CLEO 3BELLE

1999

2001BTEV A

TLAS

?

19992008

Intensa atividade experimental

Além de dezenas de grupos experimentais pelo mundo …

Oscilações matéria – antimatéria

decaimento

Interações comuns ΔB=1 de trocade q (2/3) virtual t : dominant amplitude

ΔB=2

VtdΔmd

fB constante de decaimento BB Bag fator de “sacola”

mésons neutros B0 oscilamb

d

d

b

t

t

w- w-)()( dbBdbB dd

)()( sbBsbB ss

c

e-

eb

d

w-

d

Matriz de CKM

CKMV =

tbtstd

cbcscd

ubusud

vvv

vvv

vvv

=

fase de mistura

Fase do decaimento fraco

dd BB fase de mistura

ss BB

1

2/1

2/122

2

its

itd

iub

eVeV

A

eV

Os autoestados eletrofracos dos quarks são conectados aos estados de massa pelamatriz de CKM:

quatro parâmetrosA, λ, ρ, η

No MP:

03.02

No MP:

Triângulos de unitariedade

Vtd Vtb+Vcd Vcb

+Vud Vub= 0

(0,0)

Vub

Vcb

Vtd

(,)

(1,0)

Vtd Vud+Vts Vus

+Vtb Vub= 0

Vub

Vtd

Vts

• medir todos os ângulos• medir todos os lados MP: consistência!

violação de CP

Três manifestações possíveis de violação de CP:

Violação de CP direta (interferência entre duas amplitudes de decaimento)

Violação de CP indireta(interferência entre duas amplitudes de mistura)

Violação de CP na interferência entre decaimentos que oscilam (misturam) e entre decaimentos que não oscilam.

formalismo dependente do tempo

para Bd amplitude de decaimento para fBd

0BHfAf

0BHfAf evolução temporal

mtAimtAeetBHf fpq

f

timt

phys

21

2120 sincos)(

0B0B

CPf

CP violation: interference between mixing and decay

f

f

A

A

q

p

formalismo dependente do tempo para Bd

)()(

)()()(

tt

tttA

fBfB

fBfBCPf

Fábricas de b: Δt

mtAmtAtA mixdirCPf sincos)(

LHCb: t

1

12

2

dirA1

22

ImmixA

=0 B0→J/ψKS =+sin(2β)MP:

=0 =-sin(2β) B0→J/ψKL

Medindo β

b

d

d

W cc

s

0B /J

0K0K0B

b

dW

s

d

c

cg

u,c,t

/J

Decaimentos do tipo B0→J/ψKS e B0→J/ψKL

Bem entendidos na teoria: árvore and pinguin tem mesma fase

Experimento “relativamente simples”

ScScSd KKKB 1 ,,

Ld KJB

iCPe

2

1CP

1CP

medindo β

(D. Lange)

Fábricas de B : Belle, BaBar

colisores assimétricos em ee )( S4

nb 1bb-1-233 scm 103L

Um ano: ~ 100 M pares BB

Ldt Belle 132 fb-1

Março, 2003 BaBar 117 fb-1

Produção coerenteBB

KEKBLuminosidade alcançada:

1.06 x1034 cm-2s-1

Detetor Babar

Sumário de sin2b em b ccs

Já uma medida precisa: 7.5%05507340 .. Média mundial

rarer B decaysdccb

qqsb

Cabbibo supressed

b

d

d

W cc

d

0B /J

00Bb

dW

d

d

c

cg

u,c,t

/J

0B0 → J/ 0

B → KS B

b

d,u

W

ss

sg

Kd,u

bW

s

s

sg

u,c,t

Kd,u d,u

B

B → ‘ KS

Sensitive to new physics:• smaller amplitudes, NP through interf. terms• virtual particles (SUSY?) in penguin loops

not theoretically cleansmaller rates, higher back.

Same CKM structure as B0→J/ψKS

expect S=sin2β to 5%

B0 → J/ 0

S = - sin2β if no penguin C = 0 if no penguin

Measuring β in b→sss

Theoretical especulations

• sin(2β) = SϕK=-0.39 +- 0.41 (2.7 σ) from the SM prediction;

• models from SUSY could explain this result!G.L. Kane et al., PRL Apr.2003

Grossman et al. hep-ph/0303171

SM is alive and well!

