Related papers: Limits on a CP-violating scalar axion-nucleon inte…
We report on a neutron particle physics experiment, which provides for the first time an upper limit on the strength of an axial coupling constant for a new light spin 1 boson in the millimeter range. Such a new boson would mediate a new…
We explore CP violating aspects in the Higgs sector of models where new vectorlike quarks carry Yukawa couplings mainly to the third generation quarks of the Standard Model. We point out that in the simplest model, Higgs CP violating…
One of the Sakharov's condition for baryogenesis is the violation of both C and CP. In the Standard Model, gauge interactions break maximally C, but CP is only broken through the Yukawa couplings in the poorly understood scalar sector. In…
We derive supernova (SN) bounds on muon-philic bosons, taking advantage of the recent emergence of muonic SN models. Our main innovations are to consider scalars $\phi$ in addition to pseudoscalars $a$ and to include systematically the…
Hidden sector particles with sub-GeV masses like hidden U(1) gauge bosons, the NMSSM CP-odd Higgs, and other axion-like particles are experimentally little constrained as they interact only very weakly with the visible sector. For masses…
We investigate the implications of spontaneous CP-violation in the general two Higgs doublet model, which leads to a non-decoupling structure of the Higgs sector. All the masses of the Higgs bosons are purely determined by the vacuum…
We study CP violation in a multi-Higgs doublet model based on a $S_3 \times Z_3$ horizontal symmetry. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings; and b) CP violation due to…
The search for axions sits at the intersection of solving critical problems in fundamental physics, including the strong CP problem in QCD, uncovering the nature of dark matter, and understanding the origin of the universe's…
Ultra-high energy cosmic rays and neutrinos probe energies far above the weak scale. Their usefulness might appear to be limited by astrophysical uncertainties; however, by simultaneously considering up- and down-going events, one may…
It is well known that supersymmetry (SUSY) gives neutron and electron electric dipole moments ($d_n$ and $d_e$) which are too large by about $10^{3}$. If we assume a SUSY model cannot contain fine-tunings or large mass scales, then one must…
We used a torsion pendulum and rotating attractor with 20-pole electron-spin distributions to probe dipole-dipole interactions mediated by exotic pseudo-Goldstone bosons with $m_{\rm b}\leq 500 \; \mu$eV and coupling strengths up to 14…
We discuss signals for CP-violation in $\mu^+ \mu^- \to \tilde \tau_i^- \tilde \tau_j^+$, where $i,j = 1,2$ label the two scalar $\tau$ mass eigenstates. We assume that these reactions can proceed through the production and decay of the…
The exchange of light pseudoscalar quanta between fermions leads to long-range spin-dependent forces in order g^2, where g is the pseudoscalar-fermion coupling constant. We demonstrate that laboratory bounds on the Yukawa couplings of…
We study the possibility of a large CP/T-violation in lepton pair production in the collisions of polarized protons at RHIC-BNL. We propose the single transverse spin asymmetry which quantifies the possible CP/T-violating effect in this…
We consider the scalar-tensor theories of gravity extended by the pseudoscalar couplings to matter and gauge fields and derive constraints on the CP-odd combinations of scalar and pseudoscalar couplings from laboratory spin precession…
Axions and other light particles appear ubiquitously in physics beyond the Standard Model, with a variety of possible couplings to ordinary matter. Cosmology offers a unique probe of these particles as they can thermalize in the hot…
General neutrino-scalar couplings appear in many extensions of Standard Model. We can probe these neutrino-scalar couplings by leptonic decay of mesons and from heavy neutrino search. Our analysis improves the present limits to…
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…
The phenomenological constraints on extra neutral gauge bosons at present and at future colliders are reviewed. Special attention is paid to the influence of radiative corrections, systematic errors, and kinematic cuts on the Z'…
If axion simultaneously has the scalar couplings to the nucleons and pseudo-scalar couplings to the electrons, it may mediate a $\mathcal{P}$, $\mathcal{T}$-violating interaction between the electronic shell and nuclei in the molecules. The…