arXiv subjects

Jing Song

Publications and source records attributed to Jing Song.

At least 37 records · Page 2Linked to original sources

arXiv2025

Superconductivity in trilayer nickelate La4Ni3O10 under pressure

Nickelate superconductors have attracted a great deal of attention over the past few decades due to their similar crystal and electronic structures with high-temperature cuprate superconductors. Here, we report the superconductivity in a pressurized Ruddlesden-Popper phase single crystal, La4Ni3O10 (n = 3), and its interplay with the density wave order in the phase diagram. With increasing pressure, the density wave order as indicated by the anomaly in the resistivity is progressively suppressed, followed by the emergence of the superconductivity around 25 K under I4/mmm space group. The susceptibility measurements confirm bulk superconductivity with a volume fraction exceeding 80%. Moreover, theoretical analysis unveils that antiferromagnetic (AFM) super-exchange interactions can serve as the effective pairing interaction for the emergence of superconductivity (SC) in pressurized La4Ni3O10. Our research provides a new platform for the investigation of the unconventional superconductivity mechanism in Ruddlesden-Popper trilayer perovskite nickelates.

cond-mat.supr-con↗

arXiv2025

Determination of the $K^+\bar{K}^0$ scattering length and effective range from the $D^+\to\bar{K}^0π^+η$ reaction

We study the scattering parameters of the $K^+\bar{K}^0$ system through the analysis of the $D^+\to\bar{K}^0π^+η$ reaction, aiming at determining the scattering length $a$ and effective range $r_0$ of the $K^+\bar{K}^0$ interaction. These parameters are extracted by analyzing and fitting the mass distributions of the pairs in the final $\bar{K}^0π^+η$ state. To ensure the reliability of the results, we apply resampling techniques to evaluate statistical uncertainties and improve the precision of the scattering parameters. The obtained results are compared with previous theoretical predictions and experimental data, providing new insights into the $K^+\bar{K}^0$ interaction at low energies.

hep-ph↗

arXiv2025

Pressure Tuning of Layer-hybridized Excitons in Trilayer WSe2

We demonstrate dynamic pressure tuning (0-6.6 GPa) of layer-hybridized excitons in AB-stacked trilayer WSe$_2$ via diamond-anvil-cell-integrated reflectance spectroscopy. Pressure-controlled interlayer coupling manifests in enhanced energy-level anti-crossings and oscillator strength redistribution, with Stark shift analysis revealing a characteristic dipole moment reduction of 11%. Notably, the hybridization strength between the intra- and interlayer excitons triples from $\sim$10 meV to above $\sim$30 meV, exhibiting a near-linear scaling of 3.5$\pm$0.2 meV/GPa. Spectral density simulations resolve four distinct components, i.e., intralayer ground/excited and interlayer ground/excited excitons, with their relative weights transitioning from one component dominant to strongly hybridized at higher pressures. Our findings highlight the potential for controlling excitonic properties and engineering novel optoelectronic devices through interlayer compression.

cond-mat.mtrl-sci↗

arXiv2025

Searching for the $2^+$ partner of the $T_{cs0}(2870)$ in the $B^- \to D^- D^0 K^0_S$ reaction

We study the $B^- \to D^- D^0 K^0_S$ reaction, recently analyzed by the LHCb collaboration, where a clear signal for the exotic $T_{cs0}(2870)$ state has been reported. We call the attention to a small peak in the $D^0 K^0_S$ mass distribution that could correspond to a state of the same nature as the $T_{cs0}(2870)$ ($D^* \bar K^*$ nature in the molecular picture) but with $J^P= 2^+$. In order to magnify the signal for the state, we calculate the moments of the angle-mass distribution, which are linear in the resonance signal, rather than quadratic for the angle integrated mass distribution. We find spectra for the moments with a strength far bigger than that for the angle integrated mass distribution, which should encourage the evaluation of these moments from the present measurements of the reaction.

