119572715
Decoupling of valence neutrons from the core in 16C
Abstract The neutron and proton excitations in 16 C nucleus have been investigated by use of the Coulomb-nuclear interference method applied to the 208 Pb+ 16 C inelastic scattering. Angular distribution of the 16 C nuclei in the inelastic channel populating the first 2 + state has been measured. The neutron and proton transition matrix elements, M n and M p , have been determined from the “Coulomb” and “matter” deformation-length parameters obtained by distorted wave calculations. The M p or its corresponding B (E2;2 + 1 →0 + ) value was found to be extremely small: 0.28±0.06 Weisskopf units consistent with a recent lifetime measurement. Furthermore, the extracted M n / M p ratio has an unexpectedly large value of 7.6±1.7. These results suggest that the 2 + 1 state in 16 C is a nearly pure valence neutron excitation.
121300048
DECAY PATTERN OF PYGMY STATES OBSERVED IN NEUTRON-RICH 26Ne
Coulomb excitation of the exotic neutron-rich nucleus 26Ne on a 208Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. The radioactive beam was produced by fragmentation of a 95 A.MeVAr beam delivered by the RIKEN Accelerator Research Facility. The set-up included a NaI(Tl) gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the 25Ne+n channel, we observe by multipole decomposition a sizable amount of E1 strength between 6 and 10 MeV excitation energy. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured.
124527547
Measurement of the spin and magnetic moment of ²³Al
Author(s) Ozawa, A.; Matsuta, K.; Nagatomo, T.; Mihara, M.; Yamada, K.; Yamaguchi, T.; Momota, S.; Izumikawa, T.; Sumikama, T.; Nakashima, Y.; Fujiwara, H.; Kumashiro, S.; Matsumiya, R.; Ota, M.; Shinojima, D.; Tanaka, H.; Yasuno, T.; Nakajima, S.; Suzuki, T.; Yoshida, K.; Muranaka, K.; Maemura, T.; Chiba, A.; Utsuno, Y.; Fukuda, M.; Tanaka, K.; Tanihata, I.; Nojiri, Y.; Minamisono, T.; Alonso, J.R.; Krebs, G.F.; Symons, T.J.M.
54645664
Study of halo structure of C from reaction cross section measurement
Abstract The reaction cross sections for 12,16 C have been measured at the energy of 83 A MeV by a new experimental method. The larger enhancement of the 16 C reaction cross section at the low energy has been used to study the density distribution of  16 C. The finite-range Glauber-model calculations for different density distributions have been compared with the experimental data. The analysis suggests that 16 C mainly has a 14 C(core) + 2n structure and shows a strong contribution of (2s1/2)2 for valence neutrons. A large extension of the neutron density distribution to a distance far from the center of the nucleus suggests the formation of neutron halo in the 16 C nucleus.
120128880
Negative pion production in subthreshold heavy ion collisions
Abstract Inclusive π− spectra have been measured for 14N+C collisions at 41A, 67A, 80A and 135A MeV, the lowest energies measured for the charged pion. The cross sections fall exponentially with Tπ and the exponential slope factors at 90° in the nucleon-nucleon center of mass frame are determined. Energy distributions below a beam energy of 100A MeV are less steep than expected from the monotonic decrease of the slope factor down to 100A MeV. The production mechanism of energetic pions far below threshold is discussed for several models.
120765038
Attempts in detection of neutrons on So-called cold nuclear fusion
Neutron emissions from electrolysis of D 2 O with palladium and palladium-titanium electrodes as well as from pressurized D 2 gas with titanium alloys have been measured. The neutron detector system was so designed to have very low background condition. Neutron-γ separation technique using liquid scintillator was applied to obtain essentially no γ ray background condition for neutron counting. Special care was taken to stabilize the detection system using event-by-event data recording. No significant signal of neutron emission was observed. Upper limits of emission probability of neutron have been determined to be 6×10 -3 s -1 , 1×10 -2 s -1 , and 2.3×10 -2 s -1 for Pd electrode, Pd-Ti electrode, and pressurized gas systems. These values are orders of magnitude lower than that presented by Jones paper (0.4 s -1 ).
