arXiv subjects

Xiang Liu

Publications and source records attributed to Xiang Liu.

655 records · Page 37Linked to original sources

arXiv2005

Study on production of exotic $0^+$ meson $D_{sJ}^{*}(2317)$ in decays of $ψ(4415)$

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.

hep-ph↗

arXiv2005

Possible Molecular Structure of the Newly Observed Y(4260)

We suggest that the newly observed resonance Y(4260) is a $χ_{c}-ρ^0$ molecule, which is an isovector. In this picture, we can easily interpret why $Y(4260)\to π^+π^-J/ψ$ has a larger rate than $Y(4260)\to D\bar D$ which has not been observed, and we also predict existence of the other two components of the isotriplet and another two possible partner states which may be observed in the future experiments. A direct consequence of this structure is that for this molecular structure $Y(4260)\to π^+π^-J/ψ$ mode is more favorable than $Y(4260)\to K\bar KJ/ψ$ which may have a larger fraction if other proposed structures prevail.

hep-ph↗

arXiv2005

Mixing of Pentaquark and Molecular States

There are experimental evidences for the existence of narrow states $Θ^+$ and $Θ_c$ with the same quantum numbers of $uudd\bar s$ and $uudd\bar c$ pentaquarks and also $NK^{(*)}$ and $ND^{(*)}$ molecular states. Their masses deviate from many theoretical estimates of the pure pentaquark and molecular states. In this work we study the possibility that the observed $Θ^+$ and $Θ_c$ are mixtures of pure pentaquark and molecular states. The mixing parameters are in general related to non-perturbative QCD which are not calculable at present. We determine them by fitting data from known states and then generalize the mechanism to $Θ_b$ to predict its mass and width. The mixing mechanism can also naturally explain the narrow width for $Θ^+$ and $Θ_c$ through destructive interferences, even if the pure pentaquark and molecular states have much larger decay widths. We also briefly discuss the properties of the partner eigenstates of $Θ^+$ and $Θ_c$ and the possibility of experimentally observe them. Moreover, probable consequences of multi-state mixing are also addressed.

hep-ph↗

arXiv2004

Can the observed enhancement in the mass spectrum of p \bar p in J/ψ\to γp \bar p be interpreted by a possible p \bar p bound state

Provided the enhancement in the $p \bar{p}$ spectrum in radiative decay $J/ψ\to γp \bar{p}$ observed by the BES collaboration is due to an existence of a $p \bar{p}$ molecular state, we calculate its binding energy and lifetime in the linear $σ$ model. We consider a possibility that the enhancement is due to a $p \bar p$ resonance which is in either S-wave or P-wave structure and compare our results with the data.

hep-ph↗

arXiv2004

Estimating Mass of Sigma-Meson and Study on Application of the Linear Sigma-Model

Whether the $σ-meson$ ($f_0(600)$) exists as a real particle is a long-standing problem in both particle physics and nuclear physics. In this work, we analyze the deuteron binding energy in the linear $σ$ model and by fitting the data, we are able to determine the range of $m_σ$ and also investigate applicability of the linear $σ$ model for the interaction between hadrons in the energy region of MeV's. Our result shows that the best fit to the data of the deuteron binding energy and other experimental data about deuteron advocates a narrow range for the $σ-$meson mass as $520\leq m_σ\leq 580$ MeV and the concrete values depend on the input parameters such as the couplings. Inversely fitting the experimental data, our results set constraints on the couplings. The other relevant phenomenological parameters in the model are simultaneously obtained.

hep-ph↗

arXiv2003

Q factor in numerical simulations of DPSK with optical delay demodulation

A simple model is used to estimate the Q factor in numerical simulations of differential phase shift keying (DPSK) with optical delay demodulation and balanced detection. It is found that an alternative definition of Q is needed for DPSK in order to have a more accurate prediction of the bit error ratio (BER).

physics.optics↗

arXiv2000

Are CSO host-galaxies undergoing merging?

The galaxy-type CSO (compact symmetric objects) rate from an intermediate large sample PR+CJ1 is found to be consistent with the Sb-Sb merger rate of 4.6% in redshift z<1. The CSO detection rate seems going down when the sample size is increasing, which could not reach the high merger rate in z>1, yet no deep VLBI sample in z>1 is available now.

astro-ph↗