Elementary Particle Processes Research Articles

Quantum integration of elementary particle processes

We apply quantum integration to elementary particle-physics processes. In particular, we look at scattering processes such as e+e−→qq¯ and e+e−→qq¯′W. The corresponding probability distributions can be first appropriately loaded on a quantum computer using either quantum Generative Adversarial Networks or an exact method. The distributions are then integrated using the method of Quantum Amplitude Estimation which shows a quadratic speed-up with respect to classical techniques. In simulations of noiseless quantum computers, we obtain per-cent accurate results for one- and two-dimensional integration with up to six qubits. This work paves the way towards taking advantage of quantum algorithms for the integration of high-energy processes.

False Chirality, Absolute Enantioselection and CP Violation: Pierre Curie’s Legacy

The 1884 suggestion of Pierre Curie (1859–1906) that the type of dissymmetry shown by collinear electric and magnetic fields may induce an enantiomeric excess, in a chemical reaction that would otherwise produce a racemic mixture, is explored in the context of fundamental symmetry arguments. Curie’s arrangement exhibits false chirality (time-noninvariant enantiomorphism), and so it may not induce absolute enantioselection (ae) in a process that has reached thermodynamic equilibrium, since it does not lift the degeneracy of chiral enantiomers. However, it may do so in far-from-equilibrium processes via a breakdown in microscopic reversibility analogous to that observed in elementary particle processes under the influence of CP violation, the associated force possessing false chirality with respect to CP enantiomorphism. In contrast, an influence like circularly polarized light exhibiting true chirality (time-invariant enantiomorphism) lifts the degeneracy of enantiomers, and so may induce ae in all circumstances. Although to date, ae has not been observed under the influence of Curie’s arrangement of collinear electric and magnetic fields, it is argued that two different experiments have now demonstrated ae under a falsely chiral influence in systems far from equilibrium, namely in a spinning sample under a gravitational field, and in the separation of enantiomers at a ferromagnetic surface.

The three quark-current of delta-isobar

Strong decay D®Np is one of the best modes to search for particles with spin 3/2. D - isobar decay consist of 99% - hadronic decay and 1% - electromagnetic decay, i.e. in this process strong decay is dominating channel which makes it important for nuclear research. The relativistic three-quark current describe all parameters of particle in quantum field theory. The three-quark current of Delta-isobar is similar with all large group of particles with quantum numbers Jp=(3/2)+. Relevant interpolating three-quark current is given in great details. It is shown that, this current has a single form. If we have three-quark current, we can write the interaction Lagrangian of baryon interacting with their constituent quarks. The Lagrangian is the base of the Standard model. The generalization of the current to nonlocal case can be used to such nonlocal theory as covariant quark model. Covariant quark model has been applied to a large number of elementary particle processes.       G M T   Английский Испанский Итальянский Казахский Китайский Трад Китайский Упр Корейский Русский Турецкий Французский   Английский Испанский Итальянский Казахский Китайский Трад Китайский Упр Корейский Русский Турецкий Французский                 Звуковая функция ограничена 200 символами     Настройки : История : Обратная связь : Donate Закрыть

Strong form factor of delta (1232)

Our article is devoted to study of the D®Np decay. Strong decay D®Np is one of the best modes to search for particles with spin 3/2. Strong decay is dominating channel of decay, i.e. D - isobar decay consist of 99% - hadronic decay, 1% - electromagnetic decay, therefore the decay is important for nuclear research. We calculate relevant form factors in the framework of the covariant quark model with infrared confinement in the full kinematical momentum transfer region. The covariant quark model has been applied to a large number of elementary particle processes. This model can be viewed as an effective quantum field approach to hadronic interactions, which based on an interaction Lagrangian of hadrons interacting with their constituent quarks. The coupling strength is determined by the compositeness condition ZH = 0 where ZH is the renormalization constant of the hadron wave function. We compare the obtained results with available experimental data and the results from other theoretical approaches.

The same key to different doors—temperature puzzles

The notion of temperature in many body elementary particle processes is in a common use for decades. Thermal models have become simple and universal effective tools to describe particle production—not only in high energy heavy ion collisions but also in high energy elementary particle collisions. We perform a critical analysis of the temperature concepts in such processes. Although the temperature concept is a very useful tool, nevertheless it should be used with the care, taking into account that usually it is just model dependent fitted parameter.