14118678
One-loop flatness of membrane fuzzy sphere interaction in plane-wave matrix model
Abstract In the plane-wave matrix model, the background configuration of two membrane fuzzy spheres, one of which rotates around the other one in the SO (6) symmetric space, is allowed as a classical solution. We study the one-loop quantum corrections to this background in the path integral formulation. Firstly, we show that each fuzzy sphere is stable under the quantum correction. Secondly, the effective potential describing the interaction between fuzzy spheres is obtained as a function of r , which is the distance between two fuzzy spheres. It is shown that the effective potential is flat and hence the fuzzy spheres do not feel any force. The possibility on the existence of flat directions is discussed.
18669890
Asymptotic symmetries of Schrödinger spacetimes
We discuss the asymptotic symmetry algebra of the Schrodinger -invariant metrics in d+3 dimensions and its realization on finite temperature solutions of gravity coupled to matter fields. These solutions have been proposed as gravity backgrounds dual to non-relativistic CFTs with critical exponent z in d space dimensions. It is known that the Schrodinger algebra possesses an infinite-dimensional extension, the Schrodinger-Virasoro algebra. However, we show that the asymptotic symmetry algebra of Schrodinger spacetimes is only isomorphic to the exact symmetry group of the background. It is possible to construct from first principles finite and integrable charges that infinite-dimensionally extend the Schrodinger algebra but these charges are not correctly represented via a Dirac bracket. We briefly comment on the extension of our analysis to spacetimes with Lifshitz symmetry.
119104739
Noncommutative M-branes from Covariant Open Supermembranes
We discuss an open supermembrane in the presence of a constant three-form. The boundary conditions to ensure the �-invariance of the action lead to possible Dirichlet branes. It is shown that a noncommutative (NC) M5-brane is possible as a boundary and the self-duality condition that the flux on the world-volume satisfies is derived from the requirement of the �-symmetry. We also find that the open supermembrane can attach to each of infinitely many M2-branes on an M5-brane, namely a strong flux limit of the NC M5-brane. PACS numbers: 11.25.Yb, 11.25.Uv, 11.25.-w, 11.25.Wx Open supermembranes [1] are attractive objects. Supermembranes [2] are considered as fundamental objects of M-theory [3], which is believed to be the unified theory of superstrings, and open supermembranes are especially interesting because of connection to some realistic phenomenological models via the Horava-Witten scenario [4]. It is well-known that an open supermembrane in flat spacetime can attach on Dirichlet p-branes with p = 1,5 and 9 [5, 6]. The p = 5 case corresponds to M5-brane and the case with p = 9 is nothing but the end of the world nine-brane discussed in the Horava-Witten theory [4]. As a recent progress, open M5-branes have also been discussed in [7]. It is interesting to consider a generalization of studies of open supermembranes by including constant threeform gauge field (gauge field condensate). In this direction an approach based on the light-cone gauge, with which supermembrane theory is well studied, is not desirable because the light-cone coordinates should inevitably be Neumann directions and furthermore one cannot consider arbitrary electric fluxes. Thus a covariant approach is more appropriate for our purpose [8]. In this letter we basically follow the covariant procedure utilized in [5]. This type of procedure was used to study D-branes of Green-Schwarz (GS) string theories in [9]. We discuss NC M5-branes from the requirement of the κ-symmetry of a covariant GS action of an open supermembrane with constant fluxes. In case of open supermembrane, the surface terms appear under the κ-variation of the action and hence they should be deleted by imposing some appropriate boundary conditions. The usual NC M5-branes are surely included among the conditions, for which the self-duality condition of the flux on the worldvolume is also obtained from the condition that the projection operator should satisfy. In addition, p = 2 case is
123690671
Non-local representation of (2+1)-dimensional quantum gravity with spinor field
Non-local representation of(2+1)-dimensional quantum gravity coupled with the spinor field is considered. We first introduce non-local variables and obtain non-local quantities that are equivalent to the local constraints in some limit. The quantization of these non-local variables is executed in a non-local representation that is similar to the loop representation of pure gravity. The contribution of spinor fields in the state functionals depends not only on the space of loops but also on the space of lines. A state functional which is the solution of all constraint equations is also obtained.
15410068
Discrete light-cone quantization in pp-wave background
We discuss the discrete light-cone quantization (DLCQ) of a scalar field theory on the maximally supersymmetric pp-wave background in ten dimensions. It has been shown that the DLCQ can be carried out in the same way as in the two-dimensional Minkowski spacetime. Then, the vacuum energy is computed by evaluating the vacuum expectation value of the light-cone Hamiltonian. The results are consistent with the effective potential obtained in our previous work [hep-th/0402028].