Drive Beam generation with collector ring

1
Arnaud Ferrari (Uppsala University) Charged
and neutral Higgs bosons production at the
(future) multi-TeV ee- CLIC collider.

• CONTENTS
• General description of the CLIC project
• Challenges and RD program
• The CLIC physics case
• Charged and neutral Higgs bosons at CLIC

2
PART I GENERAL DESCRIPTION OF THE CLIC PROJECT
3
BASIC FEATURES OF CLIC

• Modular design, can be built in stages

4
CLIC TWO-BEAM SCHEME
The RF power is extracted from a secondary,
low-energy and high-intensity electron beam
running parallel to the main linac. There are no
active components such as modulators or
klystrons. Both linacs can be housed in a single
tunnel, on a common concrete base.
Drive beam - 150 A, 130 ns from 1.2 GeV to 200 MeV
Main beam - 1 A, 100 ns from 9 GeV to 1.5 TeV
5
(No Transcript)
6
CLIC RF POWER SOURCE LAYOUT
Gap creation, pulse compression and frequency
multiplication by 2
Pulse compression and frequency multiplication by
4
Pulse compression and frequency multiplication by
4
Return arc Bunch compression
7
HOW TO REACH HIGH LUMINOSITY AT CLIC?
Overall efficiency
Wall-plug power
Energy loss by beamstrahlung
Luminosity scaling
Centre-of-mass energy
Vertical normalized emittance
Nominal design centre-of-mass energy 3 TeV and
luminosity 1035 cm-2.s-1 ? Very small vertical
beam emittance small emittance growth during
acceleration ? Efficiency as high as possible
(about 10) ? Beamstrahlung energy loss for high
centre-of-mass energies
8
HIGH-ENERGY BEAM-BEAM EFFECTS AT CLIC
High beamstrahlung regime CLIC luminosity
spectrum at different centre-of-mass energies
Pair creation hard beamstrahlung photons can
turn into electron-positron pairs. About 6.8 108
coherent pairs are produced per bunch crossing
(it is comparable to the number of particles).
The detector can not be extended to very small
angles in order to remain out of the flux of
these particles, and it must also be protected
from most of their secondaries with a mask at
larger angles.
Hadronic background high-energy ?? collisions
produce four hadronic background events per bunch
crossing with a centre-of-mass energy above 5 GeV.
9
PART II CHALLENGES AND RD PROGRAM
10
MAIN CHALLENGES FOR CLIC

• Some of the CLIC challenges are common to all
  linear colliders accelerating gradient,
  generation and preservation of ultra-low
  emittances (damping rings), beam delivery and
  interaction point issues (alignment,
  backgrounds)
• Others are specific to the CLIC technology 30
  GHz components, efficient RF production with the
  two-beam acceleration technique
• CLIC technology-related key-issues to be
  addressed (rating given by ILC-TRC)
• R1 (feasibility demonstration)
• test of damped accelerating structures at design
  gradient and pulse length,
• validation of drive beam generation scheme with
  a fully-loaded linac,
• design and test of damped on/off power
  extraction structures.
• R2 (design finalisation)
• validation of beam stability and losses in the
  drive beam decelerator, and design of machine
  protection system
• test of relevant two-beam linac sub-unit.

All these R1 and R2 CLIC technology-related
key-issues will be addressed in the CLIC Test
Facility CTF3.
11
HIGH-GRADIENT TESTS IN CTF2
193 MV/m accelerating gradient in the first cell
(but only 16 ns pulse length).
12
THE CLIC TEST FACILITY CTF3
CTF3 test of drive beam-generation, fully-loaded
acceleration, pulse compression and bunch
frequency multiplication by a factor 10 with RF
deflectors, two-beam RF power generation and 30
GHz components tests with the nominal gradient
and pulse length (150 MV/m for 130 ns).
CERN Geneva (Switzerland) INFN Frascati
(Italy) LAL Orsay (France)
Northwestern University (USA) SLAC San Fransisco
(USA) Uppsala University (Sweden)
13
THE VARIOUS STAGES OF CTF3
14
R. Corsini, A. Ferrari, L. Rinolfi, P. Royer, and
F. Tecker, Experimental results on electron beam
combination and bunch frequency multiplication,
Phys. Rev. ST Accel. Beams 7, 040101 (2004).
THE CTF3 PRELIMINARY PHASE (2001-2002)
streak camera measurement
RF deflectors
low-charge demonstration of the electron pulse
compression and frequency multiplication
A
linac
15
THE UPPSALA BUNCH FREQUENCY MONITOR
Measure the power coming from the RF pick-up for
5 harmonics of interest (9, 12, 15, 18, 21 GHz)
during the bunch train combination.
Wakefieds are observed
During the bunch frequency multiplication by a
factor 4, the 12 GHz harmonics increases while
others tend to disappear.
16
COMMISSIONING OF THE CTF3 INITIAL PHASE IN 2003
INSTRUMENTATION (Screen Spectrometer)
ACS 3 4
ACS 1 2
Gun
INJECTOR
1ST LINAC MODULE
3RD MODULE (NO STRUCTURE)
MAGNETIC CHICANE AND SPECTROMETER
2ND MODULE (NO STRUCTURE)
The design beam parameters (3.5 A, 1.4 ?s) were
achieved, with a linac transport efficiency of
77.
Fully-loaded acceleration
Beam OFF
Output power from accelerating structure
Beam ON
17
PART III THE CLIC PHYSICS CASE
18
MOTIVATIONS FOR THE CLIC PHYSICS STUDIES

