arXiv subjects

Hong-Ying Jin

Publications and source records attributed to Hong-Ying Jin.

At least 19 recordsLinked to original sources

arXiv2026

Probing Excited $q\bar{q}$ Mesons via QCD Sum Rules

We present a systematic study of the masses of light excited $q\bar{q}$ mesons using QCD sum rules at next-to-leading order (NLO). To probe excited states, we construct several interpolating currents with covariant derivatives inserted. The calculation is carried out up to dimension-8 condensates, including NLO perturbative and $m\langle\bar{q}q\rangle$ corrections. Employing Gaussian sum rules, we obtain several $J^P=2^\pm$ nonets with masses that agree well with experiments. Several $J=0,1$ states compatible with experiments are also obtained using both Gaussian and Laplace sum rules. In particular, the $J^{PC}=2^{++}$ current couples to two distinct $2^{++}$ resonances. This work demonstrates the efficacy of operators with covariant derivatives for studying excited hadrons.

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arXiv2026

Revising the Mass of Light Hybrid Mesons: NLO QCD Sum Rules Point to $ϕ(2170)$ as a Prime Candidate

We present a comprehensive next-to-leading order (NLO) QCD sum rule analysis for light hybrid mesons with $J^{PC}=1^{--}$, incorporating condensates up to dimension-8 and NLO corrections to the perturbative, gluon condensate, and four-quark condensate contributions. These corrections are found to be substantial and reveal the necessity of contributions beyond leading order. Employing both Laplace (LSR) and Gaussian (GSR) sum rules, our analysis predicts a mass in the conservative range of $2.1-2.4\,\text{GeV}$ for the light $1^{--}$ hybrid. These predictions are significantly lower than previous leading-order (LO) estimates (around $2.9\,\text{GeV}$) and bridge the gap between QCD sum rules and other approaches. Our findings establish the $ϕ(2170)$ resonance as a prime candidate for the light vector hybrid meson.

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arXiv2026

NLO QCD sum rules analysis of $1^{-+}$ tetraquark states

We present a next-to-leading order QCD sum rule analysis of $J^{PC}=1^{-+}$ light tetraquark states. By investigating various compact tetraquark and molecular configurations, we determine the mass spectrum of these states. Our calculations exclude the possibility that $π_{1}(1400)$ is a tetraquark or hybrid-tetraquark mixture. This suggests that it may not exist, which is consistent with recent experimental results. In contrast, we obtained multiple $1^{-+}$ states around $2.0\,\text{GeV}$ that match well with $π_{1}(2015)$, which makes us confident that $π_{1}(2015)$ is a tetraquark candidate. As for $π_{1}(1600)$, our results indicate that the tetraquark currents tend to couple to heavier states, reducing the possibility of it being a tetraquark, while earlier studies suggested the opposite.

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arXiv2025

QCD sum rule analysis of $0^{+}$ four-quark states

We present a comprehensive QCD sum rules analysis at next-to-leading order for all types of $J^P=0^{+}$ four-quark states composed of $u$, $d$, and $s$ quarks. The eigenvectors of the renormalization matrix are chosen to be the renormalized four-quark operators, which can be equally interpreted as tetraquark or molecule operators. Meanwhile, the typical nonet masses given by bare tetraquark operators are lower than those given by bare molecule operators. Most of the nonet masses are around $1-2\text{GeV}$, and they can be interpreted as the $0^+$ mesons observed in experiments. We find a category of four-quark nonets with masses $\lesssim1\text{GeV}$, potentially corresponding to the light $0^+$ mesons $f_0(500)$, $K^*_0(700)$, $f_0(980)$, and $a_0(980)$. On the other hand, the possible 27-fold states are heavier than most of the nonets, with masses $\gtrsim 2\text{GeV}$. The main uncertainty arises from the factorization of high-dimensional condensates, which usually underestimates their values. To address this, we introduce deviation factors for the dimension-6, -8, and -10 condensates, and vary them over a wide range to obtain conservative estimates of the $0^+$ four-quark state masses. Some general properties of the $0^+$ light four-quark states can be derived that do not rely on precise numerical values. We also find that the ambiguity in the factorization of the dimension-8 condensate can introduce a larger discrepancy than previously estimated. As a byproduct, we propose a simple trick for renormalizing multi-quark operators at the one-loop level.

