Masamichi Sakai

© 2016. The American Astronomical Society. All rights reserved..We present a search, using KamLAND, a kiloton-scale anti-neutrino detector, for low-energy anti-neutrino events that were coincident with the gravitational-wave events GW150914 and GW151226, and the candidate event LVT151012. We find no inverse beta-decay neutrino events within ±500 s of either GW signal. This non-detection is used to constrain the electron anti-neutrino fluence and the total integrated luminosity of the astrophysical sources.

© 2016. The American Astronomical Society. All rights reserved.In the late stages of nuclear burning for massive stars, the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. As the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. We find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinos from a star with a mass of 25 Mȯ at a distance less than 690 pc with 3σ significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community.

© 2015 American Physical Society.We report a measurement of the neutrino-electron elastic scattering rate of 862 keV Be7 solar neutrinos based on a 165.4 kt d exposure of KamLAND. The observed rate is 582±94-1, which corresponds to an 862-keV Be7 solar neutrino flux of ×109cm-2s-1, assuming a pure electron-flavor flux. Comparing this flux with the standard solar model prediction and further assuming three-flavor mixing, a νe survival probability of 0.66±0.15 is determined from the KamLAND data. Utilizing a global three-flavor oscillation analysis, we obtain a total Be7 solar neutrino flux of ×109cm-2s-1, which is consistent with the standard solar model predictions.

The concept of contingency is very much debated. In this paper, I’ll offer a novel interpretation of it in Dharmakīrti’s ontology, focusing on his treatment and understanding of vināśa which is, according to Dharmakīrti, not contingent and thus occurs necessarily to everything. I will do so by clarifying some important terms, motivating and explaining Dharmakīrti’s position, and analyzing firsthand some Dharmakīrtian debate excerpts with Nyāya and/or Vaiśeṣika philosophers as the main opponents. In the course of this, I will show that basically, for Dharmakīrti, contingency is tantamount to dependency, whereas Nyāya and/or Vaiśeṣika authors, e.g., Śrīdhara and Bhāsarvajña, claim that something can be dependent on something else and still be necessary.

Dharmottara, one of the most outstanding commentators of Dharmakīrti, re-uses arguments in the Pramāṇaviniścayaṭīkā, his broad commentary on Dharmakīrti’s Pramāṇaviniścaya, from his independent essay, the Kṣaṇabhaṅgasiddhi. By analyzing contents of re-used arguments in the Pramāṇaviniścayaṭīkā, this paper clarifies Dharmottara’s intention of paraphrasing his arguments in his commentarial work on Dharmakīrti. I argue that, in terms of content, such arguments are original and never fit into Dharmakīrti’s own system. It can be said that Dharmottara has a clear intention to display his new innovations not only in his independent monograph, but also in his commentarial work. For Dharmottara, a commentary on Dharmakīrti is a better place than an independent monograph for showing off his advanced notions, since it is only in a commentary that his ideas can stand out directly against those of Dharmakīrti. In this sense, Dharmottara writes his commentary strategically. At the end of the article I discuss the significance of composing independent monographs or essays in the intellectual history of medieval India in the case of Dharmottara