W. Morse May 15, 2007 1
Colliding 5nm Beams at the International Linear Collider
William MorseBrookhaven National Lab
W. Morse May 15, 2007 2
Outline of the Talk• International Linear Collider• See: “Physics Opportunities with a TeV Linear
Collider”, Sally Dawson and Mark Oreglia, Ann. Rev. Nucl. Part. Sci. 54:269 (2004),
• “Linear Collider Physics in the New Millennium”, A. Soni et al., World Sci. (2005)
• Colliding 5nm e+e- beams
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High Energy Colliders
Collider Particle Ecm (TeV)
Years Lum (cm-2s-1)
Tevatron(Fermi, US)
P-P+ 2 - 2009 1032
2 fb-1/syLHC
(CERN, SW)PP 14 2008 - 6 1033
120 fb-1
ILC (?) e+e- .5 - 1 2019 - 2 1034
200 fb-1
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Recent e+e- Colliders
Collider SLAC B(USA)
KEK B(Japan)
SLC(USA)
LEP 1-2(CERN)
Ecm
(TeV)
0.01 0.01 0.1polarized
0.1-0.2
Years - 2008 - ? - 1998 - 2000
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PDG:
ZprecisioncomesfromSLC/LEP
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Exploring the TeraVolt Scale• Protons are made up of quarks and gluons• Average quark or gluon carries 10% of the
proton’s energy• LHC: 1B uninteresting events/s, ie. need a
trigger• e+e- converts all the beam energy into the
collision energy• ILC: No uninteresting events/s, ie. no trigger!• Polarized electron positron beams• ILC dL/L 310-4 LHC dL/L 0.1
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JoAnne Hewett’s Slide
• Common feature of many models is a contact interaction type signature new gauge bosons,
large extra dimensions, compositeness, leptoquarks, string excitations, ….
-
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International Linear Collider• International from the start!• New paradigm for HEP• Global Design Effort of Asia, Europe, America• 2007 Reference Design Report – done!• 2009 Engineering Design Report• 2010 Tevatron/LHC Higgs physics results, ILC
site selection, International funding agreement ?• 2011-2018 Construction??• 2019 First Run ???
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Physics - Higgs Mechanism• Proposed by Peter Higgs almost fifty years ago• Spontaneous symmetry breaking to give particles mass• LEP direct search limit: MH>0.115TeV• Precision Electro-Weak Measurements at Tevatron
/LEP/SLC: MH < 0.2 TeV from virtual processes• Does nature give mass through Peter Higg’s
mechanism?• Only fundamental particle in the standard model with
spin zero!• Only particle in the standard model where the coupling
constant is proportional to mass.
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LHC2ILC Fermilab Apr 12-14• Reconstruct Higgs mass with collinear approximation
30 fb-1
H(ll) +2jets (VBF)
H(lh) +2jets (VBF)
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ILC with no trigger
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ILC can vary beam energy
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Hints of SUSY?
• BNL measurement of the anomalous magnetic moment of the muon (2004):
• aexp = 0.0011659208 (6)• aSM = 0.0011659179 (6)• SUSY theorists relieved!• asusy tan/M2
• 0.13TeV < Msusy < 0.47TeV• J. Miller, E. De Rafael, B. Roberts, hep-ph 0703049 (2007)
Review Article.
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D0 Z+Hbb Search
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Nominal ILC ParametersParameter ILC (0.5TeV) SLC (0.09TeV)
Luminosity 21034 cm-2s-1 21030 cm-2s-1
BX/s 15K .12K
y 5nm 500nm
x 500nm 1500nm
e/BX 21010 41010
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Feedback
• SLC found they needed feedback to optimize the luminosity with 1m beams – mainly beam position monitors (BPM).
• What detectors do we need to stabilize the beams at the 5nm level to achieve the design luminosity?
• 100V kicker.
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BNL Magnet Division Position Stability
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Achieving the ILC Luminosity Will Be a Challenge
• Bunch P- (t) {N, E, x, y, z, x, y, z, xy, x, y}• Bunch P+(t) {N, E, x, y, z, x, y, z, xy, x, y}• Beam motion >> 5nm!• Instantaneous Luminosity:
oy
ox
oo NNtL
)(
x
y
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Beam-strahlung Gammas
• F = e(E + cB)• E = 0, Bmax 1KT• P 3% Pe 0.4MW• N 1.5Ne 31010 /BX
mcFrP
32 220
yzx
xycNeB
0
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Beam-strahlung Pairs• Bethe-Heitler: e → e e+e-
BH 38 mb• <E> 1GeV• Landau-Lifshitz: ee → ee e+e-
LL 19 mb• <E> 0.15GeV• Breit-Wheeler: e+e-
BW 1 mb 104 e+e- /BX Maximum PT = 0.1 GeV/c
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Beam-strahlung Pairs
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Bethe-Heitler Pairs
e → e e+e-
oy
ox
oe
oBH
ee
NNN
oy
ox
oeBHee N
NN
oy
ox
oeee N
EE
For left and right detectors separately: N+/xy and N-/xy.
