118055903
New Measurements of Rare K0L and pi0 Decays from Fermilab E799
119648296
FastSim: A Fast Simulation for the SuperB Detector
We have developed a parameterized (fast) simulation for detector optimization and physics reach studies of the proposed SuperB Flavor Factory in Italy. Detector components are modeled as thin sections of planes, cylinders, disks or cones. Particle-material interactions are modeled using simplified cross-sections and formulas. Active detectors are modeled using parameterized response functions. Geometry and response parameters are configured using xml files with a custom-designed schema. Reconstruction algorithms adapted from BaBar are used to build tracks and clusters. Multiple sources of background signals can be merged with primary signals. Pattern recognition errors are modeled statistically by randomly misassigning nearby tracking hits. Standard BaBar analysis tuples are used as an event output. Hadronic B meson pair events can be simulated at roughly 10Hz.
18200063
Masers as Probes of Massive Star Formation in the Nuclear Disk
Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 USAemail: bwhitney@spacescience.orgAbstract.OH(1720 MHz) and methanol masers are now recognized to be excellent probes of theinteractions of supernova remnants with molecular clouds and tracers of massive star formation,respectively. To better understand the nature of star formation activity in the central regionof the Galaxy, we have used these two classes of masers combined with the IRAC and MIPSdata to study prominent sites of ongoing star formation in the nuclear disk. The nuclear diskis characterized by massive GMCs with elevated gas temperatures, compared to their dusttemperatures. We note an association between methanol masers and a class of mid-infrared“green sources”. These highly embedded YSOs show enhanced 4.5µm emission due to excitedmolecular lines.The distribution of methanol masers and supernova remnants suggest a low eﬃciency of starformation (with the exception of Sgr B2), which we believe is due to an enhanced ﬂux of cosmicray electrons impacting molecular clouds in the nuclear disk. We also highlight the importanceof cosmic rays in their ability to heat molecular clouds, and thus increase the gas temperature.Keywords. Masers, supernova remnants, cosmic rays.
119356116
Measurement of the Gamow-Teller strength distribution in Co-58 via the Ni-58(t,He-3) reaction at 115 MeV/nucleon
Electron capture and beta decay play important roles in the evolution of presupernovae stars and their eventual core collapse. These rates are normally predicted through shell-model calculations. Experimentally determined strength distributions from charge-exchange reactions are needed to test modern shell-model calculations. We report on the measurement of the Gamow-Teller strength distribution in Co-58 from the Ni-58(t,He-3) reaction with a secondary triton beam of an intensity of similar to 10(6) pps at 115 MeV/nucleon and a resolution of similar to 250 keV. Previous measurements with the Ni-58(n,p) and the Ni-58(d,He-2) reactions were inconsistent with each other. Our results support the latter. We also compare the results to predictions of large-scale shell-model calculations using the KB3G and GXPF1 interactions and investigate the impact of differences between the various experiments and theories in terms of the weak rates in the stellar environment. Finally, the systematic uncertainties in the normalization of the strength distribution extracted from Ni-58(He-3, t) are described and turn out to be nonnegligible due to large interferences between the Delta L=0,Delta S=1 Gamow-Teller amplitude and the Delta L=2,Delta S=1 amplitude.
118339803
Pion Double Charge Exchange in p-shell Nuclei
Doubly differential cross sections for inclusive pion double charge exchange (DCX) on 6,7Li, 9Be, and 12C have been measured at the Los Alamos Meson Physics Facility with incident positive and negative pions of energies 120, 180, and 240 MeV. These new data, together with our previous studies of DCX on nuclei with A = 3, 4, 16, 40, 103, and 208, provide a detailed picture of the systematics of this reaction over the entire periodic table.
121478239
Breakup of B-8 at sub-Coulomb energies
119068583
Inclusive pion double charge exchange in 4He at intermediate energies
A systematic experimental study of inclusive pion double charge exchange in 4He has been undertaken. The reaction 4He(pi+,pi-)4p was observed at incident energies 120, 150, 180, 240 and 270 MeV; the 4He(pi-,pi+)4n reaction was observed at incident energies 180 and 240 MeV. At each incident energy, the doubly differential cross section was measured at three to five outgoing pion laboratory angles between 25 deg and 130 deg. At each angle, cross sections were measured over the range of outgoing pion energies from 10 MeV up to the kinematic limit for the reaction in which the final state consists of the oppositely charged pion plus four free nucleons. 
The spectra of outgoing pions are strikingly different from those observed for the inclusive double charge exchange reaction in heavier nuclei, but resemble those observed in the (pi-,pi+) reaction in 3He. The forward-angle spectra in the 3He and 4He reactions exhibit a prominent peak at high outgoing pion energies. Interpretation of the peaks in 3He (4He) as a three- (four-)nucleon resonance is ruled out by kinematic analysis. The results of a calculation, wherein the double charge exchange reaction is assumed to proceed as two sequential single charge exchange interactions, suggest that the high-energy peak is naturally explained by this double scattering mechanism. Non-static treatment of the pi-N interactions and the inclusion of nuclear binding effects appear to be important in reproducing the shape of the energy spectra at forward angles.
18279063
On memory in exponentially expanding spaces
A bstractWe examine the degree to which fluctuating dynamics on exponentially expanding spaces remember initial conditions. In de Sitter space, the global late-time configuration of a free scalar field always contains information about early fluctuations. By contrast, fluctuations near the boundary of Euclidean Anti-de Sitter may or may not remember conditions in the center, with a transition at Δ = d/2. We connect these results to literature about statistical mechanics on trees and make contact with the observation by Anninos and Denef that the configuration space of a massless dS field exhibits ultrametricity. We extend their analysis to massive fields, finding that preference for isosceles triangles persists as long as Δ−< d/4.