Next Higgs? Atom Smasher Probes Highest Energies Yet
Particles created from the proton collision stream out from the center of the Compact Muon Solenoid detector. Credit: CERN Enlarge
Scientists at the world’s largest atom smasher have made a precise tally of the jumbled cascade of particles produced when two proton beams are smashed together. The results could help researchers discover new types of particles, akin to the now-famous Higgs boson.
Researchers at the Large Hadron Collider (LHC) in Switzerland sent two beams of protons hurtling in opposite directions and crashed them together at the highest energy level yet achieved at the LHC. The research is part of the CMS experiment, which stands for Compact MuonSolenoid. For each of the 150,000 proton-proton collisions the researchers identified, about 22 charged particles (hadrons) were produced.
The scientists wanted to create a snapshot of a “typical” collision between two proton beams, which could help the researchers sift through background noise for signs of new effects. Previous models to make predictions for detecting new particles rely on estimates with an uncertainty of 30 to 40 percent, which could be problematic for detecting rare particles, the researchers said. [Beyond Higgs: 5 Elusive Particles That May Lurk in the Universe]
To get a precise count of the number of particles produced in an average proton collision, the team analyzed data with the LHC’s magnet turned off. This meant the scientists could accurately count the number of charged particles, because they arrive at the CMS detector itself rather bending from the magnetic field and ending up in the main collider’s beam pipe, Yen-Jie Lee, an assistant professor of physics at the Massachusetts Institute of Technology and one of the study’s lead researchers, said in a statement.
The LHC is an underground ring measuring about 16 miles (27 kilometers) in circumference. It accelerates particles to nearly the speed of light using powerful magnets. The CMS experiment is one of a handful of detectors built into the LHC machine.
The energy intensity at the atom smasher has increased by 60 percent — from about 7 teraelectronvolts (TeV) to 13 TeV — since its first run, which lasted from 2010 to 2013. This is still a tiny amount of energy; 1 TeV is about the energy of motion of a flying mosquito. Within a proton though, this is squeezed into a space about a million, million times smaller than a mosquito, according to the EuropeanOrganization for Nuclear Research (CERN), which operates the LHC.
The LHC’s energy boost means that 30 percent more particles are produced per collision, the researchers found.
“At this high intensity, we will observe hundreds of millions of collisions each second,” Lee said.
The increased energy also gives physicists a better chance of discovering new particles like the Higgs boson, which was first detected in 2012. According to Albert Einstein’s equation e = mc2, the higher the energy (e) of the experiment, the higher the mass (m) of the new particles could be.