arXiv subjects

Takayuki Matsuki

Publications and source records attributed to Takayuki Matsuki.

At least 19 recordsLinked to original sources

arXiv2022

Identifying the contribution of higher $ρ$ mesons around 2 GeV in the $e^+ e^- \to ωπ^0$ and $e^+ e^- \to ρη^{\prime}$ processes

The properties of the light vector meson states around 2.0 GeV have been poorly understood for a long time, which has become a barrier to the expansion to higher light vector meson spectrum. Recently, the BESIII collaboration released the measurements of the $e^+ e^- \to ωπ^0$ and $e^+ e^- \to ρη^{\prime}$ reactions above 2.0 GeV, both of which are ideal processes to study the isovector $ρ$ meson family. In this work, through carrying out a combined analysis of the Born cross section data for the above two processes with the theoretical support on mass spectrum, and production and strong decay behaviors of the $ρ$ meson family around 2.0 GeV, we identify the enhancement structure near 2034 MeV observed in $e^+e^-\toωπ^0$ to be the interference contribution from two resonances $ρ(1900)$ and $ρ(2150)$, and another enhancement structure at 2111 MeV reported in $e^+e^-\toρη^{\prime}$ to be the contributions from $ρ(2000)$ and $ρ(2150)$. This conclusion means that the $e^+e^-\toωπ^0$ and $e^+e^-\toρη^{\prime}$ are the excellent golden channels to establish $ρ(1900)$ and $ρ(2000)$, especially for a $D$-wave state $ρ(2000)$, whose experimental search in the $e^+e^-$ collision should be quite challenging. The relevant cross section measurements with higher precision are expected in the future BESIII and Belle II experiments.

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arXiv2022

$\mathbf{Υ(10753)\toΥ(nS)π^+π^-}$ decays induced by hadronic loop mechanism

In this work, we investigate the $Υ(10753)\toΥ(nS)π^+π^-$ ($n=1,2,3$) processes by considering the hadronic loop mechanism, where $Υ(10753)$ is assigned to a conventional bottomonium in the $4S$-$3D$ mixing scheme. Our results of the concerned processes own considerable branching ratios, which can reach up to the order of magnitude of $10^{-4}-10^{-3}$. We should indicate that the measured $Γ_{e^+e^-}\times\mathcal{B}[Υ(10753)\toΥ(nS)π^+π^-]$ values given by Belle can be reproduced well. This fact supports the former bottomonium assignment to the $Υ(10753)$ in the $4S$-$3D$ mixing scheme. Obviously, it is a good opportunity for the ongoing Belle II experiment if the predicted result in this work can be tested further.

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arXiv2021

Evidence supporting the existence of $P_c(4380)^{\pm}$ from the recent measurements of $B_s \to J/ψp\bar{p}$

Very recently, the LHCb collaboration released the newest measurements of $B_s \to J/ψp\bar{p}$, where an enhancement structure near 4.34 GeV was observed in the invariant mass spectrum of $J/ψp$ with the statistical significance of $3.1-3.7$ $σ$. In this work, by performing a combined analysis for the three invariant mass spectra of $B_s \to J/ψp\bar{p}$, we find that this $J/ψp$ structure near 4.34 GeV can correspond to the contributions from the $P_c(4380)^+$ state with the assumption of $J^{P}=3/2^{-}$ together with the reflections of $B_s \to (f_2^{*} \to p\bar{p})J/ψ$. Here, $P_c(4380)$ was first observed in $Λ_b \to J/ψp K$ but not confirmed in the updated LHCb data in 2019, and $f_2^{*}$ means the exciting light isoscalar tensor meson around 2.0 GeV. Thus, this provides a possible evidence to support the existence of the pentaquark $P_c(4380)$. Specifically, the assumed spin parity $J^{P}=3/2^{-}$ of $P_c(4380)$ is consistent with a prediction of the theoretical explanation of an $S$-wave $\bar{D}Σ_c^*$ molecular bound state.

