Measurements of the Bs Mixing Phase at CDF
Robert Harr Wayne State University
26 July 2011 R. Harr, Bs Phase at CDF 1
Outline • Status of the CP violaGon in Bs J/ψ φ analysis • Bs J/ψ f0(980) branching fracGon and lifeGme • Measurement of χb • CP violaGon in Bs φ φ • Summary
26 July 2011 R. Harr, Bs Phase at CDF 2
The CDF Detector
26 July 2011 R. Harr, Bs Phase at CDF 3
muons 0.6 < |η| < 1.0
muons |η| < 0.6
vertex detector
central tracker
1.4T solenoid
BS à J/ψ φ
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CP ViolaGon in Bs J/ψ φ Decays
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SM predicts Gny CP violaGon in Bs mixing.
New physics can have a detectable effect.
Current Status
26 July 2011 R. Harr, Bs Phase at CDF 6
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-1CDF Run II Preliminary L = 5.2 fb95% CL68% CLSM prediction
CDF and D0 originally had ~2σ inconsistencies with SM predicGon, were more consistent with each other..
CDF 5.2 \-‐1 result (summer 2010) is more consistent with SM, difference is ~1σ
An update with (7+) \-‐1
data set is in progress.
BS à J/ψ f0(980)
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Interest in Bs J/ψ f0(980) • This is a P V S decay. • The decay is S-‐wave – may effect the Bs J/ψ φ analysis when f0 K+K-‐.
• Measure the B.F. to help constrain effects in J/ψ φ. • AddiGonally, this final state is CP odd, and neglecGng direct CP violaGon, comes only from BH eigenstate. – LifeGme gives τH. – Can be used to measure CP violaGon without angular analysis.
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CDF ObservaGon of Bs J/ψ f0(980)
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Flade distribuGon
Rf0/φ = 0.257± 0.020(stat)± 0.014(syst)B(B0
s → J/ψf0(980))B(f0(980)→ π+π−) =(1.63± 0.12(stat)± 0.09(syst)± 0.50(pdg))× 10−4
LifeGme in Bs J/ψ f0(980)
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In the absence of CP violaGon, measures the lifeGme of BH state. Simultaneous fit to mass, decay Gme, and decay Gme error.
First LifeGme Measurement
• Interpret as first direct measurement of τH
• Compares well to indirect measurements of τH, and theoreGcal predicGons.
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τ(B0s → J/ψf0(980)) = 1.70+0.12
−0.11(stat)± 0.03(syst) ps
MEASUREMENT OF χB
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χ • χ is the average mixing probability
• And is related to R:
• Difference in average χ from LEP (0.1259±0.0042) and Tevatron (0.147±0.011)
R =N
++ +N−−
NOS
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CDF Run I: PRD 69, 012002 (2004)
χb =Γ(B0→ B̄0→ �+X)
Γ(B→ �±X)= fdχd + fsχs
RelaGon of R to χ • R has contribuGons from mixing, and other decay processes such as – b c µ decays – b ψX, b χcX, and other b cc q decays
• We account for these effects with a parameter f, determined from simulaGon to be f=0.176±0.011
• We obtain the relaGon:
R =f�χ2 +(1−χ)2
�+2χ(1−χ)(1− f )
(1− f )�χ2 +(1−χ)2
�+2χ(1−χ) f
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χ Measurement • Use dimuon triggered data from 1.44/\ of int. lumi. • Same selecGon requirements as described for ASL measurement.
• Require that both muons have a hit in one of the two innermost silicon layers – Removes a large fracGon of poorly understood events – Reduces overall staGsGcs.
• Fit the OS, ++, and – impact parameter distribuGons simultaneously
• Determine R from bb component of the fit.
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_
Fit Results
OS
++
-‐-‐
1D projecGons of 2D fits
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Fit probability 78.5%
χ Result • R=0.467±0.008 (stat only) • Varying the templates within their uncertainGes yields a systemaGc error of 0.007
• R = 0.467±0.011 (stat and syst) • Yields χ = 0.126 ± 0.008 (0.005 is due to R and 0.006 to f)
• Compare to LEP average χ = 0.1259 ± 0.0042
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BS à φ φ
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Angular Variables • This is a P V V decay – We use the helicity frame with variables φ, θ1, θ2
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Fit Data from 2.9 \-‐1 of Lumi.
