heavy flavour physics at the tevatron farrukh azfar, oxford university (cdf) zero to z0 conference:...
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Heavy Flavour Physics at the Tevatron
Farrukh Azfar, Oxford University (CDF)
Zero to Z0 Conference: Fermilab, May 12-14 2004
Overview of this presentation:
Preliminary:
1) Tevatron performance, Beauty physics at hadron colliders
2) CDF and D0 detectors, relevance for B-physics Physics Results & Prospects:
3) Tests of Heavy Quark Expansion (HQE) Masses and Lifetimes of B hadrons. Hadronic Moments.
4) Search for Flavour Changing Neutral Current (FCNC), Rare decays…
5) Mixing and CP violation (CPV), Toward Bs-mixing & CKM angle
6) Conclusion and Summary
Tevatron pp collider upgrade & performance, integrated luminosity
Performance Improvement:
-Collision rate: 3.5 s 396 ns
- Bunches: 6x6 36x36
-Center of Mass energy: 1.81.96 TeV/c2
-Peak luminosity : 2.4x10317.2 x1031cm2s-1
(Below target by x2.5, but improving)
Run-IIa -Goals are Ldt=2fb-1 (x20 Run-I, 1992-96)
Run-II Tevatron Upgrades: -Main Injector for Tevatron -Higher proton intensity -Anti-proton transfer efficiency increased -Anti-proton recycler (coming after autumn)
CDF
Data taking efficiency~80-90% for CDF & D0 Results in this talk:CDF analyses ~65-250 pb-1 D analyses ~115-250 pb-1
290 pb-1 on tape at CDF & D0
Why Beauty at the Hadron-Hadron Colliders ?(bb) at (4S) = 1nb (B-factories) (Compare bb
production (bb) at Z0 = 7nb (LEP) cross section)(bb) at pp (1.96TeV/c2)=150b (Tevatron Experiments)
More B @ Tevatron but inelastic is 103 x (bb) -Select b-data online, key: right detector & triggers -Rewards: all B-hadrons e.g. B, B0, Bs, Bc
, b … (unlike B-factories) & higher than at Z0
Clever Online B Selection (Triggers):
”Traditional” Use leptons from e.g. BsDs+- CDF & D0
(single-lepton) & B J/K*, J/+:CDF & D0 (di-lepton) ”Modern” long B lifetimes large impact parameter (IP) of daughter tracks : CDF (D0 in progress)SVT trigger: purely hadronic decays of B and Charme.g. D0+- , BsDs
+-, Ds+ K+K- (1st @ hadron machine!)
CDF Apply High IP requirement in single-Lepton data as well
The CDF & D0 Detectors in Run-IICDF Detector
D0 Detector
CDF & D0 Detectors are bothMulti-purpose with:-Axial Solenoid-Inner Silicon micovertex detectors-Outer trackers -Calorimetry -Muon ID-Muon Triggering (CDF & D0)-High IP Track triggering (CDF)
D0: Better calorimetry, better muon & tracking coverageCDF: Better momentum measurement, also can select high IP tracks, some Hadron ID with dE/dX, TOF
Physics Results, Testing HQE: B-hadron lifetimes, massesGoals, Techniques
Fully Reconstructed B from J/di-muon trigger (e.g. Bs J/) or High IP trigger (e.g. BsK+K-)-Find vertex, 2-d distance: Lxy invariant mass: MB momentum in 2-d: Pt
B Find proper time: c= Lxy. MB/PtB
- Fit mass distribution only or mass and lifetime distributions
-Decays selected usingSVT trigger have biased c-”Turn-on” near low IP cut-”Turn-off” at high IP cut-Bias fix underway: Then measure Lifetimes in BsDs
+-
etc….
Partially Reconstructed e.g. Bs +Ds-, B+ D0
1-lepton (+High IP track CDF )trigger: -Missing means: c= Lxy.MB/Pt
B =Lxy(D0+).MBK./Pt
(+D0)
-K= Pt(+D0) /Pt
B from MC: high statistics but worse c
Goal: test the HQE Predicted B Lifetime hierarchy : Bc << b0 ~ b < Bd ~ Bs < B- < b-
Physics Results, HQE: Bs J/, Lifetime and Mass:J/ +- , K+K- (using di-muon (J/) trigger): Run-I: ~60 at CDF. Run-II: D0~403, CDF~269 Largest sample of fully reconstructed Bs remains at the Tevatron
CDF:M(Bs)=5366.010.73(stat)0.0.33 (sys)MeV/c2 D0:M(Bs)=53605 MeV/c2
CDF: (Bs)=1.3470.0990.013 ps & Bs)/Bd)= 0.89 0.072 D0: (Bs) = 1.1900.180.014 ps (69 events, update in progress)
Mass & Lifetime Results from assorted other fully reconstructed decays:CDF: B)= 1.25±0.26±0.10 ps (bJ/), M(B)=5619.7±1.2±1.2 MeV/c2 Bs and B mass measurements remain worlds best..
Physics Results (aside): Bs width difference s
angular separation of CP eigenstatesCDF & D0 fit 1 lifetime But: there are 2: CP+,CP- & Bs=1/CP+-1/CP-
s: predicted to be large ~10%, provides SM consistency check: s=A.MBs If MBs is large & s is small or vice-versasign of new physics
Need to measure lifetime(s) : can do, and determine CP content: Use angular analysis…(CDF) and put them together (when we have higher statistics)Convenient basis: transversity Allows easy separation of CP content of BVV decays Analyse: Bs J/&Bd J/K* as a check(J/+-, K+K-, K*(892)K+-)
PDF has 3 angles: f() with amplitude parameters A,A A0
so that: A2=CP odd fraction & A2+A02
=CP even fraction
Physics Results (aside): Bs width difference s
angular separation of CP eigenstates
Polarization analysis indicates CP+ = 0.77±0.10: The larger the dominanceof a CP eigenstate the greater the accuracy of s Analysis will be done at D0 as well !
