arXiv subjects

Chaja Baruch

Publications and source records attributed to Chaja Baruch.

4 recordsLinked to original sources

arXiv2026

Blocking Mesogenesis

Mechanisms of Mesogenesis generate the baryon asymmetry and dark matter of the Universe through late-time decays of Standard Model mesons into baryons and dark matter states. Utilizing the CP violation in the meson systems themselves, the resulting baryon asymmetry is directly controlled by collider observables, the CP asymmetry $A_{CP}$, and the branching fraction for the meson decays. Experimental probes of these decays place strong constraints on the amount of $CP$ violation required, placing it well above observed limits in meson mixing. Additionally, strong lower bounds on the proton lifetime seemingly rule out Mesogenesis mechanisms which use $D$ mesons. In this work, we propose to circumvent these constraints by ``morphing'' the mass of the dark sector particles using a late-time phase transition. The change in mass of the final decay products kinematically excludes meson and proton decays, relaxing the constraints on the model parameter space.

hep-ph↗

arXiv2025

Searching for exotic scalars at fusion reactors

The energy created in deuterium-tritium fusion reactors originates from a high-intensity neutron flux interacting with the reactor's inner walls. The neutron flux can also be used to produce a self-sustaining reaction by lining the walls with lithium-rich `breeding blankets', in which a fraction of neutrons interacts with lithium, creating the tritium fuel. The high-intensity neutron flux can also result in the production of dark sector particles, feebly interacting light scalars or pseudoscalars, via nuclear transitions within the breeding blanket. We estimate the potential size of such dark sector flux outside the reactor, taking into account all current constraints, and consider possible detection methods at current and future thermonuclear fusion reactors. As a by-product, we also recast the SNO axion bound for a CP even scalar. We find that year-long searches at current and future reactors can set leading constraints on dark scalar -- and dark pseudoscalar -- nucleon couplings.

hep-ph↗

arXiv2024

Constraining CP violating nucleon-nucleon long range interactions in diatomic eEDM searches

The searches for CP violating effects in diatomic molecules, such as $\text{HfF}^+$ and ThO, are typically interpreted as a probe of the electron's electric dipole moment ($e\text{EDM}$), a new electron-nucleon interaction, and a new electron-electron interaction. However, in the case of a nonvanishing nuclear spin, a new CP violating nucleon-nucleon long range force will also affect the measurement. Here, we use the $\text{HfF}^+$ $e\text{EDM}$ search and derive a new bound on this hypothetical interaction, which is the most stringent from terrestrial experiments in the 1 eV-10 keV mass range. These multiple new physics sources motivate independent searches in different molecular species for CP violation at low energy that result in model independent bounds, which are insensitive to cancellation among them.

hep-ph↗

arXiv2022

Axial vectors in DarkCast

In this work, we explore new spin-1 states with axial couplings to the standard model fermions. We develop a data-driven method to estimate their hadronic decay rates based on data from $\tau$ decays and using SU(3)$_{\rm flavor}$ symmetry. We derive the current and future experimental constraints for several benchmark models. Our framework is generic and can be used for models with arbitrary vectorial and axial couplings to quarks. We have made our calculations publicly available by incorporating them into the DarkCast package, see https://gitlab.com/darkcast/releases.

hep-ph↗