hep-ph↗

arXiv2025

Role of $a_0( 1710)$ in the $D_s^+\toρ^+ϕ,~~ρ^+ω$ decays

We look into the $D_s^+ \to ρ^+ ϕ$ and $D_s^+ \to ρ^+ ω$ weak decays recently measured by the BESIII collaboration, which proceed very differently in a first step of the weak decay. While the first reaction proceeds directly via external emission, the second one does not go via external nor internal emission, what prompted the experimental team to claim that it proceeds via $W-$annihilation. We show in this work that the unexpectedly large rate of the $D_s^+ \to ρ^+ ω$, should it be due to $W-$annihilation, has a different explanation since is it naturally obtained once final state interaction of the $ρ^+ ϕ, ~ρ^+ ω$ and $K^{*+} \bar{K}^{*0}$ channels is taken into consideration. The interaction of these channels produces the $a_0(1710)$ resonance, predicted long ago as a molecular state of these coupled channels, and only recently observed, and it is the presence of this resonance what makes the effect of the final state interaction very important in the weak decays and provides a natural explanation of the experimental decay rates.

hep-ph↗

arXiv2024

Testing the molecular nature of the $Ω(2012)$ with the $ψ(3770) \to \barΩ \bar{K} Ξ$ and $ψ(3770) \to \barΩ \bar{K} Ξ^*(1530) (\bar Ω\bar K πΞ)$ reactions

We report on the reactions $ψ(3770)\to \barΩ^+ \bar{K} Ξ$ and $ψ(3770)\to \barΩ^+ \bar{K}Ξ^*(1530)~(Ξ^*(1530)\to πΞ$), and calculate the mass distributions $\frac{{\rm d}Γ}{{\rm d}M_\text{inv}(\bar{K}Ξ)}$ and $\frac{{\rm d}Γ}{{\rm d}M_\text{inv}(\bar{K}Ξ^*)}$, respectively. We obtain clear peaks corresponding to the $Ω(2012)$. From the decay of $ψ(3770)\to \barΩ^+ \bar{K}Ξ^*$, we also get a second, broader, peak around $2035\,\rm MeV$, which comes from the $Ω(2012)$ decay to $\bar{K}Ξ^*$. This second peak is closely tied to the molecular picture of the $Ω(2012)$ with the $\bar{K}Ξ^*(1530)$ and $ηΩ$ components. Its observation would provide a boost to the molecular picture of the $Ω(2012)$.

hep-ph↗

arXiv2024

$P_c(4440)$ and $P_c(4457)$ decay into $\bar{D}Σ_c$ and $\bar{D}Λ_c$ and the spin of the $P_c$ states

We address the issue of the width and spin assignment of the $P_c(4440)$ and $P_c(4457)$ pentaquark states. We calculate the partial decays widths of the particles into $J/ψN$, $\bar{D} Σ_c$ and $\bar{D} Λ_c$ with the first one obtained within a unitary approach with the coupled channels of $J/ψN$ and $\bar{D}^* Σ_c$ with the interaction driven by vector meson exchange, and the last two by means of triangle diagrams involving pion exchange which break the spin degeneracy of the vector meson exchange. The widths obtained depend much on the spin of the particles and we study the possible scenarios for spin assignment, favoring the $1/2^-$ , $3/2^-$ order. We predict values for decays in different channels and show that their determination would allow to decide unambiguously the spin of the states.

hep-ph↗

arXiv2024

Searching for signals of an exotic $I=1,J^P=2^+$ state of $D^K^$ nature and the structure of the $P_c(4312)$ in the $Λ_b\to Σ_c^{++} D^- K^-$ reaction

