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- Neutrino physics using quantum coherence - M. Yoshimura Okayama University, Japan Outline of this talk Introduction: remaining important questions in neutrino

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量子重イオンビームを利用した、新たなニュートリノ物理

  • Neutrino physics using quantum coherence -
  • M. Yoshimura

Okayama University, Japan

Outline of this talk

m.yoshimura 09/16/2015 @基研 1

Introduction: remaining important questions in neutrino physics quantum coherence: an example of adiabatic Raman excitation De-excitation from quantum ion beam in circular motion Expected physics outputs in neutrino physics

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Present status of neutrino physics

  • Oscillation experiments

– Finite mass – Flavor mixing – Only mass-squared difference can be measured.

νe|Uei|2] νµ[|Uµi|2] ντ |Uτi|2]

Normal (NH) Inverted (IH) ∆m2

atm= (50meV)2

sin2θ13 sin2θ13

∆m2

sol

ν1 ν2 ν3

(Mass)

}

ν3 ν1 ν2

}

  • r

∆m2

sol= (10 meV)2

∆m2

atm

2

m.yoshimura 09/16/2015 @基研

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Important questions left in neutrino physics

  • Absolute mass scale and the smallest mass (oscillation experiments

are sensitive to mass squared differences alone)

  • Majorana vs Dirac distinction
  • CPV phase （Majorana case has 2 extra phases）
  • Detection of relic 1.9K neutrino

These are relevant to explanation of matter-antimatter imbalance of universe and physics beyond the standard theory.

3 m.yoshimura 09/16/2015 @基研

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4

Significance of Majorana neutrinos

  • Theoretical prejudice: Neutral leptons consist of 4 components like

all other quarks and leptons, the ordinary massless neutrino and the

  • ther 2-component partner having a much larger mass of Majorana-

type than the Fermi scale

  • -> Seesaw mechanism with a Dirac-type coupling via Higges
  • Plausible scenario of lepto-genesis

Heavy Majorana decay responsible for generation of lepton asymmetry, being

converted to baryon asymmetry via strong electroweak B, L violation keeping B-L conserved.

Prerequisite: ordinary neutrinos are massive、but very light Majorana.

New CPV sources related to heavy partners of mass >> Fermi scale

m.yoshimura 09/16/2015 @基研

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m.yoshimura 09/16/2015 @基研 5

Dirac eq.： degenerate 2 Majorana

2-component in weak process involved

Anti-particle creation Particle annihilation

Majorana eq. : particle=antiparticle

2 neutrino wave functions are anti-symmetrized Majorana ｖｓ Dirac equations chirally projected solutions

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Detection principles

１．Majorana/Dirac distinction: identical fermion effects, different effects from SPAN because energy-momentum conservation do not hold and mass threshold regions exist in all photon energy regions

m.yoshimura 09/16/2015 @基研 6

SPAN case

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Pair emission probability after helicities summation: MD cases

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Majorana term Common terms

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,

２．Lepton number violation can occur either in propagator or as a vertex

m.yoshimura 09/16/2015 @基研 8

Responsible in neutrino-less double beta decay, but see our examples below

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References

m.yoshimura 09/16/2015 @基研 9

Conventional neutrino sources: pi-, mu-, beta-decay We shall use de-excitation of circulating excited heavy ions, producing pairs of neutrino and anti-neutrino.

arXiv: 1505.07572v2 [hep-ph] arXiv：1506.08003v1 [hep-ph] arXiv: 1508.02795v2 [hep-ph] バグあり。以下で修正。

Paper in preparation

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Quantum heavy ion beam

m.yoshimura 09/16/2015 @基研 10

直線部分でレーザーを対向照射して励起

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Schwinger’s formula for synchrotron radiation

  • Main results

Exponential cutoff, both in energy and angular directions, only to keV region available. But flux is much, much larger than decay product.

  • Phase integral: same sign phase adds up

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光子数、光子エネルギー ともに指数関数減衰 neV x ¥gamma^3

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Neutrino pair emission occurs similarly to synchrotron radiation, But, producing neutrino pairs in the keV energy region with extremely small rates, hence completely negligible for both electron synchrotron and heavy ion in the ground state circulating

m.yoshimura 09/16/2015 @基研 12

Input of excitation energy, leading to a kind of non-linear resonance given by stationary points （positive and negative phases cancellation) in a phase integral over times

New feature for excited ions

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Prepa eparation

  • n of
  • f i

ini nitial coher

  • heren

ence – Adi diaba abatic R Ram aman an -

= v 1 = v

532nm 683nm

δ

e 2 sin g 2 cos e 2 sin g 2 cos θ θ θ θ

ϕ ϕ i i

e e

− −

− = − + = +

g

Ω

e

Ω

Two laser fields irradiates p-H2 Non-degenerate Superposition States: Two photon Rabi frequency

∆ ≅

e g ge

Ω Ω Ω

|g> and |e> are mixed with an angle

δ θ

ge

tan Ω ≅ θ ρ sin 2 1 =

eg

0eV 0.5 eV

2.3 eV

11 eV Coherence between |e> and |g>

∆

+

Σu

1

B

“coherence”

m.yoshimura 09/16/2015 @基研 13

２つのレーザー照射

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e 2 1 g 2 1

ϕ i

e− ± = ±

2 π θ =

g = ± = θ g = ± = θ

532nm 683nm

p-H2 gas

e 2 sin g 2 cos θ θ

ϕ i

e− ± = ±

≠ θ

e 2 sin g 2 cos θ θ

ϕ i

e− ± = ±

≠ θ

m.yoshimura 09/16/2015 @基研 14

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Two useful processes: pair emission and RENP (radiative neutrino pair emission) from circulating excited ions

m.yoshimura 09/16/2015 @基研 15

Beam RENP Neutrino-pair beam

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How to calculate RENP emission rate

