arXiv subjects

Xiao-Yun Wang

Publications and source records attributed to Xiao-Yun Wang.

64 records · Page 4Linked to original sources

arXiv2016

The $K^{\ast 0}Λ$ photoproduction off a neutron

Inspired by the preliminary experimental data by the CLAS Collaboration, the $K^{\ast 0}Λ$ photoproduction off a neutron is studied within an effective Lagrangian approach. The contributions from the Born terms including $s$, $u$, and $t$ channels are considered to calculate the amplitude, with which the cross sections are calculated and compared with preliminary CLAS data. The theoretical results indicate that the contribution from the $K$-exchange $t$ channel plays a dominant role for the $K^{\ast 0}Λ$ photoproduction. The contribution from the $κ$ exchange is found one order of magnitude smaller than that from the $K$ exchange. Both the Regge model and the Feynman model are applied to treat the $t$-channel contribution. The discrepancy between two models is found small in the energy range of CLAS data and predicted to become obvious at energies higher than 3 GeV. More precise experimental data especially at backward angles will be helpful to further understand the interaction mechanism of the $K^{\ast 0}Λ$ photoproduction.

nucl-th↗

arXiv2016

Photoproduction of $a_{2}(1320)$ in a Regge model

In this work, the photoproduction of $a_{2}(1320)$ off a proton target is investigated within an effective Lagrangian approach and the Regge model. The theoretical result indicates that the shapes of {the} total and differential cross sections of the $γp\rightarrow a_{2}^{+}n$ reaction within the Feynman (isobar) model are much different from that of the Reggeized treatment. The obtained cross section is compared with the existing experimental results at low energies. The $a_{2}(1320)$ production cross section at high energies can be tested by the COMPASS experiment, which can provide important information for clarifying the role of the Reggeized treatment at that energy range.

hep-ph↗

arXiv2015

Charmed hadron photoproduction at COMPASS

Photoproduction of the charmonium-like state $Z_{c}(4200)$ and the charmed baryon $Λ_{c}^{\ast }(2940)$ is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of $Γ_{Z_{c}(4200)\rightarrow J/ψπ}$ to be of about 37 MeV. Moreover, the possibility to produce $Λ_{c}^{\ast }(2940)$ at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the $t$-channel is dominating for the $Λ_{c}^{\ast }(2940)$ photoproduction.

hep-ph↗

arXiv2015

Neutral hidden charm pentaquark states $P_c^0(4380)$ and $P_c^0(4450)$ in $π^-p \to J/ψn$ reaction

We investigate the neutral hidden charm pentaquark states $P_c^0(4380)$ and $P_c^0(4450)$ in $π^-p \to J/ψn$ reaction within an effective Lagrangian approach. The background contributions for the process mainly come from $t$-channel $π$ and $ρ$ meson exchanges. The contributions of $P_c^0(4380)$ and $P_c^0(4450)$ states give clear peak structures in the magnitude of 1 $μ$b at center of mass energy 4.38 GeV and 4.45 GeV in the total cross sections. Hence, this reaction may provide a new good platform to search for neutral $P_c$ states. It is expected that our estimated total cross sections together with the angular distributions can be tested by future experiments at J-PARC.

hep-ph↗

arXiv2015

Reexamination of the role of the $Δ^{\ast}$ resonances in the $pp\rightarrow nK^{+}Σ^{+}$ reaction

In this work, the role of the $Δ^{\ast }$ resonances in the process of $pp\rightarrow nK^{+}Σ^{+}$ are systematically investigated with the effective Lagrangian approach and the isobar model. We find that a $P_{31}$ state, either $Δ^{\ast }(1750)$ or $Δ^{\ast }(1910)$, is favored by the data while the $P_{33}$ state, namely $Δ^{\ast }(1920)$, has small contribution. Besides, either sub-threshold $S_{31}$ $Δ^{\ast }(1620)$ resonance or strong $nΣ$ final state interaction or both have possible contribution at near threshold region, depending on the measured cross sections. We demonstrate the invariant mass distributions and the Dalitz Plots in order to investigate whether it is possible to distinguish the controversial $KΣ$ production mechanism in these observables.

