Risk-sensitive analysis of subsistence adaptations is warranted when (i) outcomes are to some degree unpredictable and (ii) they have nonlinear consequences for fitness and/or utility. Both conditions are likely to be common among peoples studied by ecological anthropologists and archaeologists. We develop a general conceptual model of risk. We then review and summarize the extensive empirical literatures from biology and anthropology for methodological insights and for their comparative potential. Risk-sensitive adaptive tactics are diverse and they are taxonomically widespread. However, the anthropological literature rarely makes use of formal models of risk-sensitive adaptation, while the biological literature lacks naturalistic observations of risk-sensitive behavior. Both anthropology and biology could benefit from greater interdisciplinary exchange. © 1999 Plenum Publishing Corporation.

Using a sample of 3.8 M ψ(2S) events accumulated with the BES detector, the process ψ(2S) →π+π-J/ψ is studied. The angular distributions are compared with the general decay amplitude analysis of Cahn. We find that the dipion system requires some D wave amplitude, as well as S wave. On the other hand, the J/ψ-(π+π-) relative angular momentum is consistent with being pure S wave. The decay distributions have been fit to heavy quarkonium models, including the Novikov-Shifman model. This model, which is written in terms of the parameter κ, predicts that D wave pions should be present. We determine κ=0.183 ±0.002±0.003 based on the joint mππ-cos θπ* distribution. The fraction of D wave amplitude as a function of mππ is found to decrease with increasing mππ, in agreement with the model. We have also fit the Mannel-Yan model, which is another model that allows D wave pions. ©2000 The American Physical Society.

The processes ψ(2S) → I π+ π−, γK+ K−, and γpp¯ have been studied using a sample of 3.79 × 106 ψ(2S) decays. We determine the total width of the χc0 to be γtotχc0 = 14.3 ± 2.0 ± 3.0 MeV. We present the first measurement of the branching fraction B(χc0 → pp¯) = (15.9 ± 4.3 ± 5.3) × 10−5, where the first error is statistical and the second one is systematic. Branching fractions of χc0, 2 → π+ π− and K+ K− are also reported. © 1998 American Physical Society.

Radiative decays of the radially excited charmonium resonance, (Formula presented) into (Formula presented) (Formula presented) and (Formula presented) final states have been measured in a sample of (Formula presented) (Formula presented) events collected by the BES Collaboration. The branching ratios (Formula presented) and (Formula presented) are obtained. When compared to the corresponding radiative (Formula presented) decays, the observed (Formula presented) radiative decay rates into (Formula presented) and (Formula presented) are consistent with the prediction of the “12%” rule. © 2003 The American Physical Society.

The cross section for charmed meson production at √s=4.03 and 4.14 GeV has been measured with the Beijing Spectrometer. The measurement was made using 22.3 pb-1 of e+e- data collected at 4.03 GeV and 1.5 pb-1 of e+e- data collected at 4.14 GeV. Inclusive observed cross sections for the production of charged and neutral D mesons and momentum spectra are presented. Observed cross sections were radiatively corrected to obtain tree level cross sections. Measurements of the total hadronic cross section are obtained from the charmed meson cross section and an extrapolation of results from below the charm threshold. ©2000 The American Physical Society.

A search is performed for the production of the (Formula presented) in (Formula presented) annihilation at a center-of-mass energy of 4.03 GeV using the BES detector operated at the Beijing Electron Positron Collider (BEPC). The kinematic features of the reconstructed (Formula presented) signal are consistent with its being produced only in association with an energetic photon resulting from initial state radiation (ISR). Limits are placed on (Formula presented) production from the decay of unknown charmonia or metastable hybrids that might be produced in (Formula presented) annihilations at 4.03 GeV. Under the assumption that the observed cross section for (Formula presented) production is due entirely to ISR, the partial width (Formula presented) of the (Formula presented) is measured to be (Formula presented). © 1998 The American Physical Society.

The absolute inclusive semileptonic branching fraction of the [Formula presented] meson has been measured based on [Formula presented] of [Formula presented] collision data collected with the Beijing Spectrometer at [Formula presented] At this energy, the [Formula presented] are produced in pairs: [Formula presented] We reconstructed [Formula presented] [Formula presented] events in five hadronic decay modes. In the recoil system of these events, several [Formula presented] inclusive semileptonic decays were observed and the branching fraction is estimated to be [Formula presented] © 1997 The American Physical Society.

A data-driven energy scan in the immediate vicinity of the τ pair production threshold has been performed using the Beijing Spectrometer at the Beijing Electron-Positron Collider. Approximately 5pb-1 of data, distributed over 12 scan points, have been collected. A previous mass value for the τ lepton, obtained using only the eµ final state, has been published. In this paper, the final BES result on the mass measurement is presented. The analysis is based on the combined data from the ee, eµ, eh, µµ, µh, and hh final states, where h denotes a charged Π or K. A maximum likelihood fit to the τ pair production cross section data yields the value mT=1776.96-0.21 -0.17+0.18+0.25. © 1995 The American Physical Society.

The decays of the ψ(2S) into vector plus tensor meson final states have been studied for the first time using the BES detector. We determine upper limits on branching fractions for ψ(2S) decays into ωf2, ρa2, K*0K*02 + c.c., and φf'2(1525) that are, in each case, significantly smaller than the corresponding branching fractions for the J/ψ meson, scaled according to the expectations of perturbative QCD. © 1998 The American Physical Society.

Using a sample of 3.8 M (Formula presented) events accumulated with the BES detector, the process (Formula presented) is studied. The angular distributions are compared with the general decay amplitude analysis of Cahn. We find that the dipion system requires some D wave amplitude, as well as S wave. On the other hand, the (Formula presented) relative angular momentum is consistent with being pure S wave. The decay distributions have been fit to heavy quarkonium models, including the Novikov-Shifman model. This model, which is written in terms of the parameter (Formula presented) predicts that D wave pions should be present. We determine (Formula presented) based on the joint (Formula presented) distribution. The fraction of D wave amplitude as a function of (Formula presented) is found to decrease with increasing (Formula presented) in agreement with the model. We have also fit the Mannel-Yan model, which is another model that allows D wave pions. © 2000 The American Physical Society.