160 research outputs found
Experimental investigation of the few-nucleon dynamics in deuteron-deuteron collision at 160 MeV
An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid deuterium target, was carried out using BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-section for the deuteron break-up reaction. The elastic scattering data were also collected alongside for the purpose of cross-section normalization. We present here a sample of the un-normalised cross-section for the three-body final state reaction
Three- and four-nucleon dynamics at intermediate energies
An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid hydrogen and liquid deuterium targets, was carried out using BINA detector at KVI in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross sections of break-up channels in dp and dd collisions. The elastic scattering data were also collected alongside for the purpose of cross-section normalization. A brief description of the experiment and the data analysis as well as some preliminary results are presented
Experimental investigation of few-nucleon dynamics at medium energies
An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid hydrogen and liquid deuterium targets, was carried out using BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-section for the deuteron break-up reaction. The elastic scattering data were also collected alongside. We present here the methods applied in analysis of data collected in the backward part of the detector
Vector and tensor analyzing powers in deuteron-proton breakup at 130 MeV
High-precision data for vector and tensor analyzing powers for the 1H(d,pp)n reaction at a 130-MeV deuteron beam energy have been measured over a large part of the phase space. Theoretical predictions based on various approaches to describe the three nucleon (3N) system reproduce very well the vector analyzing power data and no three-nucleon force effect is observed for these observables. Tensor analyzing powers are also very well reproduced by calculations in almost the whole studied region, but locally certain discrepancies are observed. For Axy such discrepancies usually appear, or are enhanced, when model 3N forces, TM99 or Urbana, are included. Problems of all theoretical approaches with describing Axx and Ayy are limited to very small kinematical regions, usually characterized by the lowest energy of the relative motion of the two protons
Spin tune mapping as a novel tool to probe the spin dynamics in storage rings
Precision experiments, such as the search for electric dipole moments of
charged particles using storage rings, demand for an understanding of the spin
dynamics with unprecedented accuracy. The ultimate aim is to measure the
electric dipole moments with a sensitivity up to 15 orders in magnitude better
than the magnetic dipole moment of the stored particles. This formidable task
requires an understanding of the background to the signal of the electric
dipole from rotations of the spins in the spurious magnetic fields of a storage
ring. One of the observables, especially sensitive to the imperfection magnetic
fields in the ring is the angular orientation of stable spin axis. Up to now,
the stable spin axis has never been determined experimentally, and in addition,
the JEDI collaboration for the first time succeeded to quantify the background
signals that stem from false rotations of the magnetic dipole moments in the
horizontal and longitudinal imperfection magnetic fields of the storage ring.
To this end, we developed a new method based on the spin tune response of a
machine to artificially applied longitudinal magnetic fields. This novel
technique, called \textit{spin tune mapping}, emerges as a very powerful tool
to probe the spin dynamics in storage rings. The technique was experimentally
tested in 2014 at the cooler synchrotron COSY, and for the first time, the
angular orientation of the stable spin axis at two different locations in the
ring has been determined to an unprecedented accuracy of better than
rad.Comment: 32 pages, 15 figures, 7 table
Phase Measurement for Driven Spin Oscillations in a Storage Ring
This paper reports the first simultaneous measurement of the horizontal and
vertical components of the polarization vector in a storage ring under the
influence of a radio frequency (rf) solenoid. The experiments were performed at
the Cooler Synchrotron COSY in J\"ulich using a vector polarized, bunched
deuteron beam. Using the new spin feedback system, we
set the initial phase difference between the solenoid field and the precession
of the polarization vector to a predefined value. The feedback system was then
switched off, allowing the phase difference to change over time, and the
solenoid was switched on to rotate the polarization vector. We observed an
oscillation of the vertical polarization component and the phase difference.
The oscillations can be described using an analytical model. The results of
this experiment also apply to other rf devices with horizontal magnetic fields,
such as Wien filters. The precise manipulation of particle spins in storage
rings is a prerequisite for measuring the electric dipole moment (EDM) of
charged particles
Determination of Deuteron Beam Polarizations at COSY
The vector and tensor polarizations of a deuteron beam have been measured
using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton
scattering at 270 MeV. After acceleration to 1170 MeV inside the COSY ring, the
polarizations of the deuterons were checked by studying a variety of nuclear
reactions using a cluster target at the ANKE magnet spectrometer placed at an
internal target position of the storage ring. All these measurements were
consistent with the absence of depolarization during acceleration and provide a
number of secondary standards that can be used in subsequent experiments at the
facility.Comment: 12 pages, 13 figure
Investigation of three nucleon force effects in deuteron-proton breakup reaction
Experimental study of the deuteron-proton breakup process was perfomed in KVI Groningen. In this paper current status of the collected data analysis is presented, including preliminary results of the cross section for the sample kinematical configuration
Charge Symmetry Breaking in dd->4He{\pi}0 with WASA-at-COSY
Charge symmetry breaking (CSB) observables are a suitable experimental tool
to examine effects induced by quark masses on the nuclear level. Previous high
precision data from TRIUMF and IUCF are currently used to develop a consistent
description of CSB within the framework of chiral perturbation theory. In this
work the experimental studies on the reaction dd->4He{\pi}0 have been extended
towards higher excess energies in order to provide information on the
contribution of p-waves in the final state. For this, an exclusive measurement
has been carried out at a beam momentum of p=1.2 GeV/c using the WASA-at-COSY
facility. The total cross section amounts to sigma(tot) = (118 +- 18(stat) +-
13(sys) +- 8(ext)) pb and first data on the differential cross section are
consistent with s-wave pion production.Comment: 14 pages, 5 figure
ABC Effect and Resonance Structure in the Double-Pionic Fusion to He
Exclusive and kinematically complete measurements of the double pionic fusion
to He have been performed in the energy region of the so-called ABC effect,
which denotes a pronounced low-mass enhancement in the -invariant mass
spectrum. The experiments were carried out with the WASA detector setup at
COSY. Similar to the observations in the basic reaction
and in the He reaction, the data reveal a correlation
between the ABC effect and a resonance-like energy dependence in the total
cross section. Differential cross sections are well described by the hypothesis
of resonance formation during the reaction process in addition to the
conventional -channel mechanism. The deduced resonance
width can be understood from collision broadening due to Fermi motion of the
nucleons in initial and final nuclei
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