arXiv subjects

Jingya Zhu

Publications and source records attributed to Jingya Zhu.

At least 19 recordsLinked to original sources

arXiv2026

Assessing Parameter Redundancy in Transformers for Jet Tagging

Transformer-based jet taggers, such as the Particle Transformer (ParT) and the More-Interaction Particle Transformer (MIParT), achieve excellent discrimination by exploiting correlations among jet constituents, but often require more trainable parameters than earlier deep-learning taggers. In this paper, we investigate whether comparable discriminating power can be achieved with substantially fewer parameters. We introduce an hourglass structure that replaces the feed-forward networks (FFNs) in the attention blocks while leaving the particle-interaction attention unchanged. We also introduce a lightweight particle-embedding layer to replace the original dense embedding network. Applying both modifications to ParT and MIParT yields the hourglass (HG) variants ParT-HG and MIParT-HG, respectively. We evaluate both models on benchmark datasets for top tagging and quark-gluon discrimination. Both variants retain comparable tagging performance, including background rejection at fixed signal efficiencies, while using only approximately 48% and 39.7% of the parameters of their respective baselines. On the larger JetClass dataset, accuracy and AUC decrease by less than 1%, and background rejection also decreases for several signal classes. Overall, our approach provides an alternative way to reduce the parameter count of Transformer jet taggers while largely retaining their tagging performance.

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arXiv2026

Symmetry Analysis of Compact Tetraquark States and Implications for the Fully Charmed Candidates $X(6600)$, $X(6900)$, and $X(7100)$

Motivated by recent experimental observations, we investigate the $J^P$ distribution of low-energy compact tetraquark states using symmetry analysis based on inherent nodal structures. Assuming tetrahedral and square configurations for the $qq\bar q\bar q$ system, we derive the allowed orbital structures from the restricted representations of $S_4$ onto $S_2\times S_2$ for $L\leq3$. The accessible-state distribution is particularly prominent in the $J^P=2^+$, $2^-$, and $3^-$ sectors, with the $2^+$ sector showing the strongest low-energy preference. We further find that the symmetry-driven distribution is qualitatively similar to that of the three-flavor four-quark system, and that the dominant $J^P=2^+$ pattern persists under phenomenological weightings inspired by chromomagnetic interaction (CMI) considerations. These results suggest that the low-lying compact tetraquark spectrum is primarily constrained by symmetry, while the detailed distribution exhibits sensitivity to dynamical weightings. Applying this framework to the fully charmed candidates $X(6600)$, $X(6900)$, and $X(7100)$, we find that their observed $J^{PC}=2^{++}$ quantum numbers are consistent with a low-lying compact tetraquark interpretation. The present analysis identifies the relative ordering of the $1^-$ and $1^+$ states as a sensitive channel, suggesting a direction for future non-perturbative investigations.

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arXiv2025

Particle-level transformers for 95 GeV Higgs boson searches at future $e^+e^-$ Higgs factories

Motivated by several mild excesses around 95~GeV, we investigate the prospects for a light scalar $S$ produced via Higgsstrahlung, $e^+e^- \to Z(\mu^+\mu^-)S$, at future $e^+e^-$ Higgs factories. We take the CEPC as a benchmark, with a center-of-mass energy of $\sqrt{s}=240$ GeV and an integrated luminosity of $L=20~\mathrm{ab}^{-1}$. We focus on the decay modes $S\to\tau^+\tau^-$ and $S\to b\bar b$. To maximize sensitivity, we employ the particle-level transformer networks Particle Transformer (ParT) and its more-interactive variant MIParT, which exploit the features of all reconstructed objects and their correlations. For a representative signal benchmark, this approach improves the expected statistical precision on the signal strength by factors of 2.3 in the $\tau^+\tau^-$ channel and 1.4 in the $b\bar b$ channel compared to a cut-based analysis. Within the flipped Next-to-Two-Higgs-Doublet Model (N2HDM-F), the CEPC can measure the signal strength with a statistical precision down to 1.0% in the $\tau^+\tau^-$ channel and 0.69% in the $b\bar b$ channel using MIParT. It can achieve a $5\sigma$ discovery for $\mu_{\tau\tau}^{ZS}>1.6\times10^{-2}$ or $\mu_{bb}^{ZS}>5.0\times10^{-3}$, and reach 1% precision for $\mu_{\tau\tau}^{ZS}>0.93$ or $\mu_{bb}^{ZS}>0.14$. These gains are expected to qualitatively carry over to other future lepton colliders such as FCC-ee and the ILC. Our results demonstrate the potential of particle-level machine-learning techniques to strengthen light Higgs searches at future $e^+e^-$ Higgs factories.

