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The Linear Collider: a UK perspective. Grahame A. Blair Edinburgh, 8 th February 2006. Introduction to the machine Detectors UIK activities Timescales Some key Physics (time ?) Summary. www.linearcollider.org. Superconducting Niobium Cavities. Y. Kokoya, GDE Frascati 2005. - PowerPoint PPT Presentation
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The Linear Collider: a UK perspective
• Introduction to the machine• Detectors• UIK activities• Timescales• Some key Physics (time ?)• Summary
Grahame A. BlairEdinburgh, 8th February 2006
www.linearcollider.org
Superconducting Niobium Cavities
Y. Kokoya, GDE Frascati 2005
Generic Linear Collider
Damping Rings
Particle Sources
Main Linac (RF)Beam Delivery System
< ~20 km > < ~4 km >
DR Circumf. Baseline: 6km
Damping Process
Y. Kokoya, GDE Frascati 2005
A Possible Layout
• Approximately follow earth’s curvature• Upgrade path to ~1 TeV
LC for Physics Purposes:
• e+e- collisions with √s tuneable 0.5 – O(1) TeV• e-e- mode.• Polarisation: e- 80% (L/R); e+ 60% (?).• Possibility to run at √s ~ 90 – 160 GeV (“GigaZ”)• Luminosity 3-6.1034 cm-2 s-1 specific
analyses can assume up to about 1 ab-1
Also possible/important; Compton scattering to
produce or e
Bunch Interactions
e+ e-
• Increase in luminosity (×~2)
• Beamstrahlung Lumi. Spectrum
Schulte
Luminosity Spectrum
• sharp peak• approx same as ISR (tuned) – few % in tail for 0.5-1 TeV machines
TESLA TDR
Precision Measurement of the Top Mass
Precision measurement of fundamental particle properties
The top quark is the heaviest: most sensitive to new physics
Etot(GeV)
Cross section (pb)
Statistical Precision ~0.05 GeV0.02%
Mtop=175 GeV100 fb-1 per
point
Martinez et al.
Initial State
e-R e+
L• W-production suppressed• s-wave production of charginos ~ sharp threshold• Specific polarisations for specific couplings (eg SUSY)
e-R e-
R• s-wave production of selectrons ~ sharp threshold
R R• Direct production of higgs
http://www.ippp.dur.ac.uk/~gudrid/power/
Worldwide LC Studies
http://blueox.uoregon.edu/~lc/wwstudy/
http://acfahep.kek.jp/
http://blueox.uoregon.edu/~lc/alcpg/
Worldwide studies (2)
http://www.desy.de/conferences/ecfa-lc-study.html
http://clicphysics.web.cern.ch/CLICphysics/
The Detectors
http://physics.uoregon.edu/~ lc/wwstudy/concepts/
Adapted from Y. Kokoya, GDE Frascati 2005
Number of IPs• 2 IPs + 2 detectors is the baseline.
• The cost of 2nd IP (beamline + exp.hall) corresponds to the energy 14-19% of 500GeV (change of tunnel cost not included).
Caveats: Total cost estimation from 3 regions agree well but the cost of individual components scatter in wide ranges.
• This means 405-430 GeV LC with 2IP is comparable in cost
with 500GeV LC with 1 IPIt is possible that 1 IP will become the baseline –The physics community needs to make its case clear
Design philosophy• Aim for SiW calorimeterwith best possible resolution• Keep radius small to make this affordable• Compensate by high B-field (5 T) and very precise tracking (Si)• Fast timing of Silicon to suppress background
SID
Design philosophy• Fine resolution calorimeter for particleflow• Gaseous tracking forHigh tracking efficiency and redundancy• Large enough radiusand high enough B-field(B=4 T) to get requiredmomentum resolution
LDC
Design philosophy• Large radius for particle-flow optimisation• Gaseous tracking forHigh tracking efficiency and redundancy• Fine grained scintillator-tungsten calorimeter• Moderate B-field (3 T)
GLD
Energy Flow in JetsSome processes where WW and ZZ need to be separated without beam constraints.
Requires ΔE/E~30%/E
EE
E %30
EE
E %30
S. Worm, LCUK meeting, Oct 05
Particle/Machine Physics
• The LC will be a very challenging machine• Particle physicists are taking part in
machine studies• Beam diagnostics and control• Background estimates• Design studies• The particle physics programme now goes
beyond “what comes out of the IP”.
