Related papers: Probing the ATOMKI X17 vector boson using Dalitz d…
The recent ATOMKI experiments provided evidence pointing towards the existence of an X17 boson in the anomalous nuclear transitions of Beryllium-8, Helium-4, and Carbon-12. In this work, we consider X17 boson contributions to the previously…
The anomalies recently reported in lepton pair transitions of $^8$Be$^*$ and $^4$He nuclei may be attributed to the existence of a feebly interacting light vector boson $X17$. We study the effects of this hypothetical particle in the…
We report the first measurement of the di-electron invariant mass dependent transition form factor in the electromagnetic Dalitz decay $J/\psi \to e^+e^- \pi^0$ using $(10087 \pm 44) \times 10^6$ $J/\psi$ events collected by the BESIII…
Within the hidden local symmetry framework, the Dalitz decay ${\eta}^{\prime}$ ${\to}$ $Ve^{+}e^{-}$ is studied with the vector meson dominance model. It is found that the partial width ${\Gamma}({\eta}^{\prime}{\to}{\omega}e^{+}e^{-})$…
Observables of light hadron decays are analyzed in a model of chiral Lagrangian which includes resonance fields of vector mesons. In particular, transition form factors are investigated for Dalitz decays of $V\to Pl^+l^-$ and $P\to \gamma…
Using a data sample of $(448.1 \pm 2.9)\times10^6 ~\psi(3686)$ decays collected at an $e^+ e^-$ center-of-mass energy of $3.686~\rm{GeV}$ by the BESIII detector at BEPCII, we report an observation of the hindered electromagnetic Dalitz…
By analyzing a 2.93~$\rm fb^{-1}$ data sample of $e^+e^-$ collisions, recorded at a center-of-mass energy of 3.773 $\rm \,GeV$ with the BESIII detector operated at the BEPCII collider, we have searched for the semileptonic $D^+$ transition…
We report corrected results on a study of the electromagnetic Dalitz decay $J/\psi \to e^+e^- \eta$ and search for di-electron decays of a light dark gauge boson ($\gamma'$) in $J/\psi \to \gamma' \eta$ with the two $\eta$ decay modes $\eta…
An anomaly observed recently in the $^8$Be nuclear transition by the Atomki collaboration hints at a weakly-coupled, light new gauge boson with a mass of about $17$ MeV. In this paper, we propose that this new gauge boson comes from a…
We report the first observation of the Dalitz decay $\eta' \to \gamma e^+e^-$, based on a data sample of 1.31 billion $J/\psi$ events collected with the BESIII detector. The $\eta'$ mesons are produced via the $J/\psi \to \gamma \eta'$…
Using a data sample of $(2.712 \pm 0.014)\times10^{9}$ $\psi(3686)$ events collected at $\sqrt{s}=3.686$ GeV by the BESIII detector, we search for the rare electromagnetic Dalitz decays $\chi_{cJ}\to e^+e^-\phi~(J=0,\,1,\,2)$ via the…
We study the electromagnetic Dalitz decay modes of $J/\psi \rightarrow P l^+l^-$ ($P= \pi^0$, $\eta$ or $\eta^\prime$). In these decays, the lepton pairs are formed by internal conversion of an intermediate virtual photon with invariant…
Dalitz decays of a hyperon resonance to a ground-state hyperon and an electron-positron pair can give access to some information about the composite structure of hyperons. We present expressions for the multi-differential decay rates in…
Employing the $^{11}$B(p,$\gamma$)$^{12}$C nuclear reaction, the angular correlation of $e^+e^-$ pairs was investigated in the angular range of $40^\circ\Theta\leq 175^\circ$ for five different proton energies between E$_p$ = 1.50 - 2.50…
We derive constraints on the couplings of light vector particles to all first-generation Standard Model fermions using leptonic decays of the charged pion, $\pi^+\to e^+ \nu_e X_\mu$. In models where the net charge to which $X_\mu$ couples…
Using $e^+e^-$ data taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, corresponding to an integrated luminosity of 20.3 fb$^{-1}$, we report the first measurement of the decay dynamics of the semileptonic decays…
Studies of D and B mesons decays into hadrons have been used to test the standard model in the last fifteen years. A heavy meson decay involves the combined effects of a primary weak vertex and subsequent hadronic final state interactions,…
Using a sample of about 10 billion $J/\psi$ events collected at a center-of-mass energy $\sqrt s = 3.097$ GeV with the BESIII detector, the electromagnetic Dalitz decays $J/\psi \to e^+e^- \pi^+ \pi^- \eta'$, with $\eta'\to\gamma\pi^+…
Based on 3.19 fb$^{-1}$ of $e^+e^-$ collision data accumulated at the center-of-mass energy 4.178 GeV with the BESIII detector operating at the BEPCII collider, the electromagnetic Dalitz decay $D^{\ast 0}\to D^{0}e^{+}e^{-}$ is observed…
We present Dalitz plot analyses for the decays of $B$ mesons to $D^- D^0 K^+$ and $\overline{D}^0 D^0 K^+$. We report the observation of the $D^{*}_{s1}(2700)^+$ resonance in these two channels and obtain measurements of the mass…