Model Independent Bounds on Kinetic Mixing (open access)

Model Independent Bounds on Kinetic Mixing

New Abelian vector bosons can kinetically mix with the hypercharge gauge boson of the Standard Model. This letter computes the model independent limits on vector bosons with masses from 1 GeV to 1 TeV. The limits arise from the numerous e{sup +}e{sup -} experiments that have been performed in this energy range and bound the kinetic mixing by {epsilon} {approx}< 0.03 for most of the mass range studied, regardless of any additional interactions that the new vector boson may have.
Date: August 22, 2011
Creator: Hook, Anson; Izaguirre, Eder & Wacker, Jay G.
System: The UNT Digital Library
CP Violation Results from B Decays at BaBar (open access)

CP Violation Results from B Decays at BaBar

In the present paper we review recent experimental results from the BABAR experiment concerning the measurement of the CKM angles. A particular highlight is given to the novel independent determination of the angle {alpha} from B{sup 0} {yields} a{sub 1}(1260){sup {+-}}{pi}{sup {-+}} and to the recent full-luminosity updates of several angle {gamma} measurements.
Date: August 22, 2011
Creator: Biassoni, Pietro
System: The UNT Digital Library
On the behavior of Bronsted-Evans-Polanyi Relations for Transition Metal Oxides (open access)

On the behavior of Bronsted-Evans-Polanyi Relations for Transition Metal Oxides

Versatile Broensted-Evans-Polanyi (BEP) relations are found from density functional theory for a wide range of transition metal oxides including rutiles and perovskites. For oxides, the relation depends on the type of oxide, the active site and the dissociating molecule. The slope of the BEP relation is strongly coupled to the adsorbate geometry in the transition state. If it is final state-like the dissociative chemisorption energy can be considered as a descriptor for the dissociation. If it is initial state-like, on the other hand, the dissociative chemisorption energy is not suitable as descriptor for the dissociation. Dissociation of molecules with strong intramolecular bonds belong to the former and molecules with weak intramolecular bonds to the latter group. We show, for the prototype system La-perovskites, that there is a 'cyclic' behavior in the transition state characteristics upon change of the active transition metal of the oxide.
Date: August 22, 2011
Creator: Vojvodic, Aleksandra
System: The UNT Digital Library
A GMBCG Galaxy Cluster Catalog of 55,424 Rich Clusters from SDSS DR7 (open access)

A GMBCG Galaxy Cluster Catalog of 55,424 Rich Clusters from SDSS DR7

We present a large catalog of optically selected galaxy clusters from the application of a new Gaussian Mixture Brightest Cluster Galaxy (GMBCG) algorithm to SDSS Data Release 7 data. The algorithm detects clusters by identifying the red sequence plus Brightest Cluster Galaxy (BCG) feature, which is unique for galaxy clusters and does not exist among field galaxies. Red sequence clustering in color space is detected using an Error Corrected Gaussian Mixture Model. We run GMBCG on 8240 square degrees of photometric data from SDSS DR7 to assemble the largest ever optical galaxy cluster catalog, consisting of over 55,000 rich clusters across the redshift range from 0.1 < z < 0.55. We present Monte Carlo tests of completeness and purity and perform cross-matching with X-ray clusters and with the maxBCG sample at low redshift. These tests indicate high completeness and purity across the full redshift range for clusters with 15 or more members.
Date: August 22, 2011
Creator: Hao, Jiangang; McKay, Timothy A.; Koester, Benjamin P.; Rykoff, Eli S.; Rozo, Eduardo; Annis, James et al.
System: The UNT Digital Library
Applications of AdS/QCD and Light-Front Holography to Baryon Physics (open access)

Applications of AdS/QCD and Light-Front Holography to Baryon Physics

The correspondence between theories in anti-de Sitter space and field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. These equations, for both mesons and baryons, give a very good representation of the observed hadronic spectrum, including a zero mass pion. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The meson and baryon wavefunctions derived from light-front holography and AdS/QCD also have remarkable phenomenological features, including predictions for the electromagnetic form factors and decay constants. The approach can be systematically improved using light-front Hamiltonian methods. Some novel features of QCD for baryon physics are also discussed.
Date: August 22, 2011
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
System: The UNT Digital Library
Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations (open access)

Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations

Facility for Advanced Accelerator Experimental Tests (FACET) in SLAC will be used to study plasma wakefield acceleration. FLUKA Monte Carlo code was used to design a maze wall to separate FACET project and LCLS project to allow persons working in FACET side during LCLS operation. Also FLUKA Monte Carlo code was used to design the shielding for FACET dump to get optimum design for shielding both prompt and residual doses, as well as reducing environmental impact. FACET will be an experimental facility that provides short, intense pulses of electrons and positrons to excite plasma wakefields and study a variety of critical issues associated with plasma wakefield acceleration [1]. This paper describes the FACET beam parameters, the lay-out and its radiological issues.
Date: August 22, 2011
Creator: Mao, X.S.; Leitner, M.Santana & Vollaire, J.
System: The UNT Digital Library
Sources of the Radio Background Considered (open access)

Sources of the Radio Background Considered

We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed …
Date: August 22, 2011
Creator: Singal, J.; Stawarz, L.; Lawrence, A. & Petrosian, V.
System: The UNT Digital Library
Aerosol Imaging with a Soft X-ray Free Electron Laser (open access)

