Marianna Testa University of Rome La Sapienza & INFN for the KLOE collaboration “XLIst Rencontres de Moriond: Electroweak Interactions and Unified Theories”, La Thuile March 2006 CP/CPT tests at KLOE

2 13 e + e     b W = m  = MeV BR(  K 0 K 0 ) ~ 34% ~10 6 neutral kaon pairs per pb -1 produced in an antisymmetric quantum state with J PC = 1  Neutral kaons at a  -factory p K = 110 MeV/c S = 6 mm L = 3.5 m The detection of a kaon at large (small) times tags a K S (K L )  possibility to select a pure K S beam (unique at a  -factory, not possible at fixed target experiments) K L,S K S,L t1t1 t2t2  t=t 1 - t 2 f2f2 f1f1 

3 Kaon interferometry:   K S K L         no simultaneous decays (  t=0) in the same final state due to the destructive quantum interference I(  t) (a.u)  m  from here      t2t2 t1t1  t=t 1 -t 2

4 KLOE preliminary 380 pb -1 ’01+’02 data Fit with PDG values for  S,  L :  m = (5.34  0.34) × 10 9 hs -1 PDG `04: (5.301  0.016) × 10 9 (h/2  )s -1 Fix  m to PDG `04 value, obtain : K S(L)      at t 1  K L(S)      at t 2  S,L =   0,0 =(0.24  0.010) × Cf. Bertlmann `99(CPLEAR)  0,0 = 0.4  0.7  S,L = No simultaneous decays K L regeneration on the beam pipe K S K L interference: QM test K L,S K S,L t1t1 t2t2  t=t 1 - t 2 f2f2 f1f1   Data: 7366 evts Fit:  2 /dof = 15.1/22 ζ decoherence parameter basis dependent: K S K L, K 0 K 0 I ( Δt,  )  e −ΓL|Δt| + e −ΓS|Δt| − 2(1 − ζ S,L ) e −(ΓS + ΓL)|Δτ|/ 2 cos( ΔmΔt )      t2t2 t1t1  t=t 1 -t 2

5 BR K L      CP Violation Decay CP violating Related to  K BR mmt to 1% using K L beam tagged by K S →     328 pb -1 ’01+’02 data Selection K L vertex reconstructed in DC PID using decays kinematics Fit with MC spectra including radiative processes Normalization using K L   events in the same data set

6 Preliminary result BR(K L      )= (1.963   0.017)  in agreement with KTeV [PRD70 (2004),092006] BR=(1.975  0.012)   confirm the discrepancy (4 standard deviations) with PDG04 BR=(2.090  0.025)   PDG2004 KTeV KLOE preliminary BR(K L      )   with respect to prediction from Unitarity Triangle, using CP conserving variables  UTfit = (2.88  0.43)  Using BR(K S   ) and  L from KLOE and  S from PDG04  | = (2.216  0.013)  |  | PDG04 = (2.280  0.013)  BR K L      CP Violation (II) 1.5  with respect to prediction from Unitarity Triangle

7 Measurements of K S K L observables can be used for the CPT test from unitarity : ff (1 + i tan  SW ) [Re  i Im  ]  A*(K S  f ) A(K L  f ) SS 1   f  f      K S       00    K S            K S       kl3  S  L B(K L l3)  Re  Re y  i( Im  Im x  )   S  L B(K L l3)  (A S +A L )/4  i( Im  Im x  )     S  L     K L           S  L     K L        CPT test: the Bell-Steinberger relation

8  K S      K S       K S        K L        K L  l   K S          K L         K S          SW  = (0.759±0.001)         CPT test: inputs to the Bell-Steinberger relation  S  ± ns  L = ± 0.23ns A L   A S    K L        K L         =0.757 ±   = ± Im x + = (0.8 ± 0.7)  KLOE measurements Im x  from a combined fit of KLOE + CPLEAR data

9 We get the following results (error contours) on each term of the sum      K S       00    K S            K S       S  L B(K L l3)  A S +A L )/4  i  Im x      S  L     K L           S  L     K L        Im Re CPT test: accuracy on  i

10 Re    Im   CPLEAR: Re    Im   CPT test: KLOE result KLOE preliminary: Re  Im 