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L0 Confirmation using the T stations (Hadron alley)

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Finally a decision has to be made on the theshhold above which we assume the energy deposit in the ECAL is associated to the hadron shower. As a guide, we look at the S-curves in the ECAL as a function of four energy (not E_T!) cut-offs. To partially remove the noise tails seen at the edges of the curves, a energy cut of 1000MeV and 500MeV is applied for the inner and middle part of the ECAL. No cut is deemed necessary for the outer part.
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Benefit to the energy resolution from including ECAL information

Energy precision is seen to improved with using ECAL information:

Predicting the particle track into the T-stations

To predict the track of the L0 Candidate, it is assumed the particle has followed a straight line from the IP (0,0,0) in y. For x, the deviation from a straight line due tothe magnetic field is assumed to be inversely proportional to the particle's energy. See the following sketch by Herve...

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The parameter "alpha" is obtained from a 350k minimum bias Monte Carlo sample and is recorded in the following table:

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Where ECAL information is used to define the x-y co-ordinate of the L0 candidate cluster, z=12830mm is the assumed starting point in the ECAL. Where no ECAL information is used z=13690mm is used. If the ECAL is used, the energy used in the projection is the sum of the deposit seen in the the HCAL 2x2 cluster plus than in the ECAL 2x2 cluster.

 x10^6 T1 T2 T3 IT OT IT OT IT OT
Changed:
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<
 HCAL 2.8 2.78 2.52 2.47 2.21 2.15
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 assumed z (mm) 7760 7939 8447 8625 9138 9317

 ECAL 2.56 2.52 2.25 2.2 1.92 1.85
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 HCAL 2.8 2.78 2.52 2.47 2.21 2.15

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Line: 87 to 95

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