DOCSLIB.ORG

Fermionic Supersymmetry in Time-Domain

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fermionic Supersymmetry in Time-Domain Fermionic Supersymmetry in Time-Domain Felipe A. Asenjo,1, ∗ Sergio A. Hojman,2, 3, 4, y Héctor M. Moya-Cessa,5, z and Francisco Soto-Eguibar5, x 1Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago 7491169, Chile. 2Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago 7491169, Chile. 3Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile. 4Centro de Recursos Educativos Avanzados, CREA, Santiago 7500018, Chile. 5Instituto Nacional de Astrofísica, Óptica y Electrónica. Calle Luis Enrique Erro No. 1, Santa María Tonantzintla, Puebla 72840, Mexico. A supersymmetric theory in the temporal domain is constructed for bi-spinor fields satisfying the Dirac equation. It is shown that using the Dirac matrices basis, it is possible to construct a simple time-domain supersymmetry for fermion fields with time-dependent mass. This theory is equivalent to a bosonic supersymmetric theory in the time-domain. Solutions are presented, and it is shown that they produce probability oscillations between its spinor mass states. This theory is applied to the two-neutrino oscillation problem, showing that the flavour state oscillations emerge from the supersymmetry originated by the time-dependence of the unique mass of the neutrino. It is shown that the usual result for the two-neutrino oscillation problem is recovered in the short-time limit of this theory. Finally, it is discussed that this time-domain fermionic supersymmetric theory cannot be obtained in the Majorana matrices basis, thus giving hints on the Dirac fermion nature of neutrinos. PACS numbers: Keywords: I. INTRODUCTION tum mechanics for fermions described by the Dirac equa- tion. In this case, we show that the simplest T-SUSY Supersymmetry is one of the cornerstones of theoreti- theory can be constructed for Dirac fermions with time- cal physics [1], being ubiquitous in almost every branch dependent mass, i.e, using the Dirac matrices basis. of physics [2–24]. We completly develop this fermionic T-SUSY theory, finding solutions for different possible time-dependent The standard way to proceed is to construct super- masses. This theory is equivalent to its bosonic partner, symmetric theories in a space-domain, where the super- allowing us to obtain a massive fermion field behavior partners and supercharge operators take into account the which is analogue to a light-like one. spatial variations of, for example, external potentials. In Besides, this theory produces probability states oscilla- this work, it is not our aim to focus in those spatial super- tions, and thus can be used to study the neutrino oscilla- symmetries, but instead, to inquire if a temporal version tion problem. In this way, we give a different perspective of such theories is possible for massive fields [25]. to the origin of neutrino oscillations through supersym- Recently, García-Meca, Macho Ortiz and Lorrente metry in the time-domain. Sáez [25] have introduced the concept of supersymmetry We end our proposal by showing the impossibility to in time-domain (T-SUSY) for Maxwell equations. This implement this temporal supersymmetry in the Majo- is a supersymmetry occurring in the temporal part of the rana basis. Therefore, this theory discerns between Dirac massless field dynamics, completely uncoupled from the and Majorana neutrinos. spatial evolution of the field. They studied the appli- cations of T-SUSY in the realm of optics for dispersive media, showing the novel capabilities of this theory to