Case1 result

d&Lambda case1 correlation analysis results are presented here. Firstly, various spectyra are compared between "signal"(red) and "d on PA"(green) events.

"d from PA" events are having no structure, and considered to be BG. Hereafter, those events are eliminated from &Lambda d case1 correlation analysis.

Result without final state selection.

The reaction final states,

K- + 4He -> &Lambda + d + n

and

K- + 4He -> &Sigma0(&Lambda&gamma) + d + n

are separable by 4He(stopped K-,d&Lambda)N* missing mass MN*. Identifying the &Lambda d n final state by, 920 MeV/c2< MN* < 960 MeV/c2, and study the spectra for each of final states. Note that n+&pi0/p+&pi- as N* are energetically rejected, and hence &Sigma0 d n final state is just defined by MN* > 960 MeV/c2.

Result with final state selection. Black: all / Red: &Lambda + d + n / Green: &Sigma0 + d + n

The peak on the d&Lambda invariant mass at around 3175 MeV/c2 is found to originate from &Sigma0 final state. The presense of 1-nucleon-1-deuteron absorption,

K- + "dp"(n) -> d&Lambda(n)

and

K- + "dp"(n) -> d&Sigma0(n)

has been now experimentally verified, on the back-to-back d&Lambda energy spectrum. On the low-mass component, deuteron momentum and &Lambda momentum is extremely unbalanced.

Dalitz plot of &Lambda d n events

A Dalitz plot of a &Lambda d n final state is shown below.