Transcript Nessun titolo diapositiva

Carmine Elvezio Pagliarone
INFN Pisa
(on behalf of the CDF Collaboration &
the t Group & Lepton+Track WG)
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
the CDFII Collaboration
CDF physicists
Canada
3%
Taiwan
3%
Germany
2%
Italy
20%
Japan
9%
4th International Workshop on VHMP, Alushta 2 June 2003
US
63%
Carmine Elvezio Pagliarone
Fermilab Tevatron Collider
D
p source
Main Injector
and Recycler
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
The Fermilab Accelerator Complex
• Main Injector (150 GeV proton
storage ring) replaces Main Ring
(the original accelerator);
• Completely revamped stochastic
cooling system for antiprotons;
• A new permanent magnet Recycler
storage ring for antiprotons;
• Increased number of p and p-bar
bunches :
6  36 (396 ns)
• Higher center of mass energy
2 TeV achived increasing the
beam Energies
900  980 GeV
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Tevatron Collider Improvements
L=
N
Npp
3 r f 0

N
N
BN
B
p
p
*
 p



Total Antiprotons


 F  * , x , y ,  p ,  p ,  z



1  p  p
(
)
p per bunch
Physics Opportunites
•
•
•
•
•
•

Top
Higgs
QCD
Electroweak
B Physics
New Phenomena
4th International Workshop on VHMP, Alushta 2 June 2003
?
?
?
?
Carmine Elvezio Pagliarone
Tevatron Run I History
Discovered: Top, Bc, diffractive…
Measured: MW, Mtop, tt, sin2, …
Ltot= 110 pb-1
s 1.8TeV
~ 1 yr to get x 10
Steady progress after that…
Run 1A
(1992-1993)
Run 1B
(1994-1996)
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Tevatron Performances vs Expected Luminosity
s  2TeV
2 x 1032
cm-2 s-1
2 fb-1
2000
4th International Workshop on VHMP, Alushta 2 June 2003
2002
2004
5 x 1032
cm-2 s-1
15 fb-1
2006
2008
Carmine Elvezio Pagliarone
Present Tevatron Luminosity Performance
4.7●1031
Tevatron Peak Luminosity
peak luminosity
average luminosity
integrateed luminosity
Tevatron Integrated Luminosity
240 pb-1
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Present CDF/D0 Luminosity Status
240 pb-1
Delivered Luminosity
Physics Luminosity
CDF
D0
180 pb-1
130 pb-1 (since April 02)
CDF Integrated Luminosity
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Short term Luminosity Prospects
– Massive effort put into understanding and improving
Luminosity
• Fixed Accumulator  MI optics
• Much work on stabilizing tunes in injection and low beta
squeeze
• Fight large antiproton emittances
• Work on accumulator lattice to reduce beam heating
– Max luminosity achievable without Recycler ~8x1031
– Need recycler to get to 2 x 1032
• full benefits of Recycler later on
Peak Luminosity: 4.7●1031
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Long term Luminosity Profile
previous estimate
by Year 2009
(5.5  9.5 fb-1)
(4.5  5.5 fb-1)
without electron cooling in
the Recycler
with electron cooling in the
Recycler
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Si tracking
CMX
IMU


