VERTEX RESIDUAL STUDY

J. Hamblen
University of Rochester

This study explores the degree to which sensor misalignment affects vertex resolution.   Sensors in the top vertex detector were shifted in various ways in order to simulate a misalignment, and the residual difference between the the reconstructed vertex z position and the monte carlo z position was calculated for 500 events.  The table below shows what sensors were shifted, the shift direction and amount, as well as the mean and sigma of the fitted residual histogram.  A flat shift stands for an individual, random shifting of all sensors within the range of +/- 200 microns.

Sensor(s)

Shift Amt.
Local X (cm)

Shift Amt.
Local Z (cm)

Mean of Distribution

Sigma of Distribution

Unshifted

0

0

-0.01491+-0.0017

-0.02081+-0.00126

VTA

0.02

0

0.02505+-0.02489

0.0219+-0.02464

VTA

0

0.02

0.004856+-0.004

0.04258+-0.00577

VTB

-0.02

0

0.004627+-0.0019

0.02106+-0.0023

VTB

0

-0.02

 -0.009025+-0.002

0.02831+-0.00139

Flat Shift 1

[-0.02,0.02]

0

-0.02363+-0.0029

0.02672+-0.00309

Flat Shift 2

[-0.02,0.02]

0

-0.02076+-0.0022

0.02264+-0.00303

Flat Shift 3

0

[-0.02,0.02]

-0.008962+-0.002

0.02579+-0.00197

Flat Shift 4

0

[-0.02,0.02]

-0.0114+-0.00188

0.02126+-0.00177

Flat Shift 5

[-0.02,0.02]

[-0.02,0.02]

0.00949+-0.0022

0.0259+-0.001596

Flat Shift 6

[-0.02,0.02]

[-0.02,0.02]

-0.01044+-0.0031

0.03217+-0.00381