Breit-Wigner Enhancement of Dark Matter Annihilation

We point out that annihilation of dark matter in the galactic halo can be enhanced relative to that in the early universe due to a Breit-Wigner tail, if the dark matter annihilates through a pole just below the threshold. This provides a new explanation to the "boost factor" which is suggested by the recent data of the PAMELA, ATIC and PPB-BETS cosmic-ray experiments.Comment: 4 pages, 4 figure

"The Genesis and the Development of the Pre-war Japanese Stock Market"

This paper examines the development of the Tokyo Stock Exchange since its inception in 1878 to the mid-1930s. Special attention is paid to the increases in the number of listed stocks throughout this period. By the mid-1930s, the Tokyo Stock Exchange had grown to a market bigger (measured relative to GDP) than many contemporary stock exchanges in major economies. Even compared with the stock exchanges in major countries today, the pre-war Tokyo Stock Exchange was quite large. New listings in the spot market section of the Tokyo Stock Exchange were not restricted for most of this period. Our regression analysis reveals that many firms decided to list their stocks on the Tokyo Stock Exchange as they became older and bigger. The commercial code change in 1911, which increased the protection of outside shareholders, also had a positive impact on the listings on the Tokyo Stock Exchange. The Tokyo Stock Exchange reform of 1918 that aimed at standardization of the spot transactions increased the listings on the Exchange. The analysis also suggests that in the earlier period, there was a "home bias" that the companies located in the Eastern part of Japan (closer to the Tokyo Stock Exchange) were more likely to be listed in the Tokyo Stock Exchange, but the effect diminished after the Exchange reform of 1918.

The Genesis and the Development of the Pre-war Japanese Stock Market ?Published in "Economic Review (Keizai Kenkyu)", January 2005, v. 56, iss. 1, pp. 15-29. ?

This paper examines the development of the Tokyo Stock Exchange since its inception in 1878 to the mid-1930s. Special attention is paid to the increases in the number of listed stocks throughout this period. By the mid-1930s, the Tokyo Stock Exchange had grown to a market bigger (measured relative to GDP) than many contemporary stock exchanges in major economies. Even compared with the stock exchanges in major countries today, the pre-war Tokyo Stock Exchange was quite large. New listings in the spot market section of the Tokyo Stock Exchange were not restricted for most of this period. Our regression analysis reveals that many firms decided to list their stocks on the Tokyo Stock Exchange as they became older and bigger. The commercial code change in 1911, which increased the protection of outside shareholders, also had a positive impact on the listings on the Tokyo Stock Exchange. The Tokyo Stock Exchange reform of 1918 that aimed at standardization of the spot transactions increased the listings on the Exchange. The analysis also suggests that in the earlier period, there was a "home bias" that the companies located in the Eastern part of Japan (closer to the Tokyo Stock Exchange) were more likely to be listed in the Tokyo Stock Exchange, but the effect diminished after the Exchange reform of 1918.

Quest for the Quark-Gluon Plasma

Present status and future prospect of the quest for the quark-gluon plasma with untrarelativistic nuclear collisions are discussed.Comment: Invited talk given at Tokyo-Adelaide Joint Workshop on Quarks, Astrophysics, Space Physics, University of Tokyo, Jan.6 -10, 200

Price limits are not always bad : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Business Studies in Finance at Massey University, Albany, New Zealand, December 2006

Regulators impose price limits on daily price movements to protect investors from excessive volatility, but several empirical studies have cast serious doubt on the benefits of such mechanisms. Using a large cross-sectional sample combined with intraday data from the Tokyo Stock Exchange, this study finds evidence that partially supports conventional criticisms that price limits spread out volatility, delay price discovery, and interrupt trading activities. More importantly, the transaction data analysis reveals that price limits help to reduce order imbalance and improve information asymmetry, justifying the existence of price limits on the Tokyo Stock Exchange. JEL Classification: G10; G14 Keywords: Price limit; Order imbalance; Information asymmetry; Tokyo Stock Exchange

Do Bulls and Bears Move Across Borders? International Transmission of Stock Returns and Volatility as the World Turns

This paper investigates empirically how returns and volatilities of stock indices are correlated between Tokyo and New York. Intradaily data are used, so that daytime and overnight returns are defined for both markets. Tokyo daytime hours overlap with New York overnight hours, while New York daytime hours overlap with Tokyo overnight hours. We find that in general Tokyo (Mew York) daytime returns are significantly correlated with New York (Tokyo) overnight returns. This suggests that information revealed during the trading hours of one market has a global impact on the returns of the other market. One exception is that after the October 1987 Crash, the Tokyo overnight returns were not significantly affected by New York daytime returns. We propose and estimate a signal extraction model with GARCH processes to determine the global factor from daytime returns. This is the problem of setting the opening price of a domestic market conditional on the foreign daytime returns. We also investigate lagged return and volatility spillovers. Except for a lagged return spillover from New York to Tokyo for the period after the Crash, there are no significant lagged spillovers in returns or in volatilities.

Tokyo Axion Helioscope

The idea of a magnetic axion helioscope was first proposed by Pierre Sikivie in 1983. Tokyo axion helioscope was built exploiting its detection principle with a dedicated cryogen-free superconducting magnet and PIN photodiodes for x-ray detectors. Solar axions, if exist, would be converted into x-ray photons in the magnetic field. Conversion is coherently enhanced even for massive axions by filling the conversion region with helium gas. Its start up, search results so far and prospects are presented.Comment: 5 pages, 3 figures, AXIONS 201

Why Do Solar Neutrino Experiments Below 1 Mev

I discuss why we need solar neutrino experiments below 1 MeV. I also express my prejudices about the desired number and types of such experiments, emphasizing the importance of p-p solar neutrino experimentsComment: To be published in the proceedings of the Second International Workshop on Low Energy Solar Neutrinos, University of Tokyo, Tokyo, Japan, December 4 and 5, 2000 (World Scientific