A Search for Direct CP Violation in $$K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp}$$ Decays
- Univ. of California, Berkeley, CA (United States)
An experimental search for CP violation in $$K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp}$$ decays has been performed in Experiment 871 at the Fermi National Accelerator Laboratory. The experiment used an 800 GeV/c primary proton beam impinging on copper targets to produce charged Kaons which were then collimated through a curved channel in a magnetic field. The three pions from the Kaon decays were tracked in the spectrometer with four high-rate multiwire proportional chambers upstream of an analysis magnet and four more downstream. The data was collected between April 1997 and September 1997, resulting in 43.3 billion positive and 18.8 billion negative Kaon triggers. Based on 41.8 million $$\tau^+$$ decays and 12.4 million $$\tau^-$$ decays of charged Kaon, the linear slope parameter $$g$$ describing the energy spectrum of the odd pion in the expansion of the squared matrix element was estimated using a Hybrid Monte Carlo method. This is the largest sample of $$\tau$$ decays of charged Kaons ever analyzed, over an order of magnitude larger than the previous analysis. The asymmetry in the linear slope $$g$$ was found to be $$\frac{\Delta g}{2g_{PDG}}$$ = [2.2 $$\pm$$ 1.5(stat) $$\pm$$ 3.7(syst)] x $$10^{-3}$$ This result is consistent with no CP violation in $$K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp}$$ decays.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1371865
- Report Number(s):
- FERMILAB-THESIS-2000-35; LBNL-47014; LBL-47014; UMI-30-02621-MC; 543818
- Country of Publication:
- United States
- Language:
- English
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