Observation of Bs mixing - Fermilableonardo/docs/seminar_cern.pdf · 2015-11-17 · N. Leonardo,...

Observation of Bs mixing

N. LeonardoCERN

CERN SeminarApril 16, 2007

N. Leonardo, CERN-PH CERN Seminar

Flavor Oscillations• described by basic quantum mechanics

• two-state system: ⎨B, B⎬• H = H0 + HΔB

‣ diagonalize Hamiltonian

• mass eigenstates: ⎨BH, BL⎬‣ separately evolve in time

• mass difference

Δm = mH - mL

determines oscillation frequency of the system

0

0.2

0.4

0.6

0.8

0 1 2 3 4 5proper decay time, t [ps]

Prob

abilit

y De

nsity

unmixedmixedtotal

P(B → B̄) ∼e−t/τ

2τ(1 − cos ∆m t)


In the Standard Model• Mixing occurs via 2nd order flavor changing weak transitions

• Ratio of Bs0 and Bd0 oscillation frequencies

allows precise determination of CKM elements‣ Δmd measured to high precision‣ Δms had not been measured

∆ms

∆md

=mBs

mB0

ξ2|Vts|2

|Vtd|2

t!

t(c, u)

(c!, u!)W+ W"

s!

b

b!

s

Bs Bs

Vts

Vts

∆mq ∝ |Vtq|2

➠


η̄ = (1 − λ2/2) ηρ̄ = (1 − λ2/2) ρ

Flavor Parameters CKM matrix

• CKM matrix unitarity condition

may be represented as a triangle in complex plane

‣ in terms of re-scaled ρ and η parameters

0*** =++ tbtdcbcdubud VVVVVV

Wolfenstein parameterization

Cabibbo-Kobayashi-Maskawa matrix

V =

Vud Vus Vub

Vcd Vcs Vcb

Vtd Vts Vtb

=

1 − λ2/2 λ Aλ3(ρ − iη)

−λ 1 − λ2/2 Aλ2

Aλ3(1 − ρ − iη) −Aλ2 1

+O(λ4)~u

d

c

t

s b


!

0 0.5 1

"

0

0.5

Δmd

!

0 0.5 1

"

0

0.5

The Beauty Unitarity Triangle

!

0 0.5 1

"

0

0.5

/ ΔmsΔmd


Full UT/CKM Fit

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

-0.4 -0.2 0 0.2 0.4 0.6 0.8 1

!

"md

#K

$ "ms & "md

|Vub/Vcb|

sin 2%

sol. w/ cos 2% < 0(excl. at CL > 0.95)

!

%$

&

'

excl

uded

are

a ha

s C

L > 0.

95 C K Mf i t t e r

EPS 2005

Before Δms measurement


History a 20 year quest

1987 first evidence of B0 mixing by UA1 followed by observation of B0 mixing by Argus 1989 CLEO confirms Argus results1990s inclusive B mixing measurements from LEP establish Bs mixing1993" first time dependent measurements of Δmd by ALEPH" first lower limit on Δms by ALEPH1999" CDF Run I result on Δms: Δms>5.8 ps-1

2005" D∅ first result Δms: Δms>5.0 ps-1

" CDF Run II first results Δms: Δms>7.9 ps-1

2006" D∅ reports interval: Δms ε [17,21] ps-1 at 90% CL

CDF Run II first measurement

PLB 186, 247 (1987)

PLB 192, 245 (1987)

PRL 62, 2233 (1989)

PLB 313, 498 (1993)

PLB 322, 441 (1994)

PRL 82, 3576 (1999)

PRL 97, 021802 (2006)

PRL 97, 062003 (2006)Δms = 17.31 ± 0.07 ps-1- 0.18+0.33


0.35 0.4 0.45 0.5 0.55 0.6 0.65

!md (ps-1)

World averagefor PDG 2006

0.507 ±0.005 ps-1

CLEO+ARGUS("d measurements)