Using 176 BsJ/ & 993 BdJ/K*(892) (as a check)
Compatible with BaBar & Belle
Physics Results Testing HQE: Charged to Neutral B-Meson lifetime ratio (D0)
D0: Charged to Neutral B-Meson Lifetime Ratio: +/0 Use:-B D*(2010)-X: mostly Bd
-B D0X : mostly Bu±
-Calculate ratio of events/lifetime bin N+/N0 ~e-(+/0-1)t (K-factor)t
-Calculate expected ratio using all BRs in terms of k= +/0, and N(overall normalization)Minimize 2 determine k and D0 Result: +/0 = 1.093 ± 0.021 ± 0.022, =1.001±0.012
BaBar: B+)/Bd)= 1.064 ±0.031 ±0.026 CDF: B+)/Bd)= 1.080
0.042 Belle: B+)/Bd)= 1.091±0.023±0.014 (B+J/K+ & BdJ/K*0)
One of theWorld’s best singlemeasurements
Physics Results Testing HQE: More B decays used:bJ/ (CDF)
B+J/K+(D0)
BdJ/K* (D0)
B+J/K+
(CDF)
Physics Results: Hadronic Moments from D** decays1) HQE:(BXcll)~GF
2|Vcb|2 mb5.(Cn/mb)n with Cn = <0|On
HQE|0> (non-perturbative, can extract from data)
2) Free parameters at O(1/mb), 1+2 @ O(1/mb2) , etc….
3) Moments M1,M2 of Xc invariant mass distribution:
from B-decays :
have expansions similar to 1) i.e..in terms of 1+2 (sH=MXc2)
4) By finding pdf & hence M1, M2 ->constrain , 1 , & improve Vcb measurements
5) Now First 2 pieces from D*, D0 are well known. f** (sH) comes from narrow &wide D**+higher order(resonant & non-resonant):
max
min
max
min
2 21
2 2 2 22 1
1( )
1( ) ( )
H
H
H
H
ssl
H H HD Dssl H
ssl
H H H H Dssl H
dM ds s m s m
ds
dM ds s s s m M
ds
|Vcb|incl= (41.9 ± 0.7exp ± 0.6theo) 10-3
contains , 1
1 sl
sl H
d
ds
1 sl
sl H
d
ds
Physics Results : Hadronic MomentsReconstruct B- D**0 l- Find and D**0 consistent with B parent (vertex). Use lepton + high IP track data.
Reconstruct D**0D*+- & D**0D+ -
decays are reconstructed, moments: m1,
m2 calculated wrt f**(sH)
f**(sH) distribution
M1 M2 from D, D* & D**best single measurement !
In going from m to M assume:-lepton p in B rest frame >700 MeV-MD, MD* , Branching ratios from PDG-Only D** decays to 1 + D, D*
Rare B decays: B s(d)+- at CDF
-Use high-mass di-muon data-BRSM(Bs+- )=(3.8 ± 1.0) 10-9 some extensions predict x103 BRSM
- Variables: Mass, lifetime, from vertex & Isolation- 1 background event expected, 1 event seen: no excess->BR limit
“Blind” analysis: cuts optimization before looking at the signal mass region
BR Upper Limit at 95% CL 7.5x10-7 Bs (World’s best)1.9x10-7 Bd
BR Upper Limit at 90% CL 5.8x10-7 (Bs )1.5x10-7 (Bd )
Bd result: Belle: 1.6x10-7 & BaBar 2.0x10-7
Submitted to PRL
-Use MC for signal data, background for cut optimisation:-Expect 7.3 1.8 background events in signal region
Expected limit (Feldman/Cousins):
Br(Bs + -) < 9.1 10-7 @ 95 % CL (stat only)Br(Bs + -) < 1.0 10-6 @ 95 % CL (stat + syst)(expected signal has been normalised to B J/ K forBR limit calculation)
180 pb-1
The analysis has not been unblinded yet (signal region still hidden).
It is still being optimized (without bias) and expected to improve …
Physics Results Bs limits from D0:
Rare Decays: Bs :Observation & BR (SVT Trigger) CDF1) Bs decays via second order weak decay
2) SUSY coupling could enhance the SM BR (10-5)3) Comparison of angular distributions of various
B VV decays can determine and
BR= (1.4 ± 0.6 ± 0.2 ± 0.5 (BR))x10-5 (SM 3.7x10-5)
Upper Limit : <2.7x10-5 @ 95% CL
First “observation” (4.8) ! Blind analysis
1) Normalization Mode: BsJ/ 2) Relative Efficiencies from MC 3) N(Bs J/) is corrected for: Reflections from Bd J/K*4) J/ K+K- BsJ/BRstaken from PDG
s ss corr
s
N(B ) (B ). ( / )ε(ψφ)BR(B φφ)
N(B ) ε(φφ) ( )
φφ BR ψφ BR J
ψφ BR K K
Mixing and CP violation (CPV) in Bd,s decays, basics:
Same side taggingOpposite side tagging
Concept: Look for ± (K±) from hadronization of B (Bs)of interest, Higher
Concept:Look forB on opposite sideof B of interest -Look for ,e -Use weighted jet-charge Disadvantages: Opposite B not in acceptance (60%) or mixes (B0)
Issues: Tagging Flavour Correctly… ....& being able to tag at all
tagnowrongcorrect
wrongcorrect EfficiencyNNN
NN
wrongcorrect
wrongcorrectDilution NN
NND
Statistical power: N tagged events = D2N pure events
Check algorithms in known b-flavour decays eg B± J/K± Prepare for Bs mixing by first doing Bd mixing
-Mixing: tag B-flavour at birth, decay to flavour specific state: asymmetry: Amix~Cos(md,st)-CPV: tag B at birth, decay to CP eigenstate: asymmetry(t) Acpv~Acpv,direct.Cos(md,st)+Acpv,mixing.Sin(md,st)
Proof of principle: Bd mixing at D0 -Data sample: lepton triggers -Bd D*(2010)-X (D*-D0-,D0 K+-)-Find +, D0,- consistent with B-Select events within |M(D*-,D0)PDG- M(D*-,D0)|<0.04GeV/c2
-Opposite-side tags flavour -Use PDG BRs to calculate expected & observed asymmetry(t)-Md & Purity are free parameters & fit
250 pb-1
Preliminary results: md = 0.506 0.055 0.049 ps-1
Consistent with world average: 0.502 0.007 ps-1
Tagging efficiency: 4.8 0.2 % Tagging Purity: 73.0 2.1 % First D0 mixing Measurement !!