• The main motivation for most of the major new
  accelerators is experiments probing physics
  beyond the Standard Model.
• The first exploration of the TeV energy range
  will be made with LHC (and possibly a linear
  collider). One does not expect that it (they)
  will answer all questions concerning new physics
  beyond the Standard Model. For a complete
  coverage of this issue and full complementarity
  with LHC, a lepton-antilepton centre-of-mass
  energy of 2 TeV or more will be required.

• If particle masses are due to the Higgs
  mechanism, we want more information about the
  Higgs boson(s) than what LHC can tell us.
• If Nature chooses to replace an elementary Higgs
  boson by something new, then LHC will only
  provide hints and it should be followed by other
  experiments.
• If Nature is supersymmetric, then LHC will
  reveal a number of supersymmetric particles but
  not all of them.
• If new gauge bosons, extra dimensions, excited
  quarks or leptons etc are discovered at LHC, we
  will need to measure their properties more
  accurately.

19
HIGGS PHYSICS AT CLIC (1)
Understanding the origin of electroweak symmetry
breaking and mass generation will be the central
theme of high-energy physics research in the
coming decades. If a Standard Model Higgs boson
exists, it will be discovered at LHC, its mass
and a few of its couplings will be measured. A
TeV linear collider will provide the accuracy
needed to validate further the Higgs mechanism
and probe the nature of the Higgs sector
Standard Model or beyond?
CLIC offers a unique opportunity to probe even
further the Higgs sector by completing the light
Higgs boson profile 0.5106 decays of a Standard
Model Higgs boson per year!
20
HIGGS PHYSICS AT CLIC (2)
Higgs self-couplings and Higgs potential
Rare decays
mH (GeV) 240, 180, 140, 120
?g/g 4 _at_ mH 120 GeV
H ? ??
ee- ? HH?? is sensitive to triple-Higgs vertex
Heavy Higgs boson
?g/g 2 _at_ mH 180 GeV
ee- ? Hee- ? Xee-
Recoil mass analysis, clean signal up to 900 GeV
H ? bb
21
SUPERSYMMETRY AT CLIC
If Nature is supersymmetric, LHC will observe
part of the spectrum, and a TeV LC will then
measure accurately the kinematically accessible
states. CLIC will enable to complete the
supersymmetric spectrum and to measure precisely
the properties of sparticles that have been
discovered at LHC and LC (mass, mixing
angles). This allows to test unification
hypotheses for mechanisms of supersymmetry
breaking and even explore other scenarios with
R-parity violation.
22
PROBING NEW THEORIES AT CLIC (1)

• Beyond supersymmetry, there is a wide range of
  other scenarios with new phenomena at or beyond
  the TeV scale.
• explain the origin of electroweak symmetry
  breaking without a Higgs boson,
• stabilise the Standard Model if there is no
  supersymmetry,
• include the Standard Model in grand unification
  theories.

Gravity propagates in extra-dimensions while
gauge and matter fields are confined in a
3-dimensional brane. There are different
kinematical regimes (?s vs MD).
Extra dimensions
Production and evaporation of a black hole
Graviton Kaluza-Klein excitations in two-fermion
channels.
23
PROBING NEW THEORIES AT CLIC (2)
Extra-U(1) models can be tested very accurately
at CLIC. A new Z boson can be precisely measured
with a resonance scan (?m/m 0.005, ??/?
0.3, ??/? 0.3).
New vector resonances
Precision electroweak measurements in multi-TeV
ee- collisions for two-fermion production
cross-section or asymmetries will push the
indirect sensitivity to mass scales beyond 10 TeV.
Indirect sensitivity
strong WW scattering
Electroweak symmetry breaking with no Higgs boson
If no Higgs boson is found, one can expect the W
and Z bosons to develop strong interactions at
the TeV scale, leading to an excess of events and
even a resonance formation in the WW scattering.
And much more Little Higgs models, leptoquarks,
etc
24
PART IV CHARGED AND NEUTRAL HIGGS BOSONS AT
CLIC (LCWS 2004)