Confidence levels in the large (rhobar,etabar) plane

obtained from the global fit. The constraint from the

WA sin2beta (from psi Ks modes) is overlaid.

Confidence levels in the large (rhobar,etabar) plane

obtained from the global fit. The constraint from the WA

sin2beta (from psi Ks modes) is included in the fit.

2007• More data close to theory limit from penguin pollution;• Measurement of ΔmS improve |Vtd/Vcb| from near cancellation of Bd and Bs form factor;• More data from B→hulν and B→hcX together with improvement in theory will give some improvement in |Vtd/Vcb| ;

)()(sin 2102 o

Strategy: new physics!

now

2007

1 yr

LHCb

BdJ/KS Bd

BsJ/ Bs DsK

statistics!!Goal: Physics beyond the Standard model

• Measurements which provide a reference case for SM effects;• Compare this to channels that might be affected by New Physics;• Understand experimental and theoretical systematics to a level where we can draw conclusions.

for larger the B boost increses rapidly

Hadronic b productionB hadrons at Tevatron

))2/ln(tan(

• b quark pair produced preferentially at low • highly correlated

tagging low pt cuts

LHCb Experiment

• Acceptance :– 15-300mrad

(bending)

– 15-250mrad (non-bending)

• Particle ID– RICH

detectors – Calorimeters– Muon

Detectors

• Dedicated B physics Experiment at the LHC– pp collisions at 14TeV

RICH1Z ~ 1.0-2.2 m

RICH2Z ~ 9.5-11.9 m

CalorimetersZ ~ 12.5-15.0 m

Muon SystemZ ~ 15.0-20.0 m

One event!

for the decay channelBs Ds +

Ds KKπ

Tracking performance

Average efficiency = 92 %Efficiency for p>5GeV >95%

Ghost rate pT>0.5 GeV ~ 7%.

Mass resolution Mass resolution (~13 MeV)(~13 MeV)

Momentum resolution:Momentum resolution:

p/p=0.38%

Proper timeProper time resolution (42 fs)resolution (42 fs)

<N> = 27 tracks/event <N> = 27 tracks/event

Hadron ID : Physics Performance

No RICH With RICH

n Signal Purity improved from 13% to 84% with RICH

n Signal Efficiency 79%

n RICH essential for hadronic decays

n Example : Bs K+K-

n Sensitive to CKM angle

Muon Identification

Muons selected by searching for muon stations hits compatible with reconstructed track extrapolations– Compare track slopes and distance of muon station hits

from track extrapolationFor P>3GeV/c

eff = 96.7 0.2 %

misid = 2.50 0.04 %

Measuring β Sod KJB

“gold-plated” decay channel at B-factories for measuring the Bd- Bd mixing phase needed for extracting γ from Bd ππ and Bs K K in SM Adir=0, non-vanishing value (~0.01) could be a signal of Physics Beyond SM precision measurement important

Inputs:

220 k/year signal194 k/year back.

Amix=sin(2β)=0.73

Adir = 0

0230.dirA

0220.mixA

ps

ACP(t)

Rare B decays

• flavour changing neutral currents only at loop level• very small BR ~ or smaller

In the SM:Excellent probe of indirect effects of new physics!

SB

SM : BR ~ • observation of the decay• measurement of its BR

910

510

CMS : 100 fb-1 (107s at 1034

cm-2s-1) ~ 26 signal events 6.4 events background

LHCb : 2 fb-1

~ 33 signal events ~ 10 events backgroundσM = 38 MeV

+-,

A. Ali et al., Phys. Rev. D61074024 (2000)

Rare B decays KBd

Forward-backward asymmetry

)(sAFB)( _ pps

can be calculated in SM and other models

BTeV data compared to Burdman et al calculation

Conclusions

LHCb and BTeV are second generation beauty CP violation experiments;

They are well prepared to make crucial measurements in flavour physics with huge amount of statistics;

Impressive number of different strategies for measurements of

SM parameters and search of New Physics;

CP violation is a cool research topic!!

B factories established CP violation in the B sector and are making interestingmeasurements;

Exciting times: understanding the origin of CP violation in the SM and beyond.