arXiv subjects

Yadong Yang

Publications and source records attributed to Yadong Yang.

14 recordsLinked to original sources

arXiv2026

Low-energy Muon-Nucleon scattering experiment: LUNE (White Paper)

The HIAF will provide high-intensity, high-quality muon beams with momenta from 0.5 to 7.5 GeV/c. This energy range is uniquely suited for precision muon scattering, bridging the gap between low-energy electron facilities and future high-energy lepton-ion colliders. In particular, HIAF will enable precision measurements with both positive and negative muon beams over a broad kinematic range, complementing existing electron-scattering facilities such as JLab, EicC and EIC. Based on HIAF muon source, the LUNE Collaboration has been established to address several fundamental questions in nuclear and particle physics, including the proton charge radius puzzle, nucleon electromagnetic structure, and the dynamics of quantum electrodynamics and hadronic interactions. The program proceeds in two phases, from elastic scattering to nucleon structure and beyond-Standard-Model searches. The experiment is expected to determine the proton charge radius with a precision of approximately 1.0\% using elastic muon-proton scattering. It will also perform systematic measurements of the proton electromagnetic form factors with both $\mu^+$ and $\mu^-$ beams, enabling precise studies of two-photon exchange effects and stringent tests of quantum electrodynamics. Beyond elastic scattering, LUNE will investigate TMD, gravitational form factors, and nuclear charge radii, providing new insights into the 3D structure of nucleons and nuclei. The experiment will further address important topics including Coulomb-distortion corrections, nuclear medium effects, and possible signatures of physics beyond the Standard Model. This white paper presents the scientific motivation, detector concept, expected performance, and long-term strategy of LUNE.

hep-ex↗

arXiv2023

Using evolutionary machine learning to characterize and optimize co-pyrolysis of biomass feedstocks and polymeric wastes

Co-pyrolysis of biomass feedstocks with polymeric wastes is a promising strategy for improving the quantity and quality parameters of the resulting liquid fuel. Numerous experimental measurements are typically conducted to find the optimal operating conditions. However, performing co-pyrolysis experiments is highly challenging due to the need for costly and lengthy procedures. Machine learning (ML) provides capabilities to cope with such issues by leveraging on existing data. This work aims to introduce an evolutionary ML approach to quantify the (by)products of the biomass-polymer co-pyrolysis process. A comprehensive dataset covering various biomass-polymer mixtures under a broad range of process conditions is compiled from the qualified literature. The database was subjected to statistical analysis and mechanistic discussion. The input features are constructed using an innovative approach to reflect the physics of the process. The constructed features are subjected to principal component analysis to reduce their dimensionality. The obtained scores are introduced into six ML models. Gaussian process regression model tuned by particle swarm optimization algorithm presents better prediction performance (R2 > 0.9, MAE < 0.03, and RMSE < 0.06) than other developed models. The multi-objective particle swarm optimization algorithm successfully finds optimal independent parameters.

cs.LG↗

arXiv2006

Reexamining charmless B\to PV decays in QCD factorization approach

Using the QCD factorization approach, we reexamine the two-body hadronic charmless $B$-meson decays to final states involving a pseudoscalar~($P$) and a vector~($V$) meson, with inclusion of the penguin contractions of spectator-scattering amplitudes induced by the $b\to D g^\ast g^\ast$~(where $D=d$ or $s$, and $g^\ast$ denotes an off-shell gluon) transitions, which are of order $α_s^2$. Their impacts on the CP-averaged branching ratios and CP-violating asymmetries are examined. We find that these higher order penguin contraction contributions have significant impacts on some specific decay modes. Since $B\to πK^{\ast}$, $K ρ$ decays involve the same electro-weak physics as $B\to πK$ puzzles, we present a detailed analysis of these decays and find that the five R-ratios for $B\to πK^{\ast}$, $K ρ$ system are in agreement with experimental data except for $R(πK^*)$. Generally, these new contributions are found to be important for penguin-dominated $B\to PV$ decays.