Proof of principle CDF (Run-II) Md measurement
First Run-II mixing result: same side tagging (SST)Find fragmentation from B, track near B with lowest relative PT B+J/ K+, D0+ to check tag, B0J/ K*0, D for md
CDF Run-I md (all methods) = 0.495 ± 0.026 ± 0.025 ps-1
-1.1KB0J/K*0
(J/data)-4.9K B0D (SVT Trigger!)Md=0.55±0.10 ps-1
Dilution (D) =12.4 %D2=1.0±0.5
Work on jet-charge & opposite side muonTagging continues
Physics Prospects: Toward Bs mixing at CDF : fully reconstructed decays : B0
s Ds
First observation of mode BsDs+-with (Ds+
, K+K-) ! “Flagship” Mode for Bs mixing !
Decays we plan to use:
B0s Ds
,
B0s Ds
Proper time resolution:
t = 67 fs t PT/PT
-Currently have reconstructed only Ds
-Reconstruct with more Ds decays eg: K*0K, +
to improve yields…
-Need to tag initial B flavour-projection awaits final D2
Physics Prospects: Toward Bs mixing semi-leptonic decays:
-Also Lifetime measurement provides valuable constraint on Bs:
=(cp+2+cp-
2 )/(cp++cp-) as in B0s Ds
Use leptons (CDF: lepton+high IP track) & select Bs+Ds-
X Find lepton+Ds-- K+K- lepton has charge opp.
to Ds
Plots have different mass resolution and S/B
Physics Prospects: CP violation in Bh+h- (SVT data) decays determining angle CDF), Method:
u-
bW
u
ud-
b dW
u,c,t
b su,c,t bW
us
W
Tree > penguin in B vice-versa in BsK+K-
MC
Lumi~180pb-
1
Bh+h- from hadronic triggerData ! (891 events)
1st Stage Statistically Separate Bd Bd K+Bs K+BsK+K-- Use: M vs =(1-p1/p2)q1:6 distinct shapes for +-
K+K-, (Bd,Bs) K+ K-
-Use: dE/dX distinguishes Ktoin the future use mBd mBs too…
dE/dx check: Use D*±D0, D0 K
Four unknowns In Asymmetry(t):d=ratio of penguin/tree hadronic matrix elementsphase of d = weak phases Constrain from B-factories, measure by fitting asymmetry (t)Proposed by: R.Fleischer, PLB459 1999 306
Physics Prospects: CP violation in Bh+h- decays determining angle CDF)
Results use 65 pb-1 sample, 1.16 dE/dX K separation:Update with dE/dX (1.4) & 180 pb-1
underway !
Yields (Results from 65 pb-1)BdBdKBsKBsK+K- BsK+K- First Observation !)Sanity check (spot on !): Measure Ratio of Branching Ratios
CDF : (Bd-)/(Bd K+-) = 0.26 ±0.11±0.055, PDG:
0.13 0.010.290.12 0.02
Finally we expect:
(Fleischer method) (2fb-1): () =±10(stat) ±3(syst SU(3) breaking)
Ratios of BRs (CDF) & ACP(Bd) (B-factories): Check SM consistency (D.London)
hep-ph/0404009
U-Spin relationship
SM check by comparison with ACP in Bd
58°<<72°
BR
(Bs
K+K
-
) BR
(Bd+-
)
ACP(Bd+-)dir
0.13 0.010.290.12 0.02
Conclusions:
1) CDF & D0 are completing 1st phase (~250pb-1) of data taking : a) Current (Bu
+)/Bd0) ) surpasses theoretical accuracy. Also
tests of vertexing & tracking (for future MBs and CPV) b) Search for FCNC set limits on rare BRs c) Prepare for Bs mixing: Establish by measuring Bd mixing
first !
2) Next phase (>250pb-1 &<500pb-1) will: a) set limits on (or observe) Bs mixing b) set limits on Bs
c) search for CPV in the neutral B system d) Continue to improve limits of Rare Decay BRs
3) Final Phase (end Run-IIa) (>500pb-1 and <2fb-1) all of the previous &:
a) Achieve better than 1% accuracy on (Bs)/Bd) ) & (Bd)/b))
b) Measure Bs mixing parameter xs expect to measure (s)~5%
c) Measure CKM angle d) ……and search for unexpectedly large CPV in Bs J/ Last phase will be mostly complementary to the B-factories
Backup Slides
Aside: Physics Results: Ratio of branching ratiosof BsDs
to BdD
Interest in BsDs is mostly due to Bs mixing but:we’ve also
measured the ratio of branching ratios (BsDs)/(BdD)
Normalization mode is BdD, D K
Kinematically ~BsDs, Ds
, K+K-
( ) ( ) ( ) ( )
( ) ( ) ( )s s s s s s
d d d d
N B f Br B D Br D Br K K
N B f Br B D Br D K
Ratio of Bs to Bd signals is:
Where are determined from Monte-Carlo
D, Ds BR are from PDG, obtain:
( )0.44 0.11( ) 0.11( ) 0.07( )
( )s s s
d d
f BR B Dstat BR syst
f BR B D
Using fs/fd =0.273±0.034 from PDG obtain:
( )1.61 0.40( ) 0.40( ) 0.26( ) 0.20
( )s s s
d d
BR B D fstat BR syst PDG
BR B D f
…we’re beginning to fill in PDG section on the Bs
Data Samples: B and Charm from the hadronic trigger
Prompt CharmD0K 86.5 0.4 % (stat)
D*D0 87.6 1.1 % (stat)
DK 89.1 0.4 % (stat)
Ds 72.4 3.4 % (stat)
0.5M Charm decays at CDF 10-20% come from B: Great Potential for B and Charm Physics, opens at least as many avenues as J/ trigger
Some charm is prompt
..to separate prompt Ds from Ds coming from B
An example of B reconstructed Using data from this trigger:
D from direct charm:Points back to beam spot
D from B has a impactParameter wrt beam spot
We have B and tons of Charm as well !
