Search

Within the method of parity-projected QCD sum rules, we study the mass spectra of light hybrid baryons with $I(J^{P})=1/2(1/2^{\pm}), 3/2(1/2^{\pm}), 1/2(3/2^{\pm}), 3/2(3/2^{\pm})$ by constructing the local $qqqg$ interpolating currents. We calculate the correlation functions up to dimension eight condensates at the leading order of $\alpha_{s}$. The stable QCD Lapalce sum rules can be established for the positive-parity $N_{1/2^+}, \Delta_{3/2^+}, \Delta_{1/2^+}$ and negative-parity $N_{1/2^-}, N_{3/2^-}, \Delta_{1/2^-}$ channels to extract their mass spectra. The lowest-lying hybrid baryons are predicted to be the negative-parity $N_{1/2^-}$ state around 2.28 GeV and $\Delta_{1/2^-}$ state around 2.64 GeV. These hybrid baryons mainly decay into conventional baryon plus meson final states. We propose to search for the light hybrid baryons through the $\chi_{cJ}/\Upsilon$ decays via the three-gluon emission mechanism in BESIII and BelleII experiments. Our studies of the light hybrid baryons will be useful for understanding the excited baryon spectrum and the behavior of gluonic degrees of freedom in QCD., Comment: 6 pages, 5 figures

We explore toponium, the smallest known quantum bound state of a top quark and its antiparticle, bound by the strong force. With a Bohr radius of $8 \times 10^{-18}$~m and a lifetime of $2.5 \times 10^{-25}$ s, toponium uniquely probes microphysics. Unlike all other hadrons, it is governed by ultraviolet freedom, exhibiting feeble interactions at distances much smaller than $10^{-15}$ m, rather than infrared slavery that characterizes powerful interactions at approximately $10^{-15}$~m. This distinction offers novel insights into quantum chromodynamics. Our analysis reveals a toponium signal exceeding five standard deviations in the distribution of the cross section ratio between $e^+e^- \rightarrow b\bar{b}$ and $e^+e^- \rightarrow q\bar{q}$ ($q=b,~c,~s,~d,~u$), based on 400~fb$^{-1}$ {(1 fb = $10^{-43}~{\rm m}^2$)} of data collected at around 341~GeV, driven by quantum interference. This discovery enables a top quark mass measurement with an uncertainty reduced by a factor of ten compared to current precision levels. Detection prospects at the Circular Electron Positron Collider or the Future Circular Lepton Collider underscore their potential to revolutionize our understanding of quantum mechanics., Comment: 30 pages, 4 pages

We carry out a comprehensive investigation on the radiative decays of $P$-wave bottom baryons using the light-cone sum rule method. We analyze their electromagnetic transitions into ground-state bottom baryons together with a photon. Together with their mass spectra and strong decays investigated in Refs. \cite{Yang:2020zrh,Tan:2023opd}, a rather complete QCD sum rule study has been done to understand the $P$-wave singly bottom baryons within the framework of heavy quark effective theory. As summarized in Tables~\ref{tab:candidate}/\ref{tab:candidate6f}, some $P$-wave bottom baryons have limited strong decay widths so that their radiative decay widths become non-negligible. We propose to study these excited bottom baryons and their radiative decays in the future Belle-II, BESIII, and LHCb experiments., Comment: 24 pages, 10 figures, 7 tables, suggestions and comments welcome

The methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory have been widely applied to study the singly heavy baryons, and especially, we have applied these methods to predict not only the mass and width of the $\Xi_b(6087)^0$ recently discovered by LHCb, but also its observation channel and its mass difference from the $\Xi_b(6100)^-$. We apply the same approach to perform a complete study on the $P$-wave bottom baryons of the $SU(3)$ flavor $\mathbf{\bar 3}_F$ and investigate their fine structure. Besides the $\Lambda_b(5912)^0$, $\Lambda_b(5920)^0$, $\Xi_b(6087)^0$, and $\Xi_b(6100)^-$, our results suggest the existence of the other two $\Lambda_b$ and two $\Xi_b$ baryons, whose widths are limited. They are the $\Lambda_b(J^P = 3/2^-)$ with the mass and width about $(5.93^{+0.13}_{-0.13}~{\rm GeV},\,0.0^{+12.0}_{-~0.0}~{\rm MeV})$, the $\Lambda_b(5/2^-)$ with $(5.94^{+0.13}_{-0.13}~{\rm GeV},\,\approx0~{\rm MeV})$, the $\Xi_b(3/2^-)$ with $(6.10^{+0.15}_{-0.10}~{\rm GeV},\,1.4{^{+11.6}_{-~1.4}}~{\rm MeV})$, and the $\Xi_b(5/2^-)$ with $(6.11^{+0.15}_{-0.10}~{\rm GeV},\,1.0{^{+7.4}_{-1.0}}~{\rm MeV})$. Their mass splittings are calculated to be $M_{\Lambda_b(5/2^-)} - M_{\Lambda_b(3/2^-)} = 17\pm7~{\rm MeV}$ and $M_{\Xi_b(5/2^-)} - M_{\Xi_b(3/2^-)} = 14\pm7~{\rm MeV}$. All these baryons are explained as the $P$-wave bottom baryons of the $\rho$-mode, where the orbital excitation is between the two light quarks. However, the existence of this mode is still controversial, so their experimental searches can verify both our approach and the existence of the $\rho$-mode, which can significantly improve our understanding on the internal structure of hadrons., Comment: 6 pages, 2 figures, 1 table, revised version to be published in EPJC