Aerosol Imaging with a Soft X-ray Free Electron Laser

Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.
Date: August 22, 2011
Creator: Bogan, Michael J.; /SLAC /LLNL, Livermore; Boutet, Sebastien; /SLAC National Accelerator Laboratory; Chapman, Henry N.; U., /DESY /Hamburg et al.
System: The UNT Digital Library
On the Influence of Shrub Height and Expansion on Boreal Climate (open access)

On the Influence of Shrub Height and Expansion on Boreal Climate

None
Date: August 22, 2011
Creator: Bonfils, C.; Phillips, T.; Lawrence, D.; Cameron-Smith, P.; Riley, W. & Subin, Z.
System: The UNT Digital Library
Stimulated forward Raman scattering in large scale-length laser-produced plasmas (open access)

Stimulated forward Raman scattering in large scale-length laser-produced plasmas

None
Date: August 22, 2011
Creator: Niemann, C; Berger, R L; Divol, L; Kirkwood, R K; Moody, J D; Sorce, C M et al.
System: The UNT Digital Library
An apparatus for the characterization of warm, dense deuterium with inelastic x-ray scattering (open access)

An apparatus for the characterization of warm, dense deuterium with inelastic x-ray scattering

None
Date: August 22, 2011
Creator: Davis, P.; Collins, G.; Doeppner, T.; Glenzer, S. H.; Falcone, R. W.; Rygg, J. R. et al.
System: The UNT Digital Library
Correlated Leading Baryon-antibaryon Production in e+e- to ccbar to Lambda_c+ antiLambda_c- X (open access)

Correlated Leading Baryon-antibaryon Production in e+e- to ccbar to Lambda_c+ antiLambda_c- X

We present a study of 649 {+-} 35 e{sup +}e{sup -} {yields} c{bar c} events produced at {radical}s {approx} 10.6 GeV containing both a {Lambda}{sub c}{sup +} baryon and a {bar {Lambda}}{sub c}{sup -} antibaryon. The number observed is roughly four times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and {bar c} are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 {+-} 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.
Date: August 22, 2011
Creator: Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
System: The UNT Digital Library
Search for CP Violation in the Decay D+/- to Ks pi+/- (open access)

Search for CP Violation in the Decay D+/- to Ks pi+/-

We report on a search for CP violation in the decay D{sup {+-}} {yields} K{sub S}{sup 0}{pi}{sup {+-}} using a data set corresponding to an integrated luminosity of 469 fb{sup -1} collected with the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay rate asymmetry A{sub CP} is determined to be (-0.44 {+-} 0.13(stat) {+-} 0.10(syst))%, consistent with zero at 2.7 {sigma} and with the standard model prediction of (-0.332 {+-} 0.006)%. This is currently the most precise measurement of this parameter.
Date: August 22, 2011
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
System: The UNT Digital Library
Search for CP Violation using T-odd Correlations in D+ to K+K0spi+pi- and DS+ to K+K0spi+pi- Decays (open access)

Search for CP Violation using T-odd Correlations in D+ to K+K0spi+pi- and DS+ to K+K0spi+pi- Decays

We search for CP violation in a sample of 20,000 Cabibbo-suppressed decays, D{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}, and 30,000 Cabibbo-favored decays, D{sub s}{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}. We use 520 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energies near 10.6 GeV. We search for CP violation in the difference between the T-odd asymmetries obtained using triple product correlations of the D+ (D{sub s}{sup +}) and D{sup -} (D{sub s}{sup -}) decays, respectively. The T violation parameter values obtained are {Alpha}{sub T} (D{sup +}) = (-12.0 {+-} 10.0{sub stat} {+-} 4.6{sub syst}) x 10{sup -3} and {Alpha}{sub T}(D{sub s}{sup +}) = (-13.6 {+-} 7.7{sub stat} {+-} 3.4{sub syst}) x 10{sup -3}, which are consistent with the Standard Model expectations.
Date: August 22, 2011
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
System: The UNT Digital Library
Study of B to X \gamma Decays and Determination of |V_{td}/V_{ts}| (open access)

Study of B to X \gamma Decays and Determination of |V_{td}/V_{ts}|

Using a sample of 471 million B{bar B} events collected with the BABAR detector, we study the sum of seven exclusive final states B {yields} X{sub s(d){gamma}}, where X{sub s(d)} is a strange (non-strange) hadronic system with a mass of up to 2.0 GeV/c{sup 2}. After correcting for unobserved decay modes, we obtain a branching fraction for b {yields} d{gamma} of (9.2 {+-} 2.0(stat.) {+-} 2.3(syst.)) x 10{sup -6} in this mass range, and a branching fraction for b {yields} s{gamma} of (23.0 {+-} 0.8(stat.) {+-} 3.0(syst.)) x 10{sup -5} in the same mass range. We find {Beta}(b{yields}d{gamma})/{Beta}(b{yields}s{gamma}) = 0.040 {+-} 0.009(stat.) {+-} 0.010(syst.), from which we determine |V{sub td}/V{sub ts}| = 0.199 {+-} 0.022(stat.) {+-} 0.024(syst.) {+-} 0.002(th.).
Date: August 22, 2011
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
System: The UNT Digital Library