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K L → p 0 gg

K L → p 0 gg. Issues: One-loop c PT predictions expected to be accurate at 20% level give B.R. = 0.68 x 10 -6 a factor 2 smaller than the experimental results, that can be reproduced with a sizeable contribution from higher order terms.

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K L → p 0 gg

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  1. KL→p0gg Issues: One-loop cPT predictions expected to be accurate at 20% level give B.R. = 0.68 x 10-6 a factor 2 smaller than the experimental results, that can be reproduced with a sizeable contribution from higher order terms. The decay is important to understand effects beyond the one-loop approximation In particular it is interesting to measure the low-mass tails of the mgg distribution mgg < 240 MeV/c2. C.Bloise 18-Oct-04

  2. Mgg spectrum : sensitivity to cPT parameter av. Figure published by KTeV in 1999, from work by P.Heiliger and L.M.Sehgal published in 1993 (PhysRev.D47, 4920) +1 -1

  3. KTeV 1999 Phys.Rev.Lett. 83, 917 aV = -0.72±0.05±0.06

  4. F.Gabbiani and G.Valencia 2001 (hep-ph/0105006) Data: KTeV99

  5. Na48 2002 Phys.Lett. B 536, 229

  6. NA48 (2002)

  7. KTeV conclusions (1999) BR (KL→p0gg ) = (1.68±0.07±0.08)10-6 and aV = -0.72±0.05±0.06 consistent with O(p6) predictions with aV = -0.72 BR (KL→p0gg) = (1.53±0.10)10-6 BR (KL→p0ee) (CP conserving) ~ 1-2 10-12 Na48 conclusions (2002) BR (KL→p0gg ) = (1.36±0.03±0.03±0.03)10-6 and aV = -0.46±0.03±0.04 BR (KL→p0ee) (CP conserving) = (4.7±2.2) 10-13

  8. Raw m3,4 spectrum KLOE Dati 6.1 pb-1 MC 4.3 pb-1 Raw m3,4 spectrum selecting 4g events with Dp0m1,2 < 3s and Dp0m3,4 > 3s Before Kinematic fit Histos : MC Red points : Data

  9. For comparison with the other results: KLOE statistics (2.5 fb-1 ): L s(F)BR(FKLKs)Fid.Vol. BR(Ks p+p- )BR(KLp0gg)e(analysis) 2,500 3.0.34 0.3 0.6 1.5 e = 620 e

  10. KTeV 1999

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