arXiv subjects

Bao-Xi Sun

Publications and source records attributed to Bao-Xi Sun.

At least 19 recordsLinked to original sources

arXiv2025

Possible $K \bar{K}^$ and $D \bar{D}^$ resonances by solving Schr\"odinger equation

The one-pion exchange interaction between the kaon and the vector antikaon is investigated by solving the Schr\"odinger equation in the S-wave approximation. In addition to the particle $f_1(1285)$, another bound state of $K \bar{K}^*$ is obtained, which is approximately 9 MeV below the threshold of $K \bar{K}^*$ and labeled $f_1(1378)$ for convenience in this manuscript. Under the outgoing wave condition, two resonance states of $K \bar{K}^*$ are produced with different coupling constants fixed with the binding energies of $f_1(1285)$ and $f_1(1378)$, respectively. Both of the resonance states are located in the vicinity of 1400 MeV, and thus it is reasonable to assume that these two resonance states correspond to the $f_1(1420)$ particle in the review of the Particle Data Group simultaneously. This method is extended to study the $D \bar{D}^*$ system analogously. When the particle $\chi_{c1}(3872)$ is treated as a bound state of $D \bar{D}^*$, the particles $T_{c\bar{c}1}(3900)$, $T_{c \bar{c}}(4020)$ and $X(3940)$ can be obtained as solutions of the Schr\"odinger equation under the outgoing wave condition, which implies the spin and parity of these particles are all $J^P=1^+$.

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arXiv2025

The $\phi p$ bound state in the unitary coupled-channel approximation

The attractive interaction of the $\phi$ meson and the proton is reported by the ALICE Collaboration, and the corresponding scattering length $f_0$ is given as $Re(f_0)=0.85\pm0.34(stat)\pm0.14(syst)$ fm and $Im(f_0)=0.16\pm0.10(stat)\pm0.09(syst)$ fm. The fact that the real part is significant in contrast to the imaginary part indicates a dominating role of the elastic scattering, whereas the inelastic process is less important. In this work, such scattering processes are inspected on the basis of a unitary coupled-channel approximation inspired by the Bethe-Salpeter equation. The $\phi p$ scattering length is calculated and it is found that the experimental value of the $\phi p$ scattering length can be obtained only if the attractive interaction of the $\phi$ meson and the proton is taken into account. A significant outcome of such an attractive interaction is a two-pole structure in the scattering amplitude. One of the poles, located at $1969-i283$ MeV, might be a resonance state of $\phi N$, while the other pole, located at $1949-i3$ MeV, should be a bound state of $\phi N$. Both of these states do not have counterparts in the data of the Particle Data Group(PDG).

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arXiv2025

Study on Pentaqaurks by Solving Schrodinger Equation in the Non-Hermitian Quantum Mechanics

The interaction of the charmed baryon and the anticharmed meson is assumed to be realized by exchanging a scalar meson of $f_0(500)$, and then these systems are studied by solving the Schrodinger equation, respectively. When the pentaquarks $P_{c\bar{c}}(4312)^{+}$, $P_{c\bar{c}}(4457)^{+}$, $P_{c\bar{c}s}(4338)^0$, and $P_{c\bar{c}s}(4459)^{0}$ are treated as $Σ_c \bar{D}$, $Σ_c \bar{D}^*$, $Ξ_c \bar{D}$ and $Ξ_c \bar{D}^*$ bound states, four resonance states of them are obtained as solutions of the Schrodinger equation under the outgoing wave condition, respectively. The resonance state of $Σ_c \bar{D}$ might correspond to the particle $P_{c\bar{c}}(4440)^{+}$, while the other three resonance states have no counterparts in the review of the Particle Data Group(PDG). Although the binding energy of the bound state is only several MeVs, all these resonance states are more than 100 MeV higher than their corresponding thresholds, respectively. The calculation results indicate that the spectrums of the strange and non-strange pentaquarks are symmetric to each other.