II. T-SUSY FOR DIRAC FERMIONS arXiv:2012.11024v1 [quant-ph] 20 Dec 2020 introduce hypothetical materials with new optical fea- tures. Besides, they show that this time-domain super- Let us consider a bi-spinor field (satisfying the Dirac symmetry applies to any field described, in principle, by a equation in flat spacetime) with the form d’Alambertian equation. In other words, they developed the bosonic version of the T-SUSY theory. e Ψ = + + ; (1) It is the purpose of this manuscript to show that a −e− T-SUSY theory can also be obtained in relativistic quan- in terms of wavefunctions + and −, and the spinors 1 0 e = ; e = ; (2) + 0 − 1 ∗Electronic address: [email protected] yElectronic address: [email protected] y y y zElectronic address: [email protected] with the properties e+e+ = 1 = e−e−, and e+e− = 0 = x y Electronic address: [email protected] e−e+. 2 The simplest form of a T-SUSY theory can be obtained where E± are complex time-dependent functions that from field propagation in one spatial dimension. In this satisfy the Ricatti equation form, the Dirac equation in flat spacetime for a massive dE fermion field Ψ reads i ± − E2 + k2 = W ; (11) dt ± ± 0 1 iγ @0Ψ + iγ @1Ψ = mΨ ; (3) such that ±(0) = 1. Whenever dm=dt 6= 0, then E+ 6= where m is the mass of the field. Besides, @0 is a time E−. In this way, for a specific time functionality of the derivative and @1 is a space derivative in an arbitrary di- mass, solutions for E± can be found in order to satisfy rection. As always, Dirac matrices fulfill γµγν + γν γµ = this T-SUSY description. µν µν 2η 14×4, where the metric is η = (1; −1; −1; −1), and All the framework for a standard supersymmetric the- 14×4 is the identity matrix in this four-dimensional space- ory in quantum mechanics can be straightforwardly uti- time. lized for this T-SUSY theory. For example, its algebra is In order to evaluate explicitly the T-SUSY theory for defined by the matrix operators fermions, let us choose the following Dirac matrices H 0 0 0 0 Q H = + ; Q = ; Qy = − ; 0 1 0 0 0 1 0 0 0 0 1 1 0 H− Q+ 0 0 0 0 1 0 0 0 0 1 0 γ0 = B C ; γ1 = B C : (4) (12) @ 0 0 −1 0 A @ 0 −1 0 0 A that have the closed algebra H = fQ; Qyg, [H; Q] = 0 = 0 0 0 −1 −1 0 0 0 [H; Qy], fQ; Qg = 0 = fQy; Qyg, for the bosonic H and fermionic Q and Qy operators. Now, in order to decouple the space dynamics, let us as- Finally, we notice that this fermionic T-SUSY theory sume that @ Ψ = ikΨ with an arbitrary constant k. This 1 can be put in analogue fashion to its bosonic counterpart k plays the role of the constant momentum of the fermion developed in Ref. [25]. We can rewrite Eq. (7) in the propagation. In this way, under this representation, we form find that Eq. (3) becomes simply d2 1 Q± ± = k ∓ ; (5) 2 + 2 ± = 0 ; (13) dt n± in terms of supercharge operators where d 2 −1=2 Q± = i ∓ m ; (6) n (t) = k − W : (14) dt ± ± where now d=dt is a total time derivative. Eqs. (5) corre- Eq. (13) is equivalent to the one describing the propaga- spond to a set of supersymmetric equations of quantum tion of light in a medium with supersymmetric refraction mechanics, now obtained in the Dirac matrices basis (4). indices n±. In this T-SUSY theory, both refraction in- Notice that, then, the simplest T-SUSY theory requires dices are related by that the mass be the responsible for the origin of the su- −1=2 perpotential of this supersymmetry. This occurs when 1 dm n+ = 2 + 2i : (15) the mass becomes time-dependent, m = m(t). n− dt Eqs. (5) can be used to calculate the equations that This relation shows the equivalence of fermionic T-SUSY each wavefunction ± satisfies. They are