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SLIDE 1

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 1

Yen-Chu Chen

Institute of Physics, Academia Sinica, Taiwan, R.O.C. For the CDF and D0 collaboration

SLIDE 2

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 2

The mass is well measured.

– Assuming that this is really the Top/Truth!

Is it really Top/Truth of the Standard

Model (SM)?

– Studying the properties

SLIDE 3

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 3

P

P

_

t t

_

X b b

_ _ _ _

W +

+ + +

W −

− − −

l +

+ + +

q l −

− − −

q ν ν ν ν q'

_

ν ν ν ν q'

_ _

Production Cross section Top spin Rare decays, charged Higgs, etc. W helicity Top charge Top mass Charge asymmetry Life time, decay width Production mechanism FCNC Br(t→

→ → →Wb)/Br(t→ → → →Wq)

SLIDE 4

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 4

DIL

!"# #μ

μ μ μ$

%&' LJ

"# $

(

!"$

t

t W + W̅

̅ ̅ ̅

b b

e+, μ μ μ μ+, u, c e

, μ

μ μ μ–, u, c ) ) ) ν ν ν νe, ν ν ν νμ

μ μ μ , d, s

) ) ν ν ν νe, ν ν ν νμ

μ μ μ , d, s

) ) )

SLIDE 5

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 5

* +,-!

– Based on W->jj – Constraint on W boson mass

.-/00

– Use leading order matrix element – Integrating over the phase space – Find the probability density as a function of Top mass

1-22!, Lxy /-- 3-- 4!

5#6#$$

(CDF)

(CDF)

SLIDE 6

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 6

Mt = 170.9 ± ± ± ± 1.8 GeV/c^2, from 1 fb-1 CDF+D0 combination

SLIDE 7

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 7

#CDF

.33 DIL 0#2 fb-1.

– This neural networks is evolutional. – optimized on improving uncertainty.

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Moriond EWK, La Thuile, Italy 8

#CDF

mt = 177.0 ± ± ± ± 3.7 (stat+JES) ± ± ± ± 1.6 (sys) GeV/c2

# #1.9 fb-1

– Use Neural Networks for event selection. – Require b tagging. – Do In-situ jet energy calibration.

SLIDE 9

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 9

#CDF

mt = 172.7 ± ± ± ± 1.2 (stat) ± ± ± ± 1.3 (JES) ± ± ± ± 1.2 (sys) GeV/c2

/0, LJ#1.9 fb-1

– Use Neural Networks for background handling after event selection – Require b tagging – Do in-situ jet energy calibration

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Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 10

#D0

/--#DIL, 1 fb-1

– For a given mt try to resolve for Top, anti-Top momentum. – Define weight for each solution. – Account for detector resolution. – Take into account the background. – Scan through mt to reach the max. weight and the min. of likelihood.

mt = 175.2 ± ± ± ± 6.1 (stat) ± ± ± ± 3.4 (sys) GeV/c2

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Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 11

#D0

3--#DIL, 1 fb-1

– given mt and η (from MC) for each ν; resolve for ν momentum. – For each event derive weight template based on Et expected (MC) and observed. – Take into account detector resolution and background. – Define maximum likelihood, L(mtop, mean, rms). mt = 172.5 ± ± ± ± 5.8 (stat) ± ± ± ± 3.5 (sys) GeV/c2

/ / / /

mean mtop weight mtop rms mean

SLIDE 12

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 12

#D0

/0#LJ, 1 fb-1

– Use in-situ jet energy calibration. – Result without b tagging: – Result with b tagging:

e

μ μ μ μ mt = 170.5 ± ± ± ± 2.4 (stat+JES) ± ± ± ± 1.2 (sys) GeV/c2 mt = 170.5 ± ± ± ± 2.5 (stat+JES) ± ± ± ± 1.4 (sys) GeV/c2

SLIDE 13

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 13

#

SLIDE 14

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 14

#

Tevatron Top mass, 2007 Mar.

7-!89 :

CDF D0 -
$

SLIDE 15

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 15

#CDF
SM+2/3q

XM: -4/3q

Each event has lepton(s) and jets:

– Pairing : Top mass as input, Mlb

2

– Jet charge determination

The result
1.5 fb-1
:

– Exclude XM at 87% CL.

SM : t → W+ b XM: t’ → W- b

? b or b? b or b? ?

_ _

W charge × × × × jet charge

SLIDE 16

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 16

"

f0 = 0.7, longitudinal

f– = 0.3, left handed f+ = 0, right handed

SLIDE 17

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 17

" CDF

f0 = 0.65 ± ± ± ± 0.19 (stat) ± ± ± ± 0.03 (sys) f+ = -0.03 ± ± ± ± 0.07 (stat) ± ± ± ± 0.03 (sys) Fix f0 to SM: f+ = -0.04 ± ± ± ± 0.04 (stat) ± ± ± ± 0.03 (sys) f+ < 0.07 @ 95% C.L.

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Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 18

Fix f0 to SM: f+ = -0.002 ± ± ± ± 0.047 (stat) ± ± ± ± 0.047 (sys) f+ < 0.13 @ 95% C.L.

" D0

f0 = 0.425 ± ± ± ± 0.166 (stat) ± ± ± ± 0.102 (sys) f+ = 0.119 ± ± ± ± 0.090 (stat) ± ± ± ± 0.053 (sys)

LJ, Lep. LJ, Had. DIL

SLIDE 19

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 19

7b ;<t→Wb<t→Wq D0

1 7b$

– LJ , 0.9 fb-1 7b ;0.97 +0.09

0.08 (stat + sys)

> 0.79 @ 95% CL – |Vtb| > 0.89 @ 95% CL – σtt = 8.18 +0.90

– 0.84 (stat+sys)

± 0.50 (lumi) pb

SLIDE 20

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 20

1-(-- #D0

"

7;σtt&, σtt =$ =7b ;8$ 7;1.21 +0.27

– 0.26 (stat + sys)

0/$-(--

<;<t→Hb <;0.13 +0.12

0.11 (stat+sys);

< < 0.35 @ 95% CL

0.13

SLIDE 21

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 21

1FCNC CDF

1< (t→Zq) = O(10–14) <1 O(10–4) = LEP : < 13.7% @95% CL %>$&?,. @ Top, Z W. <1.9 fb-1: < 3.7% @95% CL

SLIDE 22

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 22

@

2

8$89 2: .## 1 /$

#" , 7b, -(--#FCNC

=-#

%###$

,!--2 : :

SLIDE 23

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 23

CDF 8$A

8$A 8$A 8$Afb

8

8 8 8

– 2Ln(Bayse factor) = 12.0

– f+ = SM like / Total > 0.4 @ 95% CL

W charge × × × × jet charge

probability NQ

CDF Run II preliminary L=1.5 fb-1

CDF

SLIDE 24

Mar. 1-8, 2008

Moriond EWK, La Thuile, Italy 24

#CDF

f+ measured 0.83 p value observed : 0.31