..Some charm is from B
Physics Results: Average B-hadron lifetime from partially reconstructed BJ/X decays
Results from D0 and CDF
B=1.5610.0240.074 ps D0 (40 pb-1)
B=1.5260.0340.035 ps CDF (18
pb-1)
Both consistent with: PDG: B = 1.564 0.014
D0 Inclusive B Lifetime
This is a “sanity check” of our BJ/sample: Obtain Average B hadron From all BJ/(+other stuff) decays: B is not fully reconstructed
Partially reconstructed B-Correct for missed daughters: F(PT) (from by Monte-Carlo)-B is an estimate -it is the average lifetime of all hadrons decaying to J/
( )xy
T T
Mct L
P F P
T
BT
BT P
P
M
MPF )(
Signal lifetime is modelled by :
Complete likelihood function:
( / )
( , , ) ( , )
( , , ) . ( , , ) (1 ). ( )
Bt
signal B t tB
B t signal B t background
eF t g t
F t f F t f F t
Complete event probability density
Background shape from side-bands
Bs width difference s and angular variable separation
Two CP states: lifetime
Two CP states: transversity
Total function and normalization
21
22
( ,1) 0.375(1 cos )
( , 2) 0.75(sin )
F
F
1 1 1 2( , , ) [ . ( , , ). ( ,1) (1 ). ( , , ). ( , 2)]. ( , , )signal CP t B CP t B m BF m t f F t F f F t F F m M
( , , ) . ( , , ) (1 ). ( , , )total s signal s backroundF m t f F m t f F m t ( , , ) 1totalF m t dmdtd
1
2
( / )
1 11
( / )
2 22
( , , ) ( , )
( , , ) ( , )
B
B
t
t B tB
t
t B tB
eF t g t
eF t g t
Current limit (LEP): s / s <0.31, from branching ratio of BsDs±(*)Ds(*)
Note: SM CP violation in this mode: O(3%), if large new physicsCP asymmetry = sin2 s, measured= s,SM.Cos2complementary)
One lifetime(width) has been fit in this mode
1) But contains two distinct lifetimes: CP+ & CP- Bs, significant lifetime (width) difference:
s=1/B1-1/B2
2) Extract s : fit two lifetimes, use single angle to separate CP+ and CP- Bs: (Transversity angle
3) SM prediction for s ~0.10s also s = A.xs (xs = Bs mixing parameter) if s is small and xs is large or vice-versa Sign of new physics
3) CDF prediction for 2fb-1 (s)~0.05
Physics Results: lifetime, mass, from fully reconstructed B J/ X modes: Standard Technique :
Data from J/ di-muon trigger: 1) Reconstruct vertex according to decay topology2) Calculate decay proper time mass & errors3) If fitting for mass:fit mass only4) If fitting for lifetime:Fit mass and lifetime using bi-variate Probability density function (PDF) in likelihood
2
2
( / )
( )( )
( , , ) ( , )
( , , )2
( ) ( , , )
( , ) ( , , ). ( , , )
( , ) . (1 ). ( , )
( , ) 1
B
B
m
t
t B tB
m M
m B
m
signal m B
signal t B m B
total s signal s backround
total
eF t g t
eF m M
F m F m M
F m t F t F m M
F m t f F f F t m
F m t dmdt
1) Signal Lifetime :
2) Signal Mass :
4) Signal pdf in mass and lifetime:
6) Normalization : mass & lifetime
3) Signal for Mass only analyses:
5) Signal for lifetime analysis:
An Example B+ ->J/ K+ at CDF
Both the mass and lifetime distributions are fit in a single step. Technique is applied to :
B+ J/ K+, B0 J/ K0* (K0* K),
Bs J/ ( KK), bJ/ (p)
Probability Density Function (pdf)
B physics prospects(with 2fb-1)
Bs mixing: Bs →Dsπ(Ds3π) (xs up to 60, with xd meas. one side of U.T.)
Angle : B0→ J/ψ Ks (refine Run1 meas. up to (sen2) 0.05)
CP violation, angle γ : B0→ ππ(πK), Bs → KK(Kπ)
Angle s and s/ s : Bs→ J/ψ (probe for New Physics)
Precise Lifetimes, Masses, BR for all B-hadrons: Bs, Bc, Λb … (CDF observed: Bc → J/ψ e(). Now hadronic channels Bc → Bs X can be explored)
HF cross sections (beauty and charm)
Stringent tests of SM … or evidence for new physics !!
Both competitive and complementary to B -factories
Physics Results: Average B-hadron lifetime from partially reconstructed BJ/X decays.
Results from D0 and CDF
B=1.5610.0240.074 ps D0 (40 pb-1)
B=1.5260.0340.035 ps CDF (18
pb-1)
Both consistent with: PDG: B = 1.564 0.014
D0 Inclusive B Lifetime
This is a “sanity check” of our BJ/sample: Obtain Average B hadron From all BJ/y (+other stuff) decays: B is not fully reconstructedIf Fully reconstructed B-ct = c.(time in B rest frame)-Lxy = 2-d decay length-MB = mass -PT = transverse momentumIf Partially reconstructed B-Correct for missed daughters: F(PT) (from by Monte-Carlo)-B is an estimate -it is the average lifetime of all hadrons decaying to J/
( )xy
T T
Mct L
P F P
T
BT
BT P
P
M
MPF )(
B
xy BT
Mct L
P
Signal lifetime is modelled by :
Complete likelihood function:
( / )
( , , ) ( , )
( , , ) . ( , , ) (1 ). ( )
Bt
signal B t tB
B t signal B t background
eF t g t
F t f F t f F t
Complete event probability density
Background shape from side-bands
Sin(2) in B0J/Ks
N(B0)(t) - N(B0)(t)
N(B0)(t) + N(B0)(t)=Dsin(2)sinmd
tACP(t) =
N(J/ Ks) from scaling Run I data:• x 20 luminosity
8,000• x 1.25 tracks at L1 trigger 10,000• x 2 muon acceptance 20,000• Trigger on J/ e+e + 10,000
In Run1 measured:
sin(2)=0.79±0.39±0.16
B0 J/ Ks ; J/
(400 events)(+60 B0 (2S) Ks)
sin(2)=0.91±0.32±0.18
Combined D2: from 6.3% to 9.1% (Kaon b-tag)
Same S/B = 1
Expect: s(sin2b) 0.05
With 2fb-1 can refine this measurementAlthough: no way to compete with B-Factories !
