Solar neutrino spectroscopy

Since the pioneering experiment of R. Davis et al., which started neutrino astronomy by measuring the solar neutrinos via the inverse beta decay reaction on ³⁷Cl, all solar neutrino experiments find a considerably lower flux than expected by standard solar models. This finding is generally called the solar neutrino problem. Many attempts have been made to explain this result by altering the solar models, or assuming different nuclear cross sections for fusion processes assumed to be the energy sources in the sun.There have been performed numerous experiments recently to investigate the different possibilities to explain the solar neutrino problem. These experiments covered solar physics with helioseismology, nuclear cross section measurements, and solar neutrino experiments.Up to now no convincing explanation based on “standard” physics was suggested. However, assuming nonstandard neutrino properties, i.e. neutrino masses and mixing as expected in most extensions of the standard theory of elementary particle physics, natural solutions for the solar neutrino problem can be found.It appears that with this newly invented neutrino astronomy fundamental information on astrophysics as well as elementary particle physics are tested uniquely. In this contribution an attempt is made to review the situation of the neutrino astronomy for solar neutrino spectroscopy and discuss the future prospects in this field.     

A short review of most interesting recent results in neutrino physics

This lecture presented at the Baikal summer school on physics of elementary particles and astrophysics in 2011 is devoted to review recent hot results in neutrino physics.     

Introduction to neutrino physics

A synopsis of lectures is presented which were delivered by the author in 2010 at the Baikal summer school on physics of elementary particles and astrophysics. The lectures are primarily intended for students, postgraduates, and young researchers as an introductory course on neutrino physics.     

Identity of Elementary Particles and Gauge Interactions

Problems of gauge invariance and identity of elementary particles are examined. The hypothesis that the gauge field charge is related to the possible increase of the entropy is set up. It is demonstrated that the given hypothesis allows fundamental interactions to be interrelated and numerical relations for elementary particle masses to be derived. Theoretical and practical consequences of the examined hypothesis are discussed.     

Making the universe safe for historians: Time travel and the laws of physics

The study of the hypothetical activities of arbitrarily advanced cultures, particularly in the area of space and time travel, as a means of investigating fundamental issues in physics is briefly discussed. Hawking's chronology protection conjecture as it applies to wormhole spacetimes is considered. The nature of time, especially regarding the viability of time travel, as it appears in several interpretations of quantum mechanics is investigated. A conjecture on the plausibility of theories of reality that admit relativistically invariant interactions and irreducibly stochastic processes is advanced. A transient inertial reaction effect that makes it technically feasible, fleetingly, to induce large concentrations of negative mass-energy is presented and discussed in the context of macroscopic wormhole formation. Other candidates for chronology protection are examined. It is pointed out that if the strong version of Mach's principle (the gravitational induction of mass) is correct, then wormhole formation employing negative mass-energy is impossible. But if the bare masses of elementary particles are large, finite and negative, as is suggested by a heuristic general relativistic model of elementary particles, then, using the transient effect, it is technically feasible to trigger a non-linear process that may lead to macroscopic wormhole formation. Such wormholes need not be destroyed by the Hawking protection mechanism.     

Gauge theory of massless spin-(3/2) field in de Sitter space-time

On several levels of theoretical physics, especially particle physics and early universe cosmology, de Sitter space-time has become an attractive possibility. The principle of local gauge invariance governs all known fundamental interactions of elementary particles, from electromagnetism and weak interactions to strong interactions and gravity. This paper presents a procedure for defining the gauge-covariant derivative and gauge invariant Lagrangian density in de Sitter ambient space-time formalism. The gauge invariant field equation is then explicitly calculated in detail for a massless spin-(3/2) gauge field.     

The Joint Institute for Nuclear Research in Experimental Physics of Elementary Particles

The year 2016 marks the 60th anniversary of the Joint Institute for Nuclear Research (JINR) in Dubna, an international intergovernmental organization for basic research in the fields of elementary particles, atomic nuclei, and condensed matter. Highly productive advances over this long road clearly show that the international basis and diversity of research guarantees successful development (and maintenance) of fundamental science. This is especially important for experimental research. In this review, the most significant achievements are briefly described with an attempt to look into the future (seven to ten years ahead) and show the role of JINR in solution of highly important problems in elementary particle physics, which is a fundamental field of modern natural sciences. This glimpse of the future is full of justified optimism.     