0.494 ±0.032 ps-1

Average of 27 above 0.507 ±0.005 ps-1

BABAR D*l#/l,K,NN(23M BB$ )

0.492 ±0.018 ±0.013 ps-1

BABAR D*l#(part)/l(88M BB$ )

0.511 ±0.007 ±0.007 ps-1

BELLE B0d(full)+D*l#/comb

(152M BB$ )0.511 ±0.005 ±0.006 ps-1

BELLE l/l(32M BB$ )

0.503 ±0.008 ±0.010 ps-1

BELLE D*%(part)/l(31M BB$ ) 0.509 ±0.017 ±0.020 ps-1

BABAR l/l(23M BB$ )

0.493 ±0.012 ±0.009 ps-1

BABAR B0d(full)/l,K,NN(32M BB$ ) 0.516 ±0.016 ±0.010 ps-1

CDF1 D*l/l(92-95)

0.516 ±0.099 +0.029 ps-10.516 ±0.099 -0.035

CDF1 l/l,Qjet(94-95)

0.500 ±0.052 ±0.043 ps-1

CDF1 µ/µ(92-95)

0.503 ±0.064 ±0.071 ps-1

CDF1 Dl/SST(92-95)

0.471 +0.078 ±0.034 ps-10.471 -0.068

OPAL %*l/Qjet(91-00)

0.497 ±0.024 ±0.025 ps-1

OPAL D*/l(90-94)

0.567 ±0.089 +0.029 ps-10.567 ±0.089 -0.023

OPAL D*l/Qjet(90-94) 0.539 ±0.060 ±0.024 ps-1

OPAL l/Qjet(91-94)

0.444 ±0.029 +0.020 ps-10.444 ±0.029 -0.017

OPAL l/l(91-94) 0.430 ±0.043 +0.028 ps-10.430 ±0.043 -0.030

L3 l/l(IP)(94-95)

0.472 ±0.049 ±0.053 ps-1

L3 l/Qjet(94-95)

0.437 ±0.043 ±0.044 ps-1

L3 l/l(94-95)

0.458 ±0.046 ±0.032 ps-1

DELPHI vtx(94-00)

0.531 ±0.025 ±0.007 ps-1

DELPHI D*/Qjet(91-94)

0.523 ±0.072 ±0.043 ps-1

DELPHI l/l(91-94)

0.480 ±0.040 ±0.051 ps-1

DELPHI %*l/Qjet(91-94) 0.499 ±0.053 ±0.015 ps-1

DELPHI l/Qjet(91-94)

0.493 ±0.042 ±0.027 ps-1

ALEPH l/l(91-94) 0.452 ±0.039 ±0.044 ps-1

ALEPH l/Qjet(91-94)

0.404 ±0.045 ±0.027 ps-1

ALEPH D*/l,Qjet(91-94)

0.482 ±0.044 ±0.024 ps-1

Heavy FlavourAveraging Group

B mixing status

Δms>14.4 ps-1 at 95%CL sensitivity 18.2 ps-1

[prior to Tevatron Run II results]

-6 -4 -2 0 2 4

amplitude at !ms = 15.0 ps-1

Average for PDG 2006 0.48 ± 0.43

amplitude

(18.2 ps-1)

(sensitivity)

CDF1 l"/l(92-95)

-0.14 ± 2.00 ± 0.51 ( 5.1 ps-1)

SLD dipole(96-98)

0.44 ± 1.00 + 0.44 0.44 ± 1.00 - 0.28 ( 8.7 ps-1)

SLD Ds(96-98) 1.03 ± 1.36 + 0.31 1.03 ± 1.36 - 0.31 ( 3.3 ps-1)

OPAL Dsl(91-95)-3.63 ± 3.05 + 0.40-3.63 ± 3.05 - 0.42 ( 4.2 ps-1)

OPAL l(91-95)

-1.25 ± 2.34 ± 1.91 ( 7.2 ps-1)

