beyond t2k and nova (… and reactor experiments) nufact 06 uc irvine, usa august 24, 2006 walter...

Beyond T2K and NOvABeyond T2K and NOvA(… and reactor experiments)(… and reactor experiments)

NuFact 06NuFact 06UC Irvine, USAUC Irvine, USAAugust 24, 2006August 24, 2006

Walter WinterWalter WinterUniversitUniversität Würzburg, Germanyät Würzburg, Germany

Aug. 24, 2006 NuFact 06 - Walter Winter 2

ContentsContents

IntroductionIntroduction Future experiment types:Future experiment types:

– Superbeam upgradesSuperbeam upgrades– Beta beamsBeta beams– Neutrino factoriesNeutrino factories

Decision making: Which experiment/type?Decision making: Which experiment/type? SummarySummary


Beyond T2K and NOvA: SettingBeyond T2K and NOvA: Setting Beyond T2K andBeyond T2K and

NOvA NOvA = beyond 2015?!= beyond 2015?!

Specific setups less Specific setups less certain than for the certain than for the coming ten yearscoming ten years

1313 discovered if discovered if

sinsin22221313 > 0.01 > 0.01

(from: FNAL Proton Driver Study)

GLoBES 2005


After T2K and NOvA: StatusAfter T2K and NOvA: Status 1313 discovered, some hint, or no signal at all discovered, some hint, or no signal at all

Even if Even if 1313 is very large and all data are combined: is very large and all data are combined:

– CP violation discovery unlikelyCP violation discovery unlikely– Mass hierarchy discovery 50:50 chance (in deltacp)Mass hierarchy discovery 50:50 chance (in deltacp)

(see, e.g., NOvA proposal, hep-ex/0503053)(see, e.g., NOvA proposal, hep-ex/0503053)

(90% CL solid, 3 dashed; from hep-ph/0403068)


What do we still want to know?What do we still want to know?

Discover Discover 1313 (if not yet done) (if not yet done)

Establish CP violation (at high CL)Establish CP violation (at high CL) Measure the mass hierarchy (at high CL)Measure the mass hierarchy (at high CL) Measure Measure 1313 precisely, say 5% in log precisely, say 5% in log1010(sin(sin22221313))

Measure Measure CPCP precisely, say 20 degrees precisely, say 20 degrees

Measure leading atm. parameters at per cent levelMeasure leading atm. parameters at per cent level Establish deviation from maximal mixingEstablish deviation from maximal mixing Verify MSW effect, Verify MSW effect,

constrain non-standard physics, etc.constrain non-standard physics, etc.

The only thing from this list which may happen early!


Options and representativesOptions and representatives

Major players:Major players: NOvA upgrades NOvA upgrades Wide band beamWide band beam

FNAL/BNL to FNAL/BNL to DUSELDUSEL

T2HK/T2KKT2HK/T2KK CERN SPLCERN SPL

Superbeamupgrade

Beta beamNeutrinofactory

Performance depends Performance depends on on ::

=100-150:=100-150:CERN-Frejus?CERN-Frejus?

~350:~350:Max. at CERN?Max. at CERN?

>> 350:>> 350:“Higher “Higher beam” beam”

Parameters:Parameters: Muon energyMuon energy BaselineBaseline Second baseline?Second baseline? Detector Detector

performanceperformance ChannelsChannels

Specific suggestions What to compare that to? Still green-field scenario

Superbeam upgradesSuperbeam upgrades


Upgrading NOvAUpgrading NOvA Simplest addition: Simplest addition:

A second detector, possibly liquid argonA second detector, possibly liquid argon Main purpose of NOvA: Main purpose of NOvA: 1313, , mass hierarchymass hierarchy In principle obtained by matter effects, i.e., long LIn principle obtained by matter effects, i.e., long L

Originally: Optimization of NOvA-T2K synergy byOriginally: Optimization of NOvA-T2K synergy by

(Barger, Marfatia, Whisnant, 2002; Huber, Lindner, Winter, 2003; Minakata, Nunokawa, (Barger, Marfatia, Whisnant, 2002; Huber, Lindner, Winter, 2003; Minakata, Nunokawa, Parke, 2003)Parke, 2003)