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arXiv2021

Magic mixing angles for doubly heavy baryons

We study the so-called magic mixing angles for doubly heavy baryons. Defining that a magic mixing angle rotates states with definite $^{2S+1}(l_λ)_J$ to make them heavy-quark symmetric states, we derive the magic mixing angle only in the case $L_ρ=0$ between the heavy quark symmetric states with quantum numbers $\left(J, j_\ell\right)$ and the states with $\left(J, s_q+j_ρ\right)=\left(J, \{^4l_λ/^2l_λ\}\right)$ for a doubly heavy baryon in the standard $ρ-λ$ configuration, where $\vec j_\ell=\vec l_λ+\vec s_q$, $\vec s_ρ=\vec s_{Q1}+\vec s_{Q2}$, and $\vec j_ρ=\vec s_ρ+\vec L_ρ$. We discuss how this mixing angle affects model building for a doubly heavy baryon.

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arXiv2021

Charmonium decays into $Λ_c\barΛ_c$ pair governed by the hadronic loop mechanism

In this work, we investigate the open-charm decay process $ψ\toΛ_c\barΛ_c$ via the hadronic loop mechanism for vector charmonia above $Λ_c\barΛ_c$ threshold. The branching ratios of these vector charmonium states to $Λ_c\barΛ_c$ are estimated. The charmonium explanation of the $Y(4630)$ observed in $e^+e^- \to Λ_c\barΛ_c$ is tested. Furthermore, for the predicted higher vector charmonia above 4.7 GeV, the branching ratios $\mathcal{B}[ψ(nS)\toΛ_c\barΛ_c]$ with $n=7,8,9$ are found to be of the order of magnitude of $10^{-4}-10^{-3}$ while $\mathcal{B}[ψ(mD)\toΛ_c\barΛ_c]$ with $m=6,7,8$ are of the order of magnitude of $10^{-3}-10^{-2}$. The experimental signals of these missing charmonium states are discussed. The search for them may be an interesting topic in the future BESIII and Belle II experiments.

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arXiv2021

Toward charged $Z_{cs}(3985)$ structure under a reflection mechanism

Very recently, the BESIII collaboration reported a charged hidden-charm structure with strangeness in the recoil mass of $K^+$ of a process $e^+e^-\to D_s^{*-}D^0K^+$ or $D_s^{-}D^{*0}K^+$, which is named as $Z_{cs}(3985)^{-}$. The newly observed charged structure can be treated as a partner structure with strangeness of well-known $Z_{c}(3885)^{-}$ reported in a process $e^+e^-\to D^{*-}D^0π^+$. In this work, we propose a novel picture to understand the nature of $Z_{cs}(3985)$. By performing a combined analysis for the line shape of the recoil mass distribution of $K^+$ at five energy points $\sqrt{s}=4.628, 4.641, 4.661, 4.681, 4.698$ GeV, we find that the $Z_{cs}(3985)$ can be explained as a reflection structure of charmed-strange meson $D_{s2}^{*}(2573)$, which is produced from the open-charm decay of $Y(4660)$ with a $D_s^*$ meson. Furthermore, we predicted the angular distribution of final state $D_s^{*-}$ in process $e^+e^-\to D_s^{*-}D^0K^+$ based on our proposed reaction mechanism, which may be an essential criterion to test the non-resonant nature of $Z_{cs}(3985)$ further.

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arXiv2021

Deciphering the light vector meson contribution to the cross sections of $e^+e^-$ annihilations into the open-strange channels through a combined analysis

In this work, we perform a combined analysis to the measured data of the cross section of open-strange processes $e^+e^- \to K^+K^-$, $e^+e^- \to K\bar{K}^{*}+c.c.$, $e^+e^- \to K^{*+}K^{*-}$, $e^+e^- \to K_1(1270)^+K^-$, $e^+e^- \to K_1(1400)^+K^-$, $e^+e^- \to K_2^{*}(1430)\bar{K}+c.c.$ and $e^+e^- \to K(1460)^+K^-$ with the support of study of hadron spectroscopy. We reveal the contribution of the possible light vector mesons around 2 GeV to reproduce the cross section data of the reported open-strange processes from $e^+e^-$ annihilation which may provide a new perspective to construct the light vector meson family and understand the $Y(2175)$.