DELPHI l(92-00)

-0.96 ± 1.35 ± 0.71 ( 9.1 ps-1)

DELPHI vtx(92-00)

-0.23 ± 3.04 ± 0.56 ( 6.9 ps-1)

DELPHI Dsl+"l(92-95)

1.25 ± 1.37 ± 0.31 ( 8.6 ps-1)

DELPHI Bs+Dsh(92-95) 0.45 ± 3.58 ± 1.93 ( 3.2 ps-1)

ALEPH Bs(91-00)-0.47 ± 1.15 ± 0.47 ( 0.4 ps-1)

ALEPH Dsl(91-95) 3.83 ± 1.49 ± 0.32 ( 7.5 ps-1)

ALEPH l(91-95, no Dsl, adjusted)

0.50 ± 0.79 ± 0.16 (13.1 ps-1)

Heavy FlavourAveraging Group

CD

F I

SLD

LE

P

BA

BA

R, B

ELLE

CD

F 1

LEP

Δmd = 0.507 ± 0.005 ps-1


Scope & Overview

DetectorCDF, D∅

Data Analysis

Amplitude ScanΔmS

CKM Fit

Standard ModelFlavor Models

pp collisionsTevatron

-

Trigger Unbinned

Likelihood Fitter

B flavor tagging

B proper decay timeB mass

B lifetime τB0 mixing Δmd

tag calibration

likelihood model

MCsimulation

σpp→bb--


Final State Reconstructionb-flavor at decay

Proper Decay TimeIn B rest frame

Trigger SideOpposite Side

Analysis Ingredients

b-Flavor Taggingb-flavor at production

/ l+

oppositeside kaon

K-


proper decay time, t [ps]0.0 0.5 1.0 1.5 2.0

prob

abili

ty d

ensi

ty

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

(ideal scenario)

total

mixed unmixed

Realistic Effects oscillation dampening

proper decay time, t [ps]0.0 0.5 1.0 1.5 2.0

prob

abili

ty d

ensi

ty

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

(realistic scenario)

total

mixed unmixed

σA =

√2

εD2

√B + S

Se(∆m σt)

2/2

resolution of mixing signal

• signal yield, S

• purity, S/B

• flavor tagging power, εD2

• proper time uncertainty, σt

‣ decay-length resolution

‣ effective momentum resolution

Getting the Data


Tevatron Collider

1km

CDF D∅

Tevatron

Main Injector

√s = 1.96 TeV

@Fermilab


protons

antiprotons

Electronics

Tracker Solenoid Magnet

3 LayerMuon System

Preshowers

CDF and D∅ Detectors

Key features for Δms

momentum and vertexing resolutionparticle identification‘deadtimeless’ trigger system


Triggering on Displaced Tracks

• heavy flavor decays displaced from the primary vertex

‣ daughter tracks tend to have large impact parameter

• trigger on displaced tracks‣ pT>2GeV/c, 120μm<|d0|<1mm

• requires precision tracking in silicon detector (SVT)

!600 !400 !200 0 200 400 6000

2000

4000

6000

8000

10000

12000

14000

16000

18000

m)µ (0SVT d

25!SVT2" 2 GeV/c; #tP

m Includes

beamspot33 mµ µ = 47 $

mµ

track

s pe

r 10

Secondary VertexPrimay Vertex B

.impactparameter

d0

CDF Run II

N. Leonardo, MIT September 21st, 2006

B meson samples• collect large data samples of B mesons:

B+, B0, Bs

• fully reconstructed decays ‣ all B decay products are reconstructed‣ complete event information ⇒ superior resolutions‣ smaller yields

• partially reconstructed decays‣ some decay products are missed: eg neutrinos‣ partial event information ⇒ poorer resolution‣ large yields


Signal and Control Samples• Signal samples

‣ hadronic:

‣ semileptonic:

• Calibration and validation samples

• Sample to tune flavor taggers (largest)‣ inclusive lepton + displaced track sample

