Sterile@PS - E313
Max e Gabriele
Uscenti dal near: 47%
Uscenti dal far: 32%
Range
MCS
Distanza in LAr
Momentum reconstruction: RPC
• No digits (solo hits)
• No track-finding (fit diretto sugli hit a disposizione)
• Fit parabolico in XZ (bending), lineare in YZ (not-bending)
Momentum reconstruction: PT
l
•
•
•
In each side of the magnet arm we can reconstruct an independent angle fj, j=1,...,6.
Each fj can be reconstructed with one station (singlets) or two stations (doublets)
We compute Dfk = fi – fj , k=1,...,4, angle differences between adjacent station-pairs
– 55% of Df’s comes from doublets
– 9% from singlets
– 36% are mixed
xz
1  exp[ Df (dE / dx) / e B]
p 
k
l (dE / dx)
1
1 s2
s yz2
B ≡ Bd/l =
effective magnetic field
M. Sioli - SLAC Experimental Seminar - June 22, 2010
4
Charge reconstruction
• Charge is reconstructed according to the Df sign
• If each track contributes to multiple Df angles, a weighted
average is computed
– weights = experimental errors on Df
p

k 1
4
pk
k

k 1
Cross-check with beam data
4
4
k
q

k 1
4
k

k 1
qk
k
Rm = (1.9 ± 0.9) %
where
 
1
 2 (D ) k
pm
M. Sioli - SLAC Experimental Seminar - June 22, 2010
5
p and q reconstruction: E313
•
•
•
•
•
Arrivano al 1 arm: 26%
Passano il 1 arm: 19%
Passano anche il 2 arm: 14%
q-misid(RPC, 1 arm) ~ 13%
q-misid(DT, 1 arm) ~ 5%
RPC
DT
• dp/p da capire:
– Bias
– Risoluzione
20%
26%