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arXiv2025

An analysis on doubly bottom molecular tetraquarks composed of $H_{(s)}$ and $T_{(s)}$ doublets

In this work, we investigate the doubly bottom $H_{(s)}\bar{T}_{(s)}$ and $H_{(s)}T_{(s)}$ systems by adopting the one-boson-exchange model, where $H_{(s)}$ and $T_{(s)}$ represent $S$-wave $B^{(*)}_{(s)}$ and $P$-wave $B^{(*)}_{(s)1,2}$ doublets, respectively. For the $H\bar{T}$ systems, we predict some loosely bound states in the $I(J^{PC})=0(1^{-\pm})$ $B\bar{B}_{1}$, $I(J^{PC})=0(2^{-\pm})$ $B\bar{B}_{2}^{*}$, $I(J^{PC})=0(1^{-\pm})$ $B^*\bar{B}_{1}$ and $I(J^{PC})=0(2^{-\pm})$ $B^*\bar{B}_{2}^{*}$ channels, which are the most promising hidden bottom molecular tetraquarks. For the $HT$ systems, the $B^*B_1$ channels with quantum numbers $I(J^P) = 0(1^{-}), 0(2^{-})$ and the $B^*B_2^*$ channels with $I(J^P) = 0(2^{-})$ are also likely candidates for forming molecular tetraquarks. In contrast, no molecular candidates have been identified in the bottom-strange sectors. One can hope that our predictions will provide valuable insights to the LHCb and Belle II Collaborations as they continue to explore this fascinating field through experimental research.

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arXiv2025

Testing a 95 GeV Scalar at the CEPC with Machine Learning

Several possible excesses around 95 GeV hint at an additional light scalar beyond the Standard Model. We examine the capability of the CEPC to test this hypothesis in the Higgsstrahlung channel $e^{+}e^{-} \to ZS$ with $Z \to\mu^{+}\mu^{-}$ and $S\to\tau^{+}\tau^{-}$. Full detector simulation shows that the optimal center-of-mass energy to study the 95 GeV light scalar is 210 GeV. A deep neural network classifier reduces the luminosity required for discovery by half. At $L = 20~\mathrm{ab}^{-1}$, the CEPC's $5\sigma$ sensitivity to the signal strength $\mu_{\tau\tau}^{ZS}$ reaches 0.016 and 0.020 for $\sqrt{s} =$ 210 GeV and 240 GeV, respectively. The corresponding thresholds for a 5% precision measurement are $\mu_{\tau\tau}^{ZS} > 0.10$ and $>0.12$. At $\sqrt{s}=$ 210 GeV (240 GeV), $5\sigma$ coverage of all N2HDM-Flipped samples with $\chi^2_{h_{95}}<7.82$ requires $L=800\ \mathrm{fb}^{-1}$ (1.22 $\mathrm{ab}^{-1}$). These results establish a 210 GeV run, augmented by machine-learning selection, as the most efficient strategy to confirm or refute the 95 GeV excess at future lepton colliders.

