Large Relative Phase Research Articles

Cross section of the process e+e−→ΛΛ¯ in the vicinity of charmonium ψ(3770) including three-gluon and D -meson loop contributions

The total cross section of the process $e^+e^- \to \Lambda\bar{\Lambda}$ is calculated within the energy range close to the mass of $\psi(3770)$ charmonium state. Two different contributions were considered: the $D$-meson loop and the three gluon charmonium annihilation one. Both of them contribute noticeably and in sum fairly reproduce the data. Large relative phase for these contributions are generated with respect to the pure electromagnetic mechanism. As a by product the fit for the electromagnetic form factor of $\Lambda$-hyperon is obtained for the large momentum transferred region.

Weather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines

Abstract Using a novel wide-slit, multiobject approach with the GMOS spectrograph on the 8 m Gemini South telescope, we have obtained precise time-series spectrophotometry of the binary brown dwarf Luhman 16 at optical wavelengths over two full nights. The B component of this binary system is known to be variable in the red optical and near-infrared with a period of 5 hr and an amplitude of 5%–20%. Our observations probe its spectrally resolved variability in the 6000–10000 Å range. At wavelengths affected by the extremely strong, broadened spectral lines of the neutral alkali metals (the potassium doublet centered near 7682 Å and the sodium doublet at 5893 Å), we see photometric variations that differ strikingly from those of the 8000–10000 Å “red continuum” that dominates our detected flux. On UT 2014 February 24, these variations are anticorrelated with the red continuum, while on February 25 they have a large relative phase shift. The extent to which the wavelength-dependent photometric behavior diverges from that of the red continuum appears to correlate with the strength of the alkali absorption. We consider but ultimately reject models in which our observations are explained by lightning or auroral activity. A more likely cause is cloud-correlated, altitude-dependent variations in the gas-phase abundances of sodium and potassium, which are in chemical equilibrium with their chlorides in brown dwarf atmospheres. Clouds could influence these chemical equilibria by changing the atmospheric temperature profile and/or through cloud particles acting as chemical catalysts.

Hyperon and antihyperon physics

Structure, interactions and decays of hyperons can be studied at an electron-positron collider in annihilations to a hyperon-antihyperon pair. This method already has huge impact on hyperon physics since it was used in a first modern measurement of decay asymmetry in the weak decay and the result calls for reinterpretation of all polarization results for the Λ hyperon. In the experiment by the BESIII Collaboration nearly half million events were used. The pair production process involves two (complex) hadronic form factors. The observed large relative phase ΔΦ between the form factors, (42.4±0.6±0.5)°, makes it possible to use both transverse polarization and the spin correlations of the pair to simultaneously measure decay parameters for Λ and hyperons. Of particular importance is the result for the decay asymmetry parameter α− in the most probable Λ decay used to determine Λ polarization. The new α− value from BESIII, 0.750±0.009±0.004, is 17(3)% larger than the world average of 0.642 ± 0.013 adopted by all experiments between 1978 and 2019 to determine Λ polarization from the measured asymmetry in the decay proton distribution. A comparison of the concurrently measured at BESIII α− and α+, the parameter for the charge conjugated process , results in a direct CP symmetry test for the hyperon.The reaction was studied at BESIII also outside the J/ψ resonance using 66.9 pb−1 collected at GeV. The result is the first complete determination of the time-like elastic form factors GM and GE for any baryon including the relative phase ΔΦ = arg(GE/GM ) of (37 ± 12 ± 6)°. The absolute normalization of the form factors is set by the determined Born cross section of σ Born= 119.0 ± 5.3 ± 5.1 pb. In a separate run at GeV, 1.0 MeV above threshold for , a surprisingly large cross section for of 305 ± pb was measured.

AnomalousB-meson mixing and baryogenesis

There exist experimental hints from the B sector for CP violation beyond the Standard Model (SM) CKM paradigm. An anomalous dimuon asymmetry was reported by the D0 collaboration, while tension exists between $B \to \tau \nu$ and $S_{\psi K}$. These measurements, disfavoring the SM at the ~3$\sigma$ level, can be explained by new physics in both $B_d$-$\bar{B}_d$ and $B_s$- $\bar{B}_s$ mixing, arising from (1) new bosonic degrees of freedom at or near the electroweak scale, and (2) new, large CP-violating phases. These two new physics ingredients are precisely what is required for electroweak baryogenesis to work in an extension of the SM. We show that a simple two Higgs doublet model with top-charm flavor violation can explain the B anomalies and the baryon asymmetry of the Universe. Moreover, the presence of a large relative phase in the top-charm Yukawa coupling, favored by $B_{d,s}$-$\bar{B}_{d,s}$ mixing, weakens constraints from $\epsilon_K$ and $b \to s \gamma$, allowing for a light charged Higgs mass of O(100 GeV).

