Analysis on B → VV with the Flavour SU（3） Symmetry

It is noted that the rescattering and annihilation effects are significant in the penguin-dominant B→ VV decays. In this work, we suggest to use a unique operator at the quark level to describe all the rescattering and the penguin-induced annihilation effects in B→ φK^＊, and the coefficient of the operator depends on the polarizations of the produced mesons. By the flavour SU（3） symmetry, we apply the same scenario to all the penguin-dominant B0190 VV modes.     

Properties of Dihadron Correlations for p＋p Collisions at √8NN = 200 GeV

The dihadron azimuthal angular correlations for p＋p collisions at √8NN = 200 GeV are simulated by a multiphase transport model. The dispersions of near-side and away-side peaks, indicated by the width of Gaussian fit functions and the rms width, decrease with the transverse momentum of associated particles. This trend is consistent with the experimental results. Conditional-yields are also calculated to obtain distributions of the associated particle transverse momentum for both away-side and near-side. Furthermore, the hadronic rescattering effects make the conditional-yield distributions softer.     

Properties of Dihadron Correlations for p+p Collisions at √sNN= 200 GeV

The dihadron azimuthal angular correlations for p+p collisions at√s_NN=200 GeV are simulated by a multi-phase transport model. The dispersions of near-side and away-side peaks, indicated by the width of Gaussian fit functions and the rms width, decrease with the transverse momentum of associated particles. This trend is consistent with the experimental results. Conditional-yields are also calculated to obtain distributions of the associated particle transverse momentum for both away-side and near-side. Furthermore, the hadronic rescattering effects make the conditional-yield distributions softer.     

Photon Radiation Induced by Multiple Parton Rescattering in Deeply Inelastic Scattering

Photon radiation induced by multiple parton rescattering and corresponding parton energy loss in eA deeply inelastic scattering are investigated by using the generalized factorization of higher twist parton distributions beyond the helicity amplitude approximation.It turns out that the behaviour fo the nuclear size dependence of the parton energy loss is different in the photon and gluon radiation cases.The parton energy loss due to photon radiation depends linearly,instead of quadratically,on nuclear size due to gluon radiation.     

Asymmetric structure of atomic above-threshold ionization spectrum in two-color elliptically polarized laser fields

According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization; while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels.     

Effect of multiple rescattering processes on harmonic emission in spatially inhomogeneous field

The effect of multiple rescattering processes on the harmonic emission from He atom in a spatially inhomogeneous field is discussed by solving the one-dimensional time-dependent Schr?dinger equation and the classical equation of motion.By establishing the physical model of the harmonic emission in the inhomogeneous field, we discuss the related characters of the multiple rescatterings process in the harmonic generation process. It shows that the second rescattering rather than the first rescattering tends to determine the harmonic cutoff energy when the inhomogeneous parameter is larger than 0.0055.Additionally, with the classical simulation, the underlying physical mechanism of the continuum–continuum harmonics is also revealed. Moreover, this work may provide new physical insight into the harmonic generation in an inhomogeneous field, and is beneficial to further extract the harmonic emission from molecular systems.     

Evidence of potential change in nonsequential double ionization

Recently,the quantitative rescattering model(QRS)for nonsequential double ionization(NSDI)is modified by taking into account the potential change(PC)due to the presence of electric field at the time of recollision.Using the improved QRS model,we simulate the longitudinal momentum distributions of doubly charged ions He2+by projecting the correlated two-electron momentum distributions for NSDI of He onto the main diagonal.The obtained results are compared directly with the experimental data at different intensities.It is found that when the PC is considered,the width of momentum distributions reduces and the agreement between theory and experiment is improved.     

