Run 12 CuAu200

Regarding the P14ia Preview Production of Run 12 CuAu200 from early 2014:

A check-list of observables and points to consider to help understand alayses' sensitivity to non-final calibrations

To unambiguously see issues due to mis-calibration of the TPC, stringent determination of triggered-event tracks is necessary. Pile-up tracks are expected to be incorrect in many ways, and they constitute a larger and larger fraction of TPC tracks as luminosity grows, so their inclusion can lead to luminosity-dependencies of what appear to be mis-calibrations but are not.

1. TPC dE/dx PID (not calibrated)
   1. differences between real data dE/dx peaks' means and width vs. nsigma provided in the MuDst
   2. variability of these differences with time
2. TPC alignment (old one used)
   1. sector-by-sector variations in charge-separated signed DCAs and momentum spectra (e.g h-/h+ pT spectra) that are time- and luminosity-independent
   2. differences in charge-separated invariant masses from expectations that are time- and luminosity-independent
   3. any momentum effects (including invariant masses) grow with momentum: delta(pT) is proprotional to q*pT^2
      1. alternatively, and perhaps more directly, delta(q/pT) effects are constant, and one could look at charge-separated 1/pT from sector-to-sector
3. TPC SpaceCharge & GridLeak (preliminary calibration)
   1. sector-by-sector variations in charge-separated DCAs and momentum spectra that are luminosity-dependent
   2. possible track splitting between TPC pad rows 13 and 14 + possible track splitting at z=0, in the radial and/or azimuthal direction
   3. differences in charge-separated invariant masses from expectations that are luminosity-dependent
   4. any momentum effects (including invariant masses) grow with momentum: delta(pT) is proprotional to q*pT^2
      1. alternatively, and perhaps more directly, delta(q/pT) effects are constant, and one could look at charge-separated 1/pT from sector-to-sector
4. TPC T0 & drift velocities (preliminary calibration)
   1. track splitting at z=0, in the z direction
   2. splitting of primary vertices into two close vertices (and subsequent irregularities in primary track event-wise distributions)
5. TOF PID (VPD not calibrated, BTOF calibration from Run 12 UU used)
   [particularly difficult to disentangle from TPC calibration issues]
   1. not expected to be much of an issue, as the "startless" mode of using BTOF was forced (no VPD) and the calibration used for BTOF is expected to be reasonable
   2. broadening of, and differences in mass^2 peak positions from expectations are more likely due to TPC issues (particularly if charge-dependent, as BTOF mis-calibrations should see no charge sign dependence)
   3. while TOF results may not be the best place to identify TPC issues, it is worth noting that BTOF-matching is beneficial to removing pile-up tracks from studies