Bs → D−

sπ

+(π+π−)

Bs → D−

sl+X

with D−

s → φπ−,K∗0K

−, π+π−π−

Bs → J/ψφ

8.7k (CDF)

50k(D∅), 61.5k (CDF)

300k(D∅),900k (CDF)

B+→ J/ψK+, D̄0π+(π+π−)

B0→ J/ψK∗0, D−π+(π+π−), D∗−π+(π+π−)

B+,0→ D̄0l+X, D−l+X, D∗−l+X

50k (CDF)

60k (CDF)

with D∗−→ D0

π−

,D0→ K−

π+(π+

π−),D−

→ K+π−

π−


Hadronic samples

• fully reconstructed peak

‣ ‘golden mode’ (narrow Φ, low comb. bkg)

• partially reconstructed‣double signal yield‣soft ϒ and π0 lost‣but nearly fully reconstructed

(fraction of rec’d pT ~96%)

0sB

−sD

+π+W

b cd

s

u

s

]2) [GeV/c!,!"mass(5.2 5.4 5.6 5.8

2ca

ndid

ates

per

10

MeV

/c

0

100

200

300

400

data

fit+/K+! -

s D# s B+$-s D# s B

+/K+!*-s D# s B

X-s D# b

+! - D# 0 B-! +

c% # b%

comb. bkg.

]2) [GeV/c!,!"mass(5.2 5.4 5.6 5.8

-1CDF Run II L = 1 fb

Bs → D−

sπ+, D−

s→ φπ−


] [GeV!(KK)M

)Ev

ents

/(0.0

1 G

eV

0 0

400

800

1200

2000

4000

6000(a) (b)

D Run II 1 fb"1 1 fb"1D Run II

1.8 1.9 2.0] [GeV

!(KK)M1.8 1.9 2.0

D∅ Run II L =1 fb-1

Semileptonic samples0sB

−sD

+W

b clν

s

+l

s

]2 mass [GeV/c--l+! "

3 4 5

2ca

ndid

ates

per

35

MeV

/c

0

500

1000

1500

2000 data fit

signal0sB

false lepton & physics comb. bkg.

]2 mass [GeV/c--l+! "

3 4 5

]2 mass [GeV/c+! "1.94 1.96 1.98 2.00

2ca

nd. p

er 1

MeV

/c

0

1000

2000

3000

4000

]2 mass [GeV/c+! "1.94 1.96 1.98 2.00

CDF Run II L =1 fb-1

partial reconstruction, limited resolution, large yields

Proper Decay Time B Lifetime measurement


Proper Decay Time

Life

time

effic

ienc

y

0

0.5

1

1.5

21!1f1"

2!2f2"3!3f3"

4!4f4"

0.00179 0.00150 0.06806 0.01322 0.08388 0.02725 0.01218 0.68894 0.00757 0.00755 0.22568 0.00839

/ NDF = 105.02 / 107, Prob = 56.34%2#

Proper decay length [cm]0 0.1 0.2 0.3 0.4

$(d

ata

- fit)

/

-2

0

20.20 0.4

proper decay distance [cm]

Decay time in B rest frame: t = L m/p

t-distribution determined by

• B meson lifetime

• decay distance resolution

• trigger/selection sculpting

‣ trigger (SVT) requirements on |d0| and event selection criteria on LT

modify PDF shape‣ described by t-efficiency function

from Monte Carlo, εt(t)

production vertex

B decay position

t-efficiency ε(t)

L

P(t) ∝ e−t′/τ ⊗ R(t − t

′;σt) · E(t)


proper time [cm]-0.2 -0.1 0.0 0.1 0.2

mµ

cand

idat

es /

20

10

210

310

410 data+! - D

fit+ f

++ f prompt

proper time [cm]-0.2 -0.1 0.0 0.1 0.2

CDF Run II Preliminary

proper time, ct [cm]