with bosonic T-SUSY discussed in Ref. [25] 2 H± ± = k ± ; (7) where we have defined the super-Hamiltonians H± in III. SIMPLE SOLUTIONS terms of superpotentials W± as d2 We can get simple solutions for fermion fields with H = Q Q = − + W ; (8) ± ∓ ± dt2 ± time-dependent mass. Let us first consider the simple solution for the massive where case, when k n m(t). For this case, from Eq. (11), we dm find W = ∓i − m2 ; (9) ± dt E±(t) ≈ ∓m(t) : (16) such that W− − W+ = 2i dm=dt. Thereby, the difference between states lies in the time dependence of the mass. Therefore, the two mass states have different behavior In general, from Eq. (7), we can write the wavefunc- stemming from just one time-dependent mass. tions (1) as Similarly, another simple solution can be obtained in the light-mass (ultra-relativistic) case, when k m(t). Z For this case, k corresponds (approximately) to the en- ±(t) = exp i dt E± ; (10) ergy of the particle. Let us assume that m(t) = m0 +(t), 3 p 2 2 with a constant m0 , and E±(t) = k + m0 + δ± ≈ supersymmetry due to the temporal dependence of the k + δ±(t), such that δ±(t) k. In this case, Eq. (11) mass. becomes Considering the bi-spinor (1), let us define a bi-spinor with mixed states dδ± d i − 2kδ± = ∓i − 2m0 : (17) Φ dt dt Φ = a = U Ψ ; (22) Φb By writing δ± = δR± + iδI± (with δR± and δI± reals), with the spinor wavefunctions Φa and Φb defining new then we find dδR±=dt − 2kδI± = ∓d/dt, and dδI±=dt + 2kδ = 2m . This set gives the equation states. Here, U is a unitary matrix with role of mixing R± 0 states. It can be written as [26–29] 2 2 d δR± d 2 cos θ 12×2 sin θ 12×2 2 + 4k δR± = ∓ 2 + 4km0 ; (18) U = ; (23) dt dt − sin θ 12×2 cos θ 12×2 which allow us to find the solutions where θ is called the mixing angle in vacuum, and 12×2 is the 2 × 2 identity matrix.
Load more

Recommended publications
  • Jongkuk Kim Neutrino Oscillations in Dark Matter
    Neutrino Oscillations in Dark Matter Jongkuk Kim Based on PRD 99, 083018 (2019), Ki-Young Choi, JKK, Carsten Rott Based on arXiv: 1909.10478, Ki-Young Choi, Eung Jin Chun, JKK 2019. 10. 10 @ CERN, Swiss Contents Neutrino oscillation MSW effect Neutrino-DM interaction General formula Dark NSI effect Dark Matter Assisted Neutrino Oscillation New constraint on neutrino-DM scattering Conclusions 2 Standard MSW effect Consider neutrino/anti-neutrino propagation in a general background electron, positron Coherent forward scattering 3 Standard MSW effect Generalized matter potential Standard matter potential L. Wolfenstein, 1978 S. P. Mikheyev, A. Smirnov, 1985 D d Matter potential @ high energy d 4 General formulation Equation of motion in the momentum space : corrections R. F. Sawyer, 1999 P. Q. Hung, 2000 A. Berlin, 2016 In a Lorenz invariant medium: S. F. Ge, S. Parke, 2019 H. Davoudiasl, G. Mohlabeng, M. Sulliovan, 2019 G. D’Amico, T. Hamill, N. Kaloper, 2018 d F. Capozzi, I. Shoemaker, L. Vecchi 2018 Canonical basis of the kinetic term: 5 General formulation The Equation of Motion Correction to the neutrino mass matrix Original mass term is modified For large parameter space, the mass correction is subdominant 6 DM model Bosonic DM (ϕ) and fermionic messenger (푋푖) Lagrangian Coherent forward scattering 7 General formulation Ki-Young Choi, Eung Jin Chun, JKK Neutrino/ anti-neutrino Hamiltonian Corrections 8 Neutrino potential Ki-Young Choi, Eung Jin Chun, JKK Change of shape: Low Energy Limit: High Energy limit: 9 Two-flavor oscillation The effective Hamiltonian D The mixing angle & mass squared difference in the medium 10 Mass difference between ν&νҧ Ki-Young Choi, Eung Jin Chun, JKK I Bound: T.