True and false chirality and absolute enantioselection

The discrete symmetries of parity P, time reversal T, and charge conjugation C are used to characterize the properties of chiral systems. The concepts of true chirality (time-invariant enantiomorphism) and false chirality (time-noninvariant enantiomorphism) that emerge provide an extension of Lord Kelvin’s original definition of chirality to situations where motion is an essential ingredient thereby clarifying, inter alia, the nature of physical influences able to induce absolute enantioselection. Only a truly chiral influence lifts the degeneracy of chiral enantiomers and so may induce absolute enantioselection in all circumstances. Chiral enantiomers remain strictly degenerate under a falsely chiral influence, which may therefore not induce absolute enantioselection in a process that has reached thermodynamic equilibrium, but may do so in far-from-equilibrium processes via a breakdown in microscopic reversibility analogous to that observed in elementary particle processes under the influence of CP violation. Parity violation and CP violation are suggested to be manifestations of true and false cosmic chirality, respectively, and their possible roles in abiotic enantioselection discussed.

On the Planck scale and properties of matter

Invariant and long-lived physical properties and structures of matter are modeled by intrinsic rotations in three and four degrees of freedom. The rotations are quantized starting from the Planck scale by using a nonlinear 1/r potential and period doubling—a common property of nonlinear dynamical systems. The absolute values given by the scale-independent model fit closely with observations in a wide range of scales. A comparison is made between the values calculated from the model and the properties of the basic elementary particles, particle processes, planetary systems, and other physical phenomena. The model also shows that the perceived forces can be divided into two categories: (1) force is always attractive, like in gravitation and (2) force is attractive or repulsive, like in electrostatics.

Electrodynamic metaphors: communicating particle physics with Feynman diagrams

The aim of this project is to communicate the basic laws of particle physics with Feynman diagrams - visual tools which represent elementary particle processes. They were originally developed as a code to be used by physicists and are still used today for calculations and elaborations of theoretical nature. The technical and mathematical rules of Feynman diagrams are obviously the exclusive concern of physicists, but on a pictorial level they can help to popularize many concepts, ranging from matter and the antimatter; the creation, destruction and transformation of particles; the role of "virtual" particles in interactions; the conservation laws, symmetries, etc.

False chirality, CP violation and the breakdown of microscopic reversibility in chiral molecular and elementary particle processes

False chirality, CP violation and the breakdown of microscopic reversibility in chiral molecular and elementary particle processes

Antiprotons Cooled to 4 K and Weighed in a Penning Trap

Any Lorentz-invariant local field theory must obey the CPT theorem. That is to say, the theory must be invariant under the combined operations of charge conjugation, parity inversion and time reversal, even though we know that these symmetries, taken one at a time, can be violated in elementary-particle processes. It follows that particles and their antiparticles must have identical masses and equal magnetic moments (of opposite sign).

Why superstrings?

Abstract The standard gange field theory of strong and electroweak interactions is believed to explain all known elementary particle processes up to an energy of at least 1 TeV. It is likely that this model can be enlarged to account for even higher energies, perhaps approaching the Planck scale of 1019 GeV. However, field theory offers no explanation, even in principle, of the origin of the gauge group(s), of the representations which actually occur in nature, nor of the values of the twenty odd parameters which appear in the theory. In principle, superstrings can answer these questions, and also give a finite quantum theory of gravitation. This article tries to show how this is possible, and to describe the enormity of the task being undertaken.

Mutually interacting charge fields: a new approach to gauge theoretical formulations of elementary-particle processes

Physical events in spg~e-time always involve an observe an ~ object to be observed ~. This is true, especially in the classical domain, for charged particles. Specifically the very ac t of t ruing to classically observe an elementary charged particle (or its associated electromagnetic field) always involves other charged particles. Because of the empirical existence of an indivisible unit of electric charge in Nature, the paradigm of ~ elementary ~> charged particle and ~ elementary ~> electromagnetic field (as used in conventional Maxwell-Lorentz formulations of classical eleetrodynamics) is classically nonoperational in the microcosm. This is because one cannot reduce the value of the measuring charge continuously to zero, but merely to the l imit of one electron charge. Hence the very act of classically trying to observe an ~ elementary ~> charge will always involve other such ~ elementary ,~ charges in the detection apparatus. Since the paradigm of elementary charged particle is classically nonoperational (within the framework of purely microscopic electromagnetic interactions), one is tempted to t ry to elminate the concept from purely electromagnetic formulations of classical electron theory, but cannot consistently do so without changing the basic formulation from the conventional MaxwellLorentz theory. A simple way of accomplishing this, without el iminating the fields entirely (as in Wheeler-Feynman electrodynamics), is to rede]ine the basic interacting electrodynamic degrees o] ]reedom as being ~ charge-]ields , (i.e. each charge has its own set of Maxwell field equations, with their own associated set of ~ charge-Field ~> solutions, and postulate that physical reality is ~ wp o] mutual interactions between various ~ charge-]ielde ~ in spacetime. We call this formulation (Classical Elementary Measurement Electrodynan~ics ) (i). In order to understand the structure of the new formalism, a ~ direct-(charge-field)action ~ type of classical electrodynamie theory, it is best to view it from the context of its comparison to conventional Maxwell-Lorentz clectrodynamics, and other alternative ~ Direct-Action ,~ formulations.

Monte Carlo generation of two body resonant states

For Monte Carlo calculations of elementary particle processes, the transition rate integral can be written in terms of intermediate mass variables. Events generated in this way bear a weight factor consisting of the product of the squared transition amplitude and several two-body phase space factors. Importance sampling, using a Breit-Wigner density, can improve efficiency in the case that one or more mass variables of the transition density are well approximated by a Breit-Wigner resonance. With the further restriction that the resonance occurs close to threshold and decays to two final-state particles, we have improved the efficiency by sampling a probability density which is the product of a Breit-Wigner density times the associated two-body phase space factor.

Effect of a Constant Magnetic Field on the Neutron Beta Decay Rate and its Astrophysical Implications

RECENT advances in the production of large magnetic fields in the laboratory1,2 have generated interest in the effect of intense magnetic fields on various phenomena3,4. The largest field that can be produced in the laboratory1,2 at present is about 106 G, which is considerably lower than the quantum critical field value5 of Hc = m2c3/eV = 4.4 × 1013 G; but the “cosmic laboratory” may be a source of much stronger fields and it has been suggested6 that magnetic fields as large as 1014−1016 G may exist in neutron stars. Hoyle7 has cited the possibility of a large primordial magnetic field, and Brownell and Callaway8 speculate that neutron stars and the dense early universe may be ferromagnetic. One of us (R. F. O.) has examined9 various effects of a large magnetic field and has indicated an effect of magnetic fields which has been often ignored in astrophysical investigations, namely, that the rates of all elementary particle processes will be affected. Pursuing this idea, we examine here the effect of a magnetic field on the β decay rate of a neutron. This is a fundamental process in many astrophysical phenomena and in particular it is very important10 in a problem of current interest, that is, the production of He in the “big-bang” expansion of the universe11. In addition, our calculations should be applicable to other elementary particle processes. We present here only the main ideas ; the calculation details will be published elsewhere12.

Difraction Patterns for Inelastic Elementary Particle Processes

Difraction Patterns for Inelastic Elementary Particle Processes

The interactions of unstable particles

The interactions of unstable particles with nucleons are examined. Such interactions can occur in high-energy nuclear reactions and as final-state interactions of elementary particle processes. The interactions of two strange unstable particles, Y0** and K* are discussed as an example. It is found that particles of narrow width, such as the Y0** which are created inside the nucleus have a good chance of escaping from the nucleus before they decay and may thus be detected experimentally. This is not true for particles of large width. Of particular interest for final state interactions are the sharp resonance-like peaks which may occur in the cross-sections of some of the interactions of unstable particles. These peaks are not associated with resonances but are related to the anomalous thresholds encountered in the interactions of loosely bound particles.

On the role of gravitational fields in some elementary particle processes

With the aid of a suitable perturbation formalism, the effect of an external gravitational field on elementary particle processes is investigated. Electromagnetic bremsstrahlung by charged scalar particle waves is treated and the dependence of the result on the inserted data and their empirical limits is analised. Application of the results to gravitational bremsstrahlung by particles of vanishing rest-mass is made. On the basis of these results, gravitational radiation from elementary particle processes is shown to be negligible. Some quantum electrodynamic processes of higher order, with closed loop diagrams are treated in curved space and the removal of their infinities by renormalization is discussed. Part of the matrix element for the process of photon trisection into three photons, has been evaluated and an upper limit for the cross-section of this process has been obtained in first order approximation in the external gravitational field. The magnitude of certain contributions from higher order terms has been estimated, but complete conclusions have not yet been obtained. A number of other processes, involving particles with spin and their radiative corrections are treated or discussed. Among the cross-sections of these processes, in first order perturbation only that for the trisection of photons becomes significant at the empirical energy limit: these theoretical results at present deny experimental possibilities. The role of terms of higher order is not yet known. Experimental possibilities for obtaining improved knowledge of the empirical upper limit of the energy losses produced on photons are suggested. General empirical aspects of the theoretical results are discussed. The Appendix contains an auxiliary theorem on a relation between the second derivatives of the metric tensor and the Riemann-Christoffel tensor at points, where geodesic co-ordinates are introduced.