γ+ d → p + p + π- Analysis Status

Y.C.Han@NKS2 Meeting

Dec20, 2007

Outline

• Debug in source and macro file

• Check analysis method w/ simulation

• Analysis of Jan2007’s experiment data

Debug

• In source file P3TrVertex3D.cpp1. debug three tracks’ rotation angle;

2. return track’s momentum w/ mean values in two

2TrVertex reconstruction • In root macro files Correct the mixing use of three tracks’ momentum

• Simulation Some changes of Generator

upgrade the formater

Check analysis method w/ simulation

1. Check simulation’s 3BPS generator uniform or not

2. Compare simulation data before and after analysis by check the geometrics and kinematics

center of mass frame

L1: p1

L2: p2

L3: π-

( MeV )

Uniform??

The theta distibution don’t show uniform ?

laboratory frame

L1: p1

L2: p2

L3: π-

( MeV )

The method needs improve on Z Axis

How to understand the two peaks tendency ?

Peak less than PDG Mass ~24MeV

Analysis of Jan2007 exp data

• The data is under analyzed. There are about 70% data finished until this morning. The following are some of the preliminary check for these part data.

w/o cut

LVp1(MomP1, Ep1);

LVp2(MomP2, Ep2);

LVpi (MomPi, Epi);

LVg(Momg, Eg);

LVTar=LVp1+LVp2+LVpi-LVg;

W/ PDG mass

w/ reconstruct target mass cut

Simulation

Simulation

w/ reconstruct target mass cut

The difference from simulation is from ground, fluctuation due to small events #,

or simple simulation ?

w/ reconstruct target mass cut

c.f. LVmiss W/O cut