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Geometric Transitions and Dynamical SUSY Breaking

Description: We show that the physics of D-brane theories that exhibit dynamical SUSY breaking due to stringy instanton effects is well captured by geometric transitions, which recast the non-perturbative superpotential as a classical flux superpotential. This allows for simple engineering of Fayet, Polonyi, O'Raifeartaigh, and other canonical models of supersymmetry breaking in which an exponentially small scale of breaking can be understood either as coming from stringy instantons or as arising from the c… more
Date: October 1, 2007
Creator: Aganagic, Mina; Beem, Christopher; Kachru, Shamit & /UC, Berkeley /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of Slice Transverse Emittance Evolution ina Photocathode RF Gun

Description: The slice transverse emittance of an electron beam is of critical significance for an x-ray FEL. In a photocathode RF gun, the slice transverse emittance is not only determined by the emission process, but also influenced strongly by the non-linear space charge effect. In this paper, we study the slice transverse emittance evolution in a photocathode RF gun using a simple model that includes effects of RF acceleration, focusing, and space charge force. The results are compared with IMPACT-T spa… more
Date: October 17, 2007
Creator: Huang, Z.; Ding, Y.; /SLAC; Qiang, J. & /LBL, Berkeley
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Doubling the PEP-II Luminosity in Simulation

Description: Simulations show that luminosity of the PEP-II B-factory can be doubled from its present peak value of 1 x 10{sup 34}cm{sup -2}s{sup -1}. The particle simulation code BBI developed for studying beam-beam interaction was used to perform the simulations. It was first found that the parasitic collisions significantly degrade the simulated luminosity as the beam currents are increased from 3A and 1.7A to 4A and 2.2A in the low and high energy rings, respectively. The effect of changes in various ac… more
Date: June 23, 2006
Creator: Cai, Y.; Seeman, J.; Sonnad, K.; Wienands, U. & /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Sweet Spot Supersymmetry

Description: We find that there is no supersymmetric flavor/CP problem, {mu}-problem, cosmological moduli/gravitino problem or dimension four/five proton decay problem in a class of supersymmetric theories with O(1) GeV gravitino mass. The cosmic abundance of the nonthermally produced gravitinos naturally explains the dark matter component of the universe. A mild hierarchy between the mass scale of supersymmetric particles and electroweak scale is predicted, consistent with the null result of a search for t… more
Date: June 6, 2007
Creator: Ibe, Masahiro; Kitano, Ryuichiro & /SLAC /Stanford U., Phys. Dept.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chiral Gauge Dynamics and Dynamical Supersymmetry Breaking

Description: We study the dynamics of a chiral SU(2) gauge theory with a Weyl fermion in the I = 3/2 representation and of its supersymmetric generalization. In the former, we find a new and exotic mechanism of confinement, induced by topological excitations that we refer to as magnetic quintets. The supersymmetric version was examined earlier in the context of dynamical supersymmetry breaking by Intriligator, Seiberg, and Shenker, who showed that if this gauge theory confines at the origin of moduli space,… more
Date: May 7, 2009
Creator: Poppitz, Erich; U., /Toronto; Unsal, Mithat & U., /SLAC /Stanford
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Retrofitting and the mu Problem

Description: One of the challenges of supersymmetry (SUSY) breaking and mediation is generating a {mu} term consistent with the requirements of electro-weak symmetry breaking. The most common approach to the problem is to generate the {mu} term through a SUSY breaking F-term. Often these models produce unacceptably large B{mu} terms as a result. We will present an alternate approach, where the {mu} term is generated directly by non-perturtative effects. The same non-perturbative effect will also retrofit th… more
Date: August 26, 2010
Creator: Green, Daniel; Weigand, Timo & /SLAC /Stanford U., Phys. Dept.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Calibration of the Nikon 200 for Close Range Photogrammetry