Two possibilities for upgrades: Two possibilities for upgrades: – Detector at same L/E but different L, i.e., matter effect (similar Detector at same L/E but different L, i.e., matter effect (similar

to above) to above) (Mena, Palomarez-Ruiz, Pascoli, 2005a/b)(Mena, Palomarez-Ruiz, Pascoli, 2005a/b)

– Detector at 2Detector at 2ndnd osc. Maximum (possibly at shorter L) osc. Maximum (possibly at shorter L)(NOvA proposal, hep-ex/0503053)(NOvA proposal, hep-ex/0503053)

See also WG 1:Howcroft


NOvA+2NOvA+2ndnd detector detector

Same L/E: Bi-probability ellipses shrink to linesSame L/E: Bi-probability ellipses shrink to lines MH discovery for all MH discovery for all CPCP for sin for sin22221313 > 0.04 > 0.04 More efficient than 2More efficient than 2ndnd osc. maximum for osc. maximum for running only running only

(Mena, Palomarez-Ruiz, Pascoli, 2005a/b)(Mena, Palomarez-Ruiz, Pascoli, 2005a/b)

Thin: 2nd osc. maxThick: Same L/E(2 x 50kt liquid argon, no PD)

5 yr

5 yr

5

yr

anti-

2.4o O

A


Broad band beam (1)Broad band beam (1) Idea: Use on-axis Idea: Use on-axis

beam for the simul-beam for the simul-taneous measurement taneous measurement of different oscillation of different oscillation maximamaxima

Probably FNAL or Probably FNAL or BNL to DUSELBNL to DUSEL(=Homestake/Henderson/…)(=Homestake/Henderson/…)

from FNAL: 1290/1487 km, from BNL: 2540/2770 kmfrom FNAL: 1290/1487 km, from BNL: 2540/2770 km Challenge: Backgrounds in a WC detectorChallenge: Backgrounds in a WC detector Compared to NOvA upgrades: New beamline required; Compared to NOvA upgrades: New beamline required;

therefore: Different timescale?therefore: Different timescale?

(Diwan et al, hep-ph/0303081; Diwan, hep-ex/0407047)(Diwan et al, hep-ph/0303081; Diwan, hep-ex/0407047)

See also WG 1:Bishai


Broad band beam (2)Broad band beam (2)

Baseline does not really matter so muchBaseline does not really matter so much Absolute performance very competitiveAbsolute performance very competitive

(New study using GLoBES: Barger et al, hep-ph/0607177)(New study using GLoBES: Barger et al, hep-ph/0607177)

1 MW, 5 yr ++ 2 MW 5yr anti-,300 kt WC detector;3

FNA

L

FNA

L

BN

L

BN

L

Worst case CP

Best case CP

“Typical” CP

“Typical” CP

Best case CP

CP frac. 0.75


T2K upgrades: T2HK, T2KKT2K upgrades: T2HK, T2KK

T2HK: Upgrade of T2K to megaton-size detector T2HK: Upgrade of T2K to megaton-size detector + 4 MW beam power+ 4 MW beam power

T2KK: Split detector mass into two identical T2KK: Split detector mass into two identical detectors in Japan+detectors in Japan+Korea (0.27+0.27 Korea (0.27+0.27 Mt) at same OA:Mt) at same OA:– Larger matter Larger matter

effects (L=1050 km) effects (L=1050 km)

– Reduce systematics Reduce systematics impactimpact

(T2HK: Itow et al, hep-ex/0106019; T2KK: Ishitsuka, Kajita, Minakata, Nunokawa, 2005)(T2HK: Itow et al, hep-ex/0106019; T2KK: Ishitsuka, Kajita, Minakata, Nunokawa, 2005)

See also WG 1:Okamura


What does the 1050 km baseline help?What does the 1050 km baseline help? What does it help that the detectors are identical?What does it help that the detectors are identical?

T2KK: Key questionsT2KK: Key questions

(Barger, Huber, Marfatia, Winter, in preparation)(Barger, Huber, Marfatia, Winter, in preparation)

“Cor

rela

ted

erro

rs”

betw

een

dete

ctor

s,bu

t unc

orre

late

d be

twee

n ne

utri

no-a

ntin

eutr

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chan

nels

!

