Neutrino oscillation physics with superbeams and neutrino factories Nu HoRIzons workshop HRI, India February 13-15, 2008 Walter Winter Universität Würzburg

Feb. 14, 2008Nu HoRIzons Walter Winter2 Contents Introduction Introduction Superbeams Superbeams –What can we expect from 1 st generation experiments? –Examples for upgrade options Neutrino factory Neutrino factory –IDS-NF baseline setup 1.0 –Detector requirements/detector optimization –Physics with a very long baseline (to India?) –Requirements for non-standard measurements/ physics case for the silver channel? Summary and conclusions Summary and conclusions Will not talk about beta beams! Contents reflect a biased selection of aspects!

Feb. 14, 2008Nu HoRIzons Walter Winter3 Evolution of  13 discovery limit? Specific scenario Specific scenario Bands reflect dependence on  CP Bands reflect dependence on  CP (from: FNAL Proton Driver Study) GLoBES 2005 (NOvA)

Feb. 14, 2008Nu HoRIzons Walter Winter4 Appearance channels (Cervera et al. 2000; Freund, Huber, Lindner, 2000; Huber, Winter, 2003; Akhmedov et al, 2004) Antineutrinos: Antineutrinos: Magic baseline: Magic baseline: Silver: Silver: Platinum: Platinum:

Feb. 14, 2008Nu HoRIzons Walter Winter5 Superbeams: Concept Conventional neutrino beams: Neutrino production by pion, kaon decays (obtained from protons hitting a target) Conventional neutrino beams: Neutrino production by pion, kaon decays (obtained from protons hitting a target) „Super“-beams: T2K, NOvA „Super“-beams: T2K, NOvA –Higher target powers O(1 MW) –Larger detectors O(30 kt) –Off-axis technology (for BG suppression, lower E) „Super“-Superbeams, superbeam upgrades: WBB, T2KK, CERN- Memphys, NuMI*, … „Super“-Superbeams, superbeam upgrades: WBB, T2KK, CERN- Memphys, NuMI*, … –Even higher target powers O(4 MW) –Even larger detectors O( kt) –On- or off-axis technology –„Super“ pricy For leading atm. params Signal prop. sin 2 2  13 Contamination

Feb. 14, 2008Nu HoRIzons Walter Winter6 Running example for beams: MINOS Measurement of atmospheric parameters with high precision Measurement of atmospheric parameters with high precision Flavor conversion ? Flavor conversion ? Fermilab - Soudan L ~ 735 km Far detector: 5400 t Near detector: 980 t 735 km Beam line

Feb. 14, 2008Nu HoRIzons Walter Winter7 Perspectives for MH and  CP for the coming 5 to 10 years? A mass hierarchy or CP violation measurement will be unlikely or impossible from A mass hierarchy or CP violation measurement will be unlikely or impossible from –Beams+Reactor experiments –Any other source alone (supernova etc.) (from: Huber, Lindner, Rolinec, Schwetz, Winter, 2004)

Feb. 14, 2008Nu HoRIzons Walter Winter8 Superbeam upgrades: Examples Exposure: Detector mass [Mt] x Target power [MW] x Running time [10 7 s] Exposure: Detector mass [Mt] x Target power [MW] x Running time [10 7 s] Bands: variation of systematical errors: 2%-5%-10% Bands: variation of systematical errors: 2%-5%-10% Dots: Nominal L Dots: Nominal L Typical  CP, 3  Typical  CP, 3  (Barger, Huber, Marfatia, Winter, hep-ph/ , hep-ph/ ) discovery

Feb. 14, Luminosity scalings If  13 found by superbeams: If  13 found by superbeams: –WBB and T2KK can measure CPV, MH –NuMI requires Lumi-upgrade (ProjectX?) Systematics impact least for WBB; best physics concept? Systematics impact least for WBB; best physics concept?

