Today's Progress 15. May. 2007

NT time walk study by (stopped K-, X+/-) data : E570

Since we have determined T0/PA/PB offset well, determine NT run-by-run offsets here with Kmu2 peak.

Method

We try to follow the NT time walk again by delayed-event, defined by the condition,

&delta T(T0->PA) = Tpa - Tt0 -TOFkstop -TOFsec > 1.2 (nsec) ,

with the finalized &delta T(T0->PA) and PA-PB TOF analysis to calculate TOFsec. For NT, 7 layers are treated separately - i.e. run-by-run offsets are studied layer-by-layer. After the run-by-run but layer-by-layer offset tune has been terminated, production runs are divided into 35 parts as has been performed for PB in the previous report (part division is identical), and NT segment-by-segment offset will be studied part-by-part. Since PA time offsets are well investigated, this procedure is not iterative, and terminated at once. Now, we study the Gaussian center of the quantity,

&delta T(PA->NT) = Tnt - Tpa - TOFKmu2 ,

where Tnt is the value defined at the K^+ runs, and Tpa is the one which has been established by T0-PA-PB iterative procedure, and Kmu2 events are selected by the condition, 1.04 < 1/beta(PA-PB) < 1.16 .

Layer-by-layer (run-by-run) tune

The results of run-by-run but layer-by-layer tune are exhibitted below.

The Layer-by-layer central position of Kmu2 time residual of NT Larm.
Center of time residual of Kmu2 peak for NT Larm
The Layer-by-layer central position of Kmu2 time residual of NT Rarm.
Center of time residual of Kmu2 peak for NT Rarm
The Layer-by-layer Gaussian Sigma of Kmu2 time residual of NT Larm.
Time resolution of PA-NT Larm for Kmu2 peak
The Layer-by-layer Gaussian Sigma of Kmu2 time residual of NT Rarm.
Time resolution of PA-NT Rarm for Kmu2 peak

We introduce the run-by-run layer-by-layer offset, NT_LAYER_OFFSET(idrun,nlayer), as

NT_LAYER_OFFSET(idrun,nlayer) = Gaussian center of deltaT(PA->NT) .

Segment-by-segment (part-by-part) tune

After activating the NT_LAYER_OFFSET(idrun), we study

&delta T(PA->NT)' = Tnt' - Tpa - TOFKmu2 ,

where

Tnt' = Tnt - NT_LAYER_OFFSET(idrun,nlayer) .

Then, we introduce the segment-by-segment part-by-part offset, NT_SEG_OFFSET(ipart(idrun),ntid), by

NT_SEG_OFFSET(ipart,ntid) = Gaussian center of &delta T(PA->NT)' .

Obtainning the NT_SEG_OFFSET(ipart,ntid), we examine the run-by-run performance of

&delta T(PA->NT)'' = Tnt'' - Tpa - TOFKmu2 ,

where Tnt'' = Tnt' - NT_SEG_OFFSET(ipart,ntid). The layer-by-layer run-by-run performance of &delta T(PA->NT)'' is exhibitted below.

1. Layer-by-layer results

The Layer-by-layer central position of Kmu2 time residual of NT Larm.
Center of time residual of Kmu2 peak for NT Larm
The Layer-by-layer central position of Kmu2 time residual of NT Rarm.
Center of time residual of Kmu2 peak for NT Rarm
The Layer-by-layer Gaussian &sigma of Kmu2 time residual of NT Larm.
Time resolution of PA-NT Larm for Kmu2 peak
The Layer-by-layer Gaussian &sigma of Kmu2 time residual of NT Rarm.
Time resolution of PA-NT Rarm for Kmu2 peak
The Layer-by-layer PA-NT 1/&beta spectrum for delayed events with E570 1st cycle total statictics. Black, red, green, yellow, magenta, sky-blue, and black for 1,2,3,4,5,6 and 7th layers, respectively.
Time resolution of PA-NT Larm for Kmu2 peak Time resolution of PA-NT Rarm for Kmu2 peak
The Layer-by-layer PA-NT 1/&beta spectrum for delayed events with E570 2nd cycle total statistics. Time resolution of PA-NT Rarm for Kmu2 peak Time resolution of PA-NT Rarm for Kmu2 peak

Segment-by-segment results

E570 cycle1 results. The red is the 1/&beta spectrum when 1.04 < 1/&beta < 1.16 has been imposed on PAPB.
E570 cycle2 results

Segment-by-segment resolution estimated by Gaussian sigma value for K- Kmu2 peak identified as 1/&beta (PAPB) value being 1.04~1.16 is shown below.