89 research outputs found
Electric dipole moment constraints on CP-violating heavy-quark Yukawas at next-to-leading order
Electric dipole moments are sensitive probes of new phases in the Higgs
Yukawa couplings. We calculate the complete two-loop QCD anomalous dimension
matrix for the mixing of CP-odd scalar and tensor operators and apply our
results for a phenomenological study of CP violation in the bottom and charm
Yukawa couplings. We find large shifts of the induced Wilson coefficients at
next-to-leading-logarithmic order. Using the experimental bound on the electric
dipole moment of the neutron, we update the constraints on CP-violating phases
in the bottom and charm quark Yukawas.Comment: 30 pages, 9 figures; included contributions of Weinberg operator;
updated numeric
Electroweak effects in the extraction of the CKM angle from decays
The angle of the standard CKM unitarity triangle can be determined
from tree-level -meson decays essentially without hadronic uncertainties. We
calculate the second-order electroweak corrections for the modes
and show that their impact on the determination of could be enhanced
by an accidental cancellation of poorly known hadronic matrix elements.
However, we do not expect the resulting shift in to exceed
.Comment: 13 pages, 4 figures. Version as published in Phys.Lett.
Constraints on CP-violating Higgs couplings to the third generation
Discovering CP-violating effects in the Higgs sector would constitute an
indisputable sign of physics beyond the Standard Model. We derive constraints
on the CP-violating Higgs-boson couplings to top and bottom quarks as well as
to tau leptons from low-energy bounds on electric dipole moments, resumming
large logarithms when necessary. The present and future projections of the
sensitivities and comparisons with the LHC constraints are provided.
Non-trivial constraints are possible in the future, even if the Higgs boson
only couples to the third-generation fermions.Comment: 26 pages, 10 figures; typos corrected, version as published in JHE
From quarks to nucleons in dark matter direct detection
We provide expressions for the nonperturbative matching of the effective
field theory describing dark matter interactions with quarks and gluons to the
effective theory of nonrelativistic dark matter interacting with
nonrelativistic nucleons. We give the leading and subleading order expressions
in chiral counting. In general, a single partonic operator already matches onto
several nonrelativistic operators at leading order in chiral counting. Thus,
keeping only one operator at the time in the nonrelativistic effective theory
does not properly describe the scattering in direct detection. Moreover, the
matching of the axial--axial partonic level operator, as well as the matching
of the operators coupling DM to the QCD anomaly term, naively include momentum
suppressed terms. However, these are still of leading chiral order due to pion
poles and can be numerically important. We illustrate the impact of these
effects with several examples.Comment: 47 pages, 8 figures. Improved discussion, corrected typographical
errors, updated reference
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