Endplug Calorimeter
Tracking











Layer 00
SVX II
ISL
COT
Front End Electronics
Trigger (pipelined)
DAQ System
Muon Systems
Luminosity Monitors
TOF
Offline Software
CMX Mini skirt
4th International Workshop on VHMP, Alushta 2 June 2003
COT
CMP
Carmine Elvezio Pagliarone
The CDFII Tracking System
•
Central Outer Tracker (COT):
– open cell drift chamber
– maximum drift time 100ns
• Small cell size, Fast gas
– single hit resolution ~200 mm
– excellent pattern recognition
– improved stereo capabilities
•
•
Silicon Tracker System:
–
–
–
–
COT into CDFII
increased z coverage (length ~ 1m)
 coverage up to |  | < 2
3-D track reconstruction
impact parameter resolution
•  < 30 mm
• z < 60 mm
3 different detectors: ≈750,000 channels
–
–
–
L00: inner most, R= 2.5 cm, rad-hard, SS
SVXII: 5 layers, 3<R<10 cm, DS (90 and sas)
ISL: 2 layers, 10<R<20 cm and large , DS
4th International Workshop on VHMP, Alushta 2 June 2003
Trigger System: two main
improvements
•XFT: Track reconstruction at L1
•SVT: Displaced track triggering at L2
Carmine Elvezio Pagliarone
CDF II Silicon
Detectors
CDF
Layers
Length
Channels
Modules
Readout Length
Inner Radi us
Outer Radius
Power
Layer 00
1
0.9 m
13824
48 SS
14.8 cm
1.35 cm
1.65 cm
~100 W
SVX II
5
0.9 m
405504
360 DS
14.5 cm
2.5 cm
10.6 cm
1.4 kW
4th International Workshop on VHMP, Alushta 2 June 2003
ISL
2
1.9 m
303104
296 DS
21.5 cm
20 cm
28 cm
1.0 kW
Totals
8
722432
704
1.35 cm
28 cm
2.5 kW
Carmine Elvezio Pagliarone
CDF II Layer 0
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
SVX II Detector
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
ISL
•ISL provides one space point to improve
track matching between SVX II & COT.
•Total Length  2 m;
•1 central layer covering||<1 (r= 20 cm)
•2 layers covering 1<||< 2 (r= 20&28 cm)
• PT/P2T=9·10-4(GeV/c)-1
for (||<1,PT=10GeV/c)
•In the forward region ISL&SVXII
constitue a standalone 3D silicon tracker
with up to 7 axial + 7 stereo measurements
out to ||  2
•Carbon fiber structure:
Max. rigidity & min. material
•Beryllium support for ladders
•6th layer: 28 ladd/barrel
•7th layer: 36 ladd/barrel.
3 Double side p-n
sensors axial+stereo (1.2º)
4 SVX3 Chips on each side
The hybrid is placed at the
end of the ladder
Ladder length ~ 25 cm
4th International Workshop on VHMP, Alushta 2 June 2003
top anti top Event
Carmine Elvezio Pagliarone
Central Outer Tracker
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
CMX
IMU
Muon System
CMX Mini
skirt
CMU
CMP
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
TOF System Performance
TOF + track informations
Cut on TOF info
•
•
110 ps of average resolution
(from preliminary calibration)
Getting close to 100 ps goal;
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
CDF Trigger system
Level 1
storage
Level 1
pipeline:
42 clock
cycles
L1
Accept
Level 1
 7.6 MHz
Synchronous Pipeline
 5544 ns Latency
 50 KHz max Rate
Level 2
L2
Accept
L3 Farm
› 150 Triggers
3 step Trigger System
• Tracks available at Level 1
eXtremely Fast Tracker (XFT)
Level 2
• Asynchronous 2 Stage Pipeline
• 20 ms Latency
• 300 Hz Accepted Rate
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
CDF-II Status
•
Detector:
– All systems were installed and commissioned by end of 2001;
•
DAQ and trigger:
– Running physics trigger table with > 150 trigger paths since Feb ‘02
• New SVT very successful
– Typical running conditions:
• L1: 3.5KHz
•
L2: 200 Hz
L3: 20 Hz
Data processing:
– Reconstruction farm keeps up with data logging
– Physics groups skim data:
• Observe signals from low and high PT triggers: J/y, D, B, W, Z
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Run II detector improvements
• Improved z coverage of Silicon tracker 
+50% of Run I geometrical acceptance (…top)
• 3D vertexing capabilities 
better fake rejection
• Track reconstruction can be extended to
1<<2  several major effects:
– b-tagging (recover ~30% of b’s in tt events)
– lepton ID (electrons in Plug calorimeter)
• Increased muon system acceptance by 12% 
affects trigger, ID and SLT efficiency
Efficiencies
Run I
Run II
SVX (b-jets)
44 %
65 %
SLT (b-jets)
13 %
13 %
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
t Physics at CDFII
INFN Pisa, UC Davis, LPNHE Paris,
Rutgers, Texas A&M, Waseda U.
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
t Decays and t signatures
 t decay promptly either to leptons or to hadrons;
 always 1 or 2 n in the final state;
 Leptonic t decays BR= 35.2%;
 Hadronic t decays BR= 64.0%;
(40.7% 1-prong, 23.3% 3-prongs)
 Leptonic t-decays are difficult to identify:
 small impact parameter: ct= 90mm;
 low-pT isolated leptons (30% of parent pT);
 Hadronic t-decays have a distinct signatures:
 narrow isolated jet (no m or e);
 low track multiplicity (1 or 3);
 M(visible decay product)<Mt ;
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Taus in Run II
•
•
•
•
Many searches with taus in the final state;
Taus were traditionally more “difficult” for both experiments;
Needs of a significant improvement;
CDF Lepton+Track (LT) WG designed and implemented
single tau and Ditau Triggers (5):
– t + MET,
– th + tl (l= e, m)
– th th
• lepton+Track Trigger
– Lepton PT> 8 GeV/c;
central-e, central-m, forward-m;
– Tau-style isolated 5 GeV/c track;
– Targets multilepton final states including
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
CDF-II Tau Triggers
5 Tau Triggers
1. Central m + Track
2. Forward m + Track
tln
3. Electron + Track
4. Di-t Trigger
t  hadrons
5. t + ET
In the Trigger Table since Jan 2002
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Lepton+Track Trigger
pTseed> 5 GeV/c
Tau Cone
t
Isolation Cone
•Lepton (e,m)
Lower PT Threshold
Z
•Isolated track
No tracks in 10-300 Cone
t
pTl > 8 GeV/c
4th International Workshop on VHMP, Alushta 2 June 2003
No prescale with
high luminosity !!
Carmine Elvezio Pagliarone
Offline Tau Cone definition (the new approach)

