Doe Science news source
The DOE Science News Source is a Newswise initiative to promote research news from the Office of Science of the DOE to the public and news media.
  • 2017-11-08 09:00:13
  • Article ID: 684808

New Study: Scientists Narrow Down the Search for Dark Photons Using Decade-Old Particle Collider Data

Analysis of data from the BaBar experiment rules out theorized particle's explanation for muon mystery

  • Credit: SLAC National Accelerator Laboratory

    The BaBar detector at SLAC National Accelerator Laboratory.

  • Credit: Muon g-2 Collaboration

    This chart shows the search area (green) explored in an analysis of BaBar data where dark photon particles have not been found, compared with other experiments’ search areas. The red band shows the favored search area to show whether dark photons are causing the so-called “g-2 anomaly,” and the white areas are among the unexplored territories for dark photons.

In its final years of operation, a particle collider in Northern California was refocused to search for signs of new particles that might help fill in some big blanks in our understanding of the universe.

A fresh analysis of this data, co-led by physicists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), limits some of the hiding places for one type of theorized particle – the dark photon, also known as the heavy photon – that was proposed to help explain the mystery of dark matter.

The latest result, published in the journal Physical Review Letters by the roughly 240-member BaBar Collaboration, adds to results from a collection of previous experiments seeking, but not yet finding, the theorized dark photons.

“Although it does not rule out the existence of dark photons, the BaBar results do limit where they can hide, and definitively rule out their explanation for another intriguing mystery associated with the property of the subatomic particle known as the muon,” said Michael Roney, BaBar spokesperson and University of Victoria professor.

Dark matter, which accounts for an estimated 85 percent of the total mass of the universe, has only been observed by its gravitational interactions with normal matter. For example, the rotation rate of galaxies is much faster than expected based on their visible matter, suggesting there is “missing” mass that has so far remained invisible to us.

So physicists have been working on theories and experiments to help explain what dark matter is made of – whether it is composed of undiscovered particles, for example, and whether there may be a hidden or “dark” force that governs the interactions of such particles among themselves and with visible matter. The dark photon, if it exists, has been put forward as a possible carrier of this dark force.

Using data collected from 2006 to 2008 at SLAC National Accelerator Laboratory in Menlo Park, California, the analysis team scanned the recorded byproducts of particle collisions for signs of a single particle of light – a photon – devoid of associated particle processes.

The BaBar experiment, which ran from 1999 to 2008 at SLAC, collected data from collisions of electrons with positrons, their positively charged antiparticles. The collider driving BaBar, called PEP-II, was built through a collaboration that included SLAC, Berkeley Lab, and Lawrence Livermore National Laboratory. At its peak, the BaBar Collaboration involved over 630 physicists from 13 countries.

BaBar was originally designed to study the differences in the behavior between matter and antimatter involving a b-quark. Simultaneously with a competing experiment in Japan called Belle, BaBar confirmed the predictions of theorists and paved the way for the 2008 Nobel Prize. Berkeley Lab physicist Pier Oddone proposed the idea for BaBar and Belle in 1987 while he was the Lab’s Physics division director.

The latest analysis used about 10 percent of BaBar’s data – recorded in its final two years of operation. Its data collection was refocused on finding particles not accounted for in physics’ Standard Model – a sort of rulebook for what particles and forces make up the known universe.

“BaBar performed an extensive campaign searching for dark sector particles, and this result will further constrain their existence,” said Bertrand Echenard, a research professor at Caltech who was instrumental in this effort.

Yury Kolomensky, a physicist in the Nuclear Science Division at Berkeley Lab and a faculty member in the Department of Physics at UC Berkeley, said, “The signature (of a dark photon) in the detector would be extremely simple: one high-energy photon, without any other activity.”

A number of the dark photon theories predict that the associated dark matter particles would be invisible to the detector. The single photon, radiated from a beam particle, signals that an electron-positron collision has occurred and that the invisible dark photon decayed to the dark matter particles, revealing itself in the absence of any other accompanying energy.

When physicists had proposed dark photons in 2009, it excited new interest in the physics community, and prompted a fresh look at BaBar’s data. Kolomensky supervised the data analysis, performed by UC Berkeley undergraduates Mark Derdzinski and Alexander Giuffrida.