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arXiv2025

Does $f_1(1420)$ have a double-peak structure?

The one-pion exchange interaction between the kaon and the vector antikaon is investigated by solving the Schrodinger equation in the S-wave approximation. In addition to the $f_1(1285)$ particle, another bound state of $K \bar{K}^*$ is found, which is approximately 9 MeV below the threshold of $K \bar{K}^*$ and labeled $f_1(1378)$ for convenience in this manuscript. Under the outgoing wave condition, two resonance states of $K \bar{K}^*$ are produced by solving the Schrodinger equation with different coupling constants in the one-pion-exchange potential fixed with the binding energies of $K \bar{K}^*$ bound states $f_1(1285)$ and $f_1(1378)$ respectively. Both of the resonance states are located in the vicinity of 1400 MeV, and thus it is reasonable to assume that these two resonance states correspond to the $f_1(1420)$ particle in the review of the Particle Data Group although they arise from different couplings of the kaon and vector antikaon, respectively.

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arXiv2025

The $α$ condensate states of atomic nuclei ${}^{12}C$, ${}^{16}O$ and ${}^{20}Ne$ in an analytical solvable model

The $α$ condensation in the ${}^{12}C$, ${}^{16}O$ and ${}^{20}Ne$ nuclei is investigated within an analytical solvable model. It is found that the calculated ratio of the ground state energies of the Hoyle state of ${}^{12}C$ and the Hoyle-like state of ${}^{16}O$ is consistent with that of the experimental values. Along this clue, the ground state energy of ${}^{20}Ne$ is obtained to be 1MeV approximately, which is far less than the experimental value of 3MeV. Additionally, the root-mean-square radii of these nuclei are also calculated, and all of them lies around 9fm, which is different from the result calculated with the Tohsaki-Horiuchi-Schuck-Ropke(THSR) wave function. Since the root-mean-square radius is relevant to the ground state energy of the $α$ condensate nucleus, the root-mean-square radii of ${}^{16}O$ and ${}^{20}Ne$ are also calculated with the ground state energies used in the THRS wave function. As a result, the root-mean-square radii of ${}^{16}O$ and ${}^{20}Ne$ reduced to 5fm, and it is similar to the result obtained with the THRS wave function. The calculation result manifests that the root-mean-square radius of $α$ condensate nuclei decreases with the energy increasing.

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arXiv2024

The possible $K \bar{K}^$ and $D \bar{D}^$ bound and resonance states by solving Schrodinger equation

The Schrodinger equation with a Yukawa type of potential is solved analytically. When different boundary conditions are taken into account, a series of solutions are indicated as Bessel function, the first kind of Hankel function and the second kind of Hankel function, respectively. Subsequently, the scattering processes of $K \bar{K}^*$ and $D \bar{ D}^*$ are investigated. In the $K \bar{K}^*$ sector, the $f_1(1285)$ particle is treated as a $K \bar{K}^*$ bound state, therefore, the coupling constant in the $K \bar{K}^*$ Yukawa potential can be fixed according to the binding energy of the $f_1(1285)$ particle. Consequently, a $K \bar{K}^*$ resonance state is generated by solving the Schrodinger equation with the outgoing wave condition, which lie at $1417-i18$MeV on the complex energy plane. It is reasonable to assume that the $K \bar{K}^*$ resonance state at $1417-i18$MeV might correspond to the $f_1(1420)$ particle in the review of Particle Data Group(PDG).In the $D \bar{D}^*$ sector, since the $X(3872)$ particle is almost located at the $D \bar{ D}^*$ threshold, the binding energy of it equals to zero approximately. Therefore, the coupling constant in the $D \bar{ D}^*$ Yukawa potential is determined, which is related to the first zero point of the zero order Bessel function. Similarly to the $K \bar{K}^*$ case, four resonance states are produced as solutions of the Schrodinger equation with the outgoing wave condition. It is assumed that the resonance states at $3885-i1$MeV, $4029-i108$ MeV, $4328-i191$MeV and $4772-i267$MeV might be associated with the $Zc(3900)$, the $X(3940)$, the $χ_{c1}(4274)$ and $χ_{c1}(4685)$ particles, respectively. It is noted that all solutions are isospin degenerate.