= max[min(0.2 rad,(5 GeV∙rad)/E_tau_vis),0.005 rad]
 largest separation Angle between
the shoulder and the seed traks
Visible Energy
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Tau ID Cuts (new approach)
• TauFinderModule
reconstruction parameters
•Seed tower ET > 6 GeV
•Shoulder tower ET > 1 GeV
•Ntowers <= 6
•|Cluster detector eta| < 1.1
•Seed track pT > 4.5 GeV/c
•
ID cuts
•tau cone: (t)= max[min (0.2 rad, (5 GeV∙rad)/E_tau), 0.005 rad]
•No tracks, no p0 in the isolation annulus:
(t) <  < 0.5
•Calorimeter isolation Iso0.4 < 3 GeV
•|Seed track Z0| < 60 cm
•Anti electron: xi_e = E_HAD/SUM (P) < 0.15
•Anti muon: CMU/P/X stubs in 15 degree cone = 0
•Mass (tracks + p0s) < 1.8 GeV/c**2
•Calo Mass < 5 GeV/c**2
•Extra cuts (still under study)
•Cluster width (eta and/or phi)
•Number of p0 in cone / isolation annulus
•Track(s) impact parameter
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
t Physics at CDFII
several analysis underway
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Z Event Selection
• Baseline selection: e+th
e: 10 GeV, th : 20GeV
• Transverse mass cut to reduce
W+jets events:
MT(l,ET) < 25 GeV/c2
• Vector Sum pT cut to reduce QCD
events
pT(l,ET) > 25 GeV/c
• Example: Run I
(e: 10GeV, th :15GeV)
(OS l th + 0 jets)
4th International Workshop on VHMP, Alushta 2 June 2003
CDF Run I Preliminary
Carmine Elvezio Pagliarone
W/Z  t t- track Multiplicity
After Baseline( e /th ), MT, PT cuts
Data: 78 Events
• Zteth (fit): 46 ± 15 events
• QCD (fit): 28 ± 14 events
• Zee (fit): 3.7 events
4th International Workshop on VHMP, Alushta 2 June 2003
Data: 2345 Events
Compare (W)*BR(W->t n)
to
(W)*BR(W->e n)
gt / ge = 0.99 + 0.04
Carmine Elvezio Pagliarone
Z  t tAfter Baseline(e /th ), MT, pT cuts, OS
Mass (OS data)
Data : 47 events
• Zteth (fix): 39 evts
• QCD (fit): 11±6 evts
• Zee (fix): 2.8 evts
Finalizing Z analysis, including the m m- channel
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
RPV mSUGRA Search in Decays of Stop Pair
•
•
Stop pairs are produced thru RPC
Assuming RPV only in the 3rd
generation( '333 in 'ijk LiQ j D k ):
th selection (106 pb-1):
~~ ~
pp  t1 t1 , ( t1  bt )
– th: cluster PT>15 GeV/c, ||<1.0
th ID: number of tracks and po
in a narrow cone, isolation
energy, etc.
 (bln ln t )(b t h )
~
t
_
~
b t
t
t
l + th + b + b
b
Trigger
No b-tag for Run I
Dominant SM BGs
•Z(tt) + >2 jets
•W(ln) + >3 jets
•QCD
_
•t t  Wb+Wb
•WW/WZ/ZZ
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Additional Selections:
MT(lepton,ET)< 35 GeV/c2 HT(lepton,th,ET)> 70 GeV
 2 jets: ET > 15 GeV
channel
Background
Events
e
1.92  0.18
0
m
1.13  0.13
0
4th International Workshop on VHMP, Alushta 2 June 2003
ALEPH Limit: m~t  93 GeV/c 2
Carmine Elvezio Pagliarone
Run II Preliminary Results
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
2TeV
 limit1  1  L1   limit 2   2  L2
 limit 2 1  L1


