Axions emerge naturally from the Peccei-Quinn (PQ) mechanism which addresses the absence of CP violation in QCD; the axions produced through the “vacuum realignment mechanism” are also a good cold dark matter (CDM) candidate. Traditional cavity haloscope experiments such as ADMX and HAYSTAC have focused on the ~1-10 µeV mass range, leaving the theoretically well motivated mass range of ~100 µeV unexplored.
The Daya Bay Reactor Neutrino Experiment consists of eight identically designed antineutrino detectors placed underground at different baselines from six 2.9 GWth nuclear reactors in China. With the largest sample of reactor antineutrino interactions to date, and a tight control of systematic uncertainties, the experiment has world-leading precision for the determination of two neutrino oscillation parameters and the characterization of antineutrino emission from commercial nuclear reactors.
Quantum mechanics is experiencing an experimental and theoretical renaissance. In this talk, we will discuss novel ways to use quantum mechanics and provide several experimental applications of quantum tomography for proton-proton and heavy-ion collision experiments at the CERN Large Hadron Collider. We will discuss application of this model-independent analysis technique for Z bosons, dijets and quarkonia. The first observation of an unexpected correlation of spin and momentum in the experimental data will also be presented.
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With an anticipated world population of over 9.5 billion by 2050, we face an unprecedented challenge to sustainably provide sufficient food, water, energy and healthcare. Convergence, the merging of previously distinct disciplines, has emerged as a powerful model with untold potential to drive a new cycle of innovation-based economic growth. Bringing together insights and discoveries from the life, engineering, computation and physical sciences holds the promise of accelerating discovery and the development of new technologies to meet the 21st century’s needs.
The physics of the time orientation of causation is more subtle than what it looks like superficially. For a long while it was reduced to a mere linguistic issue (a “cause” is just the term of a correlation that happens earlier, Hume). As emphasized by Russell, there is no time orientation in fundamental physics. But causation was later better understood as an essential notion in the context of an agent having choices, which after all is our own common context. This traces the time orientation of causation to the time orientation of agency.
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.
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.
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.
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.