Study on the structure of the four-quark states in terms of the Born-Oppenheimer approximation

In this work, we use the Born-Oppenheimer approximation where the potential between atoms can be approximated as a function of distance between the two nuclei to study the four-quark bound states. By the approximation, Heitler and London calculated the spectrum of hydrogen molecule which includes two protons (heavy) and two electrons (light). Generally, the observed exotic mesons $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$ and $Z_c(4020)$($Z_c(4025)$) may be molecular states made of two physical mesons and/or in diquark-anti-diquark structures. In analog to the Heitler-London method for calculating the mass of hydrogen molecule, we investigate whether there exist energy minima for these two structures. By contrary to the hydrogen molecule case where only the spin-triplet possesses an energy minimum, there exist minima for both of them. It implies that both molecule and tetraquark states can be stable objects. But since they have the same quantum numbers, the two states may mix to result in the physical states. A consequence would be that partner exotic states co-existing with $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$ and $Z_c(4020)$($Z_c(4025)$) are predicted and should be experimentally observed.Comment: 13 pages, 10 figure

Revisiting the OZI-forbidden Radiative Decays of Orthoquarkonia

It is interesting to investigate the OZI-forbidden radiative orthoquarkonium decays $J/\psi\to \gamma\pi^0, \gamma\eta$ and $\gamma\eta'$ in perturbative QCD. In this work without the approximations adopted in literature we carry out a full one-loop calculation which involves integrations of 4-point and 5-point loop functions. Our numerical results are in agreement with the present data. We also briefly discuss the decays of $J/\psi\to \gamma+\rho^0$, as well as $\Upsilon\to \pi^0\gamma, \eta\gamma, \eta'\gamma$.Comment: 18pages,2figures;final version to appear in Nucl.Phys.

M Times Photon Subtraction-Addition Coherent Superposition Operated Odd-Schr\H{o}dinger-cat State: Nonclassicality and Decoherence

We introduce a new non-Gaussian state, generated by m times coherent superposition operation $a\cos \theta +a^{\dagger }e^{i\varphi }\sin \theta$ (MCSO) on odd-Schrodinger-cat state (OSCS). Its normalized constant is turned out to be related with the Hermite polynomial. We further investigate the nonclassical properties of the MCSO-OSCS through Mandel's Q-parameter, quadrature squeezing, the photocount distribution and Wigner function (WF). It is shown that the nonclassicality of the MCSO-OSCS is influenced by the number of times (m) of coherent superpositon operation, the angle $\theta$ and the amplitude of the coherent state (|$\alpha _{0}$|). Especially the volume of negative region of WF increases with the increment of parameters m, $\theta$ and $\alpha _{0}$. We also investigate the decoherence of the MCSO-OSCS in terms of the fadeaway of the negativity of WF in a thermal environment.Comment: 14 pages with 10 figure

Revisiting non-Gaussianity of multiple-field inflation from the field equation

In the present paper, we study the non-Gaussianity of multiple-field inflation model using the method of the field equation. We start from reviewing the background and the perturbation theory of multiple-field inflation, and then derive the Klein-Gorden equation for the perturbations at second order. Afterward, we calculate the tree-level bispectrum of the fields' perturbations and finally give the corresponding parameter $f_{NL}$ for the curvature perturbation $\zeta$ in virtue of the $\delta N$ formalism. We also compare our result with the one already obtained from the Lagrangian formalism, and find they are consistent. This work may help us understand perturbation theory of inflation more deeply.Comment: 19 page

Affect Sensing on Smartphone - Possibilities of Understanding Cognitive Decline in Aging Population

Due to increasing sensing capacity, smartphones offer unprecedented opportunity to monitor human health. Affect sensing is one such essential monitoring that can be achieved on smartphones. Information about affect can be useful for many modern applications. In particular, it can be potentially used for understanding cognitive decline in aging population. In this paper we present an overview of the existing literature that offer affect sensing on smartphone platform. Most importantly, we present the challenges that need to be addressed to make affect sensing on smartphone a reality.Comment: This paper has been withdrawn due to some conceptual erro

Modeling citation networks based on vigorousness and dormancy

In citation networks, the activity of papers usually decreases with age and dormant papers may be discovered and become fashionable again. To model this phenomenon, a competition mechanism is suggested which incorporates two factors: vigorousness and dormancy. Based on this idea, a citation network model is proposed, in which a node has two discrete stage: vigorous and dormant. Vigorous nodes can be deactivated and dormant nodes may be activated and become vigorous. The evolution of the network couples addition of new nodes and state transitions of old ones. Both analytical calculation and numerical simulation show that the degree distribution of nodes in generated networks displays a good right-skewed behavior. Particularly, scale-free networks are obtained as the deactivated vertex is target selected and exponential networks are realized for the random-selected case. Moreover, the measurement of four real-world citation networks achieves a good agreement with the stochastic model.Comment: ws-tex, 11 pages, 5 figure

Temporal scaling in information propagation

For the study of information propagation, one fundamental problem is uncovering universal laws governing the dynamics of information propagation. This problem, from the microscopic perspective, is formulated as estimating the propagation probability that a piece of information propagates from one individual to another. Such a propagation probability generally depends on two major classes of factors: the intrinsic attractiveness of information and the interactions between individuals. Despite the fact that the temporal effect of attractiveness is widely studied, temporal laws underlying individual interactions remain unclear, causing inaccurate prediction of information propagation on evolving social networks. In this report, we empirically study the dynamics of information propagation, using the dataset from a population-scale social media website. We discover a temporal scaling in information propagation: the probability a message propagates between two individuals decays with the length of time latency since their latest interaction, obeying a power-law rule. Leveraging the scaling law, we further propose a temporal model to estimate future propagation probabilities between individuals, reducing the error rate of information propagation prediction from 6.7% to 2.6% and improving viral marketing with 9.7% incremental customers.Comment: 13 pages, 2 figures. published on Scientific Report

Search for Ambient Neutralino Dark Matter at Accelerator

We investigate the possibility of using accelarator beam particles to collide with the ambient neutralino dark matter particles in cosmic rays as a way to search for the cold dark matter. We study in detail its inelastic and elastic scattering with the projectile particles at electron-positron colliders and discuss the possible experimental signals and the relevent background.Comment: 8 page

A method to constrain mass and spin of GRB black hole within the NDAF model

Black holes (BHs) hide themselves behind various astronomical phenomena, and their properties, i.e., mass and spin, are usually difficult to constrain. One leading candidate for the central engine model of gamma-ray bursts (GRBs) invokes a stellar mass BH and a neutrino-dominated accretion flow (NDAF), with the relativistic jet launched due to neutrino-anti-neutrino annihilations. Such a model gives rise to a matter-dominated fireball, and is suitable to interpret GRBs with a dominant thermal component with a photospheric origin. We propose a method to constrain BH mass and spin within the framework of this model, and apply the method to a thermally-dominant GRB 101219B whose initial jet launching radius $r_0$ is constrained from the data. Using our numerical model of NDAF jets, we estimate the following constraints on the central BH: mass $M_{\rm BH} \sim 5-9~M_\odot$, spin parameter $a_* \gtrsim 0.6$, and disk mass $3~M_\odot \lesssim M_{\rm disk} \lesssim 4~M_\odot$. Our results also suggest that the NDAF model is a competitive candidate for the central engine of GRBs with a strong thermal component.Comment: 5 pages, 3 figures, accepted for publication in Ap

The annihilation decays Bc−→η′(η,π0)l−νˉB^-_c \to \eta^{'}(\eta ,\pi^0) l^- \bar{\nu}

We investigate the simileptonic OZI-forbidden annihilation decays $B^-_c \to \eta^{'}(\eta ,\pi^0) l^- \bar{\nu}$ for $l=\mu,e$ in the perturbative QCD, and carry out a precise calculation without any approximation for the one-loop contributions, which involves integrals of 4- and 5-point loop functions. Our results show that the branching ratios of decays $B^-_c \to \eta^{'} l^- \bar{\nu}$, $B^-_c \to \eta l^- \bar{\nu}$ and $B^-_c \to \pi^0 l^- \bar{\nu}$, turn out to be of orders $10^{-4}$, $10^{-5}$ and $10^{-6}$, respectively, which could be observable in the future experiments at the LHC.Comment: 15 pages, 1 figures. To be appeared in Phys.Rev.