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Vertical offset
0
50
100
150
200
-200 -100 0 100 200
offset/2 (nm)
ener
gy in
gam
mas
(MTe
V)
0
5
10
gammas
pairs
E BeamCal (TeV)
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Vertical Offset
0
5
10
15
20
-200 -150 -100 -50 0 50 100 150 200
offset/2 (nm)
Lum
inos
ity (1
0^33
cm
^-2/
s)
0
0.05
0.1
Lum
R
R (10-6)
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Bunch Height
0
40
80
120
160
200
240
3 5 7 9 11
Bunch height (nm)
Energy
in gam
mas
(MTe
V)
0
4
8
12
16
gammas
pairs
02468
1012141618
3 5 7 9 11
Bunch height (nm)
Lum
inos
ity (1
0̂33
cm̂
-2/s)
0
0.02
0.04
0.06
0.08
Lum
R
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Bunch Length
0
50
100
150
200
250
300
350
150 200 250 300 350 400
Bunch Length (um)
gam
ma en
ergy
(MTe
V)
0
5
10
15
20
25
gammas
pairs
02468
1012141618
150 200 250 300 350 400
Bunch length (um)
Lum
(10̂
33 cm̂
-2/s)
0
0.02
0.04
0.06
0.08
Lum
R
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Forward Calorimeters
• LumiCal – forward Bhabhas for precision integrated luminosity measurement
• BeamCal – beam-strahlung pairs for instantaneous luminosity
• GamCal - beam-strahlung gammas for instantaneous luminosity
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International FCAL R&D Coll.
• W. Lohmann (DESY Zeuthen) spokesman• W. Morse (BNL) beam diagnostics
(BeamCal/GamCal) coordinator• B. Pawlik (Cracow) simulations coordinator• W. Lange (DESY) sensors coordinator• TBD electronics coordinator• W. Wierba (Cracow) LumiCal laser
alignment coordinator
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U.S. Forward (SiD)
• W. Morse (BNL): Coordinator• G. Haller, A. Abusleme, M. Breidenbach, D.
Freytag (SLAC): BeamCal readout design• Z. Li (BNL): BeamCal radiation damage issues• B. Parker (BNL): machine interface issues• M. Zeller, G. Atoian, V. Issakov, A. Poblaguev
(Yale): GamCal design• Y. Nosochkov (SLAC): Extraction line issues• U. Nauenberg (Colorado): SUSY studies
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BeamCal
• .003 < < .02 rad3.5m from IR• Measure the 104 beam-strahlung e+e-
pairs/BX for beam diagnostics• 2-10MGy/year• Beam diagnostics and hermeticity for
SUSY searches.
W. Morse May 15, 2007 37CollaborationHigh precision design DESY-PRC2006
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GamCal Detector 180m from IR 10-4 X0 to convert beam-strahlung gammas into
e+e- pairs• Converter could be gas jet or a thin solid
converter• Magnet to separate pairs from beam electrons! 3 1010 beamstrahlung gammas (2 GeV) 2 1010 beam electrons (0.2 TeV)• Evaluate the effect of beam electrons going
through conveter
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Beam-strahlung ZeeZ
0
5
10
15
20
0 1 2 3 4 5 6 7 8 9 10
E (GeV)
E dN
/dE
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GamCal Backgrounds
Gammas
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
-2 -1 0 1 2
log(E)
dN/d
log(
E)
BeamstBrem
1
10
100
1000
-2 -1 0 1 2log(E)
dN/d
log(
E) Delta RaysBeamst e
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ZeeZ vs. eZ eZee
• Electron carries virtual gammas• Landau Lifshitz conversion of virtual
gammas
211.1ln12
minbc
ddN
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Ratio of ZeeZ vs. eZ eZee
0
7
14
21
-1 0 1
log_10 (E)
Ratio
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Production Compared to ee
p eep 10 mbp N 0.5 mb in Δ resonance
regionp N 0.1 mb E > 4GeV• ep e N 10-3 mb • Thus ep e N is negligible
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Yale IBS Design
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Feed-back with Luminosity Detectors
P.N. Burrows GDE/MDI Vancouver 19/7/06
Intra-train y + y’ IP feedback simulations
0 100 200 300 400 500 6000
1
2
3x 10
34
Bunch #
Lum
inos
ity /
cm-2s-1
y position FB:restore collisionswithin 100 bunches
1 seed:
post-BBA
+ GM
+ wakes
y position scan:optimise signal in pair monitor
y angle scan
OPTIMALLUMINOSITY
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Conclusions
• We have designs for beam-strahlung pair and gamma detectors.
• Studies, simulations continuing.• Ratio of the beamstrahlung pairs
(BeamCal) to gammas (GamCal) is largely proportional to the instantaneous luminosity.
• Use feedback to bring 5nm beams into collision at maximum luminosity
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Extra Slides
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ILC Timeline
• Reference Design 2007• Engineering Design 2009• Site selection, LHC Physics results,
International Funding Agreement 2010• Construction Starts 2011• Construction Ends 2018• First Run 2019
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1 2
0
21
yE
0
21
yB
+ -
0
221
212
01
2
eyeyF
y
z
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Perfect Collisions
zx
NE 2
2
zyx
eeNE
3
3
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0
100
200
300
400
500
600
400 500 600 700 800 900
Bunch width (nm)
Ener
gy in
gam
mas
(MTe
V)O
0
10
20
30
40
50
60
gammas
pairs
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0
5
10
15
20
25
30
400 500 600 700 800 900
Bunch width (nm)
Lum
inos
ity (1
0^33
cm
^-2/
s)
0
0.02
0.04
0.06
0.08
0.1
0.12
Lum
R