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in subjects: "Fermilab Accelerator"

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Improved Limits on $B^{0}$ Decays to Invisible $(+gamma)$ Final States

We establish improved upper limits on branching fractions for B{sup 0} decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 million B{ba… more

Date: November 1, 2013

Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET

FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of… more

Date: September 14, 2012

Creator: Clarke, C. I.; Adli, E.; Corde, S.; Decker, F. J.; England, R. J.; Erickson, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Longitudinal Bunch Pattern Measurements through Single Photon Counting at SPEAR3

The Stanford Synchrotron Radiation Lightsource (SSRL), a division of SLAC National Accelerator Laboratory, is a synchrotron light source that provides x-rays for experimental use. As electrons are bent in the storage ring, they emit electromagnetic radiation. There are 372 different buckets which electrons can be loaded into. Different filling patterns produce different types of x-rays. What is the bunch pattern at a given time? Which filling pattern is better? Are there any flaws to the curren… more

Date: September 7, 2012

Creator: Wang, Hongyi (Jack) & /UC, San Diego

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Optical Design of a Broadband Infrared Spectrometer for Bunch Length Measurement at the Linac Coherent Light Source

The electron pulses generated by the Linac Coherent Light Source at the SLAC National Accelerator Laboratory occur on the order of tens of femtoseconds and cannot be directly measured by conventional means. The length of the pulses can instead be reconstructed by measuring the spectrum of optical transition radiation emitted by the electrons as they move toward a conducting foil. Because the emitted radiation occurs in the mid-infrared from 0.6 to 30 microns a novel optical layout is required. … more

Date: September 7, 2012

Creator: Williams, Kiel

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Measurement of the Time-Dependent CP Asymmetry of Partially Reconstructed B0 to D+D- Decays

We present a new measurement of the time-dependent CP asymmetry of B{sup 0} {yields}D*{sup +}D*{sup -} decays using (471 {+-} 5) million B{bar B} pairs collected with the BABAR detector at the PEP-II B Factory at the SLAC National Accelerator Laboratory. Using the technique of partial reconstruction, we measure the time-dependent CP asymmetry parameters S = -0.34 {+-} 0.12 {+-} 0.05 and C = +0:15 {+-} 0.09 {+-} 0.04. Using the value for the CP-odd fraction R{perpendicular} = 0.158 {+-} 0.028 {+… more

Date: August 13, 2012

Creator: Lees, J. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LCLS-II New Instruments Workshops Report

The LCLS-II New Instruments workshops chaired by Phil Heimann and Jerry Hastings were held on March 19-22, 2012 at the SLAC National Accelerator Laboratory. The goal of the workshops was to identify the most exciting science and corresponding parameters which will help define the LCLS-II instrumentation. This report gives a synopsis of the proposed investigations and an account of the workshop. Scientists from around the world have provided short descriptions of the scientific opportunities the… more

Date: August 8, 2012

Creator: Baradaran, Samira; Bergmann, Uwe; Durr, Herrmann; Gaffney, Kelley; Goldstein, Julia; Guehr, Markus et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

FACET Tolerances for Static and Dynamic Misalignments

The Facility for AdvancedAccelerator and Experimental Tests (FACET) at the SLAC National Accelerator Laboratory is designed to deliver a beam with a transverse spot size on the order of 10 {micro}m x 10 {micro}m in a new beamline constructed at the two kilometer point of the SLAC linac. Commissioning the beamline requires mitigating alignment errors and their effects, which can be significant and result in spot sizes orders of magnitude larger. Sextupole and quadrupole alignment errors in parti… more

Date: July 13, 2012

Creator: Federico, Joel

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW… more

Date: July 3, 2012

Creator: Chu, Tak Sum; Anderson, Scott; Barty, Christopher; Gibson, David; Hartemann, Fred; Marsh, Roark et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Echo-Enabled Harmonic Generation

A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demo… more

Date: June 28, 2012

Creator: Stupakov, Gennady

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fermi Large Area Telescope Operations: Progress Over 4 Years

The Fermi Gamma-ray Space Telescope was launched into orbit in June 2008, and is conducting a multi-year gamma-ray all-sky survey, using the main instrument on Fermi, the Large Area Telescope (LAT). Fermi began its science mission in August 2008, and has now been operating for almost 4 years. The SLAC National Accelerator Laboratory hosts the LAT Instrument Science Operations Center (ISOC), which supports the operation of the LAT in conjunction with the Mission Operations Center (MOC) and the F… more

Date: June 28, 2012

Creator: Cameron, Robert A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The History of X-ray Free-Electron Lasers

The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provide… more

Date: June 28, 2012

Creator: Pellegrini, C. & /SLAC, /UCLA

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons

We present improved measurements of CP-violation parameters in the decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} K{sup +}{pi}{sup -}, and B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and of the branching fractions for B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0} and B{sup 0} {yields} K{sup 0}{pi}{sup 0}. The results are obtained with the full data set collected at the {Upsilon}(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy B factory at the SLAC National Acc… more

Date: June 18, 2012

Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LCLS-II Undulator Tolerance Analysis

The SLAC National Accelerator Laboratory is building a new FEL user facility, LCLS-II, as a major upgrade to the Linear Coherent Light Source (LCLS). The upgrade will include two new Free Electron Lasers (FELs), to generate soft (SXR) and hard x-ray (HXR) SASE FEL radiation, based on planar, variable gap hybrid undulators with two different undulator periods (SXU: 55 mm, HXU: 32 mm). An algebraic FEL tolerance analysis for the undulator lines, including tuning, alignment, and phase correction t… more