    [Show full text]
  • QUANTUM GRAVITY EFFECT on NEUTRINO OSCILLATION Jonathan Miller Universidad Tecnica Federico Santa Maria
    QUANTUM GRAVITY EFFECT ON NEUTRINO OSCILLATION Jonathan Miller Universidad Tecnica Federico Santa Maria ARXIV 1305.4430 (Collaborator Roman Pasechnik) !1 INTRODUCTION Neutrinos are ideal probes of distant ‘laboratories’ as they interact only via the weak and gravitational forces. 3 of 4 forces can be described in QFT framework, 1 (Gravity) is missing (and exp. evidence is missing): semi-classical theory is the best understood 2 38 2 graviton interactions suppressed by (MPl ) ~10 GeV Many sources of astrophysical neutrinos (SNe, GRB, ..) Neutrino states during propagation are different from neutrino states during (weak) interactions !2 SEMI-CLASSICAL QUANTUM GRAVITY Class. Quantum Grav. 27 (2010) 145012 Considered in the limit where one mass is much greater than all other scales of the system. Considered in the long range limit. Up to loop level, semi-classical quantum gravity and effective quantum gravity are equivalent. Produced useful results (Hawking/etc). Tree level approximation. gˆµ⌫ = ⌘µ⌫ + hˆµ⌫ !3 CLASSICAL NEUTRINO OSCILLATION Neutrino Oscillation observed due to Interaction (weak) - Propagation (Inertia) - Interaction (weak) Neutrino oscillation depends both on production and detection hamiltonians. Neutrinos propagates as superposition of mass states. 2 2 2 mj mk ∆m L iEat ⌫f (t) >= Vfae− ⌫a > φjk = − L = | | 2E⌫ 4E⌫ a X 2 m m2 i j L i k L 2E⌫ 2E⌫ P⌫f ⌫ (E,L)= Vf 0jVf 0ke− e Vfj⇤ Vfk⇤ ! f0 j,k X !4 MATTER EFFECT neutrinos interact due to flavor (via W/Z) with particles (leptons, quarks) as flavor eigenstates MSW effect: neutrinos passing through matter change oscillation characteristics due to change in electroweak potential effects electron neutrino component of mass states only, due to electrons in normal matter neutrino may be in mass eigenstate after MSW effect: resonance Expectation of asymmetry for earth MSW effect in Solar neutrinos is ~3% for current experiments.
    [Show full text]
  • Neutrino Physics
    SLAC Summer Institute on Particle Physics (SSI04), Aug. 2-13, 2004 Neutrino Physics Boris Kayser Fermilab, Batavia IL 60510, USA Thanks to compelling evidence that neutrinos can change flavor, we now know that they have nonzero masses, and that leptons mix. In these lectures, we explain the physics of neutrino flavor change, both in vacuum and in matter. Then, we describe what the flavor-change data have taught us about neutrinos. Finally, we consider some of the questions raised by the discovery of neutrino mass, explaining why these questions are so interesting, and how they might be answered experimentally, 1. PHYSICS OF NEUTRINO OSCILLATION 1.1. Introduction There has been a breakthrough in neutrino physics. It has been discovered that neutrinos have nonzero masses, and that leptons mix. The evidence for masses and mixing is the observation that neutrinos can change from one type, or “flavor”, to another. In this first section of these lectures, we will explain the physics of neutrino flavor change, or “oscillation”, as it is called. We will treat oscillation both in vacuum and in matter, and see why it implies masses and mixing. That neutrinos have masses means that there is a spectrum of neutrino mass eigenstates νi, i = 1, 2,..., each with + a mass mi. What leptonic mixing means may be understood by considering the leptonic decays W → νi + `α of the W boson. Here, α = e, µ, or τ, and `e is the electron, `µ the muon, and `τ the tau. The particle `α is referred to as the charged lepton of flavor α.
