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Measurement of CP Violation in B s J / at CDF Michal Kreps for the CDF collaboration Physics Department -1 -1 CDF Run II Preliminary L = 1.35 fb CDF Run II Preliminary L = 2.8 fb ) ) SM prediction 0.6 0.6 95% C.L.

slide-1
SLIDE 1

Measurement of CP Violation in Bs → J/ ψφ at CDF

Michal Kreps for the CDF collaboration

(rad)

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CDF Run II Preliminary L = 1.35 fb 95% C.L. 68% C.L. SM prediction

⇒

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CDF Run II Preliminary L = 2.8 fb 95% C.L. 68% C.L. SM prediction New Physics

⇒ ?

www2.warwick.ac.uk

Physics Department

slide-2
SLIDE 2

Discovery of CP violation

Neutral kaon puzzle in late 1950s Two particles (K1, K2) with same mass, but different lifetime and different decay mode K2 is CP odd and if CP is conserved can decay only to 3 π Observation of K2 → π+π− in 1964 by Cronin and Fitch ⇔ CP is not conserved

2 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-3
SLIDE 3

Explaining CP violation

Observation by Cronin and Fitch requires ≈ 10−3 admixture of wrong CP state in wave function In 1973 Kobayashi and Maskawa concludes that No reasonable way to include CP violation in model with 4 quarks Introduction of CP violation needs new particles One of the suggested ways uses 6 quark model CP violation ⇔ complex phase in quark mixing (CKM) matrix    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    Nobel prize in 2008

3 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-4
SLIDE 4

Implications

When Kobayashi and Maskawa proposed their explanations, only 3 quarks were known The six quark model had several implications: Existence of another 3 quarks to be seen by experiment In 1980/1981 several people predicted large CP violation in B system

  • 1

1

  • 1

1

  • 1

1 sin2φ1 . sin(∆md∆t) (c) J/ψKL (ξf = +1) (a) Combined Asymmetry (b) (cc)KS (ξf = −1)

−
  • 8
  • 4

8 4 ∆t (ps)

  • 1

1 (d) Non-CP sample

  • 1
  • 0.5

0.5 1

BABAR

  • 1
  • 0.5

0.5 1

  • 5

5

Asymmetry ∆t (ps)

  • 4
  • 3
  • 2
  • 1
  • 1

1 2

sin2β ln(L/Lmax)

Start of dedicated B physics experiments In 2001 Belle and Babar experiments observe large CP violation in B0 decay Since then many measure- ments performed to check idea

4 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-5
SLIDE 5

Global status

VCKM =    1 − λ2/2

λ

Aλ3(ρ − iη)

−λ

1 − λ2/2 Aλ2 Aλ3(1 − ρ − iη)

−Aλ2

1   

γ γ α α

d

m ∆

K

ε

K

ε

s

m ∆ &

d

m ∆

SL ub

V

ν τ ub

V β sin 2

(excl. at CL > 0.95) < 0 β

  • sol. w/ cos 2
e x c l u d e d a t C L > . 9 5

α β γ

ρ

  • 1.0
  • 0.5

0.0 0.5 1.0 1.5 2.0

η

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5

excluded area has CL > 0.95 ICHEP 10

CKM

f i t t e r

5 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-6
SLIDE 6

Are we done?

Does not look to be case Many unanswered questions SM has many free parameters What is the meaning of generation, why we need more than

  • ne?

What is the origin of dark matter and dark energy? How current matter-antimatter asymmetry is generated? No baryon number violation in SM CP violation in SM is many order of magnitude too small In SM cannot generate needed phase transition SM is probably just low energy approximation of final big theory of everything

6 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-7
SLIDE 7

Role of flavor physics

Several extensions of SM exists, each postulating new particles Some examples Fourth generation introduces two additional quark, VCKM is changed to 4 × 4 matrix Supersymmetry has partner for each SM particle In supersymmetry squarks/sleptons mix through 3 × 3 matrix    m2

11

m2

12

m2

13

m2

21

m2

22

m2

23

m2

31

m2

32

m2

33

   Looking for indirect effects of new physics to discover it If new physics is discovered, understand which model is right one