Feb. 14, 2008Nu HoRIzons Walter Winter10 Baseline-OA-Optimization Example: NuMI-like beam  100kt liquid argon  CP =-  /2  CP =+  /2 sin 2 2   CP violationMass hierarchy (Barger, Huber, Marfatia, Winter, 2007) Constraint from NuMI beam FNAL- DUSEL WBB Ash River OA, NOvA*

Feb. 14, 2008Nu HoRIzons Walter Winter11 Large  13 case … for the sensitivity to CP violation Superbeam upgrades can easily outperform a „straightforward“ NF Superbeam upgrades can easily outperform a „straightforward“ NF How can one optimize a neutrino factory for large  13 ? How can one optimize a neutrino factory for large  13 ? (Barger, Huber, Marfatia, Winter, hep-ph/ )  =350 beta beam Burguet-Castell et al, 2005 Neutrino factory km 50 kt + 50 kt NuMI beam to 100kt LArTPC FNAL - DUSEL 100kt LArTPC 270kt+270kt WC detector

Feb. 14, Neutrino factory Ultimate “high precision” instrument!? Ultimate “high precision” instrument!? Muons decay in straight sections of storage ring Muons decay in straight sections of storage ring Technical challenges: Target power, muon cooling, charge identification, maybe steep decay tunnels Technical challenges: Target power, muon cooling, charge identification, maybe steep decay tunnels For leading atm. params Signal prop. sin 2 2  13 Contamination ISS (Geer, 1997; de Rujula, Gavela, Hernandez, 1998; Cervera et al, 2000)

Feb. 14, 2008Nu HoRIzons Walter Winter13 NF optimization potential (ISS) Optimized NuFact: Excellent  13 reach for both MH and CPV Optimized NuFact: Excellent  13 reach for both MH and CPV But: For sin 2 2  13 ~ 10 -2,  =350 beta beam (L=730 km) better But: For sin 2 2  13 ~ 10 -2,  =350 beta beam (L=730 km) better 33 (Huber, Lindner, Rolinec, Winter, hep-ph/ ;  -beam: Burguet-Castell et al, hep-ph/ ) E  =50 GeV E  =20 GeV

Feb. 14, 2008Nu HoRIzons Walter Winter14 IDS-NF launched at NuFact 07 International design study for a neutrino factory Successor of the International Scoping Study for a „future neutrino factory and superbeam facility“: Physics case made in physics WG report (~368 pp) (arXiv: [hep.ph]) Successor of the International Scoping Study for a „future neutrino factory and superbeam facility“: Physics case made in physics WG report (~368 pp) (arXiv: [hep.ph]) Initiative from ~ to present a design report, schedule, cost estimate, risk assessment for a neutrino factory Initiative from ~ to present a design report, schedule, cost estimate, risk assessment for a neutrino factory In Europe: Close connection to „Euro us“ proposal within the FP 07; currently ranked #1, negotiating contract In Europe: Close connection to „Euro us“ proposal within the FP 07; currently ranked #1, negotiating contract In the US: „Muon collider task force“ How can a neutrino factory be „upgraded“ to a muon collider? In the US: „Muon collider task force“ How can a neutrino factory be „upgraded“ to a muon collider?

Feb. 14, 2008Nu HoRIzons Walter Winter15 IDS-NF baseline setup 1.0 Two decay rings Two decay rings E  =25 GeV E  =25 GeV 5x10 20 useful muon decays per baseline (both polarities!) 5x10 20 useful muon decays per baseline (both polarities!) Two baselines: ~ km Two baselines: ~ km Two MIND, 50kt each Two MIND, 50kt each Currently: MECC at shorter baseline Currently: MECC at shorter baseline (

Feb. 14, 2008Nu HoRIzons Walter Winter16 IDS-NF baseline setup 1.0 description 55% E 0.5 energy resolution 55% E 0.5 energy resolution Detection threshold and backgrounds from new simulation Detection threshold and backgrounds from new simulation 2.5% signal uncertainty, 20% BG uncertainty 2.5% signal uncertainty, 20% BG uncertainty 5 yr + 5 yr running time 5 yr + 5 yr running time Silver channel: 10 kt Silver from hep-ph/ (Autiero et al MECC) Silver channel: 10 kt Silver from hep-ph/ (Autiero et al MECC) (IDS-NF baseline specification) Old analysis/det. Baseline detector New analysis (diff. L  )

Feb. 14, 2008Nu HoRIzons Walter Winter17 IDS baseline performance for discovery … evaluated with GLoBES! 33

Feb. 14, 2008Nu HoRIzons Walter Winter18 Two-baseline optimization revisited Sensitivity for all sin 2 2  13 > (  13 ), sin 2 2  13 > (MH, CPV) (5  ) for the shown performance indicator Sensitivity for all sin 2 2  13 > (  13 ), sin 2 2  13 > (MH, CPV) (5  ) for the shown performance indicator True  CP chosen close to worst case True  CP chosen close to worst case Robust optimum for ~ km Robust optimum for ~ km (Kopp, Ota, Winter, in prep.) IDS baseline Optimum

Feb. 14, 2008Nu HoRIzons Walter Winter19 Consequences for detector locations Long baseline: L ~ km good choice: Long baseline: L ~ km good choice: CERN-INO?

