P-even, CP-violating Signals in Scalar-Mediated Processes
Howard E. Haber, Venus Keus, Rui Santos
备注：
58 pages, 10 figures, 10 tables. One reference added in version 2. New footnote 15 and a number of additional references added in version 3. Clarifications added at the beginning of Section 4 and some references updated in version 4. A few typographical errors corrected in version 5, which now approximately matches the published version
Most studies of Higgs sector CP violation focus on the detection of CP-violating neutral Higgs-fermion Yukawa couplings, which yield P-odd, CP-violating phenomena. There is some literature on purely bosonic signatures of Higgs sector CP violation, where the simultaneous observation of three processes (suitably chosen) constitutes a signal of P-even CP violation. However, in the examples previously analyzed, some of the processes are strongly suppressed in the approximate Higgs alignment limit (corresponding to the existence of a Standard Model like Higgs boson as suggested by LHC data), in which case the proposed CP-violating signals are difficult to observe in practice. In this paper, we extend the existing literature by examining processes that do not vanish in the Higgs alignment limit and whose simultaneous observation would provide unambiguous evidence for scalar-mediated P-even CP violation. We assess the discovery potential of such signals at various future multi-TeV lepton (and $γγ$) colliders. The potential for detecting loop-induced P-even, CP-violating phenomena is also considered.
The projected reach of direct electroweakino searches at the HL-LHC ($\sqrt{s}=14~{\rm TeV}, ~3000~{\rm fb^{-1}}$ LHC) in the framework of simplified models with R-parity violating (RPV) operators: $λ_{112}^{\prime \prime}u^{c}d^{c}s^{c}$ and $λ_{113}^{\prime\prime}u^{c}d^{c}b^{c}$, is studied. Four different analysis channels are chosen: $Wh$ mediated $1l+2b+jets+\rm E{\!\!\!/}_T$, $Wh$ mediated $1l+2γ+jets+\rm E{\!\!\!/}_T$, $WZ$ mediated $3l+jets+\rm E{\!\!\!/}_T$ and $WZ$ mediated $3l+2b+jets+\rm E{\!\!\!/}_T$ and the projected exclusion/discovery reach of direct wino searches in these cha…
We consider the lepton-number-violating processes in $Λ_b$/$Λ_c$ decays mediated by on-shell GeV-scale sterile neutrino. We calculate the branching ratio for the following processes: $Λ_b^{0} \rightarrow \mathcal{B}^+ μ^{-}μ^- π^+$, where $\mathcal{B}^+$ is $Λ_c^+$ or proton, and $Λ_c^{+} \rightarrow Λμ^{+}μ^+ π^-$, as function of the mass of the sterile neutrino $m_N$ and the heavy-light mixing coefficient of the extended Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix $|U_{μN}|^2$. The effect of finite detector size is included in our calculation. After comparing the theoretical effective bran…
It is known that limits on baryon-violating nucleon decays do not, in general, imply corresponding suppression of $n - \bar n$ transitions. In the context of a model with fermions propagating in higher dimensions, we investigate a related question, namely the implications of limits on $ΔL=-1$ proton and bound neutron decays mediated by four-fermion operators for rates of nucleon decays mediated by $k$-fermion operators with $k =6$ and $k=8$. These include a variety of nucleon and dinucleon decays to dilepton and trilepton final states with $ΔL=-3, \ -2, \ 1$, and $2$. We carry out a low-energy…
$\mathcal{P}$, $\mathcal{T}$-violating axion-mediated interactions in RaOH molecule
St. Petersburg State University（圣彼得堡国立大学）；Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre ”Kurchatov Institute”（俄罗斯国家研究中心库尔恰托夫研究所下属的B.P.康斯坦丁诺夫圣彼得堡核物理研究所）
In the presence of P,T-violating interactions, the exchange of axion-like particles between electrons and nucleons in atoms and molecules induces electric dipole moments (EDMs) of atoms and molecules. We perform calculations of such axion-exchange-induced atomic EDMs using the relativistic Hartree-Fock-Dirac method including electron core polarisation (RPA) corrections. We present analytical estimates to explain the dependence of these induced atomic EDMs on the axion mass and atomic parameters. From the experimental bounds on the EDMs of atoms and molecules, including $^{133}$Cs, $^{205}$Tl, …
This paper investigates how the nonzero temperature affects the differential cross-section for mesons scattering in a Lorentz-violating extension of the scalar electrodynamics. We initially discuss some features of the model and extract the zero temperature Feynman rules. Temperature effects are introduced using the Thermo Field Dynamics (TFD) formalism. It is shown that the corrections induced on the meson scattering are very large in the high-temperature regime. Furthermore, our results also suggest that temperature effects may contribute to new constraints on the Lorentz-violating parameter…
Updated constraints on $\mathcal{T}$,$\mathcal{P}$-violating axionlike-particle-mediated electron-electron and electron-nucleus interactions from HfF$^+$ experiment
We compute the CP-violating (CPV) scalar axion coupling to nucleons in the framework of baryon chiral perturbation theory and we apply the results to the case of left-right symmetry. The correlated constraints with other CPV observables show that the predicted axion nucleon coupling is within the reach of present axion-mediated force experiments for $M_{W_R}$ up to $1000$ TeV.
We examine CP-violating effects on electroweak phase transition (EWPT) in the standard model with a complex singlet scalar focusing particularly on a scenario where additional scalars have masses close to 125 GeV. Such a high mass degeneracy makes collider signatures in the scenario standard model like, and current experimental data cannot distinguish them from the standard model predictions. We utilize a simplified scalar potential to understand impacts of CP violation on EWPT qualitatively. Then, one-loop effective potential with a thermal resummation is employed for full numerical evaluatio…
While the axion was originally introduced to wash out CP violation from strong interactions, new sources of CP violation beyond QCD might manifest themselves via a tiny scalar axion-nucleon component. The latter can be experimentally probed in axion-mediated force experiments, as suggested long ago by J.E. Moody and F. Wilczek. In the present note, I review the physical origin of CP-violating axion couplings and point out the special role of the QCD axion as a low-energy portal to high-energy sources of CP violation.
We have considered a model, originally proposed by Ma and Wegman, where the mixing pattern in neutrino sector is explained with three Higgs doublets, six Higgs triplets and $A_4$ symmetry. The mixing pattern is explained with the help of vacuum expectation values (VEVs) of the above mentioned doublets and triplets. In order to study about the VEVs of the scalar fields, we construct the full invariant scalar potential of this model. After minimizing this scalar potential, we have found that two Higgs triplets can acquire zero VEVs. In order to generate non-zero VEVs to all the six Higgs triplet…