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arXiv2021

Identifying $D_{sJ}^*(2860)$ as a four resonance states through strong decay analysis

Experimentally observed excited strange charmed mesons $D_{s0}^*(2317)^{\pm}$, $D_{s1}(2460)^{\pm}$, $D_{s1}(2536)^{\pm}$, $D_{s2}^*(2573)^{\pm}$, $D_{s1}^*(2700)^{\pm}$, $D_{s1}^*(2860)^{\pm}$, $D_{s3}^*(2860)^{\pm}$, and $D_{sJ}(3040)^{\pm}$ are identified tentatively according to their spin, parity, and masses. Using the heavy quark effective theory in the leading order approximation, we study their strong decays to ground state charmed mesons plus light pseudoscalar mesons. The branching ratios are classified, $(D_{s0}^*(2317), D_{s1}(2460))$ as $(1^3P_0, 1P_1)$ and $(D_{s1}(2536), D_{s2}^*(2573))$ as $(1P_1^{\prime}, 1^3P_2)$, in heavy quark doublets. The $D_{s1}^*(2700)$ as $2^3S_1$ and its spin partner, $2^1S_0$ is still missing in the experiment. Its strong decay behavior is predicted. The assignment of $D_{sJ}^*(2860)$ as four resonance states $D_{s1}^*(2860)$, $D_{s2}^*(2860)$, $D_{s2}^{*\prime}(2860)$, $D_{s3}^*(2860)$ is favored, where for $D_{s3}^*(2860)^{\pm}$ the mass should be expected to higher than 2.86 GeV. The $D_{sJ}(3040)$ is more likely to be 2$P_1$ state. We construct the Regge trajectories of experimentally observed strange charmed mesons in $(M^2, J)$ and $(M^2, n_r)$ planes, which estimate the masses of $1^3D_3$, $1^3F_4$, $1D_2$, $1^1F_3$, $1D_2^{\prime}$, $1F_3^{\prime}$, $3^3S_1$, and $3P_1$ states with fixing the slopes and intercepts of the Regge lines. Moreover, the strong decay rates and the branching ratios of these higher excited states are also examined, which distinguished the dominant decay channels for these higher excited states. Our results could provide some important clues in LHCb, BESIII, KEK-B, and the forthcoming Belle II and $\overline{\mbox{\sffamily P}}${\sffamily ANDA} experiments.

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arXiv2021

Mapping a new cluster of charmoniumlike structures at $e^+e^-$ collisions

In this work, we find a Critical Energy induced Enhancement (CEE) mechanism for the general three-body open-charm process at the $e^+e^-$ collisions, which utilizes the peculiar kinematic behavior of the $e^+e^-$ annihilation process involving three-body final states. We present a general analysis of a three-body process $e^+e^-\to BC\to B(C\to DE)$. When the center-of-mass (CM) energy of the $e^+e^-$ collision satisfies a critical relation $\sqrt{s}=m_B+m_C$, there clearly exists the reflection peak of an intermediate $C$ state near the threshold of the invariant mass distribution of $m_{BE}$ or $m_{BD}$, whose formation is very sensitive to the CM energy. The reflection enhancement phenomenon induced at the critical energy means that a new cluster of charmoniumlike structures can be experimentally mapped. Taking an example of $e^+e^-\to D_s^{*-}D_{s2}^*(2573)^+ \to D_s^{*-}(D^0K^+)$, we further illustrate this novel phenomenon when $\sqrt{s}=4.680$ GeV. What is more important is that a series of optimal CM energy points to search for new charmoniumlike structures in three-body open-charm processes from $e^+e^-$ annihilation are suggested, which can be accessible at BESIII and further BelleII as a new research topic.

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arXiv2021

Predicting a new resonance as charmed-strange baryonic analog of $D_{s0}^*(2317)$

By an unquenched quark model, we predict a charmed-strange baryon state, namely, the $Ω_{c0}^d(1P,1/2^-)$. Its mass is predicted to be 2945 MeV, which is below the $Ξ_c\bar{K}$ threshold due to the nontrivial coupled-channel effect. So the $Ω_{c0}^d(1P,1/2^-)$ state could be regraded as the analog of the charmed-strange meson $D_{s0}^*(2317)$. It is a good opportunity for the running Belle II experiment to search for this state in the $Ω_c^{(*)}γ$ mass spectrum experiment in the future.

