26 research outputs found
Recommended from our members
Direct measurements of beta-star in the Tevatron
Simultaneous turn-by-turn beam position measurements across collider detector long straight sections provide full phase space information of a free oscillation. For signals with enough coherence (typically 1-2000 revolutions) the amplitude function and its slope at the two BPM's can be directly measured. Results for the Tevatron low-{beta} regions with a few percent accuracy are described
Operation Of The NuMi Beam Monitoring System
The NuMI (Neutrinos at the Main Injector) facility produces an intense neutrino beam for experiments. The NuMI Beam Monitoring system consists of four arrays of ion chambers that measure the intensity and distribution of the remnant hadron and tertiary muon beams produced in association with the neutrinos. The ion chambers operate in an environment of high particle fluxes and high radiation.Physic
Recommended from our members
SDSS spectroscopic survey of stars
In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. They discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. They show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, they find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Z{sub {circle_dot}}] {approx} -1.3. The median metallicity for the low-metallicity [Z/Z{sub {circle_dot}}] < =1.3 subsample is nearly independent of Galactic cylindrical coordinates R and z, while it decreases with z for the high-metallicity [Z/Z{sub {circle_dot}}] > -1.3 sample. they also find that the low-metallicity sample has {approx} 2.5 times larger velocity dispersion and that it does not rotate (at the {approx} 10 km/s level), while the rotational velocity of the high-metallicity sample decreases smoothly with the height above the galactic plane
Recommended from our members
The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias
The greatest challenge in the interpretation of galaxy clustering data from any surveys is galaxy bias. Using a simple Fisher matrix analysis, we show that the bispectrum provides an excellent determination of linear and non-linear bias parameters of intermediate and high-z galaxies, when all measurable triangle configurations down to mildly non-linear scales, where perturbation theory is still valid, are included. The bispectrum is also a powerful probe of primordial non-Gaussianity. The planned galaxy surveys at z {approx}> 2 should yield constraints on non-Gaussian parameters, f{sub NL}{sup loc.} and f{sub NL}{sup eq.}, that are comparable to, or even better than, those from CMB experiments. We study how these constraints improve with volume, redshift range, as well as the number density of galaxies. Finally we show that a halo occupation distribution may be used to improve these constraints further by lifting degeneracies between gravity, bias, and primordial non-Gaussianity
Recommended from our members
Nonlinear dynamics studies in the Fermilab Tevatron using an ac dipole
Abstract Not Provide
Recommended from our members
Model Calibration and Optics Correction Using Orbit Response Matrix in the Fermilab Booster
We have calibrated the lattice model and measured the beta and dispersion functions in Fermilab's fast-ramping Booster synchrotron using the Linear Optics from Closed Orbit (LOCO) method. We used the calibrated model to implement ramped coupling, dispersion, and beta-beating corrections throughout the acceleration cycle, reducing horizontal beta beating from its initial magnitude of {approx}30% to {approx}10%, and essentially eliminating vertical beta-beating and transverse coupling
Recommended from our members
The CDMS II data acquisition system
The Data Acquisition System for the CDMS II dark matter experiment was designed and built when the experiment moved to its new underground installation at the Soudan Lab. The combination of remote operation and increased data load necessitated a completely new design. Elements of the original LabView system remained as stand-alone diagnostic programs, but the main data processing moved to a VME-based system with custom electronics for signal conditioning, trigger formation and buffering. The data rate was increased 100-fold and the automated cryogenic system was linked to the data acquisition. A modular server framework with associated user interfaces was implemented in Java to allow control and monitoring of the entire experiment remotely
Recommended from our members
Search for New Bottomlike Quark Pair Decays Q Q-Bar to (T W- ) (T-Bar W -) in Same-Charge Dilepton Events
We report the most restrictive direct limits on masses of fourth-generation down-type quarks b{prime}, and quark-like composite fermions (B or T{sub 5/3}), decaying promptly to tW{sup {-+}}. We search for a significant excess of events with two same-charge leptons (e, {mu}), several hadronic jets, and missing transverse energy. An analysis of data from p{bar p} collisions with an integrated luminosity of 2.7 fb{sup -1} collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits m{sub b{prime}}, m{sub B} > 338 GeV/c{sup 2} and m{sub T{sub 5/3}} > 365 GeV/c{sup 2} at 95% confidence level