Description: The overall objective of this project is to study the stability and reproducibility of the calibration parameters of the Nikon D200 camera with a Nikkor 20 mm lens for close-range photogrammetric surveys. The well known 'central perspective projection' model is used to determine the camera parameters for interior orientation. The Brown model extends it with the introduction of radial distortion and other less critical variables. The calibration process requires a dense network of targets to be … more
Date: August 25, 2010
Creator: Sheriff, Lassana & /City Coll., N.Y. /SLAC
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Model of gamma sky for the Fermi Gamma-ray Space Telescope (FGST)

Description: A number of important parameters of cosmic-ray distribution, propagation, and interaction in the Milky Way can be predicted through the comparison of measured cosmic-ray and gamma-ray spectra to the spectra of simulated Galaxies. These predictions are made by altering the physical parameters governing Galaxy simulations until a best-fit set of parameters is found. Since the accuracy of this method is limited by the quality of available data, the exceptional precision of recent FGST gamma-ray me… more
Date: August 25, 2010
Creator: McLeod, Andrew & /UC, San Diego /SLAC /KIPAC, Menlo Park
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dynamical Messengers for Gauge Mediation

Description: We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source o… more
Date: August 17, 2011
Creator: Hook, Anson; Torroba, Gonzalo & /SLAC /Stanford U., Phys. Dept.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma

Description: Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indicatio… more
Date: January 6, 2006
Creator: Ozcan, V.E. & /SLAC /Stanford U., Appl. Phys. Dept.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Flux and Photon Spectral Index Distributions of Fermi-LAT Blazars and Contribution to the Extragalactic Gamma-ray Background

Description: We present a determination of the distributions of gamma-ray flux - the so called LogN-LogS relation - and photon spectral index for the 352 blazars detected with a greater than approximately seven sigma detection threshold and located above {+-} 20{sup o} Galactic latitude by the Large Area Telescope of the Fermi Gamma-ray Space Telescope in its first year catalog. Because the flux detection threshold depends on the photon index, the observed raw distributions do not provide the true LogN-LogS… more
Date: December 9, 2011
Creator: Singal, J.; /KIPAC, Menlo Park /SLAC /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Ajello, M. & /KIPAC, Menlo Park /SLAC /Stanford U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Resonance--Continuum Interference in Light Higgs Boson Production at a Photon Collider

Description: We study the effect of interference between the Standard Model Higgs boson resonance and the continuum background in the process {gamma}{gamma} {yields} H {yields} b{bar b} at a photon collider. Taking into account virtual gluon exchange between the final-state quarks, we calculate the leading corrections to the height of the resonance for the case of a light (m{sub H} < 160 GeV) Higgs boson. We find that the interference is destructive and around 0.1-0.2% of the peak height, depending on th… more
Date: January 6, 2009
Creator: Dixon, Lance J.; Sofianatos, Yorgos & /SLAC /Stanford U., Phys. Dept.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Transversity from First Principles in QCD

Description: Transversity observables, such as the T-odd Sivers single-spin asymmetry measured in deep inelastic lepton scattering on polarized protons and the distributions which are measured in deeply virtual Compton scattering, provide important constraints on the fundamental quark and gluon structure of the proton. In this talk I discuss the challenge of computing these observables from first principles; i.e.; quantum chromodynamics, itself. A key step is the determination of the frame-independent light… more
Date: February 16, 2012
Creator: Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Novel QCD Phenomena at the LHeC

Description: The proposed electron-proton/ion collider at CERN, the LHeC, can test fundamental and novel aspects of QCD and electroweak interactions as well as explore physics beyond the standard model over an exceptionally large kinematic range.
Date: June 22, 2011
Creator: Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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800MHz Crab Cavity Conceptual Design For the LHC Upgrade

Description: In this paper, we present an 800 MHz crab cavity conceptual design for the LHC upgrade. The cell shape is optimized for lower maximum peak surface fields as well as higher transverse R/Q. A compact coax-to-coax coupler scheme is proposed to damp the LOM/SOM modes. A two-stub antenna with a notch filter is used as the HOM coupler to damp the HOM modes in the horizontal plane and rejects the operating mode at 800MHz. Multipacting (MP) simulations show that there are strong MP particles at the dis… more
Date: May 26, 2009
Creator: Xiao, Liling; Li, Zenghai; Ng, Cho-Kuen; Seryi, Andrei & /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Higgs Discovery in the Presence of Light CP-Odd Scalars

