相关论文: Ab initio investigation of the $^7$Li($p,e^+e^-$)$…
We apply the No-Core Shell Model with Continuum (NCSMC) that is capable of describing both bound and unbound states in light nuclei in a unified way with chiral two- and three-nucleon interactions as the only input. The NCSMC can predict…
Angular correlation spectra of $e^+e^-$ pairs produced in the $^{7}$Li($p$,$\gamma$)$^{8}$Be nuclear reaction have been studied at the sharp $E_p$= 441 keV resonance as well as at $E_p$= 650 keV, 800 keV and 1100 keV proton beam energies.…
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…
The observation of a resonance structure in the opening angle of the electron-positron pairs in the $^{7}$Li(p,\ee) $^{8}$Be reaction was claimed and interpreted as the production and subsequent decay of a hypothetical particle (X17).…
The production of $^7$Be and $^7$Li nuclei plays an important role in primordial nucleosynthesis, nuclear astrophysics, and fusion energy generation. The $^3\mathrm{He}(\alpha , \gamma) ^7\mathrm{Be}$ and $^3\mathrm{H}(\alpha , \gamma)…
We present a hypothesis that the anomaly in the folding angle distribution of electron-positron pairs, emitted in the decay of the excited levels of nucleus $^{8}$Be and $^{4}$He can be related to the cluster structure of the decaying…
Recently, when examining the differential internal pair creation coefficients of $^8$Be, $^4$He and $^{12}$C nuclei, we observed peak-like anomalies in the angular correlation of the e$^+$e$^-$ pairs. This was interpreted as the creation…
Energy-sum and angular correlation spectra of $e^+e^-$ pairs produced in the $^{3}$H(p,$\gamma$)$^{4}$He nuclear reaction have been studied at $E_p$=510, 610 and 900 keV proton energies. The main features of the spectra can be understood by…
The $^7$Li(p,n)$^7$Be reaction is widely used as neutron source for neutron induced reaction cross section measurements, and for $^7$Be radioactive source production. There are two prominent structures in the excitation function, a narrow…
Background: Lithium plays an important role in nuclear astrophysics, fusion energy generation, and nuclear technology. From a theoretical point of view, the nucleus $^7$Li presents a remarkable challenge, as its bound states and resonances…
In recent electron-positron angular correlation measurements the observed significant enhancements relative to the internal pair creation at large angles was interpreted as indication of the creation of $J^{\pi }=1^{+}$ boson called X17…
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 observed electron-positron pairs from the electro-magnetically forbidden M0 transition depopulating the 21.01 MeV 0$^-$ state in $^4$He. A peak was observed in their $e^+e^-$ angular correlations at 115$^\circ$ with 7.2$\sigma$…
Electron-positron angular correlations were measured for the isovector magnetic dipole 17.6 MeV state ($J^\pi=1^+$, $T=1$) $\rightarrow$ ground state ($J^\pi=0^+$, $T=0$) and the isoscalar magnetic dipole 18.15 MeV ($J^\pi=1^+$, $T=0$)…
The 6.8$\sigma$ anomaly in excited 8Be nuclear decays via internal pair creation is fit well by a new particle interpretation. In a previous analysis, we showed that a 17 MeV protophobic gauge boson provides a particle physics explanation…
We propose a direct search for the X17 particle, which was conjectured to explain the ATOMKI $^8$Be and $^4$He anomalies, through the dilepton photoproduction process on a nucleon in the photon energy range below or around the pion…
The angular distributions of $^{8}$Be states in the excitation energy region, E$_{x}$ $\ \sim$($16.5-18.2$) MeV, produced in the $^{7}$Li($^{3}% $He,d)$^{8}$Be proton transfer reaction have been measured at the Orsay 14.8$-$MV tandem…
The present work deals with $e^+$-$e^-$ pair production in the four-nucleon system. We first analyze the process as a purely electromagnetic one in the context of a state-of-the-art approach to nuclear strong-interaction dynamics and…
The anomaly found in the excited $^8\text{Be}$ nuclear transition to its ground state is attributed to a spin-1 gauge boson $X(16.7)$. To hunt for this boson, we propose two traps: $e^+e^-\to X\gamma$ and $J/\psi\to X\gamma$, both following…
Observations of anomalous angular correlations in electron-positron pairs produced from excited states of $^{4}$He, $^{8}$Be and $^{12}$C nuclei have been suggested as due to the creation and subsequent decay of a new light particle of mass…