(3m312=0.0025 eV2

PRELIMINARY


CERN-MemphysCERN-Memphys(a superbeam-beta beam hybrid)(a superbeam-beta beam hybrid)

Beta beam (Beta beam (=100) plus=100) plus4MW superbeam to 440 kt4MW superbeam to 440 ktWC detector at Frejus WC detector at Frejus site (L=130 km)site (L=130 km)

Effect of systematics smaller Effect of systematics smaller and absolute performance and absolute performance better than for T2HKbetter than for T2HK

Antineutrino running not Antineutrino running not necessary because necessary because ee to to (beta beam) and (beta beam) and to to ee (superbeam) channels (superbeam) channels presentpresent (Campagne, Maltoni, Mezzetto, Schwetz, 2006)(Campagne, Maltoni, Mezzetto, Schwetz, 2006)

10 years, 3Shading: systematics varied from 2% to 5%

Example: 13 discovery


Beta beamBeta beam

Key figure (any beta beam):Key figure (any beta beam):Useful ion decays/year?Useful ion decays/year?

““Standard values”:Standard values”:3 103 101818 66He decays/yearHe decays/year1 101 101818 1818Ne decays/yearNe decays/year

Can these be achieved?Can these be achieved? Typical gamma ~ 100 – 150 Typical gamma ~ 100 – 150

(for CERN SPS)(for CERN SPS)

eFeNe 189

1810

eLiHe 63

62

(CERN layout; Bouchez, Lindroos, Mezzetto, 2003; Lindroos, 2003; Mezzetto, 2003; Autin et al, 2003)

Compared to superbeam: no intrinsic beam BG limiting the sinCompared to superbeam: no intrinsic beam BG limiting the sin22221313 sensitivity to > 10 sensitivity to > 10-3-3

Compared to neutrino factory: no charge identification required,Compared to neutrino factory: no charge identification required,operation at the oscillation maximum possible/reasonableoperation at the oscillation maximum possible/reasonable

What is the physics case for a What is the physics case for a beta beam between SB and NF?beta beam between SB and NF?

(Zucchelli, 2002)

SEE ALSO NEXT TALK


From low to very high gamma From low to very high gamma ““Low” gamma (Low” gamma (<150?)<150?)

- Alternative to superbeam/synergy Alternative to superbeam/synergy with superbeam?with superbeam?

- Originally designed for CERN (SPS)Originally designed for CERN (SPS)- Water Cherenkov detectorWater Cherenkov detector(see before; also: Volpe, 2003; Campagne, Maltoni, (see before; also: Volpe, 2003; Campagne, Maltoni,

Mezzetto, Schwetz, 2006)Mezzetto, Schwetz, 2006)

““Medium” gamma (150<Medium” gamma (150<<350?)<350?)- Alternative to superbeam!Alternative to superbeam!- Possible at upgraded SPS?Possible at upgraded SPS?- Water Cherenkov detectorWater Cherenkov detector(Burguet-Castell et al, 2004+2005; Huber et al, 2005)(Burguet-Castell et al, 2004+2005; Huber et al, 2005)

““High” gamma (High” gamma (>> 350?)>> 350?)- Alternative to neutrino factory?Alternative to neutrino factory?- Requires large acceleratorRequires large accelerator- Detector technology other than water? Detector technology other than water? (Burguet-Castell et al, 2004; Huber et al, 2005; (Burguet-Castell et al, 2004; Huber et al, 2005;

Agarwalla et al, 2005)Agarwalla et al, 2005)

(Fig. from Huber, Lindner, (Fig. from Huber, Lindner, Rolinec, Winter, 2005)Rolinec, Winter, 2005)

(for NOvA-like detector!)

Gamma determines neutrino energyand therefore detector technology!

See also WG 1:Mezzetto, Fernandez-Martinez, Couce


Beta beam vs. Superbeam vs. NuFact?Beta beam vs. Superbeam vs. NuFact? Low/mediumLow/medium::

Can easily compete with Can easily compete with superbeam upgradessuperbeam upgrades

Higher Higher ::At least theoretically At least theoretically competitive to a neutrino competitive to a neutrino factoryfactory

Challenges:Challenges:- Can fluxes be reached?Can fluxes be reached?- Compare completely Compare completely

optimized accelerator optimized accelerator strategies?strategies?