nucl-th↗

arXiv2015

$Λ_{c}^{+}(2940)$ photoproduction off the neutron

By assuming that the $Λ_{c}^{\ast }(2940)$ is a $pD^{\ast 0}$ molecular state with spin-parity $J^{P}=\frac{1}{2}^{+}$ and $J^{P}=\frac{1}{2}^{-}$, the photoproduction of charmed $Λ_{c}^{\ast }(2940)$ baryon in the $γn\rightarrow D^{-}Λ_{c}^{\ast }(2940)^{+}$ process is investigated with an effective Lagrangian approach. It is found that the contributions from $t$-channel with $D^{\ast }$ exchange are dominant, while the $s$-channel with nucleon pole exchange give a sizeable contribution around the threshold. The contributions from the $u$-channel and contact term are very small. The total cross section of the $γn\rightarrow D^{-}Λ_{c}^{\ast }(2940)^{+}$ reaction is estimated, which indicate it is feasible to searching for the charmed $Λ_{c}^{\ast }(2940)$ baryon at the COMPASS experiment.

hep-ph↗

arXiv2015

Production of the superheavy baryon $Λ_{c\bar{c}}^{\ast}(4209) $ in kaon-induced reaction

The production of superheavy $Λ_{c\bar{c}}^{\ast }(4209)$ baryon in the $K^{-}p\rightarrow η_{c}Λ$ process via $s$-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the $t$-channel with $K^{\ast }$ and $u$-channel with nucleon exchange are also considered, which are regarded as the background for the $Λ_{c\bar{c}}^{\ast }(4209)$ production in the $K^{-}p\rightarrow η_{c}Λ$ reaction. The numerical results indicate it is feasible to searching for the superheavy $Λ_{c\bar{c}}^{\ast }(4209)$ via $K^{-}p$ scattering. These theoretical results not only provide valuable informations to future experimental exploration of $Λ_{c\bar{c}}^{\ast }(4209)$ resonance but enable us to have a better understanding of the exotic baryons.

hep-ph↗

arXiv2015

Discovery potential for the neutral charmoniumlike $Z^{0}(4200)$ by $\bar{p}p$ annihilation

Inspired by the observation of charmoniumlike $Z(4200)$, we explore the discovery potential of the neutral $Z^{0}(4200)$ production by antiproton-proton annihilation with an effective Lagrangian approach. By investigating the $\bar{p}p\rightarrow J/ψπ^{0}$ process including the $Z^{0}(4200)$ signal and background contributions, it is found that the center of mass energy $E_{c.m.}\simeq 4.0-4.5$ GeV is the best energy window for searching the neutral $Z^{0}(4200)$, where the signal can be clearly distinguished from background. The relevant calculations is not only helpful to search for the neutral $Z^{0}(4200)$ in the future experiment, but also will promote the understanding the nature and production mechanism of neutral $Z^{0}(4200)$ better.

hep-ph↗

arXiv2015

Photoproduction of the charged charmoniumlike $Z_{c}^{+}(4200)$

In this work, inspired by the observation of charmoniumlike $Z_{c}^{+}(4200)$% , we study the photoproduction of charged charmoniumlike $Z_{c}^{+}(4200)$ with an effective Lagrangian approach and the Regge trajectories model. The numerical results indicate that the Reggeized treatment can lead to a lower total cross section of the $Z_{c}^{+}(4200)$ photoproduction and the peak position of cross section was moved to the higher energy point when the Reggeized treatment was added. {Moreover, using the data from the COMPASS experiment and presented theoretical predictions, an upper limit of the decay width of $Z_{c}(4200)\rightarrow J/ψπ$ is estimated.} The relevant results not only shed light on the further experiment of searching for the charmoniumlike $Z_{c}(4200)$ state via meson photoproduction, but also provide valuable informations for having a better comprehension of the nature of charmoniumlike $Z_{c}(4200)$ state.

hep-ph↗

arXiv2015

Preserving Local Gauge Invariance with t-Channel Regge Exchange

Considering single-meson photo- and electroproduction off a baryon, it is shown how to restore local gauge invariance that was broken by replacing standard Feynman-type meson exchange in the t-channel by exchange of a Regge trajectory. This is achieved by constructing a contact current whose four-divergence cancels the gauge-invariance-violating contributions resulting from all states above the base state on the Regge trajectory. To illustrate the procedure, modifications necessary for the process $γ+p \to K^+ + Σ^{*0}$ are discussed in some detail. We also provide the general expression for the contact current for an arbitrary reaction.

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