Open Access

The cross section of the process e+e-→π+D0D*- for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. [...]

Based on (4.48±0.03)×108  ψ(3686) events, collected with the BESIII detector at the BEPCII storage ring, five hc hadronic decays are searched for via the process ψ(3686)→π0hc. Three of them, hc→p¯pπ+π−, π+π−π0, and 2(π+π−)π0, are observed for the first time with significances of 7.4σ, 4.6σ, and 9.1σ, and their branching fractions are determined to be (2.89±0.32±0.55)×10−3, (1.60±0.40±0.32)×10−3, and (7.44±0.94±1.52)×10−3, respectively, where the first uncertainties are statistical and the second systematic. [...]

This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like X(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. [...]

We provide an explicit expression for the strong magnetic field limit of the Heisenberg-Euler effective Lagrangian for both scalar and spinor quantum electrodynamics. To this end, we show that the strong magnetic field behavior is fully determined by one-particle reducible contributions discovered only recently. [...]

Scalar and fermionic particle pair production in rotating electric fields is investigated in the nonperturbative multiphoton regime. Angular momentum distribution functions in above-threshold pair production processes are calculated numerically within quantum kinetic theory and discussed on the basis of a photon absorption model. [...]

We study single, double and higher-order nonlinear Compton scattering where an electron interacts nonlinearly with a high-intensity laser and emits one, two or more photons. We study, in particular, how double Compton scattering is separated into one-step and two-step parts, where the latter is obtained from an incoherent product of two single-photon emissions. [...]

We report on experimental results in a new regime of relativistic light-matter interaction employing midinfrared (3.9-mu m wavelength) high-intensity femtosecond laser pulses. In the laser-generated plasma, electrons reach relativistic energies already for rather low intensities due to the fortunate lambda(2) scaling of the kinetic energy with the laser wavelength. [...]