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arXiv2024

The $H\rightarrow b\bar{s}$ decay and its implication for the vector-like singlet fermion model

The vector-like quark model is one of the extensions of the standard model (SM) of particle physics. The simplest version of this model introduces a vector-like singlet quark which can mix with SM quarks and give rise to new contributions to the flavor-changing decays of the Higgs boson. In this work we first present a systematic analysis of the branching ratios of the decays $H\rightarrow b\bar{s}, b\bar{d}$ at leading order in the standard model. Our results show that it is challenging to observe these two modes because of their small branching ratios. Then augmenting the SM with a vector-like singlet top quark, assuming the top partner only mixes with the top quark, complete one-loop contributions are taken into account in the amplitudes. Further results indicate that the branching ratios of the decays $H\rightarrow b\bar{s}, b\bar{d}$ are sensitive to the mass of the top partner $M_{T}$ and the mixing effects characterized by $\sinθ_{L}$. By tuning the values of $M_{T}$ and $\sinθ_{L}$, the branching ratios may rise to a level accessible to LHC experiments. Combined with the branching ratios obtained from a probabilistic model, the allowed areas in the $M_{T}-\sinθ_{L}$ plane are displayed. Tagging efficiencies and feasibility for detecting $H\rightarrow b\bar{s}$ are specifically discussed and we conclude that with large statistics it is promising to discover the $H\rightarrow b\bar{s}$ decay at the LHC.

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arXiv2022

Mass of $1^{-+}$ four-quark--hybrid mixed states

We calculate the masses of $J^{PC}=1^{-+}$ light exotic mesons by QCD sum rules; the masses are extracted from four-quark--hybrid mixing correlation functions. We construct several $1^{-+}$ four-quark currents and hybrid currents, and get two masses around $1.2\text{-}1.4\text{GeV}$ and $1.45\text{-}1.67\text{GeV}$; they can be identified as $π_1(1400)$ and $π_1(1600)$.

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arXiv2022

Mixing of X and Y states from QCD Sum Rules analysis

We study $\bar{Q}Q\bar{q}q$ and $\bar{Q}qQ\bar{q}$ states as mixed states in QCD sum rules. By calculating the two-point correlation functions of pure states of their corresponding currents, we review the mass and coupling constant predictions of $J^{PC}=1^{++}$, $1^{--}$, $1^{-+}$ states. By calculating the two-point mixed correlation functions of $\bar{Q}Q\bar{q}q$ and $\bar{Q}qQ\bar{q}$ currents, and we estimate the mass and coupling constants of the corresponding `"physical state" that couples to both $\bar{Q}Q\bar{q}q$ and $\bar{Q}qQ\bar{q}$ currents. Our results suggest that $1^{++}$ states are more likely mixing from $\bar{Q}Q\bar{q}q$ and $\bar{Q}qQ\bar{q}$ components, while for $1^{--}$ and $1^{-+}$ states, there is less mixing between $\bar{Q}Q\bar{q}q$ and $\bar{Q}qQ\bar{q}$. Our results suggest the $Y$ series of states have more complicated components.

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arXiv2019

Vector and Scalar Mesons' Mixing from QCD Sum Rules

We study $\bar qq$-hybrid mixing for the light vector mesons and $\bar qq$-glueball mixing for the light scalar mesons in Monte-Carlo based QCD Laplace sum rules. By calculating the two-point correlation function of a vector $\bar qγ_μq$ (scalar $\bar q q$) current and a hybrid (glueball) current we are able to estimate the mass and the decay constants of the corresponding mixed "physical state" that couples to both currents. Our results do not support strong quark/gluonic mixing for either the $1^{--}$ or the $0^{++}$ states.

