arXiv subjects

Hai-Bo Li

Publications and source records attributed to Hai-Bo Li.

At least 37 records · Page 2Linked to original sources

arXiv2020

Semileptonic Decay of $D_s^+\to π^0 \ell^+ ν_\ell$ Via Neutral Meson Mixing

Based on the mechanism of neutral meson mixing, we predict the branching fraction of the semileptonic decay of $D_s^+\to π^0 \ell^+ ν_\ell$ ($\ell=e$, $μ$) using recently measured branching fraction of $D_s^+\to ηe^+ν_e$ by BESIII experiment . We also give a formula that can describe the neutral meson mixing of $π^0$, $η$, $η'$ and a pseudoscalar gluonium $G$ in a unified way. The predicted branching fraction of $D_s^+\toπ^0 e^+ν_e$ decay is $\mathcal{B}(D_s^+\toπ^0 e^+ν_e)=(2.65\pm 0.38)\times 10^{-5}$. It is important to search for the decay $D_s^+\to π^0 \ell^+ ν_\ell$ in experiment, in order to understand the mechanism of $π^0$ production in $D_s^+\toπ^0$ transition in semileptonic decay. We also estimate the branching fraction of $D_s^+\to π^0τ^+ν_τ$, which is the only kinematically allowed semi-tauonic decay mode of the charmed meson, since the mass value of $D_s^+$ meson is just slightly above the threshold of $π^0τ^+$ generation in the semi-tauonic decay.

hep-ph↗

arXiv2019

Polarization difference between hyperons and anti-hyperons induced by external magnetic field

We investigate the quantum correlated $Λ\barΛ $ production in the reaction $e^{+}e^{-} \to J/ψ\to Λ\barΛ$. Since the $Λ$ or $\barΛ$ has a nonzero magnetic moment, its spin will undergo a Larmor precession in the magnetic field of the detector, such as the BESIII experiment. Because of the spin precession, the angular distribution of the $Λ$ and $\barΛ$ is slightly modified. Therefore, we obtain the corresponding term of the modified angular distribution due to the effect of the Larmor precession. We also estimate its potential effect on the measurements of $CP$ violation, as well as the decay asymmetry parameter and polarization of $Λ$. The polarization of the $Λ$ or $\barΛ$ at the production vertex will rotate around the $B$-field axis, over an angle depending on the flight length in, but it still could be measured by fit to the corrected angular distribution. Of important, We conclude that a nonzero $CP$ asymmetry of order $10^{-4}$ will be caused once neglecting spin precession of the $Λ$ and $\barΛ$ in the $e^{+}e^{-} \to J/ψ\to Λ\barΛ$ process. The size of this $CP$ asymmetry is several times that of predicted within Standard Model in the hyperon decay. Although this effect is small, it will play an important role in future high precision experiments, such as the super-tau-charm factory.

hep-ph↗

arXiv2019

Study of the electromagnetic Dalitz decays $ψ(Υ) \to η_{c}(η_{b}) l^{+} l^{-}$

We study the electromagnetic Dalitz (EM) decays, $ψ\to η_{c} l^{+} l^{-}$ and $Υ\to η_{b} l^{+} l^{-}$ ($l = e$ or $μ$), in which the lepton pair comes from the virtual photon emitted by the M1 transition from $c\bar{c}$ ($b\bar{b}$) spin triplet state to the spin singlet state. We estimate the partial width of $ψ(Υ) \to η_{c}(η_{b}) l^{+} l^{-}$, based on the simple pole approximation. Besides, based on different QCD models, the partial width of $ψ(Υ) \to η_{c}(η_{b}) γ$ is determined.

hep-ph↗

arXiv2019

Testing SU(3) Flavor Symmetry in Semileptonic and Two-body Nonleptonic Decays of Hyperons

