

εK

η ρ

slide-27
SLIDE 27

27

THE UNITARITY TRIANGLE ANALYSIS

1-λ2 λ A λ3(ρ-iη)

  • λ

1- λ2/2 A λ2 Aλ3(1- ρ-iη) -A λ2 1

VCKM ≈

CP violation

VudVub + VcdVcb + VtdVtb = 0 * * * 5 CONSTRAINTS

Hadronic matrix elements from LATTICE QCD

f+,F(1),…

2 + 2

(b→u)/(b→c) ρ η

ξ

(1– )2 +

2

∆md/ ∆ms ρ η

fBd BBd

(1– )2 +

2

∆md ρ η

2

BK [(1–

) + P]

εK

η ρ A(J/ψ KS)

sin2β(ρ, η)

slide-28
SLIDE 28

28

Vub and Vcb from semileptonic decays

slide-29
SLIDE 29

29

Vub and Vcb from semileptonic decays

UNQUENCHED QUENCHED

B π

b u d l v

Vub

Γ(B→ πlv) = ∫dq2 λ(q2)3/2 |f+( q2)|2

192 π3 GF

2|Vub|2

slide-30
SLIDE 30

30

K–K mixing: εK and BK

slide-31
SLIDE 31

31

K–K mixing: εK and BK

K K

^ BK= 0.79 ± 0.04 ± 0.09

From S. Hashimoto ICHEP 2004

QUENCHED

slide-32
SLIDE 32

32

K–K mixing: εK and BK

LATTICE PREDICTION (!)

BK = 0.90 ± 0.20 [Gavela et al., 1987]

^

K K

^ BK= 0.79 ± 0.04 ± 0.09

From S. Hashimoto ICHEP 2004

QUENCHED

slide-33
SLIDE 33

33

Bd and Bs mixing: fB√BB

slide-34
SLIDE 34

34

Bd and Bs mixing: fB√BB

fBs√BBs= 276 ± 38 MeV, ξ = 1.24 ± 0.04 ± 0.06

From S. Hashimoto

ICHEP 2004

slide-35
SLIDE 35

35

Sin2β = 0.734 ± 0.024

α = (98.2 ± 7.7)o

UT-FIT RESULTS UT-FIT RESULTS

η = 0.343 ± 0.028

Collaboration

[JHEP 0507 (2005) 028]

γ = (57.9 ± 7.4)o ρ = 0.214 ± 0.047

slide-36
SLIDE 36

36

Sin2βUT Sides = 0.793 ± 0.033 Sin2βJ/ψ Ks = 0.687 ± 0.032 3 FAMILIES:

  • Only 1 phase
  • Angles from

the sides

INDIRECT EVIDENCE OF CP A CRUCIAL TEST OF THE SM

slide-37
SLIDE 37

37

Sin2βUT Sides = 0.793 ± 0.033 Sin2βJ/ψ Ks = 0.687 ± 0.032

Prediction (Ciuchini et al., 2000):

Sin2βUTA = 0.698 ± 0.066 3 FAMILIES:

  • Only 1 phase
  • Angles from

the sides

INDIRECT EVIDENCE OF CP A CRUCIAL TEST OF THE SM

slide-38
SLIDE 38

38

PREDICTION FOR ∆ms

∆ms = (22.2 ± 3.1) ps-1

DIRECT MEASUREMENT: ∆ms > 14.5 ps-1 @ 95% C.L.

slide-39
SLIDE 39

39

LATTICE QCD vs UT FITS

1.24 ± 0.04 ± 0.06 276 ± 38 MeV 0.79 ± 0.04 ± 0.09 0.69 ± 0.10 265 ± 13 MeV 1.15 ± 0.11 fBs√BBs ξ BK ^ Lattice QCD UT Fits

slide-40
SLIDE 40

40

15 YEARS OF (ρ-η) DETERMINATIONS 15 YEARS OF (ρ-η) DETERMINATIONS

Such a progress would have not been possible without LATTICE QCD calculations !!