A Thousand Invisible Cords Binding Astronomy and High-Energy Physics

The traditional realm of astronomy is the observation and study of the largest objects in the Universe, while the traditional domain of high-energy physics is the study of the smallest things in nature. But these two sciences concerned with opposite ends of the size spectrum are, in Muir's words, bound fast by a thousand invisible cords that cannot be broken. In this essay I propose that collaborations of astronomers and high-energy physicists on common problems are beneficial for both fields, and that both astronomy and high-energy physics can advance by this close and still growing relationship. Dark matter and dark energy are two of the binding cords I will use to illustrate how collaborations of astronomers and high-energy physicists on large astronomical projects can be good for astronomy, and how discoveries in astronomy can guide high-energy physicists in their quest for understanding nature on the smallest scales. Of course, the fields have some different intellectual and collaborative traditions, neither of which is ideal. The cultures of the different fields cannot be judged to be right or wrong; they either work or they don't. When astronomers and high-energy physicists work together, the binding cords can either encourage or choke creativity. The challenge facing the astronomy and high-energy physics communities is to adopt the best traditions of both fields. It is up to us to choose wisely.Comment: Why "Fundamentalist" Physics Is Good for Astronomy (in response to the paper of Simon White, arXiv:0704.2291

Di-jet hadron pair correlation in a hydrodynamical model with a quenching jet

In jet quenching, a hard QCD parton, before fragmenting into a jet of hadrons, deposits a fraction of its energy in the medium, leading to suppressed production of high-$p_T$ hadrons. Assuming that the deposited energy quickly thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP fluid. Hydrodynamic evolution and subsequent particle emission depend on the jet trajectories. Azimuthal distribution of excess $\pi^-$ due to quenching jet, averaged over all the trajectories, reasonably well reproduce the di-hadron correlation as measured by the STAR and PHENIX collaboration in central and in peripheral Au+Au collisions.Comment: 5 pages, 4 figures. Some minor corrections are made in the revised manuscrip

Spectrum of Gravitational Waves in Krein Space Quantization

The main goal of this paper is to derive the primordial power spectrum for the scalar perturbations generated as a result of quantum fluctuations during an inflationary pe- riod by an alternative approach of field quantization[1-3]. Formulas are derived for the gravitational waves, special cases of which include power law inflation and inflation in the slow roll approximation, in Krein space quantization.Comment: 6 pages, published in MPL

Particle-Antiparticle Asymmetry Due to Non-Renormalizable Effective Interactions

We consider a model for generating a particle-antiparticle asymmetry through out-of-equilibrium decays of a massive particle due to non-renormalizable, effective interactions.Comment: preliminary version, 38 pages; LaTeX source, epsf.sty and EPS files included in tar archiv

Blunting the Spike: the CV Minimum Period

The standard picture of CV secular evolution predicts a spike in the CV distribution near the observed short-period cutoff P_0 ~ 78 min, which is not observed. We show that an intrinsic spread in minimum (`bounce') periods P_b resulting from a genuine difference in some parameter controlling the evolution can remove the spike without smearing the sharpness of the cutoff. The most probable second parameter is different admixtures of magnetic stellar wind braking (at up to 5 times the GR rate) in a small tail of systems, perhaps implying that the donor magnetic field strength at formation is a second parameter specifying CV evolution. We suggest that magnetic braking resumes below the gap with a wide range, being well below the GR rate in most CVs, but significantly above it in a small tail.Comment: 5 pages, 4 figures; accepted for publication in MNRA

The small mixing angle θ13\theta_{13} and the lepton asymmetry

We present the correlation of low energy CP phases, both Dirac and Majorana, and the lepton asymmetry for the baryon asymmetry in the universe, with a certain class of Yukawa matrices that consist of two right-handed neutrinos and include one texture zero in themselves. For cases in which the amount of the lepton asymmetry $Y_L$ turns out to be proportional to $\theta_{13}^2$, we consider the relation between two types of CP phases and the relation of $Y_L$ versus the Jarlskog invariant or the amplitude of neutrinoless double beta decay as $\theta_{13}$ varies.Comment: 17 pages, 14 figures, information for figures added, version published in PR

A fully relativistic lattice Boltzmann algorithm

Starting from the Maxwell-Juettner equilibrium distribution, we develop a relativistic lattice Boltzmann (LB) algorithm capable of handling ultrarelativistic systems with flat, but expanding, spacetimes. The algorithm is validated through simulations of quark-gluon plasma, yielding excellent agreement with hydrodynamic simulations. The present scheme opens the possibility of transferring the recognized computational advantages of lattice kinetic theory to the context of both weakly and ultra-relativistic systems.Comment: 12 pages, 8 figure

Further Considerations on the CP Asymmetry in Heavy Majorana Neutrino Decays

We work out the thermodynamic equations for the decays and scatterings of heavy Majorana neutrinos including the constraints from unitarity. The Boltzmann equations depend on the CP asymmetry parameter which contains both, a self-energy and a vertex correction. At thermal equilibrium there is no net lepton asymmetry due to the CPT theorem and the unitarity constraint. We show explicitly that deviations from thermal equilibrium create the lepton asymmetry.Comment: 16 pages, LaTeX, 1 eps figure, 1 ps figur

Leptogenesis with Dirac Neutrinos

We describe a "neutrinogenesis" mechanism whereby, in the presence of right-handed neutrinos with sufficiently small pure Dirac masses, (B+L)-violating sphaleron processes create the baryon asymmetry of the Universe, even when B=L=0 initially. It is shown that the resulting neutrino mass constraints are easily fulfilled by the neutrino masses suggested by current experiments. We present a simple toy model which uses this mechanism to produce the observed baryon asymmetry of the Universe. (PostScript Errors corrected in latest Version).Comment: 4 pages, Latex (using amsmath,feynmp,graphicx), 4 figure