The semileptonic decays and two-body nonleptonic decays of light baryon octet ($T_8$) and decuplet ($T_{10}$) consisting of light $u,d,s$ quarks are studied with the SU(3) flavor symmetry in this work. We obtain the amplitude relations between different decay modes by the SU(3) irreducible representation approach, and then predict relevant branching ratios by present experimental data within $1 σ$ error. We find that the predictions for all branching ratios except $\mathcal{B}(Ξ\rightarrow Λ^0π)$ and $\mathcal{B}(Ξ^*\rightarrow Ξπ)$ are in good agreement with present experimental data, that implies the neglected $C_+$ terms or SU(3) breaking effects might contribute at the order of a few percent in $Ξ\rightarrow Λ^0π$ and $Ξ^*\rightarrow Ξπ$ weak decays. We predict that $\mathcal{B}(Ξ^{-}\rightarrow Σ^0μ^-\barν_μ)=(1.13\pm0.08)\times10^{-6}$, $\mathcal{B}(Ξ^{-}\rightarrowΛ^0μ^-\barν_μ)=(1.58\pm0.04)\times10^{-4}$, $\mathcal{B}(Ω^-\rightarrowΞ^0μ^-\barν_μ)=(3.7\pm1.8)\times10^{-3}$, $\mathcal{B}(Σ^-\rightarrow Σ^0e^-\barν_e)=(1.35\pm0.28)\times10^{-10}$, $\mathcal{B}(Ξ^-\rightarrow Ξ^0e^-\barν_e)=(4.2\pm2.4)\times10^{-10}$. We also study $T_{10}\to T_8 P_8$ weak, electromagnetic or strong decays. Some of these decay modes could be observed by the BESIII, LHCb and other experiments in the near future. Due to the very small life times of $Σ^0$, $Ξ^{*0,-}$, $Σ^{*0,-}$ and $Δ^{0,-}$, the branching ratios of these baryon weak decays are only at the order of $\mathcal{O}(10^{-20}-10^{-13}$), which are too small to be reached by current experiments. Furthermore, the longitudinal branching ratios of $T_{8A} \to T_{8B} \ell^- \barν_\ell~(\ell=μ,e)$ decays are also given.

hep-ph↗

arXiv2019

Prospects for rare and forbidden hyperon decays at BESIII

The study of hyperon decays at the Beijing Electron Spectrometer III (BESIII) is proposed to investigate the events of $J/ψ$ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron--Positron Collider II. About $10^{6}$--$10^8$ hyperons, i.e., $Λ$, $Σ$, $Ξ$, and $Ω$, will be produced in the $J/ψ$ and $ψ(2S)$ decays with the proposed data samples at BESIII. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of $10^{-5}$--$10^{-8}$. In addition, with the known center-of-mass energy and "tag technique," rare decays and decays with invisible final states can be probed.

hep-ex↗

arXiv2018

Study of the isospin breaking decay $\mathbf{\boldsymbol{Y(2175)\rightarrowϕf_0(980)\rightarrowϕηπ^0}}$ at BESIII

Using measured branching fraction of the decay $J/ψ\rightarrowηY(2175))\rightarrowηϕf_0(980)\rightarrowηϕπ^+π^{-}$ from the BESIII experiment, we estimate branching fraction of $J/ψ\rightarrowηY(2175))\rightarrowηϕf_0(980)\rightarrowηϕηπ^{0}$ decay, which proceeds via the $f_0(980)$-$a_0^0(980)$ mixing and the $π^0$-$η$ mixing. The branching fraction is predicted to be about $O(10^{-6})$, which can be accessed with $10^{10}$ $J/ψ$ events collected at the BESIII. The decay is dominated by the contribution from $f_0(980)$-$a_0^0(980)$ mixing. We find that the interference between the amplitudes due to $f_0(980)$-$a_0^0(980)$ mixing and that due to $π^0$-$η$ mixing is destructive. The branching fraction can be decreased by about $10\%$ owing to the interference effect. We also study the $ηπ^0$ mass squared spectrum, and find that a narrow peak due to the $f_0(980)$-$a_0^0(980)$ mixing in the $ηπ^0$ mass squared spectrum should be observed. The observation of this decay in experiment will be helpful to determine the $f_0(980)$-$a_0^0(980)$ mixing intensity and get information about the structures of the light scalar mesons.

hep-ph↗

arXiv2017

CP Asymmetries in Strange Baryon Decays

While indirect & direct CP violations (CPV) had been established in the decays of strange & beauty mesons, none have been done for baryons. There are different "roads" for finding CP asymmetries in the decays of strange baryons; they are highly non-trivial ones. The HyperCP Collaboration had probed CPV in the decays of single $Ξ$ & $Λ$ [Phys.Rev.Lett 93 (2004) 262001]. We talk about future lessons from $e^+e^-$ collisions at BESIII/BEPCII: probing decays of pairs of strange baryons, namely $Λ$, $Σ$ & $Ξ$. Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream to find impact of New Dynamics (ND). We point out that a new important era starts with the BESIII/BEPCII data accumulated by the end of 2018.