 limit1  2  L2
1.0
110 pb -1


-1
1.0 - (0.5  0.5) 2 fb
1
Mass Limit :

122  188 GeV/c2
14
Assuming same efficiency, same background level
due to 1 b-tag, naturally not observing the process
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Top quark Production
Pair production
4th International Workshop on VHMP, Alushta 2 June 2003
Single top production
Carmine Elvezio Pagliarone
Br  Br (t  ~t1  LSP)
SM-SM top decay
t t  bb W W -
qq bqq b
qq b n  b
n b 'n 'b

 n  b n  b
4th International Workshop on VHMP, Alushta 2 June 2003
31 / 811- Br 2
12 / 811- Br 2
2 / 811- Br 
2
1 / 811- Br 
2
Carmine Elvezio Pagliarone
Light stop: the theoretical prejudices
Becouse of Yukawa the scalar top squark can be light
But there are also arguments that directly favor this !
EWK Baryogenesis: generate the observed baryon number of
the Universe at the EWK phase
transition 119  M ~  172 90  M ~  M
t1
t1
t
!
J. M. Cline, hep-ph/9810267
M. Carena et al., Nucl.Phys. B524 (1998)
D. Delepine et al., Phys.Lett. B386 (1996)
LSP is a good candidate for Dark Matter; to get the right relic
LSP density  for 0.1 LSP  0.2 we only need: M ~t - M LSP  11, 33 GeV / c 2


~
~
t1  tR , Br t  t1  LSP  40 50 %
1
J. Wells & G. Kane, hep-ph/9810267
M. Hosch et al., Phys.Rev.D58 (1998)
G. Malone et al., Phys.Rev.D55 (1997)
J. Sender, Phys.Rev.D54 (1996)
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
SUSY decays of the top
e-e
(1/81)xB
mu-mu (1/81)
tau-tau (1/81)
SM-SUSY top decay
x 2Br(1-Br)
e -mu (2/81)
Br  Br (t  ~t1  LSP)
e -tau (2/81)
mu-tau (2/81)
e+jets (12/81)
t t  bW ~t1  LSP  bWb~1  LSP
31 / 812Br 1- Br 
qq bn b  2LSP 12 / 812Br 1- Br 
n b 'n 'b  2LSP 2 / 812Br 1- Br 
qq bqq b  2LSP

n bn b  2LSP
mu+jets(12/81)
tau+jets(12/81)
jets
(36/81)
1 / 812Br 1- Br 
e-e
(1/81)xB
mu-mu (1/81)
tau-tau (1/81)
SUSY-SUSY top decay
x Br2
e -mu (2/81)
e -tau (2/81)
mu-tau (2/81)
t t  ~t1 ~t1 2LSP  b~1b~1 2LSP
qq bqq b  4LSP
31 / 81 Br
2
mu+jets(12/81)
qq bn b  4LSP 12 / 81 Br
n b 'n 'b  4LSP 2 / 81 Br 2

