3,466 research outputs found

    LHCb Upgrade Plans

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    The LHCb experiment will operate for about five years at a luminosity of 2x10^32 cm^-2 s^-1 and plans are to accumulate a data sample of ~10 fb^-1. Here we present the physics programme and detector design for a future high luminosity phase of the LHCb experiment. An upgraded LHCb experiment would operate at ten times the design luminosity, i.e. at ~2x10^33 cm^-2 s^-1 and aims to collect a data sample of ~100 fb^-1 over five years. This programme would allow the probe of new physics at an unprecedented level. Key measurements include the B^0_s mixing phase phi_s in B^0_s -> J/\psi phi and B^0_s -> phi phi decays with a significant sensitivity to the small Standard Model prediction and a very precise measurement of the CKM angle gamma in tree diagram decays. Initial studies of the modified LHCb trigger and detectors are presented. The upgraded LHCb experiment can run with or without an LHC luminosity upgrade.Comment: 6 pages, 2 figures, to appear in the proceedings of International Conference on B-Physics at Hadron Machines (Beauty 2006), Oxford, England, 25-29 Sep 200

    Storage and retrieval of vector beams of light in a multiple-degree-of-freedom quantum memory

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    The full structuration of light in the transverse plane, including intensity, phase and polarization, holds the promise of unprecedented capabilities for applications in classical optics as well as in quantum optics and information sciences. Harnessing special topologies can lead to enhanced focusing, data multiplexing or advanced sensing and metrology. Here we experimentally demonstrate the storage of such spatio-polarization-patterned beams into an optical memory. A set of vectorial vortex modes is generated via liquid crystal cell with topological charge in the optic axis distribution, and preservation of the phase and polarization singularities is demonstrated after retrieval, at the single-photon level. The realized multiple-degree-of-freedom memory can find applications in classical data processing but also in quantum network scenarios where structured states have been shown to provide promising attributes, such as rotational invariance

    Device-independent certification of high-dimensional quantum systems

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    An important problem in quantum information processing is the certification of the dimension of quantum systems without making assumptions about the devices used to prepare and measure them, that is, in a device-independent manner. A crucial question is whether such certification is experimentally feasible for high-dimensional quantum systems. Here we experimentally witness in a device-independent manner the generation of six-dimensional quantum systems encoded in the orbital angular momentum of single photons and show that the same method can be scaled, at least, up to dimension 13.Comment: REVTeX4, 5 pages, 2 figure

    A search for Z' in muon neutrino associated charm production

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    In many extensions of the Standard Model the presence of an extra neutral boson, Z', is invoked. A precision study of weak neutral-current exchange processes involving only second generation fermions is still missing. We propose a search for Z' in muon neutrino associated charm production. This process only involves Z' couplings with fermions from the second generation. An experimental method is thoroughly described using an ideal detector. As an application, the accuracy reachable with present and future experiments has been estimated.Comment: 13 pages, 3 figures, late

    Improved magnetic charged system search optimization algorithm with application to satellite formation flying

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    This paper is devoted to the implementation and application of an improved version of the metaheuristic algorithm called magnetic charged system search. Some modifications and novelties are introduced and tested. Firstly, the authors’ attempt is to develop a self-adaptive and user-friendly algorithm which can automatically set all the preliminary parameters (such as the numbers of particles, the maximum iterations number) and the internal coefficients. Indeed, some mathematical laws are proposed to set the parameters and many coefficients can dynamically change during the optimization process based on the verification of internal conditions. Secondly, some strategies are suggested to enhance the performances of the proposed algorithm. A chaotic local search is introduced to improve the global best particle of each iteration by exploiting the features of ergodicity and randomness. Moreover, a novel technique is proposed to handle bad-defined boundaries; in fact, the possibility to self-enlarge the boundaries of the optimization variables is considered, allowing to achieve the global optimum even if it is located on the boundaries or outside. The algorithm is tested through some benchmark functions and engineering design problems, showing good results, followed by an application regarding the problem of time-suboptimal manoeuvres for satellite formation flying, where the inverse dynamics technique, together with the B-splines, is employed. This analysis proves the ability of the proposed algorithm to optimize control problems related to space engineering, obtaining better results with respect to more common and used algorithms in literature

    Can Twitter be a source of information on allergy? Correlation of pollen counts with tweets reporting symptoms of allergic rhinoconjunctivitis and names of antihistamine drugs

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    Pollen forecasts are in use everywhere to inform therapeutic decisions for patients with allergic rhinoconjunctivitis (ARC). We exploited data derived from Twitter in order to identify tweets reporting a combination of symptoms consistent with a case definition of ARC and those reporting the name of an antihistamine drug. In order to increase the sensitivity of the system, we applied an algorithm aimed at automatically identifying jargon expressions related to medical terms. We compared weekly Twitter trends with National Allergy Bureau weekly pollen counts derived from US stations, and found a high correlation of the sum of the total pollen counts from each stations with tweets reporting ARC symptoms (Pearson's correlation coefficient: 0.95) and with tweets reporting antihistamine drug names (Pearson's correlation coefficient: 0.93). Longitude and latitude of the pollen stations affected the strength of the correlation. Twitter and other social networks may play a role in allergic disease surveillance and in signaling drug consumptions trends
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