Theoretical exploration of laser-parameter effects on the generation of an isolated attosecond pulse from two-color high-order harmonic generation

In the present work, laser-parameter effects on the isolated attosecond pulse generation from two-color high-order harmonic generation (HHG) process are theoretically investigated by use of a wave-packet dynamics method. A 6-fs, 800-nm, $6\ifmmode\times\else\texttimes\fi{}{10}^{14}{\mathrm{W}/\mathrm{cm}}^{2}$, linearly polarized laser pulse serves as the fundamental driving pulse and parallel linearly polarized control pulses at 400 nm (second harmonic) and 1600 nm (half harmonic) are superimposed to create a two-color field. Of the two techniques, we demonstrate that using a half-harmonic control pulse with a large relative strength and zero phase shift relative to the fundamental pulse is a more promising way to generate the shortest attosecond pulses. As a consequence, an isolated 12-as pulse is obtained by Fourier transforming an ultrabroad xuv continuum of 300 eV in the HHG spectrum under half-harmonic control scheme when the relative strength $\sqrt{R}=0.6$ and relative phase $=0$.

Ba0.60Sr0.40TiO3 THIN FILMS FOR MICROWAVE PHASE SHIFTER DEVICES: THE INFLUENCE OF CRYSTALLIZATION TEMPERATURE ON THE ELECTRIC FIELD DEPENDENT PHASE SHIFT RESPONSE

ABSTRACT We present the correlation between film fabrication conditions (crystallization temperatures), microstructure, and dielectric phase shift of Ba1−xSrxTiO3 (BST) thin films synthesized by metal organic solution deposition (MOSD) on sapphire substrates. The structure, microstructure, surface morphology, and composition of the films were assessed by glancing angle X-ray diffraction (GAXRD), atomic force microscopy (AFM), and Rutherford backscattering spectroscopy (RBS). The dielectric phase shift measurements were carried out using coplanar waveguide (CPW) test circuits over a frequency range of 2–18 GHz. Our results indicate that BST processed at 950°C achieved large relative phase shift response with low attenuation of the microwave signal.

The SU(3) symmetry breaking in J/ψ decays

We use SU(3) flavor symmetry to analyze the vector pseudoscalar and baryon–anti-baryon decays of J/ψ; both the SU(3) invariant and violating contribution are considered. Particular attention is paid to the interference of the electromagnetic and strong amplitudes; the current data favor a large relative phase of nearly 90° between the three-gluon and the one-photon decay amplitudes.

Strong and electromagneticJ/ψandψ(2S)decays into pion and kaon pairs

A combined analysis of the electromagnetic pion and kaon form factors in the neighborhood of J/{psi} and {psi}(2S) and of the strong decay amplitude of these resonances into kaons is presented. In the presence of a large relative phase between strong and electromagnetic resonance amplitudes the branching ratio, as measured in electron-positron annihilation, receives an additional contribution from the interference between resonance and continuum amplitude neglected in earlier papers. We note that the large relative phase between strong and electromagnetic amplitudes observed in earlier phenomenological analyses relies critically on the specific assumptions on SU(3) symmetry and breaking. Without these assumptions this phase remains effectively undetermined. Also, the modulus of their ratio depends critically on the details of the theory input.

A LOW VOLTAGE TUNABLE ANALOG PHASE SHIFTER UTILIZING FERROELECTRIC VARACTORS

ABSTRACT A distributed transmission line phase shifter was implemented by periodically loading a coplanar transmission line using ferroelectric varactors in a shunt configuration. A single dc bias applied to the phase shifter circuit provides a large relative phase shift. A relative phase shift of ∼ 305 degrees was obtained at 20 GHz for a dc bias of only 5 V.

Fresnel phase matching: Exploring the frontiers between ray and guided wave quadratic nonlinear optics

Fresnel phase matching is a convenient and universal way to phase match nonlinear three-wave mixing by total internal reflection in isotropic materials like common semiconductors. This technique makes use of the large relative phase lag between the interacting waves at total internal reflection, and was suggested by the nonlinear optics pioneers in the 70's; it has been worked out by several teams since then but, quite unexpectedly, has never succeeded in producing enough parametric gain to achieve optical parametric oscillation. We show that this failure stems mostly from a basic law of nonlinear reflection, which leads to a spatial walk-off between the pump and the generated parametric waves, resulting in unexpected destructive interference patterns between the waves while bouncing back and forth between the interfaces. Ray tracing or plane wave analysis gives an incomplete representation of the phenomenon while highly multimodal nonlinear guided wave theory reconciles the different views. Very good agreement between the presented theory and experiments is demonstrated in gallium arsenide samples.