2
n bn b  4LSP 1 / 81 Br
2
4th International Workshop on VHMP, Alushta 2 June 2003
e+jets (12/81)
tau+jets(12/81)
jets
(36/81)
Carmine Elvezio Pagliarone
SM top decay
(Lepton+jets)
SM-SUSY top decay
(Lepton+jets)
SUSY-SUSY top decay
(Lepton+jets)
LSP
~t
1
LSP
1
1
~t
1
LSP
LSP
LSP
LSP
~t
1
1
LSP
LSP
1
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
SUSY Parameter Space
 The tt decay can be defined in terms
of 5 parameters:
M ~t
M
1
1
M LSP
~
BR(t t1  LSP)
BR(1 n LSP)
 Assuming that only SM and SUSY top
decays are allowed then:
M LSP
~
BR(t  bW ) 1- BR(t  t1  LSP)
 the BR for the chargino leptonic decay is
almost the same in any model:
BR(1 n LSP)
1
 1/ 9
 So we end up with a general SUSY phase
space:
M ~t M
1
M ~
1
This is a Model
independent Search !
~
BR(t t1  LSP)
M LSP
1
SUSY Space
to explore
M ~t
?
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Model Assumptions
~
t j  c~i0
b~i
t~i0
tg~
~
~
~t 
Z ~t1
h~t1
W b H b
j
~t  W b 0 H b 0 ...
j
1
1
• In General SUSY Models:


 1
Br 1  n  LSP  0, 
 3
• When all the squarks and slepton masses
get heavy:


Br 1  n  LSP 
1
9
• As we are not assuming any GUT Scale
Unification:
M LSP 
1
M
2 ~1
• In most of the models we have:


~
Br t1  b11  100%
for
4th
M ~t  M ~ 
1
1
International Workshop on VHMP, Alushta 2 June 2003


~
Br t1  b11  100%
Carmine Elvezio Pagliarone
Top Kinematic
Analysis Cuts
pT (m ) 20 GeV / c, ET (e) 20 GeV
pT (m ) 20 GeV / c, ET (e) 20 GeV
E T  25 GeV
E T  25 GeV
M T  40 GeV / c 2
M T  40 GeV / c 2
2
2
Analysis Path
R   2   2  0.4
R   2   2  0.4
ETjet (1) 20 GeV / c 2
ETjet (1) 20 GeV / c 2
 W+ 3 Jets Analysis
 Reduce as much as
possible QCD BKG
ETjet (2) 20 GeV / c 2
ETjet (2) 20 GeV / c 2
ETjet (3) 20 GeV / c 2
ETjet (3)  15 GeV / c2
cos(i* )  0.7
cos(i* )  0.9
cos( *j )  0.7
cos( *j )  0.8
cos(k* )  0.7
cos(k* )  0.7
R jet (1,2,3) 0.7
R jet (1,2,3)  0.9
 Kinematic Cuts
 b-tag (SECVTX)
 Discriminate
between SM & SMSUSY
 Excluded Br without
taking in account
QCD
1
2
3
R jet  min R( jeti , jet j )i, j 1,2,3(i  j )
R( jeti , jet j )  2   2
pT (W ) Alushta
Momentum
E T -Transverse
4th International Workshop on VHMP,
2 June 2003
1
2
3
PT (W )  50 GeV / c
E T  45 GeV
SECVTX Tag
ln RL  discri min ation
Carmine Elvezio Pagliarone
95 % CL Limit
 Result interpreted in general SUSY Model assuming
R-Parity conservation;
 Model independent search
 no GUT Scale unification
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Run II SM Higgs Sensitivities
maybe
forget the discovery
?
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
another Lep+Track signature
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Why H mt ?
• strong evidence in favour of netrino masses and mixing;
• Higgs sector is the last constrained;
• LFV effects on Higgs sector parametrized
as function of the flavor changing coupling parameter: Kij
• Surprisingly we don’t have limits on the size of the LFV in
the Higgs sector !
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Motivations
 Separate conservation of the Family Lepton Number (Le,Lm,Lt)
follow directly the fermion quantum number assignment assumed
in the SM;
 There are many extensions of SM in which Lepton number can be
violated;
 The Severe experimental limits on the existence of FCNC place
stringent constraints on the FC sector of extended Models;
 LFV may anyhow appear at tree level or induced at higher
orders;
 Higgs sector is the last constrained in theory beyond the SM
possible Discovery Channel;
!
Findout whether some remnant effect of LFV
show up in Higgs decay;
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Models with LFV
LFV can arise in several Theoretical Models:
 Effective Lagrangian Approach;
 SM with massive neutrinos;
 Two Higgs Doublet Model (THDM): THDM-I, THDM-II, THDM-III;
 Models I and II solve FCNC problems by requiring a discrete
symmetry that restrict each fermion to couple at most to one Higgs
doublet;
 Models III: flavor changing neutral scalar interaction suppressed to
acceptable level by imposing a realistic pattern to Yukawa
matrices;
 E6 Unification Models;
 MSSM: LFV arise at 1-loop in the Minimal SUSY extension of SM;
 SUSY with right-handed Majorana Neutrino;
 SUSY with R-parity Violation
 See-Saw;
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
LFV in the Higgs Sector
 Within the Higgs mass-eigenstate basis, LFV interactions for a
light neutral Higgs boson can be written as:
LLFV ij cos i  j h0  h.c.