    [Show full text]
  • Peering Into the Universe and Its Ele Mentary
    A gigantic detector to explore elementary particle unification theories and the mysteries of the Universe’s evolution Peering into the Universe and its ele mentary particles from underground Ultrasensitive Photodetectors The planned Hyper-Kamiokande detector will consist of an Unified Theory and explain the evolution of the Universe order of magnitude larger tank than the predecessor, Super- through the investigation of proton decay, CP violation (the We have been developing the world’s largest photosensors, which exhibit a photodetection Kamiokande, and will be equipped with ultra high sensitivity difference between neutrinos and antineutrinos), and the efficiency two times greater than that of the photosensors. The Hyper-Kamiokande detector is both a observation of neutrinos from supernova explosions. The Super-Kamiokande photosensors. These new “microscope,” used to observe elementary particles, and a Hyper-Kamiokande experiment is an international research photosensors are able to perform light intensity “telescope”, used to study the Sun and supernovas through project aiming to become operational in the second half of and timing measurements with a much higher neutrinos. Hyper-Kamiokande aims to elucidate the Grand the 2020s. precision. The new Large-Aperture High-Sensitivity Hybrid Photodetector (left), the new Large-Aperture High-Sensitivity Photomultiplier Tube (right). The bottom photographs show the electron multiplication component. A megaton water tank The huge Hyper-Kamiokande tank will be used in order to obtain in only 10 years an amount of data corresponding to 100 years of data collection time using Super-Kamiokande. This Experimental Technique allows the observation of previously unrevealed The photosensors on the tank wall detect the very weak Cherenkov rare phenomena and small values of CP light emitted along its direction of travel by a charged particle violation.
    [Show full text]
  • INO/ICAL/PHY/NOTE/2015-01 Arxiv:1505.07380 [Physics.Ins-Det]
    INO/ICAL/PHY/NOTE/2015-01 ArXiv:1505.07380 [physics.ins-det] Pramana - J Phys (2017) 88 : 79 doi:10.1007/s12043-017-1373-4 Physics Potential of the ICAL detector at the India-based Neutrino Observatory (INO) The ICAL Collaboration arXiv:1505.07380v2 [physics.ins-det] 9 May 2017 Physics Potential of ICAL at INO [The ICAL Collaboration] Shakeel Ahmed, M. Sajjad Athar, Rashid Hasan, Mohammad Salim, S. K. Singh Aligarh Muslim University, Aligarh 202001, India S. S. R. Inbanathan The American College, Madurai 625002, India Venktesh Singh, V. S. Subrahmanyam Banaras Hindu University, Varanasi 221005, India Shiba Prasad BeheraHB, Vinay B. Chandratre, Nitali DashHB, Vivek M. DatarVD, V. K. S. KashyapHB, Ajit K. Mohanty, Lalit M. Pant Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India Animesh ChatterjeeAC;HB, Sandhya Choubey, Raj Gandhi, Anushree GhoshAG;HB, Deepak TiwariHB Harish Chandra Research Institute, Jhunsi, Allahabad 211019, India Ali AjmiHB, S. Uma Sankar Indian Institute of Technology Bombay, Powai, Mumbai 400076, India Prafulla Behera, Aleena Chacko, Sadiq Jafer, James Libby, K. RaveendrababuHB, K. R. Rebin Indian Institute of Technology Madras, Chennai 600036, India D. Indumathi, K. MeghnaHB, S. M. LakshmiHB, M. V. N. Murthy, Sumanta PalSP;HB, G. RajasekaranGR, Nita Sinha Institute of Mathematical Sciences, Taramani, Chennai 600113, India Sanjib Kumar Agarwalla, Amina KhatunHB Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India Poonam Mehta Jawaharlal Nehru University, New Delhi 110067, India Vipin Bhatnagar, R. Kanishka, A. Kumar, J. S. Shahi, J. B. Singh Panjab University, Chandigarh 160014, India Monojit GhoshMG, Pomita GhoshalPG, Srubabati Goswami, Chandan GuptaHB, Sushant RautSR Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India Sudeb Bhattacharya, Suvendu Bose, Ambar Ghosal, Abhik JashHB, Kamalesh Kar, Debasish Majumdar, Nayana Majumdar, Supratik Mukhopadhyay, Satyajit Saha Saha Institute of Nuclear Physics, Bidhannagar, Kolkata 700064, India B.
