2,601 research outputs found
Ballistic Coalescence Model
We study statistical properties of a one dimensional infinite system of
coalescing particles. Each particle moves with constant velocity
towards its closest neighbor and merges with it upon collision. We propose a
mean-field theory that confirms a concentration decay obtained in
simulations and provides qualitative description for the densities of growing,
constant, and shrinking inter-particle gaps.Comment: 4 pages, 2 column Revtex, 5 figures include
Luminosity Optimization and Calibration in the LHC
The ability of a particle collider to produce the required number of events, the luminosity, is usually used to size its performances. As demonstrated in many accelerators optimizing and calibrating the luminosity can be done using the Van Der Meer method which consist of shifting one beam with respect to the other while recording the event rate. In the LHC it is planned to perform those scans at the four interaction points using the data from the machine detectors as well as the ones from the experiments. A graphical user interface (GUI) has been developed for this purpose. We looked into procedures to quantify and if possible minimize the systematic errors coming from the measurements and the beam parameters and will discuss how we plan on using the relevant informations such as the vertex position or background measurements coming from the experiments
Recent progress on isospin breaking corrections and their impact on the muon g-2 value
We describe some recent results on isospin breaking corrections which are of
relevance for predictions of the leading order hadronic contribution to the
muon anomalous magnetic moment (amuhadLO) when using tau lepton data. When
these corrections are applied to the new combined data on the pi^+pi^0 spectral
function, the prediction for amuhadLO based on tau lepton data gets closer to
the one obtained using e^+e^- data.Comment: 6 pages, 3 figures, Proceedings of the PhiPsi09 Workshop, Oct. 13-16,
2009, Beijing, China. Some typos corrected, and the FSR correction used in a
previous work is added to Table
Decline and Fall of the Standard Model?
Motivations for physics beyond the Standard Model are reviewed, with
particular emphasis on supersymmetry at the TeV scale. Constraints on the
minimal supersymmetric extension of the Standard Model with universal soft
supersymmetry-breaking terms (CMSSM) are discussed. These are also combined
with the supersymmetric interpretation of the anomalous magnetic moment of the
muon. The prospects for observing supersymmetry at accelerators are reviewed
using benchmark scenarios to focus the discussion. Prospects for other
experiments are discussed, including the detection of cold dark matter, mu -> e
gamma and related processes, as well as proton decay.Comment: Invited talk at 20th International Symposium on Lepton and Photon
Interactions at High Energies, Rome, 2001, 16 pages LaTeX, 13 eps figures,
uses special .cls file (included
A decision support tool for the order promising process with product homogeneity requirements in hybrid Make-To-Stock and Make-To-Order environments. Application to a ceramic tile company
[EN] Order promising in manufacturing systems that produce non-uniform units of the same finished good becomes a more complex process when customer orders need to be served with homogeneous units. To facilitate this task, we propose a mathematical model-based decision tool to support the order promising process according to product homogeneity requirements in hybrid Make-To-Stock (MTS) and Make-To-Order (MTO) contexts. In these manufacturing environments, the comparison of Available-To-Promise (ATP) and/or Capable-To-Promise (CTP) quantities with homogeneous ones ordered by customers is necessary during the order commitment. To properly deal with customers' product uniformity requirements, different ATP consumption rules are implemented by defining a novel objective function. CTP modelling in these systems also entails having to address new aspects, such as estimating future homogeneous quantities in additional lots to the master plan, accomplishing minimum lot sizes and saving in setups when programming new lots. By including CTP in the order promising model, a closer integration with the master production schedule is achieved. The resulting mathematical model was applied to a ceramic tile company in different supply scenarios and execution modes, and at several availability levels (ATP and ATP&CTP). The results validate model performance and provide insights into the impact of ATP consumption rules on the profits made from committed customer orders in different scenarios for the specific ceramic tile company.This work was supported by the Spanish Ministry of Economy and Competitiveness with Grant DPI2011-23597 and the Universitat Polito cnica de Valencia with Grant Ref. PAID-06-11/1840.Alemany Díaz, MDM.; Ortiz Bas, Á.; Fuertes-Miquel, VS. (2018). A decision support tool for the order promising process with product homogeneity requirements in hybrid Make-To-Stock and Make-To-Order environments. Application to a ceramic tile company. Computers & Industrial Engineering. 122:219-234. https://doi.org/10.1016/j.cie.2018.05.040S21923412
Rates of convergence of nonextensive statistical distributions to Levy distributions in full and half spaces
The Levy-type distributions are derived using the principle of maximum
Tsallis nonextensive entropy both in the full and half spaces. The rates of
convergence to the exact Levy stable distributions are determined by taking the
N-fold convolutions of these distributions. The marked difference between the
problems in the full and half spaces is elucidated analytically. It is found
that the rates of convergence depend on the ranges of the Levy indices. An
important result emerging from the present analysis is deduced if interpreted
in terms of random walks, implying the dependence of the asymptotic long-time
behaviors of the walks on the ranges of the Levy indices if N is identified
with the total time of the walks.Comment: 20 page
Hadronic Vacuum Polarization and the Lamb Shift
Recent improvements in the determination of the running of the fine-structure
constant also allow an update of the hadronic vacuum-polarization contribution
to the Lamb shift. We find a shift of -3.40(7) kHz to the 1S level of hydrogen.
We also comment on the contribution of this effect to the determination by
elastic electron scattering of the r.m.s. radii of nuclei.Comment: 7 pages, latex, 1 figure -- Submitted to Phys. Rev. A -- epsfig.sty
require
Hadron Production via e+e- Collisions with Initial State Radiation
A novel method of studying e+e- annihilation into hadrons using initial state
radiation at e+e- colliders is described. After brief history of the method,
its theoretical foundations are considered. Numerous experiments in which
exclusive cross sections of e+e- annihilation into hadrons below the
center-of-mass energy of 5 GeV have been measured are presented. Some
applications of the results obtained to fundamental tests of the Standard Model
are listed.Comment: 50 pages, 88 figures, accepted for publication in Rev. Mod. Phy
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