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arXiv2024

The proton-neutron resonance states by solving Schrodinger equation

The proton-neutron interaction is investigated by solving the Schrodinger equation, where a Yukawa type of potential with one pion exchanging between the proton and the neutron is assumed. Since the deutron is the unique bound state of the proton-neutron system, the coupling constant is fixed according to the binding energy of the deutron. The scattering process of the proton and the neutron is studied when the outgoing wave condition is taken into account, and two proton-neutron resonance states are obtained by solving the Schrodinger equation, which lie at $1905-i13$MeV and $2150-i342$MeV on the complex energy plane, respectively. It is no doubt that the calculation results would give some hints on the experimental research on the proton-neutron interaction in future.

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arXiv2023

The $ϕp$ bound state in the unitary coupled-channel approximation

The strong attractive interaction of the $ϕ$ meson and the proton is reported by ALICE collaboration recently. The corresponding scattering length $f_0$ is given as $Re(f_0)=0.85\pm0.34(stat)\pm0.14(syst)$fm and $Im(f_0)=0.16\pm0.10(stat)\pm0.09(syst)$fm. The fact that the real part is significant in contrast to the imaginary part indicates a dominate role of the elastic scattering, whereas the inelastic process is less important. In this work, such scattering processes are inspected based on a unitary coupled-channel approach inspired by Bethe-Salpeter equation. The $ϕp$ scattering length is calculated based on this approach, and it is found that the experimental value of the $ϕp$ scattering length can be obtained only if the attractive interaction of the $ϕ$ meson and the proton is taken into account. A significant outcome of such attractive interaction is a two-pole structure in the $ϕp$ scattering amplitude. One of the pole, locating at $(1969-i283)$~MeV might correspond to $N(1895)1/2^-$ or $N(1875)3/2^-$ listed in the review of the Particle Data Group(PDG). The other one, locating at ${1949-i3}$~MeV should be a $ϕN$ bound state, which has no counterpart in the PDG data.

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arXiv2021

The pseudoscalar meson and baryon octet interaction with strangeness $S=-2$ in the unitary coupled-channel approximation

The interaction of the pseudoscalar meson and the baryon octet is investigated by solving the Bethe-Salpeter equation in the infinite and finite volume respectively. It is found that there is a resonance state generated dynamically, which owns a mass about 1550MeV and a large decay width of 120-200MeV. This resonance state couples strongly to the $πΞ$ channel. Therefore, it might not correspond to the $Ξ(1620)$ particle announced by Belle collaboration. At the same time, this problem is studied in the finite volume, and an energy level at 1570MeV is obtained, which is between the $πΞ$ and $\bar{K}Λ$ thresholds and independent of the cubic box size.

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arXiv2020

The collective excitation of nuclear matter in a bosonized Landau Fermi liquid model

The collective excitation of nuclear matter is analyzed in a bosonized Landau Fermi liquid model. When the nonlinear self-interacting terms of scalar mesons are included in Walecka model, the collective excitation energy of nuclear matter can be obtained self-consistently, and the calculation results are consistent with the corresponding experimental data of the nucleus ${}^{208}Pb$ when the quantum number of the orientation of the total spin $m$ is zero. The cases with the nonzero $m$ values are also studied, and it is found that the collective excitation energy of nuclear matter decreases with the absolute value of $m$ increasing when the total spin is conserved. Moreover, four kinds of collective excitation modes of nuclear matter are discussed when the isospin and spin of nucleons are taken into account. The direct interaction between two nucleons near Fermi surface only changes the effective nucleon mass and Fermi velocity, while the exchange interaction plays an critical role in the collective excitation of nuclear matter.

