Transcript Local Muon reconstruction for P13

Selected DØ Physics Results
for ICHEP 2006
Andrzej Zieminski
Indiana University
for the
Collaboration
W&C, Fermilab, June 21, 2006
Approach
• concentrate on results never presented before to this
audience, many approved this week.
• results will be sorted by physics groups
• only a fraction of the results will be presented
• a comprehensive list of all results improved, finalized
and preliminary since Winter Confs. will be provided
• Recent W&C from D0:
–
–
–
–
–
7/21/2006
Guennadi Borrisov, B-states & dimuon asymm. Mar. 3
Sergei Burdin, Bs mixing
Mar. 24
Gregorio Bernardi, Higgs searches
May 5
Patrice Verdier, SUSY results
June 9
Andrew Askew, Diboson physics
June 23
D0 Results for ICHEP
2
D0 Detector & its Performance
Multipurpose.
Silicon microvertex tracker
Central Fiber Tracker
Axial solenoid
Muon ID; || < 2
Tracking acceptance || < 3
7/21/2006
D0 Results for ICHEP
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QCD/EWK physics: recent analyses
• Inclusive jet cross sections
• W asymmetry
0.8 fb-1
0.2 fb-1
- Zg x-section
0.4 fb-1
- X Zg searches
0.4 fb-1
- Zg x-section & anomalous couplings eeg (mmg) ~ 1 fb-1
- WW x-section
- WW anomalous couplings
0.2 fb-1
0.2 fb-1
- First evidence for WZ production
0.8 fb-1
• Z pT measurement (ee)
0.8 fb-1
7/21/2006
D0 Results for ICHEP
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Inclusive jet cross sections
• Theory @NLO is reliable (±10%)
 Sensitivity to PDFs
 Unique: High-x Gluon
• Run II: s increased x5 at
pT=600 GeV
 Sensitive to New Physics:
Compositeness, LED, …(?)…
DØ - midpoint cone algorithm
7/21/2006
D0 Results for ICHEP
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Run I and Run II so far…
Good agreement of theory and data over large pT & √s range
7/21/2006
D0 Results for ICHEP
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W Charge Asymmetry
Typically the u quark carries more of
the proton momentum  W+ is
boosted in the direction of the proton
Isolated m, pT > 20 GeV,
MET > 20 GeV, MT > 40 GeV.
L=230pb-1
Charge mis-id = 0.01% (Z-data,
m momentum measured twice)
Yellow band: CTEQ uncertainty
Blue MRST02 central value
0.005 < x < 0.3
7/21/2006
D0 Results for ICHEP
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WZ production
Direct probe of the WWZ Trilinear Vertex
●
●
●
●
●
●
Select 2 leptons (ee,mm) pT > 15 GeV.
MET > 20 GeV
Additional high pT lepton
Reject top events by ETHAD < 50 GeV.
Instrumental bkgd: Z+j from data
Physics bkgd: ZZ, Top, W+DY
s = 3.9 +1.9 -1.5 pb
sSM = 3.7 ± 0.3 pb
First evidence for
WZ production (3.3s)
7/21/2006
D0 Results for ICHEP
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Top physics: recent
analyses
• Top pair x-section
-
All jets
lepton+track & e+m
• Top Quark mass
- lepton+jets
-
lepton+jets
lepton+jets
em
-
em
lifetime tag & topol
lifetime tag & topol
370 pb-1
370 pb-1
Matrix, in situ JES , b- tag
Matrix, in situ JES , topology
Ideogram , b-tag & topology
Matrix weighting
Neutrino weighting
370 pb-1
370 pb-1
370 pb-1
835 pb-1
835 pb-1
• Other top properties
-
Right-handed W’s
W’ search
7/21/2006
370 pb-1
230 pb-1
D0 Results for ICHEP
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All jet
M(jj)
M(bjj)
High yield, high BG
Data with final selection
(with b-tagging)
Background
From data
+ Data
Pythia tt 175GeV
Background substracted
360/pb
12.1  4.9(stat)  4.6(syst)pb
7/21/2006
D0 Results for ICHEP
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Summary of
RunII top cross
section results
7/21/2006
D0 Results for ICHEP
