Photon Event Mixing

PART0. Mixing Methods

TOP Photon i from event1 is mixed with photon j=0,1... of event2. Electron in (Q2,Nu)bins. C+Fe+Pb+D targets.
MIDDLE1 Photon i from event1 is mixed with j=(i+1),(i+2),.. of event2. Electron in (Q2,Nu)bins. C+Fe+D targets.
MIDDLE2 Photon mixing is the same as MIDDLE1. Electrons arent required to be from the same (Q2,Nu) bins. C+Fe+D targets.
BOTTOM Photon i from event1 is mixed with j= 1,2... of event2 if! E(j-1)>E(i). All Electrons. C+Fe+D targets.

Fig.1 Invariant mass of uncorrelated pair of photons. Z bins.





Fig.2 Invariant mass of uncorrelated pair of photons. pT bins.





Fig.3 Invariant mass of uncorrelated pair of photons. Q2 bins.





Fig.4 Invariant mass of uncorrelated pair of photons. Nu bins.






Fig.5 InvMass vs Opening Angle for Z>0.8. Left - Data; MIddle - 'Top' method; Right - 'Bottom' method.



PART1. Mixing ALL uncorrelated photons.

Fig.0 Epi0 vs Opening Angle in mass slices; TOP panel - Event Mix; Bottom - Data
Here Event Mixing Scale is normalized to number event in Data
Mass slices correspond to {0,-5sigma, -3sigma, 0.135, 3sigma, 5sigma, 0.3} with sigma = 0.02GeV


Fig.2 Z vs pT2 in mass slices; TOP panel - Event Mix; Bottom - Data




Mixed Background for different targets
Fig.1 5x5 bins in (Z,pT2). Solid target with their D(green): Left-C(red); Middle -Fe(blue); Right-Pb(black)

Fig.2 5x5 bins in (Z,pT2). Solid targets only: Left-C(red); Middle -Fe(blue); Right-Pb(black)



1D Mixed Background
Fig.1a 1D in bins of Z :POL2(top),POL3(middle),POL4(bottom) background fits to the mixed events :



Fig.1b Mass distribution with backgrounds 6x9(Target x Zbin) panels:
unfixed POL2(left), fixed POL3(middle), POL4(right):


Fig.1c MUltiplicities for corresponding background, same order as Fig.1b:


Fig.2a 1D in bins of pT2 : POL4 background fit to the mixed inv mass :

Fig.2b Mass distribution with backgrounds 6x9(Target x pTbin) panels:
unfixed POL2(left), POL4(right):


Fig.2c MUltiplicities Rvs pT:


Fig.3a 1D in bins of Q : POL4) background fit to the mixed inv mass :

Fig.3b MUltiplicities Rvs Q:


Fig.4a 1D in bins of Nu : POL4 background fit to the mixed inv mass :

Fig.4b MUltiplicities Rvs Nu:


2D Mixed Background
Fig.5 Z(horozontaly) and pT2 (vertically) bins

Fig.6a Z(horozontaly) and Q2 (vertically) bins

Fig.6b Z(horozontaly) and Nu (vertically) bins

Fig.7a pT(horozontaly) and Q2 (vertically) bins

Fig.7b pT(horozontaly) and Nu (vertically) bins



T E S T S

Compare 1D case of mixed event from DATA(mixed photons are from diff events)
and MC(generated photons mixed if they do not have the same parent):
Fig.9a Z bins. Mixed Background for Data(top, YELLOW) and MC(bottom,PINK)

Fig.9b pT2 bins. Mixed Background for Data(top, YELLOW) and MC(bottom,PINK)

Fig.9c Nu bins. Mixed Background for Data(top, YELLOW) and MC(bottom,PINK)

Fig.9d Q2 bins. Mixed Background for Data(top, YELLOW) and MC(bottom,PINK)



Fig.10 Mixed background for Fe(blue) and D(green) in bins: Q2_Nu_Z_pT2 (2x2x3x3)


Fig.10a POL3 Fit to the above distribution for Deuterium:


Fig.11 Deuterium. Mixed background in horizontal-vertical increment: Z_pT2 (9x9), POL3 fit.