This paper investigates the decay process $Λ_b \to Σ_c^{++} D^- K^-$ with the objective of finding a predicted molecular state with isospin $I=1$, $J^P=2^+$ of $D^* K^*$ nature, plus finding support for the $P_c(4312)$ state as made out of $Σ_c \bar{D}$. The mass distribution of the $D^- K^-$ system shows distinct features as a consequence of the existing of this $2^+$ state, while the $Σ_c \bar{D}$ distribution exhibits a significant peak near the threshold, much bigger than phase space expectations, which is linked to our assumed $Σ_c \bar{D}$ nature of the $P_c(4312)$ state below the $Σ_c \bar{D}$ threshold. The reaction has been measured at LHCb Collaboration, but only the branching ratio is measured. The present study shows that much valuable information can be obtained about the predicted $2^+$ $T_{c\bar{s}}(2834)$ of $D^* K^*$ nature and the $P_c(4312)$ states from the measurements of the mass distributions in this reaction, which will be accessible in the planned updates of LHCb.

hep-ph↗

arXiv2024

Photoproduction of the $ Λ(1800) $

We have carried out a study of the $γ~ p \rightarrow p K^{+} K^{*-} (K^{*-} \rightarrow K^{-} π^{0}) $, $ γ~p \rightarrow p K^{+} K^{*-} ( K^{*-} \rightarrow \bar{K}^{0} π^{-} )$ and $ γ~p \rightarrow K^{+} K^{-}p$ reactions, producing the $K^+ Λ(1800)$ final state, from the perspective that the $Λ(1800)$ resonance is dynamically generated from the interaction of $\bar{K}^* N$ with its coupled vector-baryon channels, in complete analogy to the $Λ(1405)$ generated from the interaction of $\bar{K} N$ and its coupled pseudoscalar-baryon channels. The two reactions are complementary and their mass distributions are tied to the particular nature of this resonance in that framework. We provide much information on the shapes and strength of the invariant mass distributions of these reactions, and the energy dependence of the cross sections, that when contrasted with future experiments should shed valuable light on the nature of this resonance and its analogy to the $Λ(1405)$.

hep-ph↗

arXiv2024

Pentaquark molecular states with hidden bottom and double strangeness

We investigate the meson-baryon interaction in coupled channels with the quantum numbers of the pentaquarks $P_{bss}$ and $P_{bsss}$. The interaction is derived from an extension of the local hidden gauge approach to the heavy quark sector, which has demonstrated accurate results compared to experiments involving $Ω_{b}$, $Ξ_{b}$ states, and pentaquarks $P_{c}$ and $P_{cs}$. In our study, we identify several molecular states with small decay widths within the chosen set of coupled channels. The spin-parity ($J^P$) of these states is as follows: $J^P={\frac{1}{2}}^-$ for pseudoscalar-baryon (${\frac{1}{2}}^+$) coupled channels, $J^P={\frac{3}{2}}^-$ for pseudoscalar-baryon (${\frac{3}{2}}^+$) coupled channels, $J^P={\frac{1}{2}}^-$ and ${\frac{3}{2}}^-$ for vector-baryon (${\frac{1}{2}}^+$) coupled channels, and $J^P={\frac{1}{2}}^-$, ${\frac{3}{2}}^-$, ${\frac{5}{2}}^-$ for vector-baryon (${\frac{3}{2}}^+$) coupled channels. We search for the poles of these states and evaluate their couplings to the different channels.

hep-ph↗

arXiv2024

Study of possible $DND^*$ bound states

We start from a recently favored picture in which the $Λ_c(2940)$ and $Λ_c(2910)$ correspond mostly to $ND^*$ bound states with $J^P = 1/2^-,\, 3/2^-$ and then add a $D$ as a third particle, looking for the possible binding of the $DND^*$ three body system within the framework of the Fixed Center Approximation. We find that the system is bound with respect to the corresponding $Λ_c^* D$ threshold with a binding of about $60$ MeV and a width of about $90$ MeV. Alternatively we assume a cluster of $ND$ and a $D^*$ meson interacting with the cluster and we find similar results. The observation of these states of $J^P = 1/2^+,\, 3/2^+$ would provide new and valuable information concerning the $DN$ and $D^* N$ interaction, an issue of current debate.

