We analyze recently measured total reaction cross sections for [24][25][26][27][28][29][30][31][32][33][34][35][36][37][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][25][26][27][28][29][30][31][32][33][34][35][36][37][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][25][26][27][28][29][30][31][32][33][34][35][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.

[1] Temporal and latitudinal variations of vertical profiles of N 2 O isotopomers were observed in the stratosphere over Japan (39°N, 142°E), Sweden (68°N, 20°E) O were nearly constant in the lower stratosphere (less than $22 km) but increased at higher altitudes ($22-35 km) while showing seasonal and latitudinal differences. Enrichment factors during the photolysis and photo-oxidation of N 2 O were also obtained in laboratory experiments and compared with those observed. We found that in the higher-altitude region (1) fractionation of the isotopomers is mainly determined by photolysis, but is also affected by physical processes, (2) subsidence of air masses in the winter polar vortex induces the intrusion of an upper stratospheric air mass depleted in N 2 O, and (3) decay of the vortex in the local spring leads to rapid horizontal advection of midlatitude air masses. At lower altitudes, isotopomer ratios are determined by photolysis, photo-oxidation, and the mixing of air masses within the stratosphere or between the stratosphere and the troposphere. Secular trend of isotopomer profiles was not detectable over Japan during 11 years. Assuming that the lower stratospheric air over midlatitudes is exchanged with the troposphere, isotopomer ratios of the N 2 O ''back-flux'' from the stratosphere were estimated. These values can be used in the isotopomeric mass balance model to constrain the global N 2 O budget.

A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238 U beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center. Fission fragments were analyzed and identified by using the superconducting in-flight separator BigRIPS. We observed 45 new neutron-rich isotopes: Since the pioneering production of radioactive isotope (RI) beams in the 1980s, 1) studies of exotic nuclei far from stability have been attracting much attention. Neutron-rich exotic nuclei are of particular interest, because new phenomena such as neutron halos, neutron skins, and modifications of shell structure have been discovered.2-5) Furthermore these neutron-rich nuclei are important in relation to astrophysical interests, 6) because many of them play a role in the astrophysical r-process. 7) To make further advances in nuclear science and nuclear astrophysics, it is essential to expand the region of accessible exotic nuclei towards the neutron dripline. In-flight fission of a uranium beam is known to be an excellent mechanism for this purpose, having large production cross sections for neutron-rich exotic nuclei. became operational, in which the superconducting in-flight separator BigRIPS 10,11) has been used for the production of RI beams. The BigRIPS separator is designed as a two-stage separator with large acceptance, so that excellent features of in-flight fission can be exploited. In May 2007, right after the commissioning of the BigRIPS separator, we performed an experiment to search for new isotopes using in-flight fission of a 345 MeV/nucleon 238 U beam, aiming to expand the LETTERS Ã

Using light to manipulate materials into desired states is one of the goals in condensed matter physics, since light control can provide ultrafast and environmentally friendly photonics devices. However, it is generally difficult to realise a photo-induced phase which is not merely a higher entropy phase corresponding to a high-temperature phase at equilibrium. Here, we report realisation of photo-induced insulator-to-metal transitions in Ta2Ni(Se1−xSx)5 including the excitonic insulator phase using time- and angle-resolved photoemission spectroscopy. From the dynamic properties of the system, we determine that screening of excitonic correlations plays a key role in the timescale of the transition to the metallic phase, which supports the existence of an excitonic insulator phase at equilibrium. The non-equilibrium metallic state observed unexpectedly in the direct-gap excitonic insulator opens up a new avenue to optical band engineering in electron–hole coupled systems.

The cross section for the *L'\(a,n) n B reaction, which is crucial to predictions of primordial nucleosynthesis in inhomogeneous models, has been measured using the radioactive-beam facility of the Institute for Physical and Chemical Research (RIKEN). The reaction cross section to all allowed n B states was found to be larger than that to just the M B ground state by about a factor of 5. (7) PACS numbers: 25.55.Hp, 95.30.Cq, 98.80.Ft The standard (homogeneous) model (SM) [1] of primordial nucleosynthesis has been known for some time to give reasonable predictions of the abundances of the nuclides up to 4 He (although recent work [2] on 4 He has raised questions about the agreement between theory and observation), and arguably valid predictions [3] for 7 Li as well. However, consideration of density inhomogeneities, possibly resulting from the quark-hadron phase transition thought to have occurred 10 ~5 s after the big bang, has led to a set of alternate models, the inhomogeneous models (IMs) [4,5]. In the IMs, the abundances predicted for light nuclides are similar to those predicted by the SM, but those for 7 Li, 9 Be, M B, and heavier nuclides are considerably higher for most of the IM parameter space. Unfortunately, the abundance of 7 Li, which is fairly easily measured by astronomers, is difficult to interpret [6-9]. Recent studies [10,11] of 9 Be, however, have pushed its abundance in metal poor stars to potentially interesting levels [12]. But M B and heavier nuclides may ultimately provide important tests of primordial nucleosynthesis; indeed the relative insensitivity [13] of the predicted M B abundance to the IM parameters may make it an ideal test of those models. Furthermore, a recent observation [14] has shown n B can be detected in metal poor stars, using the Hubble Space Telescope, at levels relevant to predictions of primordial nucleosynthesis [5]. A critical reaction in predicting abundances of n B and heavier nuclides in the IMs is 8 Li(a,Az) n B, as n B is the nuclide through which most heavier nuclides must pass, and that reaction apparently regulates the dominant pathway by which M B is made [5]. Observation of this reaction, however, is complicated by the 840.3-ms halflife [15] of 8 Li. A recent measurement [16] of the inverse reaction n B(«,a) 8 Li gives the ground-stateground-state cross section for 8 Li(a,Ai) M B. However, several M B excited states can be populated in 8 Li(a,A*) n B, so inference of the cross section of interest from measurement of the inverse reaction may underesti-