Effects Of Symmetry Violation Research Articles

On the Lorentz Symmetry Violation Effects on a Particle Subject to a Trigonometric Potential and a Periodic Potential

On the Lorentz Symmetry Violation Effects on a Particle Subject to a Trigonometric Potential and a Periodic Potential

Lorentz Symmetry Violation Effects Caused by the Coupling between the Field fμγ5 and the Derivative of the Fermionic Field on One-Dimensional Potentials

In search of physics beyond the standard model, new phenomena can be relevant in low energies. In view of the Standard Model Extension is an effective field theory, in this study we explore the fermionic sector by showing that the properties of nonrelativistic quantum systems can be modified. We study one-dimensional nonrelativistic quantum systems under Lorentz symmetry violation effects caused by the coupling between the fixed vector field fμγ5 and the derivative of the fermionic field. We deal with the quantum bouncer, the attractive inverse-square potential, a modified attractive inverse-square potential, and a scalar exponential potential inside this scenario of the Lorentz symmetry violation. Then, we show that the spectra of energy are influenced by the Lorentz symmetry violation effects.

Nonrelativistic quantum effects of the Lorentz symmetry violation on the Morse potential

We search for Lorentz symmetry violation effects at low-energy regime by exploring the Dirac equation in (1 + 1)-dimensions and the possibility of dealing with quantum systems with spherical symmetry. We bring a discussion about the influence of the Lorentz symmetry violation effects on the spectrum of molecular vibrations caused by the coupling between a fixed vector field and the derivative of the fermionic field. Further, we discuss the influence of this Lorentz symmetry violation background on the revival time.

Electronic spectroscopy and ionization potentials for YbOH and YbOCH3

The polyatomic molecules YbOH and ${\mathrm{YbOCH}}_{3}$ have been recognized as being of potential value for spectroscopic experiments that explore charge-parity and time-reversal symmetry violation effects. These measurements require very high precision, which, in turn, will necessitate that the molecules be manipulated at ultracold temperatures. Both YbOH and ${\mathrm{YbOCH}}_{3}$ have electronic transitions that appear suitable for laser cooling ($\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A}{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Pi}}}_{1/2}\text{\ensuremath{-}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ and $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A\phantom{\rule{4pt}{0ex}}}{\phantom{\rule{0.16em}{0ex}}}^{2}{E}_{1/2}\text{\ensuremath{-}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}{\phantom{\rule{0.16em}{0ex}}}^{2}{A}_{1}$, respectively) but the currently available spectroscopic data are not sufficient to determine the extent to which population leaks may compromise the optical cooling processes. A further complication is that the quantum states of interest for these measurements will need to be selectively populated. The $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A}\text{--}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}$ band systems of both YbOH and ${\mathrm{YbOCH}}_{3}$ show evidence of vibronic perturbations, such that there are unassigned vibronic features at energies that are just above the origin bands. In the present study we have recorded spectra for the $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A}$ ${}^{2}{\mathrm{\ensuremath{\Pi}}}_{1/2}\text{\ensuremath{-}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ transition of jet-cooled YbOD to facilitate the vibronic assignments. In addition, spectra for the $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{B}{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}\text{\ensuremath{-}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ transition of YbOH were recorded, establishing the origin band at 20 473.8 $\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$. Previously, the reaction of Yb with ${\mathrm{CH}}_{3}\mathrm{OH}$ has been used to generate gas-phase ${\mathrm{YbOCH}}_{3}$. As this reaction also yields YbOH, there have been complications in spectroscopic studies of ${\mathrm{YbOCH}}_{3}$ due to overlap of the $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A}\text{--}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}$ band systems. To identify specific regions of overlap, resonantly enhanced two-photon ionization spectra were recorded using mass-resolved detection of the $\mathrm{YbO}{\mathrm{H}}^{+}$ and ${\mathrm{YbOCH}}_{3}^{+}$ ions. These data confirmed the overlap of vibronic bands near 17 640 and 17 680 $\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$. Two-photon ionization spectroscopy also provided accurate ionization energies (IE), $\mathrm{IE}(\mathrm{YbOH})=45\phantom{\rule{0.16em}{0ex}}788(10)$ and $\mathrm{IE}({\mathrm{YbOCH}}_{3})=45\phantom{\rule{4pt}{0ex}}283(10)\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$. The IE for YbOH is relevant to problems encountered in previous attempts to determine the bond-dissociation energy of $\mathrm{YbO}{\mathrm{H}}^{+}$.

