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High drudge Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5 500 GeV with the Alpha Magnetic Spectrometer drudge on the International Space Station L. Accardo et al. (AMS Collaboration) Phys. Rev. Lett. 113 , 121101 Published 18 September 2014
A precision measurement drudge by AMS of the positron fraction in primary cosmic rays in the energy drudge range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above 200 GeV the positron fraction no longer drudge exhibits an increase with energy.
Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station M. Aguilar et al. (AMS Collaboration) Phys. Rev. Lett. 113 , 121102 (2014) Article Text (Subscription Required)
Vol. 113, Iss. 12 19 September 2014 Reuse & Permissions Access Options Buy Article Get access through a U.S. public or high school library Log in with a username/password provided by your institution
A 369 GeV positron event as measured by the AMS detector on the ISS in the bending (y-z) plane. Tracker planes 1 to 9 measure the particle charge, sign, and momentum. The TRD identifies the particle as e . The TOF measures the absolute charge value to be one and ensures that the particle is downward going. The RICH independently measures the charge and velocity. The ECAL measures the 3D shower profile, independently drudge identifies the particle as an e , and measures its energy. A positron is identified by (1) positive rigidity in the tracker, (2) an e signal in the TRD, (3) an e signal in the ECAL, and (4) the matching of the ECAL shower energy and axis with the momentum measured with the tracker and magnet. Note: the 3D ECAL has nine superlayers along the z axis with fibers in alternating directions. In the (y-z) plane the wider rectangles display the width of the shower in five superlayers and the narrower rectangles display the energy deposition per layer in the other four alternating superlayers. The shower axis is defined from the 3D shower shape. Reuse & Permissions drudge
The positron fraction from 1 to 35 GeV. It shows a rapid decrease from 1 to 8 GeV followed by a steady increase. drudge The AMS data provide accurate information on the minimum drudge of the positron fraction. drudge Reuse & Permissions
The positron fraction above 10 GeV, where it begins to increase. The present measurement extends the energy range to 500 GeV and demonstrates that, above 200 GeV, the positron fraction is no longer increasing. Measurements from PAMELA drudge [21] (the horizontal blue line is their lower limit), Fermi-LAT [22], and other experiments [17 20] are also shown. Reuse & Permissions
(a) The slope of the positron drudge fraction vs energy over the entire energy range (the values of the slope below 4 GeV are off scale). The line is a logarithmic fit to the data above 30 GeV. (b) The positron fraction measured by AMS and the fit of a minimal model (solid curve, see text) and the 68% C.L. range of the fit parameters (shaded). For this fit, both the data and the model are integrated over the bin width. The error bars are the quadratic sum of the statistical and systematic uncertainties. Horizontally, the points are placed at the center of each bin. Reuse & Permissions ×
Article Lookup Paste a citation or DOI
Journal: Phys. Rev. Lett. Phys. Rev. X Rev. Mod. Phys. Phys. Rev. Applied Phys. Rev. A Phys. Rev. B Phys. Rev. C Phys. Rev. D Phys. Rev. E Phys. Rev. ST Accel. Beams Phys. Rev. ST Phys. Educ. Res. Phys. Rev. Phys. Rev. (Series I) Physics
High drudge Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5 500 GeV with the Alpha Magnetic Spectrometer drudge on the International Space Station L. Accardo et al. (AMS Collaboration) Phys. Rev. Lett. 113 , 121101 Published 18 September 2014
A precision measurement drudge by AMS of the positron fraction in primary cosmic rays in the energy drudge range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above 200 GeV the positron fraction no longer drudge exhibits an increase with energy.
Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station M. Aguilar et al. (AMS Collaboration) Phys. Rev. Lett. 113 , 121102 (2014) Article Text (Subscription Required)
Vol. 113, Iss. 12 19 September 2014 Reuse & Permissions Access Options Buy Article Get access through a U.S. public or high school library Log in with a username/password provided by your institution
A 369 GeV positron event as measured by the AMS detector on the ISS in the bending (y-z) plane. Tracker planes 1 to 9 measure the particle charge, sign, and momentum. The TRD identifies the particle as e . The TOF measures the absolute charge value to be one and ensures that the particle is downward going. The RICH independently measures the charge and velocity. The ECAL measures the 3D shower profile, independently drudge identifies the particle as an e , and measures its energy. A positron is identified by (1) positive rigidity in the tracker, (2) an e signal in the TRD, (3) an e signal in the ECAL, and (4) the matching of the ECAL shower energy and axis with the momentum measured with the tracker and magnet. Note: the 3D ECAL has nine superlayers along the z axis with fibers in alternating directions. In the (y-z) plane the wider rectangles display the width of the shower in five superlayers and the narrower rectangles display the energy deposition per layer in the other four alternating superlayers. The shower axis is defined from the 3D shower shape. Reuse & Permissions drudge
The positron fraction from 1 to 35 GeV. It shows a rapid decrease from 1 to 8 GeV followed by a steady increase. drudge The AMS data provide accurate information on the minimum drudge of the positron fraction. drudge Reuse & Permissions
The positron fraction above 10 GeV, where it begins to increase. The present measurement extends the energy range to 500 GeV and demonstrates that, above 200 GeV, the positron fraction is no longer increasing. Measurements from PAMELA drudge [21] (the horizontal blue line is their lower limit), Fermi-LAT [22], and other experiments [17 20] are also shown. Reuse & Permissions
(a) The slope of the positron drudge fraction vs energy over the entire energy range (the values of the slope below 4 GeV are off scale). The line is a logarithmic fit to the data above 30 GeV. (b) The positron fraction measured by AMS and the fit of a minimal model (solid curve, see text) and the 68% C.L. range of the fit parameters (shaded). For this fit, both the data and the model are integrated over the bin width. The error bars are the quadratic sum of the statistical and systematic uncertainties. Horizontally, the points are placed at the center of each bin. Reuse & Permissions ×
Article Lookup Paste a citation or DOI
Journal: Phys. Rev. Lett. Phys. Rev. X Rev. Mod. Phys. Phys. Rev. Applied Phys. Rev. A Phys. Rev. B Phys. Rev. C Phys. Rev. D Phys. Rev. E Phys. Rev. ST Accel. Beams Phys. Rev. ST Phys. Educ. Res. Phys. Rev. Phys. Rev. (Series I) Physics
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