    [Show full text]
  • Neutrino Mixing 34 5.1 Three-Neutrino Mixing Schemes
    hep-ph/0310238 Neutrino Mixing Carlo Giunti INFN, Sezione di Torino, and Dipartimento di Fisica Teorica, Universit`adi Torino, Via P. Giuria 1, I–10125 Torino, Italy Marco Laveder Dipartimento di Fisica “G. Galilei”, Universit`adi Padova, and INFN, Sezione di Padova, Via F. Marzolo 8, I–35131 Padova, Italy Abstract In this review we present the main features of the current status of neutrino physics. After a review of the theory of neutrino mixing and oscillations, we discuss the current status of solar and atmospheric neu- trino oscillation experiments. We show that the current data can be nicely accommodated in the framework of three-neutrino mixing. We discuss also the problem of the determination of the absolute neutrino mass scale through Tritium β-decay experiments and astrophysical ob- servations, and the exploration of the Majorana nature of massive neu- trinos through neutrinoless double-β decay experiments. Finally, future prospects are briefly discussed. PACS Numbers: 14.60.Pq, 14.60.Lm, 26.65.+t, 96.40.Tv Keywords: Neutrino Mass, Neutrino Mixing, Solar Neutrinos, Atmospheric Neutrinos arXiv:hep-ph/0310238v2 1 Oct 2004 1 Contents Contents 2 1 Introduction 3 2 Neutrino masses and mixing 3 2.1 Diracmassterm................................ 4 2.2 Majoranamassterm ............................. 4 2.3 Dirac-Majoranamassterm. 5 2.4 Thesee-sawmechanism ........................... 7 2.5 Effective dimension-five operator . ... 8 2.6 Three-neutrinomixing . 9 3 Theory of neutrino oscillations 13 3.1 Neutrino oscillations in vacuum . ... 13 3.2 Neutrinooscillationsinmatter. .... 17 4 Neutrino oscillation experiments 25 4.1 Solar neutrino experiments and KamLAND . .. 26 4.2 Atmospheric neutrino experiments and K2K .
    [Show full text]
  • India-Based Neutrino Observatory (Ino)
    INDIAINDIA--BASEDBASED NEUTRINONEUTRINO OBSERVATORYOBSERVATORY (INO)(INO) PlansPlans && StatusStatus NabaNaba KK MondalMondal Tata Institute of Fundamental Research Mumbai, India AtmosphericAtmospheric neutrinoneutrino detectiondetection inin 19651965 Physics Letters 18, (1965) 196, dated 15th Aug 1965 Atmospheric neutrino detector at Kolar Gold Field –1965 INO-UKNF meeting4th April, 2008PRL 15, (1965), 429, dated 30th Aug. 1965 2 KGFKGF INO-UKNF meeting4th April, 2008 3 INOINO InitiativeInitiative • In early 2002, a document was presented to the Dept. of Atomic Energy (DAE), Govt of India with a request for fund to carry out feasibility study for setting up an underground neutrino laboratory in India. • In August 2002, an MoU was signed by the directors of seven participating DAE institutes towards working together on the feasibility study for such a laboratory. • A neutrino collaboration group was established with members mostly from Indian Institutes and Universities. • A sum of 50 million INR ( 1 M USD) was allotted by DAE to carry out the feasibility study. • Considering the physics possibilities and given the past experience at Kolar, it was agreed to carry out the feasibility study for a large mass magnetised iron calorimeter which will compliment the already existing water cherenkov based Super-K experiment in Japan. INO-UKNF meeting4th April, 2008 4 INOINO activitiesactivities duringduring feasibilityfeasibility studystudy periodperiod •• DetectorDetector RR && D:D: •• SiteSite Survey:Survey: – Choice of active detector – History
    [Show full text]
  • Future Hadron Physics at Fermilab