7 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-8
SLIDE 8

CPV in Bs → J/

ψφ

   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    Vts known from unitarity Need to check also by experiment Best testing ground is decay Bs → J/

ψφ

b t, c, u ¯ t, ¯ c, ¯ u W − W + ¯ b s ¯ s s ¯ c c

¯ b s ¯ c c ¯ s s

New physics in mixing can have large effect on CP violation Search for large CP violation in Bs → J/

ψφ

8 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-9
SLIDE 9

Sidenote on phases

Bs system is described by equation i d dt

  • B0

s(t)

  • ¯

B0

s(t)

  • =
  • M − i

2Γ B0

s(t)

  • ¯

B0

s(t)

  • Box diagram of mixing give rise to M12 and Γ12

Interesting quantities and relation to observables:

∆Ms = 2|MSM

12,s| · |∆s|

φs = arg(−M12/Γ12) = φSM

s

+ φ∆

s , in SM φs = (4.2 ± 1.4) · 10−3

∆Γs = 2|Γ12,s| · cos

  • φSM

s

+ φ∆

s

  • CP Violation in Bs → J/

ψφ measures φJ/Ψφ

s

= −2βs + φ∆

s + δSM

  • Peng. + δNP

Peng.

in SM 2βs = 2 arg(−VtsV ∗

tb/VcsV ∗ cb) ≈ 0.04

With current CDF precision we really test presence of large φ∆

s

9 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-10
SLIDE 10

Analysis logic

Principle is to measure time dependent asymmetry of CP eigenstate A = N(B, t) − N(B, t) N(B, t) + N(B, t) We need to find in data Bs → J/

ψφ decays

Measure decay time Find out whether it was produced as B or B

K+ K− Bs

+

µ

−

µ K Bq K l

10 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-11
SLIDE 11

Likelihood anatomy

Signal PDF for single tag Ps(t,

ρ, ξ|D, σt)

= 1 + ξD 2 P(t,

ρ|σt)ǫ( ρ)

+1 − ξD 2 ¯ P(t,

ρ|σt)ǫ( ρ) ξ = −1, 0, 1 is tagging decision D is event-specific dilution ǫ( ρ) - acceptance function in angular space

P(t,

ρ|σt) ( ¯

P(t,

ρ|σt)) is PDF for Bs (Bs)

11 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-12
SLIDE 12

Likelihood anatomy

d4P(t,

ρ)

dtd

ρ ∝ |A0|2T+f1( ρ) + |A|2T+f2( ρ) + |A⊥|2T−f3( ρ)

+

|A||A⊥|U±f4( ρ) + |A0||A| cos(δ)T+f5( ρ)

+

|A0||A⊥|V±f6( ρ) T± = e−Γt ×

[cosh(∆Γt/2) ∓ cos(2βs) sinh(∆Γt/2)

∓ η sin(2βs) sin(∆mst)] , U± = ±e−Γt ×

  • sin(δ⊥ − δ) cos(∆mst)

−

cos(δ⊥ − δ) cos(2βs) sin(∆mst)

±

cos(δ⊥ − δ) sin(2βs) sinh(∆Γt/2)

  • ,

V± = ±e−Γt ×

[sin(δ⊥) cos(∆mst)

−

cos(δ⊥) cos(2βs) sin(∆mst)

±

cos(δ⊥) sin(2βs) sinh(∆Γt/2)] .

12 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-13
SLIDE 13

Issue of s-wave

We reconstruct Bs → J/

ψφ with φ → K +K −

But wide resonance f0(980) can also decay to K +K − and Bs → J/

ψK +K − is also possible (called s-wave)

There are arguments that s-wave can be large Stone et al, PRD79, 07024 (2009) predicts B(Bs → J/

ψf0(980))B(f0(980) → ππ)

B(Bs → J/

ψφ)B(φ → KK) ≃ 0.2 − 0.3

Best upper bound from Belle B(Bs → J/

ψf0(980))B(f0(980) → ππ) < 1.63 · 10−4 at 90% C.L.