Calibrating Resolution on Data

• use large prompt D meson sample to construct B-like topologies of prompt D+track

• compare reconstructed decay point to interaction point• calibrate t-resolution by fitting prompt t-distribution

prompt track

Ds- vertex

P.V.“Bs” vertex


• fully rec’d Bs→Ds(3)π :σl ~ 26 μm (87 fs)σp/p <1%

• partially rec’d Bs→Ds*π, Dsρ :σl ~ 29 μm (97 fs)σp/p ~2%

• semileptonic Bs→DslX :• σl ~ 30-70 μm (100-230 fs)• σp/p ~3-20%

Proper time resolution

sBT/pReconstructed

T = p!0.4 0.6 0.8 1.0

proba

bility

dens

ity

5

10" l (*)

s D# 0sBall

2 3.1 GeV/c$ lsD 2.0 < m2 4.5 GeV/c$ lsD 4.3 < m2 5.1 GeV/c$ lsD 4.9 < m

% *s D# 0

sB& s D# 0

sB

CDF Run II

sBT/pReconstructed

T = p!0.4 0.6 0.8 1.0

Proper decay time [ps]0 1 2 3

Prop

er de

cay t

ime r

esolu

tion [

fs]

0

200

400

600

800

-1Osc. / 18 ps

! s D" 0sB

# s / D! *s D" 0

sB

2 5.1 GeV/c$ lsD, 4.9 < m% l (*)s D" 0

sB

2 4.5 GeV/c$ lsD, 4.3 < m% l (*)s D" 0

sB

2 3.1 GeV/c$ lsD, 2.0 < m% l (*)s D" 0

sB

CDF Run II

σt = σl ⊕ t ·σp

p

P(t) !→ P(κt) ⊗κ F(κ)


Lifetime Fits

Consistent with World Average: τ(Bs) = 1.461 ± 0.057 ps

proper time [cm]0.0 0.2 0.4

mµ

cand

idat

es p

er 3

0

1

10

210

310 data

fit+! (3)-

s D" s B

random bkg.+! (3)- D" 0 B-! (3)+

c# " b#


CDF Run II Preliminary -1 1 fb$L

proper time, ct [cm] Pseudo Proper Decay Length (cm)-0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5mµ

Can

did

ate

s p

er

50

-110

1

10

210

310

/dof = 1.062!

-1DØ, 0.4 fb

proper time, ct [cm]

D∅ Run II L = 0.4 fb-1

Bs→DslX

τ(Bs) = 1.54± 0.04 (sta.) ps τ(Bs) = 1.398 ± 0.052 ps

b Flavor Tagging Δmd measurement


Tagging B Production Flavor

• produced B(b) or B(b)?

• use combined flavor taggers

‣ Opposite side (OST)

‣ Same side (SST)

• quantify performance with‣ efficiency, ε ≡ fraction of tagged events‣ dilution, D ≡ 1 - 2 × mistag probability‣ effective statistics for mixing becomes

N ➟ N εD2

K!

Bs

SST

OSTa l!

b K+


Opposite Side Tagging• lepton (e,μ)from semileptonic decay of opposite b

• kaonfrom b→c→s decay of opposite b

• jetmomentum-weighted charge average of tracks in opposite side b jet

• taggers combined with Neural Network• performance independent of B species

calibrated in high statistics B+/B0 data

εD2(OST) : 1.8% (CDF), 2.2% (D∅)


B0 Mixing Fit Δmd

CDF: Δmd = 0.509 ± 0.010 (stat) ± 0.016 (syst) ps-1

D∅: Δmd = 0.506 ± 0.020 (stat) ± 0.016 (syst) ps-1

World average: Δmd = 0.507 ± 0.005 ps-1

P ∼e−t/τ

2τ(1 − SD · D · cos ∆md t)