“Dark photons could bridge this hidden divide between dark matter and our world, so it would be exciting if we had seen it,” Kolomensky said.

The dark photon has also been postulated to explain a discrepancy between the observation of a property of the muon spin and the value predicted for it in the Standard Model. Measuring this property with unprecedented precision is the goal of the Muon g-2 (pronounced gee-minus-two) Experiment at Fermi National Accelerator Laboratory.

Earlier measurements at Brookhaven National Laboratory had found that this property of muons – like a spinning top with a wobble that is ever-slightly off the norm – is off by about 0.0002 percent from what is expected. Dark photons were suggested as one possible particle candidate to explain this mystery, and a new round of experiments begun earlier this year should help to determine whether the anomaly is actually a discovery.

The latest BaBar result, Kolomensky said, largely “rules out these dark photon theories as an explanation for the g-2 anomaly, effectively closing this particular window, but it also means there is something else driving the g-2 anomaly if it’s a real effect.”

It’s a common and constant interplay between theory and experiments, with theory adjusting to new constraints set by experiments, and experiments seeking inspiration from new and adjusted theories to find the next proving grounds for testing out those theories.

Scientists have been actively mining BaBar’s data, Roney said, to take advantage of the well-understood experimental conditions and detector to test new theoretical ideas.

“Finding an explanation for dark matter is one of the most important challenges in physics today, and looking for dark photons was a natural way for BaBar to contribute,” Roney said, adding that many experiments in operation or planned around the world are seeking to address this problem.

An upgrade of an experiment in Japan that is similar to BaBar, called Belle II,  turns on next year. “Eventually, Belle II will produce 100 times more statistics compared to BaBar,” Kolomensky said. “Experiments like this can probe new theories and more states, effectively opening new possibilities for additional tests and measurements.”

“Until Belle II has accumulated significant amounts of data, BaBar will continue for the next several years to yield new impactful results like this one,” Roney said.

The study featured participation by the international BaBar collaboration, which includes researchers from about 66 institutions in the U.S., Canada, France, Spain, Italy, Norway, Germany, Russia, India, Saudi Arabia, U.K., the Netherlands, and Israel. The work was supported by the U.S. Department of Energy’s Office of Science and the National Science Foundation; the Natural Sciences and Engineering Research Council in Canada; CEA and CNRS-IN2P3 in France; BMBF and DFG in Germany; INFN in Italy; FOM in the Netherlands; NFR in Norway; MES in Russia; MINECO in Spain; STFC in the U.K.; and BSF in Israel and the U.S. Individuals involved with this study have received support from the Marie Curie EIF in the European Union, and the Alfred P. Sloan Foundation in the U.S.

###

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

X
X
X
  • Filters

  • × Clear Filters

Solar Cell Discovery Opens a New Window to Powering Tomorrow's Cities

Windows that generate electricity may have a clearer path to prominent roles in buildings of the future due to an Argonne-led discovery.

How the Earth Stops High-Energy Neutrinos in Their Tracks

A research collaboration including scientists from Berkeley Lab has demonstrated that the Earth stops high-energy neutrinos - particles that only very rarely interact with matter.

Kentucky Researchers First to Produce High Grade Rare Earths From Coal

University of Kentucky researchers have produced nearly pure rare earth concentrates from Kentucky coal using an environmentally-conscious and cost-effective process, a groundbreaking accomplishment in the energy industry.

Watching Atoms Move in Hybrid Perovskite Crystals Reveals Clues to Improving Solar Cells

The discovery of nanoscale changes deep inside hybrid perovskites could shed light on developing low-cost, high-efficiency solar cells. Using X-ray beams and lasers, a team of researchers led by the University of California San Diego discovered how the movement of ions in hybrid perovskites causes certain regions within the material to become better solar cells than other parts.

Quantum Dots Amplify Light with Electrical Pumping

In a breakthrough development, Los Alamos scientists have shown that they can successfully amplify light using electrically excited films of the chemically synthesized semiconductor nanocrystals known as quantum dots.

The Challenge of Estimating Alaska's Soil Carbon Stocks

A geospatial analysis determined the optimal distribution of sites needed to reliably estimate Alaska's vast soil carbon.

