120768754
Nonlinear dynamics with sextupoles in low-emittance light source storage rings
Abstract An analysis is made of the nonlinear particle motions arising from sextupoles in low-emittance light source rings. By employing the single-resonance approximation to the Hamiltonian expanded into harmonics, boundaries of the stable motion brought about by 1st- and 3rd-order resonances are calculated analytically. These are used together with the second-order tune shifts with amplitude as guidelines of the analysis and of the optimization of sextupoles to improve the dynamic aperture. The application is made to two typical lattices of the light source rings, the Chasman-Green and the triple-bend achromat lattice, to pursue the lattice dependence of the nonlinear characteristics. Apart from the cases where the stability is determined by the lowest-order resonances, studies using particle tracking indicate that the motion is very often driven by higher-order resonances for which further considerations are required. Two approaches are discussed in this context. One is to interpret the phenomena as a combined effect of the lowest-order resonances, which is verified numerically by a fictitious tracking. Another is the perturbative method. The theory developed by Poincare and von Zeipel is used to analyze the horizontal dynamics, which is worked up to 4th order in amplitude. Examples that satisfactorily reproduce the phase-space structure are shown, although it is also found that perturbations of many of the sextupoles required for these low-emittance rings are even higher than 4th order.
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 ).
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.
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.
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.
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.
12860977
Supersymmetric Extensions of Non-Relativistic Scaling Algebras
An exciting subject in string theory is to consider some applications of the AdS/CFT correspondence to realistic systems like condensed matter systems. Since most of such systems are non-relativistic, an anisotropic scaling symmetry with the general value of dynamical critical exponent z plays an important role in constructing the gravity duals for non-relativistic field theories. Supersymmetric extensions of symmetry algebras including the anisotropic scaling are very helpful to consider holographic relations accurately. We give a short summary on the classification of superalgebras with the anisotropic scaling as subalgebras of the following Lie superalgebras, psu(2,2|4), osp(8|4) and osp (8*|4), which appear in the study of AdS/CFT in type IIB string and M theories. It contains supersymmetric extensions of Schrodinger algebra and Lifshitz algebra.
119748406
Constraints on the electroweak chiral Lagrangian from the precision data
Abstract In the framework of the effective field theory method, we use the experimental data and the perturbative unitarity bounds to determine the values and uncertainty of all the 11 chiral coefficients ( α i , i = 0 , … , 10 ) of the standard electroweak chiral Lagrangian. Up to linear terms in α i , we provide the one-loop renormalization group equations of all the chiral coefficients, which are calculated in the Feynman–'t Hooft gauge using the modified minimal subtraction scheme. With the improved renormalization group equations to sum over the logarithmic corrections, we analyze the current experimental uncertainty of oblique correction parameters, S ( Λ ) and T ( Λ ) . We find that, due to the large uncertainty in the triple gauge-boson coupling measurements, the parameter space of positive S ( Λ ) for Λ > 1  TeV is still allowed by the current experimental data. T ( Λ ) tends to increase with Λ even in the presence of the operators that contribute to the triple and quartic gauge-boson couplings.
18262061
Giant graviton and quantum stability in the matrix model on app-wave background
We study classical solutions in Berenstein-Maldacena-Nastase (BMN) matrix model. A supersymmetric (1/2 BPS) fuzzy sphere is one of the classical solutions and corresponds to a giant graviton. We also consider other classical solutions, such as non-supersymmetric fuzzy sphere and harmonic oscillating gravitons. Some properties of oscillating gravitons are discussed. In particular, oscillating gravitons turn into usual supergravitons in the limit mu -> 0. Moreover, we calculate the one-loop effective action around the supersymmetric fuzzy sphere by the use of the background field method and show the quantum stability of the giant graviton. Also, the instability of the non-supersymmetric fuzzy sphere is proven.
126190271
THE CLASSICAL EQUIVALENCE OF MONODROMY MATRICES IN SQUASHED SIGMA MODEL
We show Yangian and quantum affine symmetries are realized in two-dimensional non-linear sigma models with squashed spheres target spaces. According to these symmetries, there are two descriptions for the classical dynamics. In each description, a Lax pair and the corresponding monodromy matrix are constructed. Both Lax pairs reproduce the same equations of motion and hence they are equivalent. We show the gauge-equivalence by constructing a map between monodromy matrices with the relation of spectral parameters.
119480216
Chiral Phase Transitions in QED at Finite Temperature Dyson-Schwinger Equation Analysis in the Real Time Hard-Thermal-Loop Approximation
In order to clarify the essential thermal effects that govern the chiral phase transition at finite temperature, we investigate, in the real-time thermal QED, the consequences of the hard-thermal-loop (HTL) resummed Dyson-Schwinger equation for the physical fermion mass function ΣR. Since ΣR is the mass function of an “unstable” quasi-particle in thermal field theories, it necessarily has non-trivial imaginary parts, together with non-trivial wave function renormalization constants. Analyses so far have completely disregarded this fact, despite it being one of the basic outcomes of thermal field theory. The “approximation”, which ignores the imaginary parts of ΣR, gives (non-trivial) constraint equations to be solved simultaneously. For this reason, this approximation cannot be applied consistently except in the trivial case, ΣR = 0. In the present analysis we correctly take this fact into account, and study, in the ladder approximation, the effect of the HTL resummed gauge boson propagator. Our results obtained using numerical analysis, reveal two facts: i) the chiral phase transition is of second order, since the fermion mass is dynamically generated at a critical value of the temperature Tc, or at a critical coupling constant αc, without any discontinuity; and ii) the critical temperature Tc at a fixed value of α is significantly lower than that obtained previously, which means that the restoration of chiral symmetry occurs at a lower temperature than previously expected. The second fact shows the importance of correctly incorporating the essential thermal effect into the analysis of the chiral phase transition. A procedure for taking account of the gauge invariance in the present approximation is also discussed.