• Combined fit to mass and angular variable dists.
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DataFit
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DataFit
""#sBBackground
|A0|2 = 0.348±0.041 (stat) ± 0.021 (syst) |A|||2 = 0.287±0.043 (stat) ± 0.011 (syst) |Aperp|2 = 0.365±0.044 (stat) ± 0.027 (syst) cosδ|| = -‐0.91+0.15-‐0.13 (stat) ± 0.009 (syst)
fL = 0.348±0.041 (stat) ± 0.021 (syst) fT = 0.652±0.041 (stat) ± 0.021 (syst)
arXiv: 1107.4999
Triple Product Asymmetries
• TP asym. is T odd violates CP under CPT cons. • NP enters in interfer. betwn CP even and odd amplitudes • Result is consistent with zero (SM expectaGon)
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u = sinφ cos φ
v = sinφ×sign (cos θ1 cos θ2)
Au = -‐0.007 ± 0.064 (stat) ± 0.018 (syst) Av = -‐0.120 ± 0.064 (stat) ± 0.016 (syst)
New arXiv: 1107.4999
First measurement
Dada and London, Int. J. Mod. Phys. A 19, 2505 (2004)
Summary • The new χ result is in agreement with the LEP measurements, possibly sedling a long standing difference.
• First measurement of triple products in Bs φφ decays, consistent with SM expectaGon of zero.
• First measurement of lifeGme in Bs decay to CP odd eigenstate Bs J/ψ f0
• Update in progress for Bs J/ψ φ analysis
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_
BACKUP
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The Fit FuncGon (for completeness)
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2 3 DETAILS
ASL =N++ −N−−
N++ + N−−
L =�
i
�
j
��n(i,j)
ij
e−�ij
n(i, j)!
�
�ij =BBXS · SXS
b(i) · SXS
b(j) + BBXS
FK· Sb(i) · Sb(j)
+�CC + CCXS
FK
�· Sc(i) · Sc(j) + PP XS · Sp(i) · Sp(j)
+1
2
�BP XS · (Sb(i) · Sp(j) + Sp(i) · Sb(j))
+ CP XS · (Sc(i) · Sp(j) + Sp(i) · Sc(j))
+ BCXS · (Sb(i) · Sc(j) + Sc(i) · Sb(j))�
1
2
�(CP − BP )2
CP + BP + (0.14 · BP )2+
(BC − 0.046 · BB)2
BC + (0.046)2 · BB + (0.013 · BB)2
�
CP LS = (1.05 ± 0.05) · CP OS CP ++ = (1.2 ± 0.1) · CP −−
BP LS = (0.87 ± 0.07) · BP OS BP ++ = (1.15 ± 0.05) · BP −−
BCLS = BCOS BC++ = BC−−
2 General
Here we have the general Text
3 Details
And here are the details
3.1 A nice graph
Fig. 1 shows a nice graph.
3.2 URLs
This is a link to the CDF home page. And this is a link to Spires:
And this one goes to a CDF note:
CDF Note 5981.
Fit Results
26 July 2011 R. Harr, Bs Phase at CDF 25
|A0|2 = 0.348±0.041 (stat) ± 0.021 (syst) |A|||2 = 0.287±0.043 (stat) ± 0.011 (syst) |Aperp|2 = 0.365±0.044 (stat) ± 0.027 (syst) cosδ|| = -‐0.91+0.15-‐0.13 (stat) ± 0.009 (syst)
fL = 0.348±0.041 (stat) ± 0.021 (syst) fT = 0.652±0.041 (stat) ± 0.021 (syst)
0f0 0.2 0.4 0.6 0.8 1
f0.2
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CDFII CL=68.3%Beneke et al., NPB 774 (2007)Datta et al., EPJC 60 (2009)Cheng et al., PRD 80 (2009)Ali et al., PRD 65 (2002)
)/20
=(1 - ff
-1CDF Run II Preliminary L = 2.9 fb
CDF Public Note 10064