B0 oscillation frequency

tagging calibration factor

decay time [cm]0.1 0.2 0.3 0.4

asym

met

ry

-0.2

-0.1

0.0

0.1

0.2Combined Opposite-Side Tagger

decay time [cm]0.1 0.2 0.3 0.4

asym

met

ry

-0.2

-0.1

0.0

0.1

0.2

data fit projection

contribution0dB contribution+

u B

CDF Run II Preliminary L=1fb-1


Same-Side Tagging (I)

• exploit b quark fragmentation‣ B0 / B+ likely accompanied by π+ / π-

‣ Bs likely accompanied by K+

➥ identify charge of leading track

• particle ID improves performance‣ separate kaons from pions‣ time-of-flight (TOF) & dE/dx

• dependent on B species‣ results in B0/B+ not applicable to Bs

• need to rely on Monte Carlo‣ data and MC thoroughly compared

+

b b

b b

b b

d

u s

u

s

d s

u d

B0

B0

B

!+

0"!

!0"

!

d

u s

d s

u

s

u d

}}

}}

}}

s

#

#


most powerful tagger available

• select quality tracks around B

• study algorithms based on ‣ PID, pLrel, pTrel, pT, ΔR

• decision: track charge of hightest NN tag candidate

• dilution: event-by-event, function of NN output

• power:εD2(SST) = 3.5%(had), 4.8% (sem)

+!s- -> DsB

log(LH(PID)) of tagging track-20 -10 0 10

dilu

tion

[%] (

agre

emen

t)

-100

10203040506070

CDF Run II Monte Carlo

π K

Neural Network output0 0.2 0.4 0.6 0.8 1

Dilu

tion

[%] (

agre

emen

t)

0

0.2

0.4

0.6

0.8

1CDF Run II Monte Carlo

)!"(s D# sB

Same-Side Tagging (II)

Fitting


Likelihood putting it all together

1

NLt =

SD D′

′

⊗R(t − t′;Sσt

σt) · E(t)κ

κ

κ

⊗F (κ)

L = Lmass · Lt · Lσt· LD

Δms1 ± cos( t )

2A

[for each sample component & event]

analytical computation

k-factor0.4 0.6 0.8 1.0

prob

abilit

y de

nsity

0.1

0.2

0.3

0.4 all

2 5.1 GeV/c! slD 4.9 < m

2 4.5 GeV/c! slD 4.3 < m

2 3.1 GeV/c! slD 2.9 < m

CDF Run II Monte Carlo s l D"B

k-factor0.4 0.6 0.8 1.0

Life

time

effic

ienc

y

0

0.5

1

1.5

21!1f1"

2!2f2"3!3f3"

4!4f4"

0.00179 0.00150 0.06806 0.01322 0.08388 0.02725 0.01218 0.68894 0.00757 0.00755 0.22568 0.00839

/ NDF = 105.02 / 107, Prob = 56.34%2#

Proper decay length [cm]0 0.1 0.2 0.3 0.4

$(d

ata

- fit)

/

-2

0

2

proper time [cm]proper time [cm]-0.2 -0.1 0.0 0.1 0.2

mµ

cand

idat

es /

20

10

210

310

410 data+! - D

fit+ f

++ f prompt

proper time [cm]-0.2 -0.1 0.0 0.1 0.2

CDF Run II Preliminary

+!s- -> DsB

log(LH(PID)) of tagging track-20 -10 0 10

dilu

tion

[%] (

agre

emen

t)

