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Andrea Donini I.F.T.-U.A.M. Madrid with thanks to Enrique - - PowerPoint PPT Presentation

Jan 24, 2023 195 likes •417 views

The merits (and de-merits) of the Silver Channel at the Neutrino Factory Andrea Donini I.F.T.-U.A.M. Madrid with thanks to Enrique Fernndez-Martnez, Patrick Huber, Jacobo Lpez-Pavn, Davide Meloni, Pasquale Migliozzi, Stefano Riglin

slide-1
SLIDE 1

The merits (and de-merits)

  • f the Silver Channel at the Neutrino Factory

Andrea Donini I.F.T.-U.A.M. Madrid with thanks to Enrique Fernández-Martínez, Patrick Huber, Jacobo López-Pavón, Davide Meloni, Pasquale Migliozzi, Stefano Rigólin

slide-2
SLIDE 2

Outline

 The Golden Channel: νe→νμ  The degeneracy problem  The Silver Channel: νe→ντ  Limitations of the Silver Channel  How to improve the Silver Channel  The νμ→ντ Channel  νe→ντ and νμ→ντ for other means:

 unitarity of the PMNS matrix  sterile neutrinos  ...

2

slide-3
SLIDE 3

Oscillation Parameters

 What we already know (at 2σ)

 Solar sector  Atm. sector

 What we still don’t know

 sin2θ13 < 0.031  δ  Mass hierarchy  θ23 octant

G.L. Fogli hep-ph/0608060

θ23 = 36º–52º θ12 = 33º–35º θ13 < 10º

   ∆m2

12

= 7.9+0.7

−0.7 × 10−5eV2

sin2 θ12 = 0.314+0.06

−0.05

   |∆m2

23|

= 2.6+0.4

−0.4 × 10−3eV2

sin2 θ23 = 0.45+0.16

−0.09

satm = sign(∆m2

23)

soct = sign(tan 2θ23)

slide-4
SLIDE 4

Need for a magnetized detector

The Golden Channel

 The νe →νμ oscillation probability in matter 4

P ±

eµ = X± µ sin2 2θ13+Y ± µ sin 2θ13 cos

  • δ ∓ ∆atmL

2

  • + Zµ

At the Neutrino Factory:

µ+ →    e+ ¯ νµ → ¯ νµ → µ+ νe → νµ → µ−

slide-5
SLIDE 5

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

slide-6
SLIDE 6

The degeneracy problem

 Two other unknown

parameters:

Eightfold degeneracy: Intrinsic sign octant mixed

2 Intersections each

  • H. Minakata et al. hep-ph/0108085

G.L.Fogli et al. hep-ph/9604415

  • V. Barger et al. hep-ph/0112119

satm, soct

There are 4 different sets

  • f curves for different

choices of

satm, soct

slide-7
SLIDE 7

Need to identify the decay vertex and the muon charge

 The νe →ντ oscillation probability in matter

The Silver Channel

7

P ±

eτ = X± τ sin2 2θ13−Y ± τ sin 2θ13 cos

  • δ ∓ ∆atmL

2

  • + Zτ

µ+ →    e+ ¯ νµ → ¯ νµ → µ+ νe → ντ → τ − → µ−

At the Neutrino Factory:

slide-8
SLIDE 8

Event curves for golden and silver muons

8

!! !" # " !

!!"

!!## !"## # "## !##

#

$!"!#"$% $!"!#"$"

  • A. Donini, D. Meloni and P. Migliozzi, hep-ph/0206034
slide-9
SLIDE 9

The Detector: an OPERA-like 5 Kton ECC

9

slide-10
SLIDE 10

The Detector: an OPERA-like 5 Kton ECC

10 8

slide-11
SLIDE 11

The Golden channel at the NuFact

11

Golden channel at 3000km Input values θ13 = 2º, 5º and 8º δ = 45º, -90º 90% CL contours with 2% systematic error True sign octant mixed

slide-12
SLIDE 12

The Golden and Silver channels at the NF

12

Golden and Silver channel at 3000km Input values θ13 = 2º, 5º and 8º δ = 45º, -90º 90% CL contours with 2% systematic error True sign octant mixed

slide-13
SLIDE 13

Limitations of the Silver Channel

 The main limitation is STATISTICS. 13

2000 4000 6000 8000 LMID km 101 102 103 104 sin22Θ13 sensitivity limit Golden only Golden Silver Golden Platinum All three channels

