physics opportunities with future proton accelerators report to neutrino ids john ellis, march 29th...
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Physics Opportunities with Future Proton Accelerators
Report to Neutrino IDSJohn Ellis, March 29th 2007
POFPA study group:Blondel, Camilleri, Ceccucci, JE, Lindroos, Mangano, Rolandi
Advisory group to the CERN DG
The High-Energy Frontier @ CERN
• Context for our approach to high-intensity, lower-energy proton accelerators
• Need to maintain, refurbish CERN’s 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
European Strategy for Particle Physics
• Highest priority is to fully exploit the potential of the LHC: nominal performance and possible luminosity upgrade (SLHC) ~ 2015
• R&D on CLIC, high-field magnets, high-intensity neutrino facility
• Participation in ILC R&D, 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
Possible LHC Upgrade Options
• Upgrade of Linac– More intense beam @ 160 MeV: Linac4?
• Superconducting Proton Linac– Up to few MW @ few GeV: SPL?
• Replace PS– New medium-energy injector: PS2?
• Replace SPS– By SC machine @ 1 TeV: SPS+?
• New LHC insertions:– Luminosity 1035 cm-2s-1
PSB SPL’RCPSB
SPSSPS+
Linac4
SPL
RCPSPS
LHCDLHC
Out
put
ener
gy
160 MeV
1.4 GeV4 - 5 GeV
26 GeV40 – 60 GeV
450 GeV
1 TeV
7 TeV
~ 14 TeV
Linac250 MeV
DL
One Possible Scenario for Proton Injectors
PS2
L1, L2SL, DLB, Fk, , NP
SL, DLB, Fk, , NP
SL, DLB,Fk,
L1, L2SL, DLB,k,
SL, DLBk,
L1, L2SL, DL
L1
L1, L2SL, DLBk,
L1, L2
SL
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)
SL, DLBFk, NP
Proton flux / Beam power
L1, L2
Ultimate beam from SPS
PSB & PS replaced
SL ++
DL ++
B +++ (>100)
F +++ (~5 GeV prod. beam)
k, x00 kW beam at 50 GeV
NP +++
Layout of the new LHC Injectors
SPS
PS2
SPL
Linac4PS
New Physics @ SLHC
Measure triple-Higgs-boson
coupling with accuracy
comparable to 0.5 TeV LC
Measure triple-gauge-boson
coupling with accuracy
comparable to radiative corrections
Examples of Searches for New Physics
Extended reach for supersymmetry and a Z’ boson
SLHC Physics Reach Compared
Additional LHC Remarks• Reducing β* and minimizing the downtime are both
desirable.• The interaction regions for the SLHC have yet to be
defined– Need significant R&D for focusing magnets, etc.
– Layout may have significant implications for the experiments
• Bunch spacing 25 or 50ns?– 25ns would require machine elements @ 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
Upgrade Scenarios Currently Favoured
- Avoid problems with beam heating
- Peak luminosity ~ 1035 cm-2s-1
Detector Issues for the SLHCHigh radiation in central tracker
Congested layout in forward direction:
space for new low-β* machine elements?
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
The High-Intensity Frontier
• Exploration and understandingNovel phenomenaRare processesHigh statistics
• Active option in front-line physics: factories forZ, B, τ/Charm, K, antiproton, anti-Hydrogen
• Proton driver new opportunities for ν, muon, kaon, heavy-ion, nuclear physics
Neutrino Oscillation Physics
• Programme of precision neutrino oscillation physics, leading to discovery of CP violation, is an important, exciting, high-level goal
• If sin2θ13 > 10-2, may be possible to measure δ using superbeam/β beam + megaton water Cerenkov detector
• Neutrino factory with one or two distant detectors at very long baselines may be needed to measure δ if sin2θ13 < 10-3
• Analysis is one goal of International Scoping Study
ν Oscillation Facilities @ CERN
• CNGS:ν beam from SPS: τ production
• Superbeam?intense ν beam from SPL
• β beam?signed electron (anti) ν beams from heavy ions
• ν factory?muon and electron (anti) ν beams from μ decay
CERN Neutrino Beam to Gran Sasso
GeV 20E í ≈
Optimized for τ detectionCivil works completedCommissioned in 2006Physics in 2007?Intensity upgrade under study
Fluxes from Different ν Facilities
Superbeam
J-PARC
β beam
ν factory
NuMI
How to measure δ ? Error in δ as
function of θ13
SPL + β-beam sufficient if θ13 large,
need ν factory if θ13 small How soon will we know size of θ13?
Key information from Double-Chooz/T2K
Neutrinos as Probes of Standard Model
• Enormous interaction rates in nearby detector• Extraction of αs, sin2 ϑW
• Quark and antiquark densitiesPolarized and unpolarizede.g., strange quarks
• Charm production• Polarization of Λ baryons
also probe of strange polarization
Potential Accuracy for sin2θW
Measuring Strange Partons
Strange + antistrange Strange - antistrange
Muon Physics
• Proton source produces many muons• Rare μ decays
μ e γ, 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
μ eγ in Supersymmetric Seesaw
Many models predict μ eγ
close to present experimental limit,e.g., model where sneutrino responsible
for inflation, baryogenesis
Measuring SUSY Seesaw Parameters
9 measurable in ν physicsmi, θij, Majorana phases
18 parameters in total
12 Generate baryon asymmetry? 16 measurable in μ, τ decays, …
Comparing μ → eγ and μ → 3e μ → eγ above
experimental limit for generic parameter values
μ → 3e also suppressed for these parameter choices
μ → eγ suppressed for some parameter choices
μ → 3e: T-violating asymmetry AT
Enhanced when μ → eγ suppressed: interference between γ exchange and other diagrams
→ CP, T violation observable
Anomalous Magnetic Moment
‘Consensus’ on discrepancy withStandard Model, based on e+e- data
‘Natural’ supersymmetricinterpretation
Deserves a follow-up experiment
K → πνν: Searches beyond Standard Model
P-326 proposal for K+ → π+νν @ CERN
aims at 80 events -
could reach 1000 events with 4 MW @ 50 GeV
Potential impacts of K → πνν
measurements @ CERN
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.
Physics withRadioactiveNuclearBeams
Extremenuclei
Astrophysics
Particlephysics
Possible EURISOL Site @ CERN
• 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
POFPA dixit …
Blondel et al: hep-ph/0609102
POFPA dixit … redux
• We consider providing Europe with a forefront neutrino oscillation facility to be the next priority for CERN’s 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. … R&D is needed on a range of different detector technologies suited for different neutrino sources
Blondel et al: hep-ph/0609102
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 CERN’s 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
PAF dixit: Benefits for Physics