Wigner-cusp in Kaon Decays and Determination of Ππ Scattering Lengths
نویسنده
چکیده
In the last few years it has become possible to study low energy ππ scattering in kaon decays to three pions, thanks to the high statistics measurement of K → πππ decays performed by the NA48/2 experiment at the CERN SPS. At the ππ threshold, the ππ mass spectrum exhibits a Wigner-cusp, from which the S-wave ππ scattering lengths are extracted with high precision. This measurement is complementary to the extraction of the scattering lengths from Ke4 decays, which is also performed by the NA48/2 experiment.
منابع مشابه
Determination of the S - wave ππ scattering lengths from a study of K ± → π ± π 0 π 0 decays
We report the results from a study of the full sample of ∼ 6.031 × 10 K → πππ decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the ππ invariant mass (M00) distribution shows a cusp-like anomaly in the region around M00 = 2m+, where m+ is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge excha...
متن کاملKaon Physics: Recent Experimental Progress
The last three years have been marked by very rapid progress in experimental studies of kaon decays. This review is an attempt to summarize those results that offer direct comparison for the predictions of chiral perturbation theory (ChPT), including in particular the determination of the I = 0, 2 ππ scattering lengths from K → 3π and Ke4 data, recent results on a selection of rare and radiativ...
متن کاملK e 4 decays and Wigner cusp Contribution to the proceedings of HQL 06 , Munich , October 16 th - 20 th 2006
The single-flavour quark condensate 〈0 |qq| 0〉 is a fundamental parameter of χPT , determining the relative size of mass and momentum terms in the expansion. Since it can not be predicted theoretically, its value must be determined experimentally, e.g. by measuring the ππ scattering lengths, whose values are predicted very precisely within the framework of χPT , assuming a big quark condensate ...
متن کاملThe cusp effect in η ′ → ηππ decays
Strong final-state interactions create a pronounced cusp in η → ηππ decays. We adapt and generalize the non-relativistic effective field theory framework developed for the extraction of ππ scattering lengths from K → 3π decays to this case. The cusp effect is predicted to have an effect of more than 8% on the decay spectrum below the ππ threshold. PACS. 11.30.Rd Chiral symmetries – 13.25.Jx Dec...
متن کاملPrecision Measurement of ππ Scattering Lengths in K e 4 Decays by NA 48 / 2
Very large statistics of charged kaon decays have been accumulated in 2003-2004 by the NA48/2 experiment at the CERN SPS. The analysis of K ± → π + π − e ± ν (K e4) decays allows a model-independent approach to the study of low energy ππ scattering. From a data sample of more than 1 million K e4 decays, scattering lengths can be extracted with an improved experimental precision of few percents,...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2007