hep-ph↗

arXiv2017

Study of $\mathbf{\boldsymbol{D \rightarrow a_0 (980) e^+ ν_e}}$ decay in the light-cone sum rules approach

Within the QCD light-cone sum rule (LCSR) approach, we investigate the transition form factors of $D\rightarrow a_0(980)$ up to the twist-3 light-cone distribution amplitudes (LCDAs) of the scalar meson $a_0(980)$ in the two-quark picture. Using these form factors, we calculate the differential decay widths and branching ratios of the $D\rightarrow a_0(980) e^+ ν_e$ semileptonic decays. We obtain ${\mathcal B}(D^0\rightarrow a_0^- (980) e^+ ν_e)=(4.08^{+1.37}_{-1.22})\times 10^{-4}$ and ${\mathcal B}(D^+\rightarrow a_0^0 (980) e^+ ν_e)=(5.40^{+1.78}_{-1.59})\times 10^{-4}$. The results are sensitive to the $a_0(980)$ inner structure. These decays can be searched for at BESIII experiment, and any experimental observations will be useful to identify internal quark contents of the $a_0(980)$ meson, which will shed light on understanding theoretical models.

hep-ph↗

arXiv2015

Bi-l0-l2-Norm Regularization for Blind Motion Deblurring

In blind motion deblurring, leading methods today tend towards highly non-convex approximations of the l0-norm, especially in the image regularization term. In this paper, we propose a simple, effective and fast approach for the estimation of the motion blur-kernel, through a bi-l0-l2-norm regularization imposed on both the intermediate sharp image and the blur-kernel. Compared with existing methods, the proposed regularization is shown to be more effective and robust, leading to a more accurate motion blur-kernel and a better final restored image. A fast numerical scheme is deployed for alternatingly computing the sharp image and the blur-kernel, by coupling the operator splitting and augmented Lagrangian methods. Experimental results on both a benchmark image dataset and real-world motion blurred images show that the proposed approach is highly competitive with state-of-the- art methods in both deblurring effectiveness and computational efficiency.

cs.CV↗

arXiv2013

Lepton number violation in D meson decay

The lepton number violating process can be induced by introducing a fourth generation heavy Majorana neutrino, which is coupled to the charged leptons of Standard Model. There have been many previous studies on the leptonic number violating decay processes with this mechanism, we follow the trend to study the process: $D \to K \ell \ell π$ with the same-sign dilepton final states. We restrict ourself to certain neutrino mass regions, in which the heavy neutrino could be on shell and the dominant contribution to the branching fraction comes from the resonance enhanced effect. Applying the Narrow Width Approximation, we found that upper limit for the branching fractions for $D^0 \to K^-\ell^+\ell^+π^-$ are generally at the order of $10^{-10}$ to $10^{-9}$, if we take the most stringent upper limit bound currently available in the literature for the mixing matrix elements. We also provide the constrains, which is competitive compared to the LNV B decays, on the mixing matrix element $|V_{eN}|^2$ based on the upper limit of $D^0 \to K^- e^+ e^+ π^-$ estimated from Monte-Carlo study at BESIII.

hep-ph↗

arXiv2012

Quantum wave equation of non-conservative system

It is well known that Schrödinger's equation is only suitable for the particle in conservative force field. In atomic and molecular field, a particle can suffer the action of non-conservative force. In this paper, a new quantum wave equation is proposed, which can describe the particle in non-conservative force field. We think the new quantum wave equation can be used in many fields.

quant-ph↗

arXiv2012

Recent results on charm physics at BESIII

About 2.9 fb$^{-1}$ data set had been collected with the BESIII detector at the BEPCII collider. Taking advantages of data near open-charm threshold, we present preliminary results on leptonic and semileptonic charm-meson decays, as well as result on the FCNC process $D^0 \rightarrow γγ$ from BESIII experiment. High precision charm data will enable us to validate Lattice QCD calculations at the few percent level. These can then be used to make precise measurements of CKM elements, $V_{cd}$ and $V_{cs}$, which are useful to improve the accuracy of test of the CKM unitary.

hep-ex↗

arXiv2012

Study of the electromagnetic transitions $J/ψ\rightarrow P l^+l^-$ and probe dark photon

