NPA Zoom Seminar, Kimmy Wu, SLAC/KIPAC, "Improved Constraint on Primordial Gravitational Waves with Delensing"

Inflation generically predicts a background of primordial gravitational waves, which generate a primordial B-mode component in the polarization of the cosmic microwave background (CMB). The measurement of such a B-mode signature would lend significant support to the paradigm of inflation. Observed B modes also contain a component from the gravitational lensing of primordial E modes, which can obscure the measurement of the primordial B modes.

NPA Zoom Seminar, Govert Nijs, MIT, "A Transverse Momentum Differential Global Analysis of Heavy Ion Collisions"

The understanding of heavy ion collisions and its quark-gluon plasma formation requires a complicated interplay of rich physics in a wealth of experimental data. In this work we compare for identified particles as a function of transverse momentum both the spectra and the anisotropic flow coefficients for both PbPb and pPb collisions. We do this in a model including a free streaming prehydrodynamic phase with variable velocity v_fs, thereby widening the scope of initial conditions. During the hydrodynamic phase we vary three new second order transport coefficients.

NPA Zoom Seminar, Zhilei Xu, MIT, "Precision Cosmology: from the CMB to 21-cm Observations"

Over the past decades, the discovery and characterization of the cosmic microwave background (CMB) have marked the beginning of precision cosmology. At lower redshifts, future 21-cm signals from neutral hydrogen atoms also have great potential for cosmological and astrophysical studies. Observing 21-cm signals at different frequency bands produces a tomographic view of the universe. These observations will transform our current understanding of cosmology, commencing the 21-cm precision cosmology.

NPA Zoom Seminar, Jean-Francois Paquet, Duke, "Constraining the Viscosities of QCD with Relativistic Heavy Ion Collisions"

Fluids can be characterized by macroscopic properties such as viscosities or an equation of state. While the macroscopic properties of everyday fluids are determined by the electromagnetic interaction, an ensemble of fluids encountered in astrophysics and nuclear physics is dominated by the strong nuclear interaction. Relativistic collisions of heavy nuclei, performed at the Large Hadron Collider and the Relativistic Heavy Ion Collider, concentrate sufficient energy at the point of impact to produce a strongly-coupled plasma of deconfined nuclear matter.

NPA Zoom Seminar, Ruby Byrne, University of Washington, "Measuring the Epoch of Reionization: Progress, Challenges, and Next Steps for High Redshift 21 cm Cosmology"

The 21 cm emission line from neutral hydrogen represents a promising observational probe of cosmological evolution. In particular, measuring the highly redshifted 21 cm emission from the Epoch of Reionization (EoR) will illuminate a crucial and currently poorly understood period in cosmological history. The EoR denotes the period when radiation from early galaxies and black holes ionized the intergalactic medium.

NPA Zoom Seminar, Ho San Ko, LBL, "Accessing Generalized Parton Distributions at Jefferson Lab"

An exciting scientific frontier is the 3-dimensional exploration of nucleon (and nuclear) structure: nuclear femtography. The study of Generalized Parton Distributions (GPDs) captures the images of the transverse position distributions of fast moving quarks. Therefore, they provide richer information about the nucleon structure than the well known form factors and parton distribution functions. GPDs are accessible via exclusive reactions, where all particles in the final state are identified.

NPA Zoom Seminar, Stefania Amodeo, Cornell University, "Halo gas thermodynamics from the CMB: results from the Atacama Cosmology Telescope DR5"

The thermodynamic properties of the ionized baryons in galaxies, groups, and clusters encode the effects of the assembly history and feedback processes that shape galaxy and cluster formation. These properties can be studied through the imprints that the scattering of cosmic microwave background (CMB) photons off the free-electron gas in galaxies and clusters leave on high resolution CMB maps: the thermal and kinematic Sunyaev-Zel’dovich effects.

NPA Zoom Seminar, Noah Kurinsky, KICP/Fermilab, "Modeling Interactions of MeV-Scale DM with Crystal Targets: Plasmons, Phonons, and Lattice Defects"

Direct searches for dark matter which targeted SUSY-motivated areas of parameter space employed well-studied nucleon interactions at keV to MeV energy scales to predict typical DM-nucleon interaction distributions. Much lighter DM, probed by a new generation of experiments sensitive to eV-scale energy deposits, however, rely instead on condensed matter effects to extract larger recoil energies from the DM than would be suggested by the simple elastic kinematics of heavier DM.

NPA Zoom Seminar, Jeff Martoff, Temple University, "The HUNTER Sterile Neutrino Search Experiment"

The HUNTER experiment (Heavy Unseen Neutrinos from Total Energy-momentum Reconstruction) is a search for sterile neutrinos with masses in the 20-300 keV range. The experiment uses a combination of AMO, nuclear and particle physics techniques to do kinematically complete missing mass reconstruction of neutrinos from 131-Cs electron capture decays. A magneto-optically trap (MOT) of 131-Cs atoms provides a pure sample of ~10^8 radioactive atoms suspended in EUHV with no inert material present.

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