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.
  • 2018-05-08 16:30:15
  • Article ID: 694237

The Weak Side of the Proton

Precision measurement of the proton's weak charge narrows the search for new physics.

  • Credit: DOE's Jefferson Lab

    The Q-weak experiment was conducted in Jefferson Lab's Experimental Hall C, and its goal was to very precisely measure the proton's weak charge, a term that quantifies the influence that the weak force can exert on protons. The Q-weak apparatus, shown here, was installed in the hall for the experimental run, which concluded in 2012.

A new result from the Q-weak experiment at the Department of Energy’s Thomas Jefferson National Accelerator Facility provides a precision test of the weak force, one of four fundamental forces in nature. This result, published recently in Nature, also constrains possibilities for new particles and forces beyond our present knowledge.

“Precision measurements like this one can act as windows into a world of potential new particles that otherwise might only be observable using extremely high-energy accelerators that are currently beyond the reach of our technical capabilities,” said Roger Carlini, a Jefferson Lab scientist and a co-spokesperson for the Q-weak Collaboration.

While the weak force is difficult to observe directly, its influence can be felt in our everyday world. For example, it initiates the chain of reactions that power the sun and it provides a mechanism for radioactive decays that partially heat the Earth’s core and that also enable doctors to detect disease inside the body without surgery.

Now, the Q-weak Collaboration has revealed one of the weak force’s secrets: the precise strength of its grip on the proton. They did this by measuring the proton’s weak charge to high precision, which they probed using the high-quality beams available at the Continuous Electron Beam Accelerator Facility, a DOE Office of Science User Facility.

The proton’s weak charge is analogous to its more familiar electric charge, a measure of the influence the proton experiences from the electromagnetic force. These two interactions are closely related in the Standard Model, a highly successful theory that describes the electromagnetic and weak forces as two different aspects of a single force that interacts with subatomic particles.

To measure the proton’s weak charge, an intense beam of electrons was directed onto a target containing cold liquid hydrogen, and the electrons scattered from this target were detected in a precise, custom-built measuring apparatus. The key to the Q-weak experiment is that the electrons in the beam were highly polarized – prepared prior to acceleration to be mostly “spinning” in one direction, parallel or anti-parallel to the beam direction. With the direction of polarization rapidly reversed in a controlled manner, the experimenters were able to latch onto the weak interaction’s unique property of parity (akin to mirror symmetry) violation, in order to isolate its tiny effects to high precision: a different scattering rate by about 2 parts in 10 million was measured for the two beam polarization states.

The proton’s weak charge was found to be QWp=0.0719±0.0045, which turns out to be in excellent agreement with predictions of the Standard Model, which takes into account all known subatomic particles and the forces that act on them. Because the proton’s weak charge is so precisely predicted in this model, the new Q-weak result provides insight into predictions of hitherto unobserved heavy particles, such as those that may be produced by the Large Hadron Collider (LHC) at CERN in Europe or future high energy particle accelerators.  

“This very challenging experimental result is yet another clue in the world-wide search for new physics beyond our current understanding. There is ample evidence the Standard Model of Particle physics provides only an incomplete description of nature’s phenomena, but where the breakthrough will come remains elusive,” said Timothy J. Hallman, Associate Director for Nuclear Physics of the Department of Energy Office of Science. “Experiments like Q-weak are pressing ever closer to finding the answer.”

For example, the Q-weak result has set limits on the possible existence of leptoquarks, which are hypothetical particles that can reverse the identities of two broad classes of very different fundamental particles – turning quarks (the building blocks of nuclear matter) into leptons (electrons and their heavier counterparts) and vice versa.

"After more than a decade of careful work, Q-weak not only informed the Standard Model, it showed that extreme precision can enable moderate-energy experiments to achieve results on par with the largest accelerators available to science," said Anne Kinney, Assistant Director for the Mathematical and Physical Sciences Directorate at the National Science Foundation. "Such precision will be important in the hunt for physics beyond the Standard Model, where new particle effects would likely appear as extremely tiny deviations. 

“It’s complementary information. So, if they find evidence for new physics in the future at the LHC, we can help identify what it might be, from the limits that we’re setting already in this paper,” said Greg Smith, Jefferson Lab scientist and Q-weak project manager.

The Q-weak Collaboration consists of about 100 scientists and more than 20 institutions. The experiment was funded by the U.S. Department of Energy Office of Science, the National Science Foundation, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Foundation for Innovation, with matching and in-kind contributions from a number of the collaborating institutions.

Contact: Kandice Carter, Jefferson Lab Communications Office, 757-269-7263, kcarter@jlab.org

                                                            -end-

Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy's Office of Science.

