121624088
GENERAL REVIEW OF BES PHYSICS, ACHIEVEMENT AND FUTURE
A general review of BES physics results are given. New results from BES on J/ψ, ψ(2S) and ψ(3770) decays are presented. Enhancement of the mass spectrum at the threshold is observed in the decay of J/ψ to . Analyzes of sigma and kappa signals are reported in J/ψ to ωπ+π- and J/ψ to respectively. Results of new ψ(2S) decay channels are reported and compared with 12% rule. Some results from ψ(3770) scanning and D decays are reported. The status of BEPCII/BESIII project is briefly reported.
179453560
NEW BES AND CLEO RESULTS
123211493
Exploring the feasibility of a separated function RFQ with mini-vane structure
The accelerating field in the conventional RFQ is originated by the surface modulation of the quadruple electrodes. However, the axial accelerating field generated in this way is quite limited. To enhance the energy gain as well as the focusing power, a post-RFQ accelerating structure called separated function RFQ (SFRFQ) was proposed (Progr. Nat. Sci. 12(1) (2002) 23), and its feasibility has been explored (Chin. Phys. 51(6) (2002)). The RF accelerating field in the SFRFQ structure mainly occurs at gaps between periodical cells, while the electrical quadruple field inside the cells provides the transverse focusing. It turns out that the overall performance can be improved considerably, comparing with that of conventional RFQ. The preliminary results of calculation and model measurements are presented and discussed in the paper.
39938475
Experimental Study of Long Coupled Helix Resonator
Experimental tests of a coupled normal temperature low a helix resonator with six-half-wavelength are described. The frequency shift and dynamic instability of the resonator are studied experimentally. The mechanical vibration caused by ponderomotive effect has been controlled. This resonator can run stably at a RF power of 50 KW , frequency of 27 MHz, duty factor of 1/6, and the maximum voltage gain is more than 1.1 MV. Some measures have been taken to increase the stability of the helix. The resonator tested is a model for heavy ion booster following a small van de graff accelerator.
178557411
THE STATUS OF BESIII PROJECT
124889910
Recent Beijing Spectroscopy (BES) results
AbstractRecent experimental results from Beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from J/ψ decays, and a number of new states are found or confirmed, including σ, κ, X(1835), ωφ threshold enhancement in J/ψ→γωφ, a broad resonance in J/ψ→K+K−π0, decay studies of ψ(2S) and χCJ, as well as the results of ψ(3770) non-D$$
\bar D
$$ decays. The current status of BEPCII/BESIII, the major upgrade of BEPC/BESII, is also reported.
119177216
Lepton Flavor Violating $\tau$ Decays in Two Higgs Doublet Model III
We study the lepton flavor violating processes of $\tau^-\to\mu^-PP$ decays with $PP=K^+K^-,K^0\bar{K}^0,\pi^+\pi^-,\pi^0\pi^0$ in the framework of two Higgs doublet model III by virtue of the Chiral Perturbation Theory. In this model, only three neutral Higgs bosons contribute to these decays. With the current experimental constraints, we show that (a) the contributions of $|\lambda_{uu(dd)}|$ term are very small for these four decays; (b) we get the correlation between $|\lambda_{ss}|$ and $|\lambda_{\tau\mu}|$. For $|\lambda_{\tau\mu}| \sim 10-400$, one has $|\lambda_{ss}|\sim 40-1$; (c) in the existing model parameter space, $Br(\tau^- \to \mu^- K^+K^-)$ could reach the order of ${\cal O}(10^{-8})$, but $Br(\tau \to \mu^- \pi^+\pi^-/\pi^0\pi^0)$ are too small to be observed.
119284944
Thermal fluctuations in viscous cosmology
In this Letter we investigate the power spectrum of thermal fluctuations in very early stage of viscous cosmology. When the state parameter as well as the viscous coefficient of a barotropic fluid is properly chosen, a scale invariant spectrum with large non-Gaussianity can be obtained. In contrast to the results previously obtained in string gas cosmology and holographic cosmology, we find the non-Gaussianity in this context can be k-independent such that it is not suppressed at large scale, which is expected to be testified in future observation.
18894825
On the progenitor of supernova 2001du in ngc 1365
Hubble Space Telescope (HST) WFPC2 archival images obtained years prior to the explosion of the Type II-plateau supernova (SN) 2001du in NGC 1365 previously have been analyzed to isolate the progenitor star. The SN site was located using precise astrometry applied to the HST images, with significant uncertainty, leaving three possible progenitor candidates. Images of the fading SN have recently become publicly available in the HST archive, allowing us to pinpoint the SN's exact location on the preexplosion images. We show that the SN occurred in very close proximity to one of the blue candidate stars, but we argue that this star is not the actual progenitor. Instead, the progenitor was not detected on the pre-SN images, and we constrain the progenitor's mass to be less than . This is consistent with previous constraints on the progenitor masses of other Type II-plateau SNe, suggesting that such SNe arise from the iron core collapse of massive stars at the lower extreme of the possible mass range.
117275575
The double charm decays of B Mesons in the mSUGRA model
Based on the low energy effective Hamiltonian with naive factorization, we calculate the branching ratios(BRs) and CP asymmetries (CPAs) for the twenty three double charm decays $B/B_s \to D^{(*)}_{(s)} D^{(*)}_{(s)}$ in both the standard model (SM) and the minimal supergravity (mSUGRA) model. Within the considered parameter space, we find that (a) the theoretical predictions for the BRs, CPAs and the polarization fractions in the SM and the mSUGRA model are all consistent with the currently available data within $\pm 2\sigma$ errors; (b) For all the considered decays, the supersymmetric contributions in the mSUGRA model are very small, less than $7\%$ numerically. It may be difficult to observe so small SUSY contributions even at LHC.
123608448
Experience of BESIII data production with local cluster and distributed computing model
The BES III detector is a new spectrometer which works on the upgraded high-luminosity collider, BEPCII. The BES III experiment studies physics in the tau-charm energy region from 2 GeV to 4.6 GeV . From 2009 to 2011, BEPCII has produced 106M ψ(2S) events, 225M J/ψ events, 2.8 fb−1 ψ(3770) data, and 500 pb−1 data at 4.01 GeV. All the data samples were processed successfully and many important physics results have been achieved based on these samples. Doing data production correctly and efficiently with limited CPU and storage resources is a big challenge. This paper will describe the implementation of the experiment-specific data production for BESIII in detail, including data calibration with event-level parallel computing model, data reconstruction, inclusive Monte Carlo generation, random trigger background mixing and multi-stream data skimming. Now, with the data sample increasing rapidly, there is a growing demand to move from solely using a local cluster to a more distributed computing model. A distributed computing environment is being set up and expected to go into production use in 2012. The experience of BESIII data production, both with a local cluster and with a distributed computing model, is presented here.