Today's Progress 27. May. 2007

Event selection on TC-related variables and charged particle spectra on TC: E570

Method

As was done for E549 cycle data, we activate event selection on TC system, with 1/&beta on A, &Delta E on A, B, C layers, D layer digital hits, and VDC-detected track information. The definition of 'p','&pi','fast-&pi','slow-&pi', and so on are set to be completely identical to E549 definition found here and here . For E570 2 cycle data, the run-by-run stability of the event selection is checked once arm-by-arm.

Charged particle spectra by B/C

Now, 1/&beta for TC-detected charged particle, X, is defined as follows:

TOF_X = Ttc_b' - Tt0 - TOFkstop(z),

Ttc_b' = Ttc_b - f(1/ph)*g(x) -const(idpart),

where TOF_X is the Time-Of-Flight of X. the functions f/g are adopted as they are defined by Compton-like &gamma-ray. Then, 1/&beta_X is defined as

1/&beta_X = c*TOF_X/L_TOF,

L_TOF = sqrt((TC_x-Vx)**2+(TC_y-Vy)**2+(TC_z-Vz)**2,

where TC_x, TC_y, and TC_z are defined by VDC at the inner-surface y position now.

The layer-by-layer 1/&beta spectra and its decomposition to p/&pi components are shown below.

Segment-by-segment plot of 1/&beta for charged particles on B/C top/bottom layers. ID 1/2/3/4/5 are represented by black/red/green/yellow/magenta colors, respectively.

The comparison of 1/&beta spectra detected on B/C layers Black/red/green/yellow are used to represent Btop/Bbottom/Ctop/Cbottom, respectively.

The 1/&beta spectra for all(black)/p(red)/&pi(green)/fast&pi(yellow)/slow&pi(magenta) events on TC B layer.

The 1/&beta spectra for all(black)/p(red)/&pi(green)/fast&pi(yellow)/slow&pi(magenta) events on TC C layer.

Layer-by-layer 2D-plots between 1/&beta and Light output are shown below.