On the trail of dark energy: physicists propose Higgs boson 'portal'


August 9, 2013

One of the biggest mysteries in contemporary particle physics and cosmology is why dark energy, which is observed to dominate energy density of the universe, has a remarkably small (but not zero) value. This value is so small, it is perhaps 120 orders of magnitude less than would be expected based on fundamental physics.

Resolving this problem, often called the cosmological constant problem, has so far eluded theorists. Download Full Image

Now, two physicists – Lawrence Krauss of Arizona State University and James Dent of the University of Louisiana-Lafayette – suggest that the recently discovered Higgs boson could provide a possible “portal” to physics that could help explain some of the attributes of the enigmatic dark energy, and help resolve the cosmological constant problem.

In their paper, “Higgs Seesaw Mechanism as a Source for Dark Energy,” Krauss and Dent explore how a possible small coupling between the Higgs particle, and possible new particles likely to be associated with what is conventionally called the Grand Unified Scale – a scale perhaps 16 orders of magnitude smaller than the size of a proton, at which the three known non-gravitational forces in nature might converge into a single theory – could result in the existence of another background field in nature in addition to the Higgs field, which would contribute an energy density to empty space of precisely the correct scale to correspond to the observed energy density.

The paper was published online, Aug. 9, in Physical Review Letters.

Current observations of the universe show it is expanding at an accelerated rate. But this acceleration cannot be accounted for on the basis of matter alone. Putting energy in empty space produces a repulsive gravitational force opposing the attractive force produced by matter, including the dark matter that is inferred to dominate the mass of essentially all galaxies, but which doesn’t interact directly with light and, therefore, can only be estimated by its gravitational influence. 

Because of this phenomenon and because of what is observed in the universe, it is thought that such ‘dark energy’ contributes up to 70 percent of the total energy density in the universe, while observable matter contributes only 2 to 5 percent, with the remaining 25 percent or so coming from dark matter.

The source of this dark energy and the reason its magnitude matches the inferred magnitude of the energy in empty space is not currently understood, making it one of the leading outstanding problems in particle physics today.

“Our paper makes progress in one aspect of this problem,” said Krauss, a Foundation Professor in the School of Earth and Space Exploration and Physics in ASU's College of Liberal Arts and Sciences, and the director of the Origins Project at ASU. “Now that the Higgs boson has been discovered, it provides a possible 'portal' to physics at much higher energy scales through very small possible mixings and couplings to new scalar fields which may operate at these scales.”  

“We demonstrate that the simplest small mixing, related to the ratios of the scale at which electroweak physics operates, and a possible Grand Unified Scale, produces a possible contribution to the vacuum energy today of precisely the correct order of magnitude to account for the observed dark energy,” Krauss explained. “Our paper demonstrates that a very small energy scale can at least be naturally generated within the context of a very simple extension of the standard model of particle physics.”

While a possible advance in understanding the origin of dark energy, Krauss said the construct is only one step in the direction of understanding its mysteries.

“The deeper problem of why the known physics of the standard model does not contribute a much larger energy to empty space is still not resolved,” he said.

Associate Director, Media Relations & Strategic Communications

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ASU celebrates start of new academic year


August 9, 2013

Welcome back, Sun Devils! This fall, ASU is continuing to be the university of choice for students from Arizona and elsewhere as it welcomes a record number of students, including more than 12,500 students who will be moving into campus residence halls Aug. 16-21. (Visit the Fall Welcome site for more details.)

Once students have settled in, they can check out more than 100 individual events during ASU’s Fall Welcome, Aug. 15-20. These events are specifically aimed at helping new Sun Devils become familiar with the university, leading up to the first day of classes on Aug. 22. Download Full Image

Over the years, ASU has become one of the best universities in the world – noted for excellence of its academic and research programs, the quality of its graduates, prestige of its faculty and its commitment to important initiatives like entrepreneurship and sustainability. ASU is continuing its commitment to providing an environment that is conducive to intellectual growth and healthy living. Beginning Aug. 1, the university joined nearly 800 schools across the nation by going completely tobacco free. The initiative was spearheaded by students and supported by the University Staff Council and the faculty Academic Senate as part of a larger effort to promote health and wellness in the ASU community. Students at the Tempe campus will also notice the university’s recent introduction of Walk-Only Zones, designed to increase pedestrian safety and reduce vehicle congestion on heavily travelled campus malls.

To learn more about everything you need to know for the new year, check out the stories below.

 

West campus move-in

More than 12,500 students set to move in Aug. 16-21

Arizona State University welcomes the class of 2017, including more than 12,500 students moving into campus residence halls Aug. 16-21, for the 2013-2014 academic year. read more

 

 

Sun Devil Welcome

Fall Welcome celebrates class of 2017

Join Arizona State University in welcoming new students and their families to campus by attending Fall Welcome activities, Aug. 15-20. read more

 

 

tobacco free logo

ASU is now tobacco free

Arizona State University is now tobacco free, joining approximately 800 colleges and universities nationwide that have kicked the habit. read more

 

 

Cady Mall

Walk-Only Zones make your campus trips safer

Starting this fall, Walk-Only Zones will be enforced to increase pedestrian safety and reduce vehicle congestion. From 8 a.m.-4 p.m., Monday-Friday, no one may ride, drive or park wheeled vehicles in these designated zones. read more

 

 

ASU Alert icon

Start the semester with safety in mind

ASU’s Police Department, the Tempe Police Department and several officers from other agencies are conducting a joint awareness campaign during the first weeks of school to enforce traffic laws and alcohol violations. read more

 

 

students walking on palm walk

asu welcomes record freshman class

This fall, Arizona State University welcomes a freshman class that sets new records on many levels. The new class includes 10,149 academically distinguished, diverse Sun Devils from 50 states and 71 countries. read more

 

 

students walking on tempe campus

record number of students choose ASU

ASU continues to draw record numbers of academically qualified students who are eager to learn and make their mark on the world. As the fall 2013 semester begins Aug. 22, the university anticipates an enrollment of slightly more than 76,000 undergraduate and graduate students. read more

 

 

Manzanita Hall

university housing welcomes students to campus residential living

ASU welcomed more than 12,500 residents across four of ASU’s locations this week, including more than 800 students into the newly renovated 215,000-square-foot Manzanita Hall. read more

 

 

Camp Solera 2013

camp solera welcomes West campus freshmen

More than 200 freshmen participated in Camp Solera, a three-day experience designed to build class unity among West campus students. read more

 

 

NROTC freshmen

Naval ROTC welcomes freshmen to ASU

Arriving before most other students at Arizona State, more than 60 prospective Navy and Marine Corps midshipmen were introduced to college and military life during four intense days of physical fitness training, personal and professional development classes, swim and drill instruction. read more

 

Lisa Robbins

editor/publisher, Media Relations and Strategic Communications

480-965-9370