In this article, we construct the six-quark currents with the $J^P=0^+$, $0^-$, $1^+$ and $1^-$ to study the $Λ_c$$Λ_c$ dibaryon and $Λ_c$$\barΛ_c$ baryonium states via QCD sum rules. We consider the vacuum condensates up to dimension 16 and truncation of the order $\mathcal{O}(α_s^k )$ with $k\leq3$. The predicted masses are $5.11_{-0.12}^{+0.15}$GeV, $4.66_{-0.06}^{+0.10}$GeV, $4.99_{-0.09}^{+0.10}$GeV $4.68^{+0.08}_{-0.08}$GeV for the $J^P=0^+$, $0^-$, $1^+$ and $1^-$ states, respectively, which can be confronted to the experimental data in the future considering the high integrated luminosity at the center-of-mass energy about $4.8\,\rm{GeV}$ at the BESIII. We find the terms with $\frac{3}{2}< k \leq 3$ do play a tiny role, and we can ignore these terms safely in the QCD sum rules.
In the present work, we construct eight six-quark currents to study the $Σ_c\barΣ_c$ baryonium and $Σ_cΣ_c$ dibaryon states via the QCD sum rules. For either $Σ_c\barΣ_c$ baryonium or $Σ_cΣ_c$ dibaryon states, we construct four currents with the $J^P=1^-, 1^+, 0^+$ and $0^-$. Except the current $1^+$ of $Σ_cΣ_c$, we find the Borel windows for the other seven. There are two possible $Σ_c\barΣ_c$ molecular states or compact six-quark states with the $J^P=1^-$ and $0^-$. The results of the current $0^+$ of $Σ_cΣ_c$ show a possible $Σ_cΣ_c$ molecular state with $20$ MeV binding energy. We find two…
We evaluate the light baryonium spectrum, viz. the baryon-antibaryon states, in the framework of QCD sum rules. The nonperturbative contributions up to dimension 12 are taken into account. Numerical results indicate that there might exist eight possible light baryonium states, i.e. $p$-$\bar{p}$, $Λ$-$\barΛ$, $Σ$-$\barΣ$, and $Ξ$-$\barΞ$ with quantum numbers of $0^{-+}$ and $1^{--}$. For the $Λ$-$\barΛ$, $Σ$-$\barΣ$, and $Ξ$-$\barΞ$ states, their masses are found above the corresponding dibaryon thresholds, while the masses of $p$-$\bar{p}$ states are not. The possible baryonium decay modes ar…
In this work, we investigate the spectra of the prospective tetracharm and tetrabottom baryonium, viz. the baryon-antibaryon states, in the framework of QCD sum rules. The non-perturbative contributions up to dimension 10 are taken into account. Numerical results indicate that there might exist 4 possible tetracharm baryonium states with masses $(7.33\pm0.12)$, $(7.42\pm0.13)$, $(7.68\pm0.17)$, and $(7.76\pm0.12)$ GeV for the quantum numbers of $0^{-+}$, $1^{--}$, $0^{++}$, and $1^{++}$, respectively. The corresponding tetrabottom partners are found lying respectively at $(19.41\pm 0.15)$, $(1…
In this paper, we investigate the spectra of the prospective hidden-bottom and -charm hexaquark states with quantum numbers $J^{PC }= 0^{++}$, $0^{-+}$, $1^{++}$ and $1^{--}$ in the framework of QCD sum rules. By constructing appropriate interpreting currents, the QCD sum rules analyses are performed up to dimension 12 of the condensates. Results indicate that there exist two possible baryonium states in $b$-quark sector with masses $11.84 \pm 0.22$ GeV and $11.72 \pm 0.26$ GeV for $0^{++}$ and $1^{--}$, respectively. The corresponding hidden-charm partners are found lying respectively at $5.1…
Searching for hidden-charm baryonium signals in QCD sum rules
本文对夸克含量为$u\bar u d\bar d c\bar c$、自旋为$J=0/1/2/3$、宇称为正宇称和负宇称的隐魅重子态进行了QCD求和规则研究。我们系统地构造了相应的局域隐魅重子素内插流，它可以耦合到各种结构，包括隐魅重子素态、隐魅重子素态加两个π介子、隐魅四夸克态加一个π介子等。我们起初不知道这些流耦合到哪种结构，但通过求和规则分析，我们可以得到一些信息。我们发现它们中的一些可以耦合到隐魅重子态，并由此估算了最低能级的隐魅重子态的质量，其量子数为$J^P=2^-/3^-/0^+/1^+/2^+$，约为5.0 GeV.我们建议在这个能区的$D$波$J/ψππ$和$P$波$J/ψρ$和$J/ψω$通道中寻找重子的隐魅态，特别是$J=3^-$的隐魅态.