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arXiv2019

The pseudoscalar meson and baryon octet interaction in the unitary coupled-channel approximation

The pseudoscalar meson-baryon octet interaction is studied within a nonlinear realized Lagrangian, and then the Bethe-Salpeter equation is solved in the unitary coupled-channel approximation. In sector of strangeness $S=-1$ and isospin $I=0$, only one pole is generated dynamically in the 1400MeV region, which might correspond to the $Λ(1405)$ particle. When the case of strangeness zero is studied, the $s-$ and $u-$ potentials are taken into account in the kernel, and a resonance state is produced in the 1500MeV region, which might be a counterpart of the N(1535) particle.

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arXiv2019

The pseudoscalar meson and baryon octet interaction with strangeness zero in the unitary coupled-channel approximation

The interaction of the pseudoscalar meson and the baryon octet is investigated by solving the Bethe-Salpeter equation in the unitary coupled-channel approximation, In addition to the Weinberg-Tomozawa term, the contribution of the $s-$ and $u-$ channel potentials in the S-wave approximation are taken into account. In the sector of isospin $I=1/2$ and strangeness $S=0$, a pole is detected in the reasonable region on the complex energy plane of $\sqrt{s}$ in the center of mass frame by analyzing the behavior of the scattering amplitude, which is higher than the $ηN$ threshold and lies on the third Riemann sheet. Thus it can be regarded as a resonance state and might correspond to the $N(1535)$ particle in the review of the Particle Data Group(PDG). The coupling constants of this resonance state to the $πN$, $ηN$, $K Λ$ and $K Σ$ channels are calculated, and it is found that this resonance state couples strongly to the hidden strange channels. Apparently, the hidden strange channels play an important role in the generation of the resonance state with strangeness zero. The interaction of the pseudoscalar meson and the baryon octet is repulsive in the sector of isospin $I=3/2$ and strangeness $S=0$, therefore, no resonance state can be generated dynamically.

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arXiv2018

The $K\bar{K}^*$ interaction in the unitary coupled-channel approximation

The $K\bar{K}^*$ interaction Lagrangian is constructed when the $SU(3)$ hidden gauge symmetry is taken into account, and then the $K\bar{K}^*$ potential is obtained. In the low energy region, the $K\bar{K}^*$ potential mainly comes from the contribution of the $t-$channel interaction by exchanging $ρ$,$ω$ and $φ$ mesons, respectively. The $K\bar{K}^*$ amplitude is investigated by solving the Bethe-Salpeter equation in the unitary coupled-channel approximation, where the loop function of the vector and pseudoscalar mesons are evaluated in the dimensional regularization scheme, and the contribution of the longitudinal part of the intermediate vector meson propagator is included in the calculation. Finally, it is found that a resonance state of $K\bar{K}^*$ is generated in the isospin $I=0$ sector, which might correspond to the $f_1(1420)$ particle in the review of the particle data group(PDG). Moreover, in the isospin $I=1$ sector, a pole of the $K\bar{K}^*$ amplitude is detected at $1425-i316$MeV on the complex plane of the total energy in the center of mass system, which is higher than the $K\bar{K}^*$ threshold. Thus this pole might be a resonance state of $K\bar{K}^*$ although no counterpart has been found in the PDG review.

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arXiv2018

The $D\bar{D}^*$ interaction with isospin zero in an extended hidden gauge symmetry approach

The $D \bar{D}^*$ interaction via a $ρ$ or $ω$ exchange is constructed within an extended hidden gauge symmetry approach, where the strange quark is replaced by the charm quark in the $SU(3)$ flavor space. With this $D \bar{D}^*$ interaction, a bound state slightly lower than the $D \bar{D}^*$ threshold is generated dynamically in the isospin zero sector by solving the Bethe-Salpeter equation in the coupled-channel approximation, which might correspond to the $X(3872)$ particle announced by many collaborations. This formulism is also used to study the $B \bar{B}^*$ interaction, and a $B \bar{B}^*$ bound state with isospin zero is generated dynamically, which has no counterpart listed in the review of the Particle Data Group. Furthermore, the one-pion exchange between the $D$ meson and the $\bar{D}^*$ is analyzed precisely, and we do not think the one-pion exchange potential need be considered when the Bethe-Salpeter equation is solved.