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arXiv2021

A Phenomenological analysis on isospin-violating decay of $X(3872)$

In a molecular scenario, we investigate the isospin-breaking hidden charm decay processes of $X(3872)$, i.e., $X(3872) \to π^+ π^- J/ψ$, $X(3872) \to π^+ π^- π^0 J/ψ$, and $X(3872)\to π^0χ_{cJ}$. We assume that the source of the strong isospin violation comes from the different coupling strengths of $X(3872)$ to its charged components $D^{\ast +} D^-$ and neutral components $D^{\ast 0 } \bar{D}^0$ as well as the interference between the charged meson loops and neutral meson loops. The former effect could fix our parameters by using the measurement of the ratio $Γ[X(3872) \to π^+ π^- π^0 J/ψ]/Γ[X(3872) \to π^+ π^- J/ψ]$. With the determined parameter range, we find that the estimated ratio $Γ[X(3872) \to π^0 χ_{c1}/Γ[X(3872) \to π^+ π^- J/ψ]$ is well consistent with the experimental measurement from the BESIII collaboration. Moreover, the partial width ratio of $π^0 χ_{cJ}$ for $J=0,1,2$ is estimated to be $1.77\sim1.65:1:1.09\sim1.43$, which could be tested by further precise measurements of BESIII and Belle II.

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arXiv2020

Fully-heavy structures in the invariant mass spectrum of $J/ψψ(3686)$, $J/ψψ(3770)$, $ψ(3686) ψ(3686)$, and $J/ψΥ(1S)$ at hadron colliders

Motivated by a recent successful dynamical explanation for the newly observed fully-charm structure $X(6900)$ in the mass spectrum of di-$J/ψ$ by LHCb [J.~Z.~Wang \textit{et al.} arXiv:2008.07430], in this work, we extend the same dynamical rescattering mechanism to predict the line shape of more potential fully-heavy structures in the invariant mass spectrum of $J/ψψ(3686)$, $J/ψψ(3770)$, $ψ(3686) ψ(3686)$, and $J/ψΥ(1S)$ at high energy proton-proton collisions, whose verification in experiments should be helpful to further clarify the nature of $X(6900)$. The above final states of vector heavy quarkonia can be experimentally reconstructed more effectively by a $μ^+μ^-$ pair in the muon detector compared with $Q\bar{Q}$ meson with other quantum numbers. Furthermore, the corresponding peak mass positions of each of predicted fully-heavy structures are also given. Our theoretical studies here could provide some valuable information for the future measurement proposals of LHCb and CMS, especially based on the accumulated data after completing Run III of LHC in the near future.

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arXiv2020

$D$ wave bottomonia production from $Z_b^{(\prime)}$ decay

In the present work, we investigate the dipion transitions between $Υ(5S)$ and $Υ_J(1D)$ with $J=1, 2, 3$. Our analysis indicates that the dominant sources of the anomalously large widths of $Υ(5S)\to Υ_J(1D) π^+ π^-$ should be $Z_b^{(\prime)}$, i.e., the dipion transitions occur via the cascade decays $Υ(5S)\to Z_b^{(\prime)\pm} π^\mp \to Υ_J(1D) π^+ π^-$. With the assumption that all the short ranged dynamics could be absorbed in a single cutoff with a model parameter $α$, the present estimations indicate that in a reasonable parameter range the measured branching ratios of $Υ(5S) \to Υ_J(1D) π^+ π^-$ can be reproduced in magnitude, which further proves that the decays via $Z_b^{(\prime)}$ dominate the dipion transitions of $Υ(5S)$ to $Υ_J(1D)$. Moreover, we also predict the ratios of the branching fractions of $Z_b^{(\prime)} \to Υ_J(1D) π$, which in our calculations are largely independent of the parameter $α$ and could be tested by further experiments in Belle II.

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arXiv2020

Universal non-resonant explanation to charmoniumlike structures $Z_c(3885)$ and $Z_c(4025)$

Different from the usual tetraquark assignment to charged $Z_c(3885)$ and $Z_c(4025)$ charmoniumlike structures, in this letter we propose a universal non-resonant explanation to decode these $Z_c$'s, which is based on a special dynamical behavior of $e^+e^-\to D^{(*)}\bar{D}^*π$. Our study shows that $Z_c(3885)$ and $Z_c(4025)$ are only the reflection from the $P$-wave charmed meson $D_1(2420)$ involved in $e^+e^-\to D^{(*)}\bar{D}^*π$. Obviously, the present work provides a unique perspective, which can be examined by future experiments like BESIII and BelleII.

