<address id="9fb5l"></address>

        . 24/7 Space News .




        Subscribe to our free daily newsletters



        TIME AND SPACE
        New calculation refines comparison of matter with antimatter
        by Staff Writers
        Upton NY (SPX) Sep 18, 2020

        A new calculation performed using the world's fastest supercomputers allows scientists to more accurately predict the likelihood of two kaon decay pathways, and compare those predictions with experimental measurements. The comparison tests for tiny differences between matter and antimatter that could, with even more computing power and other refinements, point to physics phenomena not explained by the Standard Model.

        An international collaboration of theoretical physicists - including scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory (BNL) and the RIKEN-BNL Research Center (RBRC) - has published a new calculation relevant to the search for an explanation of the predominance of matter over antimatter in our universe. The collaboration, known as RBC-UKQCD, also includes scientists from CERN (the European particle physics laboratory), Columbia University, the University of Connecticut, the University of Edinburgh, the Massachusetts Institute of Technology, the University of Regensburg, and the University of Southampton. They describe their result in a paper to be published in the journal Physical Review D and has been highlighted as an "editor's suggestion."

        Scientists first observed a slight difference in the behavior of matter and antimatter - known as a violation of "CP symmetry" - while studying the decays of subatomic particles called kaons in a Nobel Prize winning experiment at Brookhaven Lab in 1963. While the Standard Model of particle physics was pieced together soon after that, understanding whether the observed CP violation in kaon decays agreed with the Standard Model has proved elusive due to the complexity of the required calculations.

        The new calculation gives a more accurate prediction for the likelihood with which kaons decay into a pair of electrically charged pions vs. a pair of neutral pions. Understanding these decays and comparing the prediction with more recent state-of-the-art experimental measurements made at CERN and DOE's Fermi National Accelerator Laboratory gives scientists a way to test for tiny differences between matter and antimatter, and search for effects that cannot be explained by the Standard Model.

        The new calculation represents a significant improvement over the group's previous result, published in Physical Review Letters in 2015. Based on the Standard Model, it gives a range of values for what is called "direct CP symmetry violation" in kaon decays that is consistent with the experimentally measured results.

        That means the observed CP violation is now, to the best of our knowledge, explained by the Standard Model, but the uncertainty in the prediction needs to be further improved since there is also an opportunity to reveal any sources of matter/antimatter asymmetry lying beyond the current theory's description of our world.

        "An even more accurate theoretical calculation of the Standard Model may yet lie outside of the experimentally measured range. It is therefore of great importance that we continue our progress, and refine our calculations, so that we can provide an even stronger test of our fundamental understanding," said Brookhaven Lab theorist Amarjit Soni.

        Matter/antimatter imbalance
        "The need for a difference between matter and antimatter is built into the modern theory of the cosmos," said Norman Christ of Columbia University.

        "Our current understanding is that the present universe was created with nearly equal amounts of matter and antimatter. Except for the tiny effects being studied here, matter and antimatter should be identical in every way, beyond conventional choices such as assigning negative charge to one particle and positive charge to its anti-particle. Some difference in how these two types of particles operate must have tipped the balance to favor matter over antimatter," he said.

        "Any differences in matter and antimatter that have been observed to date are far too weak to explain the predominance of matter found in our current universe," he continued. "Finding a significant discrepancy between an experimental observation and predictions based on the Standard Model would potentially point the way to new mechanisms of particle interactions that lie beyond our current understanding - and which we hope to find to help to explain this imbalance."

        Modeling quark interactions
        All of the experiments that show a difference between matter and antimatter involve particles made of quarks, the subatomic building blocks that bind through the strong force to form protons, neutrons, and atomic nuclei - and also less-familiar particles like kaons and pions.

        "Each kaon and pion is made of a quark and an antiquark, surrounded by a cloud of virtual quark-antiquark pairs, and bound together by force carriers called gluons," explained Christopher Kelly, of Brookhaven National Laboratory.

        The Standard Model-based calculations of how these particles behave must therefore include all the possible interactions of the quarks and gluons, as described by the modern theory of strong interactions, known as quantum chromodynamics (QCD).

        In addition, these bound particles move at close to the speed of light. That means the calculations must also include the principles of relativity and quantum theory, which govern such near-light-speed particle interactions.

        "Because of the huge number of variables involved, these are some of the most complicated calculations in all of physics," noted Tianle Wang, of Columbia University.

