Related papers: The REDTOP experiment: Rare $\eta/\eta^{\prime}$ D…
The $\eta$ and $\eta$' mesons are almost unique in the particle universe since they are Goldstone and the dynamics of their decays are strongly constrained. Because the $\eta$ has no charge, decays that violate conservation laws can occur…
The REDTOP experiment is a proposed super-$\eta$/$\eta'$ factory aimed at exploring physics beyond the Standard Model in the MeV-GeV range and rare $\eta$/$\eta'$ meson decays. With projected production rates exceeding $10^{13}$ $\eta$/year…
Decays of both $\eta$ and $\eta^\prime$ provide very useful information in our understanding of low-energy QCD, and experimental signatures for these decays would be extremely helpful at BES-III. The rare decays of the $\eta$ and…
In this work we investigate the possibility to observe $C\!P$-violation in $\eta$ decays containing muons at the proposed REDTOP experiment. Employing the SMEFT to parametrize the new-physics $C\!P$-violating effects, we find that a single…
In this study, we investigate the imprints of $C\!P$ violation in certain $\eta$ muonic decays that could arise within the Standard Model effective field theory. In particular, we study the sensitivities that could be reached at REDTOP, a…
The upcoming Mu3e experiment aims to search for the lepton flavour violating decay $\mu^+ \to e^+ e^- e^+$ with an unprecedented final sensitivity of one signal decay in $10^{16}$ observed muon decays by making use of an innovative…
A next-generation rare pion decay experiment, PIONEER, is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of lepton flavor universality. It will probe…
We study theoretically the feasibility of the semi-exclusive $^{12}$C($p,dp$)$X$ reaction for the observation of $\eta^\prime$ mesic nuclei using the microscopic transport model JAM. The semi-exclusive measurements of the ($p,d$) reaction…
Decays of the neutral and long-lived $\eta$ and $\eta'$ mesons provide a unique, flavor-conserving laboratory to test low-energy Quantum Chromodynamics and search for new physics beyond the Standard Model. They have drawn world-wide…
A first observation of the rare decay $\eta$ $\to$ $\mu^+\mu^-$e$^+$e$^-$ is reported by the CMS Collaboration at the CERN LHC. The result is based on a proton-proton collision data sample at $\sqrt{s}$ = 13.6 TeV corresponding to an…
The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the…
We provide model-independent bounds on the rates of rare decays $\eta (\eta^\prime) \to \pi\pi$ based on experimental limits on the neutron electric dipole moment (nEDM). Starting from phenomenological $\eta(\eta^\prime) \pi\pi$ couplings,…
The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the…
Rare and very rare decays of third-generation particles, including $b$-hadrons and $\tau$ leptons, provide sensitive probes of physics beyond the Standard Model (SM). Unlike direct searches limited by collider energies, they probe new…
Nowadays the field of searching for a new physics became a very interesting subject in a light meson decays due to a recent results from KTeV collaboration which found the 3.3\sigma\ disagreement between Standard Model theory and their…
In this work we investigate the prospect of observing new-physics signatures via $C\!P$ violation in $\eta^{(\prime)}\to\pi^0\mu^+\mu^-$ and $\eta^\prime\to\eta\mu^+\mu^-$ decays at the REDTOP experiment. We make use of the SMEFT to…
A search for the rare $\eta$ $\to$ $\mu^+\mu^-\mu^+\mu^-$ double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers in 2017-2018 and…
The Standard Model predicts several rare Higgs boson decay channels, among which are the decays to a Z boson and a photon, to a low-mass lepton pair and a photon, and to a meson and a photon. The observation of some of these decays could…
The world's largest sample of $J/\psi$ events accumulated at the BESIII dector offers a unique opportunity to investigate $\eta$ and $\eta^\prime$ physics via two body $J/\psi$ radiative or hadronic decays. In recent years the BESIII…
Patterns of chiral symmetry violation and tests of the conservation of the fundamental C, P and CP symmetries are key physics issues in studies of the pi0, eta and eta' meson decays. These tests include searches for rare or forbidden decays…