Recent studies have demonstrated improved matching between simulations and real data by including additional smearing of calibration parameters for use in simulations (but not in reconstruction) that represent how well those parameters track reality in the data. For example, a calibration parameter may reflect a mean value of some aspect such as SpaceCharge, but would not otherwise encapsulate fluctuations in the SpaceCharge about that mean value for the parameter. An example of where to use such resolutions is in the DoDistortions() method of the StDbUtilities/StMagUtilities class, not using the resolutions in the UndoDistortion() method.

To that end, I propose a new DB table which will begin with parameters for smearing TPC SpaceCharge & GridLeak, and would potentially be later expanded to include additional parameters. This would be placed under Calibrations_tpc in the DataBase structure.

/*    tpcCalibResolutions.idl
*
*  Table: tpcCalibResolutions
*
*       description: Table for Resolutions of TPC Calibrations
*/


struct tpcCalibResolutions {

   float   SpaceCharge;     /* SpaceCharge correction */
   float   GridLeak;        /* GridLeak correction */
   char    comment[255];    /* comments */

 };

-Gene