Hulthén potential under the Lorentz symmetry violation effects due to the coupling between the vector field f μ γ 5and the derivative of the fermionic field

We search for Lorentz symmetry violation effects caused by the coupling between a fixed vector field and the derivative of the fermionic field in the nonrelativistic regime. By working with dimensions, we study nonrelativistic effects of the Lorentz symmetry violation on the energy eigenvalues of the Hulthén potential and the deformed Hulthén potential.

QCD calculations of B \u2192 \u03c0, K form factors with higher-twist corrections

We update QCD calculations of B → π, K form factors at large hadronic recoil by including the subleading-power corrections from the higher-twist B-meson light-cone distribution amplitudes (LCDAs) up to the twist-six accuracy and the strange-quark mass effects at leading-power in Λ/mb from the twist-two B-meson LCDA ϕB+(ω, μ). The higher-twist corrections from both the two-particle and three-particle B-meson LCDAs are computed from the light-cone QCD sum rules (LCSR) at tree level. In particular, we construct the local duality model for the twist-five and -six B-meson LCDAs, in agreement with the corresponding asymptotic behaviours at small quark and gluon momenta, employing the method of QCD sum rules in heavy quark effective theory at leading order in αs. The strange quark mass effects in semileptonic B → K form factors yield the leading-power contribution in the heavy quark expansion, consistent with the power-counting analysis in soft-collinear effective theory, and they are also computed from the LCSR approach due to the appearance of the rapidity singularities. We demonstrate explicitly that the SU(3)-flavour symmetry breaking effects between B → π and B → K form factors, free of the power suppression in Λ/mb, are suppressed by a factor of {alpha}_sleft(sqrt{m_bLambda}right) in perturbative expansion, and they also respect the large-recoil symmetry relations of the heavy-to-light form factors at least at one-loop accuracy. An exploratory analysis of the obtained sum rules for B → π, K form factors with two distinct models for the B-meson LCDAs indicates that the dominant higher-twist corrections are from the Wandzura-Wilczek part of the two-particle LCDA of twist five gB−(ω, μ) instead of the three-particle B-meson LCDAs. The resulting SU(3)-flavour symmetry violation effects of B → π, K form factors turn out to be insensitive to the non-perturbative models of B-meson LCDAs. We further explore the phenomenological aspects of the semileptonic B → πℓν decays and the rare exclusive processes B → Kνν, including the determination of the CKM matrix element |Vub|, the normalized differential q2 distributions and precision observables defined by the ratios of branching fractions for the above-mentioned two channels in the same intervals of q2.

A study of 3-form gauge theories in the Lorentz violating background

We study the Lorentz symmetry breaking of the 3-form gauge theory down to its sub-group. A 3-form gauge theory is studied in such a Lorentz violating background and these symmetry violation effects will affect the aspects of such a gauge theory. Also, we study the gaugeon formalism and FFBRST of 3-form theory in such a background. It is seen that the generating functional gets modified. With this, we obtain a connection between covariant and noncovariant gauges of such a gauge theory. Furthermore, we study the Batalin–Vilkovisky (BV) formulation of such a gauge theory in such a Lorentz violating background.

Geometric relativistic phase from Lorentz symmetry breaking effects in the cosmic string spacetime

In this paper, we have investigated the arising of geometric quantum phases in a relativistic quantum dynamics of a Dirac neutral particle from the spontaneous Lorentz symmetry violation effects in the cosmic string spacetime. We started by the Dirac equation in an effective metric, and we have observed a relativistic geometric phase which stems from the topology of the cosmic string spacetime and an intrinsic Lorentz symmetry breaking effects. It is shown that both Lorentz symmetry breaking effects and the topology of the defect yields a phase shift in the wave function of the nonrelativistic spin-[Formula: see text] particle.

Light-cone distribution amplitudes of the baryon octet

We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using $N_f=2+1$ flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.

