Argonne National Laboratory

Article | Argonne National Laboratory

Researchers create enormous simulation of proton collisions

By
JARED SAGOFF
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This image shows what happens in a detector after colliding two protons, each with an energy of roughly 50 TeV. This single collision event was taken from a simulation of roughly 400 million events. Blue lines represent the tracks of charged particles, red lines represent electrons and muons. Yellow cones represent hadronic jets with energies above 3 TeV. Image by Sergei Chekanov

Scientists from the U.S. Department of Energy’s Argonne National Laboratory and the University of Chicago have created one of the world’s largest samples of Monte Carlo simulated proton-proton collisions. The data sample contains 400 million events, each of which contains 5500 particles on average, totaling more than 2 trillion generated particles. Each particle is characterized by four-momentum, position and several quantum numbers.

The created events correspond to a complete sample of Standard Model events with transverse momentum of jets above 2.7 TeV. Such an event sample is expected to be produced by a future hadron collider that surpasses the Large Hadron Collider (LHC). This event sample provides the background for potential new experiments to discover new physics at such a collider. The conceptual design of such a collider will be delivered before the end of 2018 by CERN, the European Organization for Nuclear Research. Similar studies are being pursued in evaluation of a future 100 TeV collider machine, which is under discussion in the US and China. 

The Monte Carlo simulated events were produced by Argonne and University of Chicago scientists as a part of commissioning of the ATLAS Connect virtual cluster service, a project led by the Computation Institute, and deployed in preparation for the upcoming LHC Run 2. The event sample was created using 15% of the capacity of ATLAS Connect during 5 days of tests.

Larger samples of Monte Carlo simulated events have previously been created by the LHC experiments and by a simulation group during the US long-term planning study of the American Physical Society’s Division of Particles and Fields. However, those samples were aggregated over a substantially longer period of time and used lower collision energies (i.e. a smaller number of particles per event) and lower integrated luminosities.

The simulated Monte Carlo events are available to the high-energy physics community for studies focused on the physics potential of a future 100 TeV proton-proton collider machine. The event files are publicly available from a database maintained by the ATLAS Analysis Support Center.

The work was supported by the U.S. Department of Energy’s Office of Science.