Strain-Free Epitaxy of Germanium Film on Mica

Germanium was the material of choice in the early history of electronic devices, and due to its high charge carrier mobility, it's making a comeback. It's generally grown on expensive single-crystal substrates, adding another challenge to making it sustainably viable for most applications. To address this aspect, researchers demonstrate an epitaxy method that incorporates van der Waals' forces to grow germanium on mica. They discuss their work in the Journal of Applied Physics.

Unplugging the Cellulose Biofuel Bottleneck

Molecular-level understanding of cellulose structure reveals why it resists degradation and could lead to cost-effective biofuels.

Detailed View of Immune Proteins Could Lead to New Pathogen-Defense Strategies

Biologists at Berkeley Lab and UC Berkeley used cryo-EM to resolve the structure of a ring of proteins used by the immune system to summon support when under attack, providing new insight into potential strategies for protection from pathogens. The researchers captured the high-resolution image of a protein ring, called an inflammasome, as it was bound to flagellin, a protein from the whiplike tail used by bacteria to propel themselves forward.

Unlocking the Secrets of Ebola

Scientists have identified a set of biomarkers that indicate which patients infected with the Ebola virus are most at risk of dying from the disease. The results come from one of the most in-depth studies ever of blood samples from patients with Ebola.


  • Filters

  • × Clear Filters

Five Brookhaven Lab Scientists Named 2017 American Physical Society Fellows

Anatoly Frenkel, Morgan May, Rachid Nouicer, Eric Stach, and Peter Steinberg were recognized for their outstanding contributions to astrophysics, materials physics, and nuclear physics.

Argonne Appoints Chief of Staff

Megan Clifford has been named Chief of Staff at the U.S. Department of Energy's (DOE) Argonne National Laboratory, effective January 1, 2018.

Jefferson Lab Scientist Selected to Receive Francis Slack Award

Dr. Hari Areti, has been selected to receive the Francis G. Slack Award, established by the Southeastern Section of the American Physical Society, to honor excellence in service to Physics in the Southeastern U.S.

ORNL Wins Nine R&D 100 Awards

Researchers at the Department of Energy's Oak Ridge National Laboratory have received nine R&D 100 Awards in recognition of their significant advancements in science and technology.

Argonne Scientists Capture Several R&D 100 Awards

Innovative technologies developed by researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory recently earned several R&D 100 Awards.

Eight Los Alamos innovations win R&D 100 Awards

Eight Los Alamos National Laboratory technologies won R&D 100 Awards last week at R&D Magazine's annual ceremony in Orlando, Florida.

Physicist David Gates Named Editor-in-Chief of Plasma, a New Online Journal

Article announces David Gates' appointment as editor-in-chief of Plasma magazine

Argonne to Install Comanche System to Explore ARM Technology for High-Performance Computing

Argonne National Laboratory is collaborating with Hewlett Packard Enterprise (HPE) to provide system software expertise and a development ecosystem for a future high-performance computing (HPC) system based on 64-bit ARM processors.

CANDLE Shines in 2017 HPCwire Readers' and Editors' Choice Awards

Argonne National Laboratory has been recognized in the annual <em>HPCwire</em> Readers' and Editors' Choice Awards, presented at the 2017 International Conference for High Performance Computing, Networking, Storage and Analysis (SC17), in Denver, Colorado.

SLAC's Helen Quinn Honored with 2018 Benjamin Franklin Medal in Physics

Helen Quinn, a professor emerita at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University, will receive the 2018 Benjamin Franklin Medal in Physics - one of eight prestigious Franklin Institute Awards that will be handed out in Philadelphia next April.


  • Filters

  • × Clear Filters

The Challenge of Estimating Alaska's Soil Carbon Stocks

A geospatial analysis determined the optimal distribution of sites needed to reliably estimate Alaska's vast soil carbon.

Unplugging the Cellulose Biofuel Bottleneck

Molecular-level understanding of cellulose structure reveals why it resists degradation and could lead to cost-effective biofuels.

How Fungal Enzymes Break Down Plant Cell Walls

Lignocellulose-degrading enzyme complexes could improve biofuel production.

Stretching to Perfection of 2-D Semiconductors

Scientists use heat and mismatched surfaces to stretch films that can potentially improve the efficient operation of devices.