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Top Mass in lepton+jets channel
using ideogram method
l
W+
b-jet
n
t
t
b-jet
Cuts: pt>20 GeV, MET>20 GeV,
≥4j ( pt>20, ||<2.5)
W-
jet
jet
Mjj(W)
Ideogram method:
Event by event likelihood based on
kinematic fit. Includes all possible
assignments of jets, and possibility of
background,
Lifetime-based id of b-jets when available
JES in situ calibration
7/21/2006
D0 Results for ICHEP
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Top mass measurements in em
835 pb-1
Unconstrained system: 2 neutrinos, 18 kinem. Quantities, 14 measured+3 constraints
28 events seen, expected: 20.2±2.7 ttem, 4.4±2.6 bkg (WW, Ztt, fake
e)
Matrix element weighting:
:
For each event find mpeak for which
solution weight is maximum
Compare observed mpeak
distributions to combined signal and
bkgd templates
Neutrino weighting technique:
Start by ignoring observed missing ET
Assume top mass and η for each n &
extract n 4-momenta. Weight each solution
Event weight vector – 3 different methods
Max likelihood fit of weight vectors to MC templates
7/21/2006
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Summary of top mass measurements
7/21/2006
D0 Results for ICHEP
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B - physics recent analyses
All based on ~1 fb-1 data
• Bs mixing in Bs  Ds-m+X (Ds-  fp)
PRL 97 (2006) 021802, July 14
• Bs mixing in Bs  Ds-m+X (Ds-  K*0K-)
• Bs mixing in Bs  Ds-e+X (Ds-  fp)
• Lifetime difference and Mixing Phase in the Bs system
• Time-integrated asymmetry in semileptonic Bs decays
• CP – violation parameter of B0 mixing from dimuon charge asymmetry
• BF(BsDs(*)Ds(*))
• Bd** production fractions
• Bd** mass splitting
• direct observation of Bs**
• measurement of BsDs** m n
• limit on D+p+m+m7/21/2006
Either first or
best measurements
D0 Results for ICHEP
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Bs - an entangled system
•Bs system is strongly mixed;
•Two physical states BsH
(heavy) and BsL (light) have
distinct masses and lifetimes:
M  M H - M L  2 M 12 ;
    L -  H  2 12 cosf s ;
 M 12 
;
f s  arg  12 
7/21/2006
M12 and Γ12 are elements
of complex mass matrix
(M - iΓ/2) of Bs system;
f s- CP violating phase;
fs(SM)= O(|Vus|2 mc2/mb2) ~ 5·10-3 = 0.3º
D0 Results for ICHEP
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ms limit from Log Likelihood Scan
Systematic
 Resolution
 K-factor variation
 BR (BsmDsX)
 VPDL model
 BR (BsDsDs)
PRL 97 (2006)021802
17 < ms < 21 ps-1 @ 90% CL
7/21/2006
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Measurement of  and fs
• DØ has measured fs in three different processes:
– From the time dependence of polarization amplitudes
in Bs  J / 
– From time-integrated like-sign di-muon charge
asymmetry:
N ++ - N -ASL 
N ++ + N --
– From time-integrated charge asymmetry of
Bs μνDs (Ds fp ; fKK) decay:
7/21/2006
D0 Results for ICHEP
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Lifetime Difference and Mixing Phase from
BsJ/ (m+m-) f(K+K-) untagged decay
• Final state is a mixture of
CP-even and CP-odd
components;
• They produce different
angular distributions of
polarization amplitudes
A0, A|| (CP-even) and
A (CP-odd);
• Time evolution of these
amplitudes depends on
lifetime difference ΔΓ(Bs) &
CP-violation phase fs
ΔΓ(Bs )  0.17  0.09  0.03 ps -1
fs  -0.79  0.56  0.01
7/21/2006
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 vs ct
7/21/2006
D0 Results for ICHEP
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Dimuon Charged Asymmetry
• Charge asymmetry of muons from B decays
depends on the CP violation phase:
N (B  l + X ) - N (B  l - X )  
ASL 

