Sunday, April 5, 2015


Large Hadron Collider Begins Second Run
University of Maryland Researchers Continue Search for New Particles, including Dark Matter Particle 

The world’s most powerful particle accelerator is about to begin its second act. After two years of upgrades and repairs, proton beams are once again circulating around the Large Hadron Collider (LHC), located at the CERN laboratory near Geneva, Switzerland.

During the LHC’s second run, University of Maryland physicists will continue looking for new particles, including those that make up dark matter. Although the nature of dark matter and its counterpart, dark energy, remain a complete mystery, taken together they make up a total of around 95 percent of the universe.

The signature that will indicate the dark matter particle is known as missing transverse energy. UMD physicists are very familiar with this measurement, as they are a leading institution in the missing transverse energy group of the LHC’s Compact Muon Solenoid (CMS) detector. And they already have a head start: during the first LHC run, UMD’s Sarah Eno managed a group that produced three dark matter search results.

UMD physicists will also harness the LHC to investigate the origin of matter-antimatter asymmetry in the universe. When the Big Bang created matter, it also created an equal quantity of antimatter, made up of particles with identical mass but an opposite electrical charge. For as-yet unknown reasons, antimatter is no longer common in the universe, but can be recreated in particle accelerators such as the LHC.

UMD’s Hassan Jawahery leads a group that will use the LHCb detector to study the “beauty” or “bottom” quark— hence the “b” in the detector’s name. The goal is to also produce and detect the antimatter counterpart to the beauty quark. Comparing the properties of these two complementary particles could reveal laws of nature that treat matter and antimatter differently.

During the LHC’s second run, particles will collide at a staggering 13 teraelectronvolts (TeV), which is 60 percent higher than any accelerator has achieved before. Higher energy collisions produce more particles and a greater number of heavy particles. This essentially allows researchers to look further back in time by creating a “soup” of interacting particles that could mimic the conditions of the universe just milliseconds after the Big Bang. University of Maryland chemists will study these heavy ion collisions during Run 2.

Several key members of the University of Maryland LHC team are available to comment on their work and the broader context of the LHC’s second run:

Last minute repairs delayed the run’s start date, but it restarted on April 5, 2015. The UMD team is available for comment at any time.

Media Relations Contact: Abby Robinson, 301-405-5845,

University of Maryland
College of Computer, Mathematical, and Natural Sciences
2300 Symons Hall
College Park, MD 20742

About the College of Computer, Mathematical, and Natural Sciences

The College of Computer, Mathematical, and Natural Sciences at the University of Maryland educates more than 7,000 future scientific leaders in its undergraduate and graduate programs each year. The college's 10 departments and more than a dozen interdisciplinary research centers foster scientific discovery with annual sponsored research funding exceeding $150 million.