125696689
High-resolution study of Gamow-Teller transitions via the Fe-54(He-3, t)Co-54 reaction
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.
121478239
Breakup of B-8 at sub-Coulomb energies
2724111
Direct measurement of the L/K ratio in (7)Be electron capture.
The ratio of L- to K-shell electron captures in light nuclei is particularly sensitive to electron overlap and exchange effects. Calculations of these effects in (7)Be disagree by more than 20%. We report a measurement of the L/K ratio in (7)Be, using a cryogenic microcalorimeter which clearly separates L- and K-shell captures. The obtained L/K ratio of 0.040(6) is less than half that of existing predictions for free (7)Be. The discrepancy is likely due to in-medium effects distorting the L-shell electron orbitals.
125276782
Search for isovector giant monopole resonances via the Sn-124(He-3,tn) reaction
The (He-3,t) reaction on Sn-124 at E(He-3)=199 MeV and the subsequent decay by neutron emission at backward angles were studied in an attempt to distinguish isovector monopole strength (spin-flip and non-spin-flip) at excitation energies above 25 MeV from the nonresonant continuum. The present approach is based on the assumption that a large fraction of the contributions to the continuum result from quasifree processes and breakup-pickup processes which leave the nucleus in low-lying excited states below the threshold for neutron emission. It was found, however, that even at high "apparent" excitation energies (above 30 MeV) the branching ratio for decay by neutrons was as high as similar to 50%, indicating that a large part of the nonresonant continuum may not be due to quasifree processes involving valence neutrons only. No evidence for monopole strength at high excitation energies was found, although the experiment had sufficient sensitivity and accuracy to detect isovector monopole strength based on theoretical predictions calculated in the framework of normal-mode collective excitations and the distorted-wave Born approximation.
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.
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.
118055903
New Measurements of Rare K0L and pi0 Decays from Fermilab E799
67837531
Hawking-Page transition in holographic massive gravity
We study the Hawking-Page transition in a holographic model of field theories with momentum dissipation. We find that the deconfinement temperature strictly decreases as momentum dissipation is increased. For sufficiently strong momentum dissipation, the critical temperature goes to zero, indicating a zero-temperature deconfinement transition in the dual field theory.
18134055
Localized shocks
A bstractWe study products of precursors of spatially local operators, Wxntn⋅⋅⋅Wx1t1$$ {W_x}_{{}_n}(tn)\cdot \cdot \cdot {W}_{x_1}\left({t}_1\right) $$, where Wx(t) = e− iHtWxeiHt. Using chaotic spin-chain numerics and gauge/gravity duality, we show that a single precursor fills a spatial region that grows linearly in t. In a lattice system, products of such operators can be represented using tensor networks. In gauge/gravity duality, they are related to Einstein-Rosen bridges supported by localized shock waves. We find a geometrical correspondence between these two descriptions, generalizing earlier work in the spatially homogeneous case.
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.