I will discuss the direct detection of dark matter (DM) with polar materials, where single production of optical or acoustic phonons gives excellent reach to scattering of sub-MeV DM for both scalar and vector mediators. Using Density Functional Theory (DFT), we calculate the material-specific matrix elements, focusing on GaAs and sapphire, and show that DM scattering in an anisotropic crystal...
I will review limits on dark matter and dark sectors from indirect searches, with a particular emphasis on what we can learn from probes of the early universe. I will discuss the recent claim of a primordial 21cm absorption signal by the EDGES experiment, and its possible implications for dark-sector physics.
Gravity provides both the evidence for dark matter and all of our present knowledge about its properties. By understanding the detailed structure of gravitationally bound objects in our Universe, we can probe the particle physics of dark matter in a way that is completely orthogonal to the Earth-based high-energy physics searches for dark matter. Such efforts will require close collaboration...
The LIGO detection of gravitational waves has opened a new window on the universe. I will discuss how the process of superradiance, combined with gravitational wave measurements, makes black holes into nature's laboratories to search for new light bosons, from axions to dark photons. When a bosonic particle's Compton wavelength is comparable to the horizon size of a black hole, superradiance...
We propose using interferometry of circularly polarized light as a mechanism by which to test for axion dark matter. These interferometers differ from standard interferometers only by the addition of a few quarter waveplates to preserve the polarization of light upon reflection. We show that using current technology, interferometers can probe new regions of axion parameter space up to a couple...
I will argue that axion dark matter may be detectable through narrow radio lines emitted from neutron stars. Neutron star magnetospheres host both a strong magnetic field and a plasma frequency that increases towards the neutron star surface. As the axions pass through the magnetosphere, they can resonantly convert into radio photons when the plasma frequency matches the axion mass, making the...
Among the theoretical models addressing the dark matter problem, the category based on a secluded sector is attracting increasing interest. The PADME experiment, at the Laboratori Nazionali di Frascati (LNF) of INFN, is designed to be sensitive to the production of a low mass gauge boson A’ of a new U(1) symmetry holding for dark particles. This 'dark photon’ is weakly coupled to the photon of...
Abstract: I will show how ultra-high-resolution measurements of the gravitational lensing of the Cosmic Microwave Background (CMB) can be used to measure the small-scale matter power spectrum. A robust measurement of structure on scales below 10 kiloparsecs today (M < 10^9 solar masses) with lensing of the CMB requires a telescope with roughly 20 arcsecond resolution or better, and would...
Abstract: Various theories beyond the Standard Model possess weakly interacting sub-eV particles often referred to as WISPs. Such particles, if they exist, would mediate long-range forces between macroscopic bodies. Strong constraints exist on such ultralight bosons with scalar and vector couplings to fermions from “spin-independent” experiments involving unpolarized test bodies. In contrast,...
No-host Dinner
Sea Basin Restaurant
642 Route 25A, Rocky Point, NY
631-744-1643
October 3, 2018, 6:30 PM
Cost: $42/pp
Abstract: MiniBooNE has recently updated both their short baseline neutrino oscillation and sub-GeV dark matter analyses. Both results have strong implications for the dark sector. The oscillation analyses suggests the existence of at least one sterile neutrino, while the null results from the sub-GeV dark matter search have placed the most stringent limits to date, on the vector portal dark...
We set constraints on millicharged particles (mCPs) based on electron scattering data from MiniBooNE and the Liquid Scintillator Neutrino Detector (LSND). Both experiments are found to provide new (and leading) constraints in certain mCP mass windows: 5 − 35 MeV for LSND and 100 − 180 MeV for MiniBooNE. Furthermore, we provide projections for the ongoing Fermilab SBN program, the Deep...
Axion-like particles (ALPs) produced in the core of a neutron star can convert to photons in the magnetosphere, leading to possible signatures in the soft and hard X-ray emission from these sources. We study these signatures taking the magnetar SGR 1806-20 as an example. In particular, assuming ALP emission rates from the core that are just subdominant to neutrino emission, the parameter...
It is well known that light scalar fields present during inflation are coherently excited. We show that if the field couples to gravity in a non-minimal way, the fluctuations at large scales are suppressed with respect to the small scales ones. This fact allows for the field excitations to make a sizeable contribution to the energy density of the universe without generating too large...
We study the simplest model of a dark sector that forms structure via cooling, in analogy to the baryonic sector.
This dark sector is an asymmetric, sub-dominant component of dark matter, that consists of a dark electron and a dark photon.
The dark-electron perturbations collapse and fragment due to bremsstrahlung cooling, forming astronomical objects of varying size and compactness. These...
The New Experiments With Spheres-Gas (NEWS-G) is dedicated to the direct search for Dark Matter candidates in the 0.1 – 10 GeV range. The experiment uses the novel Spherical Proportional Counter detector, which exhibits a number of key features including: a) low energy thresholds, few tens of eV, owing to low detector capacitance independently of the volume and high gain operation; b) small...
We have all heard of the cloud and bubble chambers of course, and the latter in the context of direct WIMP dark matter detection even. However, no one has explored a 3rd phase transition, into solid, until now that is. This talk will introduce the snowball chamber, which utilizes a supercooled liquid, just purified water in the prototype. An incoming particle triggers nucleation in the liquid,...
Authors: Sankha S Chakrabarty and Pierre Sikivie
Caustic rings of dark matter with tricusp cross-section were predicted to lie in the galactic disk. In the self-similar evolution of the dark halo, their radii increase on cosmological time scales at a rate of order 1 kpc/Gyr. When a caustic ring passes through the orbit of a star, the orbit is strongly perturbed. We find that a star moving in...
I will review BaBar's searches for the direct production of new particles in the context of dark sector and other models. Such searches are a high priority for the early running period of Belle II. I will discuss the status of Belle II and the prospects of these searches.
