235 citations · 2.2k across the 57 of their papers we have counts for
61 papers
New physics in multi-lepton tau decays
Yohei Ema, Patrick J. Fox, Matheus Hostert +4
Dark particles with lepton-flavor-violating couplings to the tau lepton can induce rare neutrinoless decays with large final state multiplicities. We study models where transit…
Cancellation of loop corrections to soft scalar power spectrum
Yohei Ema, Muzi Hong, Ryusuke Jinno +1
We prove the absence of scale-invariant one-loop corrections to the superhorizon curvature perturbations from small-scale (potentially enhanced) scalar perturbations in a general i…
Physics Briefing Book: Input for the 2026 update of the European Strategy for Particle Physics
Jorge de Blas, Monica Dunford, Emanuele Bagnaschi +127
The European Strategy for Particle Physics (ESPP) reflects the vision and presents concrete plans of the European particle physics community for advancing human knowledge in fundam…
Long-lived Axion-Like Particles from Tau Decays
Yohei Ema, Patrick J. Fox, Matheus Hostert +4
Axion-like particles (ALPs) are well-motivated examples of light, weakly coupled particles in theories beyond the Standard Model. In this work, we study long-lived ALPs coupled exc…
On-shell recursion relations for higher-spin Compton amplitudes
Yohei Ema, Ting Gao, Wenqi Ke +2
We recursively construct tree-level electromagnetic and gravitational Compton amplitudes of higher-spin massive particles by the all-line transverse momentum shift. With three-poin…
Cancellation of one-loop correction to soft tensor power spectrum
Yohei Ema, Muzi Hong, Ryusuke Jinno +1
We demonstrate that there are no scale-invariant one-loop corrections to the superhorizon tensor perturbations from small-scale (potentially enhanced) scalar perturbations, irrespe…
Spontaneous Magnetogenesis at the Electroweak Phase Transition
Valerie Domcke, Yohei Ema, Teerthal Patel
Spontaneous CP violation during the electroweak phase transition can induce a twisting of the magnetic field configuration of Standard Model dumbbells, resulting in sizable interga…
Cutting rule for in-in correlators and cosmological collider
Yohei Ema, Kyohei Mukaida
We derive a cutting rule for equal-time in-in correlators including cosmological correlators based on Keldysh basis, which decomposes diagrams into fully retarded functions a…
Momentum shift and on-shell recursion relation for electroweak theory
Yohei Ema, Ting Gao, Wenqi Ke +3
We study the All-Line Transverse (ALT) shift which we developed for on-shell recursion of amplitudes for particles of any mass. We discuss the validity of the shift for general the…
Chiral properties of the nucleon interpolating current and -dependent observables
Yohei Ema, Ting Gao, Maxim Pospelov +1
We revisit the chiral properties of nucleon interpolating currents, and show that of the two leading order currents and , only two linear combinations trans…
Dark Matter Catalyzed Baryon Destruction
Yohei Ema, Robert McGehee, Maxim Pospelov +1
WIMP-type dark matter may have additional interactions that break baryon number, leading to induced nucleon decays which are subject to direct experimental constraints from proton…
Inflaton decay in No-Scale Supergravity and Starobinsky-like models
Yohei Ema, Marcos A. G. Garcia, Wenqi Ke +2
We consider the decay of the inflaton in Starobinsky-like models arising from either an theory of gravity or no-scale supergravity models. If Standard Model matter is…
Momentum shift and on-shell constructible massive amplitudes
Yohei Ema, Ting Gao, Wenqi Ke +3
We construct tree-level amplitude for massive particles using on-shell recursion relations based on two classes of momentum shifts: an all-line transverse shift that deforms moment…
Probing Earth-Bound Dark Matter with Nuclear Reactors
Yohei Ema, Maxim Pospelov, Anupam Ray
Strongly-interacting dark matter can be accumulated in large quantities inside the Earth, and for dark matter particles in a few GeV mass range, it can exist in large quantities ne…
Perturbatively including inhomogeneities in axion inflation
Valerie Domcke, Yohei Ema, Stefan Sandner
Axion inflation, i.e. an axion-like inflaton coupled to an Abelian gauge field through a Chern-Simons interaction, comes with a rich and testable phenomenology. This is particularl…
Cosmological Collider Signatures of Higgs- Inflation
Yohei Ema, Sarunas Verner
We study the cosmological collider signatures in the Higgs- inflation model. We consider two distinct types of signals: one originating from the inflaton coupling to Standard…
Muon spin force
Yohei Ema, Ting Gao, Maxim Pospelov
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…
Searching for axions with kaon decay at rest
Yohei Ema, Zhen Liu, Ryan Plestid
We describe a novel search strategy for axions (or hadronically coupled axion-like particles) in the mass range of . The search relies on kaon decay at…
Heavy Neutral Leptons from Stopped Muons and Pions
Yohei Ema, Zhen Liu, Kun-Feng Lyu +1
Stopped muons, which are generic in pion-at-rest experiments, can shed light on heavy neutral leptons (HNLs) in unexplored parameter spaces. If the HNL is lighter than the muon, th…
Zero Casimir Force in Axion Electrodynamics and the Search for a New Force
Yohei Ema, Masashi Hazumi, Hideo Iizuka +2
We point out that there is a stable configuration of metal plates where the Casimir force is vanishing in axion electrodynamics. We consider a concrete setup involving Weyl semimet…
Flavor-changing light bosons with accidental longevity
Yohei Ema, Zhen Liu, Kun-Feng Lyu +1
We consider a model with a complex scalar field that couples to or within the "longevity" window: in which and $l_2…
Reevaluation of heavy-fermion-induced electron EDM at three loops
Yohei Ema, Ting Gao, Maxim Pospelov
Motivated by improved limits on electric dipole moments (EDMs), we revisit the three-loop light-by-light mechanism that transmits violation from a heavy fermion to a light one…
Improved indirect limits on charm and bottom quark EDMs
Yohei Ema, Ting Gao, Maxim Pospelov
We derive indirect limits on the charm and bottom quark electric dipole moments (EDMs) from paramagnetic AMO and neutron EDM experiments. The charm and bottom quark EDMs generate $…
Transient phenomena in the axion assisted Schwinger effect
Valerie Domcke, Yohei Ema, Kyohei Mukaida
Particle production induced by a time-dependent background is well understood as the projection of the time-evolved initial state onto a set of final states. While the asymptotic i…