We study the electromagnetic Dalitz decay modes of $J/ψ\rightarrow P l^+l^-$ ($P= π^0$, $η$ or $η^\prime$). In these decays, the lepton pairs are formed by internal conversion of an intermediate virtual photon with invariant mass $m_{l^+l^-}$. Study of the effective-mass spectrum of the $l^+l^-$ will shed light on the dynamic transition form factor $F_{J/ψP}(q^2)$ ($q^2 = m^2_{l^+l^-}$), which characterizes the electromagnetic structure arising at the vertex of the transition $J/ψ$ to pseudoscalars. We also discuss the direct productions of a GeV scale vector $U$ boson in these processes $J/ψ\rightarrow PU$ ($U\rightarrow l^+l^-$). It is responsible for mediating a new $U(1)_d$ interaction, as recently exploited in the context of weakly interacting massive particle dark matter. In this paper, we firstly use the usual pole approximation for the form factor to estimate the decay rate of $J/ψ\rightarrow P l^+l^-$ in the standard model. Then the reach of searching for the dark photon is estimated. We suggest that these Dalitz decays can be used to search for the light $U$ boson in the BESIII experiment with a huge $J/ψ$ data set.

hep-ph↗

arXiv2012

Light hadron, Charmonium(-like) and Bottomonium(-like) states

Hadron physics represents the study of strongly interacting matter in all its manifestations and the understanding of its properties and interactions. The interest on this field has been revitalized by the discovery of new light hadrons, charmonium- and bottomonium-like states. I review the most recent experimental results from different experiments.

hep-ex↗

arXiv2012

Mini-review of rare charmonium decays at BESIII

Recently, LHCb experiment announced a 3.5$σ$ evidence for direct CP violation in $D^0$ decay by looking at the difference between $A_{CP}(D^0\rightarrow K^+K^-)$ and $A_{CP}(D^0\rightarrow π^+π^-)$. This is the first evidence of CP violation in charm system, which may indicate new physics beyond the Standard Model. Motivated by this measurement, we review rare processes in charmonium decay, especially, the weak decay, $C$ or $P$ violated decay and lepton flavor violated decays. In case the new physics appears in charm sector, these rare decays of charmonium states will provide opportunity to search for significant contributions from physics beyond the Standard Model. With huge $J/ψ$ and $ψ(2S)$ samples in BESIII experiment, the rare decays may be feasible.

hep-ex↗

arXiv2011

Highlights from BESIII experiment

BESIII had collected large data samples on $J/ψ$ and $ψ^\prime$ peaks during the first run in 2009. From 2010 to 2011, about 2.9 fb$^{-1}$ integrated luminosity were obtained on the peak of $ψ(3770)$ for open charm physics. We review recent results on charmonium decays and hadron spectroscopy. The prospects on open charm physics are also discussed.

hep-ex↗

arXiv2011

Study of CP violation in $Λ_c^+$ decay

In this paper, we study CP violation in $Λ_c^+\to BP$ and $Λ_c^+\to BV$ decays, where $B,P$ and $V$ denote a light spin-1/2 baryon, pseudoscalar and a vector meson respectively. In these processes the $T$ odd CP violating triple-product (TP) correlations are examined. The genuine CP violating observables which are composed of the helicity amplitudes occurring in the angular distribution are constructed. Experimentally, by performing a full angular analysis it is shown how one may extract the helicity amplitudes and then obtain the TP asymmetries. We estimate the TP asymmetries in $\lam$ decays to be negligible in the standard model making these processes an excellent place to look for new physics. Taking a two Higgs doublet model, as an example of new physics, we show that large TP asymmetries are possible in these decays. Finally, we discuss how BES-III and Super $τ$-Charm experiments will be sensitive to these CP violating signals in $Λ_c^+$ decays.

hep-ph↗

arXiv2011

Non-factorization contributions in $D\rightarrow πK, KK$ decay

We have analyzed the $D\rightarrow πK, KK$ decay with the naive factorization (NF), QCD factorization (QCDF)and QCD factorization including soft-gluon exchanges (QCDF+SGE). In these decay channels, the soft-gluon effects are firstly calculated with light cone QCD sum rules. Comparing the three kind approaches, we can find the calculation results have made much more improved QCD factorization (QCDF) than the naive factorization (NF), and the calculation results have also made improved QCD factorization including soft-gluon exchanges (QCDF+SGE) than the QCD factorization (QCDF) in the color-suppressed decay channels. In addition, we find the soft-gluon effects are larger than the leading order contributions, and the calculation results are close to the experimental data for the color-suppressed decay channels. In color-allowed decay channel $D^{0}\rightarrow π^{+} K^{-}$, the soft-gluon effects are small and we should consider other power terms, such as final state interaction and annihilation effects.

hep-ph↗