We present a purely gravitational infra-red-calculable production mechanism for dark matter (DM) . The source of both the DM relic abundance and the hot Standard Model (SM) plasma is a primordial density of micro black holes (BHs), which evaporate via Hawking emission into both the dark and SM sectors. The mechanism has four qualitatively different regimes depending upon whether the BH evaporation is 'fast' or 'slow' relative to the initial Hubble rate, and whether the mass of the DM particle is 'light' or 'heavy' compared to the initial BH temperature. For each of these regimes we calculate the DM yield, Y, as a function of the initial state and DM mass and spin. In the 'slow' regime Y depends on only the initial BH mass over a wide range of initial conditions, including scenarios where the BHs are a small fraction of the initial energy density. The DM is produced with a highly non-thermal energy spectrum, leading in the 'light' DM mass regime (~260 eV and above depending on DM spin) to a strong constraint from free-streaming, but also possible observational signatures in structure formation in the spin 3/2 and 2 cases. The 'heavy' regime (~1.2 × 108 GeV to MPl depending on spin) is free of these constraints and provides new possibilities for DM detection. In all cases there is a dark radiation component predicted.

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector.

We obtain the renormalization group improved expressions of the Wilson coefficients associated to the Oð1=m 3 Þ spin-dependent heavy quark effective theory Lagrangian operators, with leading logarithmic approximation, in the case of zero light quarks. We have employed the Coulomb gauge.

The refined swampland de Sitter conjecture (SdSC) is a proposed constraint on the form of the total potential in a theory including quantum gravity. According to this conjecture potentials possessing metastable de Sitter vacua are in the swampland of effective field theories that cannot descend from a theory with gravity. It is known that in the Standard Model (SM), as the quark masses and θ-parameter are varied, IR-calculable metastable states in QCD appear (for N > 2 light quarks) and we discuss in detail their properties. We argue that it is possible that the SdSC excludes the values of quark masses and θ for which these metastable states can arise, leading to a possible surprising connection between quantum gravity and aspects of low-energy flavor phenomenology. The observed values of the quark masses and QCD θ-parameter are consistent with the SdSC. If, in addition, as partially indicated by large-N c and semi-classical analysis, pure SU (3) Yang-Mills theory has metastable states at θ = 0 (this to our knowledge is not definitively known) then much of the a-priori SM parameter space might be eliminated. In particular, if quark Yukawa couplings are kept fixed, the limit of large electroweak vacuum expectation v EW > ∼ 50 TeV could be excluded by the SdSC, possibly shedding a new light on the hierarchy problem. We argue that these statements are robust against the addition of a quintessence field unless extreme fine-tuning is allowed.

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