Properties of thePo208(0+

Abstract

Pion double charge exchange has been used to populate the double isobaric analog state (DIAS) in 208 Po with use of the doubly magic target 208 Pb. The DIAS was found at an excitation energy of 32.46 ±0.17 MeV with a width of 0.85 ±0.40 MeV. The excitation energy of the DIAS can be used along with the energy of the isobaric analog state to determine separately the linear and the quadratic terms of the isobaric-multiplet-mass equation. The resulting linear and quadratic terms are b= -31.6 ±3.7 MeV and c = 0.33 ±0.09 MeV, respectively.

Derivative expansion of the renormalization group in O(N) scalar field theory

“…preservation of quantization of anomalous scaling dimensions after derivative expansion, for certain cutoffs [19,10,4], as we review later). Very encouraging accuracy has been found in the results with this method for the non-perturbative massless quantum field theories of a single scalar field, corresponding to the two and three dimensional Ising model fixed points [19,20], and the infinite sequence of two dimensional multicritical fixed points [20]. These latter results are particularly significant since these calculations lie well outside the practical capabilities of all other standard approximation methods (including lattice methods) [20].…”

“…The derivative expansion for the Legendre effective action with infrared cutoff (this being the one-particle irreducible part of the Wilson/Polchinski effective actions [2]) preserves more of the structure [2,4] (e.g. preservation of quantization of anomalous scaling dimensions after derivative expansion, for certain cutoffs [19,10,4], as we review later). Very encouraging accuracy has been found in the results with this method for the non-perturbative massless quantum field theories of a single scalar field, corresponding to the two and three dimensional Ising model fixed points [19,20], and the infinite sequence of two dimensional multicritical fixed points [20].…”

T=13 double isobaric analog state inCe138via pion-induced double charge exchange

“…Because the width of the IAS increases with A, this hypothesis is easier to test for heavy nuclei. Only one width measurement of a DIAS has been reported previously [8]. Our ability to acquire high-resolution data on a target very much lighter than Pb provides a test of this prediction.…”

“…Pion-induced double charge exchange (DCX) above the b, 3 3 resonance is able to select the DIAS from the large number of lower isospin states forming a background in the continuum. The selectivity has been demonstrated by the observation of the DIAS of Bi [7] and Pb [8]. Figure 1 presents all the published DIAS cross sections at 292 Mev [9,10].…”

Nonperturbative Flow Equations, Low-Energy QCD, and the Chiral Phase Transition

“…Once η Φ ≡ −∂ t ln Z Φ,k is determined [7] in terms of the couplings parameterizing U k this is a partial differential equation for a function U k depending on two variables k and ρ which can be solved numerically [24,25,26,27]. (The Wilson-Fisher fixed point relevant for a second order phase transition (d = 3) corresponds to a scaling solution [28,29] where ∂ t U k = 0.) A suitable truncation of a flow equation of the type Eq.…”