)) (2 sin( S B
ND1
2
1Stat. Error:
Systematic ~ 0.5xStatistical
(scales with control sample statistics)
ms/md
Tevatron Performance
July ‘01
Now
Tevatron operations • Startup slow, but progress steady !
• Now: L ~3.5 x 1031 cm-2s-1
integrating ~ 6. pb-1/week• … still factor 2-3 below planned valuesadditional improvements (~10-20%) expected from Jan. 3weeks shutdownCDF operations
• Commissioning: Summer 2001• Physics data since February 2002• Running with >90% Silicon integrated
since July 2002
Initial Luminosity3.8 x 1031
110 pb -1
July ‘02
On-tape Luminosity
Luminosity (on-tape): ~20pb-1 until June (analyses in this talk) Additional 90pb-1 July – December Reach 300- 400 pb-1 by October 2003
Feb ‘02
Quadrant of CDF II Tracker
LAYER 00: 1 layer of radiation-hard silicon at very small radius (1.5 cm) (achievable: 45 fs proper time resolution in Bs Ds )
COT: large radius (1.4 m) Drift C.
• 96 layers, 100ns drift time • Precise PT above 400 MeV/c
• Precise 3D tracking in ||<1
(1/PT) ~ 0.1%GeV –1; (hit)~150m
• dE/dx info provides 1 sigma K/ separation above 2 GeV
SVX-II + ISL: 6 (7) layers of double-side silicon (3cm < R < 30cm)• Standalone 3D tracking up to ||= 2• Very good I.P. resolution: ~30m (~20 m with Layer00)
TOF: 100ps resolution, 2 sigma K/ separation for tracks below 1.6 GeV/c (significant improvement of Bs flavor tag effectiveness)
TIME OF FLIGHT
CDF II Trigger System3 levels : 5 MHz (pp rate) 50 Hz (disk/tape storage rate) almost no dead time (< 10%)
XFT: “EXtremely Fast Tracker” 2D COT track reconstruction at Level 1
• PT res. pT/p2T = 2% (GeV-1)
• azimuthal angle res. = 8 mrad
SVT: “Silicon Vertex Tracker” precise 2D Silicon+XFT tracking at Level 2
• impact parameter res. d = 35 m
Offline accuracy !!
CAL COT MUON SVX CES
XFT XCES
XTRP
SVTL2
CAL
L1CAL
GLOBALL1
L1MUON
L1TRACK
GLOBALLEVEL 2 TSI/CLK
CDF II can trigger on secondary vertices !! Select large B,D samples !!
Matched to L1 ele. and muonsenhanced J/ samples
SVT: Triggering on impact parameters
d
beam spot
COT track ( 2 parameters) 5 SVX coordinates
Impact Parameter (transverse projection)
• Combines COT tracks (from XFT) with Silicon Hits (via patternmatching) • Fits track parameters in the transverse plane (d, , PT) with offline res.• All this in ~15s !• Allows triggering on displaced impact parameters/vertices• CDF becomes a beauty/charm factory
~150 VME boards
B triggers: conventional
Suffer of low BR and not fully rec. final state
Need specialized triggers(bb) / (pp) 10-3
CDF Run1, lepton-based triggers:
Di-leptons (, PT 2 GeV/c): B J/ X, J/ Single high PT lepton ( 8 GeV/c): B l D X
Now enhanced, thanks to XFT (precise tracking at L1) :• Reduced (21.5 GeV/c) and more effective PT thresholds • Increased muon and electron coverage• Also J/ ee
Nevertheless, many important measurements by CDF 1: B0
d mixing, sin(2), B lifetimes, Bc observation, …
XFT performance
XFT: L1 trigger on tracks better than design resolution
pT/p2T = 1.65% (GeV-1)
= 5.1 mrad
XFT track
Offlinetrack
Efficiency curve: XFT threshold at PT=1.5 GeV/c
= 96.1 ± 0.1 % (L1 trigger)
53.000 J/
11 pb-
1
SVT performance
D0 K used as online monitor of the hadronic SVT triggers
I.P. resolution as planned
d = 48 m = 35 m 33 m
Efficiency
80%
90%
soon
transverse beam size
intrinsic
S/B 1
TOF performance TOF resolution (110ps)
within 10% of design value
with TOF PID
S/N = 1/40
S/N = 1/2.5
Background reduction in KK:Low PT (< 1.5 GeV/c) track pairsbefore and after a cut on TOF kaon probabilityx20 bkg reduction, 80% signal efficiency
CDF J/cross section
0<pt<0.25
GeV 5.0<pt<5.5 GeV10.0<pt<12.0 GeV
(ppJ/; pT>0; ||<0.6) =240 1 (stat) 35/28(syst) nb
Lots of charm from hadronic triggers:
Foresee a quite interesting charm physics program:• D cross sections, • CP asymmetries and Mixing in D sector, Rare decays, …
56320490
K mass
D0 K
KK mass mass
D0 KK D0
5670180 2020110
(DKK)/(DK) = 11.17 0.48(stat) 0.98 (syst) %(D )/(DK) = 3.37 0.20(stat) 0.16(syst) %
Relative Br. Fractions of Cabibbo suppressed D0 decays :
Already competitivewith CLEO2 results(10fb-1 @ (4S))
!!!!!
With ~10 pbWith ~10 pb-1-1 of “hadronic trigger” data: of “hadronic trigger” data:
O(107) fully reconstructed decays in 2fb-1
B0s mixing: expectations with
2fb-1
Signal: 20K ( only) - 75K (all) events• with SVT hadronic trigger
• BR (Ds ) = 0.3 % ; BR (Ds ) = 0.8 %
Resolution: (c) = 45 fs (with Layer00)
D2 = 11.3% (with TOF)
S/B: 0.5-2 (based on CDF I data)
5 sensitivity up to:
Xs = 63 (S/B = 2/1)
Xs = 53 (S/B = 1/2)
S.M. allowed range: 20. < Xs < 35.
