Related papers: Fifth Force and Hyperfine Splitting in Muonic Atom…
Two recent experimental observations at the ATOMKI Institute of the Hungarian Academy of Sciences (regarding the angular emission pattern of electron-positron pairs from nuclear transitions from excited states in 8Be and 4He) indicate the…
Axion-like particles and similar new pseudoscalar as well as vector bosons coupled to nucleons and electrons are predicted to lead to spin-dependent forces in atoms and ions. We argue that hyperfine structure measurements in hydrogen- and…
Motivated by the ATOMKI anomalies in 8Be and 4He transitions, we study X17-induced Lamb shifts and hyperfine splittings in muonic atoms with stable nuclei up to Z <= 15. The bound-state problem is solved within the Gaussian Expansion Method…
Recent anomalies in $^8$Be and $^4$He nuclear decays can be explained by postulating a fifth force mediated by a new boson $X$. The distributions of both transitions are consistent with the same $X$ mass, 17 MeV, providing kinematic…
Experimental searches for fifth forces coupled to muons are fundamentally limited by the scarcity of muons in ordinary matter, whereas neutron stars contain abundant muon populations. We show that these compact objects therefore provide…
A new fifth force between particles carrying $B-L$ charges is well-motivated by the intriguing $U(1)_{B-L}$ extension of the standard model. The gauge boson mediator, F\'eeton, also serves as a dark matter candidate. In this letter, we…
Experimental searches for new, "fifth" forces are attracting a lot of attention because they allow to test theoretical extensions to the standard model. Here, we report a new experimental search for possible fifth forces, specifically…
Spin-dependent fifth-forces are associated with particles beyond the standard model. In particular, light pseudo-scalar bosons mediate long-range forces, allowing mass to interact with spins. The search of these interactions can be…
The discovery of neutrino oscillations implies that neutrinos are massive and mixed, necessitating an extension of the Standard Model, which may require the introduction of non-standard neutrino interactions (NSI). We investigate the…
Precision atomic spectroscopy provides a solid model independent bound on the existence of new dark forces among the atomic constituents. We focus on the keV-GeV region investigating the sensitivity to such dark sectors of the recent…
Ultralight scalar dark matter may induce apparent oscillations of the muon mass, which may be directly probed via temporal shifts in the spectra of muonium and muonic atoms. Existing datasets and ongoing spectroscopy measurements with…
The proposed protophobic fifth force in \emph{Phys. Rev. Lett. {\bf \emph{117}}, 071803 (2016)} recently attracts much attention. To confirm or refute the existence of this new interaction, here I propose a method to probe the protophobic…
New physics motivated by muonic puzzles (proton radius and muon $g-2$ discrepancies) is studied. Using a light scalar boson $\phi$, assuming Yukawa interactions, accounts for these muonic puzzles simultaneously. Our previous work limits the…
In the framework of the quasipotential method in quantum electrodynamics we calculate the contribution of light pseudoscalar (PS) and axial-vector (AV) mesons to the interaction operator of a muon and a proton in muonic hydrogen atom. The…
Hitherto unknown elementary particles can be searched for with atomic spectroscopy. We conduct such a search using a potential that results from the longitudinal polarization of a pseudovector particle. We show that such a potential,…
We revisit the contribution of axial-vector mesons to the hyperfine splitting of muonic hydrogen. We focus our attention on the doubly-virtual asymptotic behavior of the relevant form factors of axial-vector mesons, together with their…
Recently, a peak in the light fermion pair spectrum at invariant q^2 approximately equal to 16.7 Me^2. has been observed in the bombardment of Li-7 by protons. This peak has been interpreted in terms of a protophobic interaction of fermions…
Atomic spectroscopy can be used to search for new bosons that carry exotic forces between elementary fermions. A comparison of a recent precise measurement [Bullis \textit{et al.}, Phys. Rev. Lett. \textbf{130}, 203001 (2023)] of the…
We investigate a fifth force mediated by a light vector boson that couples to lepton spins, characterized by axial-vector couplings to leptons and vector couplings to nucleons. This interaction generates a potential proportional to the…
Current discrepancy between the measurement and the prediction of the muon anomalous magnetic moment can be resolved in the presence of a long-range force created by ordinary atoms acting on the muon spin via axial-vector and/or…