tan(f )
+
N ( B  l X ) + N ( B  l X ) M
• Non-zero Asl corresponds to CP violation in
mixing;
• D0 has measured dimuon charge asymmetry
- better control of systematics:
N (bb  l + l + X ) - N (bb  l - l - )
A
 ASL
+ +
- N (bb  l l X ) + N (bb  l l )
7/21/2006
D0 Results for ICHEP
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Dimuon events in DØ
• ~ 5 M like-sign dimuon
events collected (1 fb-1) ;
• Excellent muon system with
very low punch-through;
• Strong suppression of
cosmic background;
• Regular reversal of magnets
polarities - reduced detector
systematics;
• Result
(Both Bd and Bs contribute) :
7/21/2006
D0 Results for ICHEP
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Asymmetry in semileptonic Bs decays
•
ASLs
can also be obtained from
time-integrated charge
asymmetry in semileptonic
decays BsμνDs:
unt
SL
A
~27K (μDs) events
N ( B s  m + Ds ) - N ( B s  m - Ds )

N ( B s  m + Ds ) + N ( B s  m - Ds )
1 x s2
1 s
s

A

ASL ;
SL
2 1 + x s2
2
x s  M s /  s   1
M(KKp)
• Large sample of decays BsμνDs
with Dsφπ was collected
s
-2
A

(
2
.
45

1
.
93

0
.
35
)

