arXiv subjects

Jin-Zhong Han

Publications and source records attributed to Jin-Zhong Han.

6 recordsLinked to original sources

arXiv2026

Quarkonium light-cone distribution amplitudes: twist structure and mass dependence

We present a systematic study of the leading- and next-to-leading-twist light-cone distribution amplitudes (LCDAs) of ground-state pseudoscalar and vector quarkonium within the light-front quark model (LFQM). By implementing the replacement $M \to M_0$, we analyze the longitudinal and transverse structures of the LCDAs, together with their Gegenbauer moments, $ξ$-moments, and transverse momentum moments. We show that charge-conjugation symmetry enforces the exact vanishing of all odd Gegenbauer moments and odd $ξ$-moments. For pseudoscalar quarkonium, the twist-2 and twist-3 LCDAs become identical, which leads to the same Gegenbauer moments, $ξ$-moments, and transverse momentum moments. For vector quarkonium, although the twist-2 and twist-3 LCDAs differ in the case of finite quark masses, they progressively converge as the quark mass increases. In the heavy-quark limit, all quarkonium LCDAs satisfy $ϕ^A_{2} = ϕ^P_{3} \simeq ϕ^{\parallel}_{2} \simeq ϕ^{\perp}_{3}$, demonstrating an emergent twist-independence of quarkonium distribution amplitudes. We further find that the LCDAs become increasingly peaked and narrower with increasing quark mass, indicating that the meson system becomes increasingly close to a nonrelativistic bound state, with a more uniform and stable distribution of internal longitudinal momentum. For all quarkonium, the peak value exhibits a simple phenomenological scaling behavior governed by the ratio $m/β$. The transverse momentum moments increase with the meson mass, indicating a progressively more compact bound-state structure. These results reveal a universal and systematic evolution of quarkonium LCDAs driven by the quark mass.

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arXiv2025

Searching for single production of vectorlike quarks decaying into Wb at a future muon-proton collider

This work investigates the discovery potential for singly produced vectorlike quarks~(VLQs) $T$ ($Q=+2/3e$) and $Y$ ($Q=-4/3e$) decaying to $Wb$ at future $μp$ colliders with $\sqrt{s}=5.29$, 6.48, and 9.16 TeV, analyzing both leptonic and hadronic $W$ decay channels through detailed detector simulations. The hadronic channel demonstrates superior sensitivity, enabling $5σ$ discovery up to $m_T=3750$ GeV ($m_Y=4100$ GeV) at 9.16 TeV with 100 fb$^{-1}$, while exclusion limits reach $m_T=4500$ GeV ($g^*\geq0.06$) and $m_Y=4800$ GeV ($κ_Y\geq0.04$) - significantly beyond LHC capabilities. At 5.29 TeV, discovery regions cover $g^*\in[0.15,0.5]$ for $m_T\in[1500,2520]$ GeV and $κ_Y\in[0.12,0.5]$ for $m_Y\in[1700,2700]$ GeV, with exclusions extending to $m_T=2750$ GeV and $m_Y=3020$ GeV. These results, obtained within a simplified two-parameter framework ($m_{T/Y}$ and electroweak couplings $g^{\ast}$), establish $μp$ colliders as uniquely powerful tools for probing high-mass VLQ states, particularly in the boosted jet regime.

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arXiv2024

Pair production of the singlet vector-like B quark at the CLIC

Vector-like quarks~(VLQs) are a common feature of many scenarios of new physics beyond the Standard Model~(SM), which generally decay into a SM third-generation quark with a SM gauge boson, or a Higgs boson. The presence of a new exotic decay mode of VLQs will reduce the branching ratios of these standard decay modes and thus relax the current mass exclusion limits from LHC experiments. Based on a model-independent framework, we investigate the prospect of discovering the pair production of the weak-singlet VLQ-$B$ at the future 3-TeV Compact Linear Collider~(CLIC), by focusing on the final states including one $Z$ boson and four $b$-jets via two types of modes: $Z\to \ell^{+}\ell^{-}$ and $Z\to ν\barν$. By performing a rapid detector simulation of the signal and background events, and considering the initial state radiation and beamstrahlung effects, the exclusion limit at the 95\% confidence level and the $5σ$ discovery prospects are respectively obtained on the branching ratio of $B\to bZ$ and the VLQ-$B$ masses at the future 3-TeV CLIC with an integrated luminosity of 5 ab$^{-1}$.

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arXiv2022

Search for single production of vectorlike $B$-quarks at the LHC

New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model, which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider~(LHC). Based on a model-independent framework, we propose to search for the vectorlike $B$-quark~(VLQ-$B$) and focus on resonant production via $b$-gluon fusion through chromomagnetic interactions. We then explore the possible signals of the VLQ-$B$ through the $B\to tW$ decay mode at the 14 TeV LHC. After a rapid simulation of signal and background events, the $2σ$ excluded regions and the $5σ$ discovery reach in the parameter plane of $κ_{B}-M_B$ are obtained at the LHC with an integrated luminosity of 300~(3000) fb$^{-1}$ in the dilepton final states.

hep-ph↗

arXiv2021

Single production of vectorlike $B$ quarks at the CLIC

The vector-like quarks are predicted in many new physics scenarios beyond the Standard Model~(SM) and could be seen potential signatures of new physics at the TeV energy scale. In this work, we study single production of exotic singlet and doublet vectorlike bottom quarks (VLQ-$B$) at future Compact Linear Collider~(CLIC) via the process $e^{+}e^{-}\to B\bar{b}$ with the decay channel $B\to bZ$ and two types of modes: $Z\to \ell^{+}\ell^{-}$ and $Z\to ν\barν$. We calculate the cross sections of signal and relevant SM backgrounds. After a fast simulation of the signal and background events, the exclusion limit at 95\% confidence level and $5σ$ discovery prospects on the parameters (the coupling strength $κ_{B}$ and the VLQ-$B$ mass) have been, respectively, presented at the future CLIC with centre of mass energy $\sqrt{s}=3$ TeV and integrated luminosity of 5~ab$^{-1}$.

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arXiv2017

The $B-L$ Scotogenic Models for Dirac Neutrino Masses

We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of $U(1)_{B-L}$ extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by anomaly free condition and the new particles may have exotic $B-L$ charges so that the direct SM Yukawa mass term $\barν_Lν_R\overline{ϕ^0}$ and the Majorana mass term $(m_N/2)\overline{ν_R^C}ν_R$ are naturally forbidden. After the spontaneous breaking of $U(1)_{B-L}$ symmetry, the discrete $Z_{2}$ or $Z_{3}$ symmetry appears as the residual symmetry and give rise to the stability of intermediated fields as DM candidate. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed.

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