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arXiv2017

The Mass and Decay Properties of the $1^{-+}$ Light Hybrid Meson

We calculate the complete form of the dimension-8 condensate contributions in the two-point correlator of the ($1^{-+}$,$0^{++}$) light hybrid current considering the operator mixing under renormalization. We find the inclusion these higher power corrections as well as the update of $\langle g^3G^3\rangle$ increase the QCD sum rule mass prediction for the $1^{-+}$ light hybrid. The obtained conservative mass range 1.72--2.60 GeV does not favor the $π_1(1400)$ and the $π_1(1600)$ to be pure hybrid states and suggests the $π_1(2015)$ observed by E852 is more likely to have much of a hybrid constituent. We also study the $b_1π$ and $ρπ$ decay patterns of the $1^{-+}$ light hybrid with light-cone QCD sum rules. We obtain a relatively large partial decay width of the $b_1π$ mode, which is consistent with the predictions from the flux tube models and lattice QCD. More interestingly, using the tensor interpolating current we find the partial decay width of the $ρπ$ mode is small due to the absence of the leading twist contribution in the light-cone expansion of the correlation function.

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arXiv2017

Constraint on the light quark mass $m_q$ from QCD Sum Rules in the $I=0$ scalar channel

In this paper, we reanalyze the $I=0$ scalar channel with the improved Monte-Carlo based QCD sum rules, which combines the rigorous Hölder-inequality-determined sum rule window and a two Breit-Wigner type resonances parametrization for the phenomenological spectral density that satisfies the the low-energy theorem for the scalar form factor. Considering the uncertainties of the QCD parameters and the experimental masses and widths of the scalar resonances $σ$ and $f_0(980)$, we obtain a prediction for light quark mass $m_q(2\,\textrm{GeV})$ = $\frac{1}{2}(m_u(2\,\textrm{GeV})$ + $m_d(2\,\textrm{GeV}))$ = $4.7^{+0.8}_{-0.7}\,\textrm{MeV}$, which is consistent with the PDG (Particle Data Group) value and QCD sum rule determinations in the pseudoscalar channel. This agreement provides a consistent framework connecting QCD sum rules and low-energy hadronic physics. We also obtain the decay constants of $σ$ and $f_0(980)$ at 2 GeV, which are approximately $0.64-0.83$ GeV and $0.40-0.48$ GeV respectively.

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arXiv2017

A comprehensive revisit of the $ρ$ meson with improved Monte-Carlo based QCD sum rules

We improve the Monte-Carlo based QCD sum rules by introducing the rigorous Hölder-inequality-determined sum rule window and a Breit-Wigner type parametrization for the phenomenological spectral function. In this improved sum rule analysis methodology, the sum rule analysis window can be determined without any assumptions on OPE convergence or the QCD continuum.Therefore an unbiased prediction can be obtained for the phenomenological parameters (the hadronic mass and width etc.). We test the new approach in the $ρ$ meson channel with re-examination and inclusion of $α_s$ corrections to dimension-4 condensates in the OPE. We obtain results highly consistent with experimental values. We also discuss the possible extension of this method to some other channels.

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arXiv2016

Investigation of the light four-quark states with exotic $J^{PC}=0^{--}$

We study the exotic $J^{PC}=0^{--}$ four-quark states in Laplace sum rules (LSR) and finite energy sum rules (FESR). We use the vector tetraquark-like currents as interpolating currents in the correlator, from which the $1^{+-}$ states are also studied. In the mass extraction, we use the standard stability criterion with respect to the Borel parameters and the QCD continuum thresholds and consider the effect of the violation of factorization in estimating the high dimensional condensates as a source of uncertainties. The obtained mass prediction $1.66\pm0.14$ GeV is much lower than the previous sum rule predictions obtained using the scalar currents. Our result favours the four-quark interpretation of the possible $ρπ$ dominance in the $D^0$ decay. We also discuss the possible decay patterns of these exotic four-quark states.

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arXiv2015

New predictions on the mass of the $1^{-+}$ light hybrid meson from QCD sum rules

We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of $1^{-+}$ light hybrid current $g\bar{q}(x)γ_νiG_{μν}(x)q{(x)}$. With inclusion of these higher-power corrections and updating the input parameters, we re-analyze the mass of the $1^{-+}$ light hybrid meson from Monte-Carlo based QCD sum rules. Considering the possible violation of factorization of higher dimensional condensates and variation of $\langle g^3G^3\rangle$, we obtain a conservative mass range 1.72--2.60\,GeV, which favors $π_{1}(2015)$ as a better hybrid candidate compared with $π_{1}(1600)$ and $π_{1}(1400)$.

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arXiv2014

Search for supersymmetric baryons near production threshold in terms of the superflavor symmetry

The supersymmetry (SUSY) may be one of the most favorable extensions of the standard model (SM), however, so far at LHC no evidence of the SUSY particles were observed. An obvious question is whether they have already emerged, but escaped from our detection, or do not exist at all. We propose that the future ILC may provide sufficient energy to produce SUSY particles if they are not too heavy in the low background environment. The superflavor symmetry associates baryons with mesons as long as both of them containing a heavy constituent and a light one. In this work, we estimate the production rate of SUSY baryons near their production threshold in terms of the $B\bar B$ production data. Our analysis indicates that if the SUSY baryons with masses below $\sqrt s/2$ ($\sqrt s$ is the ILC energy) exist, they could be observed at future ILC.

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arXiv2006

Study on the Form Factors at Effective Vertices of Diqarks Interacting with Gauge Bosons

The diquark structure in baryons is commonly accepted as a reasonable approximation which can much simplify the picture and reduce the length of calculations. However, a diquark by no means is a point-like particle, even though it is treated as a whole object. Therefore, to apply the diquark picture to the phenomenological calculations, at the effective vertices for the diquark-gauge boson interactions, suitable form factors must be introduced to compensate the effects caused by the inner structure of the diquark. It is crucial to derive the appropriate form factors for various interactions. In this work, we use the Bethe-Salpeter equation to derive such form factors and numerically evaluate their magnitudes.

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arXiv2006

Study on Strong Decays of $D_{sJ}(2632)$

The resonance $D_{sJ}(2632)$ observed by SELEX, has attracted great interests and meanwhile brought up serious dispute. Its spin-parity, so far has not finally determined and if it exists, its quark-structure might be exotic. Following the previous literature where $D_{sJ}(2632)$ is assumed to be a radial-excited state of $1^-$, we consider the possibilities that it might be a $q\bar q$ ground state of $2^+$ or the first radial-excited state of $0^+$ $D_{sJ}(2317)$ and re-calculate its strong decay widths in terms of the Bethe-Salpeter equation. Our results indicate that there still is a sharp discrepancy between the theoretical evaluation and data.

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arXiv2006

Spectra of Free Diquark in the Bethe-Salpeter Approach

In this work, we employ the Bethe-Salpeter (B-S) equation to investigate the spectra of free diquarks and their B-S wave functions. We find that the B-S approach can be consistently applied to study the diqaurks with two heavy quarks or one heavy and one light quarks, but for two light-quark systems, the results are not reliable. There are a few free parameters in the whole scenario which can only be fixed phenomenologically. Thus, to determine them, one has to study baryons which are composed of quarks and diquarks.

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arXiv2005

Note on the Slope Parameter of the Baryonic Λ_b to Λ_c Isgur-Wise Function

Using the framework of the Heavy Quark Effective Theory we have re-analyzed the Isgur-Wise function describing semileptonic Λ_b to Λ_c decays in the QCD sum rule approach. The slope parameter of the Isgur-Wise function is found to be ρ^2 = 1.35 \pm 0.12, which is consistent with an experimental measurement and a lattice calculation. To O(1/m_b,1/m_c) of the heavy quark expansion the integrated Λ_b decay width is used to extract the CKM matrix element V_{cb} for which we obtain a value of |V_{cb}| = 0.041 \pm 0.004 in excellent agreement with the value of |V_{cb}| determined from semileptonic B to D^* decays.

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