hep-ph↗

arXiv2024

Searching for the two poles of the $Ξ(1820)$ in the $ψ(3686) \to \barΞ^+ \bar{K}^0 Σ^{*-}(π^- Λ)$ decay

We propose the reaction $ψ(3686) \to \barΞ^+ \bar{K}^0 Σ^{*-}$, with the $Σ^{*-}$ decaying to $π^- Λ$ in order to show evidence for the existence of two $Ξ(1820)$ states, one around $1824$ MeV and narrow, and another one around $1875$ MeV and wide. The phase space for $\bar{K}^0 Σ^{*-}$ production reduces the effect of the lower mass resonance, magnifying the effect of the higher mass resonance that shows clearly over the phase space. The estimated rate of the production is bigger than the one of the $ψ(3686) \to \barΞ^+ K^- Λ$ reaction, where a clear peak for $Ξ(1820)$ was observed by the BESIII collaboration, what makes the Beijing facility ideal to carry out the reaction proposed.

hep-ph↗

arXiv2024

A note on the tensor and vector exchange contributions to $K \bar K \to K \bar K, D \bar D \to D \bar D $ and $π^+ π^-\to π^+ π^-$ reactions

In this note we study the tensor and vector exchange contributions to the elastic reactions involving the pseudoscalars mesons $π^+ π^-$, $K^{+}K^{-}$ and $D^{+}D^{-}$. In the case of the tensor-exchange contributions we assume that an intermediate tensor $f_2(1270)$ is dynamically generated from the interaction of two virtual $ρ$ mesons, with the use of a pole approximation. The calculation of the two-loop amplitude is facilitated since the triangle loops can be factorized and computed separately. The results show very small contributions coming from the tensor-exchange mechanisms when compared with those from the vector-exchange processes. We compare our results for $ππ$ and $K\bar{K}$ scattering with those obtained in other works where the $f_2(1270)$ is considered as an ordinary $q\bar{q}$ meson. Our picture provides a smaller contribution but of similar order of magnitude for pion scattering and stabilizes the results in the case of $K\bar{K}$, allowing us to make estimates for $D\bar{D}$ scattering.

hep-ph↗

arXiv2024

Contrasting observables related to the $N^*(1535)$ from the molecular or a genuine structure

In this work we compare the predictions for the scattering length and effective range of the channels $K^0 Σ^+, K^+ Σ^0 , K^+ Λ$ and $ηp$, assuming the $N^*(1535)$ state as a molecular state of these channels, or an original genuine state, made for instance from three quarks. Looking at very different scenarios, what we conclude is that the predictions of these two pictures are drastically different, to the point that we advise the measurement of these magnitudes, accessible for instance by measuring correlation functions, in order to gain much valuable information concerning the nature of this state.

hep-ph↗

arXiv2023

Evolution of compact states to molecular ones with coupled channels: The case of the $X(3872)$

We study the molecular probability of the $X(3872)$ in the $D^0 \bar D^{*0}$ and $D^+ D^{*-}$ channels in several scenarios. One of them assumes that the state is purely due to a genuine nonmolecular component. However, it gets unavoidably dressed by the meson components to the point that in the limit of zero binding of the $D^0 \bar D^{*0}$ component becomes purely molecular. Yet, the small but finite binding allows for a nonmolecular state when the bare mass of the genuine state approaches the $D^0 \bar D^{*0}$ threshold, but, in this case the system develops a small scattering length and a huge effective range for this channel in flagrant disagreement with present values of these magnitudes. Next we discuss the possibility to have hybrid states stemming from the combined effect of a genuine state and a reasonable direct interaction between the meson components, where we find cases in which the scattering length and effective range are still compatible with data, but even then the molecular probability is as big as $95 \%$. Finally, we perform the calculations when the binding stems purely from the direct interaction between the meson-meson components. In summary we conclude, that while present data definitely rule out the possibility of a dominant nonmolecular component, the precise value of the molecular probability requires a more precise determination of the scattering length and effective range of the $D^0 \bar D^{*0}$ channel, as well as the measurement of these magnitudes for the $D^+ D^{*-}$ channel which have not been determined experimentally so far.