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arXiv2025

The LHC sensitivity to weak gauginos in light of the latest muon $g-2$ and dark matter results

Among the electroweakinos, the weak gauginos have the largest production rate at the LHC and should therefore be the primary focus of searches. In this work, we examine the LHC sensitivity to weak gauginos in light of the latest constraints from the muon $g-2$ anomaly and dark matter (DM) observations. To simultaneously account for the observed $5σ$ deviation in muon $g-2$ and the correct DM relic abundance, the DM candidate in the MSSM must be bino-like: wino- or higgsino-like neutralinos require TeV-scale masses to avoid underabundance, rendering the electroweakino spectrum too heavy to yield a sizable $g-2$ contribution. Moreover, tight direct detection limits disfavor light higgsinos, which can induce sizable DM-nucleon scattering via bino-higgsino mixing. We thus focus on scenarios with a bino-like LSP and relatively heavy higgsinos. Two classes of wino spectra are considered: a light-wino scenario (LWo) with $m_{\tilde{W}} \lesssim 1$~TeV, and a heavy-wino scenario (HWo) with $m_{\tilde{W}} \gtrsim 1$~TeV. For each, we delineate the viable parameter space under current constraints and assess the discovery potential at future LHC stages. We find that while the high-luminosity LHC (HL-LHC) can probe a portion of the parameter space, the high-energy 27~TeV LHC (HE-LHC) is capable of covering most of it.

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arXiv2025

Revisiting CMSSM with Non-Universal Gaugino Masses under Current Constraints

To address the longstanding tension between the Constrained Minimal Supersymmetric Standard Model (CMSSM) and recent experimental data, we investigate non-universal gaugino masses within an SU(5) Grand Unified Theory (GUT) framework, focusing on the $\tilde{g}$-SUGRA scenario where $\lvert M_{3} \rvert \gg \lvert M_{1} \rvert, \lvert M_{2} \rvert$. This hierarchy enables a heavier gluino, thereby evading current experimental bounds on supersymmetric particles. Our analysis reveals that precise Higgs measurements place stringent constraints on the model, requiring $\tanβ\gtrsim 5$ and $ M_{0} \gtrsim 20 \, \tanβ\,\text{GeV}$. Although the $\tilde{g}$-SUGRA scenario can help reconcile the persistent $(g-2)_μ$ anomaly, the Higgs constraints significantly restrict its parameter space, making a large contribution to $(g-2)_μ$ challenging. We also assess the discovery prospects in upcoming dark matter direct detection experiments, including PandaX-xT (200 t.y.), LZ (projected), and XENONnT (20 t.y.), which may not fully cover the viable parameter space. In contrast, future collider experiments$-$such as the High-Luminosity LHC at $3\,\mathrm{ab}^{-1}$ and $\mathrm{CLIC}_{1500}$ at $2.5\,\mathrm{ab}^{-1}$$-$can comprehensively probe the remaining regions. These findings highlight $\tilde{g}$-SUGRA as a promising solution to the CMSSM tension and offer clear, testable predictions for upcoming collider searches.

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arXiv2024

Probing Type-I 2HDM light Higgs in the top-pair-associated diphoton channel

Motivated by the possible 95 GeV diphoton excess, we investigate the capability of the Type-I Two-Higgs-Doublet Model (2HDM-I) to explain this signal under current theoretical and experimental constraints. Using full Monte Carlo (MC) simulations for the process of $pp \to t(\to W^+ b)\bar{t}(\to W^- \bar{b})h(\to \gamma\gamma)$, we evaluate the discovery potential of a 95 GeV Higgs boson at future colliders. Direct Higgs searches strongly constrain the parameter $\alpha$, excluding the region with $\alpha \lesssim 0.95$. Monte Carlo results indicate that a minimum cross section of 0.3 fb is required to achieve a $5\sigma$ signal statistical significance at the HL-LHC with $L = 3~\mathrm{ab}^{-1}$. For the same luminosity, HE-LHC and FCC-hh require 0.67 fb and 2.36 fb, respectively. At the 14 TeV HL-LHC with an integrated luminosity of $3~\mathrm{ab}^{-1}$, parameter regions with $\sin(\beta-\alpha) \gtrsim 0.4$ and $\sin(\beta-\alpha) \gtrsim 0.25$ can be probed at the $5\sigma$ and $2\sigma$ significance levels, respectively. At the 27 TeV HE-LHC with $L = 10~\mathrm{ab}^{-1}$, the sensitivity improves to $\sin(\beta-\alpha) \gtrsim 0.25$ ($5\sigma$) and $\gtrsim 0.15$ ($2\sigma$). For the 100 TeV FCC-hh with $L = 30~\mathrm{ab}^{-1}$, even regions with $\sin(\beta-\alpha) \gtrsim 0.1$ or $\sin(\beta-\alpha) \lesssim -0.05$ can be covered at the $5\sigma$ level. Parameter regions near $\sin(\beta-\alpha) \approx 0$ remain challenging to probe in the diphoton channel, even with increased energy or luminosity.