Can do a precise measurement… or evidence for new physics !
xs = ms(B0s)Bs Ds, Ds
Ds , K*K,
2( m )22
1 1 S B( x )
N D Ss t
s e
Data Samples: The J/ t CDF and D0 (Run-II)
0.5M at CDF (70 pb-1) 75K at D0, completely new capability ! (40 pb-1)
Two Fully Reconstructed B-hadronJ/states at CDF &D0
BJ/ KS: CDF:220, D0:45 (Run-II) (D0 had none in Run-I)
BJ/ : CDF:53, D0:16 (Run-II)
Data Samples: B and Charm Using the high Impact Parameter (IP) (Hadronic) trigger
Select events by requiring : -2 tracks with IP>100 m - track PT > 2GeV/c - sum 2-track PT > 5.5 GeV/c
0.5M Charm decays at CDF 10-20% come from B: Great Potential for B and Charm Physics, opens at least as many avenues as J/ trigger
Data Samples: B(+)l+D decays using “hybrid” triggerSelect events with 1 lepton (PT>3 GeV/c) & 1 high IP (>120m)track:-High IP track means we can go lower in lepton PT ->Much higher than Run-I due to lower PT thresholds (x4-5 increase)
Used for:1) High statistics lifetime and mixing analyses 2) calibration samples for tagging (B+l+D) Drawback: worse vertex resolution due to missed neutrinoSome numbers:BlD0X (D0K): ~10000 events, BlD+X (D+K): ~5,000 events also Bs decays (later)
Use new “hybrid” displaced track+single lepton trigger
Decays included: Accounting for missed neutrino
Bs Dsl, Ds*l (Ds
, K*0K, +)
expect ~40K events in 2 fb-1
t is worse due to missed (K factor) :
t = 60 fs t K/K, K/K ~ 14%
If one Bs lifetime is fit in any flavour specific mode:
fit = (BsCP+2+BsCP-
2)/(BsCP++BsCP-) from which s can be determined as well
Carlo Monte from )(
)(
)(
)()(
)(
)()(
st
st
st
ssxy
st
ssxy
BP
DlPK
KDlP
BMBL
BP
BMBLct
Physics Results: Lifetimes from partially reconstructed decay
Physics Results: B, lepton+displaced track and purely hadronic data samples (have shown J/ mode already)b cl [pK] l Protons are easiest to separate using Time of Flight
Particle ID in left plot using TOF and dE/dX
b c [pK] Lifetime in hadronic, hadron+lepton modes require
correction for IP cut bias & missing Expect results after this summer
Note on B
A search for CP violation in Baryon decays is plannedusing Bp
Mixing and CP violation (CPV) at Hadron colliders Proof of principle:
Run-I, CDF were able to do 2 measurement of sin2 & competitive xd (md/) measurements: can tag b-flavours in hadron collider environment
Sin2=0.79±0.39(stat)±0.16(sys) (CDF 1996)CDF have not repeated this measurement yet…cannot compare to B-factories…
CDF: In Run-II with 40-50 x more BdJ/KS
decays can get (sin2)~0.05: D0: Similar statistics
Can’t be competitive with BaBar (insert current) and BELLE (insert current)Redo the measurement because:-It’s an important benchmark -Gives credence to other CPV measurements eg. in Bh+h- & BsJ/
Physics Results: Charm physics at CDF: Search for CP violation (CPV) in Charm decays:1) c and u quarks don’t couple to t box diagram contributions are tiny2) CPV in charm decays due to interference in decay (direct CPV) 3) SM prediction O(0.1-1%) CP violation effects in Charm Decays
How: Compare rate of Decay of D0, D0 to CP eigenstates f=K+K- and +-
0 0
0 0
( ) ( )
( ) ( )CP
D f D fA
D f D f
Method Using data from Hadronic Trigger-Collect D*±D0± : sign of tags flavour of D-Search for D0 K+K-, D0 +-, D0 +- & D0 K+K- -Correct for tracking efficiency for + vs - from D*±D0±
-Count number of decays in each mode after corrections
CPV in charm decays
…8320 D*±D0±, D0 K+K-
First CPV measurement at CDF in Run-II
93560 D*±D0±
with D0+-
Cross-check: Measure Ratio of Branching Ratios @CDF(D0 +-)/(D0 +-)=9.38±0.18±0.10% (D0 +-)/(D0 +-)=3.686 ± 0.076 ±0.036%
FOCUS: (D0 +-)/(D0 +-)=9.93±0.14±0.14% (D0 +-)/(D0 +-)=3.53±0.12±0.06%CDF accuracy is comparable and consistent with FOCUS (2003) and World average 2.88±0.15 (PDG)
ACP(D0 (+-))=2.0±1.7±0.6% (PDG 0.5±1.6%)ACP(D0 (+-))=3.0±1.9±0.6%(PDG 2.1±2.6%)
CLEO Result (2001)
ACP(D0 (+-))= 0.0±2.2±0.8%
ACP(D0 (+-))= 1.9 ±3.2±0.8%
Physics Results: Search for Flavour Changing Neutral Current decay D0+-
SM predicts a branching ratio (BR) of O(~10-13) for D0+-
Some R-parity violating SUSY models predict branching ratios upto O(~10 -6)
CDF Result: BR(D0+) 2.4x10-6 better than most recent world average:( PDG 90%CL: < 4.1 x 10-6 )
Technique:1) D0+- BR is well known ~ identical
acceptance to D0 +-
2) Use D0*± D0± to tag D0 in D0K-+ (thus no K
vs ambiguity)3) See how many s fake s per PT
5) Look for D0 +- in same sample6) Subtract D0+- faking D0+-
0 events found in 2searchwindow
Physics Results,Testing HQE: A summary of results:
D0 (240 pb-1): (B+)/(B0) = 1.093±0.021± 0.022 ps (from semi-leptonics)
