Change pT5 rz chi2 cut definition into helix approximation (rebase PR40)

[ariostas]

This is a rebase of PR #40. Since it changes the performance I made it as its own PR so that we can compare the plots with the original PR.

[ariostas]

/run all

[github-actions]

The PR was built and ran successfully in standalone mode. Here are some of the comparison plots.

The full set of validation and comparison plots can be found here.

Here is a timing comparison:

   Evt    Hits       MD       LS      T3       T5       pLS       pT5      pT3      TC       Reset    Event     Short             Rate
   avg     40.9    384.6    191.2    127.0    135.1    501.4    117.8    243.5    102.0      3.2    1846.5    1304.2+/- 362.3     491.8   explicit[s=4] (target branch)
   avg     40.5    383.9    191.0    128.8    136.8    499.8    106.6    244.6    101.9      2.8    1836.7    1296.4+/- 358.2     488.5   explicit[s=4] (this PR)

[github-actions]

The PR was built and ran successfully with CMSSW. Here are some plots.

OOTB All Tracks

The full set of validation and comparison plots can be found here.

[YonsiG]

It is a bit weird that this line and the Line 628 are added into this PR, it seems pure pT3 rzchi2 work.

[ariostas]

Thank you, @YonsiG. Seems like I might have messed something up. I'll fix it.

[ariostas]

Actually, if you look at #40, those changes were made for pT3 rzchi2. Either way, those changes shouldn't affect anything.

[YonsiG]

Yes, those are for pT3 rzchi2. The order doesn't affect much as you said.

[YonsiG]

I think to reproduce PR #40 , this PR looks good to me. The plot before this PR baseline is a bit different. Other than that, this PR should be good to merge.

[ariostas]

I switched the changes to computePT5RZChiSquared even though originally they were applied to computePT3RZChiSquared. Regardless, they are more of a style change since the logic is the same. The plots could look a bit different because things were merged in a different order. I'll re-run the standalone test just to make sure that I didn't break anything.

/run standalone
/run checks

[github-actions]

The PR was built and ran successfully in standalone mode. Here are some of the comparison plots.

The full set of validation and comparison plots can be found here.

Here is a timing comparison:

   Evt    Hits       MD       LS      T3       T5       pLS       pT5      pT3      TC       Reset    Event     Short             Rate
   avg     41.5    382.9    184.1    130.5    136.3    548.1    119.3    247.1    142.2      3.0    1935.2    1345.5+/- 376.2     514.5   explicit[s=4] (target branch)
   avg     43.0    390.6    186.8    129.2    135.7    506.9    109.1    254.5    137.1      2.8    1895.5    1345.7+/- 375.7     503.4   explicit[s=4] (this PR)

[YonsiG]

Thank you Andres, these looks good and I will merge it