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RICH efficiency versus p/pth

- merging low and high field settings

Incorporating different inefficiency components =>

RichInefficiencyModule

Paweł Staszel

Jagiellonian University

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At high fields inefficiencies for A and B polarities are different

It is due to different pion+kaon and proton contributions

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Extracting pions+kaon and protoninefficiency

(1)

All coefficients are known, so,this set of equations can be solved in respect to f

π and f

p

for each momentum bin

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Results for 2A3450 + 2B3450

Cut on x-slope makes the inefficienciesfree from “geometrical” effect allowing to extract pure “gamma factor”inefficiency

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Results for all possible settings

Rich vs Tof2

X-slope>0.01 => pure “gamma factor” effect

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Fitting low and high part of p/pth

Usual inefficiency formula Ordinary exponent with build-in matching to low p/p

th

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Zoom in at low p/pth

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Zoom in at high p/pth

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Strategy for RichEfficiencyModule We have to deal with 3 effects:

1. “gamma factor” effect Eγ

2. “x-slope (geometrical)” effect Eg

3. two track resolution effect Er

It is fair to assume that these effects are independent, if so,the total efficiency is a product of individual efficiencies:

For small inefficiencies:

But in general:

See attached note on two track resolution

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Problem: not all fsTrack are reconstructed

Using condition #T5tracks = 1 versus no condition on #T5Tracks give small effect because usually #fsTracks = #T5Tracks,

Events with #T5Tracks > 1 (#T5Tracks=2) looks similar to events with #fsTracks==2.

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Same effect at high fields (2 deg)

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Same effect at high fields (4 deg)

Possible strategies: 1) add x/y - slope info for each T5 track and redo dsts2) apply an average efficiency related to two track resolution determinedfrom events with #fsTracks=2.

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How to use RichEfficiencyCalculator

The calculator is in banapp/corrections/efficiency

RichEfficiencyCalculator* richEffCal=new RichEfficiencyCalculator(“run04”,”auau”,”200”);richEffCal->Init();

in event loop:

richEffCal->CalculateEffectiveEfficiencies(multi,d12,d13,d23);(see attached note)

if track loop:Float_t InEff = richEffCal->GetInEffic(i,t5ax,p/pth);orFloat_t Eff = richEffCal->GetEffic(i,t5ax,p/pth);