3Σ

GLoBES 2006

LECC LMID 2000 4000 6000 8000 LMID km 101 102 103 104 sin22Θ13 sensitivity limit 2000 4000 6000 8000 LMID km 101 102 103 104 True value of sin22Θ13 Mass hierarchy for ∆CP3Π2 3Σ

Golden only GoldenSilver GoldenPlatinum All three channels GLoBES 2006

LECC LMID 2000 4000 6000 8000 LMID km 101 102 103 104 True value of sin22Θ13 Mass hierarchy for ∆CP3Π2 3Σ

  • P. Huber, M. Lindner, M. Rolinec and W. Winter, hep-ph/0606019
slide-14
SLIDE 14

How to improve the Silver Channel?

 Difficult:

 increase the mass?

14

Not realistic: e.g., not enough emulsions....

slide-15
SLIDE 15

 Difficult:

 Increase the mass?  Magnetize the detector to use more τ decay channels?

How to improve the Silver Channel?

15

slide-16
SLIDE 16

How to improve the Silver Channel?

 Difficult:

 Increase the mass?  Magnetize the detector to use more τ decay channels?

16 15

See the ISS Detector Working Group Report

B

→

slide-17
SLIDE 17

The νμ→ντ channel

 Limited impact at the Neutrino Factory for the

standard scenario

17

1 2 3 4 5 6 7 8 9 10 Θ13 0.0021 0.0023 0.0025 0.0027 0.0029 m223 36 38 40 42 44 46 48 50 52 54 Θ23 0.0021 0.0023 0.0025 0.0027 0.0029 m223

νµ→ντ νµ→νµ νµ→ντ + νµ→νµ

slide-18
SLIDE 18

Atmospheric term CP-interference Zero distance effect

 Crucial beyond the three-family oscillation scenario

 to test unitarity of the PMNS matrix

18

The νμ→ντ channel

Pµτ = sin2 2θµτ sin2 ∆atmL 2 + 2Im(µτ) sin 2θµτ sin ∆atmL 2 + 4|µτ|2

At a 50 GeV Neutrino Factory with L = 130 Km the atmospheric term is suppressed

slide-19
SLIDE 19

The νμ→ντ channel

19  Crucial beyond the three-family oscillation scenario

 to test unitarity of the PMNS matrix

104 103 102 101 ΗeΤ 180 90 90 180 ∆eΤ 104 103 102 101 ΗΜΤ 180 90 90 180 ∆ΜΤ

  • E. Fernández-Martínez, M.B. Gavela, J. López-Pavón and O. Yasuda, hep-ph/0703098
slide-20
SLIDE 20

The νμ→ντ channel

 Crucial beyond the three-family oscillation scenario

 to test unitarity of the PMNS matrix  to look for sterile neutrinos

20 17

20 40 60 80

!!"

0.004 0.008 0.012

P#" P#e

solid lines = including matter effects dashed lines = no matter effects 20 40 60 80

!!"

20 40 60 80

!#"

!$"%&

"

!$"%!&

"

!$"%"&

"

!$"%'(

"

  • A. Donini et al., in preparation
slide-21
SLIDE 21

Conclusions

The Golden Channel at the Neutrino Factory is extremely powerful to measure θ13 and δ. However, it is strongly affected by degeneracies

The Silver Channel can be used to solve part of the degeneracies for θ13 not too small: θ13 ≥ 1°-2°

The Silver Channel and the Platinum Channel gave similar results in degeneracy-solving in this region of θ13. They are both statistically limited: is it possible to increase the signal?

An ECC can be used also to look for νμ→ντ oscillation:

this channel is of limited interest for standard three-family

  • scillation, since νμ→νμ disappearance at the MIND

detector gives same results in any case

however, it is extremely interesting to look for new physics beyond three-family oscillation

slide-22
SLIDE 22

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