[PWGDQ] fix MFT momentum rescaling - #17461
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The MCH tracks are extrapolated to the first measured MFT point using TrackExtrap::extrapToVertex() instead of TrackExtrap::extrapToVertexWithoutBranson(), which cures large inaccuracies in the MCH momentum estimation at the MFT front for some tracks. Those inaccuracies were contributing to high-mass tails in the di-muon invariant mass distribution reconstructed from global forward tracks with rescaled momentum.
aferrero2707
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XiaozhiBai,
alibuild,
iarsene,
mcoquet642 and
mguilbau
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August 14, 2026 13:59
aferrero2707
marked this pull request as draft
August 14, 2026 13:59
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O2 linter results: ❌ 0 errors, |
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why not use the common tool for rescaling introduced in |
Contributor
Author
Mostly to have the freedom of experimenting without affecting the common tools used in analysis. Once the fix is confirmed we can see how to properly propagate it to the common code. What do you think? |
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The MCH tracks are extrapolated to the first measured MFT point using
TrackExtrap::extrapToVertex()instead ofTrackExtrap::extrapToVertexWithoutBranson(), which cures large inaccuracies in the MCH momentum estimation at the MFT front for some tracks.Those inaccuracies were contributing to high-mass tails in the di-muon invariant mass forward tracks with rescaled momentum.
Below is a comparison of the J/psi invariant mass before and after the fix, estimated from the same AO2Ds of LHC25i4 (OO MC simulation with injected J/psi and psi(2S)).
Before:
After:
