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Li Gang

Publications and source records attributed to Li Gang.

At least 19 recordsLinked to original sources

Handwritten Digit Recognition: An Ensemble-Based Approach for Superior Performance

Handwritten digit recognition remains a fundamental challenge in computer vision, with applications ranging from postal code reading to document digitization. This paper presents an ensemble-based approach that combines Convolutional Neural Networks (CNNs) with traditional machine learning techniques to improve recognition accuracy and robustness. We evaluate our method on the MNIST dataset, comprising 70,000 handwritten digit images. Our hybrid model, which uses CNNs for feature extraction and Support Vector Machines (SVMs) for classification, achieves an accuracy of 99.30%. We also explore the effectiveness of data augmentation and various ensemble techniques in enhancing model performance. Our results demonstrate that this approach not only achieves high accuracy but also shows improved generalization across diverse handwriting styles. The findings contribute to the development of more reliable handwritten digit recognition systems and highlight the potential of combining deep learning with traditional machine learning methods in pattern recognition tasks.

cs.CV

Searches for dark matter via charged Higgs pair production in the Inert Doublet Model at $\gamma\gamma$ collider

The Inert Doublet Model(IDM) is one of the simplest extensions beyond Standard Model(SM) with an extended scalar sector, which provide a scalar dark matter particle candidate. In this paper, we investigate the double charged Higgs production at $\gamma\gamma$ collider. By scanning the whole parameter space, we obtain the parameter points corresponding to the correct relic abundance of dark matter. After applying all theoretical and experimental constraints, the parameter space for the existence of dark matter is extremely restricted. We perform the analysis for the signal of $H^+H^-$ production in the IDM and the SM backgrounds, and the optimized selection conditions are chosen in kinematic variables to maximize signal significance. Comparing signal with backgrounds, we obtain the parameter points which can be detected at future $\gamma\gamma$ collider experiments.

hep-ph

Probing the charm-Higgs Yukawa coupling via Higgs boson decay to $h_c$ plus a photon

In this paper, we investigate the decay of Higgs boson to $h_c$ plus a photon in the NRQCD theoretical framework. Comparing with the Higgs decay to $J/\psi$ plus a photon channel, this process has not indirect contribution, can be used to detect the Yukawa coupling of Higgs and charm quarks. The results show that the decay branch ratio of this process is about $10^{-8}$. If we takes into account the $10^{-3}$ efficiency in the $h_c$ detection, no events will be available even in the case of $30ab^{-1}$ luminosity at FCC-pp with 100 TeV center of mass energy. However, if the detection efficiency of $h_c$ is greatly improved in the future, this process will play an important role at linear $e^+e^-$ future colliders and at LHCb. Moreover, this process should be also play an important role when the anomalous charm Yukawa couplings are larger and direct sensitivity.

hep-ph

Photoproduction of the double $J/ψ$ ($Υ$) at the LHC with forward proton tagging

We calculate the photoproduction of double $J/ψ$ ($Υ$) to leading order based on the nonrelativistic quantum chromodynamics factorization framework at the Large Hadron Collider with forward proton tagging. The numerical results of double $J/ψ$ photoproduction pp $\rightarrow$ p$γ$p $\rightarrow$ $J/ψ$ + $J/ψ$ with different forward detector acceptances ($ξ$) are presented. The total cross section of double $J/ψ$ photoproduction is less than 200 fb with 0.1 $<$ $ξ$ $<$ 0.5, but can reach about 1.37(1.27) pb with 0.0015 $<$ $ξ$ $<$ 0.5 ( 0.0015 $<$ $ξ$ $<$ 0.15 ). The double $J/ψ$ photoproduction may have the potential to be detected and provide an interesting signature, thus is useful for studying the mechanism of heavy quarkonium production. We also predict the double $Υ$ photoproduction and find they are, unfortunately, small (with less than 10 fb).

hep-ph

Next-to-leading order QCD corrections to $χ_{cJ} W^+ b$ associated production from top-quark decay

We calculate the next-to-leading order QCD corrections to the excited charmonium $χ_{cJ}$ associated with $ W^+ b $ production from top-quark decay. Our results show that detecting the $χ_{c0}$ production from top-quark decay is very difficult, but the $χ_{c1}$ and $χ_{c2}$ productions have the potential to be detected at the LHC. If the prompt $χ_{cJ}$ production from top-quark decay is really detected at the LHC, it will be useful not only for investigating $J/ψ$ production from top-quark decay but also for understanding the heavy quarkonium production mechanism.

hep-ph

Higher-Order QCD prediction for dark matter pair associated with a b-jet production at the LHC

Dark matter associated visible particle production at high energy colliders provides a unique way to determine the microscopic properties of the dark matter. We investigate a pair of fermionic dark matter particles associated with a b-jet production at the LHC, through a mediator which couples to standard model or dark matter particles via either a vector or axial-vector coupling. The calculation is performed by implementing these simplified models in the FeynRules/MadGraph5 aMC@NLO framework. In our calculation, next-to-leading order QCD corrections and parton-shower effects are considered. We find that this process has a sizeable cross section and the QCD correction can reach more than 2 times than LO results. We also investigate the discovery potential in several benchmark scenarios at the 13TeV LHC.

hep-ph

Next-to-leading order QCD corrections to Higgs boson decay to quarkonium plus a photon

In this paper, we investigate the decay of Higgs boson to $J/ψ(Υ)$ plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process $H \to J/ψ(Υ)+ γ$ direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the $H \to γ^\astγ$ with virtual $γ$ substantially decaying to $J/ψ(Υ)$, including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the $H \to J/ψ(Υ)+ γ$ decay could be observable at a 14 TeV LHC and it also offers a new way to probe the Yukawa coupling and New Physics at the LHC.

hep-ph

Light Curve Solutions of an Eclipsing Binary OGLE-GD-ECL-04451 with a Dramatic Change in Amplitude

We present light curve solutions of the W UMa-type eclipsing binary OGLE-GD-ECL-04451, observed by both the \emph{Optical Gravitational Lensing Ex-periment} (\emph{OGLE}) program in 2006 and the \emph{Antarctica Survey Telescope} (\emph{AST3-1}) in 2012 at Dome A. We analyzed this binary system with the Wilson-Devinney(W-D) method 2013 version and derived the mass ratio $q=2.91 \pm 0.07$, the inclination $i=76.86^\circ \pm 0.23^\circ$, and the light variattion amplitud was $0^m.51$ based on the \emph{OGLE} data. From the \emph{AST3-1}'s data, we find that the amplitude dropped to $0^m.44$(2012) and the difference of magnitudes of the two light maxima is $0^m.03$. A hot spot was then added on the surface of the secondary to demonstrate the amplitude change and O'Conell effect of the binary system.

astro-ph.SR

Dark matter pair associated with a $W$ boson production at the LHC in next-to-leading order QCD

We investigate the QCD next-to-leading order (NLO) corrections to the production of a pair of fermionic dark matter particles associated with a W boson production through a mediator which couples to standard model particles via either a vector or axial-vector coupling at the LHC. We find that the QCD NLO corrections reduce the dependence of the total cross sections on the factorization and renormalization scales, and the $K$-factors increase with the increment of the dark matter mass. We also provide the LO and QCD NLO corrected distributions of the transverse momenta $p_T^μ$ of final muon and transverse mass $M_T$. We find that the LO cross section is significantly changed by the QCD NLO corrections.

hep-ph

Searching for dark matter via mono-$Z$ boson production at the ILC

High energy colliders provide a new unique way to determine the microscopic properties of the dark matter (DM). Weakly interacting massive particles (WIMPs) are widely considered as one of the best DM candidates. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper, we investigate the DM pair production associated with a $Z$ boson in an effective field theory framework at the International Linear Collider (ILC), which can be used to study the interactions between the DM and leptons. For illustrative purposes, we present the integrated and differential cross sections for the $e^+ e^- \rightarrow χ\barχ Z$ process, where the $Z$ boson is radiated from the initial state electron or positron. Meanwhile, we analyze the neutrino pair production in association with a $Z$ boson as the SM background.

hep-ph

Next-to-leading order QCD corrections to $HW^{\pm}γ$ production at the LHC

The Higgs boson production associated with a $W$-boson and a photon at the Large Hadron Collider (LHC) can be used to probe the coupling between Higgs boson and vector gauge bosons and discover a signature of new physics. We present the precision predictions up to the QCD next-to-leading-order (NLO) in the standard model for this process involving the subsequential weak decays of the final Higgs and $W$-boson. The dependence of the leading order (LO) and the QCD NLO corrected integrated cross sections on the factorization/renormalization energy scale is studied. We provide the LO and QCD NLO corrected distributions of the transverse momenta and rapidities of final products. We find that the LO cross section is significantly enhanced by the QCD NLO correction, and the $K$-factor value is obviously related to the physical observables and the phase space regions.

hep-ph

$J/ψ$ production associated with a $W$-boson at the $7 TeV$ LHC

We calculate the complete next-to-leading order (NLO) QCD corrections to the $J/ψ+W$ associated production within the factorization formalism of nonrelativistic QCD at the $7 TeV$ LHC. We provide the numerical results for the leading-order (LO), NLO QCD corrected differential cross sections of the $J/ψ$ transverse momentum by adopting the event selection criteria requested by the ATLAS experiment. We find that the differential cross section at the LO is significantly enhanced by the NLO QCD corrections.