hep-ph↗

arXiv2006

τ^- \to μ^- π^0(η,η') Decays in New Physics Scenarios beyond the Standard Model

The semileptonic decays $τ^- \to μ^- M (M=π^0,η,η')$ could be sensitive probe for new physics scenarios with lepton flavor violation(LFV). Motivated by the recent Belle measurement, we investigate these decays in type III two-Higgs-doublet model (2HDM III), R-parity violating supersymmetric models(RPV SUSY) and flavor changing $Z'$ models with family non-universal couplings, respectively. In these new physics scenarios, there are LFV couplings at tree level. Our results have shown that the decays are very sensitive to the LFV couplings and could be enhanced to the present experimental sensitivities. We have derived strong bounds on relevant couplings of these models, which may be useful for further relevant studies.

hep-ph↗

arXiv2005

Testing the chirality of b to u current with B^0 \to ρ^ - \ell^+ ν

We study the effects of a modest V+A admixture strength in $b\tou$ current in the decay $B \toρl ν$. We have shown that the decay rate, lepton forward-backward distribution asymmetry $A_{FB}$ and polarization ratio are sensitive to the admixture. Future experimental studies of the decay at BaBar and BELLE could clarify the chirality of $b\to u$ current and might reveal hints for New Physics with right-handed quark currents.

hep-ph↗

arXiv2004

Charmless $\bar{B}_s\to VV$ Decays in QCD Factorization

The two body charmless decays of $B_s$ meson to light vector mesons are analyzed within the framework of QCD factorization. This approach implies that the nonfactorizable corrections to different helicity amplitudes are not the same. The effective parameters $a_i^h$ for helicity $h=0,+,-$ states receive different nonfactorizable contributions and hence are helicity dependent, contrary to naive factorization approach where $a_i^h$ are universal and polarization independent. The branching ratios for $\bar{B}_s\to VV$ decays are calculated and we find that branching ratios of some channels are of order $10^{-5}$, which are measurable at future experiments. The transverse to total decay rate $Γ_T/Γ$ is also evaluated and found to be very small for most decay modes, so, in charmless $\bar{B}_s\to VV$ decays, both light vector mesons tend to have zero helicity.

hep-ph↗

arXiv2003

The Rare Radiative Annihilation Decays $\bar{B}^0_{s,d} \to J/ψγ$

We investigate the physics potential of the annihilation decays $\bar{B}^0_{s,d} \to J/ψ$ $γ$ in the Standard Model and beyond. In naive factorization approach, the branching ratios are estimated to be $\mathcal{B}(\bar{B}^0_s \to J/ψγ)=1.40\times 10^{-6}$ and $\mathcal{B}(\bar{B}^0_d \to J/ψγ)=5.29\times 10^{-8}$. In the framework of QCD factorization, we compute the non-factorizable corrections and get $\mathcal{B}(\bar{B}^0_s \to J/ψγ) = 2.11\times10^{-7}$, $\mathcal{B}(\bar{B}^0_d \to J/ψγ) =7.65\times10^{-9}$. Future measurements of these decays would be useful for testing the factorization frameworks. The smallness of these decays in the SM make them sensitive probes of New Physics. As an example, we will consider the possible admixture of (V+A) charge current to the standard (V-A) current. This admixture will give significant contributions to the decays.

hep-ph↗

arXiv2002

Semi-inclusive Decay $B\to ϕX_s$: Rate and Momentum Spectrum of $ϕ$

We study the rate and $ϕ$ momentum distribution in semi-inclusive decays $B \toϕX_s $ induced by the quark level processes $b\toϕs$ and $b\toϕs g$, in which the gluon is radiated from the internal charm quark loop or emitted from the virtual gluon of the strong penguin (inner bremsstrahlung). We find ${\cal B}(b\toϕs)=6.7\times 10^{-5}$ and ${\cal B}(b\toϕs g)=3.8\times 10^{-5}$. The momentum spectrum of $ϕ$ produced by $b\toϕs g $ is very broad. With the cut $|{\bf k}_ϕ|\geq 2.0$ GeV, ${\cal B}(b\toϕs)=6.1\times 10^{-5}$ (where the Fermi motion of the $b$-quark in the $B$-meson is described by a Gaussian), and ${\cal B}(b\toϕs g)=1.0\times 10^{-5}$. Due to the special nature of $ϕ$, many difficulties which hindered a reliable theoretical prediction for $B\to η' X_s$ decay are absent in the process $B\to ϕX_s$. Therefore, theoretical predictions for $B\to ϕX_s$ are relatively clean. Moreover, the clear experimental signature of the $ϕ$ is of great help. Data for $B\toϕX_s$, both the branching ratio and the $ϕ$ momentum distribution, would teach us about the strength of strong penguins which might be of great importance in the search for CP violation and for new physics at $B$ factories.

