We point out that the states required by the Lattice Weak Gravity Conjecture, along with certain ... more We point out that the states required by the Lattice Weak Gravity Conjecture, along with certain genericity conditions, imply the existence of non-vanishing kinetic mixing between massless Abelian gauge groups in the low-energy effective theory. We carry out a phenomenological estimate using a string-inspired probability distribution for the masses of superextremal states and compare the results to expectations from string theory and field theory, estimating the magnitude of kinetic mixing in each case. In the string case, we compute the kinetic mixing in an ensemble of 1858 MSSMlike heterotic orbifolds as well as in Type II supergravity on a Calabi-Yau manifold. From the field theory perspective, we consider compactifications of a 5D gauge theory. Finally, we discuss potential loopholes that can evade the bounds set by our estimates.
The CDF collaboration recently reported a new precise measurement of the W boson mass M W with a ... more The CDF collaboration recently reported a new precise measurement of the W boson mass M W with a central value significantly larger than the SM prediction. We explore the effects of including this new measurement on a fit of the Standard Model (SM) to electroweak precision data. We characterize the tension of this new measurement with the SM and explore potential beyond the SM phenomena within the electroweak sector in terms of the oblique parameters S, T and U. We show that the large M W value can be accommodated in the fit by a large, nonzero value of U , which is difficult to construct in explicit models. Assuming U = 0, the electroweak fit strongly prefers large, positive values of T. Finally, we study how the preferred values of the oblique parameters may be generated in the context of models affecting the electroweak sector at tree-and loop-level. In particular, we demonstrate that the preferred values of T and S can be generated with a real SU(2) L triplet scalar, the humble swino, which can be heavy enough to evade current collider constraints, or by (multiple) species of a singlet-doublet fermion pair. We highlight challenges in constructing other simple models, such as a dark photon, for explaining a large M W value, and several directions for further study.
We investigate non-relativistic quantum mechanical potentials between fermions generated by vario... more We investigate non-relativistic quantum mechanical potentials between fermions generated by various classes of QFT operators and evaluate their singularity structure. These potentials can be generated either by four-fermion operators or by the exchange of a scalar or vector mediator coupled via renormalizable or non-renormalizable operators. In the non-relativistic regime, solving the Schrödinger equation with these potentials provides an accurate description of the scattering process. This procedure requires providing a set of boundary conditions. We first recapitulate the procedure for setting the boundary conditions by matching the first Born approximation in quantum mechanics to the tree-level QFT approximation. Using this procedure, we show that the potentials are nonsingular, despite the presence of terms proportional to r−3 and ∇i∇jδ(~r). This surprising feature leads us to propose the Quantum Mechanics Swampland, in which the Landscape consists of non-relativistic quantum me...
A statistically significant excess of gamma rays has been reported and robustly confirmed in the ... more A statistically significant excess of gamma rays has been reported and robustly confirmed in the Galactic Center over the past decade. Large local dark matter densities suggest that this Galactic Center Excess (GCE) may be attributable to new physics, and indeed it has been shown that this signal is well-modelled by annihilations dominantly into $$ b\overline{b} $$ b b ¯ with a WIMP-scale cross section. In this paper, we consider Majorana dark matter annihilating through a Higgs portal as a candidate source for this signal, where a large CP-violation in the Higgs coupling may serve to severely suppress scattering rates. In particular, we explore the phenomenology of two UV completions, a singlet-doublet model and a doublet-triplet model, and map out the available parameter space which can give a viable signal while respecting current experimental constraints.
The ACME collaboration has recently announced a new constraint on the electron EDM, |d e | < 1... more The ACME collaboration has recently announced a new constraint on the electron EDM, |d e | < 1.1 × 10−29 e cm, from measurements of the ThO molecule. This is a powerful constraint on CP-violating new physics: even new physics generating the EDM at two loops is constrained at the multi-TeV scale. We interpret the bound in the context of different scenarios for new physics: a general order-of-magnitude analysis for both the electron EDM and the CP-odd electron-nucleon coupling; 1-loop SUSY, probing sleptons above 10 TeV; 2-loop SUSY, probing multi-TeV charginos or stops; and finally, new physics that generates the EDM via the charm quark or top quark Yukawa couplings. In the last scenario, new physics generates a “QULE operator” $$ \left({q}_f{\overline{\sigma}}^{\mu \nu }{\overline{u}}_f\right)\kern0.5em \cdotp \kern0.5em \left(\ell {\overline{\sigma}}_{\mu \nu}\overline{e}\right) $$ q f σ ¯ μ ν u ¯ f · ℓ σ ¯ μ ν e ¯ , which in turn generates the EDM through RG evolution. If the Q...
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Papers by Aditya Parikh