Neutrinos: precursors of new physics

Since neutrinos are the only elementary particles that interact only weakly, the study of their properties, albeit experimentally difficult, reflects the true nature of the Weak Interactions. We begin with a historical review, emphasizing the central role of neutrinos in the formulation of the Standard Model. We review the generalizations of the Standard Model needed to accommodate both Dirac and Majorana neutrino masses. The recent experimental findings which demonstrate that neutrinos have tiny masses are discussed. We argue that small neutrino masses as well as the unexpected mixing patterns between the three neutrino flavors give us a glimpse, through the Seesaw mechanism, of physics at or near the Planck scale. To cite this article: P. Ramond, C. R. Physique 6 (2005).     

Fundamental theories of waves and particles formulated without classical mass

Quantum and classical mechanics are two conceptually and mathematically different theories of physics, and yet they do use the same concept of classical mass that was originally introduced by Newton in his formulation of the laws of dynamics. In this paper, physical consequences of using the classical mass by both theories are explored, and a novel approach that allows formulating fundamental (Galilean invariant) theories of waves and particles without formally introducing the classical mass is presented. In this new formulation, the theories depend only on one common parameter called ‘wave mass’, which is deduced from experiments for selected elementary particles and for the classical mass of one kilogram. It is shown that quantum theory with the wave mass is independent of the Planck constant and that higher accuracy of performing calculations can be attained by such theory. Natural units in connection with the presented approach are also discussed and justification beyond dimensional analysis is given for the particular choice of such units.     

Higgs models

This lecture presented at the Baikal summer school on physics of elementary particles and astrophysics in 2011 is devoted to the Higgs mechanism of the electroweak symmetry breaking within the Standard Model and in some models beyond it.     

Precision mass measurements of neutron halo nuclei using the TITAN Penning trap

Precise atomic mass determinations play a key role in various fields of physics, including nuclear physics, testing of fundamental symmetries and constants and atomic physics. Recently, the TITAN Penning trap measured the masses of several neutron halos. These exotic systems have an extended, diluted, matter distribution that can be modelled by considering a nuclear core surrounded by a halo formed by one or more of loosely bound neutrons. Combined with laser spectroscopy measurements of isotopic shifts precise masses can be used to obtain reliable charge radii and two-neutron-seperation energies for these halo nuclei. It is shown that these results can be used as stringent tests of nuclear models and potentials providing an important metric for our understanding of the interactions in all nuclei.     

Atmospheric neutrinos and discovery of neutrino oscillations

Neutrino oscillation was discovered through studies of neutrinos produced by cosmic-ray interactions in the atmosphere. These neutrinos are called atmospheric neutrinos. They are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith-angle and energy dependent deficit of muon-neutrino events. Neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. Neutrino oscillations imply that neutrinos have small but non-zero masses. The small neutrino masses have profound implications to our understanding of elementary particle physics and the Universe. This article discusses the experimental discovery of neutrino oscillations.     

Use of internal targets for investigations of accelerated-particle beams in atomic physics

The methods of experiments in atomic physics with linear and cyclic accelerators and in external particle beams with the use of various internal targets (corpuscular, photon, and in the form of spatially localized electromagnetic fields) are reviewed. The features of forming secondary particles coming from the beam and measurements of cross sections for elementary processes are described. Examples of generating various charge and quantum states of beam particles and investigations using them based on targets of a different kind separated or superimposed on the path length are given. It is shown that the atomic processes proceeding in this case can be controlled by applying appropriate electric, magnetic, and electromagnetic fields in the interaction region.     

Triviality pursuit: Can elementary scalar particles exist?