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arXiv2024

Jet Tagging with More-Interaction Particle Transformer

In this study, we introduce the More-Interaction Particle Transformer (MIParT), a novel deep learning neural network designed for jet tagging. This framework incorporates our own design, the More-Interaction Attention (MIA) mechanism, which increases the dimensionality of particle interaction embeddings. We tested MIParT using the top tagging and quark-gluon datasets. Our results show that MIParT not only matches the accuracy and AUC of LorentzNet and a series of Lorentz-equivariant methods, but also significantly outperforms the ParT model in background rejection. Specifically, it improves background rejection by approximately 25% at a 30% signal efficiency on the top tagging dataset and by 3% on the quark-gluon dataset. Additionally, MIParT requires only 30% of the parameters and 53% of the computational complexity needed by ParT, proving that high performance can be achieved with reduced model complexity. For very large datasets, we double the dimension of particle embeddings, referring to this variant as MIParT-Large (MIParT-L). We find that MIParT-L can further capitalize on the knowledge from large datasets. From a model pre-trained on the 100M JetClass dataset, the background rejection performance of the fine-tuned MIParT-L improved by 39% on the top tagging dataset and by 6% on the quark-gluon dataset, surpassing that of the fine-tuned ParT. Specifically, the background rejection of fine-tuned MIParT-L improved by an additional 2% compared to the fine-tuned ParT. The results suggest that MIParT has the potential to advance efficiency benchmarks for jet tagging and event identification in particle physics. The code is available at the following GitHub repository: https://github.com/USST-HEP/MIParT

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arXiv2024

Investigating higgsino dark matter in the semi-constrained NMSSM

In this study, we explore the characteristics of higgsino-dominated dark matter (DM) within the semi-constrained Next-to-Minimal Supersymmetric Standard Model (scNMSSM), covering a mass range from hundreds of GeV to several TeV. We carefully analyzed the parameter space under existing theoretical and experimental constraints to confirm the viability of higgsino-dominated lightest supersymmetric particles (LSPs) with masses between 100 GeV and 4 TeV. Our study examines various DM annihilation mechanisms, emphasizing the significant role of coannihilation with the next-to-lightest supersymmetric particle (NLSP), which includes other higgsino-dominated particles such as $\tildeχ^{0}_2$ and $\tildeχ^{\pm}_1$. We categorize the annihilation processes into three main classes: $\tildeχ_1^{\pm}$ coannihilation, Higgs funnel annihilation, and $\tildeτ_1$ coannihilation, each combines interactions with $\tildeχ_1^{\pm}$. Our results indicate that achieving the correct relic density in heavier higgsino LSPs requires a combination of coannihilation and Higgs funnel mechanisms. We also assess the potential of future experiments, such as XENONnT, LUX-ZEPLIN (LZ), PandaX-xT, and the Cherenkov Telescope Array (CTA), to probe these DM scenarios through direct and indirect detection. In particular, future spin-independent DM detection can cover all samples with the correct DM relic density for $μ\gtrsim 1300$ GeV. Furthermore, future colliders like the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are found to exceed the detection capabilities of current hadron colliders, especially for higher mass NLSPs. Notably, CLIC at 3000 GeV is anticipated to thoroughly investigate all samples with insufficient DM relic density for $μ\lesssim 1300$ GeV.

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arXiv2024

95 GeV light Higgs in the top-pair-associated diphoton channel at the LHC in the minimal dilaton model

Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we explore the feasibility of detecting a 95 GeV light Higgs boson decaying into a diphoton within the minimal dilaton model at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle $\sinθ_S$. Subsequently, we utilize Monte Carlo simulations to generate the signal of the light Higgs boson via the $pp \to t\bar{t}(s\to γγ)$ process, along with the corresponding backgrounds. To effectively separate the signal from the dominant backgrounds $ttγγ$, we employ a meticulous cut-based selection process. Ultimately, we find that with an integrated luminosity of $L = 3000 {{~\rm fb}^{-1}}$, the regions of $|\sinθ_S|>0.2$ can be covered over the $3σ$ level.