CDF (240 pb-1): (B+ )= 1.660.030.01 ps, (B0 )=1.54 0.050.01 ps
B+)/Bd)= 1.080 0.042 (B+J/K+ & BdJ/K*0)
Bs)/Bd)= 0.89 0.072(Bs J/) B)= 1.25±0.26±0.10 ps (bJ/) CDF Mass Measurements: M(Bs)= 5366.01 0.730.33 MeV/c2 World’s best measurements M(B)= 5366.01 0.731.2 MeV/c2 of Bs &B masses……………BELLE (PRL 88 171801 2002)
using BdD(*)-(+), J/KS,J/K*0 and B+D0+, J/K+
B+)/Bd)= 1.091±0.023±0.014BABAR : fully reconstructed decaysBdD(*)-(+,a1
+), J/KS,J/K*0 and B+ D0+, J/K+
B+)/Bd)= 1.082±0.026±0.012 BABAR : partially reconstructed decays(BD,D* l )B+)/Bd)= 1.064 ±0.031 ±0.026
HQE Predicted B Lifetime hierarchy :
Bc << b0 ~ b < Bd ~ Bs < B- < b-
Physics Results: Charm physics at CDF: Search for CP violation (CPV) in Charm decays:
1) c and u don’t couple to t box diagram contributions are tiny2) CPV in charm decays due to direct CPV SM~O(0.1-1%) CPV, good test of SM !How: Compare N(D0), N(D0)to CP eigenstates K+K- & +-
0 0
0 0
( ) ( )
( ) ( )CP
D f D fA
D f D f
Data from SVT: 1) Find D*±D0± : sign of tags flavour of D, 2) Find D0 K+K-, D0 +-, D0 +- & D0 K+K-
1) Cross-check:Ratios of BRs (@CDF):(D0 +)/(D0+)=9.38±0.18±0.10% & (D0 +-)/(D0 +-)=3.686 ± 0.076 ±0.036FOCUS: 9.93±0.14±0.14% & 3.53±0.12±0.06% CDF consistent with FOCUS & PDG 2.88±0.15
First CPV result at CDF in Run-II
AD0 +-
=2.0±1.7±0.6% AD0+-
=3.0±1.9±0.6%CLEO Result (2001) & PDG
AD0+- = 0.0±2.2±0.8%
AD0+- = 1.9 ±3.2±0.8%
(0.5±1.6 & 2.1±2.6%)
Physics Prospects: CP violation in Bh+h- decays determining angle CDF)
Bh+h- from hadronic triggerIncludes B Bs K+K-
Bs K, and Bd K
Monte-Carlo:Bd Bs K+K- Bs K,
& Bd K (From Monte-Carlo)-all pile up
Must disentangle each mode from signalWe (will) use: -dE/dx based K and ID -Kinematical variable: M vs =(1-p1/p2)q1
-Width of signal -Frequency of oscillation in CP asymmetry
Physics Prospects: CP violation in Bh+h- decays determining angle CDF), Method:
u-b
W
u
ud-
b dW
u,c,t
b su,c,t bW
us
W
Five observables,
Four unknowns:d=ratio of penguin/tree hadronic matrix elementsphase of d = weak phases
Constrain Sin2 from B-factories, & CDF/D0 results and measure
Tree and penguin graphs for B & Bs K+K-
-CP Asymmetry in B = Sin2() (without penguin) -CP Asymmetry in Bs K+K- = Sin2without penguin) -Assume SU(3) symmetry: replace sd Hadronic matrix element ratios : penguin/tree same for both modes
Tree > penguin in B vice-versa in BsK+K-
Proposed by: R.Fleischer, PLB459 1999 306
Physics Prospects: CP violation in Bh+h- decays determining angle CDF)
Numbers from 65 pb-1 sample & 1.16 dE/dX separationUpdate from re-calibrated dE/dX (1.4) & 180 pb-1 in progress
Yields (Results from 65 pb-
1)BdBdKBsKBsK+K- BsK+K- First Observation !!)
M vs a for each Bh+h- mode
Sanity check: Measure Ratio of Branching RatiosCDF : (Bd-)/(Bd K+-) = 0.26 ±0.11±0.055, PDG: 0.13 0.010.29
0.12 0.02
Fleischer method: Expect (2fb-1): () =±10(stat) ±3(syst SU(3) breaking)
Ratio of BRs along with ACP(Bd ) from B-factoriesHelps constrain
hep-ph/0404009
U-Spin relationship
SM check by comparison with ACP in Bd
58°<<72°
BR
(Bs
K+K
-
) BR
(Bd+-
)
ACP(Bd+-)dir
Physics Results, Testing HQET: lifetime, mass, from fully reconstructed B decays modes, Technique :
Data from J/ di-muon trigger or High IP trigger: - Reconstruct vertex - Calculate decay proper time, mass & errors- Mass:fit mass distribution only- Fitting for Lifetime:Fit mass and lifetime distributions in single step
Technique applied to several decays : B+ J/ K+, B0 J/ K0* (K0* K), Bs J/ ( KK) & bJ/ (p)…etc
( , ) . ( , ) (1 ). ( , )
( , ) 1
total s signal s backround
total
F m t f F t m f F t m
F m t dmdt
Probability Density Function and normalization:
-Those Decays selected usingSVT trigger have biased c(Also lepton+high IP track data@CDF)-Fix bias and then measureLifetimes in Bs Ds
+-, and other purely hadronic decays
High IP track selection efficiency
Physics Results,Testing HQE:Lifetime, mass summary:
D0 (240 pb-1): (B+)/(B0) = 1.093±0.021± 0.022 (from semi-leptonics)
CDF (240 pb-1): (B+ )= 1.660.030.01 ps, (B0 )=1.54 0.050.01 ps
B+)/Bd)= 1.080 0.042 (B+J/K+ & BdJ/K*0)
Bs)/Bd)= 0.89 0.072(Bs J/) B)= 1.25±0.26±0.10 ps (bJ/) CDF Mass Measurements: M(Bs)= 5366.01 0.730.33 MeV/c2 World’s best measurements M(B)= 5366.01 0.731.2 MeV/c2 of Bs &B masses……………BABAR : exclusive decays BABAR : inclusive decays B+)/Bd)= 1.082±0.026±0.012 B+)/Bd)= 1.064 ±0.031 ±0.026
BELLE B+)/Bd)= 1.091±0.023±0.014
HQE Predicted B Lifetime hierarchy :
Bc << b0 ~ b < Bd ~ Bs < B- < b-
-Projection: (Bs)/Bd) ) & (Bd)/b)) <1% at 2fb-1
-Current (Bu+)/Bd
0) ) surpasses theoretical accuracy
-Measurements test vertexing & tracking: Crucial for MBs and CPV
