122892862
Search for alpha inelastic condensed state in 24Mg
The alpha inelastic scattering from 24Mg was measured to obtain the isoscalar natural-parity excitation strengths and to search for α-condensed states. Multipole decomposition analysis was performed for the measured cross sections, and the strength distributions for the ΔL = 0–3 transitions were successfully obtained. The decay particles from the excited states in 24Mg were also measured in concidence with the inelastically scattered alpha particles. Candidates were found for α-condensed states around the 16O core.
123764763
Complete set of deuteron analyzing powers for dp elastic scattering at intermediate energies
With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers (iT 11, T 20, T 21, T 22) in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne’99, and UrbanaIX three nucleon forces.
56001873
Complete Set of Deuteron Analyzing Powers for dp Elastic Scattering at Intermediate Energies and Three Nucleon Forces
With the aim of clarifying roles of the 3NFs in nuclei experimental programs with the polarized deuteron beam at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers in deuteron–proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon–nucleon forces together with the Tucson–Melbourne’99, and UrbanaIX three nucleon forces.
122292360
SAMURAI spectrometer for RI beam experiments
Abstract A large-acceptance multiparticle spectrometer SAMURAI has been constructed at the RIKEN RI Beam Factory (RIBF) for RI beam experiments. It was designed primarily for kinematically complete experiments such as the invariant-mass spectroscopy of particle-unbound states in exotic nuclei, by detecting heavy fragments and projectile-rapidity nucleons in coincidence. The system consists of a superconducting dipole magnet, beam line detectors, heavy fragment detectors, neutron detectors, and proton detectors. The SAMURAI spectrometer was commissioned in March 2012, and a rigidity resolution of about 1/1500 was obtained for RI beams up to 2.4 GeV/c.
96206265
Production cross section measurements of radioactive isotopes by BigRIPS separator at RIKEN RI Beam Factory
Abstract We have measured the production rates and production cross sections for a variety of radioactive isotopes which were produced from 124 Xe, 48 Ca, and 238 U beams at an energy of 345 MeV/nucleon using the BigRIPS separator at the RIKEN Nishina Center RI Beam Factory (RIBF). Proton-rich isotopes with atomic numbers Z  = 40–52 and neutron-rich isotopes with Z  = 5–16 were produced by projectile fragmentation of the 124 Xe and 48 Ca beam on Be targets, respectively. Neutron-rich isotopes with Z  = 20–59 were produced by in-flight fission of the 238 U beam, in which both Be and Pb were used as production targets. The measured production rates and production cross sections were compared with those of the LISE ++ calculations, and overall fairly good agreement has been obtained. Furthermore, in the measurements with the 124 Xe beam, we have discovered four new isotopes on the proton-drip line, 85,86 Ru and 81,82 Mo, and obtained the clear evidence that 103 Sb is particle unbound with an upper limit of 49 ns for the half-life. The measurements of projectile-fragment momentum distributions have been also performed with the 124 Xe beam, in which the low-momentum tails of the distributions have been measured for the first time at the energy of 345 MeV/nucleon.
95032063
SHARAQ spectrometer for high-resolution studies for RI-induced reactions
Abstract The SHARAQ spectrometer and High-Resolution Beamline, which began operation in March 2009, have been put into use for six experiments using charge exchange reactions with radioactive isotope beams. For experiments at SHARAQ, detector developments and ion optics studies continue to improve performance in high-resolution nuclear spectroscopy. We have introduced improved timing resolution with CVD diamond detectors, high count-rate beamline tracking detectors and development of multi-particle detection by cathode-readout drift chambers. Ion-optics studies for the high-resolution achromatic (HA) and dispersion-matching (DM) transport modes are also reported here. Momentum tagging in the HA mode demonstrated an improvement in spectroscopic resolution with respect to the momentum spread of the radioactive beam. For the DM transportation mode, a momentum resolution of 1 / 8100 (FWHM) was achieved by taking into account the positions and angles of the beam at the third focal plane of BigRIPS.
85464332
Effect of Regge Cut in Asymptotically Free Field Theory
now shrink as [q[ becomes The fixed branch points similar to those in Eq. (L1) have also been found in the relativistic field theories. In any known renormalizable such as r/;/, and QED, the elastic seatteri ng amplitude has a square-root cut which depends on g2 but not on the momentum in the ladder approximatior~."l Taking a i~ctitious r/;6 3 theory and solving the BS-equation with one particle exchange kernel, Lovelace4l has shown that the deep inelastic scattering amplitude behaves as
119426197
Nuclear wobbling motion and electromagnetic transitions
Abstract The nuclear wobbling motion is studied from a microscopic viewpoint. It is shown that the expressions not only of the excitation energy but also of the electromagnetic-transition rate in the microscopic RPA framework can be cast into the corresponding forms of the macroscopic rotor model. Criteria to identify the rotational band associated with the wobbling motion are given. Examples of realistic calculations are investigated and some theoretical predictions are presented.
92983154
Ground-state properties of neutron-rich Mg isotopes
We analyze recently measured total reaction cross sections for ${}^{24--38}$Mg isotopes incident on ${}^{12}$C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics (AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of ${}^{24--38}$Mg are then deduced from the measured reaction cross sections by fine tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for ${}^{24--36}$Mg, but still considerably underestimate them for ${}^{37,38}$Mg. The large matter radii suggest that ${}^{37,38}$Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number ($N$) dependence of deformation parameter is predicted by AMD. Large deformation is seen from ${}^{31}$Mg with $N=19$ to a drip-line nucleus ${}^{40}$Mg with $N=28$, indicating that both the $N=20$ and 28 magicities disappear. $N$ dependence of neutron skin thickness is also predicted by AMD.
55415432
Forward physics with the LHCf experiment: a LHC contribution to cosmic-ray physics
LHCf is a small detector installed at LHC accelerator to measure neutral par- ticle flow in the forward direction of proton - proton (p - p) and proton - nucleus (p - A) interactions. Thanks to the optimal performance that has characterized the last years' running of the LHC collider, several measurements have been taken since 2009 in differ- ent running conditions. After data taking for p - p interactions at √ s = 900 GeV, 2.76 TeV and 7 TeV and proton - Lead nucleus (p - Pb) at √ sNN = 5.02 TeV (energy of a couple of projectile and target nucleons in their center of mass reference frame), LHCf is now going to complete its physics program with the 13 TeV p - p run foreseen in 2015. The com- plete set of results will become a reference data set of forward physics for the calibration and tuning of the hadronic interaction models currently used for the simulation of the atmospheric showers induced by very high energy cosmic rays. For this reason we think that LHCf is giving an important contribution for the study of cosmic rays at the highest energies. In this paper the experiment, the published results and the current status are reviewed.
14513100
MICROSCOPIC DESCRIPTION OF NUCLEAR WOBBLING MOTION ROTATION OF TRIAXIALLY DEFORMED NUCLEI
The nuclear wobbling motion in the Lu region is studied by the microscopic cranked mean-field plus RPA method. The Woods-Saxon potential is used as a mean-field with a new parameterization which gives reliable description of rapidly rotating nuclei. The prescription of symmetry-preserving residual interaction makes the calculation of the RPA step parameter-free, and we find the wobbling-like RPA solution if the triaxial deformation of the mean-field is suitably chosen. It is shown that the calculated out-of-band B(E2) of the wobbling-like solution depends on the triaxial deformation in the same way as in the macroscopic rotor model, and can be used to probe the triaxiality of the nuclear mean-field.