Jefferson Lab is supported by the Office of Science of the U.S. Department of Energy. The 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

Self-Assembling 3D Battery Would Charge in Seconds

A cross-campus collaboration led by Ulrich Wiesner, professor of engineering at Cornell University, has resulted in a novel energy storage device architecture that has the potential for lightning-quick charges for electronic devices.

Understanding the Generation of Light-Induced Electrical Current in Atomically Thin Nanomaterials

Scientists added an imaging capability to Brookhaven Lab's Center for Functional Nanomaterials that could provide the optoelectronic information needed to improve the performance of devices for power generation, communications, data storage, and lighting.

Diamond 'Spin-Off' Tech Could Lead to Low-Cost Medical Imaging and Drug Discovery Tools

An international team led by scientists at Berkeley Lab and UC Berkeley discovered how to exploit defects in nanoscale and microscale diamonds and potentially enhance the sensitivity of magnetic resonance imaging and nuclear magnetic resonance systems while eliminating the need for their costly and bulky superconducting magnets.

PROSPECTing For Antineutrinos

The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) has completed installation of a novel antineutrino detector that will probe the possible existence of a new form of matter - sterile neutrinos.

How to Cope with Cases of Mistaken Identity: MINERvA's Tale of Pions and Neutrinos

Neutral pion production is a major character in a story of mistaken identity worthy of an Agatha Christie novel.

Perfecting the Noise-Canceling Neutrino Detector

MicroBooNE neutrino experiment cuts through the noise, clearing the way for signals made by the hard-to-detect particle.

Supersonic Waves May Help Electronics Beat the Heat

Researchers at the Department of Energy's Oak Ridge National Laboratory made the first observations of waves of atomic rearrangements, known as phasons, propagating supersonically through a vibrating crystal lattice--a discovery that may dramatically improve heat transport in insulators and enable new strategies for heat management in future electronics devices.

Riding Bacterium to the Bank

Jet fuel, pantyhose and plastic soda bottles are all products currently derived from petroleum. Sandia National Laboratories scientists have demonstrated a new technology based on bioengineered bacteria that makes it feasible to produce all three from renewable plant sources.

Flexible, Highly Efficient Multimodal Energy Harvesting

A piezoelectric ceramic foam supported by a flexible polymer support provides a 10-fold increase in the ability to harvest mechanical and thermal energy over standard piezo composites, according to Penn State researchers.

PNNL Successfully Vitrifies Three Gallons of Radioactive Tank Waste

News Release RICHLAND, Wash. -- In a first-of-its-kind demonstration, researchers at the Department of Energy's Pacific Northwest National Laboratory have vitrified low-activity waste from underground storage tanks at Hanford, immobilizing the radioactive and chemical materials within a durable glass waste form.Approximately three gallons of low-activity Hanford tank waste were vitrified at PNNL's Radiochemical Processing Laboratory in April.


  • Filters

  • × Clear Filters

Power to the People

The University of Utah College of Engineering has received a $2 million grant to create a laboratory and develop new technology for communities with backup power sources, known as microgrids, so they can quickly and more securely operate in the event of a massive power outage due to a natural disaster or cyberattack.

The U. S. Department of Energy Announces $34 Million for Small Business Research and Development Grants

U.S. Energy Secretary Rick Perry announced that the Department of Energy will award 219 grants totaling $34 million to 183 small businesses in 41 states. Funded through DOE's Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs, today's selections are for Phase I research and development.

Raising the Heat to Lower the Cost of Solar Energy

Sandia National Laboratories will receive $10.5 million from the Department of Energy to research and design a cheaper and more efficient solar energy system.The work focuses on refining a specific type of utility-scale solar energy technology that uses mirrors to reflect and concentrate sunlight onto a receiver on a tower.

Solar Turbines, Inc. Selects Penn State to Establish Center of Excellence in Gas Turbines

After completing an extensive evaluation of institutions of higher learning in the United States and Europe, Solar Turbines Incorporated has chosen Penn State as a university partner to establish a center of excellence in gas turbines. The center involves numerous faculty across Penn State's College of Engineering.

ORNL Facility Receives American Nuclear Society's Historic Landmark Designation

The American Nuclear Society has designated the Radiochemical Engineering Development Center at the Department of Energy's Oak Ridge National Laboratory an ANS Nuclear Historic Landmark, recognizing more than 50 years of isotope production and nuclear fuel cycle research.

Steven Cowley named director of DOE's Princeton Plasma Physics Laboratory

Steven Cowley, a theoretical physicist and international authority on fusion energy, has been named director of the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), effective July 1.

