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We show that the predicted primordial helium production is significantly reduced when new measurements of the neutron lifetime and the implied enhancement in the weak reaction rates are included in big-bang nucleosynthesis. Therefore, even if a narrow uncertainty in the observed helium abundance is adopted, this brings the constraint on the baryon-to-photon ratio from BBN and the observed helium into better accord with the independent determination of the baryon content deduced from the WMAP spectrum of power fluctuations in the cosmic microwave background, and measurements of primordial deuterium in narrow-line quasar absorption systems at high redshift.

We formulate and study a strong harmonic structure under which eigenvalues of the Laplacian on a p.c.f, self-similar set are completely determined according to the dynamical system generated by a rational function. We then show that, with some additional assumptions, the eigenvalue counting function p(A) behaves so wildly that p()~) does not vary regularly, and the ratio p(~)/)t ds/2 is bounded but non-convergent as A q cr where ds is the spectral dimension of the p.c.f, self-similar set.

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We work with increasing finite sets Vm called pre-gaskets approximating the finite Sierpinski gasket located in R N-t (N >_ 3). The eigenvalues of the discrete Laplacian on "Cm under the Dirichlet and Neumann boundary conditions are completely determined using the decimation method due to Rammal.The finite Sierpinski gasket located in the Euclidean N -1 space R N-1 (N >_ 3) is the closure of the union V, of increasing finite sets V,,, (see below for precise definition). We call V,,~ the (m-th step) pre, gasket and we consider a difference operator Hin on Vm corresponding to the simple random walk on Vm.The purpose of this paper is to determine completely the eigenvalues of Hin including their multiplicities under the Dirichlet boundary condigion (Theorem 2.1) and under the Neumann boundary condition (Theorem 3.1). The structure of eigenvalues of H,,, is essentially known owing to the decimation method of RammalToulouse [2] (see also Rammal [3]) relating the eigenvalues of Hin to those of Hin-1 by the quadratic map ~(x) = x(N+2-x). We reproduce the method in Proposition 2.2. Before proving Theorem 2.1 however, we need first to identify the multiplicities of eigenvalues 2, 2N and N + 2, which are excepted in Proposition 2.2. A similar step is necessary in proving Theorem 3.1.Recently Kigami [1] introduced the Laplacian 91 on the Sierpinski gasket as a suitable renormalized limit of Hin as m -* oo. The Dirichlet problem and the Poisson equation associated with A are then solved explicitly. In the present paper, we employ those notations and relations in [1] concerning pre-gaskets. In the forthcoming paper, we shall apply the present result to decide the spectrum and the integrated density of states for Kigami's Laplacian.We now prepare preliminary notions and relations from [1].For Pi E R N-l, i = 1,2,..., N, such that PiPa, j = 2,.. 9 N, are independent, we let i=2 i=29 The aughor would like to thank Professor M. Pukushima and the referee for the mosg helpful suggestions.

We have measured the cross section of the 7 Be͑ p, g͒ 8 B reaction for E c.m. 185.8, 134.7, and 111.7 keV using a radioactive 7 Be target (132 mCi). Single and coincidence spectra of b 1 and a particles from 8 B and 8 Be ‫ء‬ decay, respectively, were measured using a large acceptance spectrometer. The zero energy S factor inferred from these data is 18.5 6 2.4 eV b and a weighted mean value of 18.8 6 1.7 eV b (theoretical uncertainty included) is deduced when combining this value with our previous results at higher energies.

The cross section of 12 C+ 12 C fusion reactions determines the conditions of carbon ignition in stars. The presence of structures, which are likely to extend to low energies, makes the extrapolation of data collected at high energy to the stellar energy difficult and potentially inaccurate, so a direct measurement is desirable. Here we report on an extremely improbable two-step background process which prohibits the measurement of the 12 C(12 C,p) 23 Na carbon fusion reaction at low energies in the presence of deuterium contamination. It appears that with a modified setup and selected targets reliable measurements down to E cm =2.0 MeV are possible.. 11th Symposium on Nuclei in the Cosmos-NIC XI

Photoneutron cross sections were measured for the seven stable samarium isotopes 144,147,148,149,150,152,154 Sm near the neutron threshold with quasi-monochromatic laser-Compton scattering γ rays. Our photoneutron cross sections are found to be low by 20%-37% relative to existing data. The photoneutron data are analyzed with the TALYS reaction code by considering the Skyrme Hartree-Fock-Bogoliubov (HFB) plus quasiparticle random phase approximation (QRPA) model and the axially symmetric deformed Gogny HFB plus QRPA model of the E1 γ -ray strength. Using the γ -ray strength function constrained by the present photoneutron data, we made a thorough analysis of the reverse (n,γ ) cross sections including the radioactive nucleus 151 Sm with a half-life of 90 yr. The radiative neutron capture cross section for 153 Sm with the half-life of 1.928 d is deduced with the γ -ray strength function method.