Feb. 14, 2008Nu HoRIzons Walter Winter20 Magic baseline - detector requirements IDS-NF baseline requires two MINDs as specified IDS-NF baseline requires two MINDs as specified What if What if –The long baseline detector is smaller? –The CID capabilities do not allow for the specified threshold/backgrounds? Quality more important than quantity!

Feb. 14, 2008Nu HoRIzons Walter Winter21 Large  13 : Low-E (low budget?) NuFact Use magnetized detector with low threshold to allow for lower E   (Bross, Ellis, Geer, Mena, Pascoli, 2007) Use magnetized detector with low threshold to allow for lower E   (Bross, Ellis, Geer, Mena, Pascoli, 2007) Combine with superbeam? – NF-Superbeam: Combine with superbeam? – NF-Superbeam: (Huber, Winter, 2007) Or use second target? *

Feb. 14, 2008Nu HoRIzons Walter Winter22 Low-E NuFact: CPV comparison NF-SB (E p =28 GeV, E  =5 GeV, L=1250 km) can outperform any of the discussed setups except from beta beam NF-SB (E p =28 GeV, E  =5 GeV, L=1250 km) can outperform any of the discussed setups except from beta beam But: Luminosity choice for beta beam arbitrary in this context! Parameters:  =350, L=712 km, 5 yr x useful 6 He decays/yr, 5 yr x useful 18 Ne decays/yr (Burguet-Castell et al, 2005) But: Luminosity choice for beta beam arbitrary in this context! Parameters:  =350, L=712 km, 5 yr x useful 6 He decays/yr, 5 yr x useful 18 Ne decays/yr (Burguet-Castell et al, 2005) (Huber, Winter, 2007) E p =28 GeV 500 kt WC

Physics with a very long neutrino factory baseline CERN-INO???

Feb. 14, 2008Nu HoRIzons Walter Winter24 Precision measurements (Gandhi, Winter, 2006)(Huber, Lindner, Winter, 2004)  CP precision  13 precision  CP dep. 33

Feb. 14, 2008Nu HoRIzons Walter Winter25 Further applications: Matter density measurement Idea: Treat  as yet another oscillation parameter to be measured; marginalize oscillation parameters! Idea: Treat  as yet another oscillation parameter to be measured; marginalize oscillation parameters! Comes „for free“ from very long baseline!? Comes „for free“ from very long baseline!? Two different models: Two different models: 1.Measure  Ref 2.Measure  LM (lower mantle density) (Winter, 2005; Minakata, Uchinami, 2006; Gandhi, Winter, 2006) Lower mantle density

Feb. 14, 2008Nu HoRIzons Walter Winter26 Matter density: Geophysical use? Example: Plume hypothesis Example: Plume hypothesis A precision measurement << 1% could discriminate different geophysical models A precision measurement << 1% could discriminate different geophysical models  Possible selector of detector locations? (Courtillot et al., 2003; see talk from B. Romanowicz, Neutrino geophysics 2005)

Feb. 14, 2008Nu HoRIzons Walter Winter27 Results for one-parameter measurement Assume that only one parameter measured Assume that only one parameter measured For large  13, < 1% precision at 3  For large  13, < 1% precision at 3  Indep. confirmed by Minakata, Uchinami (for one baseline) Indep. confirmed by Minakata, Uchinami (for one baseline) (Gandhi, Winter, 2006) True  =0

Feb. 14, 2008Nu HoRIzons Walter Winter28 Resolving the  23 degeneracy 4000 km alone: Problems with degs for intermediate  km alone: Problems with degs for intermediate  km alone: No sensitivity for small  km alone: No sensitivity for small  km km: Good for all  km km: Good for all  13 (Gandhi, Winter, 2006) Similar performance to 4000km Meloni, arXiv:

Feb. 14, 2008Nu HoRIzons Walter Winter29 Solar term: Note that i.e., effect increases with baseline (  ~ L)! Solar term: Note that i.e., effect increases with baseline (  ~ L)! MSW effect sensitivity: even for  13 =0! (Winter, 2004) 55

Requirements for new physics searches?