Relativistic geometric quantum phases from the Lorentz symmetry violation effects in the CPT-even gauge sector of Standard Model Extension

We discuss the appearance of geometric quantum phases for a Dirac neutral particle in the context of relativistic quantum mechanics based on possible scenarios of the Lorentz symmetry violation tensor background in the CPT-even gauge sector of Standard Model Extension. We assume that the Lorentz symmetry breaking is determined by a tensor background given by [Formula: see text], then, relativistic analogues of the Anandan quantum phase [J. Anandan, Phys. Lett. A 138, 347 (1989)] are obtained based on the parity-even and parity-odd sectors of the tensor [Formula: see text].

On the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects on the harmonic oscillator

In this work, we obtain bound states for a nonrelativistic spin-half neutral particle under the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects. We present a new possible scenario of studying the Lorentz symmetry breaking effects on a nonrelativistic quantum system defined by a fixed space-like vector field parallel to the radial direction interacting with a uniform magnetic field along the z-axis. Furthermore, we also discuss the influence of a Coulomb-like potential induced by Lorentz symmetry violation effects on the two-dimensional harmonic oscillator.

Planck-scale modifications to electrodynamics characterized by a spacelike symmetry-breaking vector

In the study of Planck-scale (``quantum-gravity-induced'') violations of Lorentz symmetry, an important role was played by the deformed-electrodynamics model introduced by Myers and Pospelov. Its reliance on conventional effective quantum field theory, and its description of symmetry-violation effects simply in terms of a four-vector with a nonzero component only in the time direction, rendered it an ideal target for experimentalists and a natural concept-testing ground for many theorists. At this point however the experimental limits on the single Myers-Pospelov parameter, after improving steadily over these past few years, are ``super-Planckian''; i.e. they take the model out of actual interest from a conventional quantum-gravity perspective. In light of this we here argue that it may be appropriate to move on to the next level of complexity, still with vectorial symmetry violation but adopting a generic four-vector. We also offer a preliminary characterization of the phenomenology of this more general framework, sufficient to expose a rather significant increase in complexity with respect to the original Myers-Pospelov setup. Most of these novel features are linked to the presence of spatial anisotropy, which is particularly pronounced when the symmetry-breaking vector is spacelike, and they are such that they reduce the bound-setting power of certain types of observations in astrophysics.

Charge symmetry violation effects in pion scattering off the deuteron

We discuss the theoretical and experimental situations for charge symmetry violation (CSV) effects in the elastic scattering of ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ on deuterium (D) and ${}^{3}\mathrm{He}{/}^{3}\mathrm{H}.$ Accurate comparison of data for both types of targets provides evidence for the presence of CSV effects. While there are indications of a CSV effect in deuterium, it is much more pronounced in the case of ${}^{3}\mathrm{He}{/}^{3}\mathrm{H}.$ We provide a description of the CSV effect on the deuteron in terms of single- and double-scattering amplitudes. The $\ensuremath{\Delta}$-mass splitting is taken into account. Theoretical predictions are compared with existing experimental data for $\ensuremath{\pi}\ensuremath{-}d$ scattering; a future article will speak to the $\ensuremath{\pi}$-three nucleon case.

Status of the CP LEAR experiment and first results

The aim of the CP LEAR experiment is to study symmetry-violation effects, making use of tagged K 0's and K 0's . The detector, although missing some electronic components, has been operational for a few weeks at the end of 1989 at the CERN Low-Energy Antiproton Ring (LEAR). At the moment, the analysis of the data is in progress. This paper gives a description of the experimental method and of the detector; the sensitivities of some measurements and some preliminary results are also discussed.

Three- and four-nucleon systems (experiment)

A review of current problems in the three- and four-nucleon systems is presented. Recent experimental results are summarized. The state of the art in solving Faddeev equations is illustrated. The sensitivities of first order observables to different N-N interaction and also the merit of polarization transfer experiments, which has been recently carried out, are discussed. The importance of a proper treatment of the Coulomb force in three- and four nucleon calculation is stressed. It is demonstrated, that the inclusion of the Coulomb force is necessary when experimental results of mirror nuclei or mirror reactions are used to investigate possible charge symmetry violation effects. New results of the determination of the asymptotic D- to S-state normalization of the deuteron and triton wave function are reported.