There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

https://biblio.ugent.be/publication/685594/file/1130605.pdf

Review of Particle Physics

http://risa.stanford.edu/teaching/362/particledarkmatter.pdf

Particle dark matter: Evidence, candidates and constraints

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

/pdf/the-observation-of-gravitational-waves-from-a-binary-black-58srpupgg9.pdf

The Observation of Gravitational Waves from a Binary Black Hole Merger

We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.

Gravitational Focusing and Substructure Effects on the Rate Modulation in Direct Dark Matter Searches

There are deep connections between supersymmetry and cosmology. Supersymmetry, actually supergravity or superstring theories,1 offers the hope of unifying all particle interactions. N=1 supersymmetry at “low” (with respect to the Planck scale) energies may produce a good phenomenology of particle physics while solving the gauge hierarchy problem in Grand Unified Theories (GUT). A viable supergravity model must also have an acceptable cosmology. For example, it must produce inflation, which is required not only to solve cosmological problems of the standard Big Bang model, such as the horizon, flatnessoldness, entropy problems and the production of density fluctuations. Inflation is also required to solve internal problems of the elementary particle models, for example to dilute the number of monopoles (or walls) in GUT’s or the number of gravitinos in minimal supergravity. An important constraint on supersymmetric models is to avoid the “entropy crisis” on (Polyonyi” problem). This is a strong constraint on fields coupled only gravitationally to matter (such as the gravitino or fields in the “hidden sector” of supergravity models) which on decay generate too large entropy at late times (e.g., after nucleosynthesis). On the other hand cosmology may need supersymmetry not only to provide the Theory of Everything. Inflation may require supersymmetry to produce very flat potentials, needed to get small enough density perturbations during inflation and maybe, to have inflation at all (at least in semiclassical descriptions).

Supersymmetry and the Early Universe

The channeling of the recoiling nucleus in crystalline detectors after a WIMP collision would produce a larger scintillation or ionization signal in direct detection experiments than otherwise expected. I present estimates of the importance of this effect in NaI, Si and Ge crystals, using analytic models developed from the 1960's onwards to describe channeling and blocking effects.

Ion-Channeling in Direct Dark Matter Crystalline Detectors

Talks given at the V Taller de Particulas y Campos (V-TPyC) and V Taller Latinoam. de Fenomenologia de las Interac. Fundam. (V-TLFIF), Puebla, Mexico, 10/30 - 11/3 1995. These lectures are devoted to elementary particle physicists and assume the reader has very little or no knowledge of cosmology and astrophysics. After a brief historical introduction to the development of modern cosmology and astro-particles in which the Hot Big Bang model is defined, the Robertson-Walker metric and the dynamics of the Friedmann-Robertson-Walker cosmology are discussed in section 2. In section 3 the main observational features of the Universe are reviewed, including a description of our neighbourhood, homogeneity and isotropy, the cosmic background radiation, the expansion, the age and the matter content of the Universe. A brief account of the thermal history of the Universe follows in section 4, and relic abundances are discussed in section 5. Section 6 is devoted to primordial nucleosynthesis, section 7 to structure formation in the Universe and section 8 to the possibility of detection of the dark matter in the halo of our galaxy.

Graciela B. Gelmini

Papers

Gravitational Focusing and Substructure Effects on the Rate Modulation in Direct Dark Matter Searches

Supersymmetry and the Early Universe

Ion-Channeling in Direct Dark Matter Crystalline Detectors

Cosmology and Astroparticles

Baryon asymmetry from Planck-scale physics