Neutrino factory physics reach Neutrino factory physics reach … and impact of detector performance… and impact of detector performance

22ndnd ISS Meeting ISS MeetingKEK, Tsukuba, JapanKEK, Tsukuba, Japan

January 24, 2006January 24, 2006

Walter WinterWalter WinterInstitute for Advanced Study, PrincetonInstitute for Advanced Study, Princeton

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 2

ContentsContents IntroductionIntroduction Optimization of a neutrino factory:Optimization of a neutrino factory:

– Muon energy and baselineMuon energy and baseline– Disappearance channel optimizationDisappearance channel optimization– Impact of detector performanceImpact of detector performance

Physics beyond the “big three” indicators:Physics beyond the “big three” indicators:((1313 discovery, CP violation, mass hierarchy) discovery, CP violation, mass hierarchy)

– 1313 and and CPCP precision measurements precision measurements– Physics case for Physics case for 1313=0?=0?– New physics testsNew physics tests– Geophysics with a neutrino factory?Geophysics with a neutrino factory?

SummarySummary

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 3

Appearance channels: Appearance channels: ee

Complicated, but all interesting information there: Complicated, but all interesting information there: 1313, , CPCP, mass hierarchy (via A), mass hierarchy (via A)

(Cervera et al. 2000; Freund, Huber, Lindner, 2000; Freund, 2001)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 4

Correlations and degeneraciesCorrelations and degeneracies Connected (green) or Connected (green) or

disconnected (yellow) disconnected (yellow) degenerate solutions (at a degenerate solutions (at a chosen CL) in parameter chosen CL) in parameter spacespace

Affect performance of Affect performance of appearance measurements. appearance measurements. For example, For example, 1313 sensitivity sensitivity

(Huber, Lindner, Winter, 2002)(Huber, Lindner, Winter, 2002) Discrete degeneracies: Discrete degeneracies: (also: Barger, Marfatia, Whisnant, 2001)(also: Barger, Marfatia, Whisnant, 2001)

Intrinsic (Intrinsic (,,1313)-degeneracy )-degeneracy (Burguet-Castell et al, 2001)(Burguet-Castell et al, 2001)

sgn-degeneracy sgn-degeneracy (Minakata, Nunokawa, 2001)(Minakata, Nunokawa, 2001)

((2323,,/2-/2-2323)-degeneracy )-degeneracy (Fogli, Lisi, 1996)(Fogli, Lisi, 1996)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 5

NF-Strategies to resolve degeneraciesNF-Strategies to resolve degeneracies… depend on sin… depend on sin22221313!!

Combine with superbeam upgradeCombine with superbeam upgrade((sinsin22221313 > 10 > 10-3-3) ) (Burguet-Castell et al, 2002)(Burguet-Castell et al, 2002)

Combine with “silver channels” Combine with “silver channels” ee -> -> ((sinsin22221313 > 10 > 10-3 -3 ?)?)(Donini, Meloni, Migliozzi, 2002; Autiero et al, 2004)(Donini, Meloni, Migliozzi, 2002; Autiero et al, 2004)

Better detectors: Higher energy Better detectors: Higher energy resolution, higher efficiencies atresolution, higher efficiencies atlow energies (CID!) low energies (CID!) ((sinsin22221313 > ?) > ?)(Later this talk)(Later this talk)

Second NF baseline: “Magic baseline” Second NF baseline: “Magic baseline” ((sinsin22221313 > 10 > 10-4-4))(Lipari, 2000; Burguet-Castell et al, 2001; Barger, Mafatia, Whisnant, 2002; Huber, Winter, 2003; others)(Lipari, 2000; Burguet-Castell et al, 2001; Barger, Mafatia, Whisnant, 2002; Huber, Winter, 2003; others)

Other possibilities?Other possibilities?

(Fig. from Huber, Lindner, Winter, 2002)

Intrinsic degeneracy disappears for better

energy threshold!sinsin22221313=0.001=0.001

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 6

Example: “Magic baseline”Example: “Magic baseline” Idea:Idea:

Yellow term = 0Yellow term = 0 independent independent of E, oscillation parametersof E, oscillation parameters(Huber, Winter, 2003)(Huber, Winter, 2003)

Purpose: Purpose: “Clean” measurement of “Clean” measurement of 1313 and mass hierarchy and mass hierarchy

Drawback: No Drawback: No CPCP measurement at magic baseline measurement at magic baseline combine with shorter baseline, such as L=3 000 kmcombine with shorter baseline, such as L=3 000 km

1313-range: 10-range: 10-4-4 < sin < sin22221313 < 10 < 10-2-2,,where most problems with degeneracies are presentwhere most problems with degeneracies are present

Optimization of a Optimization of a neutrino factoryneutrino factory

First time GLoBES is runon a parallel cluster!

