Korea Institute of Science and Technology Information

About: Korea Institute of Science and Technology Information is a facility organization based out in Daejeon, South Korea. It is known for research contribution in the topics: Gravitational wave & LIGO. The organization has 1152 authors who have published 2319 publications receiving 93849 citations. The organization is also known as: Korea Institute of Science and Technology Information & KISTI.

Search of the Orion spur for continuous gravitational waves using a loosely coherent algorithm on data from LIGO interferometers

Abstract: We report results of a wideband search for periodic gravitational waves from isolated neutron stars within the Orion spur towards both the inner and outer regions of our Galaxy. As gravitational waves interact very weakly with matter, the search is unimpeded by dust and concentrations of stars. One search disk (A) is 6.87° in diameter and centered on 20^h10^m54.71^s+33°33′25.29′′, and the other (B) is 7.45° in diameter and centered on 8^h35^m20.61^s−46°49′25.151′′. We explored the frequency range of 50–1500 Hz and frequency derivative from 0 to −5×10^(−9) Hz/s. A multistage, loosely coherent search program allowed probing more deeply than before in these two regions, while increasing coherence length with every stage. Rigorous follow-up parameters have winnowed the initial coincidence set to only 70 candidates, to be examined manually. None of those 70 candidates proved to be consistent with an isolated gravitational-wave emitter, and 95% confidence level upper limits were placed on continuous-wave strain amplitudes. Near 169 Hz we achieve our lowest 95% C.L. upper limit on the worst-case linearly polarized strain amplitude h_0 of 6.3×10^(−25), while at the high end of our frequency range we achieve a worst-case upper limit of 3.4×10^(−24) for all polarizations and sky locations.

Measurements of branching fractions for B0→Ds+π- and B̄0→Ds+K

Abstract: We present improved measurements of the branching fractions for the decays B-0 -> D-s(+) pi(-) and (B) over bar (0) -> D-s(+) K- using a data sample of 657 X 10(6) B (B) over bar events collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric- energy e(+)e(-) collider. The results are B(B-0 -> D-s(+) pi(-)) = (1.99 +/- 0.26 +/- 0.18) X 10(-5) and B((B) over bar (0) -> D-s(+) K-) = (1.91 +/- 0.24 +/- 0.17) X 10(-5), where the uncertainties are statistical and systematic, respectively. Based on these results, we determine the ratio between amplitudes of the doubly Cabibbo suppressed decay B-0 -> D+pi(-) and the Cabibbo favored decay B-0 -> D-pi(+), R-D pi = [1.71 +/- 0.11(stat) +/- 0.09(syst) +/- 0.02(theo)]%, where the last term denotes the theory error.

Evidence for direct CP violation in B ±→ηh ± and observation of B0→ηK0

Abstract: We report measurements of the branching fractions and CP asymmetries for B(±)→ηh(±) (h=K or π) and the observation of the decay B(0)→ηK(0) from the final data sample of 772×10(6) B B pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured branching fractions are B(B(±)→ηK(±))=(2.12±0.23±0.11)×10(-6), B(B(±)→ηπ(±))=(4.07±0.26±0.21)×10(-6), and B(B(0)→ηK(0))=(1.27(-0.29)(+0.33)±0.08)×10(-6), where the last decay is observed for the first time with a significance of 5.4 standard deviations (σ). We also find evidence for CP violation in the charged B modes, A(CP)(B(±)→ηK(±))=-0.38±0.11±0.01 and A(CP)(B(±)→ηπ(±))=-0.19±0.06±0.01 with significances of 3.8 σ and 3.0 σ, respectively. For all measurements, the first and second uncertainties are statistical and systematic, respectively.

Exact greybody factors for the brane scalar field of five-dimensional rotating black holes

Abstract: We study scalar perturbations of the five-dimensional rotating black holes and find an exact solution giving exact description of the Hawking radiation. Mathematically, the full solution for this spin-zero field is expressed in terms of the prolate spheroidal wave function with complex parameters. By using the spheroidal joining factor, we write the corresponding boundary condition and greybody factors. We also check that the exact result reproduces the low frequency limit of the greybody factor and shows good agreement with the known numerical results.