27 research outputs found

    Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

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    We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62 million iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class

    The Alpha Magnetic Spectrometer (AMS) on the international space station: Part II — Results from the first seven years

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    The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting a unique, long-duration mission of fundamental physics research in space. The physics objectives include the precise studies of the origin of dark matter, antimatter, and cosmic rays as well as the exploration of new phenomena. Following a 16-year period of construction and testing, and a precursor flight on the Space Shuttle, AMS was installed on the ISS on May 19, 2011. In this report we present results based on 120 billion charged cosmic ray events up to multi-TeV energies. This includes the fluxes of positrons, electrons, antiprotons, protons, and nuclei. These results provide unexpected information, which cannot be explained by the current theoretical models. The accuracy and characteristics of the data, simultaneously from many different types of cosmic rays, provide unique input to the understanding of origins, acceleration, and propagation of cosmic rays

    Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station

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    Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law RΔ with index Δ = −0.333 +/- 0.014(fit) +/- 0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ = −1/3 asymptotically.</p

    Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

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    International audienceWe present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of 1×1091 \times 10^9 events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. We observed that, below 40 GV, the proton flux and the helium flux show nearly identical fine structures in both time and relative amplitude. The amplitudes of the flux structures decrease with increasing rigidity and vanish above 40 GV. The amplitudes of the structures are reduced during the time period, which started one year after solar maximum, when the proton and helium fluxes steadily increase. Above ∼3\sim 3  GV the p/He flux ratio is time independent. We observed that below ∼3\sim 3  GV the ratio has a long-term decrease coinciding with the period during which the fluxes start to rise

    First Run 2 Searches for Exotica at CMS

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    An overview of the first results of the experimental searches for exotica at the CMS experiment with 13 TeV collision data is presented. The results cover various models with different topologies such as searches for new heavy resonances, extra space dimensions, black holes and dark matter. The analysis results with 13 TeV data are emphasized, corresponding to an integrated luminosity in the range of 2.1–2.8 f

    First run 2 searches for exotica at CMS

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    An overview of the first results of the experimental searches for exotica at the CMS experiment with 13 TeV collision data is presented. The results cover various models with different topologies such as searches for new heavy resonances, extra space dimensions, black holes and dark matter. The analysis results with 13 TeV data are emphasized, corresponding to an integrated luminosity in the range of 2.1-2.8 fb-1, and the results are presented in comparison to those obtained with 8 TeV data

    Verkkokaupan konversioasteen kasvattaminen : case Nut Express

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    Case: Nut Express verkkokaupan konversion parantaminen keskittymällä loppukäyttäjän ostokokemuksen parantamiseen sekä helpottamiseen ostoprosessin aikana. Tehtävänä on laatia Nut Express:lle ohjeistus tarvittaviin muutoksiin verkkokaupassa käyttöliittymän parantamiseksi ja tätä kautta konversioasteen nostamiseksi. Tavoitteena on parantaa loppukäyttäjän ostokokemusta verkkokaupassa sekä kannustaa asiakasta ostopäätöksen tekemiseen. Tutkimusmenetelmäksi muodostui uusi, ostoprosessia videolla kuvaava menetelmä. Nimitämme tätä konversiokaareksi. Konversiokaari koostuu Nut Expressin osalta neljästä päätoimesta, joiden todettiin olevan mediaani toimintatapa verkkokaupassa asioivilla asiakkailla. Lisäksi teetimme kyselyn verkossa tapahtuvaan asiakaspalveluun ja ostokäyttäytymiseen liittyen. Kyselyyn vastasi 336 verkkokauppoja käyttävää suomalaista. Lopputuloksena syntyi kattava kehitysehdotuskokonaisuuden Nut Expressin verkkokaupalle. Olemme listanneet jokaisen konversiokaaren osalta selkeät muutokset, jotka on hyvä tehdä mahdollisimman nopeasti ja A/B-testaukseen suositeltavat kehityskohteet

    The Alpha Magnetic Spectrometer (AMS) on the international space station: Part II — Results from the first seven years

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    The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting a unique, long-duration mission of fundamental physics research in space. The physics objectives include the precise studies of the origin of dark matter, antimatter, and cosmic rays as well as the exploration of new phenomena. Following a 16-year period of construction and testing, and a precursor flight on the Space Shuttle, AMS was installed on the ISS on May 19, 2011. In this report we present results based on 120 billion charged cosmic ray events up to multi-TeV energies. This includes the fluxes of positrons, electrons, antiprotons, protons, and nuclei. These results provide unexpected information, which cannot be explained by the current theoretical models. The accuracy and characteristics of the data, simultaneously from many different types of cosmic rays, provide unique input to the understanding of origins, acceleration, and propagation of cosmic rays
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