4 yr x 1.06 104 yr x 1.06 102121 ++ decays + 4 yr 1.06 10 decays + 4 yr 1.06 102121 -- decays decaysDetector: 50 kt magnetized iron calorimeterDetector: 50 kt magnetized iron calorimeterISS-values? ISS-values?

100 kt, 5+5 years running time = factor 2.36 100 kt, 5+5 years running time = factor 2.36 luminosity increase for 10luminosity increase for 102121 useful decays/year useful decays/year

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 8

Muon energy and baseline: Muon energy and baseline: 1313

Example: Example: 1313 sensitivity sensitivity

relativerelative to minimum to minimum in in each plot (3each plot (3))

Important result:Important result:Since muon energy ~ $Since muon energy ~ $40 GeV enough?!40 GeV enough?!

Threshold effects:Threshold effects:

(Huber, Lindner, Rolinec, Winter, to appear; also: Freund, Huber, Lindner, 2001)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 9

Muon energy and baseline: CP violationMuon energy and baseline: CP violation

Degeneracy problem for Degeneracy problem for CPCP=3=3/2 not solvable without /2 not solvable without additional information or improvementsadditional information or improvements

Example: Sensitivity to max. CP violation Example: Sensitivity to max. CP violation (absolute “conservative” reach, 3(absolute “conservative” reach, 3))

(Huber, Lindner, Rolinec, Winter, to appear)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 10

Muon energy and baseline: Mass hierarchyMuon energy and baseline: Mass hierarchy Example: Sensitivity to normal hierarchy (absolute reach, 3Example: Sensitivity to normal hierarchy (absolute reach, 3))

(Huber, Lindner, Rolinec, Winter, to appear)

If sinIf sin22221313 small: Very long baseline necessary! small: Very long baseline necessary!

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 11

Disappearance channelDisappearance channel Disappearance information Disappearance information

important to reduce errors on important to reduce errors on leading parametersleading parameters(see e.g. Donini, Fernandez-Martinez, Rigolin, 2005; Donini, Fernandez-Martinez, Meloni, Rigolin, 2005)

IdeaIdea: Use data sample : Use data sample without charge without charge identification for identification for disappearance, i.e., disappearance, i.e., add right and wrong add right and wrong sign muon eventssign muon events

Better eff. at low E!Better eff. at low E!

(de Gouvea, Winter, 2005; Fig. from Huber, Lindner, Rolinec, Winter, to appear)

sinsin

2222 1313 =

0 =

0

(Fig. from Huber, Lindner, Winter, 2002)

sinsin22221313 precision precision

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 12

Better detector? Hybrid detector?Better detector? Hybrid detector? Better energy resolution?Better energy resolution?

Was: 0.15 x E (approximation) Was: 0.15 x E (approximation) Optimistic: ? Optimistic: ?

Lower appearance threshold?Lower appearance threshold?Was: 4 GeV, linearly Was: 4 GeV, linearly climbing to maximum at 20 GeVclimbing to maximum at 20 GeVOptimistic: Max. already at 1 GeVOptimistic: Max. already at 1 GeV

CC/NC Backgrounds: Assume CC/NC Backgrounds: Assume power low such that power low such that ~ 5 x 10~ 5 x 10-6-6 each at mean energies each at mean energies Background increases at low energiesBackground increases at low energies Even if CID improved, NC background limits performance!Even if CID improved, NC background limits performance!

(Fig. from Huber, Lindner, Winter, 2002;

Gray curve from Cervera et al, 2000)

(Cervera et al, 2000)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 13

Better detector: 4 toy scenariosBetter detector: 4 toy scenarios1.1. ““Standard”Standard”

Appearance with “standard” threshold climbing from 4 to 20 GeVAppearance with “standard” threshold climbing from 4 to 20 GeV 15% E energy resolution15% E energy resolution Disappearance without CIDDisappearance without CID Background constant in EBackground constant in E

2.2. ““Optimal appearance”Optimal appearance” Appearance with better threshold + better EresAppearance with better threshold + better Eres Disappearance with CID !!! (old)Disappearance with CID !!! (old) Better background modelingBetter background modeling

