Physics Opportunities with Future Proton Accelerators

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Physics Opportunities with Future Proton
Accelerators

• Report to Neutrino IDS
• John Ellis, March 29th 2007

POFPA study group Blondel, Camilleri, Ceccucci,
JE, Lindroos, Mangano, Rolandi Advisory group to
the CERN DG
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The High-Energy Frontier _at_ CERN

• Context for our approach to high-intensity,
  lower-energy proton accelerators
• Need to maintain, refurbish CERNs lower-energy
  accelerators (linac, booster, PS, SPS)
• Ambition to upgrade LHC luminosity by factor 10
  around 2015
• Requires upgrade of proton injector chain
• Look for possible synergies with other physics

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European Strategy for Particle Physics

• Highest priority is to fully exploit the
  potential of the LHC nominal performance and
  possible luminosity upgrade (SLHC) 2015
• RD on CLIC, high-field magnets, high-intensity
  neutrino facility
• Participation in ILC RD, decide 2010 (?)
• Prepare for neutrino facility decision 2012
• Non-accelerator physics
• Flavour and precision low-energy physics
• Interface with nuclear physics, fixed-target
  experiments

Topics for today
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Possible LHC Upgrade Options

• Upgrade of Linac
• More intense beam _at_ 160 MeV Linac4?
• Superconducting Proton Linac
• Up to few MW _at_ few GeV SPL?
• Replace PS
• New medium-energy injector PS2?
• Replace SPS
• By SC machine _at_ 1 TeV SPS?
• New LHC insertions
• Luminosity ? 1035 cm-2s-1

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One Possible Scenario for Proton Injectors

Proton flux / Beam power
L1
Linac2
L1, L2 SL, DL bB, nF k, m, NP
Linac4
50 MeV
160 MeV
SL, DL bB, nF k, m, NP
SL, DL bB, nF k, m, NP
PSB
SPL RCPSB
SPL
L1, L2 SL, DL
1.4 GeV
4 - 5 GeV
L1, L2 SL, DL bB, k, m
SL, DL bB, nF k, m
L1, L2
RCPS
PS
PS2
26 GeV
40 60 GeV
Output energy
L1, L2 SL, DL bB k, m
SPS
SL, DL bB k, m
SPS
SPL RCPSB injector (0.16 to 0.4-1 GeV) RCPSB
Rapid Cycling PSB (0.4-1 to 5 GeV) RCPS Rapid
Cycling PS (5 to 50 GeV) PS2 High Energy PS (5
to 50 GeV) SPS Superconducting SPS (50 to1000
GeV)
450 GeV
1 TeV
L1, L2 Ultimate beam from SPS PSB PS replaced
SL
DL
bB (g gt100)
nF (5 GeV prod. beam)
k, m x00 kW beam at 50 GeV
NP
LHC
SL
DLHC
DL
7 TeV
14 TeV
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Layout of the new LHC Injectors
SPS
PS2
SPL
PS
Linac4
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New Physics _at_ SLHC
Measure triple-gauge-boson coupling with
accuracy comparable to radiative corrections
Measure triple-Higgs-boson coupling with
accuracy comparable to 0.5 TeV LC
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Examples of Searches for New Physics
Extended reach for supersymmetry and a Z boson
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SLHC Physics Reach Compared
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Additional LHC Remarks

• Reducing ß and minimizing the downtime are both
  desirable.
• The interaction regions for the SLHC have yet to
  be defined
• Need significant RD for focusing magnets, etc.
• Layout may have significant implications for the
  experiments
• Bunch spacing 25 or 50ns?
• 25ns would require machine elements _at_ 3m from IP
• Shorter spacings have problems with heating of
  beam pipe
• Choice would have implications for injector chain
• Final choice of upgrade scenario will require
  global optimization of accelerator and detector
  expenses

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Upgrade Scenarios Currently Favoured

• - Avoid problems with beam heating
• - Peak luminosity 1035 cm-2s-1

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Detector Issues for the SLHC
High radiation in central tracker
Congested layout in forward direction space for
new low-ß machine elements?
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Final SLHC Remarks

• Definition of preferred LHC upgrade scenario in
  2010 will require some inputs from initial LHC
  operations
• E.g., neutron fluence, radiation damage and
  detector performance, as well as the early
  luminosity experience and physics results.
• Discussion of many possible scenarios for
  upgrading the LHC injector complex Linac4 ? SPS
• Common element in all LHC luminosity upgrade
  scenarios is Linac4 on critical path for
  optimizing the integrated LHC luminosity
• Roles for PS2, low-power SPL

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The High-Intensity Frontier

• Exploration and understanding
• Novel phenomena
• Rare processes
• High statistics
• Active option in front-line physics factories
  for
• Z, B, t/Charm, K, antiproton, anti-Hydrogen
• Proton driver ? new opportunities for
• ?, muon, kaon, heavy-ion, nuclear physics

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Neutrino Oscillation Physics