S-wave can contribute to reconstructed signal It is CP-odd eigenstate with its own angular and time dependence Sizeable contribution which is not accounted for can bias result

⇒ Account for it in the likelihood

13 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

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SLIDE 14

Treatment of s-wave

Add amplitude for s-wave ⇔ four angular terms (amplitude2 + 3 interference terms) S-wave amplitude is pure CP-odd eigenstate with its own angular dependence Strong phases vary over resonance

⇒ Need to start with K +K − mass included

Relativistic Breit-Wigner propagator for p-wave Constant for s-wave Keep K +K − mass as unobserved ⇔ integrate over it Interference between p-wave and s-wave could break last symmetry Full math spelled out in arXiv:1008.4283

14 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-15
SLIDE 15

Previous results

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CDF Run II Preliminary L = 1.35 fb 95% C.L. 68% C.L. SM prediction

(rad)

s

β

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(ps Γ ∆

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0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 2.8 fb 95% C.L. 68% C.L. SM prediction New Physics

CDF 1.35 fb−1 p-value = 15% CDF 2.8 fb−1 p-value = 7% CDF 2.8 fb−1 + DØ 2.8 fb−1 p-value = 3.4% What next?

15 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-16
SLIDE 16

Tevatron and CDF experiment

250 500 750 1000 1250 1500 1750 2000 50 100 150 200 250 300 350 Day CDF Acquired Luminosity (pb-1)

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

pp collisions at √s = 1.96 TeV Peak luminosity ≈ 3.5 − 3.8 · 1032 cm−2s−1 Collected about ≈ 7fb−1

16 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-17
SLIDE 17

Selection

Network output

  • 1.0
  • 0.5

0.0 0.5 1.0

Candidates per 0.02

3

10

4

10

5

10 Signal Background

CDF Run II Preliminary

  • 1

L=5.2 fb

]

2

) [GeV/c φ ψ Mass(J/

5.28 5.3 5.32 5.34 5.36 5.38 5.4 5.42 5.44 5.46

2

Candidates per 2 MeV/c

100 200 300 400 500 600 700 800 900

  • 1

CDF Run II preliminary L = 5.2 fb

Neural Network Cut

  • 0.5

0.0 0.5 1.0 parabolic error

s

β 0.110 0.115 0.120 0.125 0.130 0.135 0.140

CDF Simulation = 0.02

s

β Input

Latest analysis uses 5.2 fb−1 Events selected using dimuon trigger Typical event has few dozens tracks ⇒ lot of background Neural network to select interesting events Select ≈ 6500 Bs → J/

ψφ decays

17 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-18
SLIDE 18

Flavor tagging

K−

Bs

SST OST

a l− b K+

b u u B b

s

Κ s s/d

/d

/π

+ +

/d

Determination of the flavor at production time Difficult task due to large number of tracks Benefits from PID Calibrated with data

18 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-19
SLIDE 19

OST Calibration

]

2

invariant mass [GeV/c

+

K ψ J/ 5.20 5.25 5.30 5.35 5.40 )

2

entries/(5 MeV/c

2000 4000 6000 8000 10000 12000 14000

  • 1

CDF II Preliminary, 5.2 fb

51,920 +/- 388 Signal Events

OST Predicted Dilution 0.0 0.2 0.4 0.6 0.8 1.0 OST Measured Dilution

  • 1.0
  • 0.5

0.0 0.5 1.0 1.5 2.0

  • 1

CDF Run II Preliminary L = 5.2 fb events

+

B 0.09 ± Slope = 0.93

OST Predicted Dilution 0.0 0.2 0.4 0.6 0.8 1.0 OST Measured Dilution

  • 1.0
  • 0.5

0.0 0.5 1.0 1.5 2.0

  • 1

CDF Run II Preliminary L = 5.2 fb events

  • B

0.10 ± Slope = 1.12

B+ B− Flavor tagging algorithm is characterized by Efficiency ǫ Dilution D = 2 · P − 1 Quantity ǫD2 defines effective statistics Opposite side tagging is independent of studied hadron Effective power of OST is ǫD2 = 1.2%

19 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-20
SLIDE 20

SSKT Calibration

5.4 5.5 5.6

2

Candidates per 3 MeV/c

50 100 150 200 250 300 350 400

Data Fit Function π

s

D →

s

B K

s

D →

s

B

  • Comb. Backgr.