hep-ph↗

arXiv2023

$B^+$ decay to $K^+ηη$ with ($ηη$) from the $D\bar{D}(3720)$ bound state

We search for a $B$ decay mode where one can find a peak for a $D \bar{D}$ bound state predicted in effective theories and in Lattice QCD calculations, which has also been claimed from some reactions that show an accumulated strength in $D \bar{D}$ production at threshold. We find a good candidate in the $B^+\to K^+ ηη$ reaction, by looking at the $ηη$ mass distribution. The reaction proceeds via a first step in which one has the $B^+\to D_s^{*+} \bar{D}^0$ reaction followed by $D_s^{*+}$ decay to $D^0 K^+$ and a posterior fusion of $D^0 \bar{D}^0$ to $ηη$, implemented trough a triangle diagram that allows the $D^0 \bar{D}^0$ to be virtual and produce the bound state. The choice of $ηη$ to see the peak is based on results of calculations that find the $ηη$ among the light pseudoscalar channels with stronger coupling to the $D \bar{D}$ bound state. We find a neat peak around the predicted mass of that state in the $ηη$ mass distribution, with an integrated branching ratio for $B^+\to K^+$ ($D\bar{D}$, bound) ; ($D\bar{D}$, bound) $\to ηη$ of the order of $1.5 \times 10^{-4}$, a large number for hadronic $B$ decays, which should motivate its experimental search.

hep-ph↗

arXiv2023

Discovery of the high-entropy carbide ceramic topological superconductor candidate (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C

High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Material design and property tailoring possibilities emerge from this new class of materials. Here, we report the discovery of superconductivity around 2.35 K and topological properties in the (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C high-entropy carbide ceramic (HECC), which has not been observed before in any of the investigated HECC. Density functional theory calculations showed that six type-II Dirac points exist in (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C, which mainly contributed from the t2g orbitals of transition metals and the p orbitals of C. Due to the stability of the structure, we also observed robust superconductivity under pressure in this HEC superconductor. This study expands the physical properties of HECs, which may become a new material platform for superconductivity research, especially for studying the coupling between superconductivity and topological physics.

cond-mat.supr-con↗

arXiv2022

Molecular $Ω_{cc}$ , $Ω_{bb}$ and $Ω_{bc}$ states

We study the interaction of meson-baryon coupled channels carrying quantum numbers of $Ω_{cc}$ , $Ω_{bb}$ and $Ω_{bc}$ presently under investigation by the LHCb collaboration. The interaction is obtained from an extension of the local hidden gauge approach to the heavy quark sector that has proved to provide accurate results compared to experiment in the case of $Ω_{c}$ , $Ξ_{c}$ states and pentaquarks, $P_c$ and $P_{cs}$. We obtain many bound states, with small decay widths within the space of the chosen coupled channels. The spin-parity of the states are $J^P={\frac{1}{2}}^-$ for coupled channels of pseudoscalar-baryon (${\frac{1}{2}}^+$), $J^P={\frac{3}{2}}^-$ for the case of pseudoscalar-baryon (${\frac{3}{2}}^+$), $J^P={\frac{1}{2}}^-,{\frac{3}{2}}^-$ for the case of vector-baryon (${\frac{1}{2}}^+$) and $J^P={\frac{1}{2}}^-,{\frac{3}{2}}^-,{\frac{5}{2}}^-$ for the vector-baryon (${\frac{3}{2}}^+$) channels. We look for poles of the states and evaluate the couplings to the different channels. The couplings obtained for the open channels can serve as a guide to see in which reaction the obtained states are more likely to be observed.

hep-ph↗