We study the processes $e^+ e^-\to K^+ K^- \pi^+\pi^-\gamma$, $K^+K^-\pi^0\pi^0\gamma$ and $K^+ K^- K^+ K^-\gamma$, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232 \invfb of \babar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that the $K^+ K^- \pi^+\pi^-\gamma$ data can be compared with direct measurements of the $e^+ e^-\to K^+K^- \pipi$ reaction/ no direct measurements exist for the $e^+ e^-\to K^+ K^- \pi^0\pi^0$ or $\epem\to K^+ K^- K^+ K^-$ reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\phi(1020) f_{0}(980)$ and study its structure near threshold. In the charmonium region, we observe the $J/\psi$ in all three final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of $\BR_{Y(4260)\to\phi\pi^+\pi^-}\cdot\Gamma^{Y}_{ee}<0.4 \ev$ at 90% C.L.

Using data samples collected at center of mass energies of $\sqrt{s}$ = 4.009, 4.226, 4.257, 4.358, 4.416 and 4.599 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the isospin violating decay $Y(4260)\rightarrow J/\psi \eta \pi^{0}$. No signal is observed, and upper limits on the cross section $\sigma(e^{+}e^{-}\rightarrow J/\psi \eta \pi^{0})$ at the 90\% confidence level are determined to be 3.6, 1.7, 2.4, 1.4, 0.9 and 1.9 pb, respectively.

We have measured cross sections, rapidity and transverse momentum distributions, and vector meson polarization for the reactions pp→ ϱ o +anything, pp→ ω +charged particles, and pp → K ∗± + anything at incident laboratory momenta of 12 and 24 GeV/ c . We discuss various consequences of our results as well as possible connections with lepton pair production.

The reaction e^+e^- -> e^+e^- proton antiproton is studied with the L3 detector at LEP. The analysis is based on data collected at e^+e^- center-of-mass energies from 183 GeV to 209 GeV, corresponding to an integrated luminosity of 667 pb^-1. The gamma gamma -> proton antiproton differential cross section is measured in the range of the two-photon center-of-mass energy from 2.1 GeV to 4.5 GeV. The results are compared to the predictions of the three-quark and quark-diquark models.

Using the BES-II detector at the BEPC Collider, we measured the lowest order cross sections and the $R$ values ($R=\sigma^0_{e^+e^- \to {\rm hadrons}}/\sigma^0_{e^+e^- \to \mu^+\mu^-}$) for inclusive hadronic event production at the center-of-mass energies of 3.650 GeV, 3.6648 GeV and 3.773 GeV. The results lead to $\bar R_{uds}=2.224\pm 0.019\pm 0.089$ which is the average of these measured at 3.650 GeV and 3.6648 GeV, and $R=3.793\pm 0.037 \pm 0.190$ at $\sqrt{s}=3.773$ GeV. We determined the lowest order cross section for $\psi(3770)$ production to be $\sigma^{\rm B}_{\psi(3770)} = (9.575\pm 0.256 \pm 0.813)~{\rm nb}$ at 3.773 GeV, the branching fractions for $\psi(3770)$ decays to be $BF(\psi(3770) \to D^0\bar D^0)=(48.9 \pm 1.2 \pm 3.8)%$, $BF(\psi(3770) \to D^+ D^-)=(35.0 \pm 1.1 \pm 3.3)%$ and $BF(\psi(3770) \to D\bar{D})=(83.9 \pm 1.6 \pm 5.7)%$, which result in the total non-$D\bar D$ branching fraction of $\psi(3770)$ decay to be $BF(\psi(3770) \to {\rm non}-D\bar D)=(16.1 \pm 1.6 \pm 5.7)%$.

The total proton-proton cross section (excluding Coulomb scattering) has been measured at energies from 410 Mev up to 2.6 Bev, using external beams from the Cosmotron. Fast counting equipment was used to measure the attenuation of the beams through polyethylene, carbon, and liquid H2 absorbers. At each energy E, σp−p(E, Ω) was measured as a function of the solid angle Ω subtended by the rear counter at the center of the absorber. The total cross section σp−p was obtained by a least squares straight line extrapolation to Ω=0. The measured σp−p as a function of energy rises sharply from 26.5 mb at 410 Mev to 47.8 mb at 830 Mev and then remains approximately constant out to 1.4 Bev, above which energy it decreases gradually to about 42 mb at 2.6 Bev. Using the same equipment and procedure, we have also measured the D2O-H2O difference cross section, called "σp−n," for protons over the same energy range. From a comparison of "σp−n," and σp−p, with the n−p and n−d measurements of Coor et al. at 1.4 Bev, it is apparent that one nucleon is "shielded" by the other in the deuteron. This effect is not present at energies below 410 Mev. Comparing the measured p−p and "p−n" (corrected) cross sections with the results of other high-energy experiments, one may infer the following conclusions: (1) The sharp rise in σp−p from 400 to 800 Mev results from increasing single pion production, which may proceed through the T=32, J=32 excited nucleon state. (2) Above 1 Bev the inelastic (meson production) p−p cross section appears to be approximately saturated at 27-29 mb. (3) The rise in cross section for n−p interaction in the T=0 state, associated with the rise in double pion production, implies that double meson production also proceeds through the T=32 nucleon state. (4) The probable equality of σp−d and σn−d at 1.4 Bev implies the validity of charge symmetry at this energy.

Qausi-elastic ω production by ep scattering in the kinematic region 0.3. < Q 2 < 1.4 GeV 2 and 1.7 < W < 2.8 GeV was studied using a streamer chamber at DESY. The production angular distribution for γ V p → ω p has a strong non-peripheral component for W < 2 GeV. The ω production cross section falls by a factor of 4 as W changes from 1.7 to 2.8 GeV. In contrast the cross section for ω production with | t | < 0.5 GeV 2 is W independent between 1.7 and 2.8 GeV and for W > 2.0 GeV consistent in both W and Q 2 dependence with the predictions of a model based on one-pion exchange and diffraction.

We report values of $R = \sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$ for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

Using the data sets of 17.3 pb$^{-1}$ collected at $\sqrt{s}=$ 3.773 GeV and 6.5 pb$^{-1}$ collected at $\sqrt{s}=$ 3.650 GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 18 exclusive light hadron final states produced in $e^+e^-$ annihilation at the two energy points.

The reactions gamma gamma -> pi^+pi^-pi^+pi^- and gamma gamma -> pi^+pi^0pi^-pi^0 are studied with the L3 detector at LEP in a data sample collected at centre-of-mass energies from 161GeV to 209GeV with a total integrated luminosity of 698/pb. A spin-parity-helicity analysis of the rho^0 rho^0 and rho^+ rho^- systems for two-photon centre-of-mass energies between 1GeV and 3GeV shows the dominance of the spin-parity state 2+ with helicity 2. The contribution of 0+ and 0- spin-parity states is also observed, whereas contributions of 2- states and of a state with spin-parity 2+ and zero helicity are found to be negligible.