Description: Many models of electroweak symmetry breaking have an additional light pseudoscalar. If the Higgs boson can decay to a new pseudoscalar, LEP searches for the Higgs can be significantly altered and the Higgs can be as light as 86 GeV. Discovering the Higgs boson in these models is challenging when the pseudoscalar is lighter than 10 GeV because it decays dominantly into tau leptons. In this paper, we discuss discovering the Higgs in a subdominant decay mode where one of the pseudoscalars decays t… more
Date: June 19, 2009
Creator: Lisanti, Mariangela; Wacker, Jay G. & /SLAC /Stanford U., Phys. Dept.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Search for Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT

Description: Large extra dimensions (LED) have been proposed to account for the apparent weakness of gravitation. These theories also indicate that the postulated massive Kaluza-Klein (KK) gravitons may be produced by nucleon-nucleon bremsstrahlung in the course of core collapse of supernovae. Hannestad and Raffelt have predicted energy spectra of gamma ray emission from the decay of KK gravitons trapped by the gravity of the remnant neutron stars (NS). These and other authors have used EGRET data on NS to … more
Date: September 19, 2012
Creator: Berenji, Bijan & /Stanford U., Appl. Phys. Dept. /SLAC
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Construction and Bench Testing of a Rotatable Collimator for the LHC Collimation Upgrade

Description: The Phase II upgrade to the LHC collimation system calls for complementing the 30 high robust Phase I graphite secondary collimators with 30 high Z Phase II collimators. The Phase II collimators must be robust in various operating conditions and accident scenarios. This paper reports on the final construction and testing of the prototype collimator to be installed in the SPS (Super Proton Synchrotron) at CERN. Bench-top measurements will demonstrate that the device is fully operational and has … more
Date: August 26, 2010
Creator: Smith, Jeffrey Claiborne; Keller, Lewis; Lundgren, Steven; Markiewicz, Thomas & /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Novel QCD Phenomenology

Description: I review a number of topics where conventional wisdom in hadron physics has been challenged. For example, hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation. Such 'direct' processes can explain the deviations from perturbative QCD predictions in measurements of inclusive hadron cross sections at fixed x{sub T} = 2p{sub T}/{radical}s, as well as the 'baryon anomaly', the anomalously large proton-to-pion rati… more
Date: August 12, 2011
Creator: Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of B -> omega lv Decays with BaBar (SULI)

Description: As part of the BaBar project at SLAC to study the properties of B mesons, we have carried out a study of the exclusive charmless semileptonic decay mode B {yields} wlv, which can be used to determine the Cabbibo-Kobayashi-Maskawa matrix element V{sub ub}. Using simulated event samples, this study focuses on determining criteria on variables for selection of B {yields} wlv signal and suppression of background from other types of B{bar B} events and continuum processes. In addition, we determine … more
Date: December 15, 2005
Creator: Chu, Yi-Wen; /MIT; Littlejohn, B.; /Unlisted; Dingfelder, J. & /SLAC
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FERMI view of the TeV blazar Markarian 421

Description: The high energy component of the TeV blazar Markarian 421 has been extensively studied since the beginning of the 90s, when the source was first detected at gamma-rays with EGRET and the Whipple Telescope, yet the source is still far from being understood. The high sensitivity, large dynamic range, and excellent time coverage of the Fermi Large Area Telescope (LAT), all representing significant advances over previous gamma-ray observations, will play a key role in the elucidation of the physica… more
Date: August 26, 2010
Creator: Paneque, D; /SLAC /KIPAC, Menlo Park; Raino, S.; /Bari Polytechnic /INFN, Bari; Chiang, J.; /SLAC /KIPAC, Menlo Park et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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