Search

We study strong decays of the $\phi(2170)$, along with its possible partner $X(2436)$, as two fully-strange tetraquark states of $J^{PC} = 1^{--}$. We consider seven decay channels: $\phi \eta$, $\phi \eta^\prime$, $\phi f_0(980)$, $\phi f_1(1420)$, $h_1(1415) \eta$, $h_1(1415) \eta^\prime$, and $h_1(1415) f_1(1420)$. Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios can be useful in determining the nature of the $\phi(2170)$ and $X(2436)$. The $\phi(2170)$ has been observed in the $\phi f_0(980)$, $\phi \eta$, and $\phi \eta^\prime$ channels, and we propose to further examine it in the $h_1(1415) \eta$ channel. Evidences of the $X(2436)$ have been observed in the $\phi f_0(980)$ channel, and we propose to verify whether this structure exists or not in the $\phi \eta$, $\phi \eta^\prime$, $h_1(1415) \eta$, and $h_1(1415) \eta^\prime$ channels., Comment: 10 pages, 3 figures, 1 table, suggestions and comments are welcome

We study the $\Xi_b(6100)$ using the methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. Our results suggest that the $\Xi_b(6100)$ can be well interpreted as the $P$-wave bottom baryon of $J^P=3/2^-$, belonging to the $SU(3)$ flavor $\mathbf{\bar 3}_F$ representation. It has a partner state of $J^P=1/2^-$, labelled as $\Xi_b(1/2^-)$, whose mass and width are predicted to be $m_{\Xi_b(1/2^-)}=6.08^{+0.13}_{-0.11}$~GeV and $\Gamma_{\Xi_b(1/2^-)}=4^{+29}_{-~4}$~MeV, with the mass splitting $\Delta M=m_{\Xi_b(6100)}-m_{\Xi_b(1/2^-)}=9\pm3$~MeV. We propose to search for it in the $\Xi_c({1/2}^-)\to \Xi_b^{\prime}\pi$ decay channel. Our results also suggest that the $\Lambda_b(5912)$ and $\Lambda_b(5920)$ are their partner states with $J^P=1/2^-$ and $3/2^-$ respectively, and moreover, the $\Lambda_c(2595)$, $\Lambda_c(2625)$, $\Xi_c(2790)$, and $\Xi_c(2815)$ are their charmed partner states., Comment: 13 pages, 2 figures, 4 tables, suggestions and comments welcome. arXiv admin note: text overlap with arXiv:2106.15488

We apply the method of QCD sum rules to study the $s q \bar s \bar q$ tetraquark states with the exotic quantum number $J^{PC} = 3^{-+}$, and extract mass of the lowest-lying state to be $2.33^{+0.19}_{-0.16}$ GeV. To construct the relevant tetraquark currents we need to explicitly add the covariant derivative operator. Our systematical analysis on their relevant interpolating currents indicates that: a) this state well decays into the $P$-wave $\rho\phi/\omega\phi$ channel but not into the $\rho f_2(1525)/\omega f_2(1525)/\phi f_2(1270)$ channels, and b) it well decays into the $K^*(892) \bar K_2^*(1430)$ channel but not into the $P$-wave $K^*(892) \bar K^*(892)$ channel., Comment: 9 pages, 4 figures, to be published in PRD

We apply the method of QCD sum rules to study the $s s \bar s \bar s$ tetraquark states of $J^{PC} = 0^{-+}$. We construct all the relevant $s s \bar s \bar s$ tetraquark currents, and find that there are only two independent ones. We use them to further construct two weakly-correlated mixed currents. One of them leads to reliable QCD sum rule results and the mass is extracted to be $2.51^{+0.15}_{-0.12}$ GeV, suggesting that the $X(2370)$ or the $X(2500)$ can be explained as the $ss\bar s\bar s$ tetraquark state of $J^{PC} = 0^{-+}$. To verify this interpretation, we propose to further study the $\pi\pi/K \bar K$ invariant mass spectra of the $J/\psi \to \gamma \pi \pi \eta^\prime/\gamma K \bar K \eta^\prime$ decays in BESIII to examine whether there exists the $f_0(980)$ resonance., Comment: 8 pages, 6 figures, suggestions and comments are welcome

