Analysis result for &Sigma case1 n 90degree

In order to eliminate the combinatorial background further, we must investigate n&pi invariant mass under various event selections.

n&pi invariant mass spectra under various event selections. Top - Black:no additional selection Red:pn_decay>200 MeV/c Green:pn_decay<200 MeV/c. Bottom - Black:no additional selection Red:pn_decay>300 MeV/c Green:pn_decay<300 MeV/c.

It has been found that the &Sigma compoent is well identified with higher momentum cut-off value for decay neutron, but the requirements for primary neutron does not change the S/N ratio. It seems to be natural, since the &Sigma detection efficiency growth with &Sigma momentum. Below, n&Sigma invariant mass spectra are presented under various event selections.

n&Sigma invariant mass spectra under various event selections. Top - Black:no additional selection Red:pn_decay>200 MeV/c Green:pn_decay<200 MeV/c. Bottom - Black:no additional selection Red:pn_decay>300 MeV/c Green:pn_decay<300 MeV/c.

Hereafter, we adopt pn_decay>200MeV/c selection.

n&Sigma invariant mass (top) and total energy (bottom) spectra classified by cos(n&Sigma).lt.-0.60(red) and ge.-0.60(green).

decay neutron (black)/&Sigma(red)/primary neutron(green) momentum spectra.

Correlation between N&Sigma invariant mass and various observables

Correlation between N&Sigma total energy and various observables