In order to confirm the existence of the dibaryon state $d^*(2380)$ observed at WASA@COSY, we estimate the production of the possible dibaryon and anti-dibaryon pair $d^*\bar{d}^*$ at the energy region of the upcoming experiments at $\bar{\rm{P}}$anda. Based on some qualitative properties of $d^*$ extracted from the analysez in the non-relativistic quark model, the production cross section for this spin-3 particle pair are calculated with the help of an phenomenological effective relativistic and covariant Lagrangian approach.
10 and 27 SU(3) multiplets of hexaquarks states with baryon number B=2, known as dibaryons, are considered. Previous analyses are complemented and sum rules for strong decay amplitudes with SU(3) symmetry violation up to the first order are determined for the 10 and 27 dibaryon multiplets into a baryon octet plus a baryon decuplet and for the dibaryon 27 into two baryon octets.
In this article, we construct the color-singlet-color-singlet type currents to study the scalar and axialvector $Ξ_{cc}Σ_c$ dibaryon states with QCD sum rules in details by taking into account both the dibaryon states and two-baryon scattering sates at the hadron side, and examine the existence of the $Ξ_{cc}Σ_c$ dibaryon states. Our calculations indicate that the two-baryon scattering states cannot saturate the QCD sum rules, it is necessary to introduce the dibaryon states, the color-singlet-color-singlet type currents couple potentially to the molecular states, not to the two-particle scatt…
In this work, we systematically investigate the dibaryons with charm number $C$=1 and strangeness number $S$=$\pm$ 1 from the interactions of a charmed baryon and a strange baryon $Λ_cΛ$, $Λ_cΣ^{(*)}$, $Σ_c^{(*)}Λ$, and $Σ^{(*)}_cΣ^{(*)}$, and corresponding interactions of a charmed baryon and an antistrange baryon $Λ_c\barΛ$, $Λ_c\barΣ^{(*)}$, $Σ^{(*)}_c\barΛ$, and $Σ^{(*)}_c\barΣ^{(*)}$. With the help of the effective Lagrangians with $SU(3)$, heavy quark, and chiral symmetries, the potentials of the interactions considered are constructed by light meson exchanges. To search for the possible…
We study breakup of the deuteron induced by neutrinos in the neutral $νd\to νnp$, $\barν d\to \barν np$ and the charged $\barν d\to e^+ n n$, $νd\to e^- pp$ processes. Pionless effective field theory with dibaryon fields is used to calculate the total cross sections for neutrino energies $E_ν$ from threshold to 20 MeV. Amplitudes are expanded up to next-to-leading order, and the partial wave is truncated at $P$-waves. The Coulomb interaction between two protons is included nonperturbatively in the reaction amplitudes, and an analytic expression of the amplitudes is obtained. The contribution o…
We study the multiquark hadrons in large $N$ QCD under the 't-Hooft limit, extending Witten's picture of the baryons. We explore the decay widths of tetraquarks, pentaquarks and dibaryons. Based on the decay behaviors, we point out in the $N\to \infty$ limit decay widths of tetraquarks stay constant, while those of pentaquarks and dibaryons above certain thresholds can diverge. In the large $N$ limit, we find that the ground states of the three spectroscopic series are stable or narrow and that the excited states of pentaquarks and dibaryons above the indicated thresholds are not observables. …
The pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4450)$, can be nicely arranged into a multiplet of seven molecules of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ dictated by heavy quark spin symmetry, while the $Ξ_{cc}^{(\ast)}Σ_{c}^{(\ast)}$ system can be related to the $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ system via heavy antiquark diquark symmetry. In this work we employ the one boson exchange model to study the interactions between $Ξ_{cc}^{(\ast)}$ and $Σ_{c}^{(\ast)}$ with constraints from the pentaquark system. We show that a multiplet of ten triply charmed dibaryons emerge naturally in…
