A5105763095- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Astrophysics and Cosmic Phenomena
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Ionosphere and magnetosphere dynamics
- Radiation Detection and Scintillator Technologies
- Atmospheric Ozone and Climate
- Nuclear physics research studies
- Medical Imaging Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-Plasma Interactions and Diagnostics
- Muon and positron interactions and applications
Massachusetts Institute of Technology
2016-2025
Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca
2020
Kyungpook National University
2006
University of Michigan–Ann Arbor
1995-2005
IIT@MIT
1998-2005
University of Maryland, College Park
2005
Istituto Nazionale di Fisica Nucleare, Sezione di Bologna
2000-2002
University of Bologna
2000-2002
RWTH Aachen University
1990-2000
National Institute for Subatomic Physics
1982-2000
A precision measurement by the Alpha Magnetic Spectrometer on International Space Station of positron fraction in primary cosmic rays energy range from 0.5 to 350 GeV based $6.8\ifmmode\times\else\texttimes\fi{}{10}^{6}$ and electron events is presented. The very accurate data show that steadily increasing 10 $\ensuremath{\sim}250\text{ }\text{ }\mathrm{GeV}$, but, 20 250 GeV, slope decreases an order magnitude. spectrum shows no fine structure, ratio observable anisotropy. Together, these...
A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge dependence important understanding origin, acceleration, and propagation rays. We present detailed variation spectral index for first time. The progressively hardens at high rigidities.Received 6 March 2015DOI:https://doi.org/10.1103/PhysRevLett.114.171103This article available under terms Creative Commons Attribution 3.0...
Measurements of the positron fraction in high energy cosmic rays using space-borne Alpha Magnetic Spectrometer have been extended to energies 500 GeV. The new results show that stops increasing with at around 200
Precision measurements by the Alpha Magnetic Spectrometer on International Space Station of primary cosmic-ray electron flux in range 0.5 to 700 GeV and positron 500 are presented. The each require a description beyond single power-law spectrum. Both change their behavior at ∼30 but fluxes significantly different magnitude energy dependence. Between 20 200 spectral index is harder than index. determination differing indices versus new observation provides important information origins...
Knowledge of the precise rigidity dependence helium flux is important in understanding origin, acceleration, and propagation cosmic rays. A measurement primary rays with (momentum/charge) from 1.9 GV to 3 TV based on 50 million events presented compared proton flux. The detailed variation spectral index for first time. progressively hardens at rigidities larger than 100 GV. similar that though magnitudes are different. Remarkably, ratio increases up 45 then becomes constant; above well...
A precision measurement by AMS of the antiproton flux and antiproton-to-proton ratio in primary cosmic rays absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} events 2.42×10^{9} proton events. The fluxes ratios charged elementary particles are also presented. In ∼60 ∼500 GV, p[over ¯], p, positron e^{+} found have nearly identical dependence electron e^{-} exhibits a different dependence. Below 60 (p[over ¯]/p), ¯]/e^{+}), (p/e^{+}) each reaches maximum. From show no...
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting unique, long-duration mission of fundamental research in space. objectives include precise studies origin dark matter, antimatter, and cosmic rays as well exploration new phenomena. Following 16-year period construction testing, precursor flight Shuttle, AMS was installed ISS May 19, 2011. In this report we present results based 120 billion charged ray events up...
Knowledge of the rigidity dependence boron to carbon flux ratio (B/C) is important in understanding propagation cosmic rays. The precise measurement B/C from 1.9 GV 2.6 TV, based on 2.3 million and 8.3 nuclei collected by AMS during first 5 years operation, presented. detailed variation with spectral index reported for time. does not show any significant structures contrast many ray models that require such at high rigidities. Remarkably, above 65 GV, well described a single power law R^{Δ}...
A measurement of the cosmic ray positron fraction e+/(e++e−) in energy range 1–30 GeV is presented. The based on data taken by AMS-01 experiment during its 10 day Space Shuttle flight June 1998. proton background suppression order 106 reached identifying converted bremsstrahlung photons emitted from positrons.
We report the observation of new properties primary cosmic rays He, C, and O measured in rigidity (momentum/charge) range 2 GV to 3 TV with 90×10^{6} helium, 8.4×10^{6} carbon, 7.0×10^{6} oxygen nuclei collected by Alpha Magnetic Spectrometer (AMS) during first five years operation. Above 60 GV, these three spectra have identical dependence. They all deviate from a single power law above 200 harden an way.
We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in range 0.5 GeV to 1 TeV based on analysis 10.6 million events collected by AMS. The statistics and resolution AMS provide precision flux. is smooth reveals new distinct information. Above 30.2 GeV, can be described single power law with spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).
Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million collected by the Alpha Magnetic Spectrometer International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties (a) a significant excess starting from 25.2±1.8 GeV compared lower-energy, power-law trend, (b) sharp dropoff above 284+91−64 GeV, (c) in entire range is well described sum term associated with produced collision rays, which dominates at low...
We report on the observation of new properties secondary cosmic rays Li, Be, and B measured in rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total 5.4×10^{6} nuclei collected by AMS during first five years operation aboard International Space Station. The Li fluxes have an identical dependence above 7 all three 30 Li/Be flux ratio 2.0±0.1. deviate from single power law 200 way. This behavior has also been observed measurement primary He, C, O but dependences are...
Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based $28.1\ifmmode\times\else\texttimes\fi{}{10}^{6}$ collected by Alpha Magnetic Spectrometer International Space Station. In entire electron and positron spectra have distinctly different magnitudes dependences. The flux exhibits a significant excess starting $42.{1}_{\ensuremath{-}5.2}^{+5.4}\text{ }\text{ }\mathrm{GeV}$ compared lower trends, but nature of this is above...
We present results over an 11-year Solar cycle of cosmic antiprotons based on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>1.1</a:mn><a:mo>×</a:mo><a:msup><a:mn>10</a:mn><a:mn>6</a:mn></a:msup></a:math> events in the rigidity range from 1.00 to 41.9 GV. The <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mover accent="true"><c:mi>p</c:mi><c:mo stretchy="false">¯</c:mo></c:mover></c:math> fluxes exhibit distinct properties. magnitude...
We present the precision measurement from May 2011 to 2017 (79 Bartels rotations) of proton fluxes at rigidities 1 60 GV and helium 1.9 based on a total 1×10^{9} events collected with Alpha Magnetic Spectrometer aboard International Space Station. This is in solar cycle 24, which has maximum April 2014. observed that, below 40 GV, flux show nearly identical fine structures both time relative amplitude. The amplitudes decrease increasing rigidity vanish above GV. are reduced during period,...
We report the observation of new properties primary iron (Fe) cosmic rays in rigidity range 2.65 GV to 3.0 TV with 0.62×106 nuclei collected by Alpha Magnetic Spectrometer experiment on International Space Station. Above 80.5 dependence ray Fe flux is identical He, C, and O fluxes, Fe/O ratio being constant at 0.155±0.006. This shows that unexpectedly belong same class which different from Ne, Mg, Si class.Received 2 October 2020Revised 22 November 2020Accepted 9 December...
We present high-statistics, precision measurements of the detailed time and energy dependence primary cosmic-ray electron flux positron over 79 Bartels rotations from May 2011 to 2017 in range 1 50 GeV. For first time, charge-sign dependent modulation during solar maximum has been investigated detail by leptons alone. Based on 23.5×10^{6} events, we report observation short-term structures timescale months coincident both flux. These are not visible e^{+}/e^{-} ratio. The across polarity...