88 research outputs found

    Electric dipole moment constraints on CP-violating heavy-quark Yukawas at next-to-leading order

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    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

    Higher-Order Corrections to Precision Observables in Kaon Decays

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    Electroweak effects in the extraction of the CKM angle γ\gamma from B→DπB \to D \pi decays

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    The angle γ\gamma of the standard CKM unitarity triangle can be determined from tree-level BB-meson decays essentially without hadronic uncertainties. We calculate the second-order electroweak corrections for the B→DπB \to D \pi modes and show that their impact on the determination of γ\gamma could be enhanced by an accidental cancellation of poorly known hadronic matrix elements. However, we do not expect the resulting shift in γ\gamma to exceed ∣δγDπ/γ∣≲O(10−4)\big|\delta \gamma^{D\pi} /\gamma \big| \lesssim {\mathcal O}\big(10^{-4}\big).Comment: 13 pages, 4 figures. Version as published in Phys.Lett.

    Constraints on CP-violating Higgs couplings to the third generation

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    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

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    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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