    Future Hadron Physics at Fermilab Jeffrey A. Appel Fermi National Accelerator Laboratory PO Box 500, Batavia, IL 60510 USA [email protected] Abstract. Today, hadron physics research occurs at Fermilab as parts of broader experimental programs. This is very likely to be the case in the future. Thus, much of this presentation focuses on our vision of that future – a future aimed at making Fermilab the host laboratory for the International Linear Collider (ILC). Given the uncertainties associated with the ILC - the level of needed R&D, the ILC costs, and the timing - Fermilab is also preparing for other program choices. I will describe these latter efforts, efforts focused on a Proton Driver to increase the numbers of protons available for experiments. As examples of the hadron physics which will be coming from Fermilab, I summarize three experiments: MIPP/E907 which is running currently, and MINERνA and Drell-Yan/E906 which are scheduled for future running periods. Hadron physics coming from the Tevatron Collider program will be summarized by Arthur Maciel in another talk at Hadron05. Keywords: Fermilab, Tevatron, ILC, hadron, MIPP, MINERνA, Drell-Yan, proton driver. PACS: 13.85.-t INTRODUCTION In order to envisage the future of hadron physics at Fermilab, it will be useful to know the research context at the Laboratory. That can be best done by looking at the recent presentations by Fermilab's new Director, Piermaria Oddone, who began his tenure as Director on July 1, 2005. Pier has had several opportunities to project the vision of Fermilab's future, both inside the Laboratory and to outside committees.1 I draw heavily on his presentations.
    [Show full text]
  • Neutrino Physics and the Mirror World: How Exact Parity Symmetry Explains the Solar Neutrino Deficit, the Atmospheric Neutrino Anomaly and the LSND Experiment
    May 1995 UM-P-95/49 RCHEP-95/14 Neutrino physics and the mirror world: How exact parity symmetry explains the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experiment R. Foot and R. R. Volkas Research Centre for High Energy Physics School of Physics University of Melbourne Parkville 3052 Australia Abstract Evidence for V11 -» vt oscillations has been reported at LAMPF using the LSND detector. Further evidence for neutrino mixing comes from the solar neutrino deficit and the atmospheric neutrino anomaly. All of these anomalies require new physics. We show that all of these anomalies can be explained if the standard model is en- larged so that an unbroken parity symmetry can be defined. This explanation holds independently of the actual model for neutrino masses. Thus, we argue that parity symmetry is not only a beautiful candidate for a symmetry beyond the standard model, but it can also explain the known neutrino physics anomalies. VOL 2 7 Nl 0 6 I Introduction Recently, the LSND Collaboration has found evidence for D11 —»• i/e oscillations [I]. If the anomaly in this experiment is interpreted as neutrino oscillations, then they obtain the range of parameters Am2 ~ 3 — 0.2 eV2 and sin2 29 ~ 3 x 10~2 — 10~3. If the interpretation of this experiment is correct then it will lead to important ramifications for particle physics and cosmology. In addition to the direct experimental anomaly discussed above, and the theo- retical argument for non-zero neutrino masses from the observed electric charges oi the known particles [2], there are two indirect indications that the minimal standard model is incomplete.
