The “AMS Days at CERN” event is set to spotlight the most recent findings from the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station (ISS). This three-day gathering will attract some of the world’s foremost theoretical physicists and leading researchers from prominent cosmic ray experiments, including IceCube, Pierre Auger Observatory, Fermi-LAT, H.E.S.S., CTA, the Telescope Array, JEM-EUSO, and ISS-CREAM.
Purpose of the Event
The primary goal of this scientific symposium is to explore the connections between AMS findings and those from other significant cosmic ray research initiatives. During the event, members of the AMS international collaboration will present their latest results, offering a comprehensive view of current advancements in cosmic ray physics.
AMS Overview and Achievements
As the sole major particle physics experiment on the ISS, AMS has achieved remarkable milestones. Over its first four years in orbit, AMS has recorded over 60 billion cosmic ray events, encompassing electrons, positrons, protons, antiprotons, and various nuclei (such as helium, lithium, boron, carbon, and oxygen) at energies reaching multi-TeV levels. Scheduled to operate on the ISS until at least 2024, AMS will continue to gather and analyze extensive data, enhancing our understanding of cosmic rays and the underlying physics.
Key Findings and Implications
The AMS experiment has yielded pivotal insights into the positron fraction, the electron and positron spectra, and the combined electron-positron spectrum. These observations suggest potential dark matter interactions, as they cannot be fully explained by current models of ordinary cosmic ray collisions. Alternative theories propose new astrophysical sources, like pulsars, or novel acceleration and propagation mechanisms, such as those involving supernova remnants.
To determine whether the observed phenomena are attributable to dark matter, AMS is conducting measurements to observe how the positron fraction decreases beyond its peak and to analyze the antiproton-to-proton ratio. Intriguingly, the antiproton-to-proton ratio remains constant between 20 GeV and 450 GeV kinetic energy, a trend that cannot be accounted for by secondary production from ordinary cosmic ray collisions or by a pulsar origin. These latest findings will be further detailed during the “AMS Days at CERN” and in upcoming publications.
Additional Studies and Future Directions
A thorough understanding of the processes behind ordinary cosmic ray collisions is essential to interpret the AMS results accurately. The AMS Collaboration will also share recent advancements in the precision studies of nuclei spectra, including protons, helium, and lithium, up to multi-TeV energies.
A notable upcoming publication in Physical Review Letters will present the latest data on the proton flux in cosmic rays from 1 GV to 1.8 TV rigidity, based on 300 million proton events. The AMS results reveal a distinct behavior change in proton flux at approximately 300 GV rigidity, deviating from all previous experimental observations.
Equally surprising is the discovery that the helium flux, derived from 50 million events, exhibits a nearly identical unexpected behavior to the proton flux. AMS is actively investigating the behavior of other nuclei to uncover the origin of these anomalies.