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arXiv2017

$D \bar{D}^*$ and $πψ$ interactions in a unitary coupled-channel approximation

The $D \bar{D}^*$ interaction via a $πψ$ intermediate state is studied carefully in the isospin $I=1$ sector. By solving the Bethe-Salpeter equation in the unitary coupled-channel approximation, we obtain the S-wave amplitude as a function of the total energy of the system in the center of mass frame. A resonance state is generated dynamically in the 3900MeV region, which might correspond to the $Zc(3900)$ particle. Moreover, the loop function of a vector meson and a pseudoscalar meson is deduced explicitly in the dimensional regularization scheme and the contribution of the longitudinal part of the vector meson propagator is taken into account. The initial and final polarization vectors in the vertex of the vector meson and the pseudoscalar meson are eliminated when the Bethe-Salpeter equation is solved, and it is certified that the amplitude is still unitary in the calculation.

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arXiv2017

The Lambda(1405) state in a chiral unitary approach with off-shell corrections to dimensional regularized loop functions

The Bethe-Salpeter equation is solved in the framework of unitary coupled-channel approximation by using the pseudoscalar meson-baryon octet interaction. The loop function of the intermediate meson and baryon is deduced in a dimensional regularization scheme, where the relativistic kinetic effect and off-shell corrections are taken into account. According to the experimental data at the $K^- p$ threshold, the subtraction constants in the loop function are determined. The squared amplitude is suppressed strongly and only one $Λ(1405)$ state is generated dynamically in the strangeness $S=-1$ and isospin $I=0$ sector.

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arXiv2017

Study of X(5568) in a unitary coupled-channel approximation of $B \bar{K}$ and $B_s π$

The potential of the $B$ meson and the pseudoscalar meson is constructed up to the next-to-leading order Lagrangian, and then the $B \bar{K}$ and $B_s π$ interaction is studied in the unitary coupled-channel approximation, and a resonant state with a mass about $5568MeV$ and $J^P=0^+$ is generated dynamically, which can be associated with the $X(5568)$ state announced by D0 Collaboration recently. The mass and the decay width of this resonant state depend on the regularization scale in the dimensional regularization scheme, or the maximum momentum in the momentum cutoff regularization scheme. The scattering amplitude of the vector $B$ meson and the pseudoscalar meson is calculated, and an axial-vector state with a mass near $5620MeV$ and $J^P=1^+$ is produced. Moreover, their partners in the charm sector are also discussed.

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arXiv2014

Dynamically generated resonances from the vector meson-octet baryon interaction in the strangeness zero sector

The interaction potentials between vector mesons and octet baryons are calculated explicitly with a summation of t-, s-, u-channel diagrams and a contact term originating from the tensor interaction. Many resonances are generated dynamically in different channels of strangeness zero by solving the coupled-channel Lippman-Schwinger equations with the method of partial wave analysis, and their total angular momenta are determined. The spin partners N(1650)1/2^{-} and N(1700)3/2^-, N(1895)1/2^{-} and N(1875)3/2^-, and the state N(2120)3/2^- are all produced respectively in the isospin I=1/2 sector. In the isospin I=3/2 sector, the spin partners Delta(1620)1/2^- and Delta(1700)3/2^- are also associated with the pole in the complex energy plane. According to the calculation results, a J^P=1/2^- state around 2000 MeV is predicted as the spin partner of N(2120)3/2^-. Some resonances are well fitted with their counterparts listed in the newest review of Particle Data Group(PDG), while others might stimulate the experimental observation in these energy regions in the future.

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