        Computational challenge
        To conquer the challenge, the theorists used a computing approach called lattice QCD, which "places" the particles on a four-dimensional space-time lattice (three spatial dimensions plus time). This box-like lattice allows them to map out all the possible quantum paths for the initial kaon to decay to the final two pions. The result becomes more accurate as the number of lattice points increases. Wang noted that the "Feynman integral" for the calculation reported here involved integrating 67 million variables!

        These complex calculations were done by using cutting-edge supercomputers. The first part of the work, generating samples or snapshots of the most likely quark and gluon fields, was performed on supercomputers located in the US, Japan, and the UK. The second and most complex step of extracting the actual kaon decay amplitudes was performed at the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science user facility at DOE's Lawrence Berkeley National Laboratory.

        But using the fastest computers is not enough; these calculations are still only possible even on these computers when using highly optimized computer codes, developed for the calculation by the authors.

        "The precision of our results cannot be increased significantly by simply performing more calculations," Kelly said. "Instead, in order to tighten our test of the Standard Model we must now overcome a number of more fundamental theoretical challenges. Our collaboration has already made significant strides in resolving these issues and coupled with improvements in computational techniques and the power of near-future DOE supercomputers, we expect to achieve much improved results within the next three to five years."

        Research Report:


        Related Links
        Brookhaven National Laboratory
        Understanding Time and Space


        Thanks for being there;
        We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

        With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

        Our news coverage takes time and effort to publish 365 days a year.

        If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
        SpaceDaily Monthly Supporter
        $5+ Billed Monthly


        paypal only
        SpaceDaily Contributor
        $5 Billed Once


        credit card or paypal


        TIME AND SPACE
        Large Hadron Collider upgrade to be led by Manchester scientists
        Manchester UK (SPX) Sep 14, 2020
        Scientists, engineers and technicians from The University of Manchester, along with other UK research organisations, have embarked on a Pounds 26M project to help upgrade the Large Hadron Collider (LHC) at CERN, on the French/Swiss border near Geneva. CERN's High Luminosity LHC project (HL-LHC), a large international collaboration, will upgrade the LHC by increasing the number of particle collisions by a factor of 10, allowing physicists to learn more about the properties of the Higgs Boson and l ... read more

        Comment using your Disqus, Facebook, Google or Twitter login.



        Share this article via these popular social media networks
        del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

        TIME AND SPACE
        NASA's Partnership Between Art and Science: A Collaboration to Cherish

        Israeli tech start-ups take on the Emirates

        ISS may need to evade US Military cubesat

        NASA Goddard's first virtual interns reflect on their summer experience

        TIME AND SPACE
        Air Force destroys surrogate cruise missile in hypervelocity projectile test

        China's launch of new satellite fails

        UK Spaceports form historic alliance

        Northrop Grumman and NASA donate Shuttle boosters to California Science Center

        TIME AND SPACE
        Using chitin to manufacture tools and shelters on Mars

        Study shows difficulty in finding evidence of life on Mars

        China's Mars probe travels 137 mln km

        ERC Space and Robotics Event 2020

        TIME AND SPACE
        China sends nine satellites into orbit by sea launch

        Chinese spacecraft launched mystery object into space before returning to Earth

        China's reusable spacecraft returns to Earth after 2 days

        Mars-bound Tianwen 1 hits milestone

        TIME AND SPACE
        Dragonfly Aerospace emerges from SCS Aerospace Group

        COMSAT expands hardware footprint with new Orbit Communications Systems agreement

        Wanted: your ideas for ESA's future space missions

        GMV announces the merger of its UK Company and NSL

        TIME AND SPACE
        Zombie satellites and rogue debris threatening existence of ISS

        Making waves in space

        Government backs UK companies tackling dangerous 'space junk'

        Earth's Van Allen radiation belts double as particle accelerator

        TIME AND SPACE
        A white dwarf's surprise planetary companion

        Scientists find gas on Venus linked to life on Earth

        How protoplanetary rings form in primordial gas clouds

        NASA missions spy first possible survivor planet hugging white dwarf star

        TIME AND SPACE
        Jupiter's moons could be warming each other

        Astronomers characterize Uranian moons using new imaging analysis

        Atomistic modelling probes the behavior of matter at the center of Jupiter

        Technology ready to explore subsurface oceans on Ganymede













        The content herein, unless otherwise known to be public domain, are Copyright 1995-2021 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.


        一晚破了3个处