10
under different conditions SL
7/21/2006
D0 Results for ICHEP
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ΔΓs versus fs
Both DØ results on ASL can be combined
together:
– ASLd value from B-factories
Ms = 17.3 ± 0.3 ps-1 (CDF)
s tan(fs) = -0.01 ± 0.16 ps-1
7/21/2006
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 vs fs
7/21/2006
D0 Results for ICHEP
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Combining results for the Bs system
7/21/2006
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SM Higgs Production and Decays
decays
production
Search strategy:
MH < 135 GeV: associated production WH and ZH with Hbb decay
Backgrounds: top, Wbb, Zbb… complement it with WWW* and WW*
MH >135 GeV: gg H production with decay to WW*
Backgrounds: WW, DY, WZ, ZZ, tt, tW, tt
7/21/2006
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Higgs group recent results
SM
MSSM
Technicolor
7/21/2006
• H WW* (mm channel)
• H WW* (ee and em channels)
• WH  WWW*
0.9 fb -1
0.9 fb -1
0.4fb-1
• WH  mn bb
• WH  en bb
• ZH  mm bb
• ZH  ee bb
• ZH  nn bb
0.4 fb-1
0.4 fb -1
0.3 fb-1
0.4 fb-1
• Z  bb
• Z + n jets x-section
0.3 fb-1
0.3 fb-1
• hb/hbb
• bh b tt
0.9 fb-1
0.3 fb-1
• Techniparticle search using NN
• rT  W(mn) + PT
• rT  W(en) + PT
0.4 fb-1
0.4 fb-1
0.4 fb-1
D0 Results for ICHEP
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Search for H  WW*  lnln
Results based on ~ 950 pb-1 :
- ee, em channels at Moriond
- mm channel in internal review
95% C.L. limits
using CLs method
4th Generation
Model starts to be
excluded
7/21/2006
D0 Results for ICHEP
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Search for H  WW*  mnmn
7/21/2006
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Combined Higgs boson Search
14 independent channels have been combined, taking
into account correlated & uncorr. systematics
✗ WH (e) ST, DT
✗ WH (m) ST,DT
✗ WH ( l ) ST DT
✗ ZH (nn) ST,DT
✗ WWW (ee,em,mm)
✗ WW (ee,em, mm)
✗ ZH (ee, mm) will be added soon
We have used the CLs (LEP) Method
7/21/2006
D0 Results for ICHEP
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SM Higgs Combined Limit
- NNLO cross sections for HWW*
- same results as those shown at Moriond
7/21/2006
D0 Results for ICHEP
Data/SM = ~15 at 115 GeV
~ 5 at 160 GeV
32
Technicolor searches (e)
Cut-based &
Neural Network
p 110 GeV
r 210 GeV
7/21/2006
D0 Results for ICHEP
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Beyond the Standard Model
Enlarged gauge group  Z’, W’
Alternative EWSB mechanisms (TC, Little Higgs)
Relate quarks and Leptons  Leptoquarks
Supersymmetry
and includes graviton (Supergravity)
Extra dimensions
Compositeness…
7/21/2006
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New Phenomena recent results
SUSY Searches for:
Associated production of Charginos and Neutralinos eel
Associated production of Charginos and Neutralinos SS dim
0.9 fb-1
0.9 fb-1
GMSB in gamma gamma and MET
R-Parity Violating SUSY via LLE Couplings
Resonant 2nd Genereation Slepton Production
~1 fb-1
~0.4 fb-1
~0.4 fb-1
Scalar Top Pair production in Acoplanar Jet Topology
~0.3 fb-1
Non-SUSY:
0.4 fb-1
0.4 fb-1
~ 1 fb-1
~1 fb-1
Excited Muons
3rd generation leptoquarks
Randall-Sundrum gravitons
W’ en
7/21/2006
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Scalar Top in the Acoplanar Jet Topology
~
q
t1
~ 0
~
c
t1
q
scenario
c
stop NLSP and  LSP
with stc (FCNC)
~ 0
(relevant as long as m(st) < m(b)+m(W)+m())
 2 jets pT >20 (40) GeV
≥1 c-jet (soft tag) + missing ET
(optimized for various m(st),m())
Main backgrounds: W/Z+jets
Result: e.g.
Mst = 130 Gev
MΧ =50 GeV
Data: 60 evts
The highest excluded stop mass is :
Bkgd: 60±13
M ~t <131GeV for M ~0  46GeV
7/21/2006
D0 Results for ICHEP
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Charginos and Neutralinos in
Trilepton channels
•“Golden” SUSY signature but:
- low cross sections ( BR)
- soft leptons
- taus (at large tan)
 Needs large integrated luminosity
 Combine various final states
General strategy:
Two isolated (rather soft) e or m
Missing ET (n+)
+ channel-dependent cuts (e.g. anti Z, )
- An isolated third lepton or track (sensitive to t’s), or
- Two same sign leptons
Main backgrounds: DY, WW, WZ, Wg , mis-ID
7/21/2006
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Trileptons
like-sign dim
eel channel
Missing ET  pT(3)
Missing ET x pT(2)
7/21/2006
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Trileptons – combined results
Chargino mass limit of
140 GeV in the ``3l-max’’
scenario
(previous limit 116 GeV)
7/21/2006
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3rd generation leptoquark searches
2 approaches:
- double lifetime based b-tag
- m + single b-tag
 No excess of evts over SM
mLQ > 219 GeV, if B(LQnb)=1
7/21/2006
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40
Search for New Heavy Charged Gauge
Boson, W’  en
Additional gauge bosons introduced in
- Left-Right-Symmetric model
- GUT models …
Previous limit:
m W’ < 800 GeV (W’qq, D0-Run I)
Event selection:
- Isolated e ET > 30 GeV
- MET > 30 GeV
- 0.7 <ET/MET <1.3 etc
Normalization to transverse
mass spectrum in the
60 < mT < 140 GeV region
7/21/2006
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W’  en Limit
e.g. mT >150 GeV cut: 630 evts
bkg: 623±18(stat) ±79(syst)
( 573 Wen, 10 Wtn,
5 WW (Z), 24 QCD )
7/21/2006
Shape of mass spectrum + assuming:
no mixing angle,
g’=g, and
same CKM
m W’ > 965 GeV @ 95% CL
D0 Results for ICHEP
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Summary
• Steady progress in QCD/EWK/top physics
3.3s evidence for WZ production
• First results on CPV angle df in Bs system
from BsJ/ f decays and semileptonic asymmetries
• Higgs limits pushed down, factor 4-6 above SM around
MH = 160 GeV
• New limits for BSM searches: W’, SUSY, Technicolor,
3rd generation leptoquarks, …
• Several additional results in internal review for ICHEP
• THANK YOU, FERMILAB !!!
7/21/2006
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BACKUP SLIDES
7/21/2006
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Bs - an entangled system
7/21/2006
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Asymmetry  df
Previous D0 measurement:
asymmetry in like-sign dimuon production.
N ++ - N -A  ++
N + N --
A  -0.0013 0.0012(stat )  0.0008(syst)
After removing detector translates into:
ASL  -0.0044 0.0040(stat )  0.0028(syst)
Using CDF ms measurement, B-factories Asld,
fs fraction in b-fragm. one gets:
Asls = - 0.006 ± 0.009
Asls = /m tan(df)
7/21/2006
D0 Results for ICHEP
(U. Nierste: hep-ph/0406300)
46
Analysis Strategy
• Select Bs  Ds-m+X (Ds-  fp, f K+K) evnts;
• Separate Physics asymmetry A
from the detector effects by finding #s of
n ++ +
events with different muon charges (q), separately
for diff. toroid polarities () and psedorapidities (g):
8 measurements, 8 unknowns:
1
nβγ