Feb. 14, 2008Nu HoRIzons Walter Winter31 Non-standard neutrino interactions Consider effective four-point interactions Consider effective four-point interactions This leads to a Hamiltonian for propagation: matter potential: This leads to a Hamiltonian for propagation: matter potential: For antineutrinos: H  H*, a CC  -a CC For antineutrinos: H  H*, a CC  -a CC Weak constraints

Feb. 14, 2008Nu HoRIzons Walter Winter32 NSI with magic baseline Combing the two baselines reduces the impact of correlations drastically (only real  e  assumed!) Combing the two baselines reduces the impact of correlations drastically (only real  e  assumed!) Does one still need the silver channel in that case? Does one still need the silver channel in that case? 3000 km 7000 km Combined arXiv: Close to worst case for degeneracies:  CP =3  /2, sin 2 2  13 = Disappearance (Kopp, Ota, Winter, in prep)

Feb. 14, 2008Nu HoRIzons Walter Winter33 Correlations at magic baseline Including NSI, the magic baseline is not exactly correlation/degeneracy-free Including NSI, the magic baseline is not exactly correlation/degeneracy-free Example: High-E Approximation Example: High-E Approximation a CC ~ E: Standard term drops as 1/E 4, NSI-Term as 1/E 3  High energies important for NSI! a CC ~ E: Standard term drops as 1/E 4, NSI-Term as 1/E 3  High energies important for NSI!

Feb. 14, 2008Nu HoRIzons Walter Winter When does the silver channel help? Silver channel, in principle, very sensitive to  e ,   Silver channel, in principle, very sensitive to  e ,   Fix golden baselines: Where is the optimal silver baseline? (Use Silver* (5xSG,3xBG; all hadronic decay channels of the  observed) Fix golden baselines: Where is the optimal silver baseline? (Use Silver* (5xSG,3xBG; all hadronic decay channels of the  observed) IDS-NF MECC baseline = Golden 1 (Kopp, Ota, Winter, in prep.) (Kitazawa, Sugiyama, Yasuda, 2006)

Feb. 14, 2008Nu HoRIzons Walter Winter35 Minimum muon energy? Higher muon energy helps; low-E NF not an option Higher muon energy helps; low-E NF not an option Silver channel: Not relevant for IDS baseline; helps for E  ~ 50 GeV Silver channel: Not relevant for IDS baseline; helps for E  ~ 50 GeV IDS baselineHigh-E version (Kopp, Ota, Winter, in prep.) Low-E NuFact? IDS baseline High-E version Low-E NuFact? ~ Current bounds

Feb. 14, 2008Nu HoRIzons Walter Winter36 Two baseline optimization (no silver) Similar to matter effects (which increase with baseline!), NSI sensitivities want one very long baseline Similar to matter effects (which increase with baseline!), NSI sensitivities want one very long baseline Absolute sensitivity: Current limits improved by up to three orders of magnitude! Absolute sensitivity: Current limits improved by up to three orders of magnitude! (Kopp, Ota, Winter, in prep.)

37 New physics searches … and the physics case for  detection? Two approaches: Two approaches: 1)Have specific model, i.e., spectral dependence 2)Want to do general unitarity checks, i.e., no specific idea about spectral dependence Two solutions: Two solutions: 1)Use spectral dependence with model parameters But: much more statistics in P e , P  than P e  (cf., NSI example) 2)Use NC or CCs N e +N  +N  ; But for NC: Systematical uncertainties, CC contamination limit to percent level But for CC: Initial  : not possible because of MECC readout rate? Initial e : platinum CID (showers!), silver statistics again limited to few percent!? Is the conclusion that there is no physics case for the MECC at L 1 ? Is the conclusion that there is no physics case for the MECC at L 1 ? (Barger, Geer, Whisnant, 2004) NC: Systematic uncertainty in NC rate  NC and CC contaminations limit performance; limited to few percent?

Feb. 14, 2008Nu HoRIzons Walter Winter38 Summary and conclusions First generation superbeams (or reactor experiments) may find  13 ; however: no high- CL discovery of CPV, MH  Need upgrades! First generation superbeams (or reactor experiments) may find  13 ; however: no high- CL discovery of CPV, MH  Need upgrades! Current IDS-NF setup uses two baselines: Does INO match the detector requirements for the far detector? Current IDS-NF setup uses two baselines: Does INO match the detector requirements for the far detector? The physics case for the VL baseline is very robust (a number of applications) The physics case for the VL baseline is very robust (a number of applications) Open question: Do new physics searches require the silver channel? Open question: Do new physics searches require the silver channel?