Studies of Prototype CsI(Tl) Crystal Scintillators for Low-Energy Neutrino Experiments

Crystal scintillators provide potential merits for the pursuit of low-energy low-background experiments. A CsI(Tl) scintillating crystal detector is being constructed to study low-energy neutrino physics at a nuclear reactor, while projects are underway to adopt this technique for dark matter searches. The choice of the geometrical parameters of the crystal modules, as well as the optimization of the read-out scheme, are the results of an R&D program. Crystals with 40 cm in length were developed. The detector requirements and the achieved performance of the prototypes are presented. Future prospects for this technique are discussed.Comment: 32 pages, 14 figure

Scale dependency of biocapacity and the fallacy of unsustainable development

Area-based information obtained from remote sensing and aerial photography is often used in studies on ecological footprint and sustainability, especially in calculating biocapacity. Given the importance of the modi fi able areal unit problem (MAUP; i.e. the scale dependency of area-based information), a compre- hensive understanding of how the changes of biocapacity across scales (i.e. the resolution of data) is pivotal for regional sustainable development. Here, we present case studies on the effect of spatial scales on the biocapacity estimated for two typical river basin and watershed in Northwest China. The analysis demonstrated that the area sizes of major land covers and subsequently biocapacity showed strong signals of scale dependency, with minor land covers in the region shrinking while major land covers expanding when using large-grain (low resolution) data. The relationship between land cover sizes and their change ratio across scales was shown to follow a logarithm function. The biocapacity estimated at 10 10 km resolution is 10% lower than the one estimated at 1 1 km resolution, casting doubts on many regional and global studies which often rely on coarse scale datasets. Our results not only suggest that fi ne-scale biocapacity estimates can be extrapolated from coarse-scale ones according to the speci fi c scale-dependent patterns of land covers, but also serve as a reminder that conclusions of regional and global un-sustainability derived from low-resolution datasets could be a fallacy due to the MAUP

Spin- and charge-density oscillations in spin chains and quantum wires

We analyze the spin- and charge-density oscillations near impurities in spin chains and quantum wires. These so-called Friedel oscillations give detailed information about the impurity and also about the interactions in the system. The temperature dependence of these oscillations explicitly shows the renormalization of backscattering and conductivity, which we analyze for a number of different impurity models. We are also able to analyze screening effects in one dimension. The relation to the Kondo effect and experimental consequences are discussed.Comment: Final published version. 15 pages in revtex format including 22 epsf-embedded figures. The latest version in PDF format is available from http://fy.chalmers.se/~eggert/papers/density-osc.pd

The σ\sigma pole in J/ψ→ωπ+π−J/\psi \to \omega \pi^+ \pi^-

Using a sample of 58 million $J/\psi$ events recorded in the BESII detector, the decay $J/\psi \to \omega \pi^+ \pi^-$ is studied. There are conspicuous $\omega f_2(1270)$ and $b_1(1235)\pi$ signals. At low $\pi \pi$ mass, a large broad peak due to the $\sigma$ is observed, and its pole position is determined to be $(541 \pm 39)$ - $i$ $(252 \pm 42)$ MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

Search for the Lepton Flavor Violation Processes J/ψ→J/\psi \to μτ\mu\tau and eτe\tau

The lepton flavor violation processes $J/\psi \to \mu\tau$ and $e\tau$ are searched for using a sample of 5.8$\times 10^7$ $J/\psi$ events collected with the BESII detector. Zero and one candidate events, consistent with the estimated background, are observed in $J/\psi \to \mu\tau, \tau\to e\bar\nu_e\nu_{\tau}$ and $J/\psi\to e\tau, \tau\to\mu\bar\nu_{\mu}\nu_{\tau}$ decays, respectively. Upper limits on the branching ratios are determined to be $Br(J/\psi\to\mu\tau)<2.0 \times 10^{-6}$ and $Br(J/\psi \to e\tau) < 8.3 \times10^{-6}$ at the 90% confidence level (C.L.).Comment: 9 pages, 2 figure

A Measurement of Psi(2S) Resonance Parameters

Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been measured in the vicinity of the Psi(2S) resonance using the BESII detector operated at the BEPC. The Psi(2S) total width; partial widths to hadrons, pi+pi- J/Psi, muons; and corresponding branching fractions have been determined to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)= (2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)= (97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%, respectively.Comment: 8 pages, 6 figure

Observation of the decay \psip\rar\kstark

Using 14 million $\psi(2S)$ events collected with the BESII detector, branching fractions of \psip\rar\kstarkpm and \kstarknn are determined to be: \calB(\psip\rar\kstarkpm)=(2.9^{+1.3}_{-1.7}\pm0.4)\times 10^{-5} and \calB(\psip\rar\kstarknn)=(13.3^{+2.4}_{-2.7}\pm1.9)\times 10^{-5}. The results confirm the violation of the "12%" rule for these two decay channels with higher precision. A large isospin violation between the charged and neutral modes is observed.Comment: 5 pages, 3 figure

Evidence of psi(3770) non-DD-bar Decay to J/psi pi+pi-

Evidence of $\psi(3770)$ decays to a non-${D \bar D}$ final state is observed. A total of $11.8 \pm 4.8 \pm 1.3$ \psi(3770) \to \PPJP events are obtained from a data sample of 27.7 $\rm {pb^{-1}}$ taken at center-of-mass energies around 3.773 GeV using the BES-II detector at the BEPC. The branching fraction is determined to be BF(\psi(3770) \to \PPJP)=(0.34\pm 0.14 \pm 0.09)%, corresponding to the partial width of \Gamma(\psi(3770) \to \PPJP) = (80 \pm 33 \pm 23) keV.Comment: 8 pages, 7 figures, Submitted to Physics Letters

A Study of J/psi-->gamma gamma V(rho,phi) Decays with the BESII Detector

Using a sample of $58\times 10^6$ $J/\psi$ events collected with the BESII detector, radiative decays $J/\psi\to\gamma\gamma V$, where $V=\rho$ or $\phi$, are studied. A resonance around 1420 MeV/c$^2$ (X(1424)) is observed in the $\gamma\rho$ mass spectrum. Its mass and width are measured to be $1424\pm 10(stat)\pm 11(sys)$ MeV/c$^2$ and $101.0\pm 8.8 \pm 8.8$ MeV/c$^2$, respectively, and its branching ratio $B(J/\psi\to \gamma X(1424)\to \gamma \gamma \rho)$ is determined to be $(1.07\pm0.17 \pm 0.11)\times 10^{-4}$. A search for $X(1424)\to \gamma\phi$ yields a 95% C.L. upper limit $B(J/\psi\to \gamma X(1424)\to \gamma\gamma \phi) < 0.82 \times 10^{-4}$.Comment: 10 pages, 5 figures, submitted to PL

Improved measurement of the branching ratio of J/psi-->K_S K_L

The branching ratio of J/psi-->K_S K_L is measured with improved precision to be B(J/psi-->K_S K_L) = (1.82\pm 0.04\pm 0.13)\times 10^{-4}. using J/psi data collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider. This result is used to test the perturbative QCD ``12%'' rule between psi(2S) and J/psi decays and to investigate the relative phase between the three-gluon and one-photon annihilation amplitudes in J/psi decays.Comment: 10 pages, 14 figures, 2 tables, submitted to Phys. Rev.