Realtime calibration of the A4 electromagnetic lead fluoride calorimeter

Sufficient energy resolution is the key issue for the calorimetry in particle and nuclear physics. The calorimeter of the A4 parity violation experiment at MAMI is a segmented calorimeter where the energy of an event is determined by summing the signals of neighbouring channels. In this case the precise matching of the individual modules is crucial to obtain a good energy resolution. We have developped a calibration procedure for our total absorbing electromagnetic calorimeter which consists of 1022 lead fluoride (PbF_2) crystals. This procedure reconstructs the the single-module contributions to the events by solving a linear system of equations, involving the inversion of a 1022 x 1022-matrix. The system has shown its functionality at beam energies between 300 and 1500 MeV and represents a new and fast method to keep the calorimeter permanently in a well-calibrated state

Measurement of the parity violating asymmetry in the quasielastic electron-deuteron scattering and improved determination of the magnetic strange form factor and the isovector anapole radiative correction

A new measurement of the parity-violating asymmetry in the electron-deuteron quasielastic scattering for backward angles at ⟨Q[superscript 2]⟩=0.224 (GeV/c)[superscript 2], obtained in the A4 experiment at the Mainz Microtron accelerator (MAMI) facility, is presented. The measured asymmetry is A[subscript PV][superscript d]=(-20.11±0.87[subscript stat]±1.03[subscript sys])×10[superscript -6]. A combination of these data with the proton measurements of the parity-violating asymmetry in the A4 experiment yields a value for the effective isovector axial-vector form factor of G[subscript A][superscript e,(T=1)]=-0.19±0.43 and R[subscript A][superscript e(T=1),anap] =-0.41±0.35 for the anapole radiative correction. When combined with a reanalysis of measurements obtained in the G0 experiment at the Thomas Jefferson National Accelerator Facility, the uncertainties are further reduced to G[subscript M][superscript s]=0.17±0.11 for the magnetic strange form factors, and R[subscript A][superscript (T=1),anap]=-0.54±0.26.Deutsche Forschungsgemeinschaf

New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets

New measurements of the beam normal single spin asymmetry in the electron elastic and quasielastic scattering on the proton and deuteron, respectively, at large backward angles and at Q2=0.22 (GeV/c)2 and Q2=0.35 (GeV/c)2 are reported. The experimentally observed asymmetries are compared with the theoretical calculation of Pasquini and Vanderhaeghen [Phys. Rev. C 70, 045206 (2004).PRVCAN0556-281310.1103/PhysRevC.70.045206]. The agreement of the measurements with the theoretical calculations shows a dominance of the inelastic intermediate excited states of the nucleon, πN and the Δ resonance. The measurements explore a new, important parameter region of the exchanged virtual photon virtualities

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel $\bar p p \to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, $\textit{i.e.}$ $\bar p p \to \pi^+ \pi^-$, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

Traceability of human sperm samples by direct tagging with polysilicon microbarcodes

© 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved. The increasing number of patients undergoing assisted reproductive technology (ART) treatments and of cycles performed in fertility centres has led to some traceability errors. Although the incidence of mismatching errors is extremely low, any error is unacceptable, therefore different strategies have been developed to further minimize these errors, such as manual double-witnessing or electronic witnessing systems. More recently, our group developed a direct tagging method consisting of attaching microbarcodes directly to the zona pellucida of human oocytes/embryos. Here, this method is taken a step further by using these microbarcodes to tag human semen samples, demonstrating that the barcodes are not toxic and do not interfere in the selection of motile spermatozoa nor in the cryopreservation of the sperm samples. In addition, when this tagging system was applied to an animal model (rabbit), pregnancy rate and kitten viability were not affected.Peer Reviewe

New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets

International audienceNew measurements of the beam normal single spin asymmetry in the electron elastic and quasielastic scattering on the proton and deuteron, respectively, at large backward angles and at ⟨Q2⟩=0.22  (GeV/c)2 and ⟨Q2⟩=0.35  ( GeV/c)2 are reported. The experimentally observed asymmetries are compared with the theoretical calculation of Pasquini and Vanderhaeghen [Phys. Rev. C 70, 045206 (2004).PRVCAN0556-281310.1103/PhysRevC.70.045206]. The agreement of the measurements with the theoretical calculations shows a dominance of the inelastic intermediate excited states of the nucleon, πN and the Δ resonance. The measurements explore a new, important parameter region of the exchanged virtual photon virtualities

Measurement of the parity violating asymmetry in the quasielastic electron-deuteron scattering and improved determination of the magnetic strange form factor and the isovector anapole radiative correction

International audienceA new measurement of the parity-violating asymmetry in the electron-deuteron quasielastic scattering for backward angles at ⟨Q2⟩=0.224  (GeV/c)2, obtained in the A4 experiment at the Mainz Microtron accelerator (MAMI) facility, is presented. The measured asymmetry is APVd=(-20.11±0.87stat±1.03sys)×10-6. A combination of these data with the proton measurements of the parity-violating asymmetry in the A4 experiment yields a value for the effective isovector axial-vector form factor of GAe,(T=1)=-0.19±0.43 and RA(T=1),anap=-0.41±0.35 for the anapole radiative correction. When combined with a reanalysis of measurements obtained in the G0 experiment at the Thomas Jefferson National Accelerator Facility, the uncertainties are further reduced to GMs=0.17±0.11 for the magnetic strange form factors, and RA(T=1),anap=-0.54±0.26