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arXiv2024

Exploring Heavy Higgs Bosons at a 100 TeV Hadron Collider within the Semi-Constrained NMSSM

In this study, we explore the detectability of heavy Higgs bosons in the $pp \to b\bar{b}H/A \to b\bar{b}t\bar{t}$ channel at a 100 TeV hadron collider within the semi-constrained Next-to-Minimal Supersymmetric Standard Model (NMSSM). We calculate their production cross sections and decay branching ratios, comparing these with simulation results from existing reference. We focus on the heavy, doublet-dominated CP-even Higgs $H$ and CP-odd Higgs $A$, with mass limits set below 10 TeV to ensure detectability. We find that at a collider with 3 ab$^{-1}$ of integrated luminosity, the potential for detecting heavy Higgs bosons varies significantly with their mass and $\tanβ$. Heavy Higgs bosons below 2 TeV are within the testable range, while those heavier than 7 TeV fall below the exclusion and discovery thresholds, rendering them undetectable. For masses between 2 and 7 TeV, heavy Higgs bosons with $\tanβ$ less than 20 can be detected, whereas those with $\tanβ$ greater than 20 are beyond the current discovery or exclusion capabilities.

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arXiv2023

Smuon contribution to muon g-2 in Grand Unified supersymmetric theories

In GUT-scale constrained (GUTc) supersymmetric (SUSY) models, the mass of smuon $\tildeμ_1$ is typically heavier than that of stau $\tildeτ_1$, and stau co-annihilation is a typical annihilation mechanism of dark matter. However, light smuon is more favored by the muon $g-2$ anomaly, thus smuon-neutralino loop contribution to muon $g-2$ is usually smaller than that of sneutrino-chargino. Inspired by the latest muon $g-2$ results, we take the GUTc- Next-to-Minimal Supersymmetric Model (NMSSM) as an example, where the gaugino (Higgs) masses are not unified to the usual parameter $M_{1/2}$ ($M_0$), exploring its possibility of light smuon and its contribution to muon $g-2$. After complicated calculations and discussions, we conclude that in GUTc-NMSSM the smuon can be lighter than stau. In this light-smuon scenario, the contribution of smuon-neutralino loop to the muon $g-2$ can be larger than that of the sneutrino-chargino loop. The annihilation mechanisms of dark matter are dominated by multiple slepton or chargino co-annihilation. In our calculations, we consider also other latest related constraints like Higgs data, SUSY searches, dark matter relic density and direct detections, etc.

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arXiv2023

Light dark matter confronted with the 95 GeV diphoton excess

The correlation between Higgs-like scalars and light dark matter is an interesting topic, especially now that a $125 GeV$ Higgs was discovered and dark matter (DM) searches got negative results. The $95 GeV$ excess reported by the CMS collaboration with $132 fb^{-1}$ data recently, and the DM search results by XENONnT and LZ collaborations motivate us to revise that. In this work, we study that in the GUT-scale constrained (GUTc) Next-to-Minimal Supersymmetric Model (NMSSM), where most parameters are input at the GUT scale, but with scalar and gaugino masses not unified there. In the calculation we also consider other recent experimental constraints, such as Higgs data, Supersymmetry (SUSY) searches, DM relic density, etc. After detailed analysis and discussion, we find that: (i) The light DM can be bino- or singlino-dominated, but can be mixed with minor components of Higgsino. (ii) Both cases can get right relic density and sizable Higgs invisible decay, by adjusting the dimensionless parameters $λ, κ$, or suitably mixing with Higgsino. (iii) Both cases can have four funnel annihilation mechanisms, i.e., annihilating through $Z, a_1, h_2, h_1$. (iv) Samples with right relic density usually get weak signal of Higgs invisible decay at future lepton collider, but the $95 GeV$ scalar can have sizable $b\bar{b}$ signal.