-100

10203040506070

CDF Run II Monte Carlo

e−

t

τ

τ


mµ

cand

idat

es p

er 3

0

1

10

210

310 data

fit+! (3)-

s D" s B

random bkg.+! (3)- D" 0 B-! (3)+

c# " b#


CDF Run II Preliminary -1 1 fb$L

]2) [GeV/c+!,-!)-K+(K"Mass(5.0 5.5 6.0

2Ca

ndid

ates

per

20

MeV

/c

0

200

400

600

data

fit+! -

s D# s B

satellites

combi bkg

! - D# 0 B! c$ # b$

]2) [GeV/c+!,-!)-K+(K"Mass(5.0 5.5 6.0

-1 1 fb%CDF Run II Preliminary L

Frequency Δms

Amplitude (A,σA) for fixed Δms

or


Fourier analysisTime domain

P(t) ~ 1± D cos Δmst

Frequency domain

P(t) ~ 1± A D cos Δmst

• fit amplitude A for different Δms probe values

‣ true Δms⇒ A=1, else A=0

• 95% CL exclusion condition A + 1.645 σA < 1

decay time, ps0.0 0.5 1.0 1.5 2.0

prob

abili

ty d

ensi

ty

0.00.1

0.20.30.4

0.50.6

0.70.8

time domain analysis

totalunmixedmixed

Oscillation Results


World Average Before Tevatron Run II

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

0 2.5 5 7.5 10 12.5 15 17.5 20 22.5 25

!ms (ps-1)

Ampli

tude

data ± 1 " 95% CL limit 14.4 ps-1

1.645 " sensitivity 18.2 ps-1

data ± 1.645 "data ± 1.645 " (stat only)

Average for PDG 2006

Sensitivity: 18.2 ps-1

Δms>14.4 ps-1 @95%CL


D∅ Result

]-1 [pssm!0 5 10 15 20 25

Ampl

itude

-4

-2

0

2

4 (stat.)" 1.645 ±data syst.)# (stat. " 1.645 ±data

" 1 ±data

-195% CL limit: 14.8ps -1Expected limit: 14.1ps

DØ Run II

-11 fb


Δms ε [17,21] ps-1 @90%CL


Semileptonic Scan

]-1 [pssm!0 10 20 30

Ampl

itude

-4

-2

0

2

4 " 1 ± data " 1.645

" 1.645 ± data (stat. only)" 1.645 ± data

95% CL limitsensitivity

-116.5 ps-119.4 ps

-1 1 fb#L CDF Run II Preliminary

X+ l-s D$ 0

sB



Hadronic Scan

]-1 [pssm!0 5 10 15 20 25 30 35

Ampl

itude

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2" 1 ± data

" 1.645

" 1.645 ± data (stat. only)" 1.645 ± data

95% CL limitsensitivity

-117.1 ps-130.7 ps

CDF Run II Preliminary -1L = 1.0 fb



]-1 [pssm!0 5 10 15 20 25 30 35

Amplitude

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

0.20±=17.75)=1.21 sm! A(

A/σA=6.05

Sensitivity 31.3 ps-1

Combined Amplitude Scan

CDF Run II


Likelihood Profile

]-1 [pssm!0 5 10 15 20 25 30 35

likel

ihoo

d ra

tio

-20-15-10-505

1015202530

combined

semileptonic

hadronic


L = -17.26!min

How often can random tags produce a minimum at least as deep?

-ln[L

(A=

1)/L

(A=

0)]


28 trials out of 350 millionp-value = 8x10-8 corresponding to 5.4σ

➠passed observation criteria

Likelihood Significance

min log(L)!-20 -15 -10 -5 00

2

4

6

8

10

12

14610×

observed

min log(L)!-20 -15 -10 -5 0

p-va

lue

-910

-810

-710

-610

-510

-410

-310

-210

-1101

"5



Δms Measurement

Δms = 17.77 ± 0.10(stat) ± 0.07(syst) ps-1

]-1 [pssm!15 16 17 18 19 20

log(

L)!