Physics Results: Rare B decays: B s(d)
-No observed excess -Expected backgrounds (events): 1.050.3 (Bs) and 1.07 0.31 (Bd)-Observed 1 event for both modes branching ratio limit is possible-SM Prediction BR~10-9
Bs result surpasses previous worlds best result (by x2 CDF)
BR limits vs. luminosity
Bd result: bit better than Belle (1.6x10-7) and BaBar (2.0x10-7)
Submitted to PRL
BR Upper Limit at 95% CL 7.5x10-7 (Bs )1.9x10-7 (Bd )
BR Upper Limit at 90% CL 5.8x10-7 (Bs )1.5x10-7 (Bd )
Rare Decays: Bsbranching ratio:
Calculate Branching ratio using corrected Ncorr(Bs J/:
s ss corr
s
N(B ) (B ). ( / )ε(ψφ)BR(B φφ)
N(B ) ε(φφ) ( )
φφ BR ψφ BR J
ψφ BR K K
s ss
s
N(B ) (B ). ( / )ε(ψφ)BR(B φφ)
N(B ) ε(φφ) ( )
φφ BR ψφ BR J
ψφ BR K K
1) Approach: calculate branching ratio by using N(Bs J/)in the same data (SVT triggered) sample:
SM Prediction for branching ratio: 3.7x10-5 hep-ph/0309136BR= (1.4 ± 0.6 (stat) ± 0.2(syst) ± 0.5 (BR))x10-5
Upper Limit : BR= (1.4 ± 0.6 (stat) ± 0.2(syst) ± 0.5 (BR))x10-5
1) All BRs are taken from PDG2) Efficiencies calculated from MC 3) N(Bs J/) is corrected for: a) Reflections from Bd J/K*(892) b) Requirement of a muon match (check of signal in SVT data)
Physics Results : Hadronic Moments Calculating : D, D* are known , measure only f**, contains wide and narrow D**0 and non-resonant part. Reconstruct only B- D**0 l- (0s not possibe @ CDF). Find and D**0 consistent with coming from B (vertex), Mass<5.3 GeVD**0 D+, D*+, D*00, reconstruct or use Isospin for Mass pdf
1 sl
sl H
d
ds
Using Lepton+High IP data:A) D**0 D*+ -
B) Can’t do D**0 D0 0
But = 0.5A & same shape
C) D**0 D+ - D) D*+ D0 + E) D*+ D+ 0 Can’t do: Feed-
down to D+ - & is corrected for.
F) D**0 D*0 0 Can’t do but = 0.5.A (same shape)
Physics Results: Hadronic Moments analysis
42
12
**2
22**1
69.030.1
16.083.5
GeVmmm
GeVmm
D
D
D**0 mass distribution…. ….gives moments wrt D**0 only
Moments from all D, D*
And finally from M1 & M2 we get:
Best single measurementOf M1 M2 in the world !
Physics Prospects: CP violation in Bh+h- decays determining angle CDF), Method:
u-
bW
u
ud-
b dW
u,c,t
b su,c,t bW
us
W
Tree > penguin in B vice-versa in BsK+K-
MC
Lumi~180pb-
1
Bh+h- from hadronic trigger
Problem: Separating Bd Bd Bs
Bs Use M vs =(1-p1/p2)q1, dE/dX, to separateBd Bd Bs Bs in the futureWill use oscillation frequencies as well……
dE/dx check: Use D*±D0, D0 K
Four unknowns In Asymmetry(t):d=ratio of penguin/tree hadronic matrix elementsphase of d = weak phases Constrain Sin2 from B-factories, & CDF/D0 results and measure by fitting asymmetry Proposed by: R.Fleischer, PLB459 1999 306
Toward Bs Mixing: Proof of principle CDF (Run-II) Md
First Run-II result: Bd-Bd oscillations using same side tagging (SST)Look for fragmentation from B, track with lowest relative PT to B -Use B+J/ K+ (J/ data) & B+D0+ (SVT data) to tune
tagging -Use B0J/ K*0( K)and B0D to measure md
Flavour Tagging-Look for fragmentation from B-Calculate Pt
rel variable-Want maximally collinear B and -Pick candidate with lowest Pt
rel -B flavour is correlated with sign
CDF Run-I md (all methods) = 0.495 ± 0.026 ± 0.025 ps-1
Physics Prospects: CP violation in Bh+h- decays determining angle CDF), Method:
u-
bW
u
ud-
b dW
u,c,t
b su,c,t bW
us
W
Tree > penguin in B vice-versa in BsK+K-
MC
Lumi~180pb-
1
Bh+h- from hadronic trigger
Problem: Separating Bd Bd Bs
Bs Use M vs =(1-p1/p2)q1, dE/dX, to separateBd Bd Bs Bs in the futureWill use oscillation frequencies as well……
dE/dx check: Use D*±D0, D0 K
Four unknowns In Asymmetry(t):d=ratio of penguin/tree hadronic matrix elementsphase of d = weak phases Constrain Sin2 from B-factories, & CDF/D0 results and measure by fitting asymmetry Proposed by: R.Fleischer, PLB459 1999 306
Examples of decays: Accounting for missed neutrino:
Bs Ds-l+, Ds*-l (Ds
++, K*0K+, ++)
Bu- D0l-, D0l- X (D0 +K-)
Advantage: Very high statistics
Drawback: t is worse due to missed (K factor)
However: Large numbers provide opportunities for lifetime & mixing
Physics Results Testing HQE: Lifetimes from partially reconstructed decays
Data are selected using high PT leptons (D0) & lepton+high IP track (CDF)
D0: Charged to Neutral B-Meson Lifetime Ratio: +/0
-B D*(2010)-X decays: mostly Bd
-B D0X decays: mostly Bu±
-Calculate ratio of events/lifetime bin-Account for all decays BRs (PDG) -ratio of events expected : ~N+/N0 ~e-(+/0-1)t (K-factor)t
D0 Result: +/0 = 1.093 ± 0.021 (stat) ± 0.022 (syst) Competitive with worlds best results
0
0
( ) ( ) ( ) ( )
( ) ( )
( ) from Monte Carlo
( )
xy u u xy u u
t u t
t
t u
L B M B L B M Bct K
P B P l D
P l DK
P B