- Mass hierarchy Mass hierarchy measurement for small measurement for small 1313

(Fig. from Huber, Lindner, Rolinec, Winter, 2005)(Fig. from Huber, Lindner, Rolinec, Winter, 2005)


Neutrino factoryNeutrino factory Ultimate “high precision” instrument!?Ultimate “high precision” instrument!? Muon decays in straight sections of storage Muon decays in straight sections of storage

ringring Technical challenges: Target power, muon Technical challenges: Target power, muon

cooling, charge identification, maybe steep cooling, charge identification, maybe steep decay tunnelsdecay tunnels

(from: CERN Yellow Report )

p

Target

, K

Decays

-Accelerator

Cooling

“Right sign”

“Wrong sign”

“Right sign”

“Wrong sign”

(Geer, 1997; de Rujula, Gavela, Hernandez, 1998; Cervera et al, 2000)

SEE ALSO ISS TALKS


Which baseline(s), which energy?Which baseline(s), which energy? 3000-5000 km good for3000-5000 km good for

CP violationCP violation 7500 km good for MH, as7500 km good for MH, as

degeneracy resolverdegeneracy resolver Use two baselines: Use two baselines:

4000 km+7500 km, E4000 km+7500 km, E > 40 GeV > 40 GeV

Mass hier.

CP violation13 sens.

Fig. from Huber, Lindner, Rolinec, Winter, hep-ph/0606119.

See also: Barger, Geer, Whisnant, 1999; Cervera et al, 2000; Burguet-Castell et al, 2001; Freund, Huber, Lindner, 2001


Why else want a very long baseline?Why else want a very long baseline?L ~ 6000-9000 kmL ~ 6000-9000 km

Example: Example: 1313 precision precision Depends on (true) Depends on (true) CPCP

(green band); thick (green band); thick curve: “typical” curve: “typical” CPCP (median)(median)

L ~ 7500 km as risk-L ~ 7500 km as risk-minimizer, and for minimizer, and for better absolute better absolute performanceperformance

In comb. with short In comb. with short baseline (L=4000 km) baseline (L=4000 km) less sensitive to Lless sensitive to L

(Gandhi, Winter, in preparation)(Gandhi, Winter, in preparation)


More R&D: Detector optimization?More R&D: Detector optimization?

Improved detector would Improved detector would increase sensitivity reach increase sensitivity reach significantlysignificantly

In addition: Lower EIn addition: Lower E = = 20 GeV possible (while 50 20 GeV possible (while 50 GeV do not harm)GeV do not harm)

Improve energy resolutionImprove energy resolution ? ?

Lower appearance Lower appearance threshold (CID!) to 1 GeV threshold (CID!) to 1 GeV + use more realistic BG + use more realistic BG modelmodel

Thick gray curve:Optimization

potential(Huber, Lindner, Rolinec, Winter, hep-ph/0606119)

See also WG 1:Cervera, Rubbia


Additional channels: Silver, PlatinumAdditional channels: Silver, Platinum Silver (Silver (ee to to ):):

– StandardStandard: 5kt ECC: 5kt ECC(Autiero et al, 2004)(Autiero et al, 2004)

– OptimisticOptimistic: 10kt ECC, 5xSIG, : 10kt ECC, 5xSIG, 3xBG3xBG

Platinum (Platinum ( to to ee):):– StandardStandard: 15 kt, 20% efficiency, : 15 kt, 20% efficiency,

~ 7.5 GeV upper threshold~ 7.5 GeV upper threshold(Rubbia, 2001)(Rubbia, 2001)

– OptimisticOptimistic: 50 kt, 40% : 50 kt, 40% efficiency, Eefficiency, E upper threshold upper threshold

Large Large 1313: Platinum useful?: Platinum useful? Medium Medium 1313: Both useful?: Both useful?