Great effort is presently being expended in the search for elementary scalar “Higgs” particles. These particles have yet to be observed. The primary justification for this search is the theoretically elegant Higgs-Kibble mechanism, in which the interactions of elemetary scalars are used to generate gauge boson masses in a quantum field theory. However, strong evidence suggests that at least a pure φ⁴ scalar field theory is trivial or noninteracting. Should this triviality persist in more complicated systems such as the standard model of the weak interaction, the motivation for looking for Higgs particles would be seriously undermined. Alternatively, the presence of gauge and fermion fields can rescue a pure scalar theory from triviality. Phenomenological constraints (such as a bounded or even predictable Higgs mass) may then be implied. In this report the evidence for triviality in various field theories is reviewed, and the implications for high energy physics are discussed.     

The Elementary Particles of Quantum Fields

The elementary particles of relativistic quantum field theory are not simple field quanta, as has long been assumed. Rather, they supplement quantum fields, on which they depend on but to which they are not reducible, as shown here with particles defined instead as a unified collection of properties that appear in both physical symmetry group representations and field propagators. This notion of particle provides consistency between the practice of particle physics and its basis in quantum field theory.     

General neutrino mass spectrum and mixing properties in seesaw mechanisms

Neutrinos stand out among the elementary particles because of their unusually small masses.Various seesaw mechanisms attempt to explain this fact.In this work,applying insights from matrix theory,we are in a position to treat variants of seesaw mechanisms in a general manner.Specifically,using Weyl's inequalities,we discuss and rigorously prove under which conditions the seesaw framework leads to a mass spectrum with exactly three light neutrinos.We find an estimate of the mass of heavy neutrinos to be the mass obtained by neglecting light neutrinos,shifted at most by the maximal strength of the coupling to the light neutrino sector.We provide analytical conditions allowing one to prescribe that precisely two out of five neutrinos are heavy.For higher-dimensional cases the inverse eigenvalue methods are used.In particular,for the CP-invariant scenarios we show that if the neutrino sector has a valid mass matrix after neglecting the light ones,i.e.if the respective mass submatrix is positive definite,then large masses are provided by matrices with large elements accumulated on the diagonal.Finally,the Davis-Kahan theorem is used to show how masses affect the rotation of light neutrino eigenvectors from the standard Euclidean basis.This general observation concerning neutrino mixing,together with results on the mass spectrum properties,opens directions for further neutrino physics studies using matrix analysis.     

On a new mathematical framework for fundamental theoretical physics

It is shown by means of general principles and specific examples that, contrary to a long-standing misconception, the modern mathematical physics of compressible fluid dynamics provides a generally consistent and efficient language for describing many seemingly fundamental physical phenomena. It is shown to be appropriate for describing electric and gravitational force fields, the quantized structure of charged elementary particles, the speed of light propagation, relativistic phenomena, the inertia of matter, the expansion of the universe, and the physical nature of time. New avenues and opportunities for fundamental theoretical research are thereby illuminated.     

Spinor fields in the theory of relativity and a generalization of Heisenberg's nonlinear spinor equation

Some years ago it was shown that the nonlinear term of Heisenberg's spinor equation can be derived by torsion of the Minkowski space (Cartan space). This result is applied in the investigations of this paper. As the Heisenberg equation does not show any connection with recent phenomenological theories in high energy physics, like the parton or quark model, the problems of the metric of space-time are discussed from the aspect of fundamental axioms of topology (Hausdorff space). It will be shown that Feynman's relativistic parton theory can be derived by means of a quantised de Sitter space, where the constant curvature can assume only discrete values. It is also possible to derive the Dirac equation from the same mathematical considerations. A nonlinear spinor equation will be formulated which contains the parton theory and the nonlinear term of the Heisenberg equation as different approaches in the theory of elementary particles.     

Isolated neutron stars and studies of their interiors

In these lectures presented at Baikal summer school on physics of elementary particles and astrophysics 2011, I present a wide view of neutron star astrophysics with special attention paid to young isolated compact objects and studies of the properties of their interiors using astronomical methods.     

Exotic relics from the big bang

New, exotic (very heavy and/or very weakly interacting) particles would have been produced in the hot, dense environment of the early Universe. If sufficiently long-lived, some exotic relics would have survived to influence the subsequent evolution of the Universe; some may be present today. The laboratory and astrophysical information which can constrain the properties of such new particles is outlined and guidelines are presented for testing models of elementary particle physics.