Stars and planets can be ideal playgrounds to discover dark matter. In this talk, I will review a range of dark matter searches using celestial objects, including exoplanets, solar-system planets, and our Sun. I will also discuss a new framework to describe what happens when dark matter is captured inside these objects, and the implications for dark matter search strategies.

Heavy quarks and their bound states are ideal probes of the medium formed in heavy ion collisions.  The resulting hierarchy of scales of in-medium heavy quarkonium makes the combined system ideally suited for treatment using nonrelativistic effective field theories and the formalism of open quantum systems (OQS).  My talk will consist of three parts: in the first, I will present an introduction to nonrelativistic QCD (NRQCD), potential NRQCD (pNRQCD), and the OQS formalism; in the second, I will present the derivation of the master equation governing the evolution of in-medium heavy quarkonium; and in the third, I will discuss solutions of the master equation and present recent phenomenological results for the nuclear modification factor and the elliptic flow compared against experimental measurements.

Classical field theories of scalars that are invariant under a U(1) symmetry can have non-perturbative soliton solutions called Q-balls: spherical bound states that are the energy minimum for a fixed U(1) charge Q. The underlying non-linear differential equations cannot be solved analytically, but I will present analytical approximations that work remarkably well and allow us to understand both ground and excited Q-ball states with ease. The global U(1) symmetry can also be promoted to a gauge symmetry, leading to gauged Q-balls and Q-shells; once again we can find exceptionally good analytic approximations to describe these objects and their stability.

I will summarize the current status of lattice QCD+QED calculations of the hadronic light-by-light and hadronic vacuum polarization (HVP) contributions to the muon g-2.  Special attention will be given to the consistency of different lattice HVP and dispersive HVP results.  I will conclude with an outlook of what we can expect from the field in the near future.

The QCD axion is one of the most compelling solutions of the strong CP problem. There are major current efforts into searching for ultralight axion dark matter, which is believed to be the only phenomenologically viable realization of the QCD axion. Visible axions with decay constants at or below the electroweak scale are believed to have been long excluded by laboratory searches. In this talk, I will revisit experimental constraints on QCD axions in the O(10 MeV) mass range and show that a specific variant of the QCD axion remains compatible with existing constraints. Specifically, the axion must (i) couple predominantly to the first generation of SM fermions; (ii) decay to e+e− with a short lifetime of less than 10^−13 s; and (iii) have suppressed isovector couplings, i.e., if it must be piophobic. Remarkably, these are precisely the properties required to explain recently observed anomalies in nuclear de-excitations of the Be-8 and He-4 nuclei, as well as the 2−3 sigma anomaly in the measurement of the neutral pion branching ratio to e+e-. I will discuss a variety of low-energy axion signatures, such as rare meson decays, nuclear de-excitations via axion emission, and axion production in e+e− annihilation and fixed target experiments.

Dark matter with light mass represents a challenge for direct detection as typical kinetic energy can be below 1 eV.  However, in some rare instances scattering on very energetic solar electrons can bring the DM particles to keV kinetic energies, opening the way for probing these models using the largest and cleanest Xe-based DM detectors. I describe our calculations and numerical simulations of the reflected flux and derive novel limits on light dark matter scattering on electrons. 

In this talk I will talk about my recent article where we propose a simpler way to combine the seesaw and the scotogenic approaches, by making dark matter the seed of neutrino mass generation within a low-scale seesaw mechanism. For definiteness we take the inverse seesaw as our template. I will discuss thoroughly both the possibilities of explicit as well as dynamical lepton number violation. For the case of dynamical lepton number violation I will discuss in some detail the phenomenology of invisible Higgs decays with majoron emission, as well as the phenomenology of scotogenic WIMP dark matter.

We present the first lattice-QCD calculation of the unpolarized strange and charm parton distribution functions using large-momentum effective theory (LaMET). We use a lattice ensemble with 2+1+1 flavors of highly improved staggered quarks (HISQ) generated by MILC collaboration, with lattice spacing a ≈ 0.12 fm and Mπ ≈ 310 MeV, and clover valence fermions with two valence pion masses: 310 and 690 MeV. We use momentum-smeared sources to improve the signal up to nucleon boost momentum Pz = 2.18 GeV,  and determine nonperturbative renormalization factors in RI/MOM scheme. We compare our lattice results with the matrix elements obtained from matching the PDFs from CT18NNLO and NNPDF3.1NNLO global fits. Our data support the assumptions of strange-antistrange and charm-anticharm symmetry that are commonly used in global PDF fits.