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arXiv2023

Light Higgs boson in the NMSSM confronted with the CMS diphoton and ditau excesses

In 2018, the CMS collaboration reported a di-photon excess around 95.3 GeV with a local significance of 2.8 $σ$. Interestingly, the CMS collaboration also reported a di-tau excess recently at 95 $\sim$ 100 GeV with a local significance of 2.6 $\sim$ 3.1 $σ$. Besides, a $b\bar{b}$ excess at 98 GeV with a 2.3 $σ$ local significance was reported with LEP data about twenty years ago. In this work, we consider interpreting these excesses together with a light Higgs boson in the next-to-minimal supersymmetric standard model (NMSSM). We conclude that in NMSSM the 95 $\sim$ 100 GeV excesses are difficult to be satisfied simultaneously (not possible globally at $1σ$ level, or simultaneously at $2σ$ level), and we analyze two partial-satisfied scenarios: the globally $2σ$ scenario and small di-photon scenario. An approximate equation of global fit to the three excesses is derived, and two representative types of surviving samples are analyzed in detail. Since the mass regions of these excesses are near the Z boson, we also consider checking the light Higgs boson in the $t\bar{t}$-associated channels. The detailed results may be useful for further checking the low-mass-region excesses in the future.

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arXiv2023

Light higgsino scenario confronted with muon g-2

Light higgsinos below several hundred GeV are favored or required by the naturalness of low energy supersymmetry. If only higgsinos are light while other sparticles are sufficiently heavy, we have the so-called light higgsino scenario. Confronted with the muon $g-2$ data, this scenario is examined in this work. Since in this scenario the LSP (lightest sparticle) is higgsino-like, we need to also consider the dark matter constraints. Assuming a light higgsino mass parameter $μ$ in the range of 100-400 GeV while gaugino mass parameters above TeV, we explore the parameter space under the muon $g-2$ data and the dark matter constraints. We find that, to explain the muon $g-2$ anomaly at $2σ$, the winos and sleptons are respectively upper bounded by 3 TeV and 800 GeV. In this case, we find that the light higgsino-like dark matter can sizably scatter with nucleon and thus the allowed parameter space can be covered almost fully by the future LZ dark matter detection project. We also perform a Monte Carlo simulation to figure out the potential of HL-LHC to detect the light sleptons in this scenario. It turns out that compared with the current LHC limits, the HL-LHC can further cover a part of the parameter space.

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arXiv2022

The possible assignments of the scalar $K_0^(1950)$ and $K_0^(2130)$ within the $^3P_0$ model

We have evaluated the strong decays of the $K_0^*(1950)$ and $K_0^*(2130)$ within the $^3P_0$ model, by employing the meson wave functions from the relativized quark model. By comparing with the experimental measurements, the $K_0^*(2130)$ could be assigned as $K_0^*(3^3P_0)$, while the $K_0^*(1950)$ seems like an exotic state, because its width can not be reasonably reproduced within the $^3P_0$ model. We also predict that the $K_0^*(2^3P_0)$ state has a mass of about $1811$ MeV and a width of about $656$ MeV, while the $K_0^*(4^3P_0)$ state has a mass of about $2404$ MeV and a width of about $180$ MeV.

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arXiv2022

Canonical interpretation of the $D_{s0}(2590)^{+}$ resonance

The $D_{s0}(2590)^{+}$ resonance observed by LHCb Collaboration is a strong candidate of the $D_{s}(2^1S_0)$ state according to its spin parity and strong decay mode. However, the measured mass seems relatively lower than the previous theoretical predictions, which interests the coupled channel interpretations in the literature. In this work, we adopt an alternate approach, taking into account the screening effects in the potential model, to describe the $D_{s0}(2590)^{+}$ resonance. The mass spectrum and strong decays of the excited charmed-strange mesons are investigated within the modified relativized quark model and $^3P_0$ model. The calculated mass and width of the $D_{s0}(2590)^{+}$ are consistent with the experimental observations, which indicate that it can be reasonably interpreted as the $D_{s}(2^{1}S_{0})$ state.

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