The heavy baryon system bounded by the strong interaction has a rich internal structure, so its mass spectra can have the fine structure similar to the line spectra of atom bounded by the electromagnetic interaction. We systematically study the internal structure of $P$-wave $\Omega_b$ baryons and calculate their $D$-wave decay properties. The present study, together with our previous studies on their mass spectra and $S$-wave decay properties, suggest that all the four excited $\Omega_b$ baryons recently discovered by LHCb can be well explained as $P$-wave $\Omega_b$ baryons, and their beautiful fine structure is directly related to the rich internal structure of $P$-wave $\Omega_b$ baryons., Comment: 6 pages, 1 figure, 2 tables, published in EPJC

We use the method of light-cone sum rules to study decay properties of $P$-wave bottom baryons belonging to the $SU(3)$ flavor $\mathbf{6}_F$ representation. In Ref.~\cite{Cui:2019dzj} we have studied their mass spectrum and pionic decays, and found that the $\Sigma_{b}(6097)$ and $\Xi_{b}(6227)$ can be well interpreted as $P$-wave bottom baryons of $J^P = 3/2^-$. In this paper we further study their decays into ground-state bottom baryons and vector mesons. We propose to search for a new state $\Xi_b({5/2}^-)$, that is the $J^P = 5/2^-$ partner state of the $\Xi_{b}(6227)$, in the $\Xi_b({5/2}^-) \to \Xi_b^{*}\rho \to \Xi_b^{*}\pi\pi$ decay process. Its mass is $12 \pm 5$~MeV larger than that of the $\Xi_{b}(6227)$., Comment: 18 pages, 5 figures, 5 tables

We use the method of QCD sum rules within the framework of heavy quark effective theory to study the mass spectrum of the $\Sigma_{b}(6097)^{\pm}$ and $\Xi_{b}(6227)^{-}$, and use the method of light-cone sum rules still within the heavy quark effective theory to study their decay properties. Our results suggest that they can be well interpreted as $P$-wave bottom baryons with the spin-parity $J^P = 3/2^-$. They belong to the baryon doublet $[\mathbf{6}_F, 2, 1, \lambda]$, where the total and spin angular momenta of the light degree of freedom are $j_l = 2$ and $s_l = 1$, and the orbital angular momentum is between the bottom quark and the two-light-quark system ($\lambda$-type). This doublet contains six bottom baryons, and we predict masses (mass differences) and decay widths of the other four states to be $M_{\Omega_b(3/2^-)} = 6.46 \pm 0.12 {~\rm GeV}$, $\Gamma_{\Omega_b(3/2^-)} = 58{^{+65}_{-33}} {~\rm MeV}$, $M_{\Sigma_b(5/2^-)}-M_{\Sigma_b(3/2^-)}= 13 \pm 5 {~\rm MeV}$, $M_{\Xi_b^{\prime}(5/2^-)}-M_{\Xi_b^{\prime}(3/2^-)} = 12 \pm 5 {~\rm MeV}$, and $M_{\Omega_b(5/2^-)}-M_{\Omega_b(3/2^-)} = 11 \pm 5 {~\rm MeV}$. We propose to search for them in further LHCb experiments., Comment: 18 pages, 5 figures, 4 tables, published in PRD. arXiv admin note: text overlap with arXiv:1703.07703

