Ronen Ingbir
description
Transcript of Ronen Ingbir
Ronen Ingbir
Collaboration High precision design
Tel Aviv University HEP Experimental Group
Krakow2006
Eve
nts
(rad)
CollaborationHigh precision design Krakow2006
Energy (GeV)E
vent
s
Bhabha Scattering
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
Bhabha Scattering
Head-on
(rad) X (cm)
Y (
cm)
Eve
nts
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
(rad) X (cm)
Y (
cm)
Eve
nts
Bhabha Scattering
20mrad X-angle
Detector axis
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
(rad) X (cm)
Y (
cm)
Eve
nts
Bhabha Scattering
20mrad X-angle
Outgoing beam
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
(rad)
X (cm)
Y (
cm)
Eve
nts
(rad)E
vent
s
X (cm)
Y (
cm)
Outgoing beam flat azimuthal distribution
Tel Aviv University HEP Experimental Group
N1 : Reconstructed and generated in acceptance region.
N2 : Generated in acceptance region but reconstructed outside.
N3 : Generated outside acceptance region but reconstructed inside.
CollaborationHigh precision design
21
23rec
NN
NN
N
NN
N
N
L
L
gen
gen
2
21
2221
2231
2223 321
NN
NNNNNN
L
L NNN
Luminosity precision determination
Krakow2006 Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
No
Yes
Counting Bhabha events
MinMax
R~10 cm~25 cm
θ33 mrad80 mrad
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
Headon, 14,20 mrad X-angle outgoing beam
14 mrad X-angle detector axis
20 mrad X-angle detector axis
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
Headon, 14,20 mrad X-angle outgoing beam
14 mrad X-angle detector axis
20 mrad X-angle detector axis
Δz
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
Δr
ΔzΔz
Δr
Bhabha Scattering
Outgoing beam
dL/L = 10-4
0
0.0020.004
0.006
0.0080.01
0.012
0.0140.016
0.018
0.0E+001.5E-043.0E-044.5E-046.0E-04
dr (cm)
dz
(cm
)
ΔL/L=10-4
Collaboration
High precision design Krakow2006
Headon, 14,20 mrad X-angle outgoing beam
14 mrad X-angle detector axis
20 mrad X-angle detector axis
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
Headon, 14,20 mrad X-angle outgoing beam
14 mrad X-angle detector axis
20 mrad X-angle detector axis
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
1. Bhabha events sample will not be pure (background).
2. Magnetic field changes the distribution (could be a dramatic effect if not aligned with the outgoing beam).
3. Event position and energy reconstruction is not perfect.
4. To evaluate the real error on luminosity one should apply MC – DATA corrections.
Are these numbers realistic ?
Tel Aviv University HEP Experimental Group
X- angle background
CollaborationHigh precision design
Christian Grah, DESY-Zuethen
Beamstrahlung pair background
0.E+00
1.E+09
2.E+09
3.E+09
4.E+09
5.E+09
6.E+09
8 9 10 11 12 13 14 15 16
R min (cm)
Num
ber
of B
habh
a ev
ents
per
ye
ar
0
500
1000
1500
2000
2500
3000
3500
Bac
kgro
und
(GeV
)
Events per year
Background (GeV)
250 GeV
Krakow2006 Tel Aviv University HEP Experimental Group
20 mrad, DID
20 mrad, anti DID
Collaboration
High precision design Krakow2006
Magnetic field along the outgoing beam
),,,,( EnergyBzByBx
Tel Aviv University HEP Experimental Group
Fast detector simulation – bias
min
*2
L
L
Changing the bias with a fixed resolution.
CollaborationHigh precision design Krakow2006
Tel Aviv University HEP Experimental Group
Changing the detector resolution with no bias
CollaborationHigh precision design Krakow2006
Fast detector simulation – resolution
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
How does the LumiCal performancecontribute to the detector
displacements?
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
Adding detector performance
Using bias and resolution of Pad design LumiCal
without
Including
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
Adding detector performance
Using bias and resolution of Pad design LumiCal
without
Including
Data and MCIn real life we can include the detector performance (which is measured in test beam) into MC. The only question is: How well should we know the detector performance ?
CollaborationHigh precision design Krakow2006
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006
Test case: 20 mrad X-angle, LumiCal sits on detector axis
Unknown beam offset (amount, angle)
Simulation includes detector radius resolution and bias (Pad LumiCal)
Other parameters known
What will be the error on luminosity after using MC to correct DATA ?
Exercise
Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
N1
N2
N3
N4
X (cm)
Y (
cm)
20mrad X-angle Detector axis
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
Eve
nts
(up
– do
wn)
Events (right – left)
1 mm beam shift
0.5 mm beam shift
0.3 mm beam shift
Calibration
y = 5E-05x + 0.0008
0
0.02
0.04
0.06
0.08
0.1
0.12
05001000150020002500
Events
Bea
m s
hif
t (c
m)
“Beam position”
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
20mrad X-angle Detector axis
Before correction
after correction
ΔL/L~10-2
ΔL/L~10-3
But !!!!!!
This is assuming knowing in perfect
precision many parameters
Events per year
0.E+00
1.E+09
2.E+09
3.E+09
4.E+09
5.E+09
6.E+09
8 9 10 11 12 13 14 15 16
R min (cm)
Bha
bha
even
ts p
er y
ear
CollaborationHigh precision design Krakow2006
Tel Aviv University HEP Experimental Group
Collaboration
High precision design
Summary
Krakow2006
Our recommendation
at ECFA2005 still holds
Tel Aviv University HEP Experimental Group
Collaboration
High precision design
Beam hole
BeamCal
rmin=1.5 cm
rmax=10 cm
LumiCal
rmin=8 cm
rmax=28 cm
Head-on design
Overlap region
Krakow2006 Tel Aviv University HEP Experimental Group
Collaboration
High precision design
X- angle design (step 1)
Beam hole
BeamCal
rmin=2 cm
rmax=16 cm
LumiCal
rmin=13 cm
rmax=28 cm
(Reasonable Statistics)
Krakow2006 Tel Aviv University HEP Experimental Group
Collaboration
High precision design
BeamCal
+ 30o blind area
(incoming beam)
Detectors are centered around the
outgoing beam
X- angle design (step-2)
Krakow2006 Tel Aviv University HEP Experimental Group
Collaboration
High precision design Krakow2006 Tel Aviv University HEP Experimental Group
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