Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar (open access)

Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar

We present experimental measurements of branching fraction and longitudinal polarization fraction in charmless hadronic B decays into vector, axial vector and tensor final states with the final dataset of BABAR. Measurements of such kind of decays are a powerful tool both to test the Standard Model and search possible sources of new physics. In this document we present a short review of the last experimental results at BABAR concerning charmless quasi two-body decays in final states containing particles with spin 1 or spin 2 and different parities. This kind of decays has received considerable theoretical interest in the last few years and this particular attention has led to interesting experimental results at the current b-factories. In fact, the study of longitudinal polarization fraction f{sub L} in charmless B decays to vector vector (VV), vector axial-vector (VA) and axial-vector axial-vector (AA) mesons provides information on the underlying helicity structure of the decay mechanism. Naive helicity conservation arguments predict a dominant longitudinal polarization fraction f{sub L} {approx} 1 for both tree and penguin dominated decays and this pattern seems to be confirmed by tree-dominated B {yields} {rho}{rho} and B{sup +} {yields} {Omega}{rho}{sup +} decays. Other penguin dominated decays, instead, show a different …
Date: April 6, 2012
Creator: Gandini, Paolo
Object Type: Article
System: The UNT Digital Library
Emerging Energy-efficiency and CO{sub 2} Emission-reduction Technologies for Cement and Concrete Production (open access)

Emerging Energy-efficiency and CO{sub 2} Emission-reduction Technologies for Cement and Concrete Production

Globally, the cement industry accounts for approximately 5 percent of current anthropogenic carbon dioxide (CO{sub 2}) emissions. World cement demand and production are increasing significantly, leading to an increase in this industry's absolute energy use and CO{sub 2} emissions. Development of new energy-efficiency and CO{sub 2} emission-reduction technologies and their deployment in the market will be key for the cement industry's mid- and long-term climate change mitigation strategies. This report is an initial effort to compile available information on process description, energy savings, environmental and other benefits, costs, commercialization status, and references for emerging technologies to reduce the cement industry's energy use and CO{sub 2} emissions. Although studies from around the world identify a variety of sector-specific and cross-cutting energy-efficiency technologies for the cement industry that have already been commercialized, information is scarce and/or scattered regarding emerging or advanced energy-efficiency and low-carbon technologies that are not yet commercialized. This report consolidates available information on nineteen emerging technologies for the cement industry, with the goal of providing engineers, researchers, investors, cement companies, policy makers, and other interested parties with easy access to a well-structured database of information on these technologies.
Date: April 6, 2012
Creator: Hasanbeigi, Ali; Price, Lynn & Lin, Elina
Object Type: Report
System: The UNT Digital Library
Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters (open access)

Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters

Feedback control of a low-frequency azimuthal wave known as a "rotating spoke" in the ExB discharge of a cylindrical Hall thruster was demonstrated. The rotating spoke is an m=1 azimuthal variation in density, electron temperature, and potential that rotates at about 10% of the local E x B electron rotation speed. It causes increased electron transport across the magnetic field and is suspected to be an ionization wave. Feedback control of this wave required special consideration because, although it causes a rotating azimuthal variation in the current density to the anode, it does not show up as a signal in the total thruster discharge current. Therefore, an extra source of information was needed to track the oscillation, which was addressed by using a special anode that was split azimuthally into four segments. The current to each segment oscillates as the rotating spoke passes over it, and feedback is accomplished by resistors connected in series with each anode segment which cause the voltage on a segment to decrease in proportion to the current through that segment. The feedback resulted in the disappearance of a coherent azimuthal wave and a decrease in the time-averaged total discharge current by up to 13.2%.
Date: April 6, 2012
Creator: Martin E. Griswold, C.L. Ellison, Y. Raitses and N.J. Fisch
Object Type: Report
System: The UNT Digital Library
A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures (open access)

A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures

A generalized, computationally tractable fluid model for capturing the effects of neutral particles in plasmas is derived. The model derivation begins with Boltzmann equations for singly charged ions, electrons, and a single neutral species. Electron-impact ionization, radiative recombination, and resonant charge exchange reactions are included. Moments of the reaction collision terms are detailed. Moments of the Boltzmann equations for electron, ion, and neutral species are combined to yield a two-component plasma-neutral fluid model. Separate density, momentum, and energy equations, each including reaction transfer terms, are produced for the plasma and neutral equations. The required closures for the plasma-neutral model are discussed.
Date: April 6, 2012
Creator: Meier, E T & Shumlak, U
Object Type: Article
System: The UNT Digital Library
Hadronic Contributions to R and G-2 from Initial-State-Radiation Data (open access)

Hadronic Contributions to R and G-2 from Initial-State-Radiation Data

I review the recent efforts to improve the precision of the prediction of the anomalous moment of the muon, in particular of the hadronic contribution of the vacuum polarization, which is the contribution with the largest uncertainty. Focus is given to the recent result for e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -} by the BaBar collaboration, obtained using events with radiation in the initial state.
Date: April 6, 2012
Creator: Bernard, Denis, 1 & Polytechnique, /Ecole
Object Type: Article
System: The UNT Digital Library
Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves (open access)

Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves

We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the Constitution set and, combined with a BAO prior, produces 1 + w = 0.013{sub -0.068}{sup +0.066} (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largest role. We use four light-curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R{sub V} = 3.1), and MLCS2k2 (R{sub V} = 1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 < {Delta} < 1.2. MLCS2k2 with R{sub V} = 3.1 overestimates host-galaxy extinction while R{sub V} {approx} 1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2{sigma}, suggesting that …
Date: April 6, 2012
Creator: Hicken, Malcolm; U., /Harvard-Smithsonian Ctr. Astrophys. /Harvard; Wood-Vasey, W.Michael; U., /Pittsburgh; Blondin, Stephane; Observ., /European Southern et al.
Object Type: Article
System: The UNT Digital Library
ISR Physics at BaBar (open access)

ISR Physics at BaBar

A method of measuring e{sup +}e{sup -} annihilation cross sections at low energy {radical}s < 5 GeV, using initial-state radiation, is described. Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass energy, obtained via ISR, are presented. The cross sections are measured for many processes e{sup +}e{sup -} {yields} 3{pi}, 4{pi}, 2K{pi}, 2K2{pi}, 4K, p{bar p}, {Lambda}{Lambda}, D{bar D}, ... . From the measured cross sections the parameters of known resonances are improved, the baryons form factors are derived and compared with theory predictions. New states, e.g; Y(4260) and Y(2175), for which the internal structure is not yet established, are observed.
Date: April 6, 2012
Creator: Serednyakov, S .I.
Object Type: Article
System: The UNT Digital Library
A Little Solution to the Little Hierarchy Problem: A Vector-like Generation (open access)

A Little Solution to the Little Hierarchy Problem: A Vector-like Generation

We present a simple solution to the little hierarchy problem in the minimal supersymmetric standard model: a vectorlike fourth generation. With O(1) Yukawa couplings for the new quarks, the Higgs mass can naturally be above 114 GeV. Unlike a chiral fourth generation, a vectorlike generation can solve the little hierarchy problem while remaining consistent with precision electroweak and direct production constraints, and maintaining the success of the grand unified framework. The new quarks are predicted to lie between 300-600 GeV and will thus be discovered or ruled out at the LHC. This scenario suggests exploration of several novel collider signatures.
Date: April 6, 2012
Creator: Graham, Peter W.; Ismail, Ahmed; /Stanford U., Phys. Dept.; Rajendran, Surjeet; /MIT, LNS /SLAC /Stanford U., Phys. Dept.; Saraswat, Prashant et al.
Object Type: Article
System: The UNT Digital Library
PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats (open access)

PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats

We have designed an 'ultimate' storage ring for the PEP-X light source that achieves the diffraction limited emittances (at 1.5 {angstrom}) of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10{sup 22} [photons/s/mm{sup 2}/mrad{sup 2}/0.1% BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes PEP-X competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.
Date: April 6, 2012
Creator: Cai, Yunhai; Bane, Karl; Hettel, Robert; Nosochkov, Yuri & Wang, Min-Huey
Object Type: Article
System: The UNT Digital Library
Reaction Mechanisms of Pair Transfer (open access)

Reaction Mechanisms of Pair Transfer

None
Date: April 6, 2012
Creator: Thompson, I. J. & Brown, B. A.
Object Type: Book
System: The UNT Digital Library
Selected Topics in Tau Physics from BaBar (open access)

Selected Topics in Tau Physics from BaBar

Selected results from {tau} analyses performed using the BABAR detector at the SLAC National Accelerator Laboratory are presented. A precise measurement of the {tau} mass and the {tau}{sup +}{tau}{sup -} mass difference is undertaken using the hadronic decay mode {tau}{sup {+-}} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup {+-}}{nu}{sub {tau}}. In addition an investigation into the strange decay modes {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}} is also presented, including a fit to the {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}} invariant mass spectrum. Precise values for M(K*(892)) and {Lambda}(K*(892)) are obtained.
Date: April 6, 2012
Creator: Paramesvaran, S. & /Royal Holloway, U. of London
Object Type: Article
System: The UNT Digital Library
Stress-Energy Tensor Induced by Bulk Dirac Spinor in Randall-Sundrum Model (open access)

Stress-Energy Tensor Induced by Bulk Dirac Spinor in Randall-Sundrum Model

None
Date: April 6, 2012
Creator: Shao, Shu-heng; /Taiwan, Natl. Taiwan U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park; Gu, Je-An & /Taiwan, Natl. Taiwan U.
Object Type: Article
System: The UNT Digital Library
Study of the D0 \to Pi Pi- Pi0 Decay at BaBar (open access)

Study of the D0 \to Pi Pi- Pi0 Decay at BaBar

The Dalitz-plot of the decay D{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0} measured by the BABAR collaboration shows the structure of a final state having quantum numbers I{sup G}J{sup PC} = 0{sup -}0{sup 2-}. An isospin analysis of this Dalitz-plot finds that the fraction of the I = 0 contribution is about 96%. This high I = 0 contribution is unexpected because the weak interaction violates the isospin.
Date: April 6, 2012
Creator: Gaspero, Mario
Object Type: Article
System: The UNT Digital Library
Superpartner Mass Measurement with 1D Decomposed MT2 (open access)

Superpartner Mass Measurement with 1D Decomposed MT2

None
Date: April 6, 2012
Creator: Konar, Partha; U., /Florida; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun et al.
Object Type: Article
System: The UNT Digital Library