N εβ (1 + q A)( 1 + q γ A fb )( 1 + q β A qβ )( 1 + γ A det )( 1 + q β γ A ro )( 1 + βγAβγ )
q
4
 A = Physics Asymmetry
• Find processes contributing to A
• Obtain CP violation asymmetry AsSL;
7/21/2006
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Lifetime Difference and Mixing Phase in
the Bs System
BsJ/ (m+m-) f(K+K-) untagged decay
PVV decay: 3 amplitudes, 3 decay angles
Fit the time and angular dependence for:
- decay rate difference  between
L(light) and B(heavy) B states
- mean decay rate
- allow for CP violatation df
- df = 0
mass eigenstates = CP eigentates
7/21/2006
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Time - integrated untagged decay rate
asymmetry in semileptonic Bs decays:
Bs  Ds-m+X (Ds-  fp, f K+K-)
e.g.
≈½
=½
= ½ AsSL
Experimentally:
SM predicts:
Small SM value of AsSL gives a chance to observe possible contribution
of new physics
For various extensions of SM, an enhancement of ASL can be
considerable, up to 0.5x10-2, which corresponds to sindf ~1
7/21/2006
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Bs -- M12 plane
7/21/2006
D0 Results for ICHEP
50
Top Mass in lepton+jets channel
using ideogram method
l
W+
b-jet
n
t
t
b-jet
Cuts: pt>20 GeV, MET>20 GeV,
≥4j ( pt>20, ||<2.5)
W-
jet
jet
Mjj(W)
Ideogram method:
Likelihood includes all possible assignments
of jets, and possibility of background
Lifetime-based id of b-jets when available
JES in situ calibration
7/21/2006
D0 Results for ICHEP
51
Search for New Heavy Charged Gauge
Boson, W’  en
Additional gauge bosons introduced in
- Left-Right-Symmetric model
- GUT models …
Previous limit:
m W’ < 800 GeV (W’qq, D0-Run I)
Event selection:
- Isolated e ET > 30 GeV
- MET > 30 GeV
- 0.7 <ET/MET <1.3 etc
Normalization to transverse
mass spectrum in the
60 < mT < 140 GeV region
7/21/2006
D0 Results for ICHEP
52
Lifetime Difference and Mixing Phase from
BsJ/ (m+m-) f(K+K-) untagged decay
•Final state is a mixture of
CP-even and CP-odd
components;
•They produce different
angular distributions of
polarization amplitudes A0,
A|| (CP-even) and A (CPodd);
•Time evolution of these
amplitudes depends on
lifetime difference ΔΓ(Bs) &
CP-violation phase fs
7/21/2006
D0 Results for ICHEP
53
Results from BsJ/ f
1s contours
ΔΓ(Bs )  0.17  0.09  0.03 ps -1
fs  -0.79  0.56  0.01
7/21/2006
fs = df
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Results from BsJ/ f
1s contours
ΔΓ(Bs )  0.17  0.09  0.03 ps -1
fs  -0.79  0.56  0.01
7/21/2006
fs = df
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ΔΓ versus df
• Both DØ results on ASLcan
be combined together:
– ASLd value from B-factories
Ms = 17.3 ± 0.3 ps-1 (CDF)
Combined fit 
7/21/2006
-1
+0.44
s  0.15+-00..09
ps
;
f

0
.
56
08
s
-0.41
D0 Results for ICHEP
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