X

s

D → B

75 ± S = 5613 33 ± B = 1070 0.17 ± S/B = 5.25 0.70 ± = 68.66 S+B S/
  • 1

CDF Run 2 Preliminary, L = 5.2 fb (+ cc)

  • K
+

K → φ ,

  • π

φ →

  • s

, D

+

π

  • s

D →

s

B 2

Invariant Mass in GeV/c

5.4 5.5 5.6

data (data - fit)

  • 2

2

  • 1

Mixing Frequency in ps

10 20 30

Amplitude

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5 2.0

Amplitude A

  • 1

Sensitivity: 37.0 ps

  • 1

CDF Run 2 Preliminary, L = 5.2 fb

  • 1

Mixing Frequency in ps

10 20 30

Amplitude

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5 2.0

SSKT depends on the meson we study Only way to calibrate is to use Bs itself Fortunately Bs oscillation is sensitive to quality of tagging Principle A = Nmix−Nunmix

Nmix+Nunmix = A · D cos (∆mt)

Use decays: Bs → Dsπ with Ds → φπ, Ds → K ∗K and Ds → πππ Bs → Dsπππ with Ds → φπ In total ≈ 12900 signal events Total tagging power ǫD2 = 3.2 ± 1.4%

∆ms = 17.79 ± 0.07(stat)

20 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-21
SLIDE 21

Angular efficiencies

CDF Run II Preliminary, L=5.2 fb−1

Derived from large statistics MC Parameterized in three dimensions CP Violation relatively insensitive to exact details Efficiency compares well with angular distributions of combinato- rial background

21 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-22
SLIDE 22

Lifetime and width difference

KK) [cm] ψ ct (J/

  • 0.2
  • 0.1

0.1 0.2 0.3

m µ events per 50

1 10

2

10

3

10

Data - signal region Fit Signal Light Heavy Background

  • 4
  • 2

2 4

pull

  • 1

CDF Run II Preliminary L = 5.2 fb

Distribution for BsH Distribution for BsL Signal mass region Under SM assumption (βs = 0) we measure: cτ =

2 ΓH+ΓL = 1.529 ± 0.025(stat) ± 0.012(syst) ps

∆Γs = 0.075 ± 0.035(stat) ± 0.01(syst) ps−1

22 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-23
SLIDE 23

Polarization amplitudes

) ψ cos(

  • 1.0
  • 0.5

0.0 0.5 Entries per 0.12 rad 100 200 300 400 500 600 700

Data Fit

) θ cos(

  • 1.0
  • 0.5

0.0 0.5 Entries per 0.12 rad 100 200 300 400 500 600 700

Data Fit

φ 2 4 6 Entries per 0.42 rad 100 200 300 400 500 600 700

Data Fit

CDF Run II Preliminary, L = 5.2 fb

) ψ cos(

  • 1.0
  • 0.5

0.0 0.5 Entries per 0.12 rad 100 200 300 400 500 600 700 800

Data Fit

) θ cos(

  • 1.0
  • 0.5

0.0 0.5 Entries per 0.12 rad 100 200 300 400 500 600 700 800

Data Fit

φ 2 4 6 Entries per 0.42 rad 100 200 300 400 500 600 700 800

Data Fit

CDF Run II Preliminary, L = 5.2 fb

|A|||2 = 0.231 ± 0.014(stat) ± 0.015(syst) |A0|2 = 0.524 ± 0.013(stat) ± 0.015(syst) φ⊥ = 2.95 ± 0.64(stat) ± 0.07(syst)

Signal Background

23 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-24
SLIDE 24

CP Violation

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb

95% CL 68% CL SM prediction

(rad)

s

β

  • 1

1 log (L) ∆ 2 2 4 6 8 10 12 14 16 18

95% CL 68% CL SM prediction

  • 1

CDF Run II Preliminary L = 5.2 fb

SM p-value is 44% Corresponds to 0.8σ Significant improvement Strong phases free SM p-value is 31% Comparable to 2D case ⇔ ∆Γ consistent with SM

βs ∈ [0.02, 0.52] ∪ [1.08, 1.55]

@ 68% C.L.