Mixing Angle of the
Neutral Higgs sector
ij
Yukawa couplings
ij
dimensionless model
parameters
n=
246 GeV
 to satisfy the FCNC Data the Yukawa couplings can be taken as:
Cheng & Sher
ansatz
mi m j
ij  ij
v
 The neutral Higgs LFV decay width is then:
h   
0
 i j

ij2

cos2  mH
8p
 with different assumptions: Br(h0  mt)  [0.1-0.01]
(reachable @future Experiments !)
 the other LFV decay channel is unreachable:
Br(h0  em)  [10-5-10-6]
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Two Higgs Doublet Model (THDM-III)
Br(h0  mt) and Br(h0  em) have been estimated also in
THDM-III:
mh0
(GeV)
Br(h0  mt)
sin = 0.1
Br(h0  mt)
sin = 0.9
Br(h0  em)
Br(h0  em)
sin = 0.1
sin = 0.9
100
0.7
0.1
1.3 x 10-5
2.0 x 10-6
130
0.7
0.1
1.2 x 10-5
2.1 x 10-6
170
0.3
1.2 x 10-3
5.5 x 10-6
2.3 x 10-8
200
0.1
3.5 x 10-4
2.2 x 10-6
6.4 x 10-9
(Cotti, Diaz-Cruz, Pagliarone, Vataga hep-ph/0111236)
the focus can only be on the channel:
h0  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
E6-inspired Unification Models
Multi-Higgs SUSY Models are particularly motivated in E6
unification models where a Higgs pair can be associated with
each family;
mA (GeV)
z1 sin 1 Br(h0  mt)
x10-3
htm
100
0.5
0.3
(0.2,0.01,0.002)
(0.86,0.77,0.75)
150
300
100
150
300
0.5
0.3
(0.99,0.91,0.85)
0.5
0.3
-0.8
0.3
-0.8
0.3
-0.8
0.3
(1.0,0.6,0.4)
(3.0,2.5,2.0)
(2.0,0.1,0.03)
(20.,15.,12.)
(42.,40.,38.)
(0.95,0.85,0.82)
(0.40,0.20,0.20)
(0.84,0.98,0.99)
(0.96,0.99,0.99)
tan = (5,20,50)
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
A Model Independent Approach
 Explore the largest number of LFV theoretical scenarios;
 LFV effects on Higgs sector parametrized as function of the flavor
changing coupling parameter: Kij;
 Kij will account for the overall theoretical dependence;
 Higgs sector then can be parametrized by Kij so that the flavor
mixing structure due to the Higgs coupling is at tree level:

2
ij
mi m j
v
h0 i j
 the corresponding decay width for h0  mt is:
h 0  mt    mt2 mH
mm mt
4pv 2
 the ratio between the two processes h0  mt and h0  tt is:
h0  mt 
2 mm

2

mt
h0  tt 
mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Production Cross Section (III)
h0  mt
HDECAY
 s M Z2  
0.120 0.003
mc M c   1.22  0.06GeV / c 2

