4 research outputs found
Measurement of azimuthal asymmetries in inclusive charged dipion production in annihilations at = 3.65 GeV
We present a measurement of the azimuthal asymmetries of two charged pions in
the inclusive process based on a data set of 62
at the center-of-mass energy GeV collected with
the BESIII detector. These asymmetries can be attributed to the Collins
fragmentation function. We observe a nonzero asymmetry, which increases with
increasing pion momentum. As our energy scale is close to that of the existing
semi-inclusive deep inelastic scattering experimental data, the measured
asymmetries are important inputs for the global analysis of extracting the
quark transversity distribution inside the nucleon and are valuable to explore
the energy evolution of the spin-dependent fragmentation function.Comment: 7 pages, 5 figure
Measurement of the phase between strong and electromagnetic amplitudes of decays
Using 16 points of annihilation data collected in the vicinity of the resonance with the BESIII detector and with a total integrated luminosity of around 100 pb, we study the relative phase between the strong and electromagnetic amplitudes of decays. The relative phase between the electromagnetic decay and the continuum process ( annihilation without the resonance) is confirmed to be zero by studying the Born cross section lineshape of production. The relative phase between the strong and electromagnetic decays is then measured to be for the final state by investigating the interference pattern between the decay and the continuum processes. This is the first measurement of the relative phase between strong and electromagnetic decays into a multi-hadron final state using the lineshape of the production cross section. We also study the production lineshape of the multi-hadron final state with , which provides additional information about the phase between the electromagnetic decay amplitude and the continuum process. Additionally, the branching fractions of and are measured to be and , respectively, which are consistent with the world average values. The quoted uncertainties include both statistical and systematic uncertainties
Analyse experimentale des mecanismes de coercivite dans les aimants Nd-Fe-B frittes
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc