Search

Accounting for the effects of local parity nonconservation in a strongly interacting medium is implemented within the framework of the Monte Carlo model. Predictions are obtained for the distributions of the invariant masses of di-muons and di-electrons from the decays of light vector mesons in Pb–Pb collisions at the LHC energy, taking into account the resolution of the detecting systems. The influence of fluctuations of the axial chemical potential is estimated. [ABSTRACT FROM AUTHOR]

Hindering of inversion transitions and a violation of mirror symmetry of the right- and left-handed configurations of diazabizyclooctane (dabco, N2C6H12) enantiomers has been studied with lowtemperature adiabatic calorimetry. The dabco molecules were sandwiched in a high-porous layered structure of a metal organic framework (MOF) compound. We show from the data of low-temperature adiabatic calorimetry and ¹H NMR spin relaxation method that hindering of inversion transitions of dabco molecules cannot be associated with the influence of the intracrystalline self-consistent molecular field as a continuously monitoring environment within the quantum Zeno effect. In addition, lack of another manifestation of this effect associated with the collisional suppression of the inversion transitions in MOF samples impregnated by helium has been shown. These results lead to the conclusion that chiral polarization is related to the fundamental effect of parity nonconservation. [ABSTRACT FROM AUTHOR]

We employ triple-resonance vibrational overtone excitation to access quasibound states of water from several fully characterized bound states of the molecule. Comparison of the measured dissociation spectra allows a rigorous assignment of rotational quantum numbers J, nuclear spin and parity, and a tentative vibrational characterization of the observed resonances. Their asymmetrical shapes (Fano profiles) reflect interference of dipole moments for transitions to these resonances with that to the dissociative continuum. The assignments and Fano profile parameters of the resonances stand as a benchmark for the extension of accurate quantum-mechanical calculations to activated complexes of water. The narrow widths of some of these resonances indicate that water molecules may survive for as long as up to 60 ps in states above the dissociation threshold. We consider the possible implication of such long-lived states for the kinetics of water dissociation and the OH+H association reaction. [ABSTRACT FROM AUTHOR]

Parity violation (PV) effects for a series of chiral molecules of the type SeOXY (X,Y=H, F, Cl, Br, or I) are predicted from four-component relativistic Hartree–Fock and density functional theory. All optimized SeOXY structures are nonplanar with large inversion barriers ranging from 23 to 55 kcal/mol; thus, all SeOXY molecules remain enantiomeric stable on the laboratory time scale. The variation in PV between the different methods applied is small enough for each molecule to allow for an accurate prediction of these effects. At the respective equilibrium geometries the enantiomers exhibit parity violating energy shifts of up to 17 Hz. The Se–O stretching mode of all investigated SeOXY molecules lies in the experimentally favorable CO2 laser range of ∼1000 cm-1. We therefore investigated PV effects in vibrational transitions along a single normal mode using Dirac–Kohn–Sham theory. The PV energy differences in the fundamental Se–O stretching mode amount up to 110 mHz (largest for SeOClI) and are larger compared to the C–F stretching mode of CHFBrI previously investigated. Hence these SeOXY molecules are ideal candidates for the future experimental gas-phase detection of PV in vibrational spectra of chiral molecules. [ABSTRACT FROM AUTHOR]

The authors present the results of their calculation for the parity nonconserving 5p66s1/2→5p65d3/2 transition in Ba+ using the relativistic coupled-cluster theory in the singles, doubles, and partial triples approximation. The contributions from the leading intermediate states are explicitly considered. It is found that the largest contribution comes from the |5p66p1/2> state. Their results are in reasonable agreement with other calculations. [ABSTRACT FROM AUTHOR]

A systematic four-component relativistic study of the parity nonconservation (PNC) contribution to the (isotropic) NMR shielding constants of chiral molecules is presented for the P enantiomers of the series H2X2 (X=17O,33S,77Se,125Te,209Po). The PNC contributions are obtained within a linear response approach at the Hartree-Fock level. A careful design of the basis sets is necessary. The four-component relativistic results based on the Dirac-Coulomb Hamiltonian are compared with the nonrelativistic Lévy-Leblond results and those obtained by the spin-free modified Dirac Hamiltonian. The calculations confirm the nonrelativistic scaling law Z2.4 of the PNC contribution with respect to nuclear charge Z. However, the calculations also show that the overall scaling is significantly modified by relativistic effects. The scalar relativistic effect scales as Z4.7 for the selected set of molecules, whereas the spin-orbit effect, of opposite sign, scales better than Z6 and completely dominates the PNC contribution for the heaviest elements. This opens up the intriguing possibility of the experimental observation of PNC effects on NMR parameters of molecules containing heavy atoms. The presented formalism is expected to be valuable in assisting the search for suitable candidate molecules. [ABSTRACT FROM AUTHOR]

In this paper I will focus on the case of the discovery of parity nonconservation in weak interactions from the period spanning 1947–1957, and the lessons this episode provides for successful theory construction in HEP. I aim to (a) summarize the history into a coherent story for philosophers of science, and (b) use the history as a case study for the epistemological evolution of the understanding of weak interactions in HEP. Iconclude with some philosophical lessons regarding theory construction in physics. • Discovery of parity violation came despite the theoretical framework in 1950s physics. • Early theory construction thrived due to close contact between theory and experiment. • Modern fundamental physics should shift toward a focus on precision experiments. • Theoretical physics requires constant experimental checks in order to be confirmed. [ABSTRACT FROM AUTHOR]

The article focuses on issues and topics related to parity nonconservation relative to the study conducted by Albert Michelson and Edward Morley in 1887 at Cleveland, Ohio. The Michelson-Morley experiment led Albert Einstein to formulate his famous Theory of Relativity eighteen years later. The phrase "Parity is Not Conserved," has become the a favorite subject of discussion among the scientific community around the globe. In everyday language, this phrase roughly means that some laws of nature are not symmetrical.

We investigate the parity-violating pion–nucleon–nucleon coupling constant h π N N 1 , based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating πNN constant h π N N 1 . We obtain a value of about 10 − 7 at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20%. [ABSTRACT FROM AUTHOR]

This article introduced Prof. WU Jian-xiong's most prominent scientific achievements and her life story. No matter in middle school or university, the young Jian-xiong always is a most understanding student, she selected the nuclear physics as her major, and went on the road of experimental physics, and made the excellent contribution to the βdecay experiment research. The paper focuses on the parity nonconservation experiment with epoch-making significance made by Prof WU. At the end of this paper, Prof. WU herself reminiscence is expounded, and the praise and miss to her are narrated. [ABSTRACT FROM AUTHOR]

The observation in the title made earlier in association with the Pais-Uhlenbeck oscillator with equal frequencies is illustrated for an elementary matrix model. In the limit $N \to \infty $ ( N being the order of the exceptional point), an infinity of nontrivial states that do not change their norm during evolution appear. These states have real energies lying in a continuous interval. The norm of the 'precursors' of these states at large finite N is not conserved, but the characteristic time scale where this nonconservation shows up grows linearly with N. [ABSTRACT FROM AUTHOR]

Copyright of Technical Journal / Tehnički Glasnik is the property of Polytechnic of Varazdin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work builds on the Volterra series formalism presented in Dreisigmeyer and Young (J Phys A 36: 8297, ) to model nonconservative systems. Here we treat Lagrangians and actions as 'time dependent' Volterra series. We present a new family of kernels to be used in these Volterra series that allow us to derive a single retarded equation of motion using a variational principle. [ABSTRACT FROM AUTHOR]

New discoveries and theories are crucial for the development of science, but they are often initially resisted by the scientific community. This paper analyses resistance to scientific discoveries that supplement previous research results or conclusions with new phenomena, such as long chains in macromolecules, Alfvén waves, parity nonconservation in weak interactions and quasicrystals. Construal-level theory is used to explain that the probability of new discoveries may be underestimated because of psychological distance. Thus, the insufficiently examined scope of an accepted theory may lead to overstating the suitable scope and underestimating the probability of its undiscovered counter-examples. Therefore, psychological activity can result in people instinctively resisting new discoveries. Direct evidence can help people judge the validity of a hypothesis with rational thinking. The effects of authorities and textbooks on the resistance to discoveries are also discussed. From the results of our analysis, suggestions are provided to reduce resistance to real discoveries, which will benefit the development of science. [ABSTRACT FROM AUTHOR]

Recent results concerning negative-parity states in 16C are analyzed in terms of the shell model and a simple weak-coupling model. We suggest the state at 6.28 MeV is 2-, and the state near 6.1 MeV is not 3-, but probably 1- (0-). [ABSTRACT FROM AUTHOR]

In the framework of Friedmann-Lemaitre-Robertson-Walker cosmology modified by entropic issues, the sign change of the inhomogeneous term associated with the nonconservation energy equation for cosmic fluid is discussed; specifically, this is a bare/effective study of the equation of state for this fluid through a bare ( ω)/effective ( ω) description. In the bare case, where there is a nonconserved equation of state, the change in the sign of the inhomogeneous term at different times of the cosmic evolution is described. By redefining the adiabatic ω-parameter, the usual scheme for cosmic evolution can be recovered. In the effective case, if evolution is driven by dust or the cosmological constant, the universe evolves towards thermal equilibrium. However, by incorporating a quantum correction, only the cosmological constant can lead to thermal equilibrium. This correction avoids the future singularity that is present when it is not incorporated. [ABSTRACT FROM AUTHOR]

Abstract: The critical forces of massless conservative systems can be calculated using equilibrium conditions on the deformed systems. However, if non-trivial equilibrium conditions are absent (e.g., Beck's and Ziegler's column), then the equilibrium method is not applicable. Therefore, these systems were supplied with mass and calculations were performed dynamically. This manuscript demonstrates that the static stability of massless non-conservative systems can be calculated using the energetic stability criterion. [Copyright &y& Elsevier]