Search results for "Polar"
showing 10 items of 3817 documents
Positive Muons as Local Probes in Paramagnetic Rare Earth Systems
1982
In recent years a new research method has been developed in solid state physics which is based on the asymmetry of muon decay1. A positive muon at rest decays after a mean lifetime of 2.2 μsec into a positron and two neutrinos, the positron being emitted preferentially in the direction of the muon spin. Hence if spin polarized muons are implanted in a solid, the time evolution of the muon spin polarization can be determined by a measurement of the angular distribution of the positrons. In an external magnetic field transverse to the initial spin direction of the muon one can study the muon spin precession frequency, which is determined by the actual field at the muon, and τ2-relaxation effe…
Systematic investigation of the drip-line nuclei 11Li and 14Be and their unbound subsystems 10Li and 13Be
2007
Fragmentation reactions in a carbon target with beams of 11Li and 14Be at relativistic energies have been studied in a kinematically complete experiment at the ALADIN-LAND setup at GSI. Excited states in 11Li and 14Be were obtained from the data in the inelastic channel. The measured cross sections with the core nucleus in the final state show that in the 14Be case core polarization plays an important role. In the one-neutron knockout channels the measured angular correlations between fragment and neutron are asymmetric, which demonstrates the presence of states with different parities in the 11Li and 14Be ground states. For 10Li a low-lying virtual s-state, a p-state and evidence for a d-s…
Observation and polarization measurement ofB0→a1(1260)+a1(1260)−decay
2009
We present measurements of the branching fraction B and longitudinal polarization fraction fL for B0→a1(1260)+a1(1260)- decays, with a1(1260)±→π-π+π±. The data sample, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represents 465×106 produced BB pairs. We measure B(B0→a1(1260)+a1(1260)-)×[B(a1(1260)+→π-π+π+)]2= (11.8±2.6±1.6)×10-6 and fL=0.31±0.22±0.10, where the first uncertainty is statistical and the second systematic. The decay mode is measured with a significance of 5.0 standard deviations including systematic uncertainties.
Lepton conservation and time reversal in β-decay
1959
It was investigated which conclusions can be inferred from β-decay experiments taking into account experimental errors but without making theoretical assumptions.
Recent results from experiments at MAMI
2012
Abstract The Mainz Microtron MAMI is an ideal tool for studying the structure of strongly interacting systems with an electromagnetic probe. With the new HDSM accelerator stage of MAMI C, a continuous-wave electron beam with an energy of up to 1604 MeV and excellent beam quality is available for precision experiments. In addition, polarisation degrees of freedom can be exploited with polarised beams and either polarised targets or recoil polarimetry. This paper presents selected results of the A1, A2, and A4 collaborations.
Leptoproduction of neutrino pairs in the nuclear coulomb field
1985
20 páginas, 6 figuras, 2 tablas.-- PACS. 13.60. - Photon and charged-lepton interactions with hadrons.
Relations between polarization observables and complete sets for deuteron photodisintegration
1990
The polarization observables for deuteron photodisintegration are given as Hermitean forms of theT-matrix elementsti. By inversion we are able to express a given productti*tj in terms of polarization observables. This allows (i) to derive linear relations between observables for unpolarized, circularly and linearly polarized photons, (ii) to construct explicitly complete sets of polarization observables, and (iii) to derive quadratic relations between observables.
Physics at MAMI
2008
The Mainz Microtron MAMI has delivered a high quality electron beam with maximum energy of 880MeV for many years. Recently the MAMI C stage with its maximum energy of 1.5GeV was put into operation successfully and is delivering beam routinely now. The A1 collaboration is doing electron scattering experiments with a “Three Spectrometer Setup”. A first experiment using the MAMI C beam to measure the “Recoil polarisation and beam-recoil double polarisation of eta electroproduction on the proton in the region of the S11(1535) resonance” has been finished. A new, very compact magnetic spectrometer (KaoS) suitable especially for the detection of kaons is being installed now. The A2 collaboration …
Polarization Effects in Electromagnetic Deuteron Break-Up
1992
Polarization observables of deuteron photo- and electrodisintegration with polarized photons and electrons, respectively, and oriented deuterons are investigated with respect to their sensitivity to subnuclear degrees of freedom and relativistic effects, to the different electric and magnetic multipole contributions, to various realistic potential models and — in electrodisintegration — to e.m. form factors.