24 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-25
SLIDE 25

Comparison to previous result

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

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CDF Run II Preliminary L = 5.2 fb

95% CL 68% CL SM prediction

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 2.8 fb 95% C.L. 68% C.L. SM prediction New Physics

Concentrate on size of the allowed region Significant improvement compared to our previous result

25 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-26
SLIDE 26

Size of the adjustment

)

p

ln(L ∆ 2 5 10 15 1-CL

  • 2

10

  • 1

10 1

68% CL 95% CL

  • 1

CDF Run II Preliminary L = 5.2 fb

randomized nuisance parameters non-Gaussian errors ideal

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb

95% CL 68% CL SM prediction

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb

5.99 2.30 SM prediction

26 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-27
SLIDE 27

S-wave check

Prob 0.3225

)

2

Mass (GeV/c

  • K

+

K ψ J/ 5.30 5.35 5.40 5.45

2

Candidates per 4 MeV/c 500 1000 1500 2000 2500 3000 3500 4000 4500

Prob 0.3225
  • 1

CDF Run II Preliminary L = 3.8 fb

data total fit signal

s

B combinatorial bkg misreconstructed B

)

2

Mass (GeV/c

  • K

+

K 1.00 1.05 500 1000 1500 2000 2500

data total fit combinatorial background misreconstructed B f

  • 1

CDF Run II Preliminary 3.8 fb

2

Candidates per 2 MeV/c S-wave fraction 0.00 0.02 0.04 0.06 0.08 0.10 log (L) ∆ 2 1 2 3 4 5 6 7 8 9

  • 1

CDF Run II Preliminary L = 5.2 fb

95% CL 68% CL

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

S-wave not included S-wave included

5.99 2.30

  • 1

CDF Run II Preliminary L = 5.2 fb

Q: Is change since last time due to previously omitted s-wave? A: No, likelihood almost same with s-wave fixed to zero Q: Is the K +K − mass consistent with our fit model? A: Yes it is

27 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-28
SLIDE 28

Effect of flavor tagging

With tagging of ǫD2 ≈ 5% we don’t gain lot in precision Main effect in reducing ambiguities Untagged case symmetric under each 2βs → −2βs

δ⊥ → δ⊥ + π ∆Γ → −∆Γ

2βs → 2βs − π Tagged symmetry 2βs → π − 2βs

∆Γ → −∆Γ δ|| → 2π − δ|| δ⊥ → π − δ⊥

28 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-29
SLIDE 29

Different parts of data

29 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-30
SLIDE 30

Different parts of data

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb S-wave not included

  • 1

Data 0-1.35 fb

5.99 2.30 SM prediction

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb S-wave not included

  • 1

Data 1.35-2.8 fb

5.99 2.30 SM prediction

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

S-wave not included

  • 1

Data 2.8-5.2 fb

5.99 2.30 SM prediction

29 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-31
SLIDE 31

Conclusions

Significantly improved measurement of the CPV in Bs → J/

ψφ βs ∈ [0.02, 0.52] ∪ [1.08, 1.55] @ 68% C.L.

CDF data now agree on the ≈ 1σ level with SM Best measurement of Mean lifetime Width difference between mass eigenstates Polarization amplitudes

(rad)

s

β

  • 1

1 )

  • 1

(ps Γ ∆

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

  • 1

CDF Run II Preliminary L = 5.2 fb

95% CL 68% CL SM prediction

30 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010

slide-32
SLIDE 32

Prospects

Couple of improvements possible beyond collecting data Include other triggers gives ≈ 25% more statistics Add Bs → ψ(2S)φ Look for Bs → J/

ψf0(980) with f0(980) → π+π−

Add K +K− mass as fit variable - helps in ambiguity resolution Still collecting data, expect to have ≈ 2 times more by the end of 2011 Extension of running by 3 years under discussion

store number

1000 2000 3000 4000 5000 6000 7000 8000 2000 4000 6000 8000

01/10 01/09 01/08 01/07 01/06 01/05 01/04 01/03

Delivered Acquired

)

  • 1

Luminosity (pb

250 500 750 1000 1250 1500 1750 2000 50 100 150 200 250 300 350 Day CDF Acquired Luminosity (pb-1)

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

31 Michal Kreps – Measurement of CP Violation in Bs→J

/ ψφ at CDF

17 November 2010