ButBut: Other choices in this : Other choices in this range!range!HoweverHowever: Unitarity tests? : Unitarity tests? (Antusch et al, 2006)(Antusch et al, 2006)

(Huber, Lindner, Rolinec, Winter, hep-ph/0606119)(Huber, Lindner, Rolinec, Winter, hep-ph/0606119)


NF optimization potentialNF optimization potential

Optimized NuFact: Excellent Optimized NuFact: Excellent 1313 reach for both MH and CPV reach for both MH and CPV But: For sinBut: For sin22221313 ~ 10 ~ 10-2-2, , =350 beta beam (L=730 km) better=350 beta beam (L=730 km) better

3

(Huber, Lindner, Rolinec, Winter, hep-ph/0606119; -beam: Burguet-Castell et al, hep-ph/0503021)


Decision making: SimplifiedDecision making: Simplified Do we have enough information to make a decision Do we have enough information to make a decision

after T2K and NOvA?after T2K and NOvA? Assumptions for this talk:Assumptions for this talk:

– We have to make a decision based on this informationWe have to make a decision based on this information– There will be no further incremental There will be no further incremental

approach to search for approach to search for (if not found) (if not found)= “One more experiment” hypothesis= “One more experiment” hypothesis

– We use the option with the lowest effort We use the option with the lowest effort if two physically similarif two physically similar

Key questions:Key questions:– Superbeam upgrade, beta beam, or neutrino factory?Superbeam upgrade, beta beam, or neutrino factory?– What setup within each class has the best physics What setup within each class has the best physics

performance?performance?

One

mor

e

expe

rimen

t?


Decision making: Physics casesDecision making: Physics cases Possible outcomes after T2K and NOvAPossible outcomes after T2K and NOvA

1.1. 1313 discovered discovered

2.2. Few Few hint for hint for 1313

3.3. 1313 not found not found A possible future strategy based on that (biased):A possible future strategy based on that (biased):

1.1. Best possible setup for large Best possible setup for large 1313 with reasonable effortwith reasonable effort = = Superbeam upgrade? But which?Superbeam upgrade? But which?Strategy: Max. CP fraction for discoveries for sinStrategy: Max. CP fraction for discoveries for sin22221313 > 0.04? > 0.04?

2.2. Best possible setup for intermediate Best possible setup for intermediate 1313 = =Beta beam with Beta beam with ~350? Other with better MH reach/longer L?~350? Other with better MH reach/longer L?Strategy: Max. CP fraction for discoveries for sinStrategy: Max. CP fraction for discoveries for sin22221313 ~ 0.01 ~ 0.01

3.3. Best possible reach in Best possible reach in 1313 for all performance indicators = for all performance indicators =Neutrino factoryNeutrino factoryStrategy: Disoveries for Strategy: Disoveries for 1313 as small as possible as small as possible


Decision making: ExampleDecision making: Example

Blue: Superbeam upgrade based upon: lower effortBlue: Superbeam upgrade based upon: lower effort Green: Beta beam based upon: Good CPV reach, MH in most casesGreen: Beta beam based upon: Good CPV reach, MH in most cases Red: Neutrino factory (optimized) based upon: Good Red: Neutrino factory (optimized) based upon: Good 1313 reach reach

(3m312=0.0022 eV2

Lon

ger

L


Which option for large Which option for large 1313??(from Huber et al, hep-ph/0601266) Based on assumptions Based on assumptions

before (lowest possible before (lowest possible effort): Superbeam?effort): Superbeam?

Depends on systematics:Depends on systematics:Requires more R&DRequires more R&D

Important selection Important selection criterion: Systematics criterion: Systematics robustness?robustness?

Depends on what Depends on what optimized for: MH or CPVoptimized for: MH or CPVTherefore: take two?Therefore: take two?


SummarySummary What is (more or less) known:What is (more or less) known:

– Neutrino factory best alternative for small Neutrino factory best alternative for small 1313 to measure to measure bothboth MH and CPV; MH and CPV;a very long baseline is an essential component of thata very long baseline is an essential component of that

– For large For large 1313, a different alternative may be better, a different alternative may be better– There may be a separate physics case for a beta beamThere may be a separate physics case for a beta beam

What is not known:What is not known:– Which setup for large Which setup for large 1313? ?

Possibly two, such as T2HK (for CPV) + WBB (MH)?Possibly two, such as T2HK (for CPV) + WBB (MH)?Which has the lowest systematics impact? T2KK?Which has the lowest systematics impact? T2KK?

– What is the precise physics case for a beta beam?What is the precise physics case for a beta beam?How does that affect the choice of How does that affect the choice of and L? and L?

– How far can a neutrino factory be optimized?How far can a neutrino factory be optimized?

beyond t2k and nova (… and reactor experiments) nufact 06 uc irvine, usa august 24, 2006 walter...

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