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arXiv2020

Producing fully-charm structures in the $J/ψ$-pair invariant mass spectrum

Very recently, the LHCb Collaboration reported the observation of several enhancements in the invariant mass spectrum of a $J/ψ$ pair between 6.2 and 7.4 GeV. In this work, we propose the dynamical mechanism to mimic the experimental data of a di-$J/ψ$ mass spectrum given by LHCb, which is based on the reactions, where all the possible combinations of a double charmonium directly produced by a proton-proton collision are transferred into a final state $J/ψJ/ψ$. We find that the LHCb experimental data can be well reproduced. We further extend our framework to study a di-$Υ(1S)$ system, and give the line shape of a differential cross section of a partner process in a $b\bar{b}$ system on the invariant mass of $Υ(1S)Υ(1S)$, which shows that there should exist possible enhancements near $m_{Υ(1S)Υ(1S)}=$19.0, 19.3, 19.7 GeV in the $Υ(1S)$-pair invariant mass spectrum. These predictions can be tested in LHCb and CMS, which can be as a potential research issue in near future.

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arXiv2020

Possibility of charmoniumlike state $X(3915)$ as $χ_{c0}(2P)$ state

In this work, we seriously discuss whether $X(3915)$ can be treated as a $χ_{c0}(2P)$ state. Based on an unquenched quark model, we give the mass spectrum of the $χ_{cJ}(2P)$ states, where there are no free input parameters in our calculation. Our result shows that the mass gap between $χ_{c0}(2P)$ and $χ_{c2}(2P)$ can reach 13 MeV, which can reproduce the mass difference between $Z(3930)$ and $X(3915)$. Additionally, the calculated masses of $χ_{c0}(2P)$ and $χ_{c2}(2P)$ are consistent with experimental values of $X(3915)$ and $Z(3930)$, respectively. Besides, giving the mass spectrum analysis to support $X(3915)$ as $χ_{c0}(2P)$, we also calculate the width of $χ_{c0}(2P)$ with the same framework, which is also consistent with the experimental data of $X(3915)$. Thus, the possibility of charmoniumlike state $X(3915)$ as $χ_{c0}(2P)$ state is further enforced.

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arXiv2020

Are the $Y$ states around 4.6 GeV from $e^+e^-$ annihilation higher charmonia?

In this work, we present the mass spectrum of higher charomona around and above 4.6 GeV by adopting the unquenched potential model. We perform a combined fit to the updated experimental data of $e^+e^- \to ψ(2S)π^+π^-$ and $e^+e^-\to Λ_c\barΛ_c$. To understand the "platform" structure observed in the range of $4.57 \sim 4.60$ GeV existing in the $Λ_c\barΛ_c$ invariant mass spectrum of $e^+e^-\to Λ_c\barΛ_c$ of BESIII, we introduce two resonances in this combined fit to the $e^+e^- \to ψ(2S)π^+π^-$ and $e^+e^-\to Λ_c\barΛ_c$, which have resonance parameters, $m_{Y_1}=4585\pm2$ MeV, $Γ_{Y_1}=29.8\pm8.0$ MeV, $m_{Y_2}=4676\pm7$ MeV, and $Γ_{Y_2}=85.7\pm15.0$ MeV. Furthermore, combining with our theoretical results, we indicate that the two charmonium-like $Y$ states can be due to two higher charmonia, which are mixtures of $6S$ and $5D$ $c\bar{c}$ states. Their two-body open-charm decay behaviors are given. Under the same framework, our analysis of the data of $e^+e^-\to D_{s}^+D_{s1}(2536)^-$ recently released by Belle supports to introduce these two higher charmonia around 4.6 GeV. Additionally, we predict the masses and two-body open-charm decays of six higher charmonia $ψ(nS)$ and $ψ(mD)$ with $n=7,8,9$ and $m=6,7,8$ above 4.6 GeV. Search for these higher charmonia will be an interesting issue for the running BESIII and BelleII, and even the possible Super Tau-Charm Factory discussed in China.

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arXiv2020

Production of $P-$wave charmed and charmed-strange mesons in pion and kaon induced reactions

In the present work, we investigate the production of $P-$wave charmed or charmed-strange mesons in the pion or kaon induced reactions on a proton target. The total cross sections as well as the differential cross sections depending on the scattering angle are evaluated in an effective Lagrangian approach. Our estimations indicate that magnitude of the cross sections strongly depends on the model parameter but such dependence can be almost completely canceled for the cross section ratios. These model independent ratios can be taken as a good criterion of the validity of heavy quark limit in the charmed region, which is helpful to understand $P$-wave charmed and charmed-strange mesons.

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