Polarization and exchange effects in elastic scattering of electron with atoms and ions

Laser-induced electron diffraction(LIED), in which elastic scattering of the returning electron with the parent ion takes place, has been used to extract atomic potential and image molecular structures with sub-?A precision and exposure time of a few femtoseconds. So far, the polarization and exchange effects have not been taken into account in the theoretical calculation of differential cross section(DCS) for the laser-induced rescattering processes. However, the validity of this theoretical treatment has never been verified. In this work, we investigate the polarization and exchange effects on electron impact elastic scattering with rare gas atoms and ions. It is found that, while the exchange effect generally plays a more important role than the polarization effect in the elastic scattering process, the exchange effect is less important on electron–ion collisions than on electron–atom collisions, especially for scattering in backward direction. In addition, our calculations show that, for electron–atom collisions at incident energies above 50 e V, both the polarization and exchange effects can be safely neglected, while for electron–ion collisions, both the polarization and exchange potentials do not make substantial contributions to the DCS at incident energies above 20 e V and scattering angles larger than 90?. Our investigation confirms the validity of the current LIED method.     

Molecular Nature of X(3872) in B0→ K0X (3872) and B+→ K+X (3872) Decays

We investigate the decays of B⁰→ K⁰X(3872) and B⁺→ K⁺X(3872) based on the picture where the X(3872) resonance is strongly coupled to the ■+ c.c. channel. In addition to the decay mechanism where the X(3872) resonance is formed from the ■ pair hadronization with the short-distance interaction, we have also considered the ■ rescattering diagrams in the long-distance scale, where D and ■ are formed from c and ■ separately. Because of the difference of the...     

Multiple-plateau structure and scaling relation in photoelectron spectra of high-order above-threshold ionization

By developing a full quantum scattering theory of high-order above-threshold ionization,we study the energy spectra and the angular distributions of photoelectrons from atoms with intense laser fields shining on them.We find that real rescattering can occur many times,and even infinite times.The photoelectrons from the rescattering process form a broad plateau in the kinetic-energy spectrum.We further disclose a multiple-plateau structure formed by the high-energy photoelectrons,which absorb many photons during the rescattering process.Moreover,we find that both the angular distributions and the kinetic-energy spectra of photoelectrons obey the same scaling law as that for directly emitted photoelectrons.     

Electron Temperature Gradient Driven Instability in High Beta Plasmas of a Sheared Slab

Neglecting the magnetic gradient drift effects, we derive a simplified version of the integral eigenvalue equations for perturbations of electrostatic potential, and the perpendicular and parallel components of magnetic vector potential in plasmas of sheared slab geometry. The electron temperature gradient (ETG) instability in high beta plasmas is studied with the equations and the corresponding computer code. The preliminary results indicate that the coupling to perturbation of the perpendicular component of the magnetic vector potential has strong destabilization effects on ETG instabilities in contrast to the stabilization effects from the coupling to that of the parallel component when the magnetic gradient drift is not taken into account.     

Detuning Effects in the One-Photon Mazer

A theoretical approach is proposed to deal with the detuning between the atom and cavity field in the one-photon mazer. Our starting point is to find a conserved quantity, which is characteristic of the atom plus field system. Resorting to this characteristic conserved quantity, we separate the Hamiltonian into two independent parts and then solve the Schr6dinger equation of quantum scattering of an incident cold atom. We investigate the detuning effects on the one-photon induced emission probability and obtain some distinct results in contrast to the previous work.     

Energy cooperation in quantum thermoelectric systems with multiple electric currents

The energy efficiency and output power of a quantum thermoelectric system with multiple electric currents and only one heat current are studied.The system is connected to the hot heat bath(cold bath)through one terminal(multiple terminals).In such configurations,there are multiple thermoelectric effects coexisting in the system.Using the Landauer–Buttiker formalism,we show that the cooperation between the two thermoelectric effects in the three-terminal thermoelectric systems can lead to markedly improved performance of the heat engine.Such improvement also occurs in four-terminal thermoelectric heat engines with three output electric currents.Cooperative effects in these multi-terminal thermoelectric systems can considerably enlarge the physical parameter region that realizes high energy efficiency and output power.For refrigeration,we find that the energy efficiency can also be substantially improved by exploiting the cooperative effects in multi-terminal thermoelectric systems.All these results reveal a useful approach toward high-performance thermoelectric energy conversion in multi-terminal mesoscopic systems.     

