OBSERVABLE CONSEQUENCES OF THE STRONG COUPLING PHASE OF QED HYPOTHESIZED NEAR THE SURFACE OF LARGE-Z NUCLEI

1990 ◽  
Vol 05 (05) ◽  
pp. 309-314 ◽  
Author(s):  
M. INOUE ◽  
T. MUTA ◽  
J. SAITO ◽  
H.-L. YU
Keyword(s):  
Strong Coupling ◽  
Quantum Electrodynamics ◽  
External Disturbance ◽  
Surface Region ◽  
Heavy Ion ◽  
Coincidence Measurement ◽  
Heavy Nuclei ◽  
Coupling Phase ◽  
Electron Positron ◽  
Large Atomic Number

We discuss observable effects of the assumption that the strong coupling phase of quantum electrodynamics is realized in the surface region of heavy nuclei with large atomic number Z under a suitable external disturbance. We present some comments on anomalous peaks in electron-positron systems observed in heavy ion reactions and on effects expected in electron and positron scatterings off large-Z nuclei. We propose some experiments to test our assumption: (1) coincidence measurement of e+e− and γγ signals from the decays of large-Z nuclei, and (2) spectroscopy of large-Z muonic atoms.

GAUGE INVARIANT STUDY OF THE STRONG COUPLING PHASE OF MASSLESS QUANTUM ELECTRODYNAMICS

1990 ◽  
Vol 05 (09) ◽  
pp. 1789-1800 ◽  
Author(s):  
M. UKITA ◽  
M. KOMACHIYA ◽  
R. FUKUDA
Keyword(s):  
Strong Coupling ◽  
Quantum Electrodynamics ◽  
Chiral Symmetry Breaking ◽  
Renormalization Scheme ◽  
Gauge Parameter ◽  
Coupling Constant ◽  
Critical Coupling ◽  
Gauge Invariant ◽  
Coupling Phase ◽  
Massless Quantum

The strong coupling phase of massless Quantum Electrodynamics is studied in a gauge invariant way. The formalism is given in which the order parameter of the chiral symmetry breaking is calculated through the vacuum polarization diagrams. Applying this method, the critical coupling constant is shown to exist that is independent of the gauge parameter but is now dependent on the ratio of the two kinds of cutoff. Implication of this new parameter on the renormalization scheme in the strong coupling phase is discussed.

scholarly journals Positronia’ Clouds in Universe

Universe ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Igor M. Dremin
Keyword(s):  
Electromagnetic Fields ◽  
Cross Sections ◽  
Galactic Center ◽  
Heavy Ion ◽  
Strong Interactions ◽  
Relativistic Electrons ◽  
Heavy Nuclei ◽  
Nuclear Collisions ◽  
Electron Positron ◽  
Low Mass

The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia clouds. Unbound electron–positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favors abundant creation of the unbound electron–positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore, we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z4 (Z is the electric charge of a heavy ion) compared to protons with Z = 1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e+e−-pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.

PHOTON PAIRING AND THE STRONG COUPLING PHASE OF MASSIVE QUANTUM ELECTRODYNAMICS COOPER EQUATION

1990 ◽  
Vol 05 (06) ◽  
pp. 381-390 ◽  
Author(s):  
T. INAGAKI ◽  
M. KOMACHIYA ◽  
R. FUKUDA
Keyword(s):  
Fine Structure ◽  
External Field ◽  
Strong Coupling ◽  
Quantum Electrodynamics ◽  
Structure Constant ◽  
Critical Value ◽  
Low Energy ◽  
Fine Structure Constant ◽  
Coupling Phase ◽  
Effective Lagrangian

Through the Cooper equation of the photon pairing, the instability of the normal vacuum of the Quantum Electrodynamics with the massive electron is studied. Using the low energy effective Lagrangian, the normal vacuum is shown to be unstable against the condensation of the photon pairs above the critical value of the fine structure constant. These agree with the previous results obtained by the Bethe-Salpeter equation. The presence of the weak electric external field enhances the instability thus lowering the critical value. This can be a basis for the explanation of the anomalous GSI e+e− events.

scholarly journals Electron-Positron Vacuum Instability in Strong Electric Fields. Relativistic Semiclassical Approach

Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 104
Author(s):  
Dmitry N. Voskresensky
Keyword(s):  
Electric Fields ◽  
Quantum Electrodynamics ◽  
Finite Size ◽  
Heavy Ion ◽  
Semiclassical Approach ◽  
Ion Collisions ◽  
Electron Positron ◽  
Lower Continuum ◽  
Strong Electric Fields ◽  
Spinless Boson

The instability of electron-positron vacuum in strong electric fields is studied. First, falling to the Coulomb center is discussed at Z>137/2 for a spinless boson and at Z>137 for electron. Subsequently, focus is concentrated on description of deep electron levels and spontaneous positron production in the field of a finite-size nucleus with the charge Z>Zcr≃170. Next, these effects are studied in application to the low-energy heavy-ion collisions. Subsequently, we consider phenomenon of “electron condensation” on levels of upper continuum crossed the boundary of the lower continuum ϵ=−m in the field of a supercharged nucleus with Z≫Zcr. Finally, attention is focused on many-particle problems of polarization of the quantum electrodynamics (QED) vacuum and electron condensation at ultra-short distances from a source of charge. We argue for a principal difference of cases, when the size of the source is larger than the pole size rpole, at which the dielectric permittivity of the vacuum reaches zero and smaller rpole. Some arguments are presented in favor of the logical consistency of QED. All of the problems are considered within the same relativistic semiclassical approach.

