Today's Progress 19. June. 2007

p&Sigma-/n&Sigma correlation analysis

Final form of topology-by-topology n&pi invariant mass spectra.

Case1 p 180degree (top panel) and Case1 p 90degree (bottom panel). On both, the black is constructed under 300MeV/c>p&pi>135 MeV/c. The red is the subsets of the black fulfills the requirents for decay particles. The green is the one constructed from the complement.
Case1 n 180degree (top panel) and Case1 n 90degree (bottom panel). On both, the black is constructed under 300MeV/c>p&pi>135 MeV/c. The red is the subsets of the black fulfills the requirents for decay particles. The green is the one constructed from the complement.
Case2 p 90degree (top panel) and Case2 p 180degree (bottom panel).
Case2 n 90degree (top panel) and Case2 n 180degree (bottom panel).
Case3 p 90degree (top panel) and Case3 n 90degree (bottom panel).

N&Sigma correlation analysis

Here we perform p&Sigma-/n&Sigma correlation analysis with E549+E570 full statistics.

E549/570 cycle-by-cycle &Sigma N event statistics. For the primary neutron, selection A means the neutron detection software threshold (3~5 MeVee) and 1/&beta selection (1.6-7.0~9.0) to define physical neutron. For the primary proton, it is defined by successfull energy loss correction with 'reaction vertex' and layer B hit if the proton is measured on TC. Selection B is defined by the elimination of unhealthy PB counter hit(nothing for 1st cycle, R-15 for 2nd second cycle).
YN pair(dibaryon/tribaryon channel) case ID(Selection) Angler acceptance PA/PB/NT particle TC particle No. of reconstructed &Sigma No. of event after ANo. of event after B (yield of &Sigma N pair with well-defined momenta)
&Sigma-p(X0/S0) 1(C-b-1-x/A-b-3-x) 180+-30n+p&pi 1617/1639/654 1569/1581/632 1487+1581+620=3688
&Sigma-p(X0/S0) 1(C-b-x-1') 90+-45n&pi+p2179/2208/1071 1544/1620/752 1544+1620+752=3916
&Sigma+-n(X+/S+)1(C-b-3-x) 180+-30n+n&pi1562/1584/715 992/1017/457 992+1017+457=2466
&Sigma+-n(X+/S+)1(C-b-x-3') 90+-45n&pi+n1189/1152/537 1189/1152/537 1189+1152+537=2878
&Sigma-p(X0/S0) 2(B-c-1-x) 90+-45&pi+pn272/296/127 258/280/119 232+280+110=622
&Sigma-p(X0/S0) 2(B-c-x-1'/B-a-x-3')180+-45&pin+p 1676/1759/689 1467/1535/602 1387+1535+586=3508
&Sigma+-n(X+/S+)2(B-c-3-x) 90+-45&pi+nn 426/484/168 426/484/168 406+484+164=1054
&Sigma+-n(X+/S+)2(B-c-x-3')180+-45&pin+n 515/485/189 515/485/189 487+485+185=1157
&Sigma-p(X0/S0) 3(B-a-3-x) 90+-45&pi+np 991/1063/415 695/723/291 657+723+281=1661
&Sigma+-n(X+/S+)3(B-c-3-x) 90+-45&pi+nn 1379/1368/517 1379/1368/517 1305+1368+509=3182

The definition of variables are as follows:

&Sigma 4-momentum p&Sigma(0:3)/3-momentum p'&Sigma(3):p'&Sigma(i)=pp(i)+p&pi(i), p&Sigma(i)=p'&Sigma(i) (i=1,2,3), p&Sigma(0)=sqrt(M&Sigma2+|p'&Sigma|2),

Nucleon 4-momentum pN(0:3)/3-momentum p'N(3):pN(i)=p'N(i) (i=1,2,3), pN(0)=sqrt(MN2+|p'N2|)

cos(N&Sigma):p'&Sigma*p'N/(|p'&Sigma|*|p'N|)

N&Sigma total 3-momentum Ptot:sqrt((p&Sigma(1)+pN(1))2+(p&Sigma(2)+pN(2))2+(p&Sigma(3)+pN(3))2)

N&Sigma total energy Etot:p&Sigma(0)+pN(0)

N&Sigma invariant mass Minv:sqrt(Etot2-Ptot2)

4He(stopped K-,N&Sigma)X missing mass Mmiss:sqrt((M4He+MK--Etot)2-Ptot2)

The results are exhibitted below for all event topologies:
  • &Sigma case 1 p 180degree
  • &Sigma case 1 p 90degree
  • &Sigma case 1 n 180degree
  • &Sigma case 1 n 90degree
  • &Sigma case 2 p 90degree
  • &Sigma case 2 p 180degree
  • &Sigma case 2 n 90degree
  • &Sigma case 2 n 180degree
  • &Sigma case 3 p 90degree
  • &Sigma case 3 n 90degree