    [Show full text]
  • Neutrino Oscillation Studies with Reactors
    REVIEW Received 3 Nov 2014 | Accepted 17 Mar 2015 | Published 27 Apr 2015 DOI: 10.1038/ncomms7935 OPEN Neutrino oscillation studies with reactors P. Vogel1, L.J. Wen2 & C. Zhang3 Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well- understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle y13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos. eutrinos, the products of radioactive decay among other things, are somewhat enigmatic, since they can travel enormous distances through matter without interacting even once. NUnderstanding their properties in detail is fundamentally important. Notwithstanding that they are so very difficult to observe, great progress in this field has been achieved in recent decades. The study of neutrinos is opening a path for the generalization of the so-called Standard Model that explains most of what we know about elementary particles and their interactions, but in the view of most physicists is incomplete. The Standard Model of electroweak interactions, developed in late 1960s, incorporates À À neutrinos (ne, nm, nt) as left-handed partners of the three families of charged leptons (e , m , t À ). Since weak interactions are the only way neutrinos interact with anything, the un-needed right-handed components of the neutrino field are absent in the Model by definition and neutrinos are assumed to be massless, with the individual lepton number (that is, the number of leptons of a given flavour or family) being strictly conserved.
    [Show full text]
  • Neutrino Oscillations
    Neutrino Oscillations Inês Terrucha Marta Reis Instituto Superior Técnico Hands on Quantum Mechanics 23 de Julho de 2015 A little bit of History 1899 - Nuclear β decay was discovered by E.Rutherford 1991 - Lise Meitner and Otto Hahn performed an experiment showing that the energies of electrons emitted by beta decay had a continuous rather than discrete spectrum. 1930 - W.Pauli suggested that in addition to electrons and protons, it was also emited an extremely light neutral particle which he called the ’neutron’ − n ! p + e + νe 1932 - E.Chadwick discovered the neutron 1934 - Enrico Fermi renamed Pauli’s ’neutron’ to neutrino 1956 - Discovery of a particle fitting the expected characteristics of the neutrino is announced by Clyde Cowan and Fred Reines. This neutrino is later determined to be the partner of the electron 1962- Discovery of the muon neutrino at Brookhaven National Laboratory and CERN 1968 - Discovery of the electron neutrino produced by the Sun 1978 - Discovery of the tau lepton at SLAC, existence of tau neutrino theorized 2000 - Discovery of the tau neutrino by the DONUT collaboration Neutrinos in the Standard Model I Zero mass I Come in three flavors I Each flavor is also associated with an antiparticle, called an antineutrino, which also has no electric charge and half-integer spin I All neutrinos are left-handed, and all I Electrically neutral antineutrinos are I Half-integer spin right-handed. Neutrinos in the Standard Model I Neutrinos do not carry any electric charge so they are not affected by the electromagnetic force that acts on charged particles Neutrinos in the Standard Model I Since they are leptons they are not affected by the strong force that acts on particles inside atomic nuclei Neutrinos in the Standard Model I Neutrinos are therefore affected only by the weak subatomic force.
    [Show full text]
  • Predictive Theory of Neutrino Masses
    PREDICTIVE THEORY OF NEUTRINO MASSES Olakanmi F. Akinto *,†,‡ and Farida Tahir *,# *Department of Physics, COMSATS University Islamabad, Pakistan †Department of Physics, National Mathematical Centre, Sheda-Kwali Abuja, Nigeria ‡[email protected] #[email protected] In our recent paper [1] we formulated a predictive theory of neutrino masses by considering the interaction between the infrared sector of the effective theory of quantum gravity and the standard model fields. This allowed us to calculate, for the first time in the history of neutrino physics, the absolute scale of neutrino masses. From this theoretical framework, we obtained quantum-gravitational couplings/effective Majorana dimensionless couplings from the spherically symmetric vacuum solutions arising from the Bose-Einstein statistical modification to gravitation. In the present paper, we show that the same solutions can be obtained directly from the quantum interpretation of gravitational radiation arising from the thermodynamic modification to gravitation. Within this theoretical scheme, we show that the single-field inflationary model, GUTs, dark energy and matter-independent gravitational field of vacuum are all connected to the neutrino mass model. Keywords: Neutrino masses, GUTs, quantum gravity I. INTRODUCTION trajectories across the universe. This property makes neutrinos the most eloquent footprint of Neutrinos have been around, literally, since the a possible quantum-classical nature of gravity, beginning of time. In the sweltering moments representing
    [Show full text]