NA48the CERN Kaon facility

Fixed target experiment with 400-450 GeV protons from SPS

NA48: CP violation

4εRe (14.7 2.2) 10ε

KL→ee decay A

L(14.2 ± 3.0stat ± 1.9sys)%

Ke3 Charge Asymmetry

L stat systδ (e) = (0.3317±0.0070 ±0.0072 )%

NA48: rare decays

KL→ee

1997 data (7000 events): BR(KL→ee) = (1.06±0.02stat±0.02syst±0.04norm)×10

K* = 0.207 ± 0.019 ± 0.017

In the BMS model: K* measure the relative strenght of intermediate pseudoscalar and vector meson contribution 1998-1999-2001 (600000 events)

BR(KL→eeee3.30±0.24stat±0.14syst±0.10norm)×10

KL→eeee

BR(KL→BR(KL→32.81±0.01stat±0.02syst)×10

BR(KL→) = (1.36 ±0.03stat±0.03syst±0.03norm) x 10-6

Mee

X= Mee2 / MK

2

NA48: Vus

0 2.8 9S 2.3BR(K π e e ) 5.8 (stat) 0.3(syst) 0.8(theor) 10

6 events found in the signal region with a background of 0.22+0.19-0.12

0 1.5 9S 1.2BR(K π μ μ ) 2.9 (stat) 0.2(syst) 10

NA48/1

NA48/2: cusp effect

NA48/2: “Neutral Asymmetry”

NA48/2: “Charged Asymmetry”

NA48/2: Vus

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BrsysstateKBr

)%07.001.002.046.3()( 865)0

(0

EeBrsysstatKBr

0015.02204.0|)0(|0015.02192.0|)0(|

3

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fVKfVK

us

use

V us x

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NA48/2: Ke2/K2