B→ππ decays

The branching ratios and CP asymmetries of $B\to \pi\pi$ decays measured in B factory experiments indicate a large ratio of color-suppressed ($C$) to color-allowed ($T$) tree contributions and a large relative phase between the tree and penguin amplitude. In this talk, I would like to report on a recent analysis to see whether the large $C/T$ ratio can be explained within the QCD based model with i) a large contribution from the annihilation terms or with ii) large final-state-interaction phase between two different isospin amplitudes. We show that the current experimental data do not exclude either possibility but we may be able to distinguish these two effects in future measurements of direct CP asymmetry in $B\to \pi^{0}\pi^{0}$ decay.

Charmless decaysB→ππ,πKandKKin broken SU(3) symmetry

Charmless B decay modes $B \to \pi \pi, \pi K$ and $KK$ aresystematically investigated with and without flavor SU(3) symmetry. Independent analyses on $\pi \pi$ and $\pi K$ modes both favor a large ratio between color-suppressed tree ($C$) and tree ($T)$ diagram, which suggests that they are more likely to originate from long distance effects. The sizes of QCD penguin diagrams extracted individually from $\pi\pi$, $\pi K$ and $KK$ modes are found to follow a pattern of SU(3) breaking in agreement with the naive factorization estimates. Global fits to these modes are done under various scenarios of SU(3)relations. The results show good determinations of weak phase $\gamma$ in consistency with the Standard Model (SM), but a large electro-weak penguin $(P_{\tmop{EW}})$ relative to $T + C$ with a large relative strong phase are favored, which requires an big enhancement of color suppressed electro-weak penguin ($P_{\tmop{EW}}^C$) compatible in size but destructively interfering with $P_{\tmop{EW}}$ within the SM, or implies new physics. Possibility of sizable contributions from nonfactorizable diagrams such as $W$-exchange ($E$), annihilation($A$) and penguin-annihilation diagrams($P_A$) are investigated. The implications to the branching ratios and CP violations in $K K$modes are discussed.

Development of energy and time parameters in the walking of healthy human infants

Sixteen infants were analyzed longitudinally from the onset of independent walking to 3 years of age using time parameters, speed and energy recovery. Considerable variation and irregularities were observed in many parameters of infant walking, especially until 13 months of age when infants had difficulty in walking steadily step by step. Infant walking until 3 years of age was characterized by a small braking duration, caused mainly by the forward inclination of the trunk, a large relative stance phase duration, which maintained static balance, short stride length, due to the small range of the lower limb joint angle, and a small recovery of external energy. These characteristics were also predominantly evident until 13 months of age. The small recovery characteristic of infants was caused by flexed lower limb joints, pronounced irregularities in energy output, and in younger infants, slow speed. The maximum recovery up until 2 years of age, though smaller than in adults, appeared at about 0.45 dimensionless speed, which is about the same speed that adults in particular naturally and at which their maximum recovery appeared. The forward inclination of the trunk and the lower limb joint angle, influenced the development of many characteristics of bipedal walking.

Fresnel phase matching for three-wave mixing in isotropic semiconductors

We deal with phase matching of three-wave mixing by total internal reflection in isotropic semiconductors. This technique makes use of the large relative phase lag between the three interacting waves at total internal reflection, as described by Augustin Fresnel. This is why we denote this technique as Fresnel phase matching. The theory of Fresnel phase matching is developed with a propagation matrix method: It allows us to describe the conditions (sample thickness, polarization, tuning angles, etc.) for phase matching, the influence of surface roughness, and the walk-off effects due to Goos–Hänchen shifts. Moreover, we show that nonresonant phase matching strongly alleviates the phase-matching tolerance while keeping good conversion yields. The potential of this technique is demonstrated by largely tunable mid-infrared generation (between 7 and 13 μm with a single sample) by use of difference-frequency mixing of two near-infrared sources. Excellent agreement between the presented theory and experiments is demonstrated both in GaAs and ZnSe samples.