HIGLU
mb M b   4.22  0.05GeV / c 2
Mt

174 5 GeV / c 2
not forbidden yet !
Comparable with H tt
H  mt    mt2 mH
mm mt
4pv 2
H  mt 
2 mm
 2 mt
H  tt 
mt
  pp  H  mt ; mH    pp  H ; mH   BR( H tt ; mH )  F (  mt , mH )
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
about Kij (ij)
- Kij is a product of the Model Parameter ij and the neutral Higgs
Mixing cos(;
LLFV ij cos i  j h0  h.c.
- ij, cos( are free parameters;
ij  ij
mi m j
v
- without a priori knowledge of a more fundamental theory is
usual to consider from a model-buildining point of view:
ij=1, cos( 1
- the strongest bound on the ij parameters arise from the
muon anomalous magnetic moment:
mt  10
Other interesting bounds are obtained from m  e  :
em mt  5
Other Low Energy Probes are not expected to be
sensitive enough to reach the natural size mt ~ O(1);
LFV Higgs decay mode are then relevant even if we don’t
find a LFV Higgs decay !
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Signature & Backgrounds
 2 flavor-changing charged leptons:
high-PT m + MET + t-jet
 no much hadronic activity;
 Only t  Hadrons;
 Veto extra jet-activity:
 th identified using CdfTau object;
 Backgrounds:
pp W   jets  m n m  jets Jet missidentified as a t-jet
pp  Z ( * ) t t   m n mntt had
pp W W -  m n mt had
nt
pp  WW t hadnt t ( mn mnt )nt
pp  tt  m n m bt nt b
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
A quite spectacular signature…
m
i. The t lepton from the signal is ultrarelativistic
Missing-ET from t is collinear with the t-jet:
 ( E T , pTt - jet )  0
t
n
-cos(mn)= 1
ii. As a result of two body decay
Large azimuthal opening angle between the m and the t-jet:
 ( pTm , pTt - jet )  p
iii. As side effect of two body decay, because m is monoenergetic and
t goes in more final state particles…
m will appear harder than the t-jet:
PT ( pTm , pTt - jet )  ( pTm - pTt - jet )  0
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
… but the highest Signal Acceptance is needed
PT(trk)> 5 GeV
ET
@CDF m is a MIP
uncorr
t
4th International Workshop on VHMP, Alushta 2 June 2003
m
Carmine Elvezio Pagliarone
Muon PT
MH/2
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
PT(m,t)
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Missing Transverse ET
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
(m,t)
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
(m,ET)
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Higgs Transverse and Invariant Mass Reconstruction
The effective transverse mass of the tm system is:
MT 
pTm pTt - jet [1 - cos  ( pTm , pTt - jet )]
MT for the signal is expect to peak toward the Higgs mass;
Backgrounds: because the final states may contain several neutrinos,
would peak at lower values;
Invariant Mass Recon: The 4-momentum of t lepton is reconstructed
from the t-jet and the missing transverse momentum as follow:



pTt  pTt - jet  pTmiss
t
t - jet
pz  pz

( E t ) 2  pt

pTmiss 
1  t - jet 
pT 

2
2
mmt
 ( pt  p m ) ( pt  p m )
 (mt ) 2
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Invariant Mass MH(m,t) method I
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Invariant Mass MH(m,t) method II
pp  W (  mn m )  Jets pp  Z ( * ) t t -  mn mtnt pp WW  -n n  pp H  mt
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Bound on LFV couplings Kmt
(Cotti, Diaz-Cruz, Pagliarone, Vataga hep-ph/0111236)
Kmt
95% C.L.
Tevatron (4 fb-1)
LHC
(100 fb-1)
VLHC
(1000 fb-1)
mh0
Experimental Analysis is under way
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone
Motivations
PT(trk)> 5 GeV
 Strong evidence in favor of LFV from
neutrino experiments;
 Present experimental bounds severly
constraint most hypothetical sources of LFV;
 Flavor-mediation possible in the Higgs
sector with important BR∙;
Surprisily we don’t have limits on the size of
the LFV in the Higgs sector !
t
m
Kmt
Discover o not, Tevatron can provide
important information on the flavor structure
mh0
4th International Workshop on VHMP, Alushta 2 June 2003
Carmine Elvezio Pagliarone