CRITICAL LINE AND BETHE-SALPETER EQUATION IN STRONG-COUPLING QED WITH FOUR-FERMION INTERACTIONS

1989 ◽  
Vol 04 (07) ◽  
pp. 605-612 ◽  
Author(s):  
M. INOUE ◽  
T. MUTA ◽  
T. OCHIUMI
Keyword(s):  
Symmetry Breaking ◽  
Strong Coupling ◽  
Chiral Symmetry ◽  
Quantum Electrodynamics ◽  
Phase Structure ◽  
Bound States ◽  
Critical Line ◽  
Chiral Symmetry Breaking ◽  
Electron Positron ◽  
Symmetric Phase

On the basis of Bethe-Salpeter equations for electron-positron bound states in strong-coupling quantum electrodynamics with additional four-fermion interactions, the formula for the critical line dividing the chiral-symmetry-breaking phase from the symmetric phase is derived. The beta functions near the critical line are calculated explicitly and the phase structure is discussed based on these beta functions.

scholarly journals Monopole–antimonopole pair production by magnetic fields

2019 ◽  
Vol 377 (2161) ◽  
pp. 20190333
Author(s):  
Arttu Rajantie
Keyword(s):  
Magnetic Fields ◽  
Quantum Electrodynamics ◽  
Strong Electric Field ◽  
Hadron Collider ◽  
Heavy Ion ◽  
New Physics ◽  
Magnetic Monopoles ◽  
Quantum Tunnelling ◽  
Electron Positron ◽  
Ion Collision

Quantum electrodynamics predicts that in a strong electric field, electron–positron pairs are produced by the Schwinger process, which can be interpreted as quantum tunnelling through the Coulomb potential barrier. If magnetic monopoles exist, monopole–antimonopole pairs would be similarly produced in strong magnetic fields by the electromagnetic dual of this process. The production rate can be computed using semiclassical techniques without relying on perturbation theory, and therefore it can be done reliably in spite of the monopoles' strong coupling to the electromagnetic field. This article explains this phenomenon and discusses the bounds on monopole masses arising from the strongest magnetic fields in the universe, which are in neutron stars known as magnetars and in heavy ion collision experiments such as lead–lead collisions carried out in November 2018 in the large Hadron collider at CERN. It will also discuss open theoretical questions affecting the calculation. This article is part of a discussion meeting issue ‘Topological avatars of new physics’.

Exploring Baryon Rich Matter with Heavy-Ion Collisions

2019 ◽  
Vol 64 (7) ◽  
pp. 583 ◽  
Author(s):  
S. Harabasz
Keyword(s):  
Center Of Mass ◽  
Heavy Ion ◽  
State Density ◽  
Heavy Nuclei ◽  
First Order ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Deconfinement Phase Transition ◽  
Ground State Density

Collisions of heavy nuclei at (ultra-)relativistic energies provide a fascinating opportunity to re-create various forms of matter in the laboratory. For a short extent of time (10-22 s), matter under extreme conditions of temperature and density can exist. In dedicated experiments, one explores the microscopic structure of strongly interacting matter and its phase diagram. In heavy-ion reactions at SIS18 collision energies, matter is substantially compressed (2–3 times ground-state density), while moderate temperatures are reached (T < 70 MeV). The conditions closely resemble those that prevail, e.g., in neutron star mergers. Matter under such conditions is currently being studied at the High Acceptance DiElecton Spectrometer (HADES). Important topics of the research program are the mechanisms of strangeness production, the emissivity of matter, and the role of baryonic resonances herein. In this contribution, we will focus on the important experimental results obtained by HADES in Au+Au collisions at 2.4 GeV center-of-mass energy. We will also present perspectives for future experiments with HADES and CBM at SIS100, where higher beam energies and intensities will allow for the studies of the first-order deconfinement phase transition and its critical endpoint.

scholarly journals POSSIBILITY OF FORMING A LARGE DCC IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS

2000 ◽  
Vol 15 (15) ◽  
pp. 2269-2288
Author(s):  
SANATAN DIGAL ◽  
RAJARSHI RAY ◽  
SUPRATIM SENGUPTA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Heavy Ion ◽  
High Energy ◽  
Chiral Condensate ◽  
Relativistic Heavy Ion Collisions ◽  
Maximum Temperature ◽  
Chiral Field ◽  
Heavy Nuclei ◽  
True Vacuum

We demonstrate the possibility of forming a single, large domain of disoriented chiral condensate (DCC) in a heavy-ion collision. In our scenario, rapid initial heating of the parton system provides a driving force for the chiral field, moving it away from the true vacuum and forcing it to go to the opposite point on the vacuum manifold. This converts the entire hot region into a single DCC domain. Subsequent rolling down of the chiral field to its true vacuum will then lead to emission of a large number of (approximately) coherent pions. The requirement of suppression of thermal fluctuations to maintain the (approximate) coherence of such a large DCC domain, favors three-dimensional expansion of the plasma over the longitudinal expansion even at very early stages of evolution. This also constrains the maximum temperature of the system to lie within a window. We roughly estimate this window to be about 200–400 MeV. These results lead us to predict that extremely high energy collisions of very small nuclei (possibly hadrons) are better suited for observing signatures of a large DCC. Another possibility is to focus on peripheral collisions of heavy nuclei.

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