Alternating ions in a Beam to solve degeneracies

E. Fernández-Martínez, IFT-U.A.M. Madrid

Based on A. Donini, E.F.M. hep-ph/0603261

Motivations Evidence of physics beyond the SM Many open questions:

Masses? Absolute mass scale? Normal or inverted hierarchy?

Mixing? Large compared with CKM 23 = 45º? 13 = 0º? CP violation?

Dirac or Majorana particles?

Origin of masses

Leptogenesis

A new generation of neutrino experiments is needed to answer these questions

The oscillation parameters

What we already know

Solar sector

Atm sector

What we still don’t know sin2(213) < 0.12

cp

Mass hierarchy

Octant of 23

223msignsatm

232tan signsoct

06.005.012

2

257.07.0

212

314.0sin

eV109.7

m

18.010.023

2

235.06.0

223

44.0sin

eV104.2

m

23 = 36º–52º

12 = 31º–38º

13 < 10º

G.L. Fogli et al. hep-ph/0506083

Waiting for a global fit including MINOS!

The degeneracy problem

There is a curve of solutions

J. Burguet-Castell et al. hep-ph/0103258

Black square = input “true” value

If we add antineutrinos the two curves intersect in 2 regions: The true solution and an intrinsic degeneracy

The degeneracy problem

Two other unknown parameters:

Eightfold degeneracy:Intrinsic sign octant mixed

octatmss ,

There are 4 different sets of curves for different choices of

2 Intersections each

H. Minakata et al. hep-ph/0108085G.L.Fogli et al. hep-ph/9604415 V. Barger et al. hep-ph/0112119

octatmss ,

Beam

Maximum limited to 250/150 for 18Ne/6He with the SPS

Beam fluxes

6LiE=3.5MeV

18Ne

6He

500kt fiducial mass water Cerenkov detector at L=130km

18FE=1.7MeVE=2.4MeVE=3.4MeV

e GeVE 44.0=1.7s

GeVE 46.0e=0.8s

1180 109.2 yrdecays

1180 101.1 yrdecays

Beam fluxes

6LiE=3.5MeV

19Ne

6He

500kt fiducial mass water Cerenkov detector at L=130km

19FE=2.2MeV

e GeVE 47.0=17.2s

GeVE 46.0e=0.8s

1180 109.2 yrdecays

1180 101.1 yrdecays

Event Rates

E (GeV) 0-0.5 0.5-0.75

0.75-0.9

18Ne 710 403 40

Background 476 138 20

6He 852 595 50

Background 585 32 3

Migration and Background matrices from J. Burguet-Castell et al. hep-ph/0503021

For 10yr exposure of each beam to a 500kt water Cerenkov detector

= 5º= 0ºL = 130km

Beam degeneracies

Intrinsic sign octant mixed90% cl contours

Ne/He at L=130Km

Inputs 13 = 5º, 8º= 0º, -90º, 45º

B And LiBeam fluxes

8BeE=13.0MeV

8B

8Li

8BeE=13.9MeV

e GeVE 44.1=0.77s

GeVE 34.1e=0.8s

1180 109.2 yrdecays

1180 101.1 yrdecays

A new way to produce 8B and 8Li can be found in C.Rubbia et al. hep-ph/0602032

Event Rates

E (GeV) 0-0.5 0.5-0.75

0.75-0.9

18Ne 23 9 1

Background 10 3 0

6He 36 19 1

Background 12 0 0

E (GeV) 0.5-0.75

0.75-1

1-1.25

1.25-1.5

1.5-1.75

1.75-2

2-2.45

8B 4 7 10 11 8 5 3

Background 18 8 4 2 0 1 08Li 6 7 13 16 12 9 5

Background 23 4 1 1 0 0 0Migration and Background matrices from J. Burguet-Castell et al. hep-ph/0503021

For 5yr exposure of each beam to a 500kt water Cerenkov detector

= 5º= 0º

L = 650km

Solving degeneracies

Intrinsic sign octant mixed90% cl contours

Ne/He at L=130Km Ne/He/B/Li at L=650Km

Inputs 13 = 5º, 8º= -90º, 45º

Sensitivities

3 contours

Sensitivity to sin2(213)

Ne/He at L=130Km

Ne/He/B/Li at L=650Km

Sensitivities

3 contours

Sensitivity to sin2(213)

Ne/He at L=130Km

Ne/He/B/Li at L=650Km

Ne/He at L=650Km

Sensitivities

3 contours

Sensitivity to sin2(213) Sensitivity to the hierarchy

Ne/He at L=130Km

Ne/He/B/Li at L=650Km

Ne/He at L=650Km

Conclusions

If 13 is large, i.e. it is measured at T2K-I, alternating B and Li at the first peak with Ne and He at the second at L=650km reduces the eightfold degeneracy to a twofold one

The remaining octant degeneracy could be solved by combining with reactor, see K. Hiraide et al. hep-ph/0601258, or atmospheric data, see P. Huber et al. hep-ph/0501037 and J. E. Campagne et al. hep-ph/0603172

Sensitivity to the hierarchy is achieved for low and even if higher are accessible, the ion mix with lower outperforms it for some values of

B and Li accelerated to higher give very energetic neutrino fluxes that could exploit denser detectors like iron calorimeters or ECC

Beam degeneracies

Intrinsic sign octant mixed90% cl contours

Ne/He at L=650Km B/Li at L=650Km

Inputs 13 = 5º,8º= -90º,45º

The ionization cooling procedure

Li + D →Li + p

Li + He →B + n

C.Rubbia et al. hep-ph/0602032

An excess of 1014 ions/scould be accumulated

Cross sections

Different cross-sections can differ up to a factor of 2 below 0.5GeV (at 0.2GeV)

Comparison of LIPARI (black) and NUANCE (red) cross-section

We used the LIPARI cross-section that takes into account nuclear effects important below 0.2GeV

The cross-sections will be measured by the experiments