This study investigates the properties of the $T_{ψψ}$ tetraquark candidates within a coupled-channels calculation of the $c\bar c- c\bar c$ system, specifically focusing on the $J^P=0^\pm$, $1^\pm$, and $2^\pm$ sectors. The analysis includes various channels containing a $J/ψ$, $ψ^\prime$, $η_c$, and $η_c^\prime$ meson. By searching for poles in the scattering matrix, a total of 29 states in different $J^P$ sectors with masses ranging from 6.1 to 7.6 GeV/c$^2$ are identified. The study further investigates the masses, widths and branching ratios of these states, leading to the identification of two potential candidates for the experimental $T_{ψψ}(6200)$ tetraquark, one candidate for $T_{ψψ}(6600)$, two for $T_{ψψ}(6700)$, four for $T_{ψψ}(6900)$, and three for $T_{ψψ}(7200)$ tetraquarks. Additionally, the paper discusses strategies to discriminate between different candidates and explores possible detection channels for further $c\bar c- c\bar c$ states.
Exploring open-charm decay mode $Λ_c\barΛ_c$ of charmonium-like state $Y(4630)$
新观测到的$X, Y, Z$奇异态肯定不是标准的$Q\bar Q'$结构，因此它们的存在对我们对强子物理基本原理的理解构成了挑战。因此，对它们的衰变模式的研究必将对相关物理学的发展有所启发。一般来说，四夸克态可能是分子态、四夸克态或它们的混合态。在本工作中，我们采用了这样的假设：$Y(4630)$是由一个双夸克和一个反双夸克组成的类粲偶素四夸克态。如果这是真的，它的有利衰变模式应该是$Y(4630)$衰变成开魅重子对，因为这种跃迁是通过强相互作用发生的，并且是超OZI允许的。本文在夸克对产生模型的框架下计算了$Y(4630)\toΛ_c\barΛ_c$的衰变宽度。在一定的误差范围内，我们计算的四夸克组态的部分宽度的数值结果与Belle数据相吻合。
In this article, we utilise the non-relativistic potential model to calculate the mass-spectra of all bottom [$bb][\bar{b}\bar{b}$] and heavy-light bottom [$bq][\bar{b}\bar{q}$] (q=u,d) tetraquark states in diquark-antidiquark approximation. The four-body problem is reduced into two-body problems by numerically solving the $Schr\ddot{o}dinger$ equation using a cornell-inspired potential along with relativistic correction term. The splitting structure of the tetraquark spectrum is described using spin-dependent terms (spin-spin, spin-orbit, and tensor). We have successfully calculated and predi…
Exploring $T_{ΥΥ}$ tetraquark candidates in a coupled-channels formalism
Universidad de Salamanca（萨拉曼卡大学）；Instituto Universitario de Física Fundamental y Matemáticas (IUFFyM), Universidad de Salamanca（萨拉曼卡大学基础物理与数学大学研究所）；Universidad Pablo de Olavide（巴勃罗·德·奥拉维德大学）
The exact eigenenergies of the $T_{4c}=[cc][\bar{c}\bar{c}]$, $T_{4b}=[bb][\bar{b}\bar{b}]$, and $T_{2[bc]}=[bc][\bar{b}\bar{c}]$ tetraquarks are calculated within the extended transitional Hamiltonian approach, in which the so-called Bethe \emph{ansatz} within an infinite-dimensional Lie algebra is used. We fit the parameters appearing in the transitional region from phenomenology associated with potential candidates of tetraquarks. The rotation and vibration transitional theory seems to provide a better description of heavy tetraquarks than other attempts within the same formalism. Our resul…
The newly observed hidden-charm tetraquark state $Z_{cs}(3985)$, together with $Z_c(3900)$ and $X(4020)$, are studied in the combined theoretical framework of the effective range expansion, compositeness relation and the decay width saturation. The elastic effective-range-expansion approach leads to sensible results for the scattering lengths, effective ranges and the compositeness coefficients, $i.e.$, the probabilities to find the two-charm-meson molecule components in the tetraquark states. The coupled-channel formalism by including the $J/ψπ$ and $D\bar{D}^*/\bar{D}D^*$ to fulfill the cons…
Hadron spectroscopy is a powerful tool for testing the standard model and for the search of new physics. In this work, we create a tetraquark model from a di-meson interaction inspired by Jacobi coordinates. We consider mesons as thick points and quantify their interaction with the quark-antiquark interaction through a factor k (that takes approximately the value 2) in a central phenomenological potential, reducing the four-body problem finally to a one body equivalent problem. The eigenproblem is solved using a combination of the DVR method and perturbation theory in a C++ code. We obtain a m…
The low-lying $sQ\bar{q}\bar{q}$ $(q=u,\,d,\, Q=c,\,b)$ tetraquark states with $J^P=0^+$, $1^+$ and $2^+$, and in the isoscalar and isovector sectors, are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron and multiquark phenomenology, and thus all results presented here are pure predictions. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account; this includes meson-meson, diquark-antidiquark and K-type arrangements of qu…
在组分夸克模型的框架下研究了四夸克系统$c\bar c n\bar n$.利用不同类型的夸克-夸克势，用超球谐方法求解了四体薛定谔方程。探索不同Isosin配置的低层$J^{PC}$态，没有发现四夸克束缚态。特别感兴趣的是X（3872）可能的四夸克结构。我们排除了这种粒子是一个紧凑的四夸克系统的可能性，除非额外的相关性，无论是在双夸克的形式或在相互作用势的水平，没有考虑在简单的夸克模型没有贡献。
DeepQuark: A Deep-Neural-Network Approach to Multiquark Bound States
School of Physics, Peking University, Beijing 100871, China（北京大学物理系）；School of Physics, Southeast University, Nanjing 211189, China（东南大学物理系）；School of Physics（物理系）；Center of High Energy Physics, Peking University, Beijing 100871, China（北京大学高能物理中心）
The LHCb collaboration has found that the production rate of $X(3872)$ in proton-proton collisions decreases as final state particle multiplicity increases. Moreover, the ALICE experiment at CERN has observed that the number of deuterons produced increases with multiplicity, a behavior that is qualitatively different from that of the $X(3872)$. These experimental findings may point to a compact structure for the $X(3872)$ or, at least, that its hadronization could proceed through a charm-anticharm core. We have recently used a diffusion Monte Carlo method to solve the many-body Schrödinger equ…
Exploring ultra-high energy neutrino experiments through the lens of the transport equation
Galileo Galilei Institute for Theoretical Physics（伽利略·伽利莱理论物理研究所）；Università degli Studi La Sapienza（罗马第一大学）；INFN Sezione di Firenze（意大利国家核物理研究院佛罗伦萨分部）
Holographic spectral functions of exotic spin-1 mesons
College of Physics and Electronic Engineering, Hainan Normal University（海南师范大学物理与电子工程学院）；School of Physics and Telecommunications Engineering, Zhoukou Normal University（周口师范学院物理与电信工程学院）
Recently, the hidden charm tetraquark states $Z_{cs}(3985)$ and $Z_{cs}(4000)$ with strangeness were observed by the BESIII and LHCb collaborations, respectively, which are great breakthroughs for exploring exotic QCD structures. The first and foremost question is whether they are the same state. In this work, we explore the implications of the narrower state $Z_{cs}(3985)$ in BESIII and the wider one $Z_{cs}(4000)$ in LHCb as two different states. Within a solvable nonrelativistic effective field theory, we include the possible violations of heavy quark spin symmetry and SU(3) flavor symmetry…