We apply the method of QCD sum rules to study the structure $X$ newly observed by the BESIII Collaboration in the $\phi \eta^\prime$ mass spectrum in 2.0-2.1 GeV region in the $J/\psi \rightarrow \phi \eta \eta^\prime$ decay. We construct all the $s s \bar s \bar s$ tetraquark currents with $J^{PC} = 1^{+-}$, and use them to perform QCD sum rule analyses. One current leads to reliable QCD sum rule results and the mass is extracted to be $2.00^{+0.10}_{-0.09}$ GeV, suggesting that the structure $X$ can be interpreted as an $s s \bar s \bar s$ tetraquark state with $J^{PC} = 1^{+-}$. The $Y(2175)$ can be interpreted as its $s s \bar s \bar s$ partner having $J^{PC} = 1^{--}$, and we propose to search for the other two partners, the $s s \bar s \bar s$ tetraquark states with $J^{PC} = 1^{++}$ and $1^{-+}$, in the $\eta^\prime f_0(980)$, $\eta^\prime K \bar K$, and $\eta^\prime K \bar K^*$ mass spectra., Comment: 8 pages, 5 figures, 1 table, suggestions and comments are welcome

We use the method of light-cone sum rules to study the electromagnetic transition of the $\Xi^{*++}_{cc}$ into $\Xi^{++}_{cc}\gamma$, whose decay width is estimated to be $13.7~{^{+17.7}_{-~7.9}}$ keV. This value is large enough for the $\Xi^{*++}_{cc}$ to be observed in the $\Xi^{++}_{cc}\gamma$ channel, and we propose to continually search for it in future LHCb and BelleII experiments., Comment: 9 pages, 1 figure, 2 tables, accepted by PRD

We investigate the newly observed $X(4500)$ and $X(4700)$ based on the diquark-antidiquark configuration within the framework of QCD sum rules. Both of them may be interpreted as the $D$-wave $cs\bar{c}\bar{s}$ tetraquark states of $J^P = 0^+$, but with opposite color structures, which is remarkably similar to the result obtained in Ref.~\cite{Chen:2010ze} that the $X(4140)$ and $X(4274)$ can be both interpreted as the $S$-wave $cs\bar{c}\bar{s}$ tetraquark states of $J^P = 1^+$, also with opposite color structures. However, the extracted masses and these suggested assignments to these $X$ states do depend on these running quark masses where $m_s (2 \mbox{ GeV}) = 95 \pm 5$ MeV and $m_c (m_c) = 1.23 \pm 0.09$ GeV. As a byproduct, the masses of the hidden-bottom partner states of the $X(4500)$ and $X(4700)$ are extracted to be both around 10.64 GeV, which can be searched for in the $\Upsilon \phi$ invariant mass distribution., Comment: 6 pages, 4 figures. Accepted by Eur. Phys. J. C

We study the mass spectra of hidden-charm pentaquarks having spin $J = {1\over2}/{3\over2}/{5\over2}$ and quark contents $uud c \bar c$. We systematically construct all the relevant local hidden-charm pentaquark currents, and select some of them to perform QCD sum rule analyses. We find that the $P_c(4380)$ and $P_c(4450)$ can be identified as hidden-charm pentaquark states composed of an anti-charmed meson and a charmed baryon. Besides them, we also find a) the lowest-lying hidden-charm pentaquark state of $J^P = 1/2^-$ has the mass $4.33^{+0.17}_{-0.13}$ GeV, while the one of $J^P = 1/2^+$ is significantly higher, that is around $4.7-4.9$ GeV; b) the lowest-lying hidden-charm pentaquark state of $J^P = 3/2^-$ has the mass $4.37^{+0.18}_{-0.13}$ GeV, consistent with the $P_c(4380)$ of $J^P = 3/2^-$, while the one of $J^P = 3/2^+$ is also significantly higher, that is above $4.6$ GeV; c) the hidden-charm pentaquark state of $J^P = 5/2^-$ has a mass around $4.5-4.6$ GeV, slightly larger than the $P_c(4450)$ of $J^P = 5/2^+$., Comment: 18 pages, 5 figures and 3 tables. Accepted by Eur. Phys. J. C

