Today's Progress 26. May. 2006 (updated every moment)

(stop K^+,X) spectrum by PA-PB

Here, we check how the new PA-PB TOF analysis works.

  • 1. Target fiducial volume selection
  • 2. Stopped K selection with vertexz-vs-deltaE_T0
    • are applied. Other selection is not applied at all for the all spectra exhibitted below. All slewing correction has been applied as described previously.

    Arm-by-arm 1/beta spectra and correlations between 1/beta and PA/PB-detected ADC pulse heights.

    beta-inverse spectrum from stop K^+ events. beta-inverse VS energy on PB (local). beta-inverse VS energy on PB (global). beta-inverse VS energy (sqrt((ADC-P)u*(ADC-P)d) on PA.

    Correlations between 1/beta and y/z positions on PA and PB for e/mu/pi peaks.

    beta-inverse VS y on PA beta-inverse VS z on PA beta-inverse VS y on PB beta-inverse VS z on PB

    Correlations between 1/beta and y/z direction cos detected by PDC for e/mu/pi peaks.

    beta-inverse VS y on PA beta-inverse VS z on PA

    Correlations between 1/beta Energy on PB/Total energy (PB+NT).

    beta-inverse VS energy on PB beta-inverse VS total energy

    PA-PB TOF momentum spectra from (stopped K^+,pi) decay. All TOF parameters are adopted from mu^+ result without any modification. Note that 4He events and stopped events are properly selected by means of vertex z VS T0 energy, and z and y hit positions on PB are limitted to be -500 ~ + 500 mm, to avoid possible additional bump structure due to PID. pion momentum from stop K^+ decay determined by PA/PB for run 136-141. pion momentum from stop K^+ decay determined by PA/PB for run 136-141. pion momentum from stop K^+ decay determined by PA/PB for run 136-141.

    DCA distribution for e(0.96 < 1/beta <1.04, black ), mu (1.06< 1/beta < 1.14 red) and pi (1.185 < 1/beta < 1.265 green) and slow pi (1/beta > 1.3, magenta). The DCA is extremely narrow for Kmu2 events, while relatively broad for 3-body decay-products.

    DCA distributions