UK funding for accelerator science for particle physics 2004 - 2007
UK funding agency, PPARC, secured from Govt. £11M for ‘accelerator science’ for particle physics, spend period April 04 – March 07
Called for bids from universities and national labs; large consortia were explicitly encouraged
LC-Beam Delivery £9.1M + 1.5M CCLRC UKNF £1.9M 2 university-based accelerator institutes: John Adams: Oxford/RHULCockroft: Liverpool, Manchester, Lancaster, NW dev. agency.
Funding period ends in 2007; new bid will be finalised in July 2006.
LC-ABD Collaboration
• Bristol • Birmingham • Cambridge• Dundee • Durham • Lancaster• Liverpool • Manchester • Oxford • QMUL• RHUL• University College, London • Daresbury and Rutherford-Appleton Labs;
41 post-doctoral physicists (faculty, staff, research associates) + technical staff + graduate students
UK Interests:Beam Delivery System
Beam Delivery System
~3km
Full simulations
BackgroundsOptimisationPrecision Diagnostics• Energy• Polarisation• Luminosity
Final Focus and extraction line optimized simultaneously Quadrupoles and sextupoles in the FD optimized to
cancel FF chromaticity focus the extracted beam
SLAC-BNL-UK-France Task Group
QF1
pocket coil quad : C. Spencer
O.Napoly, 1997
2 mrad Optics Design
D. Angal-Kalinin
BDSIMBeamlines are builtof modular accelerator components
Full simulationof em showers
All secondariestracked
Screenshot of an IR Design in BDSIM
BDS: Muon Trajectories
BDS
Concrete tunnel 2m radius
View from top
Multi-Seed Luminosity Studies with the ILC Simulation Model
1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.850
5
10
15
20
25
Luminosity / cm-2 s-1 1034
= 1.6747 0.067286
2.7 2.75 2.8 2.85 2.9 2.95 3 3.050
2
4
6
8
10
12
14
16
18
Luminosity / cm-2 s-1 1034
= 2.8788 0.075445
350 GeV CME
500 GeV CME
0 100 200 300 400 500 6000
1
2
3x 10
34
Bunch #
Lu
min
os
ity
/ c
m-2
s-1
ANG + IP Fast Feedback
LUMI Feedback Optimisation (Position +
Angle)
G. White
37
FONT3 installation on ATF beamline
BPM processor board
Amplifier/FB board
FEATHERkicker
ATF beamline installation June 05
P. Burrows
Bunch-Bunch Interaction Simulations
Before interaction During interaction After interaction
TESLA parameters
low Q parameters
PINIT=1.0
PINIT=1.0
Laser-wire: Principle
Laserwire - PETRA+ UCL
11.2.05
System recently upgraded
ATF-LW Vacuum Chamber
Built atOxfordDO +Workshop
VacuumTestedAt DL
Superconducting Helical Undulator
Superconducting bifilar helix
First (20 period) prototype constructed (RAL)
Design field 0.8 T
Period 14 mm
Magnet bore 4 mm
Winding bore 6 mm
Winding section 4 4 mm2
Overall current density 1000 A/mm2
Peak field (not on-axis) 1.8 T
Cut-away showing winding geometry
Parameters
Wakefields
θChange in beamline aperture
• Wake-fields from the head of the bunch can disturb the tail• Wake-fields from earlier bunches can disturb later ones• (such effects can also be useful – eg. Smith-Purcell radiation)
Wakefield box
ESA z ~ 300m – ILC nominaly ~ 100mm (Frank/Deepa design)
Magnet mover, y range = mm, precision = 1m
1500mm
N. Watson
Slot Side view Beam view
1
=324mrad
r=2.0mm
2
324mrad
r=1.4mm
3
324mrad
r=1.4mm
4
=/2rad
r=4.0mm
h=38 mm
38
mm
L=1000 mm
7mm
r=1/2 gap
As per last set in Sector 2, commissioningAs per last set in Sector 2, commissioning
Extend last set, smaller r, resistive WF in CuExtend last set, smaller r, resistive WF in Cu
cf. same r, taperedcf. same r, tapered
Lattice design + Simulation8%
Beam Transport + Backgrounds
9%
Laser-wire15%
Longitudinal Profile7%
Polarisation1%
LiCAS15%
FONT+ BPM Spectrometry17%
Polarised Positron Undulator
8%
Crab Cavity13%
Collimation5%
Training+ General2%
Overview of LC Projects
Essentially independent of Linac-technology
The GDE Plan and Schedule
2005 2006 2007 2008 2009 2010
Global Design Effort Project
globally coordinated
Baseline configuration
Reference Design
ILC R&D Program
Technical Design
FALC
Siting
International Mgmt
expression of interestsample sites
regionial coord
ICFA / ILCSC
Funding
Hosting
Machine Summary
• The ILC is now being defined.• The Baseline is under “Configuration Control”• Global Design Effort is in place, with a very
active programme aiming at a Reference Design Report at end of 2006.