Scientists Turn X-ray Laser Into World's Fastest Water Heater

Scientists have used a powerful X-ray laser at the Department of Energy's SLAC National Accelerator Laboratory to heat water from room temperature to 100,000 degrees Celsius in less than a tenth of a picosecond, or millionth of a millionth of a second.

PNNL Part of a New National Center for Near-Atomic Resolution of Biological Molecules

A collaboration between the Pacific Northwest National Laboratory and Oregon Health & Science University has been chosen as a national center for a Nobel Prize-winning method of imaging, cryo-electron microscopy, that is revolutionizing structural biology.

SLAC Will Open One of Three NIH National Service Centers for Cryo-Electron Microscopy

The National Institutes of Health announced today that it will establish a national service and training center for cryogenic electron microscopy research at the Department of Energy's SLAC National Accelerator Laboratory.

Planck Collaboration Wins 2018 Gruber Cosmology Prize

The Planck Team--including researchers in Lawrence Berkeley National Laboratory's (Berkeley Lab's) Computational Research and Physics divisions--have been awarded the 2018 Gruber Cosmology Prize.


  • Filters

  • × Clear Filters

The Secret to Measuring an Antineutrino's Energy

Scientists are developing better models that describe both neutrino and antineutrino data, which can offer insights into the nature of the universe.

How to Cope with Cases of Mistaken Identity: MINERvA's Tale of Pions and Neutrinos

Neutral pion production is a major character in a story of mistaken identity worthy of an Agatha Christie novel.

Perfecting the Noise-Canceling Neutrino Detector

MicroBooNE neutrino experiment cuts through the noise, clearing the way for signals made by the hard-to-detect particle.

Keeping Tabs on Polysulfides in Batteries

Optimizing lithium-sulfur battery electrolytes for long life.

Huge "Thermometer" Takes Temperatures of Tiny Samples

New spectroscopic technique measures heat in itty-bitty volumes that could reveal insights for electronics and energy technology.

Water, Water, Everywhere, but How Does It Flow?

Scientists use new X-ray technique to see how water moves at the molecular level.

Magnetized Plasmas That "Twist Light" Can Produce Powerful Microscopes and More

A non-twisting laser beam moving through magnetized plasma turns into an optical vortex that traps, rotates, and controls microscopic particles, opening new frontiers in imaging.

Whistling While You Work: Fusion Scientists Find Inspiration in Atmospheric Whistles

Just like lightning, fusion plasmas contain odd electromagnetic whistler waves that could control destructive electrons in fusion reactors.

Zero Tolerance in Tokamaks: Eliminating Small Instabilities Before They Become Disruptions

Energetic ions and beam heating cause or calm instabilities, depending on the tokamak's magnetic field.

MURR Becomes First Reactor Facility to Join DOE's Isotope Program

DOE and MURR partner to ensure scientists have access to essential research isotopes.


Spotlight

Monday May 07, 2018, 10:30 AM

Introducing Graduate Students Across the Globe to Photon Science

Brookhaven National Laboratory

Wednesday May 02, 2018, 04:05 PM

Students from Massachusetts and Washington Win DOE's 28th National Science Bowl(r)

Department of Energy, Office of Science

Thursday April 12, 2018, 07:05 PM

The Race for Young Scientific Minds

Argonne National Laboratory

Wednesday March 14, 2018, 02:05 PM

Q&A: Al Ashley Reflects on His Efforts to Diversify SLAC and Beyond

SLAC National Accelerator Laboratory

Thursday February 15, 2018, 12:05 PM

Insights on Innovation in Energy, Humanitarian Aid Highlight UVA Darden's Net Impact Week

University of Virginia Darden School of Business

Friday February 09, 2018, 11:05 AM

Ivy League Graduate, Writer and Activist with Dyslexia Visits CSUCI to Reframe the Concept of Learning Disabilities

California State University, Channel Islands

Wednesday January 17, 2018, 12:05 PM

Photographer Adam Nadel Selected as Fermilab's New Artist-in-Residence for 2018

Fermi National Accelerator Laboratory (Fermilab)

Wednesday January 17, 2018, 12:05 PM

Fermilab Computing Partners with Argonne, Local Schools for Hour of Code

Fermi National Accelerator Laboratory (Fermilab)

Wednesday December 20, 2017, 01:05 PM

Q&A: Sam Webb Teaches X-Ray Science from a Remote Classroom

SLAC National Accelerator Laboratory

Monday December 18, 2017, 01:05 PM

The Future of Today's Electric Power Systems

Rensselaer Polytechnic Institute (RPI)

Monday December 18, 2017, 12:05 PM

Supporting the Development of Offshore Wind Power Plants

Rensselaer Polytechnic Institute (RPI)

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)





Showing results

0-4 Of 2215