We present a lattice QCD spectroscopy study in the isospin singlet, strangeness $-2$ sectors relevant for the conjectured $H$ dibaryon. We employ both local and bilocal interpolating operators to isolate the ground state in the rest frame and in moving frames. Calculations are performed using two flavors of O($a$)-improved Wilson fermions and a quenched strange quark. Our initial point-source method for constructing correlators does not allow for bilocal operators at the source; nevertheless, results from using these operators at the sink indicate that they provide an improved overlap onto the…
We report the first lattice quantum chromodynamics (QCD) study of deuteron($np$)-like dibaryons with heavy quark flavours. These include particles with following dibaryon structures and valence quark contents: $Σ_cΞ_{cc} (uucucc)$, $Ω_cΩ_{cc} (sscscc)$, $Σ_bΞ_{bb} (uububb)$, $Ω_bΩ_{bb} (ssbsbb)$ and $Ω_{ccb}Ω_{cbb} (ccbcbb)$, and with spin ($J$)-parity ($P$), $J^{P} \equiv 1^{+}$. Using a state-of-the art lattice QCD calculation, after controlling relevant systematic errors, we unambiguously find that the ground state masses of dibaryons $Ω_cΩ_{cc} (sscscc)$, $Ω_bΩ_{bb} (ssbsbb)$ and $Ω_{ccb}Ω…
The LHCb collaboration has recently observed three narrow pentaquark states --- the $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ ---that are located close to the $\bar{D} Σ_c$ and $\bar{D}^* Σ_c$ thresholds. Among the so-far proposed theoretical interpretations for these pentaquarks, the molecular hypothesis seems to be the preferred one. Nevertheless, in the molecular picture the spins of the $P_c(4440)$ and $P_c(4457)$ have not been unambiguously determined yet. In this letter we point out that heavy antiquark-diquark symmetry induces a model-independent relation between the spin-splitting in t…
We present the first study of baryon-baryon interactions in the continuum limit of lattice QCD, finding unexpectedly large lattice artifacts. Specifically, we determine the binding energy of the $H$ dibaryon at a single quark-mass point. The calculation is performed at six values of the lattice spacing $a$, using O($a$)-improved Wilson fermions at the SU(3)-symmetric point with $m_π=m_K\approx 420$ MeV. Energy levels are extracted by applying a variational method to correlation matrices of bilocal two-baryon interpolating operators computed using the distillation technique. Our analysis employ…
A pair of triply charmed baryons, $Ω_{ccc}Ω_{ccc}$, is studied as an ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical light-quark masses and the relativistic heavy quark action with the physical charm quark mass. The spatial baryon-baryon correlation is related to their scattering parameters on the basis of the HAL QCD method. The $Ω_{ccc}Ω_{ccc}$ in the ${^1S_0}$ channel taking into account the Coulomb repulsion with the charge form factor of $Ω_{ccc}$ leads to the scattering length $a^{\rm C}_0\simeq -19~\text{fm}$ and the effective range $r^{\rm C}_{\mathrm{eff}}\simeq…
We present a first study on a pair of triply charmed baryons, $Ω_{ccc}Ω_{ccc}$ in the $^1S_0$ channel, on the basis of the HAL QCD method. The measurements are perfomed on the $(2+1)$-flavor lattice QCD configurations with nearly physical light-quark masses and physical charm-quark mass. We show that the system with the Coulomb repulsion taking into account the charge form factor of $Ω_{ccc}$ leads to the scattering length $a^\mathrm{C}_0\simeq-19$ fm and the effective range $r^\mathrm{C}_\mathrm{eff}\simeq0.45$ fm, which indicates $Ω_{ccc}Ω_{ccc}$ is located in the unitary regime.
