120103770
Determination of the density distribution and the correlation of halo neutrons in 11Li
Interaction cross sections (σ1) and transverse momentum Pt distributions of 9Li fragments in 11Li reactions were measured 1467 using p and d targets at 800A MeV, and Be and C targets at 400A MeV. The density distribution of the 11Li nucleus has been determined for the first time from these σI's. It is confirmed that only a distribution with a long tail (halo) consistently reproduces the observed data. From a combined analysis of Pt distributions of 9Li and of neutrons, the momentum correlation of the two halo neutrons was extracted. It suggests that these neutrons have a strong tendency to move in the same direction.
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.
102941799
Experimental study of neutron rich helium isotopes
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.
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.
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.
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.
119110617
Spin–isospin response of deformed neutron-rich nuclei in a self-consistent Skyrme energy-density-functional approach
We develop a new framework of the self-consistent deformed proton-neutron quasiparticle-random-phase approximation (pnQRPA), formulated in the Hartree-Fock-Bogoliubov (HFB) single-quasiparticle basis. The same Skyrme force is used in both the HFB and pnQRPA calculations except in the proton-neutron particle-particle channel, where an S=1 contact force is employed. Numerical application is performed for Gamow-Teller (GT) strength distributions and $\beta$-decay rates in the deformed neutron-rich Zr isotopes located around the path of the rapid-neutron-capture process nucleosynthesis. It is found that the GT strength distributions are fragmented due to deformation. Furthermore we find that the momentum-dependent terms in the particle-hole residual interaction leads to a stronger collectivity of the GT giant resonance. The T=0 pairing enhances the low-lying strengths cooperatively with the T=1 pairing correlation, which shortens the $\beta$-decay half lives by at most an order of magnitude. The new calculation scheme reproduces well the observed isotopic dependence of the $\beta$-decay half lives of deformed $^{100-110}$Zr isotopes.
55506208
N-Point Vertex Functions, Ward-Takahashi Identities and Dyson-Schwinger Equations in Thermal QCD/QED in the Real Time Hard-Thermal-Loop Approximation
In this paper we calculate the n-point hard-thermal-loop (HTL) vertex functions in QCD/QED for n= 2, 3 and 4 in the physical representation using the real time formalism (RTF). The result reveals that the n-point HTL vertex functions can be classified into two groups, a) those with odd numbers of external retarded indices, and b) those with even numbers of external retarded indices. The n-point HTL vertex functions with one retarded index, which obviously belong to group a), are identical to the HTL vertex functions that appear in the imaginary time formalism (ITF). All the HTL vertex functions belonging to group a) are O(g 2 T 2 ) and satisfy among them the simple QED-type Ward-Takahashi identities, as in the ITF. Those vertex functions belonging to group b) never appear in the ITF, their existence being characteristic of the RTF, and their HTLs exhibit high temperature behavior that is O(g 2 T 3 ), one power of T higher than usual. Despite this difference, we were able to verify that those HTL vertex functions belonging to group b) also satisfy among themselves the QED-type Ward-Takahashi identities, thus guaranteeing the gauge invariance of the HTLs in the real time thermal QCD/QED. As an application, we explicitly derive the HTL resummed Dyson-Schwinger equations for the physical fermion mass function and for the gauge boson polarization tensor in thermal QCD/QED.
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.
119229699
Structure of a thermal quasifermion in the QCD/QED Medium
In this paper we carried out a nonperturbative analysis of a thermal quasifermion in the chiral symmetric thermal QCD/QED medium by studying its self-energy function through the Dyson-Schwinger equation with the hard-thermal-loop resummed improved ladder kernel. Our analysis reveals several interesting results, two in some of which may force us to change the image of thermal quasifermions: (1) The thermal mass of a quasifermion begins to decrease as the strength of the coupling gets stronger and finally disappears in the strong coupling region, thus showing a property of a massless particle, and (2) its imaginary part (i.e., the decay width) persists to have $O(g^2T \log(1/g))$ behavior. These results suggest that in the recently produced strongly coupled quark-gluon plasma, the thermal mass of a quasiquark should vanish. Taking into account the largeness of the imaginary part, it seems very hard for a quark to exist as a qausiparticle in the strongly coupled quark-gluon plasma phase. Other important findings are as follows: (3) The collective plasmino mode disappears also in the strongly coupled system, and (4) there exists an ultrasoft third peak in the quasifermion spectral density at least in the weakly coupled QED/QCD plasma, indicating the existence of the ultrasoft fermionic mode.