arXiv subjects

Dominik Suelmann

Publications and source records attributed to Dominik Suelmann.

4 recordsLinked to original sources

arXiv2025

Probing invisible particles with charm

We point out opportunities to probe invisible particles, left- and right-handed neutrinos, axion-like particles (ALPs) and dark photons $(Z^\prime)$ with rare decays of charm hadrons. We employ and recast existing searches in $D \to (\pi, \omega) X$, $D^ 0 \to X$ and $\Lambda_c \to p X$, where $X$ denotes one of the above invisible final states including dineutrinos. The branching ratios are clean null tests of the standard model, yet, are essentially unconstrained for some parameters of light new physics, limited only by weak lifetime constraints at the level of $\mathcal{O}(10^{-1})$. On the other hand, if models are probed, branching ratios still reach up to $10^{-3}$ ($Z^\prime$) and $10^{-4}$ (ALPs). Chirality-preserving operators from heavy new physics in the dimension six standard model effective theory (SMEFT) imply tighter upper limits, up to few $\times 10^{-5}$. Constraints on chirality-flipping heavy new physics, such as lepton number violation from dimension seven SMEFT, or with light sterile neutrinos, are weaker, with branching ratios up to few$\times 10^{-4}$. Sensitivities to different couplings arise with $\Lambda_c \to p X $ and $D \to \pi \pi X$ decays, in particular in relation with the other modes. Processes can be studied at running and future experiments with high charm luminosities, BESIII, Belle II, a super-tau-charm factory (STCF) and $Z$-factories, such as the FCC-ee and the CEPC.

hep-ph↗

arXiv2025

New opportunities for rare charm from $Z\to c\bar{c}$ decays

We analyze the potential of rare charm decays as probes of new physics at a high-luminosity flavor facility operating at the $Z$ pole, such as the FCC-ee or CEPC. In particular, we identify clean null-test observables in $D^0 \to \pi^+ \pi^- \nu\bar{\nu}$ and in polarized $\Lambda_c^+ \to p \ell^+ \ell^-$ decays with $\ell=e, \mu$. Complementarity with the LHC and HL-LHC flavor programs arises from the characteristic features of a Tera-$Z$ environment: the capability to study missing-energy modes and charm production with significant polarization. We improve the theoretical description of $D^0 \to \pi^+ \pi^- \nu\bar{\nu}$ decays and work out the phenomenology of polarization-induced null-test observables in $\Lambda_c^+ \to p \ell^+ \ell^-$ decays. In regions of dilepton mass near the $\phi$ resonance, polarization asymmetries can reach $O(5 \%)$ for muons and $O(14 \%)$ for electrons times the $\Lambda_c^+$ polarization. We also point out synergies between the dineutrino and the dilepton modes using the SMEFT framework of heavy new physics. Using the IDEA detector concept at FCC-ee, we find in simulation studies that dineutrino branching fractions as low as $\sim 2 \times 10^{-7}$ can be probed, which reaches well into the parameter space of new physics, and also allows for discrimination of lepton flavor structures. Furthermore, the measurement of asymmetries in $\Lambda_c^+ \to p \mu^+ \mu^-$ at $O(1 \%)$ will be possible. Similar sensitivities are expected for dielectron final states, although robust predictions will require further dedicated studies.

hep-ph↗

arXiv2025

BSM reach of rare charm decays, including the rising star $\Lambda_c\to p\mu^+\mu^-$

We perform the first global fit of rare charm transitions using recent data on $D^0\to \mu^+\mu^-$, $D^+\to\pi^+\mu^+\mu^-$, $\Lambda_c\to p\mu^+\mu^-$ and $D^0\to\pi^+\pi^-\mu^+\mu^-$ decays, including angular observables. We work out constraints on new physics in the framework of the weak effective field theory. While angular observables in $D^0\to\pi^+\pi^-\mu^+\mu^-$ decays provide sensitivities to different QCD models, future null tests in $\Lambda_c\to p \mu^+\mu^-$ look more promising to extract limits because of less hadronic uncertainties. This marks $\Lambda_c\to p \mu^+\mu^-$ as the rising star of rare charm decays.

hep-ph↗

arXiv2024

Effective field theory analysis of rare $|\Delta c|=|\Delta u|=1$ charm decays

We perform a global analysis of $|\Delta c| = |\Delta u| = 1$ transitions using recent data on $D^0 \to \mu^+\mu^-$, $D^+ \to \pi ^+\,\mu^+\mu^-$, $\Lambda_c \to p\,\mu^+\mu^-$, and $D^0 \to \pi^+\pi^-\,\mu^+\mu^-$ decays, and work out constraints on new physics Wilson coefficients $\mathcal{C}_{7,9,10}^{(\prime)}$. While results are consistent with the standard model, we find sizeable room for new physics that can be cleanly signaled with null test observables, not probed with searches in other sectors such as kaon and $b$-decays. The decay $D^0 \to \pi^+\pi^-\,\mu^+\mu^-$ requires better understanding of hadronic contributions to be competitive in the current fit. Progress can be achieved by precision study of the double differential decay rate in the dipion and dimuon masses, together with improved theory modelling and $D \to \pi \pi$ transition form factors. On the other hand, the 4-body decay is an important contributor to the future global analysis due to its angular distributions that probe complementary combinations of Wilson coefficients, and as a QCD laboratory. The decay $\Lambda_c \to p\,\ell^+\ell^-$ is the rising star due to the simplicity of a 3-body decay with available form factors from lattice QCD, sensitivity to both 4-fermion and electromagnetic dipole couplings and its null test forward-backward asymmetry.

hep-ph↗