hep-ph

Design and development of the CSNS ion source control system

After the CSNS ion source test stand has been stably working for years, an online control system for CSNS ion source aiming to be more stable and reliable is now under development. F3RP61-2L, a new PLC CPU module under Linux system, is introduced to the system as an IOC, to function together with the I/O modules of FA-M3 PLC on the PLC-bus. The adoption of the new IOC not only simplifies the architecture of the control system, but also improves the data transmission speed. In this paper, the design and development of the supervisory and control system for CSNS ion source are described.

physics.acc-ph

Associated production of $Υ(1S)W$ at LHC in next-to-leading order QCD

We investigate the complete next-to-leading order (NLO) QCD corrections to $Υ(1S) +W$ production at the LHC, and predict theoretically the distribution of the $Υ(1S)$ transverse momentum. We analyse the contributions from different components up to the QCD NLO in the \ppUW process. Our results show that the \ppUW process has a large production rate and could be potentially detected at the LHC. We see that the differential cross section for the $Υ(1S)$ direct-production at the LO is significantly enhanced by the QCD corrections, and the $b\bar{b} [ ^3S_1^{(8)} ]$ contribution component dominates in the whole plotted $p_T^{Υ(1S)}$ region. We have also calculated the $Υ(1S)$ meson indirect-productions via feed-down decays of $Υ(2S)$, $Υ(3S)$, $χ_{b1}(1P)$, $χ_{b2}(1P)$, $χ_{b1}(2P)$, and $χ_{b2}(2P)$ mesons. We find that the $Υ(1S)$ indirect-productions can give important contributions to the distribution of $p_T^{Υ(1S)}$ for the \ppUW process at the NLO. We conclude that the studying the $Υ(1S)+W$ production at the LHC could provide an interesting opportunity in testing the nonrelativistic QCD factorization formalism.

hep-ph

QCD corrections to $J/ψ$ plus $Z^0$-boson production at the LHC

The $J/ψ+Z^0$ associated production at the LHC is an important process in investigating the color-octet mechanism of non-relativistic QCD in describing the processes involving heavy quarkonium. We calculate the next-to-leading order (NLO) QCD corrections to the $J/ψ+Z^0$ associated production at the LHC within the factorization formalism of nonrelativistic QCD, and provide the theoretical predictions for the distribution of the $J/ψ$ transverse momentum. Our results show that the differential cross section at the leading-order is significantly enhanced by the NLO QCD corrections. We conclude that the LHC has the potential to verify the color-octet mechanism by measuring the $J/ψ+Z^0$ production events.

hep-ph

Prompt heavy quarkonium production in association with a massive (anti)bottom quark at the LHC

In this work, we investigate the associated production of prompt heavy quarkonium with a massive (anti)bottom quark to leading order in the NRQCD factorization formalism at the LHC. We present numerical results for the processes involving $J/ψ,χ_{cJ},Υ$ and $χ_{bJ}$. From our work, we find that the production rates of these processes are quite large, and these processes have the potential to be detected at the LHC. When $p_T$ is smaller than about 10 GeV, the $c\bar{c} [ ^1S_0^{(8)} ]$ state give the main contribution to the $p_T$ distribution of prompt $J/ψ$ with a (anti)bottom quark production. For the process of $pp \to Υ+b(\bar{b})$, the contribution of the CSM is larger than that in the COM at low $p_T$ region. We also investigate the processes of $pp\to χ_{cJ}+b(\bar{b})$ and $pp \to χ_{bJ}+b(\bar{b})$, in these processes, the $p_T$ distribution are dominated by the CO Fock state contribution at the large $p_T$ region. These processes provide an interesting signature that could be studied at the LHC, and the measurement of these processes is useful to test the CSM and COM.

hep-ph

QCD corrections to $J/ψ$ production in association with a $W$-boson at the LHC

We calculate the next-to-leading order (NLO) QCD corrections to the $J/ψ+W$ production at the LHC, and provide the theoretical distribution of the $J/ψ$ transverse momentum. Our results show that the differential cross section $\frac{dσ}{dp_T^{J/ψ}}$ at the LO is significantly enhanced by the NLO QCD corrections. We believe that the comparison between the theoretical predictions for the $J/ψ+W$ production and the experimental data at the LHC can provide a verification for the colour-octet mechanism of non-relativistic QCD in the description of the processes involving heavy quarkonium.

hep-ph

The annihilation decays $B^-_c \to η^{'}(η,π^0) l^- \barν$

We investigate the simileptonic OZI-forbidden annihilation decays $B^-_c \to η^{'}(η,π^0) l^- \barν$ for $l=μ,e$ in the perturbative QCD, and carry out a precise calculation without any approximation for the one-loop contributions, which involves integrals of 4- and 5-point loop functions. Our results show that the branching ratios of decays $B^-_c \to η^{'} l^- \barν$, $B^-_c \to ηl^- \barν$ and $B^-_c \to π^0 l^- \barν$, turn out to be of orders $10^{-4}$, $10^{-5}$ and $10^{-6}$, respectively, which could be observable in the future experiments at the LHC.

hep-ph