3.3. ““Better Eres”Better Eres” Like 2, but “old” thresholdLike 2, but “old” threshold

4.4. ““Better threshold”Better threshold” Like 2, but “old” Eres modeled as 0.5 Sqrt(E)Like 2, but “old” Eres modeled as 0.5 Sqrt(E)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 14

Better detector: Better detector: 1313 sensitivity sensitivity

High CL chosen (4High CL chosen (4):):avoid threshold effectsavoid threshold effects

((1313,,CPCP)-degeneracy )-degeneracy

affects sensitivity limitaffects sensitivity limitat L ~ 1500-5000 kmat L ~ 1500-5000 km

Better detector threshold:Better detector threshold:L=2000-3000 km most L=2000-3000 km most attractive attractive 1313-baseline-baseline

“Magicbaseline”

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 15

Better detector: MH, Better detector: MH, CPCP

Choose Choose CPCP=3=3/2 because most problems with degeneracies around there: /2 because most problems with degeneracies around there: Cannot be completely resolved!Cannot be completely resolved!

Both Eres and threshold increase sensitive region; Especially: better thresholdBoth Eres and threshold increase sensitive region; Especially: better threshold

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 16

Better detector: Large Better detector: Large 1313

Both better Eres and threshold usefulBoth better Eres and threshold useful Both better detector and smaller matter density uncertainty usefulBoth better detector and smaller matter density uncertainty useful Either or combination sufficient to compete with the superbeam upgrades (prel.)Either or combination sufficient to compete with the superbeam upgrades (prel.) Large Large +better detector prefers shorter baselines (1000-2000km); E+better detector prefers shorter baselines (1000-2000km); E small OK small OK

No

CP a

t Lm

agic!

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 17

Better detector: SummaryBetter detector: Summary Better threshold helps forBetter threshold helps for

– Optimization: Optimization: » 3000 km competitive for 3000 km competitive for 13 13 (compared to 7500 km)(compared to 7500 km)

But:But: depends on chosen CL and finally achieved luminosity depends on chosen CL and finally achieved luminosity» Lower ELower E possible (not shown); 30 GeV muons? possible (not shown); 30 GeV muons?

– Better absolute reaches (MH, Better absolute reaches (MH, CPCP)) Better energy resolution helps for Better energy resolution helps for

– Leading parameter measurements (very preliminary)Leading parameter measurements (very preliminary)– Indirectly for sub-leading parametersIndirectly for sub-leading parameters– Somewhat better absolute reaches (MH, Somewhat better absolute reaches (MH, CPCP))

However: Even optimal detector cannot resolve However: Even optimal detector cannot resolve degeneracies completely!degeneracies completely!

Physics beyond the “big three” Physics beyond the “big three” indicatorsindicators

((1313 discovery, CP violation, mass hierarchy) discovery, CP violation, mass hierarchy)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 19

Precision of Precision of 1313 How precisely can one measure How precisely can one measure 1313 if found? if found?

Dependence on Dependence on CPCP characterized by bands: characterized by bands:

Qualitatively similar behavior to Qualitatively similar behavior to CPCP precision precision

(Fig. from Huber, Lindner, Winter, 2002)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 20

Precision of Precision of CPCP / CP coverage / CP coverage Define: CP coverage = Fraction of all fit values of Define: CP coverage = Fraction of all fit values of

which fit a chosen true which fit a chosen true CP coverage <= 360 CP coverage <= 360oo

CP scaling CP pattern

2 =

9, 4, 1; dashed: no degs)(F

ig. f

rom

Hub

er, L

indn

er, W

inte

r, h

ep-p

h/04

1219

9)

True values of True values of and and 1313 affect topology! Degeneracies! affect topology! Degeneracies!

But: Degeneracies not everywhere in param. space importantBut: Degeneracies not everywhere in param. space important

Degeneracy problemeven bigger than

for max. CP violation!

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 21

CP coverage and “real synergies”CP coverage and “real synergies”

3 000 km + 7 500 km3 000 km + 7 500 kmversus all detector mass at versus all detector mass at 3 000 km (2L)3 000 km (2L)

Magic baseline allows a Magic baseline allows a risk-minimized risk-minimized measurement (unknown measurement (unknown ))

““Staged neutrino factory”: Staged neutrino factory”: Option to add magic Option to add magic baseline later if in “bad” baseline later if in “bad” quadrants?quadrants?

