Low Energy photon studies

Fig.1a Inv Mass vs: Epi0, Egamma1/Egamma2, Egamma2

Fig.1b As Fig.1a with cut Angle(e,gamma1(2))>12

Fig.1c As Fig.1a with cut Egamma2>0.3

Fig.1d As Fig.1a with cut Egamma2>0.3 & opening_angle(Egamma)


N.B. Note, energy cut on Egamma equivalent to a cut on the Edeposited/0.273 (before E correction)

Fig.2a Left: Opening Angle of 2gamma as a fnc of their E.
Right: Opening Angle of 2gamma as a fnc of their inv Mass


Fig.2b Left: Opening Angle of 2gamma as a fnc of Angle(electron,gamma).
Middle: Opening Angle of 2gamma vs E of 2gamma. Right: as Middle + Egamma>0.3


Fig.3 Photon Energy Correction fnc for C(red) and Fe(blue) vs Edep/0.273
Correction for C at Edep/0.273 = 0.15 is 25%, resolution - 28%


Effect of Egamma>0.3 on result
Fig.4a Mass distribution for 6 targets in z bins (6x9) :
Left: Egamma>0.15GeV(current default). Right: Egamma>0.3GeV
Note: Background parametrs are not fixed here, curvatures are set negative.


Fig.4b


Fig.5 Photon X vs Y coordinate in EC for each sector.
Left(3x2): all photons with E>0.15. Right(3x2): E<0.3 & |Pi0Mass-0.135|>5*0.02


Fig.