• UK is involved in two detector projects and an exciting range of accelerator R&D.
• The next round of accelerator-related bids are due for this summer.
a great time to get involved.
ILC Physics:
Higgs Production
For Mh~120 GeV, 500 fb-1, √s=350 GeV
80,000 Higgs
TESLA TDR
Higgs Spin
Threshold excitationcurve
determine spin
20 fb-1 per pointTESLA TDR
Higgs Mass
mh=120 GeV mh=150 GeV
qqbbhZ 0 qqWWhZ 0
500 fb-1 at √s=350 GeV
TESLA TDR
Higgs Recoil Mass
h Z
+
-
Etot= 2 Ebeam
Ptot = 0
500 fb-1, √s=350 GeV
TESLA TDR
Higgs Mass PrecisionMh(GeV) Channel Mh (MeV)
120 llqq 70
120 qqbb 50
120 combined 40
150 ll recoil 90
150 qq WW 130
150 combined 70
180 ll recoil 100
180 qq WW 150
180 combined 80
500 fb-1, √s=350 GeV
Higgs Branching Ratios
h→ BR/BR
bb 0.024
cc 0.083
gg 0.055
ττ 0.050
For mh=120 GeV
Battaglia
Higgs Potential
4322
4
1hvhhvV
λ/λ=0.22 (statistical) for mh=120 GeVRequires 1000 fb-1
Muehleittner et al.
Supersymmetry
Supersymmetry
• Need to discover the SUSY partners
• Every SM has a superpartner
• Spins of SM/SUSY partner differ by ½
• Identical gauge quantum numbers
• Identical couplings
To prove existence of SUSY:
Needs accurate measurements of
Mass spectra, cross-sections, BRs,
Angular distributions, polarisation
SUSY Reference PointsWork with Sugra SPS1a:M1/2=250 GeV M0=100 GeVA0=-100 GeV sign()=+ tan=10
Higgs gauginos sleptons squarks
√s=500 GeV
√s=1TeV
Mass Measurements
Threshold scanschargino ~ slepton ~ 3
55.05.181 m
01
0111 LRee
100 fb-1
Martyn et al.
Endpoint Measurements
√s=400 GeVL=200 fb-1
Both sparticle masses
Martyn
e-e- running
Freitas, Miller, Zerwas
Feng, Peskin
Including width effects
m~50 MeV for 4 fb-1
Luminosity Budget
• Several running modes required.• Input will already exist from LHC
Grannis et al.
Model-Independent Extrapolation
,...),,( kjii gmPfQ
P
Renormalisation Group Eqns
•Measure complete spectrum•Extract soft SUSY parameters at EW scale•Input measured masses, couplings into RGEs•Extrapolate model independently to high scales
Extrapolation: gauginoMi
-1
GeVPorod, Zerwas, GB
Mi2
Q (GeV)
Extrapolations mass terms
mSUGRAstructurereconstructed
Fine structure?
GigaZ• The LC can also provide high luminosity running at the Z-pole and at W-threshold• Approximately 100 fb-1 per year• Needs specific linac bypass design
TESLA TDR
Concrete example - point B’ of “updated benchmark” points:
mSUGRA w/ tan = 10, sgn()=+1, m0=57, m1/2=250, A0=0
Trodden, Birkedal LCWS04 (Adapted)
WMAP
LC
LHC
Cosmologylinks
Physics Summary
• The linear collider will provide high precision measurements at high energy: Masses, chiral couplings, branching ratios…
• Together with LHC data, LC allows model-independent extrapolations to very high energy scales.
• Exciting overlap with LHC analyses complementary searches, constraints in cascades… see G.W talk
• Links to cosmology• Long term programme from O(1) TeV, GigaZ, ,
multi TeV.• An exciting time ahead!