Any “extra” gain beyond a simple addition of statistics

One baseline enoughOne baseline enough Two baselines necessaryTwo baselines necessary(Huber, Lindner, Winter, 2004)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 22

Physics case for Physics case for 1313=0?=0?Establish MSW effect for 13=0by solar oscillation (appearance prob.)

L > 5,500 km

(Winter, 2004)

Determine mass hierarchy for 13=0(disappearance probability)

L ~ 6,000 km

(de Gouvea, Jenkins, Kayser, 2005; de Gouvea, Winter,2005)

Very long (>> 3,000 km) baseline important component of any such program!In addition: 13=0 would be an important indicator for some symmetry!

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 23

New physics testsNew physics testsTest unitarity and small ad-mixtures of “new physics” by:Test unitarity and small ad-mixtures of “new physics” by: detection Pdetection Peeee+P+Pee++PPee = 1? = 1? (Donini, Meloni, Migliozzi, 2002; Autiero et al, 2004)(Donini, Meloni, Migliozzi, 2002; Autiero et al, 2004) Neutral currents (hard)Neutral currents (hard) (Barger, Geer, Whisnant, 2004) (Barger, Geer, Whisnant, 2004) Spectral signature on probability levelSpectral signature on probability level

Example: Example: Damping Damping effectseffects(Blennow, (Blennow, Ohlsson, Ohlsson, Winter, Winter, hep-ph/0502147)hep-ph/0502147)

More complicated: Hamiltonian-level effectsMore complicated: Hamiltonian-level effects(e.g., Blennow, Ohlsson, Winter, hep-ph/0508175)(e.g., Blennow, Ohlsson, Winter, hep-ph/0508175)

Example: Oscillation-NSI confusion theoremExample: Oscillation-NSI confusion theorem(Huber, Schwetz, Valle, 2002)(Huber, Schwetz, Valle, 2002)

See other talks inthis workshop for

specific possible effects!E.g. Hisano, Kanemura,

Sato, Sorel, Xing

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 24

Other physics: Geophysics?Other physics: Geophysics?Example: Measure inner core density Example: Measure inner core density ICIC

Per cent level precision not unrealisticPer cent level precision not unrealistic Survives unknown oscillation parametersSurvives unknown oscillation parameters More recent discussions: Discriminate seismically degenerate More recent discussions: Discriminate seismically degenerate

geophysics models in mantle, test plum hypothesis etc.?geophysics models in mantle, test plum hypothesis etc.?

(Winter, 2005)(Winter, 2005)

BNLCERN

JHF

Inner core

shadow

sin2213=0.01

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 25

Summary and conclusionsSummary and conclusions Energy and baseline optimization:Energy and baseline optimization:

Muon energy of 40 GeV enough!?Muon energy of 40 GeV enough!?L=1000 km, EL=1000 km, E=20 GeV not an option!?=20 GeV not an option!?

Better detector will definitively helpBetter detector will definitively helpEspecially: Better threshold (app. low energy efficiency)Especially: Better threshold (app. low energy efficiency)

There is plenty of “beautiful” neutrino oscillationThere is plenty of “beautiful” neutrino oscillationphysics beyond “standard” physics beyond “standard” 1313, mass hierarchy, CP , mass hierarchy, CP violation. Example: Physics case violation. Example: Physics case 1313=0=0

Problem for any “serious” calculation: calculation time! Problem for any “serious” calculation: calculation time! So far calculated on opportunistic systems with greatly So far calculated on opportunistic systems with greatly variable calculation time! Parallel cluster time needed!variable calculation time! Parallel cluster time needed!Example: One L-E-Plot takes ~ 300-500 CPU hoursExample: One L-E-Plot takes ~ 300-500 CPU hours

Next steps: Channel requirements, …Next steps: Channel requirements, …

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 26

Better detector in L-E-space: Better detector in L-E-space: 13 13 sens.sens. 33 sensitivity to sin sensitivity to sin22221313

Better Eres Better threshold Better Eres+thresh.

(Huber, Lindner, Rolinec, Winter, to appear)

Jan. 24, 2006 ISS KEK NuFact - Walter Winter 27

Better detector in L-E-space: Large Better detector in L-E-space: Large 1313

CP fraction for CP CP fraction for CP violation (3violation (3

“Standard”“Standard”

“Optimal “Optimal appearance”appearance”L=1000 km/EL=1000 km/E=20 GeV=20 GeV

possible alternative?possible alternative?(Huber, Lindner, Rolinec, Winter, to appear)