arXiv subjects
Publications and source records attributed to Hong-Wei Ke.
We study the production of $Z^\pm(4430)$ at a nucleon-antinucleon scattering experiment. Considering the PANDA experiment to be an ideal platform to explore the production of the charmonium and charmonim-like states, we suggest the forthcoming PANDA experiment to pay attention to the production of $Z^\pm(4430)$.
In this work we evaluate the cross section of the process $e^+e^-\to J/ψη_c$ at energy $\sqrt{s}\approx 10.6$ GeV in the Bethe-Salpeter formalism. To simplify our calculation, the heavy quark limit is employed. Without taking the beyond-leading-order contribution(s) into account, the cross section calculated in this scenario is comparable with the experimental data. We also present our prediction for the cross section of double bottomonium production $e^+e^-\to Υ(1S)η_b$ for the energy range of $\sqrt{s}\approx (25 \hbox{-} 30)$ GeV which may be experimentally tested, even though there is no facility of this range available at present yet.
It is interesting to search for new physics beyond the standard model at LHCb. We suggest that weak decays of doubly charmed baryon such as $Ξ_{cc}(3520)^+, Ξ_{cc}^{++}$ to charmless final states would be a possible signal for new physics. In this work, we consider two models, i.e. the unparticle and $Z'$ as examples to study such possibilities. We also discuss the cases for $Ξ^0_{bb}, Ξ_{bb}^-$ which have not been observed yet, but one can expect to find them when LHCb begins running. Our numerical results show that these two models cannot result in sufficiently large decay widths, therefore if such modes are observed at LHCb, there must be a new physics other than the unparticle or $Z'$ models.
In this work we investigate the weak $Λ_{b}\toΛ_c$ semi-leptonic and non-leptonic decays. The light-front quark model and diquark picture for heavy baryons are adopted to evaluate the $Λ_{b}\toΛ_c$ transition form factors. In the heavy quark limit we study the Isgur-Wise function. By fitting the data of the semi-leptonic process we obtain the mass of the light scalar diquark as 817 MeV. The numerical predictions on the branching ratios of non-leptonic decay modes $Λ_{b}\toΛ_c M$ and various polarization asymmetries are made. A comparison with other approaches is discussed.
One of the most important tasks in high energy physics is search for the exotic states, such as glueball, hybrid and multi-quark states. The transitions $ψ(ns)\to ψ(ms)+ππ$ and $Υ(ns)\to Υ(ms)+ππ$ attract great attentions because they may reveal characteristics of hybrids. In this work, we analyze those transition modes in terms of the theoretical framework established by Yan and Kuang. It is interesting to notice that the intermediate states between the two gluon-emissions are hybrids, therefore by fitting the data, we are able to determine the mass spectra of hybrids. The ground hybrid states are predicted as 4.23 GeV (for charmonium) and 10.79 GeV (for bottonium) which do not correspond to any states measured in recent experiments, thus it may imply that very possibly, hybrids mix with regular quarkonia to constitute physical states. Comprehensive comparisons of the potentials for hybrids whose parameters are obtained in this scenario with the lattice results are presented.
In this work, we revisit the electron transfer rate theory, with particular interests in the distinct quantum solvation effect, and the characterizations of adiabatic/nonadiabatic and Markovian/non-Markovian rate processes. We first present a full account for the quantum solvation effect on the electron transfer in Debye solvents, addressed previously in J. Theore. & Comput. Chem. {\bf 5}, 685 (2006). Distinct reaction mechanisms, including the quantum solvation-induced transitions from barrier-crossing to tunneling, and from barrierless to quantum barrier-crossing rate processes, are shown in the fast modulation or low viscosity regime. This regime is also found in favor of nonadiabatic rate processes. We further propose to use Kubo's motional narrowing line shape function to describe the Markovian character of the reaction. It is found that a non-Markovian rate process is most likely to occur in a symmetric system in the fast modulation regime, where the electron transfer is dominant by tunneling due to the Fermi resonance.
In this work we use the heavy-quark-light-diquark picture to study the semileptonic decay $Λ_b \to Λ_c+l+\barν_l$ in the so-called hybrid scheme. Namely, we apply the heavy quark effective theory (HQET) for larger $q^2$ (corresponding to small recoil), which is the invariant mass square of $l+\barν$, whereas the perturbative QCD approach for smaller $q^2$ to calculate the form factors. The turning point where we require the form factors derived in the two approaches to be connected, is chosen near $ρ_{cut}=1.1$. It is noted that the kinematic parameter $ρ$ which is usually adopted in the perturbative QCD approach, is in fact exactly the same as the recoil factor $ω=v\cdot v'$ used in HQET where $v$, $v'$ are the four velocities of $Λ_b$ and $Λ_c$ respectively. We find that the final result is not much sensitive to the choice, so that it is relatively reliable. Moreover, we apply a proper numerical program within a small range around $ρ_{cut}$ to make the connection sufficiently smooth and we parameterize the form factor by fitting the curve gained in the hybrid scheme. The expression and involved parameters can be compared with the ones gained by fitting the experimental data. In this scheme the end-point singularities do not appear at all. The calculated value is satisfactorily consistent with the data which is recently measured by the DELPHI collaboration within two standard deviations.
The diquark structure in baryons is commonly accepted as a reasonable approximation which can much simplify the picture and reduce the length of calculations. However, a diquark by no means is a point-like particle, even though it is treated as a whole object. Therefore, to apply the diquark picture to the phenomenological calculations, at the effective vertices for the diquark-gauge boson interactions, suitable form factors must be introduced to compensate the effects caused by the inner structure of the diquark. It is crucial to derive the appropriate form factors for various interactions. In this work, we use the Bethe-Salpeter equation to derive such form factors and numerically evaluate their magnitudes.
The resonance $D_{sJ}(2632)$ observed by SELEX, has attracted great interests and meanwhile brought up serious dispute. Its spin-parity, so far has not finally determined and if it exists, its quark-structure might be exotic. Following the previous literature where $D_{sJ}(2632)$ is assumed to be a radial-excited state of $1^-$, we consider the possibilities that it might be a $q\bar q$ ground state of $2^+$ or the first radial-excited state of $0^+$ $D_{sJ}(2317)$ and re-calculate its strong decay widths in terms of the Bethe-Salpeter equation. Our results indicate that there still is a sharp discrepancy between the theoretical evaluation and data.
In this work, we employ the Bethe-Salpeter (B-S) equation to investigate the spectra of free diquarks and their B-S wave functions. We find that the B-S approach can be consistently applied to study the diqaurks with two heavy quarks or one heavy and one light quarks, but for two light-quark systems, the results are not reliable. There are a few free parameters in the whole scenario which can only be fixed phenomenologically. Thus, to determine them, one has to study baryons which are composed of quarks and diquarks.
The newly observed $D_{sJ}^*$ family containing $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ and $D_{sJ}(2632)$ attracts great interests. Determining their structure may be important tasks for both theorists and experimentalists. In this work we use the heavy quark effective theory (HQET) and a non-relativistic model to evaluate the production rate of $D_{sJ}^{*}(2317)$ from the decays of $ψ(4415)$, and we find that it is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of $D_s(1968)$. Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.