Date: June 6, 2012

Creator: Nuhn, H. D.; Marks, S. & Wu, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Search for Lepton-Number Violating Processes in B+ to h- l+ l+ Decays

We have searched for the lepton-number violating processes B{sup +} {yields} h{sup -}{ell}{sup +}{ell}{sup +} with h{sup -} = K{sup -}/{pi}{sup -} and {ell}{sup +} = e{sup +}/{mu}{sup +}, using a sample of 471 {+-} 3 million B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. We find no evidence for these decays and place 90% confidence level upper limits on their branching fractions B (B{sup +} {yields} {pi}{sup… more

Date: May 17, 2012

Creator: Lees, J.P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

FACET: SLAC’s New User Facility

FACET (Facility for Advanced Accelerator Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. The first User Run started in spring 2012 with 20 GeV, 3 nC electron beams. The facility is designed to provide short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. The creation of driv… more

Date: May 16, 2012

Creator: Clarke, C. I.; Decker, F. -J.; England, R. J.; Erickson, R. A.; Hast, C.; Hogan, M. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

GLADE Global Liquid Argon Detector Experiment: a letter of intent to FNAL

The recent measurements of the {theta}{sub 13} mixing angle, which controls the observable size of any CP violation effects, open a window of opportunity to take advantage of the world's most powerful existing neutrino beam together with recent successes in development of the ultimate detector technology for the detection of electron neutrinos : a liquid argon (LAr) time projection chamber. During this proposed project a 5kt LAr detector (GLADE) will be developed by European groups to be put in… more

Date: May 13, 2012

Creator: Thomas, Jennifer

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Project X RFQ EM Design

Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H- ion source, a low-energy beam transport (LEBT), a CW 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of th… more

Date: May 9, 2012

Creator: Romanov, Gennady; Hoff, Matthew; Li, Derun; Staples, John & Virostek, Steve

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Lepton Universality Test in Upsilon(1S) Decays at BaBar

Using a sample of 122 million {Upsilon}(3S) decays collected with the BABAR detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio R{sub {tau}{mu}} = BR({Upsilon}(1S) {yields} {tau}{sup +}{tau}{sup -})/BR({Upsilon}(1S) {yields} {mu}{sup +}{mu}{sup -}); the measurement is intended as a test of lepton universality and as a possible search for a light pseudoscalar Higgs boson in Next to Minimal Supersymmetric Standard Model (NMSSM) scena… more

Date: April 10, 2012

Creator: Guido, Elisa & /Genoa U. /INFN, Genoa

Item Type: Article

Partner: UNT Libraries Government Documents Department

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… more

Date: April 6, 2012

Creator: Paramesvaran, S. & /Royal Holloway, U. of London

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Search for a Low-Mass Higgs Boson (A0) at BaBar

The BABAR Collaboration has performed three searches for a light Higgs boson, A{sup 0}, in radiative Upsilon ({Upsilon}) decays: {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {tau}{sup +}{tau}{sup -}; {Upsilon}(nS) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -} (n = 2,3); and {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} invisible. Such a Higgs boson (A{sup 0}) appears in the Next-to-Minimal Supersymmetric extensions of the Standard Model, where a lig… more

Date: April 5, 2012

Creator: Mokhtar, Arafat Gabareen

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Two- and Three-Body Charmless B Decays at BaBar

We report recent measurements of rare charmless B decays performed by BaBar. The results are based on the final BaBar dataset of 424 fb{sup -1} collected at the PEP-II B-factory based at the SLAC National Accelerator Laboratory. The study of rare B decays is a key ingredient to meet two of the main goals of the B-factories: assessing the validity of the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP-violation by precisely measuring the elements of the Unitarity Triangle (UT), and searching for h… more

Date: April 5, 2012

Creator: Stracka, Simone

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of CP violation in Dalitz-plot analyses of B0 to K K-KS, B to K K-K , and B to KSKSK

We perform amplitude analyses of the decays B{sup 0} {yields} K{sup +}K{sup -}K{sub s}{sup 0}, B{sup +} {yields} K{sup +}K{sup -}K{sup +}, and B{sup +} {yields}, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470 x 10{sup 6} B{bar B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B{sup +} {yields} K{sup +}K{sup -}K{sup +}, we find a … more

Date: March 20, 2012

Creator: Lees, J.P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Facts About XLDB-2011

This note provides details of the 5th Extremely Large Databases Conference and Invitational Workshop that were held in 2011 on 18-19 October and 20 October, respectively, at the SLAC National Accelerator Laboratory in Menlo Park, California. The main goals of the conference were: (1) Encourage and accelerate the exchange of ideas between users trying to build extremely large databases worldwide and database solution providers; (2) Share lessons, trends, innovations, and challenges related to bu… more

Date: February 22, 2012

Creator: Becla, Jacek; Lim, Kian-Tat & Wang, Daniel L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of charmonium resonances in the gg -> K0SK pi- and gg -> K K-pi pi-pi0 processes

This thesis reports the analysis of the e{sup +}e{sup -} {yields} e{sup +}e{sup -}K{sub S}{sup 0}K{sup {+-}}{pi}{sup {-+}} and e{sup +}e{sup -} {yields} e{sup +}e{sup -}K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup 0} processes using the final dataset of the BABAR experiment located at the SLAC National Accelerator Laboratory. From previous measurements, the K{sub S}{sup 0}K{sup {+-}}{pi}{sup {-+}} final state is known to show a clear signal from the {eta}{sub c}(2S) particle. This c{bar c} st… more

Date: February 22, 2012

Creator: Biassoni, Pietro & /U. Milan, Dept. Phys.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department