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Dalitz Plot Analysis of B- -> D+ pi- pi- (open access)

Dalitz Plot Analysis of B- -> D+ pi- pi-

The author reports on a Dalitz plot analysis of B{sup -} {yields} D{sup +}{pi}{sup -}{pi}{sup -} decays, based on a sample of about 383 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. They find the total branching fraction of the three-body decay: {Beta}(B{sup -} {yields} D{sup +} {pi}{sup -}{pi}{sup -}) = (1.08 {+-} 0.01 {+-} 0.05) x 10{sup -3}. the masses and widths of D*{sub 2}{sup 0} and D*{sub 0}{sup 0}, the 2{sup +} and 0{sup +} c{bar u} P-wave states decaying to D{sup +}{pi}{sup -}, are measured: m{sub D*{sub 2}{sup 0}} = (2460.4 {+-} 1.2 {+-} 1.2 {+-} 1.9) MeV/c{sup 2}, {Lambda}{sub D*{sub 2}{sup 0}} = (41.8 {+-} 2.5 {+-} 2.1 {+-} 2.0) MeV, m{sub D*{sub 0}{sup 0}} = (2297 {+-} 8 {+-} 5 {+-} 19) MeV/c{sup 2} and {Lambda}{sub D*{sub 0}{sup 0}} = (273 {+-} 12 {+-} 17 {+-} 45) MeV. The stated errors reflect the statistical and systematic uncertainties, and the uncertainty related to the assumed composition of signal events and the theoretical model.
Date: January 29, 2009
Creator: Aubert, B.
System: The UNT Digital Library
Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated? (open access)

Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model …
Date: January 29, 2009
Creator: Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal et al.
System: The UNT Digital Library
Observation of B Meson Decays to omegaK* and Improved Measurements for omegarho and omegaf0 (open access)

Observation of B Meson Decays to omegaK* and Improved Measurements for omegarho and omegaf0

We present measurements of B meson decays to the final states {omega}K*, {omega}{rho}, and {omega}f{sub 0}, where K* indicates a spin 0, 1, or 2 strange meson. The data sample corresponds to 465 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. B meson decays involving vector-scalar, vector-vector, and vector-tensor final states are analyzed; the latter two shed new light on the polarization of these final states. We measure the branching fractions for nine of these decays; five are observed for the first time. For most decays we also measure the charge asymmetry and, where relevant, the longitudinal polarization f{sub L}.
Date: January 29, 2009
Creator: Aubert, B.
System: The UNT Digital Library
Laminated Amorphous Silicon Neutron Detector (pre-print) (open access)

Laminated Amorphous Silicon Neutron Detector (pre-print)

An internal R&D project was conducted at the Special Technologies Laboratory (STL) of National Security Technologies, LLC (NSTec), to determine the feasibility of developing a multi-layer boron-10 based thermal neutron detector using the amorphous silicon (AS) technology currently employed in the manufacture of liquid crystal displays. The boron-10 neutron reaction produces an alpha that can be readily detected. A single layer detector, limited to an approximately 2-micron-thick layer of boron, has a theoretical sensitivity of about 3%; hence a thin multi-layer device with high sensitivity can theoretically be manufactured from single layer detectors. Working with National Renewable Energy Laboratory (NREL), an AS PiN diode alpha detector was developed and tested. The PiN diode was deposited on a boron-10 coated substrate. Testing confirmed that the neutron sensitivity was nearly equal to the theoretical value of 3%. However, adhesion problems with the boron-10 coating prevented successful development of a prototype detector. Future efforts will include boron deposition work and development of integrated AS signal processing circuitry.
Date: January 29, 2009
Creator: Harry McHugh, Howard Branz, Paul Stradins, and Yueqin Xu
System: The UNT Digital Library