Sensitivity of T2KK to the non-standard interaction in propagation

Assuming only the non-zero electron and tau neutrino components $\epsilon_{ee}$, $\epsilon_{e\tau}$, $\epsilon_{\tau\tau}$ of the non-standard matter effect and postulating the atmospheric neutrino constraint $\epsilon_{\tau\tau}=|\epsilon_{e\tau}|^2/(1+\epsilon_{ee})$, we study the sensitivity to the non-standard interaction in neutrino propagation of the T2KK neutrino long-baseline experiment. It is shown that T2KK can constrain the parameters $|\epsilon_{ee}|\lesssim 1$, $|\epsilon_{e\tau}|\lesssim 0.2$. It is also shown that if $|\epsilon_{e\tau}|$ and $\theta_{13}$ are large, then T2KK can determine the Dirac phase and the phase of $\epsilon_{e\tau}$ separately, due to the information at the two baselines. We also provide an argument that the components $|\epsilon_{\alpha\mu}|$ $(\alpha=e,\mu,\tau)$ must be small for the disappearance oscillation probability to be consistent with high-energy atmospheric neutrino data, which justifies our premise that these quantities are negligible.Comment: 29 pages, 25 figures, uses revtex4-1. Several places including typos revised. New references adde

Systematic limits on sin^2{2theta_{13}} in neutrino oscillation experiments with multi-reactors

Sensitivities to sin^2{2theta_{13}} without statistical errors (``systematic limit'') are investigated in neutrino oscillation experiments with multiple reactors. Using an analytical approach, we show that the systematic limit on sin^2{2theta_{13}} is dominated by the uncorrelated systematic error sigma_u of the detector. Even in an experiment with multi-detectors and multi-reactors, it turns out that most of the systematic errors including the one due to the nature of multiple sources is canceled as in the case with a single reactor plus two detectors, if the near detectors are placed suitably. The case of the KASKA plan (7 reactors and 3 detectors) is investigated in detail, and it is explicitly shown that it does not suffer from the extra uncertainty due to multiple reactors.Comment: 26 pages, 10 eps-files, revtex

Field Induced Multiple Reentrant Quantum Phase Transitions in Randomly Dimerized Antiferromagnetic S=1/2 Heisenberg Chains

The multiple reentrant quantum phase transitions in the $S=1/2$ antiferromagnetic Heisenberg chains with random bond alternation in the magnetic field are investigated by the density matrix renormalization group method combined with the interchain mean field approximation. It is assumed that the odd-th bond is antiferromagnetic with strength $J$ and even-th bond can take the values {\JS} and {\JW} ({\JS} > J > {\JW} > 0) randomly with probability $p$ and $1-p$, respectively. The pure version ($p=0$ and $p=1$) of this model has a spin gap but exhibits a field induced antiferromagnetism in the presence of interchain coupling if Zeeman energy due to the magnetic field exceeds the spin gap. For $0 < p < 1$, the antiferromagnetism is induced by randomness at small field region where the ground state is disordered due to the spin gap in the pure case. At the same time, this model exhibits randomness induced plateaus at several values of magnetization. The antiferromagnetism is destroyed on the plateaus. As a consequence, we find a series of reentrant quantum phase transitions between the transverse antiferromagnetic phases and disordered plateau phases with the increase of the magnetic field for moderate strength of interchain coupling. Above the main plateaus, the magnetization curve consists of a series of small plateaus and the jumps between them, It is also found that the antiferromagnetism is induced by infinitesimal interchain coupling at the jumps between the small plateaus. We conclude that this antiferromagnetism is supported by the mixing of low lying excited states by the staggered interchain mean field even though the spin correlation function is short ranged in the ground state of each chain.Comment: 5 pages, 8 figure

Spontaneous alloying in binary metal microclusters - A molecular dynamics study -

Microcanonical molecular dynamics study of the spontaneous alloying(SA), which is a manifestation of fast atomic diffusion in a nano-sized metal cluster, is done in terms of a simple two dimensional binary Morse model. Important features observed by Yasuda and Mori are well reproduced in our simulation. The temperature dependence and size dependence of the SA phenomena are extensively explored by examining long time dynamics. The dominant role of negative heat of solution in completing the SA is also discussed. We point out that a presence of melting surface induces the diffusion of core atoms even if they are solid-like. In other words, the {\it surface melting} at substantially low temperature plays a key role in attaining the SA.Comment: 15 pages, 12 fgures, Submitted to Phys.Rev.