Nonfactorizable contributions toB→D(*)Mdecays

While the naive factorization assumption works well for many two-body nonleptonic B meson decay modes, the recent measurement of $\overline{B}\ensuremath{\rightarrow}{D}^{(*)0}{M}^{0}$ with $M=\ensuremath{\pi},$ $\ensuremath{\rho},$ and $\ensuremath{\omega}$ shows a large deviation from this assumption. We analyze the $\stackrel{\ensuremath{\rightarrow}}{B}{D}^{(*)}M$ decays in the perturbative QCD approach based on the ${k}_{T}$ factorization theorem, in which both factorizable and nonfactorizable contributions can be calculated in the same framework. Our predictions for the Bauer-Stech-Wirbel parameters, $|{a}_{2}{/a}_{1}|=0.43\ifmmode\pm\else\textpm\fi{}0.04$ and $\mathrm{Arg}{(a}_{2}{/a}_{1})\ensuremath{\sim}\ensuremath{-}42\ifmmode^\circ\else\textdegree\fi{}$ and $|{a}_{2}{/a}_{1}|=0.47\ifmmode\pm\else\textpm\fi{}0.05$ and $\mathrm{Arg}{(a}_{2}{/a}_{1})\ensuremath{\sim}\ensuremath{-}41\ifmmode^\circ\else\textdegree\fi{},$ are consistent with the observed $\stackrel{\ensuremath{\rightarrow}}{B}D\ensuremath{\pi}$ and $\stackrel{\ensuremath{\rightarrow}}{B}{D}^{*}\ensuremath{\pi}$ branching ratios, respectively. It is found that the large magnitude $|{a}_{2}|$ and the large relative phase between ${a}_{2}$ and ${a}_{1}$ come from color-suppressed nonfactorizable amplitudes. Our predictions for the ${B}^{0}\ensuremath{\rightarrow}{D}^{*0}{\ensuremath{\rho}}^{0}{,D}^{*0}\ensuremath{\omega}$ branching ratios can be confronted with future experimental data.

Analysis of supersymmetric effects onB→φKdecays in the PQCD approach

We study the effects of the MSSM contribution on $\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\varphi}K$ decays using the perturbative QCD approach. In this approach, strong phases can be calculated, so that we can predict the values of CP asymmetries with the MSSM contribution. We predict a large relative strong phase between the penguin amplitude and the chromomagnetic penguin amplitude. If there is a new CP violating phase in the chromomagnetic penguin amplitude, then the CP asymmetries may change significantly from the SM prediction. We parametrize the new physics contributions that appear in the Wilson coefficients. We maximize the new physics parameters up to the point where it is limited by experimental constraints. In the case of the LR insertion, we find that the direct CP asymmetries can reach about 85% and the indirect CP asymmetry can reach about $\ensuremath{-}30%.$

Relative phase between the J/ψ → ρη and ωη amplitudes

It is shown that the study of the ω-ρ0 interference pattern in J/ψ → (ρ0+ω)η → π+ π− η decay provides evidence for a large (nearly 9°) relative phase between the one-photon and the three-gluon decay amplitudes.

Final-state interaction phase difference inJ/ψ→ρηand ωη decays

It is shown that the study of the $\omega-\rho^0$ interference pattern in the $J/\psi\to (\rho^0+\omega)\eta\to\pi^+\pi^-\eta$ decay provides the evidence for the large (nearly $90^\circ$) relative phase between the one-photon and the three-gluon decay amplitudes.

Long-distance final-state interactions andJ/ψdecay

To understand the short- versus long-distance final-state interactions, we have performed a detailed amplitude analysis for the two-body decay J/{psi}{r_arrow}1{sup {minus}}0{sup {minus}}. The current data favor a large relative phase nearly 90{degree} between the three-gluon and the one-photon decay amplitudes. The source of the phase is apparently the long-distance final-state interaction. Nothing anomalous is found in the magnitudes of the three-gluon and one-photon decay amplitudes. We discuss the implications of this large phase in the weak decay of heavy particles. {copyright} {ital 1998} {ital The American Physical Society}

Random Response to Periodic Excitation with Correlated Disturbances

The paper addresses non-Gaussian stationary response of linear single-degree-of-freedom (SDOF) systems subject to a periodic excitation with correlated random amplitude and phase disturbances that are modeled as correlated Gaussian white noise processes. Correlation between amplitude and phase modulation is specified by the cross-correlation coefficient. Numerical results for the second and fourth moment responses are presented. The probability density function of the response is calculated based on the cumulant-neglect closure method. Non-Gaussian nature of the response is discussed in terms of the excess factor. The results show that the moment responses generally increase with larger random amplitude disturbance and may decrease with larger random phase modulation for a lightly damped system at resonance. The cross correlation between amplitude and phase disturbances plays an important role in the system moment response. Larger system damping results in smaller system moment responses. The moment response may approach a limiting value, depending on the intensity of the amplitude disturbance, as the relative detuning or phase modulation increases. For the case of the phase modulation alone, the response may become Gaussian in the sense of up to the fourth-order moment for sufficiently large relative detuning or random phase disturbances.