2,610 research outputs found

    Optimal Time Advance In Terminal Area Arrivals: Throughput vs. Fuel Savings

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    The current operational practice in scheduling air traffic arriving at an airport is to adjust flight schedules by delay, i.e. a postponement of an aircrafts arrival at a scheduled location, to manage safely the FAA-mandated separation constraints between aircraft. To meet the observed and forecast growth in traffic demand, however, the practice of time advance (speeding up an aircraft toward a scheduled location) is envisioned for future operations as a practice additional to delay. Time advance has two potential advantages. The first is the capability to minimize, or at least reduce, the excess separation (the distances between pairs of aircraft immediately in-trail) and thereby to increase the throughput of the arriving traffic. The second is to reduce the total traffic delay when the traffic sample is below saturation density. A cost associated with time advance is the fuel expenditure required by an aircraft to speed up. We present an optimal control model of air traffic arriving in a terminal area and solve it using the Pontryagin Maximum Principle. The admissible controls allow time advance, as well as delay, some of the way. The cost function reflects the trade-off between minimizing two competing objectives: excess separation (negatively correlated with throughput) and fuel burn. A number of instances are solved using three different methods, to demonstrate consistency of solutions

    Measurement of the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay form factors in the OKA experiment

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    A precise measurement of the vector and axial-vector form factors difference FVFAF_V-F_A in the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay is presented. About 95K events of K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} are selected in the OKA experiment. The result is FVFA=0.134±0.021(stat)±0.027(syst)F_V-F_A=0.134\pm0.021(stat)\pm0.027(syst). Both errors are smaller than in the previous FVFAF_V-F_A measurements.Comment: 9 pages, 8 figure

    Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment

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    We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta < 7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations for the response of the CASTOR calorimeter, and in particular to the traversal of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR

    Test of an LED Monitoring System for the PHOS Spectrometer

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    Preprint submitted to Elsevier Print on 26th January 2000A prototype monitoring system for the Photon Spectrometer (PHOS) of the ALICE experiment at LHC is described in detail. The prototype consists of Control and Master modules. The first one is 8x8 matrix of Light Emitting Diodes coupled with stable generators of current pulses. The system provides an individual control for each of the 64 channels of PHOS prototype based on lead-tungstate crystals. A long term stability of order of 10-3 has been achieved in integral beam tests of the monitoring system and PHOS prototypes

    The Physics of Ultraperipheral Collisions at the LHC

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    We discuss the physics of large impact parameter interactions at the LHC: ultraperipheral collisions (UPCs). The dominant processes in UPCs are photon-nucleon (nucleus) interactions. The current LHC detector configurations can explore small xx hard phenomena with nuclei and nucleons at photon-nucleon center-of-mass energies above 1 TeV, extending the xx range of HERA by a factor of ten. In particular, it will be possible to probe diffractive and inclusive parton densities in nuclei using several processes. The interaction of small dipoles with protons and nuclei can be investigated in elastic and quasi-elastic J/ψJ/\psi and Υ\Upsilon production as well as in high tt ρ0\rho^0 production accompanied by a rapidity gap. Several of these phenomena provide clean signatures of the onset of the new high gluon density QCD regime. The LHC is in the kinematic range where nonlinear effects are several times larger than at HERA. Two-photon processes in UPCs are also studied. In addition, while UPCs play a role in limiting the maximum beam luminosity, they can also be used a luminosity monitor by measuring mutual electromagnetic dissociation of the beam nuclei. We also review similar studies at HERA and RHIC as well as describe the potential use of the LHC detectors for UPC measurements.Comment: 229 Pages, 121 figure

    Model of Centauro and strangelet production in heavy ion collisions

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    We discuss the phenomenological model of Centauro event production in relativistic nucleus-nucleus collisions. This model makes quantitative predictions for kinematic observables, baryon number and mass of the Centauro fireball and its decay products. Centauros decay mainly to nucleons, strange hyperons and possibly strangelets. Simulations of Centauro events for the CASTOR detector in Pb-Pb collisions at LHC energies are performed. The signatures of these events are discussed in detail.Comment: 19 pages, LaTeX+revtex4, 14 eps-figures and 3 table

    Searches for the light invisible axion-like particle in K+π+π0aK^{+}\to\pi^{+}\pi^{0}a decay

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    A high statistics data sample of the K+K^{+} decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) aa in the decay K+π+π0aK^{+} \to \pi^{+} \pi^{0} a. No signal is observed, the upper limits for the branching ratio of the decay are calculated. The 90%90\% confidence level upper limit is changing from 2.51062.5\cdot10^{-6} to 21072\cdot10^{-7} for the ALP mass from 0 to 200 MeV/c2c^{2}, except for the region of π0\pi^{0} mass, where the upper limit is 4.41064.4\cdot10^{-6}.Comment: 6 pages, 6 figure

    Observation of K+π+π0π0γK^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma decay

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    The K+π+π0π0γK^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma decay is observed by the OKA collaboration. The branching ratio is measured to be (4.1±0.9(stat)±0.4(syst))×106(4.1 \pm 0.9(stat) \pm 0.4(syst))\times 10^{-6}. The branching ratio and γ\gamma energy spectrum are consistent with ChPT prediction.Comment: arXiv admin note: text overlap with arXiv:2310.1642
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