- BEMC
- EEMC
- ETOF
- FCS
- FGT
- FGT. . . . . . . . . . I N S T R U C T I O N S
- FGT. . . . . . . . . . P H Y S I C S
- FGT. . . . . . . . . . S I M U L A T I O N S
- FGT. . . . . . . . . H A R D W A R E -- D E T E C T O R
- FGT . . . . . . . . . . A N A L Y S I S
- Estimation of error of A_L including detector response, May 2008 (Jan)
- study 1 of S/B, A_L, LT=800/pb (Jan)
- study 2 , err(AL) , eta=[1,2], LT=800/pb (Jan)
- study 3 , cross check w/ FGT proposal, LT=800/pb (Jan)
- study 4 , LT=300/pb, eta=+/-[1,2] , W+/- (Jan)
- study 5 charge sign discrimination
- study 6 final plots for PAC, May 2008
- study 7 revised for White Paper, AL(eta), AL(ET) , (Jan)
- study 8 no QCD backg AL(eta), AL(ET), also rapidity (Jan)
- study 9 sensitivity of STAR at forward & mid rapidity
- study 9a sensitivity mid rapidity LT=10/pb
- study 9b sensitivity at mid rapidity LT=10/pb Pol=50% or 60%
- e/h algo for Barrel
- e/h discrimination in the Endcap
- Estimation of error of A_L including detector response, May 2008 (Jan)
- FGT . . . . . . . . . . C A L I B R A T I O N
- FGT . . . . . . . . . . D O C U M E N T S
- FGT . . . . . . . . . . DAQ
- FGT . . . . . . . . . . M E E T I N G S
- FGT. . . . . . . . . . H A R D W A R E -- E L E C T R O N I C S
- FGT. . . . . . . . . . H A R D W A R E -- S L O W C O N T R O L S
- FGT. . . . . . . . . . P H O T O - - G A L L E R Y
- FGT. . . . . . . . . . S O F T W A R E
- FGT. . . . . . . . . . V A R I A
- FGT. . . . . . . . . . x -T R A S H (node for recycling)
- FPD & FMS & FPS
- FTPC
- FTT
- HLT
- L3
- PMD
- PP2PP
- RICH
- Roman Pot Phase II*
- SSD
- SVT
- Slow Controls
- TPC
- TRG
- Trigger Detectors
- VPD
- test
study 1 of S/B, A_L, LT=800/pb (Jan)
Updated on Tue, 2008-05-13 11:45. Originally created by balewski on 2008-04-28 15:32.
Under:
A_L on this has a WRONG sign, I did not know RHICBOS is using different sign convention
Section A
Definitions:
S1,S2 - "signal" yields for 2 spins states (helicity) "1", "2" , S1+S2=S
B1,B2 - "background" yields for 2 spins states "1", "2" , B1+B2=B
N1=S1+B1; N2=S2+B2; N1+N2=N=S+B - "raw" yields measured in real experiment
Assumptions:
- background is unpolarized, so B1=B2=B/2
- there are 2 independent experiments:
- measure spin independent yields for signal counts 's' and background 'b' counts, yielding the fraction w=b/s, V(w)=w2 *(1/b +1/s) ; (e.g. M-C Pythia simulation using W and QCD events)
- measure helicity dependent raw yields N1=S1+B1 and N2=S2+B2 ; (e.g. theory calculation with specific assumption of AL(W+) , fixed eta & pT ranges, assumed LT & W reco efficiency) yielding raw spin asymmetry :
ALraw=(N1-N2)/(N1+N2)= (S1-S2)/(S+B); V(ALraw)= 4*N1*N2/N3
I used capital & small letters to distinguish this two experiments.
Problem: find statistical error of 'signal' asymmetry:
ALsig= (S1-S2)/S
Solution:
- ALsig= (1+w) * ALraw
- V(ALsig)= (1+w)2*V(ALraw ) + V(w)*(ALraw)2 where V(x) denotes variance of x, V(N)=N.
Section B - theory
Model predictions of A_L for W+, W- , used files:
rb800.w+pola_grsv00_2.root, rb800.w-pola_grsv00_2.root, rb800.w+unp_ct5m.root rb800.w-unp_ct5m.root
LT=800/pb,
Brown oval shows approximate coverage of IST+FGT
Red diamond shows region with max A_L and ... little yield.
Section C - W reco efficiency, fixed ET using fact=1.25
From Brian, e/h algo ver 2.4, LT=800/pb.
This version uses only tower seed in bin 6-11, this is main reason efficiency is of 40%.
I'll assume in further calculation the W-reco efficiency is of 70%, flat in lepton PT>20 GeV.
Left: W-yield black=input, green - after cut 15.
Right: ratio. h->Smooth() was used for some histos.
PT=20.6 sum1= 1223 PT=25.6 sum1= 1251 sum2= 473 att=1/2.6 PT=30.6 sum1= 987 sum2= 406 att=1/2.4 PT=35.6 sum1= 771 sum2= 343 att=1/2.2 PT=40.6 sum1= 372 sum2= 166 att=1/2.2 PT=45.6 sum1= 74 sum2= 16 att=1/4.6
Section D - QCD reco efficiency,fixed ET using fact=1.25
From Brian, e/h algo ver 2.4, LT=800/pb. h->Smooth() was used for some histos.
This version uses only tower seed in bin 6-11
Left: QCD-yield black=input, green - after cut 15.
Right: ratio= QCD attenuation, not the a;go gets ~3x 'weaker' at PT =[34-37] GeV , exactly where we need it the most
PT averaged attenuation of QCD events
PT=20.6 sum1=2122517 PT=25.6 sum1=528917 sum2=3992 att=1/133 PT=30.6 sum1=135252 sum2= 736 att=1/184 PT=35.6 sum1= 38226 sum2= 320 att=1/120 PT=40.6 sum1= 11292 sum2= 127 att=1/89 PT=45.6 sum1= 3153 sum2= 41 att=1/77
Section E - QCD/W ratio after e/h cuts, algo ver 2.4,fixed ET using fact=1.25
From Brian. h->Smooth() was used for some histos.
Left: final yield of QCD events (blue) and W-events (green) after e/h algo.
Right: ratio.
I'll assume w=b/s is better than the red line, a continuous ET dependence:
w(pt=20)=10
w(pt=25)=1.
w(pt=40)=0.5
PT=25.6 sum1= 3992 sum2= 473 att=1/8.4 PT=30.6 sum1= 736 sum2= 406 att=1/1.8 PT=35.6 sum1= 320 sum2= 343 att=1/0.9 PT=40.6 sum1= 127 sum2= 166 att=1/0.8 PT=45.6 sum1= 41 sum2= 16 att=1/2.5
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