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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.

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The Linear Collider: a UK perspective

Grahame A. Blair

Edinburgh, 8th 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


Damping Rings

Beam Delivery System

Main Linac (RF)

Particle Sources

Generic Linear Collider

< ~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+

Schulte

  • Increase in luminosity (×~2)

  • Beamstrahlung  Lumi. Spectrum


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

Cross section

(pb)

Mtop=175 GeV

100 fb-1 per point

Statistical

Precision

~0.05 GeV

0.02%

Etot(GeV)

Martinez et al.


e-R

e+L

e-R

e-R

R

R

Initial State

  • W-production suppressed

  • s-wave production of charginos ~  sharp threshold

  • Specific polarisations for specific couplings (eg SUSY)

http://www.ippp.dur.ac.uk/~gudrid/power/

  • s-wave production of selectrons ~  sharp threshold

  • Direct production of higgs


Worldwide LC Studies

http://blueox.uoregon.edu/~lc/wwstudy/

http://blueox.uoregon.edu/~lc/alcpg/

http://acfahep.kek.jp/


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/


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 IP

It is possible that 1 IP will become the baseline –

The physics community needs to make its case clear

Adapted from Y. Kokoya, GDE Frascati 2005


SID

  • Design philosophy

  • Aim for SiW calorimeter

  • with 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


LDC

  • Design philosophy

  • Fine resolution calorimeter for particle

  • flow

  • Gaseous tracking for

  • High tracking efficiency

  • and redundancy

  • Large enough radius

  • and high enough B-field

  • (B=4 T) to get required

  • momentum resolution


GLD

  • Design philosophy

  • Large radius for particle-flow optimisation

  • Gaseous tracking for

  • High tracking efficiency

  • and redundancy

  • Fine grained scintillator-tungsten calorimeter

  • Moderate B-field (3 T)


Energy Flow in Jets

Some processes where WW and ZZ need to be separated without beam constraints.

Requires ΔE/E~30%/E


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/RHUL

Cockroft: 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


~3km

Beam Delivery System

  • Full simulations

  • Backgrounds

  • Optimisation

  • Precision Diagnostics

  • Energy

  • Polarisation

  • Luminosity


2 mrad Optics Design

  • 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

O.Napoly, 1997

QF1

pocket coil quad : C. Spencer

D. Angal-Kalinin


BDSIM

Beamlines are built

of modular

accelerator

components

Full simulation

of em showers

All secondaries

tracked

Screenshot of an IR Design in BDSIM


BDS: Muon Trajectories

Concrete tunnel 2m radius

BDS

View from top


Multi-Seed Luminosity Studies with the ILC Simulation Model

LUMI Feedback Optimisation (Position + Angle)

350 GeV CME

ANG + IP Fast Feedback

500 GeV CME

G. White


FONT3 installation on ATF beamline

BPM processor board

FEATHER

kicker

Amplifier/FB board

ATF beamline installation

June 05

P. Burrows


Bunch-Bunch Interaction Simulations

TESLA parameters

PINIT=1.0

low Q parameters

PINIT=1.0

Before interaction

During interaction

After interaction


Laser-wire: Principle


Laserwire - PETRA

+ UCL

11.2.05

System recently upgraded


ATF-LW Vacuum Chamber

Built at

Oxford

DO +

Workshop

Vacuum

Tested

At DL


Superconducting Helical Undulator

Parameters

Superconducting bifilar helix

First (20 period) prototype constructed (RAL)

Cut-away showing winding geometry


Wakefields

Change in beamline aperture

θ

  • 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

1500mm

ESA sz ~ 300mm – ILC nominal

sy ~ 100mm (Frank/Deepa design)

Magnet mover, y range = 1.4mm, precision = 1mm

N. Watson


38 mm

h=38 mm

L=1000 mm

a

r=1/2 gap

As per last set in Sector 2, commissioning

Extend last set, smaller r, resistive WF in Cu

7mm

cf. same r, tapered


Overview of LC Projects

Essentially independent of Linac-technology


2005 2006 2007 2008 2009 2010

Global Design Effort

Project

Baseline configuration

Reference Design

Funding

The GDE Plan and Schedule

Technical Design

globally coordinated

regionial coord

ILC R&D Program

expression of interest

Siting

Hosting

sample sites

FALC

International Mgmt

ICFA / ILCSC


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

  • excitation

  • curve

  • determine

    spin

TESLA TDR

20 fb-1 per point


Higgs Mass

mh=120 GeV

TESLA TDR

mh=150 GeV

500 fb-1 at √s=350 GeV


+

-

Higgs Recoil Mass

h

Z

Etot= 2 Ebeam

Ptot = 0

500 fb-1, √s=350 GeV

TESLA TDR


Higgs Mass Precision

500 fb-1, √s=350 GeV


Higgs Branching Ratios

For mh=120 GeV

Battaglia


Higgs Potential

λ/λ=0.22 (statistical) for mh=120 GeV

Requires 1000 fb-1

Muehleittner et al.


Supersymmetry


Supersymmetry

To prove existence of SUSY:

  • 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

Needs accurate measurements of

Mass spectra, cross-sections, BRs,

Angular distributions, polarisation


√s=1TeV

√s=500 GeV

Higgs gauginos sleptons squarks

SUSY Reference Points

Work with Sugra SPS1a:

M1/2=250 GeV M0=100 GeV

A0=-100 GeV sign()=+ tan=10


100 fb-1

Mass Measurements

Threshold scans

chargino ~ 

slepton ~ 3

Martyn et al.


Endpoint Measurements

√s=400 GeV

L=200 fb-1

 Both

sparticle masses

Martyn


e-e- running

Including width effects

m~50 MeV for 4 fb-1

Freitas, Miller, Zerwas

Feng, Peskin


Luminosity Budget

Grannis et al.

  • Several running modes required.

  • Input will already exist from LHC


Model-Independent Extrapolation

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: gaugino

Mi-1

GeV

Porod, Zerwas, GB


Mi2

Q (GeV)

Extrapolations mass terms

mSUGRA

structure

reconstructed

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

LHC

WMAP

Cosmology

links

LC

Trodden, Birkedal

LCWS04 (Adapted)


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!


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