  • Semi-classical approximation: classical ion CM motion and quantum

internal state

  • Spin current dominance from valence electron transition

m.yoshimura 09/16/2015 @基研 16

hamiltonian coherence Ion trajectory Spin factor

CP-even

Mixture of well-defined phase

－＞

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Some details of calculation

m.yoshimura 09/16/2015 @基研 17

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m.yoshimura 09/16/2015 @基研 18

In the large radius (¥rho) limit 位相因子の積分で停留点近似を行う

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Difference from usual synchrotron radiation

m.yoshimura 09/16/2015 @基研 19

  • Always the same sign phase added, leading to exponential dampling

Ground state ion

X = rescaled time

Excited ion with coherence

Cancellation of positive and negative phases Energy input leads to resonance-like behavior

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Intuitive understanding

  • A kind of non-linear resonance: orbital energy

balanced against internal ion energy, giving non-linear resonance oscillation. Its width around the stationary point gives a sharp resonance-like behavior in time domain.

  • Key concept for its success: quantum coherence

typically realized by ionic system under laser irradiation, but may persist without phase relaxation.

m.yoshimura 09/16/2015 @基研 20

Simple example of quantum coherence: adiabatic Raman process

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m.yoshimura 09/16/2015 @基研 21

Candidate ion: Pb^72+ (Ne-like) LHCで既にPb^82+を7TeV に加速済み

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m.yoshimura 09/16/2015 @基研 22

質量差による効果は大きい MD の区別は難しそう

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Neutrino mass determination

m.yoshimura 09/16/2015 @基研 23

Sensitivity to smallest 1 meV 10meV 10 meV 1 meV 5 meV 0,10,20 meV

光子とニュートリノ同時測定もできる

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Majorana/Dirac distinction in RENP

  • Difficult in the usual ways
  • Best is to discover doubly charged nu-nu events

: Lepton Number Violating (LNV) process

m.yoshimura 09/16/2015 @基研 24

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m.yoshimura 09/16/2015 @基研 25

rate computations at LHC to be done

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RENP using pair beam： まとめ

  • Absolute mass determination and MD distinction

expected

  • Kinematics different from SPAN: energy and

momentum conservation not obeyed, and only the energy sum of photon and two neutrinos limited

  • Rate scales with gamma^6

m.yoshimura 09/16/2015 @基研 26

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Comparisons

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開発実験研究

  • 量子重イオンビームの実現：

標的イオンの選定。対向照射レーザーの作成。 理研で低エネルギーイオンビームによるガンマ線またはX線放出を 測定するのがよい。（目標はコヒーラントガンマ線ビーム）

  • 現存LHCおよびそのアップグレードで何ができるか：

Pｂ原子核衝突を既に 7TeV で実現

  • 新たなFCC加速器の最適パラメータは？
  • 最適化した検出器の設計： e^+- の区別必要
  • 理論の協力が必要。

m.yoshimura 09/16/2015 @基研 28

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Another application of coherent quantum beam

  • When coherence exists between two levels related by E1 transition, exponential

cutoff of synchrotron radiation does not exist, and gamma ray energy is only limited by the same boosted level spacing

  • Coherence among many ions (macro-coherence) may lead to coherent gamma ray

beam (gamma ray “laser”)

m.yoshimura 09/16/2015 @基研 29

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Energy spectrum: comparison

m.yoshimura 09/16/2015 @基研 30

Synchrotron radiation

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Summary of this talk

  • We should maximally exploit quantum coherence

towards the ultimate clarification of mysteries of neutrino.

  • Coherent quantum heavy ion synchrotron is

excellent for the smallest mass measurement, NH/IH hierarchy distinction, MD distinction, and CPV parameter determination .

  • Accelerator R & D works crucial to obtain a high

coherence beam.

m.yoshimura 09/16/2015 @基研 31

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Backup

m.yoshimura 09/16/2015 @基研 32

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Neutrino pair beam and Neutrino oscillation experiments

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Differential and total production rates

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Only upper bound of total energy Extending to GeV region

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Detection of neutrino pair away from synchrotron

  • Single neutrino detection eliminates oscillation pattern

m.yoshimura 09/16/2015 @基研 35

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Short baseline experiments

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Plotted quantities Double rates

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m.yoshimura 09/16/2015 @基研 37

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How short baseline exp. became effective

  • Two factors of L/E, one 10km/10MeV instead
  • f 500km/500 MeV giving the same oscillation

pattern

m.yoshimura 09/16/2015 @基研 38

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m.yoshimura 09/16/2015 @基研 39

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Features of pair beam

  • Double detection required for oscillation

experiments

  • Short baseline experiments recommended to

avoid the earth matter effect

  • Excellent opportunity for ¥delta and NH/IH

m.yoshimura 09/16/2015 @基研 40

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Competition with QED photon emission

m.yoshimura 09/16/2015 @基研 41

  • >
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Pair emission build-up time should be shorter than 2nu production time.

m.yoshimura 09/16/2015 @基研 42