• Programme of precision neutrino oscillation
  physics, leading to discovery of CP violation, is
  an important, exciting, high-level goal
• If sin2?13 gt 10-2, may be possible to measure d
  using superbeam/ß beam megaton water Cerenkov
  detector
• Neutrino factory with one or two distant
  detectors at very long baselines may be needed to
  measure d if sin2?13 lt 10-3
• Analysis is one goal of International Scoping
  Study

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? Oscillation Facilities _at_ CERN

• CNGS
• ? beam from SPS t production
• Superbeam?
• intense ? beam from SPL
• ß beam?
• signed electron (anti) ? beams from heavy ions
• ? factory?
• muon and electron (anti) ? beams from µ decay

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CERN Neutrino Beam to Gran Sasso
Optimized for t detection Civil works
completed Commissioned in 2006 Physics in
2007? Intensity upgrade under study
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Fluxes from Different ? Facilities
NuMI
J-PARC
Superbeam
ß beam
? factory
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How to measure d ?
Error in d as function of ?13
Key information from Double-Chooz/T2K
SPL ß-beam sufficient if ?13 large, need ?
factory if ?13 small
How soon will we know size of ?13?
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Neutrinos as Probes of Standard Model

• Enormous interaction rates in nearby detector
• Extraction of as, sin2 ?W
• Quark and antiquark densities
• Polarized and unpolarized
• e.g., strange quarks
• Charm production
• Polarization of ? baryons
• also probe of strange polarization

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Potential Accuracy for sin2?W
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Measuring Strange Partons
Strange antistrange
Strange - antistrange
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Muon Physics

• Proton source produces many muons
• Rare µ decays
• µ ? e ?, µ ? eee,
• µ A ? e A
• Expected in susy seesaw model probe unknown
  parameters
• Dipole moments
• gµ 2, electric dipole moment, CPT tests
• Nuclear, condensed-matter physics
• (radioactive) µ-ic atoms, muonium, µ-ic Hydrogen

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µ ? e? in Supersymmetric Seesaw
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Measuring SUSY Seesaw Parameters
9 measurable in ? physics mi, ?ij, Majorana phases
18 parameters in total
12 Generate baryon asymmetry?
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Comparing µ ? e? and µ ? 3e
µ ? e? above experimental limit for generic
parameter values
µ ? 3e also suppressed for these parameter
choices
µ ? e? suppressed for some parameter choices
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µ ? 3e T-violating asymmetry AT
Enhanced when µ ? e? suppressed interference
between ? exchange and other diagrams ? CP, T
violation observable
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Anomalous Magnetic Moment
Consensus on discrepancy with Standard Model,
based on ee- data
Deserves a follow-up experiment
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K ? p?? Searches beyond Standard Model
P-326 proposal for K ? p?? _at_ CERN aims at 80
events - could reach 1000 events with 4 MW _at_ 50
GeV
Potential impacts of K ? p?? measurements _at_ CERN
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Isotope Source for Nuclear Physics

• The limits of nuclear existence
• neutron proton drip lines,
• superheavy elements,
• extreme nucleonic matter
• Nuclear astrophysics
• rp-process, r-process
• Probes of Standard Model
• CKM, P, T, CP
• Materials science
• radioactive spies, curing chemical blindness,
• positron annihilation studies,
• applications to biomedicine, etc.

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Physics with Radioactive Nuclear Beams
Particle physics
Extreme nuclei
Astrophysics
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Possible EURISOL Site _at_ CERN
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POFPA dixit

• We consider experimentation at the high-energy
  frontier to be the top priority in choosing a
  strategy for upgrading CERN's proton accelerator
  complex. This experimentation includes the
  upgrade to optimize the useful LHC luminosity
  integrated over the lifetime of the accelerator,
  through both a consolidation of the LHC injector
  chain and a possible luminosity upgrade project
  we term the SLHC
• The absolute and relative priorities of these and
  high-energy linear-collider options will depend,
  in particular, on the results from initial LHC
  runs, which should become available around 2010

Blondel et al hep-ph/0609102
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POFPA dixit redux

• We consider providing Europe with a forefront
  neutrino oscillation facility to be the next
  priority for CERNs proton accelerator complex,
  with the principal physics objective of observing
  CP or T violation in the lepton sector
• The most cost-effective way to do this either a
  combination of superbeam and ?-beam or a neutrino
  factory using stored muons will depend, in
  particular, on the advances to be made in
  neutrino oscillation studies over the next few
  years. RD is needed on a range of different
  detector technologies suited for different
  neutrino sources

Blondel et al hep-ph/0609102
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POFPA dixit redux2

• Continuing research on topics such as kaon
  physics, fixed-target physics with heavy ions,
  muon physics, other fixed-target physics and
  nuclear physics offers a cost-effective
  supplementary physics programme that would
  optimize the exploitation of CERNs proton
  accelerators.
• However, we consider that these topics should not
  define the proton accelerator upgrade scenario,
  but rather adapt to whichever might be preferred
  on the basis of the first two priorities.

Blondel et al hep-ph/0609102
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PAF dixit Benefits for Physics