A
bstract
We discuss the phenomenology of right-handed charged currents in the frame-work of the Standard Model Effective Field Theory, in which they arise due to a single gauge-invariant ...dimension-six operator. We study the manifestations of the nine complex couplings of the
W
to right-handed quarks in collider physics, flavor physics, and low-energy precision measurements. We first obtain constraints on the couplings under the assumption that the right-handed operator is the dominant correction to the Standard Model at observable energies. We subsequently study the impact of degeneracies with other Beyond-the-Standard-Model effective interactions and identify observables, both at colliders and low-energy experiments, that would uniquely point to right-handed charged currents.
A
bstract
We investigate neutrinoless double beta decay (0
νββ
) in the presence of sterile neutrinos with Majorana mass terms. These gauge-singlet fields are allowed to interact with Standard-Model ...(SM) fields via renormalizable Yukawa couplings as well as higher-dimensional gauge-invariant operators up to dimension seven in the Standard Model Effective Field Theory extended with sterile neutrinos. At the GeV scale, we use Chiral effective field theory involving sterile neutrinos to connect the operators at the level of quarks and gluons to hadronic interactions involving pions and nucleons. This allows us to derive an expression for 0
νββ
rates for various isotopes in terms of phase-space factors, hadronic low-energy constants, nuclear matrix elements, the neutrino masses, and the Wilson coefficients of higher-dimensional operators. The required hadronic low-energy constants and nuclear matrix elements depend on the neutrino masses, for which we obtain interpolation formulae grounded in QCD and chiral perturbation theory that improve existing formulae that are only valid in a small regime of neutrino masses. The resulting framework can be used directly to assess the impact of 0
νββ
experiments on scenarios with light sterile neutrinos and should prove useful in global analyses of sterile-neutrino searches. We per- form several phenomenological studies of 0
νββ
in the presence of sterile neutrinos with and without higher-dimensional operators. We find that non-standard interactions involving sterile neutrinos have a dramatic impact on 0
νββ
phenomenology, and next-generation experiments can probe such interactions up to scales of
O
(100) TeV.
Effective field theory arguments suggest that if beyond the standard model (BSM) sectors contain new sources of CP violation that couple to QCD, these sources will renormalize the θ term and ...frustrate ultraviolet solutions to the strong CP problem. Simultaneously, they will generate distinctive patterns of low-energy electric dipole moments in hadronic, nuclear, atomic, and molecular systems. Observing such patterns thus provides evidence that strong CP is solved by an infrared relaxation mechanism. We illustrate the renormalization of θ and the collections of electric dipole moments generated in several models of BSM physics, confirming effective field theory expectations, and demonstrate that measurements of ratios of electric dipole moments at planned experiments can provide valuable input on the resolution of the strong CP problem.
We investigate neutrinoless double-beta decay (0νββ) in the minimal extension of the standard model of particle physics, the νSM, where gauge-singlet right-handed neutrinos give rise to Dirac and ...Majorana neutrino mass terms. We focus on the associated sterile neutrinos and argue that the usual evaluation of their contributions to 0νββ, based on mass-dependent nuclear matrix elements, is missing important contributions from neutrinos with ultrasoft and hard momenta. We identify the hadronic and nuclear matrix elements that enter the new contributions and calculate all relevant nuclear matrix elements for 136Xe using the nuclear shell model. Finally, we illustrate the impact on 0νββ rates in specific neutrino mass models and show that the new contributions significantly alter the 0νββ rate in most parts of the νSM parameter space.
We study the sensitivity of the proposed SHiP experiment to the LQD operator in R-parity violating supersymmetric theories. We focus on single neutralino production via rare meson decays and the ...observation of downstream neutralino decays into charged mesons inside the SHiP decay chamber. We provide a generic list of effective operators and decay width formulas for any lambda' coupling and show the resulting expected SHiP sensitivity for a widespread list of benchmark scenarios via numerical simulations. We compare this sensitivity to expected limits from testing the same decay topology at the LHC with ATLAS.
In this work, we compute the electromagnetic corrections to neutron β decay using a low-energy hadronic effective field theory. We identify new radiative corrections arising from virtual pions that ...were missed in previous studies. The largest correction is a percent-level shift in the axial charge of the nucleon proportional to the electromagnetic part of the pion-mass splitting. Smaller corrections, comparable to anticipated experimental precision, impact the β-ν angular correlations and the β asymmetry. We comment on implications of our results for the comparison of the experimentally measured nucleon axial charge with first-principles computations using lattice QCD and on the potential of β decay experiments to constrain beyond-the-standard-model interactions.
We investigate the interplay between the high- and low-energy phenomenology of C P -violating interactions of the Higgs boson with gauge bosons. For this purpose, we use an effective field theory ...approach and consider all dimension-six operators arising in so-called universal theories. We compute their loop-induced contributions to electric dipole moments and the C P asymmetry in B → Xsγ and compare the resulting current and prospective constraints to the projected sensitivity of the LHC. Low-energy measurements are shown to generally have a far stronger constraining power, which results in highly correlated allowed regions in coupling space—a distinctive pattern that could be probed at the high-luminosity LHC.
I present the calculation of parity- and time-reversal-violating moments of the nucleon and light nuclei, originating from the QCD
term and effective dimension-six operators. By applying chiral ...effective field theory these calculations are performed in a unified framework. I argue that measurements of a few light-nuclear electric dipole moments would shed light on the mechanism of parity and time-reversal violation.
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