We systematically construct tetraquark currents of $I^GJ^{PC}=1^-1^{++}$ and classify them into types $\mathbf{A}$ (antisymmetric), $\mathbf{S}$ (symmetric) and $\mathbf{M}$ (mixed), based on flavor symmetries of diquarks and antidiquarks composing the tetra quark currents. We use tetraquark currents of type $\mathbf{M}$ to perform QCD sum rule analyses, and find a tetraquark current $\eta^M_{5\mu}$ with quark contents $q s\bar q \bar s$($q=u$ or $d$) leading to a mass of $1.44 \pm 0.08$ GeV consistent with the $a_1(1420)$ state recently observed by the COMPASS collaboration. Our results support tetraquark explanations for both $a_1(1420)$ and $f_1(1420)$, assuming that they are isospin partners. We also study their possible decay patterns. As tetraquark candidates, the possible decay modes of $a_1(1420)$ are $S$-wave $a_1(1420) \rightarrow K^*(892)K$ and $P$-wave $a_1(1420)\rightarrow f_0(980) \pi$ while the possible decay patterns of $f_1(1420)$ are $S$-wave $f_1(1420) \rightarrow K^*(892)K$ and $P$-wave $f_1(1420) \rightarrow a_0(980) \pi$. We speculate that $a_1(1420)$ is partly responsible for the large isospin violation in the $\eta(1405)\to f_0(980)\pi_0$ decay mode which is reported by BESIII collaboration in the $J/\psi\to\gamma 3\pi$ process., Comment: 15 pages, 8 figures. Accepted by Phys. Rev. D

We study the D-wave c_bar s heavy meson doublets (1^-,2^-) and (2^-,3^-) using the method of QCD sum rule in the framework of heavy quark effective theory. Choosing the same threshold values omega_c around 2.7 Gev, we calculate the masses of the 1^- and 3^- states. They are m_{D*_{s1}} = 2.81 \pm 0.10 GeV and m_{D*_{s3}} = 2.85 \pm 0.08 GeV, consistent with the newly observed D*_{s1}(2860) and D*_{s3}(2860) states by LHCb. The masses of their 2^- partners are calculated to be 2.82 \pm 0.10 and 2.81 \pm 0.08 GeV. The mass splittings within the same doublet are calculated to be m_{D_{s2}} - m_{D*_{s1}} = 0.016 \pm 0.007 GeV and m_{D*_{s3}} - m_{D'_{s2}} = 0.039 \pm 0.014 GeV., Comment: 8 pages, 6 figures, accepted by PRD

We systematically construct $I(J^P)=0(3^+)$ six-quark local interpolating currents without derivative operators. We discuss the best choice of operator, and select three $\Delta$-$\Delta$ like operators to perform QCD sum rule analyses to calculate the mass of the $d^*(2380)$. The mass extracted from this analysis is $M_{d^*} = 2.4\pm0.2$ GeV, consistent with the $d^*(2380)$ mass observed by the WASA detector at COSY. We also obtain a sum-rule lower mass bound $M_{d^*} > 2.25$ GeV. We also consider the effect of mixing of singlet dibaryon fields with the same quantum numbers, and perform the QCD sum rule analysis of the mixed interpolating current and extract the mass of the $d^*(2380)$ and its lower mass bound. With optimized mixing parameters, we find that the mixed current does not change the numerical result significantly., Comment: 9 pages, 4 figures

We evaluate energy levels of the K-pi system in the K* channel in finite volume using chiral unitary theory. We use these energy levels to obtain K-pi phase shifts, and then obtain the K* mass and its decay width. We investigate their dependence on the pion mass and compare this with Lattice QCD calculations. We also compare our method with the standard Luscher approach, and solve the inverse problem to obtain the K-pi phase shifts from these "synthetic" lattice data., Comment: 12 pages, 15 figures, accepted by prd