DataAnalysisTech11-ch14, Study notes of Advanced Data Analysis

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第第第 第第  (^) 第第第第第第第第  (^) 第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第 第第第 第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第第 第第第 第第第第第第第第  (^) 第第第第第第第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第第

第第第 第第第第  (^) 第第第第第第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第第第第第 第第第 第第第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第  (^) 第第第第第第第第第第第第第第第第第 第第第 第第第第第第第第第  (^) 第第第第第第第第第第第第

Why Kaon ID?Why Kaon ID?

 Combinatorial background

dominated in D^0 K+^ , D()D(),

Ds  +  -

 K -  separation can reduce the

combinatorial background in

DsJ→D^0 K+^ , D^0 →K-^  +^ and  →K+^ K-

decays.

 KID efficiency and fake rate 

Cross section measurements.

Study KID with DStudy KID with D**

D*+^ → D^0 π+

└ K-π+

Trigger Sample: Two Track Trig (TTT).

TTT cut condition applied to all D^0 candidates

Track Quality required

K-K-ππ separation (dE/dx)separation (dE/dx)

Kaons

Pions

Tracks w/o dE/dx info (^)   

  ^ ^  i

f i dE dx i

dE dx K

Prob

Prob

: fraction

: , , , ,

f

i e  K  p

K-K-ππ separation (TOF)separation (TOF)

Kaons

Pions

Tracks w/o TOF info

     ^ ^  i

f i i

K

Prob TOF

Prob TOF

: fraction

: , , , ,

f

i e  K  p

Efficiency & Fake RateEfficiency & Fake Rate

Efficiency

Fake Rate

Kaon Candidates Selection: Log(ProbRatio)>

DD

00 pair puritypair purity

D^0 Invariant mass (GeV/c^2 )

Triggered D^0

~600 pb-

Extra cuts:

 Lxy(Dtrigger) > 0.

 Lxy(Dother) > 0.

 Pt(Dother)>5 GeV

 (^) Kid(Dother)>

The Other D^0

DDDD invariant massinvariant mass

ψ ψ(3770)(3770)

~600 pb-

D^0 D^0 Invariant mass (GeV/c^2 )

χ χ’’c2c2 (2(2^33 PP 22 ))

Studies of Mixing-inducedStudies of Mixing-induced CPCP

violation violation in neutralin neutral BB systemsystem

KMKM 第第第第第第第第第第第第第第第第  (^) 第第第第第第第第第第第第≠第第第第第

 Cabibbo, Kobayashi & Maskawa 第第 :

 (^) 第第第第第

第 CP 第第第第第第

 (^) CP 第第  Vij  _Vij_*^ ( 第第第第第第第第第第 )

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 

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 

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b

s

d

V V V

V V V

V V V

b

s

d

V

b

s

d

td ts tb

cd cs cb

CKM ud us^ ub

) 2

1 2

(^1 2

5 5 * W W ui Vijdj W dj Viju i L^ g ^  ^ ^  

    ^   ^ 

) 2

1 2

1 ( 2

5 5 * W W dj Vijui W ui Vijd j

g CPL    ^ ^  ^ 

      

CKMCKM 第第第第第第第第第第第第

free parameters 9 complex matrix elements (^9)  2 = 18 Unitarity of the matrix, V+V = I - 5 arbitrary phases of 6 quark field - total 4

 Wolfenstein 第第第 :

 (^) 2X2 第第  1 第第第第第第第第第第 Vij  _Vij_*

 

 

3 2

2 2

2 3

1 1

2 1 1

2 1 1     

  

     O A i A

A

A i V 

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  

 

  

complex phase  CPV

Primer onPrimer on BB mesonsmesons

 What are B mesons?

 (^) Neutral:  (^) Charged:  (^) JPC =0-+  (^) c   450  m

 How do they decay?

 (^) usually to charm: | b  c |^2 / | b  u |^2  100

 How are they produced?

 (^) e+e-^  Υ( 4S )  BB is the cleanest process

B : db , B : d b 0 0

B  : ub , B  : u b

CoherentCoherent BB

00

- – BB

00 statesstates

 Υ(4 S )  B^0 B^0 / Υ(4 S )  B + B -^  50/

 (4 S ) : 3 S bb bound state, Mass: 10.58 GeV B^0 : Mass: 5.28 GeV  B mesons created  at rest in CM  BB orbit angular momentum L =  (^) Bose statistics  B^0 B^0 state anti-symmetric

 B^0 B^0 and B^0 B^0 are prohibited  (^) At any time : one B^0 one B^0 until one B decays

  1   2   1   2   2

(^1 0 )   B B  B B