hep-ph↗

arXiv1999

The annihilation decay B_c \to eta' l ν

We first investigate the semileptonic annihilation decay B_c \to η' lνin QCD. We find that the $η'$ momentum distribution is peaked within its small recoil region due to the loop effects. The branching ratio is estimated to be $ Br(B_c \to η' lν)=1.6\times 10^{-4}$ for $l=μ,e$, which is accessible at CERN LHC.

hep-ph↗

arXiv1998

Further Analysis of $B \to η^{\prime} K(K^),ηK(K^)$ Processes

Combining three mechanisms, we reanalysis processes of $B \to η^{\prime} K(K^*),ηK(K^*)$ and calculate their branching ratios. The results are compared with other mechanisms in the literature. The striking feature of the gluon fusion mechanism is emphasized and its experimental test is discussed.

hep-ph↗

arXiv1998

A New Mechanism for $B^{\pm}\to η'K^{\pm}$ in Perturbative QCD

We present a new mechanism for $B^{\pm}\to η' K^{\pm}$, and analyze it strictly within perturbative QCD. We find that such a new mechanism may dominate non-leptonic $B$-decays to light mesons. Within a reasonable parameter space, our prediction is in good agreement with the recent CLEO data on $B^{\pm}\to η' K^{\pm}$. We conclude that there is no room for an abnormally large \bsg vertex from physics beyond the Standard Model.

hep-ph↗

arXiv1997

Reexamination of the resonance contributions in B->X_s e^+ e^-

With help of the recent developments in the heavy quarkonium physics, we reexamine the long distance(LD) effects in \Bsee dominantly from the charmonium resonances $J/Ψ$ and $Ψ^{\prime}$ through the decay chains $B\ra X_s J/Ψ(Ψ^{\prime}) \ra X_s e^+ e^-$. We find that the resonance to nonresonance interference are reduced substantially.

hep-ph↗

arXiv1997

Probe New Physics in Leptonic $ B_c$ Decays at CERN LHC

With respect to large samples of $B_c$ mesons expected to be produced at CERN Large Hadron Collider(LHC) and the large branching ratios $Br(B_{c}\to τ\barν)$ and $Br(B_{c}\to μ\barν)$, we suggest that $B_c$ purely leptonic decays could offer an unique probe of the standard model and its extensions such as two Higgs doublet models and models involving supersymmetry, and also the structure of charged weak currents.

hep-ph↗

arXiv1996

A study on the rare radiative decay $B_c \to D_s^* γ$

We study the decay $B_c \rightarrow D_s^* γ$. There are two mechanisms contributing to the process. One proceeds through the short distance $b{\rightarrow}sγ$ transition and the other occurs through weak annihilation accompanied by a photon emission.The electromagnetic penguin contribution is estimated by perturbative QCD and found to be $4.68\times10^{-18}$ GeV. In particular, we find the contribution of the weak annihilation is $6.25\times10^{-18}GeV$ which is in the same order as that of the electromagnetic penguin. The total decay rate $Γ(B_c \rightarrow D_s^* γ)$ is predicted to be $1.45\times10^{-17}GeV$ and the branching ratio $Br(B_c \rightarrow D_s^* γ)$ is predicted to be $2.98\times 10^{-5}$ for $τ_{B_c}=1.35ps$. The the decays $B_c \rightarrow D_s^* γ$ can be well studied at LHC in the near future.

hep-ph↗