- Neutrino physics - PowerPoint PPT Presentation

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 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 m.yoshimura 09/16/2015 @ 基研 1

Present status of neutrino physics • Oscillation experiments – Finite mass – Flavor mixing – Only mass-squared difference can be measured. (Mass) sin 2 θ 13 ν 3 ν 2 } ∆ m 2 ν 1 sol ∆ m 2 atm = (50meV) 2 ν e |U ei | 2 ] or ∆ m 2 atm ν 2 ν µ [|U µ i | 2 ] } ∆ m 2 sol = (10 meV) 2 ν 1 ν 3 sin 2 θ 13 ν τ |U τ i | 2 ] 2 Normal (NH) Inverted (IH) m.yoshimura 09/16/2015 @ 基研

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. m.yoshimura 09/16/2015 @ 基研 3

Significance of Majorana neutrinos • Theoretical prejudice: Neutral leptons consist of 4 components like all other quarks and leptons, the ordinary massless neutrino and the other 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 4 m.yoshimura 09/16/2015 @ 基研

Majorana ｖｓ Dirac equations chirally projected solutions Dirac eq. ： degenerate 2 Majorana Particle annihilation Anti-particle creation 2-component in weak process involved Majorana eq. : particle=antiparticle 2 neutrino wave functions are anti-symmetrized m.yoshimura 09/16/2015 @ 基研 5

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 SPAN case m.yoshimura 09/16/2015 @ 基研 6

Pair emission probability after helicities summation: MD cases Common terms Majorana term m.yoshimura 09/16/2015 @ 基研 7

, ２． Lepton number violation can occur either in propagator or as a vertex Responsible in neutrino-less double beta decay, but see our examples below m.yoshimura 09/16/2015 @ 基研 8

References 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 Conventional neutrino sources: pi-, mu-, beta-decay We shall use de-excitation of circulating excited heavy ions, producing pairs of neutrino and anti-neutrino. m.yoshimura 09/16/2015 @ 基研 9

Quantum heavy ion beam 直線部分でレーザーを対向照射して励起 m.yoshimura 09/16/2015 @ 基研 10

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 光子数、光子エネルギー ともに指数関数減衰 neV x ¥gamma^3 m.yoshimura 09/16/2015 @ 基研 11

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 New feature for excited ions 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 m.yoshimura 09/16/2015 @ 基研 12

Prepa eparation on of of i ini nitial coher oheren ence – Adi diaba abatic R Ram aman an - ２つのレーザー照射 Two laser fields irradiates p-H2 Ω Ω + Σ u 1 B ≅ Ω g e Two photon Rabi frequency 11 eV ∆ ge ∆ |g> and |e> are mixed with an angle Ω θ ≅ ge tan δ 2.3 eV Non-degenerate Superposition States: θ θ + = + − ϕ i cos g sin e e 532nm 683nm 2 2 θ θ Ω Ω − = − − ϕ i cos g sin e e g e 2 2 Coherence between |e> and |g> δ = v 1 0.5 eV 1 ρ = θ “coherence” sin eg 2 = m.yoshimura 09/16/2015 @ 基研 13 0eV 0 v

p-H2 gas 532nm ± = θ = g 0 683nm θ θ ± = ± e − ϕ i cos g sin e 2 2 θ ≠ 0 π 1 1 ± = ± e − ϕ θ = i g e 2 2 2 θ θ e − ϕ ± = ± i cos g sin e 2 2 θ ≠ 0 ± = θ = g 0 m.yoshimura 09/16/2015 @ 基研 14

Two useful processes: pair emission and RENP (radiative neutrino pair emission) from circulating excited ions Neutrino-pair beam Beam RENP m.yoshimura 09/16/2015 @ 基研 15

How to calculate RENP emission rate • Semi-classical approximation: classical ion CM motion and quantum internal state • Spin current dominance from valence electron transition hamiltonian CP-even Mixture of well-defined phase coherence Spin factor －＞ Ion trajectory 16 m.yoshimura 09/16/2015 @ 基研

Some details of calculation m.yoshimura 09/16/2015 @ 基研 17

In the large radius (¥rho) limit 位相因子の積分で停留点近似を行う m.yoshimura 09/16/2015 @ 基研 18

Difference from usual synchrotron radiation Ground state ion X = rescaled time • Always the same sign phase added, leading to exponential dampling Excited ion with coherence Cancellation of positive and negative phases Energy input leads to resonance-like behavior 19 m.yoshimura 09/16/2015 @ 基研

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. Simple example of quantum coherence: adiabatic Raman process m.yoshimura 09/16/2015 @ 基研 20

Candidate ion: Pb^72+ (Ne-like) LHC で既に Pb^82+ を 7TeV に加速済み 21 m.yoshimura 09/16/2015 @ 基研

質量差による効果は大きい MD の区別は難しそう m.yoshimura 09/16/2015 @ 基研 22

Neutrino mass determination Sensitivity to smallest 1 meV 0,10,20 meV 5 meV 10 meV 10meV 1 meV 光子とニュートリノ同時測定もできる m.yoshimura 09/16/2015 @ 基研 23

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

rate computations at LHC to be done m.yoshimura 09/16/2015 @ 基研 25

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

Comparisons m.yoshimura 09/16/2015 @ 基研 27

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： • P ｂ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

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

Energy spectrum: comparison Synchrotron radiation m.yoshimura 09/16/2015 @ 基研 30

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

Backup m.yoshimura 09/16/2015 @ 基研 32

Neutrino pair beam and Neutrino oscillation experiments m.yoshimura 09/16/2015 @ 基研 33