Simple is Beautiful in Quantum Computing

Defect spins in diamond were controlled with a simpler, geometric method, leading to faster computing.

The Effect of Hurricanes on Puerto Rico's Dry Forests

More frequent storms turn forests from carbon source to sink.

A Chemical Thermometer for Tropical Forests

Monoterpene measures how certain forests respond to heat stress.

Where a Leaf Lands and Lies Influences Carbon Levels in Soil for Years to Come

Whether carbon comes from leaves or needles affects how fast it decomposes, but where it ends up determines how long it's available.

Twisting Molecule Wrings More Power from Solar Cells

Readily rotating molecules let electrons last, resulting in higher solar cell efficiency.

Rules Are Only Suggestions in Heavy Elements

The arrangement of electrons in an exotic human-made element shows that certain properties of heavy elements cannot be predicted using lighter ones.


Spotlight

Tuesday October 03, 2017, 01:05 PM

Stairway to Science

Argonne National Laboratory

Thursday September 28, 2017, 12:05 PM

After-School Energy Rush

Argonne National Laboratory

Thursday September 28, 2017, 10:05 AM

Bringing Diversity Into Computational Science Through Student Outreach

Brookhaven National Laboratory

Thursday September 21, 2017, 03:05 PM

From Science to Finance: SLAC Summer Interns Forge New Paths in STEM

SLAC National Accelerator Laboratory

Thursday September 07, 2017, 02:05 PM

Students Discuss 'Cosmic Opportunities' at 45th Annual SLAC Summer Institute

SLAC National Accelerator Laboratory

Thursday August 31, 2017, 05:05 PM

Binghamton University Opens $70 Million Smart Energy Building

Binghamton University, State University of New York

Wednesday August 23, 2017, 05:05 PM

Widening Horizons for High Schoolers with Code

Argonne National Laboratory

Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

Department of Energy, Office of Science

Friday March 24, 2017, 10:40 AM

Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

Brookhaven National Laboratory

Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

Oak Ridge National Laboratory

Tuesday November 08, 2016, 12:05 PM

Internship Program Helps Foster Development of Future Nuclear Scientists

Oak Ridge National Laboratory

Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

Thomas Jefferson National Accelerator Facility

Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

Thomas Jefferson National Accelerator Facility

Tuesday February 02, 2016, 10:05 AM

Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

University of California San Diego

Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

Rensselaer Polytechnic Institute (RPI)

Friday September 10, 2010, 12:40 PM

Ithaca College Will Host Regional Clean Energy Summit

Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

Texas Tech University

Friday May 07, 2010, 04:20 PM

Creighton University to Offer New Alternative Energy Program

Creighton University

Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

JETS Junior Engineering Technical Society

Wednesday April 21, 2010, 12:30 PM

Students Using Solar Power To Create Sustainable Solutions for Haiti, Peru

Rensselaer Polytechnic Institute (RPI)

Wednesday March 03, 2010, 07:00 PM

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage

Rensselaer Polytechnic Institute (RPI)

Thursday February 04, 2010, 02:00 PM

Turning Exercise into Electricity

Furman University

Thursday November 12, 2009, 12:45 PM

Campus Leaders Showing the Way to a Sustainable, Clean Energy Future

National Wildlife Federation (NWF)

Tuesday November 03, 2009, 04:20 PM

Furman University Receives $2.5 Million DOE Grant for Geothermal Project

Furman University

Thursday September 17, 2009, 02:45 PM

Could Sorghum Become a Significant Alternative Fuel Source?

Salisbury University

Wednesday September 16, 2009, 11:15 AM

Students Navigating the Hudson River With Hydrogen Fuel Cells

Rensselaer Polytechnic Institute (RPI)

Wednesday September 16, 2009, 10:00 AM

College Presidents Flock to D.C., Urge Senate to Pass Clean Energy Bill

National Wildlife Federation (NWF)

Wednesday July 01, 2009, 04:15 PM

Northeastern Announces New Professional Master's in Energy Systems

Northeastern University

Friday October 12, 2007, 09:35 AM

Kansas Rural Schools To Receive Wind Turbines

Kansas State University

Thursday August 17, 2006, 05:30 PM

High Gas Prices Here to Stay, Says Engineering Professor

Rowan University





Showing results

0-4 Of 2215