Triple plasmon-induced transparency and outstanding slow-light in quasi-continuous monolayer graphene structure

We propose a simple quasi-continuous monolayer graphene structure and achieve a dynamically tunable triple plasmon-induced transparency(PIT)effect in the proposed structure.Additional analyses indicate that the proposed structure contains a selfconstructed bright-dark-dark mode system.A uniform theoretical model is introduced to investigate the spectral response characteristics and slow light-effects in the proposed system,and the theoretical and the simulated results exhibit high consistency.In addition,the influences of the Fermi level and the carrier mobility of graphene on transmission spectra are discussed.It is found that each PIT window exhibits an independent dynamical adjustability owing to the quasi-continuity of the proposed structure.Finally,the slow-light effects are investigated based on the calculation of the group refractive index and phase shift.It is found that the structure displays excellent slow-light effects near the PIT windows with high-group indices,and the maximum group index of each PIT window exceeds 1000 when the carrier mobility of graphene increases to 3.5 m^2 V^-1s^-1.The proposed structure has potential to be used in multichannel filters,optical switches,modulators,and slow-light devices.Additionally,the established theoretical model lays a theoretical basis for research on multimode coupling effects.     

Double ionization of helium interacting with elliptically polarized laser pulse by classical ensemble simulations

This paper uses the classical ensemble method to study the double ionization of a 2-dimensional (2D) model helium atom interacting with an elliptically polarized laser pulse. The classical ensemble calculation demonstrates that the ratio of double to single ionization decreases with the increasing ellipticity of the driving field. The classical scenario shows that there are hardly any e--e recollisions with the circularly polarized laser pulse. The double ionization probability is studied for linearly and circularly polarized laser pulses. The classical numerical results are consistent with the semiclassical rescattering mechanism and in agreement with the experimental results and the quantum calculations qualitatively.     

Interference phase of mass neutrino in Reissner-Nordstrm-de Sitter space-time

In Reissner--Nordstr?m--de Sitter space--time, we calculate the interference phase of mass neutrino along geodesic in the radial direction, and then investigate the effects of the cosmological constant La on the phase. Morever, the expression of the interference phase can be reduced to that in Reissner--Nordstr?m space--time when Λ approaches to zero.     

Observation of photon recoil effects in single-beam absorption spectroscopy with an ultracold strontium gas

We report on observing photon recoil effects in the absorption of a single monochromatic light at 689 nm through an ultracold ⁸⁸Sr gas,where the recoil frequency is comparable to natural linewidth of the narrow-line transition 5s^{2 1}S₀-5s5p ³P₁ in strontium.In the regime of high-saturation,the absorption profile becomes asymmetric due to the photon-recoil shift,which is of the same order as the natural linewidth.The lineshape is described by an extension of the optical Bloch equations including the momentum transfers to atoms during emission and absorption of photons.Our work reveals the photon recoil effects in a simplest single-beam absorption setting,which is of significant relevance to other applications such as saturation spectroscopy,Ramsey interferometry,and absorption imaging.     

Effects of sea surface temperature, cloud radiative and microphysical processes, and diurnal variations on rainfall in equilibrium cloud-resolving model simulations

The effects of sea surface temperature(SST),cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model simulations.For a rain rate of higher than 3 mm.h 1,water vapor convergence prevails.The rainfall amount decreases with the decrease of SST from 29℃ to 27℃,the inclusion of diurnal variation of SST,or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds,which are primarily associated with the decreases in water vapor convergence.However,the amount of rainfall increases with the increase of SST from 29℃ to 31℃,the exclusion of diurnal variation of solar zenith angle,and the exclusion of the radiative effects of ice clouds,which are primarily related to increases in water vapor convergence.For a rain rate of less than 3 mm.h 1,water vapor divergence prevails.Unlike rainfall statistics for rain rates of higher than 3 mm.h 1,the decrease of SST from 29℃ to 27℃ and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount,which corresponds to the suppression in water vapor divergence.The exclusion of microphysical effects of ice clouds decreases the amount of rainfall,which corresponds to the enhancement in water vapor divergence.The amount of rainfall is less sensitive to the increase of SST from 29℃ to 31℃ and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds.