118483093
Spectrum for heavy quarkonia and mixture of the relevant wave functions within the framework of Bethe-Salpeter equation
Considering the fact that some excited states of the heavy quarkonia (charmonium and bottomonium) are still missing in experimental observations and potential applications of the relevant wave functions of the bound states, we re-analyze the spectrum and the relevant wave functions of the heavy quarkonia within the framework of Bethe-Salpeter (B.S.) equation with a proper QCD-inspired kernel. Such a kernel for the heavy quarkonia, relating to potential of the non-relativistic quark model, is instantaneous, so we call the corresponding B.S. equation as BS-In equation throughout the paper. Particularly, a new way to solve the B.S. equation, which is different from the traditional ones, is proposed here, and with it not only the known spectrum for the heavy quarkonia is re-generated, but also an important issue is brought in, i.e., the obtained solutions of the equation ‘automatically’ include the ‘fine’, ‘hyperfine’ splittings and the wave function mixture, such as S-D wave mixing in JPC = 1−− states, P-F wave mixing in JPC = 2++ states for charmonium, bottomonium etc. It is pointed out that the best place to test the wave mixture probably is at Z-factory (e+e− collider running at Z-boson pole with extremely high luminosity).
15948978
The Pure Leptonic Decays of $D_s$ Meson and Their Radiative Corrections
The radiative corrections to the pure leptonic decay $D_s{\longrightarrow} {\ell}{{\nu}}_{\ell}$ up-to one-loop order is presented. We find the virtual photon loop corrections to $D_s{\longrightarrow} {\tau}{{\nu}}_{\tau}$ is negative and the corresponding branching ratio is larger than $3.51\times 10^{-3}$. Considering the possible experimental resolutions, our prediction of the radiative decay $D_s{\longrightarrow} {\tau}{{\nu}}_{\tau}\gamma$ is not so large as others, and the best channel to determine the $V_{cs}$ or $f_{D_s}$ is $D_s{\longrightarrow} {\mu}{{\nu}}_{\mu}{\gamma}$. How to cancel the infrared divergences appearing in the loop calculations, and the radiative decay $D_s{\longrightarrow} {\ell}{{\nu}}_{\ell}{\gamma}$ is shown precisely. It is emphasized that the radiative decay may be separated properly and may compare with measurements directly as long as the theoretical `softness' of the photon corresponds to the experimental resolutions.
119300428
Why X(3915) is so narrow as a $\chi_{c0}(2P)$ state
New resonance X(3915) was identified as the charmonium $\chi_{c0}(2P)$ by BABAR Collaboration, but there seems still open question of this assignment: why its full width is so narrow? To answer this question, we calculate the Okubo-Zweig-Iizuka (OZI) allowed strong decays $X(3915)\to D \bar D$, where X(3915) is assigned as a $\chi_{c0}(2P)$ state, and estimate its full width in the cooperating framework of $^3/!P_0^{}$ model and the Bethe-Salpeter (BS) method using the Mandelstam Formalism, during which non-perturbative QCD effects of the hadronic matrix elements are well considered by overlapping integral over the relativistic Salpeter wave functions of the initial and finial states. We find the node structure of $\chi_{c0}(2P)$ wave function resulting in the narrow width of X(3915) and show the dependence of the decay width on the variation of the initial mass of X(3915). We point out that the rate of $\frac{\Gamma(X(3915)\to D^+ D^-)}{\Gamma(X(3915)\to D^0 \bar D^0)}$ is crucial to confirm whether X(3915) is the $\chi_{c0}(2P)$ state or not.
119163636
Decay constants of P-wave mesons
Abstract Decay constants of P-wave mesons are computed in the framework of instantaneous Bethe–Salpeter method (Salpeter method). By analyzing the parity and possible charge conjugation parity, we give the relativistic configurations of wave functions with definite parity and possible charge conjugation parity. With these wave functions as input, the full Salpeter equations for different P-wave states are solved, and the mass spectra as well as the numerical values of wave functions are obtained. Finally we compute the leptonic decay constants of heavy–heavy and heavy–light P 0 3 , P 1 3 and P 1 1 states.
14177196
The Layer Phase in the Non-isotropic SU(3) Gauge Model at Finite Temperature
The phase structure of a non-isotropic non-Abelian SU(3) lattice gauge model at finite temperature is investigated to the third order in the variational-cumulant expansion (VCE) approach. The layer phase exists in this model in the cases of dimensions D=4, D=5 (d=D-1).
123969406
Semileptonic Production of Scalar and Tensor p-Wave Charmed Mesons
With the same constituents of quark and antiquark, the p-wave state has a higher mass than the corresponding s-wave state, but the relativistic corrections are much larger in the processes of which p-wave mesons are involved. Considering this, the relativistic Bethe?Salpeter method is applied to estimate the branching fractions of semileptonic decays B(s) ? D*(sJ)l? (J = 0,2). Our predictions are Br[???(2317)l?]?=?0.50%, Br[???(2573)l?]?=?0.40%, Br[B????(2400)l?]?=?0.79%, Br[B????(2460)l?]?=?0.28%, Br[???(2400)l?]?=?0.58% and Br[???(2460)l?]?=?0.27%. .
112824375
Energy Recovery Transport Design for Peking University FEL
A free-electron laser based on a superconducting linac is under construction in Peking University. To increase FEL output power, energy recovery is chosen as one of the most potential and popular ways. The design of a beam transport system for energy recovery is presented, which is suitable for the Peking University construction area. Especially, a chicane structure is chosen to change path length at ±20 degree and M56 in the arc is adjusted for fully bunch compression.
119296513
Measurements of heavy flavor and di-electron production at STAR
Heavy quarks are produced early in the relativistic heavy ion collisions, and provide an excellent probe into the hot and dense nuclear matter created at RHIC. In these proceedings, we will discuss recent STAR measurements of heavy flavor production, to investigate the heavy quark interaction with the medium. Electromagnetic probes, such as electrons, provide information on the various stages of the medium evolution without modification by final stage interactions. Di-electron production measurements by STAR will also be discussed.
120552860
The topological basis realization and the corresponding XXX spin chain
In this paper, it is shown that the XXX model can be constructed from the Temperley-Lieb algebra (TLA) generator. We find that the topological basis states are the two eigenstaes of a closed four-qubit Heisenberg XXX spin chain. Specifically, the spin single states and the energy single state of the system all fall on the topological basis states. It is worth mentioning that for the closed 2N-qubit (N=2, 3, 4, ...) Heisenberg XXX spin chain, all the topological basis states for 2N particles are the spin single states of the system. And the number of the topological basis states is equal to the number of the spin single states of the system, which is .
119169539
Elliptic flow in the Gaussian model of eccentricity fluctuations
Abstract We discuss a specific model of elliptic flow fluctuations due to Gaussian fluctuations in the initial spatial x and y eccentricity components { 〈 ( σ y 2 − σ x 2 ) / ( σ x 2 + σ y 2 ) 〉 , 〈 2 σ x y / ( σ x 2 + σ y 2 ) 〉 } . We find that in this model v 2 { 4 } , elliptic flow determined from 4-particle cumulants, exactly equals the average flow value in the reaction plane coordinate system, 〈 v RP 〉 , the relation which, in an approximate form, was found earlier by Bhalerao and Ollitrault in a more general analysis, but under the same assumption that v 2 is proportional to the initial system eccentricity. We further show that in the Gaussian model all higher order cumulants are equal to v 2 { 4 } . Analysis of the distribution in the magnitude of the flow vector, the Q -distribution, reveals that it is totally defined by two parameters, v 2 { 2 } , the flow from 2-particle cumulants, and v 2 { 4 } , thus providing equivalent information compared to the method of cumulants. The flow obtained from the Q -distribution is again v 2 { 4 } = 〈 v RP 〉 .
119253082
Non-photonic electron-hadron correlations and non-photonic electron v2 at STAR/RHIC
Abstract Non-photonic electrons ( p T > 3 GeV / c ) represent the directions of the parent heavy quarks, and their angular correlations with charged hadrons provide a good tool to study the relative contributions from D and B meson decays in p+p collisions, as well as the flavor-dependence of the energy loss mechanism in A+A collisions. We review the disentanglement of charm and bottom contributions to non-photonic electrons in p+p collisions at s = 200 GeV at RHIC. B decay contribution is approximately 50% at the electron transverse momentum of p T > 5 GeV / c from STAR results. Incorporating the energy loss ( R AA ) information of non-photonic electrons, the result indicates a B meson suppression at high p T in heavy ion collisions. We also present non-photonic electron-hadron correlations in d+Au collisions as a baseline reference for the investigation of the heavy quark energy loss in A+A collisions. The interactions between heavy quarks and the QCD medium can lead to a non-zero “elliptic flow” parameter ( v 2 ) of D and B mesons which can be studied through v 2 of non-photonic electrons. Preliminary v 2 measurements for non-photonic electrons are shown to be lower than v 2 of charged hadrons (or K S 0 , Λ ) for 200 GeV Au+Au collisions.