-10

0

10

20

30combinedhadronicsemileptonic


[ps]sm!/"Decay Time Modulo 20 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Fitte

d Am

plitu

de

-2

-1

0

1

2

datacosine with A=1.28

CDF Run II Preliminary -1L = 1.0 fbVisualizing the Result

Impact on CKMmatrix elements determination


Determination of |Vtd/Vts|

∆ms

∆md

=mBs

mB0

ξ2|Vts|2

|Vtd|2

∆md = 0.505 ± 0.005 ps−1

ξ2= 1.21

+0.047−0.035

[M.Okamoto, hep-lat/0510113]

[PRL 96, 202001 (2006)]

[PDG 2006]

other inputs:

compare to Belle b→dϒ:

[ PRL 96, 221601 (2006)]

|Vtd/Vts| = 0.199+0.026−0.025(exp)+0.018

−0.015(th)

➠

∣∣∣∣

Vtd

Vts

∣∣∣∣ = 0.2060 ± 0.0007(exp) ±0.0081

0.0060 (th)

no longer limited by experimental measurements

mB0/mBs= 0.98390

0

0.2

0.4

0.6

0.8

1

1.2

0.16 0.18 0.2 0.22 0.24 0.26 0.28 0.3

!"m(d,s),SU(3) = 1.21 +0.047 – 0.035 (hep-lat/0510113)

BRs WA - !V#,SU(3) = 1.17 ± 0.09 (hep-ph/0603232)

CKM fit w/o "msCDF measurementBR(B0 $ %0#) / BR(B0 $ K*0#)

|Vtd/Vts|

1 –

CL

WA

CK Mf i t t e r

BEAUTY 06


CKM Fit, without CDF measurement

!-1 -0.5 0 0.5 1

"-1

-0.5

0

0.5

1#

$

%

dm&

K'

cbVubV

!-1 -0.5 0 0.5 1

"-1

-0.5

0

0.5

1

UT Fit, without Δms constraint

beforeafter

!-1 -0.5 0 0.5 1

"-1

-0.5

0

0.5

1#

$

%

sm&dm& dm&

K'

cbVubV

!-1 -0.5 0 0.5 1

"-1

-0.5

0

0.5

1

UT Fit, with CDF measurement

-1.5

-1

-0.5

0

0.5

1

1.5

-1 -0.5 0 0.5 1 1.5 2

sin 2!

sol. w/ cos 2! < 0(excl. at CL > 0.95)

excluded at CL > 0.95

"

"

#

#

$md

$ms & $md% = 1.21 +0.047

– 0.035 (hep-lat/0510113)

&K

&K

|Vub/Vcb|

sin 2!

sol. w/ cos 2! < 0(excl. at CL > 0.95)

excluded at CL > 0.95

#

!"

'

(

excluded area has CL > 0.95

C K Mf i t t e r

EPS05+CDF

CKM Fit, with CDF measurement

Impact on Unitarity Triangle Fit


Measurement vs Expectation

0

0.2

0.4

0.6

0.8

1

1.2

14 16 18 20 22 24 26 28 30 32

CKM fit w/o !msCDF measurement

!ms (ps-1)

1 –

CL

CK Mf i t t e r

BEAUTY 06

]-1[pssm!10 20 30 40

Prob

abili

ty d

ensi

ty0

0.0005

0.001

0.0015

]-1[pssm!10 20 30 40

Prob

abili

ty d

ensi

ty0

0.0005

0.001

0.0015

]-1[pssm!10 20 30 40

Prob

abili

ty d

ensi

ty0

0.0005

0.001

0.0015

CDF Δms Measurement

Combined measurement of mixing frequency and mixing phase provides model independent limits on New Physics


ConclusionLong journey ended

Observation of Bs-Bs oscillations‣ probability of random tag fluctuation ~ 8.10-8: >5σ‣ most precise measurement of oscillation frequency

Δms = 17.77 ± 0.10(stat) ± 0.07(syst) ps-1

]-1 [pssm!0 5 10 15 20 25 30 35

Amplitude

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

0.20±=17.75)=1.21 sm! A( PRL 97, 242003 2006

-

Observation of Bs mixing - Fermilableonardo/docs/seminar_cern.pdf · 2015-11-17 · N. Leonardo,...

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Transcript of Observation of Bs mixing - Fermilableonardo/docs/seminar_cern.pdf · 2015-11-17 · N. Leonardo,...