We conduct an investigation on the $1P$- and $2P$-wave charmed baryons 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 $\Lambda_c(2910)^+$, $\Lambda_c(2940)^+$, and $\Xi_c(3123)^+$ can be well interpreted as the $2P$-wave charmed baryons of $J^P=1/2^-$ and $3/2^-$, belonging to the $SU(3)$ flavor $\mathbf{\bar 3}_F$ representation. Moreover, the $\Xi_c(3123)^+$ possesses a partner state characterized by $J^P=1/2^-$, denoted as $\Xi_c(1/2^-,2P)$. Our analysis predicts its mass and width to be $m_{\Xi_c(1/2^-,2P)} - m_{\Xi_c(3123)^+} = -18\pm{7}$MeV and $\Gamma_{\Xi_c(2P,1/2^-)}=31^{+170}_{-27}$MeV, with $m_{\Xi_c(3123)^+} = 3122.9\pm{1.3}$MeV. We propose to search for it in the $\Xi_c(1/2^-,2P)\to \Sigma_c K$ decay channel., Comment: 20 pages, 7 figures,5 tables, suggestions and comments welcome. arXiv admin note: text overlap with arXiv:2205.07224

Recently, the Belle Collaboration has measured the $\Lambda_c^+ \to \eta \Lambda \pi^+$ decay and reported the $\eta\Lambda$ and $\Lambda\pi^+ $ invariant mass distributions, which show the clear signals of the resonances $\Lambda(1670)$ and $\Sigma(1385)$, respectively. Based on our previous works [Eur. Phys. J. C 76 (2016) 496 and Phys. Rev. D 95 (2017) 074024], we re-analyze this process by considering the $S$-wave $\eta\Lambda$ and $\eta\pi^+$ final state interactions within the chiral unitary approach, which dynamically generate the $\Lambda(1670)$ and $a_0(980)$, respectively. Our results are in good agreement with the Belle measurements, which supports the molecular nature of the $\Lambda(1670)$ and $a_0(980)$. In addition, the $\eta \pi^+$ invariant mass distributions are also computed and a cusp structure of $a_0(980)$ is cleary shown around the $K\bar{K}$ mass threshold., Comment: 8 pages, 9 figures

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 use QCD sum rules to study mass spectra of $P$-wave charmed baryons of the $SU(3)$ flavor $\mathbf{6}_F$. We also use light-cone sum rules to study their $S$- and $D$-wave decays into ground-state charmed baryons together with light pseudoscalar and vector mesons. We work within the framework of heavy quark effective theory, and we also consider the mixing effect. Our results can explain many excited charmed baryons as a whole, including the $\Sigma_c(2800)^0$, $\Xi_c(2923)^0$, $\Xi_c(2939)^0$, $\Xi_{c}(2965)^{0}$, $\Omega_c(3000)^0$, $\Omega_c(3050)^0$, $\Omega_c(3066)^0$, $\Omega_c(3090)^0$, and $\Omega_c(3119)^0$. Their masses, mass splittings within the same multiplets, and decay properties are extracted for future experimental searches., Comment: 29 pages, 6 figures, 6 tables, to be published in PRD

We systematically study mass spectra and decay properties of $P$-wave $\Xi_c^\prime$ baryons of the $SU(3)$ flavor $\mathbf{6}_F$, 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 three excited $\Xi_c^0$ baryons recently observed by LHCb can be well explained as $P$-wave $\Xi_c^\prime$ baryons: the $\Xi_c(2923)^0$ and $\Xi_c(2939)^0$ are partner states of $J^P = 1/2^-$ and $3/2^-$ respectively, both of which contain one $\lambda$-mode orbital excitation; the $\Xi_c(2965)^0$ has $J^P = 3/2^-$, and also contains one $\lambda$-mode orbital excitation. We propose to search for another $P$-wave $\Xi_c^\prime$ state of $J^P = 5/2^-$ in the $\Lambda_c K/\Xi_c \pi$ mass spectral in future experiments. Its mass is about $56^{+30}_{-35}$ MeV larger than the $\Xi_c(2965)^0$, and its width is about $18.1^{+19.7}_{-~8.3}$ MeV., Comment: 16 pages, 1 figure, 3 tables, accepted by PRD

We investigate $P$-wave bottom baryons of the $SU(3)$ flavor $\mathbf{6}_F$, and systematically study their $D$-wave decays into ground-state bottom baryons and pseudoscalar mesons. Together with [PRD91, 054034 (2015); PRD92, 114007 (2015); PRD95, 094008 (2017); EPJC80, 80 (2020)], a rather complete study is performed on both mass spectra and decay properties of $P$-wave bottom baryons, using the method of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. Among all the possibilities, we find four $\Sigma_b$, four $\Xi^\prime_b$, and six $\Omega_b$ baryons, with limited widths and so capable of being observed. Their masses, mass splittings within the same multiplets, and decay properties are extracted (summarized in Table V) for future experimental searchings., Comment: 19 pages, 5 figures, 5 tables, some errors were detected when studying $P$-wave bottom baryons of the $SU(3)$ flavor $\mathbf{6}_F$ with $J^P = 5/2^-$

We study the $\Lambda_b(6146)^0$ and $\Lambda_b(6152)^0$ recently observed by LHCb using the method of QCD sum rules within the framework of heavy quark effective theory. Our results suggest that they can be interpreted as $D$-wave bottom baryons of $J^P = 3/2^+$ and $5/2^+$ respectively, both of which contain two $\lambda$-mode excitations. We also investigate other possible assignments containing $\rho$-mode excitations. We predict masses of their strangeness partners to be $m_{\Xi_b(3/2^+)} = 6.26^{+0.11}_{-0.14}$ GeV and $m_{\Xi_b(5/2^+)} = 6.26^{+0.11}_{-0.14}$ GeV with the mass splitting $\Delta M = 4.5^{+1.9}_{-1.5}$ MeV, and propose to search for them in future LHCb and CMS experiments., Comment: 14 pages, 6 figures, 1 table, revised version

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