D^0-D^0bar mixing in \Upsilon(1S) \to D^0 D^0bar decay at Super-B

\Dz-\Dzb mixing and significant CP violation in the charm system may indicate the signature of new physics. In this study, we suggest that the coherent \DzDzb events from the decay of \Upsilon(1S) \to \Dz \Dzb can be used to measure both mixing parameters and CP violation in charm decays. The neutral $D$ mesons from $\Upsilon(1S)$ decay are strongly boosted, so that it will offer the possibility to measure the proper-time interval, $\Delta t$, between the fully-reconstructed \Dz and \Dzb. Both coherent and time-dependent information can be used to extract \Dz-\Dzb mixing parameters. The sensitivity of the measurement should be improved at B factories or super-B.Comment: 6 pages, 1 figure, this is the last version to appear in Phys. Rev.

Insights on the Next Generation WLAN: High Experiences (HEX)

Wireless local area network (WLAN) witnesses a very fast growth in the past 20 years by taking the maximum throughput as the key technical objective. However, the quality of experience (QoE) is the most important concern of wireless network users. In this article, we point out that poor QoE is the most challenging problem of the current WLAN, and further analyze the key technical problems that cause the poor QoE of WLAN, including fully distributed networking architecture, chaotic random access, awkward ``high capability'', coarse-grained QoS architecture, ubiquitous and complicated interference, ``no place'' for artificial intelligence (AI), and heavy burden of standard evolving. To the best of our knowledge, this is the first work to point out that poor QoE is the most challenging problem of the current WLAN, and the first work to systematically analyze the technical problems that cause the poor QoE of WLAN. We highly suggest that achieving high experiences (HEX) be the key objective of the next generation WLAN

Proposal of Direct Search for Strongly Bound States of ppbar, npbar Systems with High Intensity and Collective pbar beam

In this letter, we discuss the possibility to look for the direct evidence of the existence of the ppbar and npbar bound states. Measurement of the single \gamma ray from the ppbar and npbar systems at rest can directly confirm whether the X(1860) and X(1835) are the resonances which are strongly coupled to ppbar. In addition to the neutral candidate, a charged resonance $X^-$ is also proposed to be searched for in npbar channel. We find that the data from the Crystal Barrel experiment at LEAR/CERN can be used to confirm the X(1835) observed by BES Collaboration. The possibility of measuring the $\gamma$ spectrum below 100 MeV at the new experiment with cold high intensity \pbar beam at GSI is discussed. These new techniques can be used to probe the structure of the X(1860) and X(1835) in the future.Comment: Accepted by Mod. Phys. Lett.

About Detecting CP-Violating Processes in J/\psi\to \KzKzb Decay

Questions about detecting CP-violating decay process of $J/\psi\to K^0\bar{K}^0\to K_SK_S$ are discussed. Possible background and material regeneration effect are analyzed. The discussion can be directly extended to other vector quarkonium decays, like $\Upsilon$, $\psi (2S)$ and $\phi\to K_S K_S$.Comment: 5 pages, 2 figures, Late