Search results for "Low energy"

Dispersion relations in real and virtual Compton scattering

2002

A unified presentation is given on the use of dispersion relations in the real and virtual Compton scattering processes off the nucleon. The way in which dispersion relations for Compton scattering amplitudes establish connections between low energy nucleon structure quantities, such as polarizabilities or anomalous magnetic moments, and the nucleon excitation spectrum is reviewed. We discuss various sum rules for forward real and virtual Compton scattering, such as the Gerasimov-Drell-Hearn sum rule and its generalizations, the Burkhardt-Cottingham sum rule, as well as sum rules for forward nucleon polarizabilities, and review their experimental status. Subsequently, we address the general…

Test of Low-Energy Theorems forH1(γ→,π0)H1in the Threshold Region

2001

The photon asymmetry in the reaction H-1(, pi (0))H-1 close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized photons from the tagged-photon facility at the Mainz Microtron MAMI. The total and differential cross sections were also measured simultaneously with the photon asymmetry. This allowed determination of the S-wave and all three P-wave amplitudes. The values obtained at threshold are E0+ = [-1.33 +/- 0.08(stat) +/- 0.03(syst)] x 10(-3)/m(pi+), P-1 = [9.47 +/- 0.08(stat) +/- 0.29(syst)] x 10(-3)q /m(pi+)(2) P-2 [-9.46 +/- 0.1(stat) +/- 0.29(syst)] x 10(-3)q/m(pi+)(2), and P-3 = [11.48 +/- 0.06(stat) +/- 0.35(syst)] x 10(-3)q/m(…

First Measurements with the DTAS Detector

2016

The DTAS detector will be an important instrument in the DESPEC experiment at FAIR for \(\beta \)-decay studies of exotic nuclei far from stability. The first measurements with this new detector have been performed with low energy radioactive beams at the upgraded IGISOL IV facility. The characterization of the detector was done by comparison of measurements with Monte Carlo (MC) simulations , and the first analysis of the cases of interest are in progress.

Low Energy Protons at RADEF - Application to Advanced eSRAMs

2014

A low energy proton facility has been developed at RADEF, Jyvskyl, Finland. The proton energy selection, calibration and dosimetry are described. The first experiment with external users was performed using two memory test vehicles fabricated with 28 nm technology. Examples of single event upset measurements in the test vehicles embedded SRAMs (eSRAMs) as a function of proton energy are provided.

Low-energy constants from resonance chiral theory

2008

I discuss the recent attempts to build an effective chiral Lagrangian incorporating massive resonance states. A useful approximation scheme to organize the resonance Lagrangian is provided by the large-Nc limit of QCD. Integrating out the resonance fields, one recovers the usual chiral perturbation theory Lagrangian with explicit values for the low-energy constants, parameterized in terms of resonance masses and couplings. The resonance chiral theory generates Green functions that interpolate between QCD and chiral perturbation theory. Analyzing these Green functions, both for large and small momenta, one gets QCD constraints on the resonance couplings and, therefore, information on the low…

Physics at MAMI C

2005

The physics motivation for the energy increase of the Mainz Microtron from 885 to 1500 MeV (MAMI C) is presented. It is argued that the low energy regime in hadron physics where the perturbative approach to QCD is not applicable is the most relevant to further understand this peculiar theory. However, the investigation of the most significant observables needs excellent experimental precision and an intensive interaction with theory. As examples the recent measurement of the form factor of the neutron and the pion polarisability are presented. They show that the mentioned conditions are given at MAMI and will be extended by the energy increase.

Finite Energy Sum Rules with Legendre Polynomial Kernels

2016

Abstract In this note we report about a method to deal with finite energy sum rules. With a reasonable knowledge of the main resonances of the spectrum, the method guarantees that we can find a nice duality matching between the low energy hadronic data and asymptotic QCD at high energies.

Microscopic Study of Pionic Atoms and Methods of Production

1992

We have constructed a theoretical optical potential for pionic atoms and low energy pions based on the first and second order terms of a many body expansion on the number of ph excitations. The new density dependence of the potential produces notoriously improved results in the problem of the anomalies. On the other hand we have separated the different contributions to the imaginary part of the potential and relate them to the different reaction channels, quasielastic and absorption. The agreement with the data for different channels, energies and nuclei is rather good with some isolated discrepancies. With this potential we have also investigated the deeply bound pionic states in heavy nuc…

Low Energy Behaviour of the Phase Shifts for Velocity-Dependent Potentials

1973

IceCube Sensitivity for Low-Energy Neutrinos from Nearby Supernovae ( Corrigendum )

2014

Keywords: neutrinos ; supernovae: general ; instrumentation: detectors ; errata ; addenda Reference EPFL-ARTICLE-198916doi:10.1051/0004-6361/201117810eView record in Web of Science Record created on 2014-05-19, modified on 2017-05-12