Scientists are using trapped ions in cutting-edge experiments to hunt for signs of an undiscovered particle that might help unravel the mystery of dark matter.
The Standard Model of particle physics offers an exceptionally precise description of the fundamental components that form all visible matter, including the particles that make up everything around us and ourselves. It also defines the basic forces that govern interactions between these elementary particles.
“The Standard Model is currently the best explanation of the universe, but we know it cannot explain everything,” says Diana Prado Lopes Aude Craik, Physics Professor at ETH Zurich. She points to dark matter as an example of “one of the biggest mysteries in physics today.”
Observations from astronomy indicate that the visible matter we can detect does not fully account for the way galaxies spin. Because of this, physicists believe that the majority of the universe’s mass is made up of an unknown type of matter. This has led to a search for theories that can extend beyond what the Standard Model currently explains.
Among the leading ideas are theories that propose a new, fifth force of nature to accompany the four known fundamental forces: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. One possibility is that a previously unknown force exists between neutrons in the atomic nucleus and electrons in the surrounding electron cloud. This hypothetical force might be transmitted by a new particle, in a manner similar to how photons are responsible for carrying the electromagnetic force.
Measuring the atom with precision
Researchers have long conducted experiments using particle accelerators, such as at CERN in Geneva, to search for new particles beyond the Standard Model. Aude Craik and her colleagues in Professor Jonathan Home’s research group at the ETH Institute of Quantum Electronics are taking a different approach.
“As atomic physicists, we can measure the atom with extremely high precision,” she explains. “Therefore, the idea is to search for this new force between the neutron and the electron using precision atomic spectroscopy.” The Zurich-based team is collaborating with research groups in Germany and Australia on this project.
“If this force really exists in the atom, then its strength is proportional to the number of neutrons in the atomic nucleus,” explains Luca Huber, a doctoral student in the research team. “That’s why we are experimenting with isotopes to detect this hypothetical force.”
Isotopes are types of the same atom that differ only in the number of neutrons in the atomic nucleus. This means that isotopes have the same number of protons and electrons and are therefore chemically identical, but they each have different masses.
As a result, the total force experienced by the electrons in different isotopes should vary slightly due to the different number of neutrons. This can be measured by examining the energy levels on which the electrons move within the atom. Specifically, researchers expect the new force to cause slight shifts in the energy levels between different isotopes.
Studying calcium isotopes in a precision ion trap
“To determine these energy shifts, we measure the frequency of the light emitted when our isotopes transition between two energy levels,” explains Aude Craik.
This measurement requires an ion trap, where electromagnetic fields hold a single charged isotope in place and a laser excites it to a higher energy state. Specifically, the researchers used five stable, singly-charged calcium isotopes in their experiments. Each isotope contained 20 protons, but the number of neutrons ranged from 20 to 28. In the laboratory, the researchers were able to determine the shifts in energy levels of these isotopes with an accuracy of 100 millihertz, which is one hundred times more precise than the best previous measurements. But how did they achieve this?
“We trapped two isotopes at the same time in the ion trap and measured them together,” explains Huber. This allowed them to drastically reduce the interfering noise during the frequency measurement.
However, despite this precision, further experiments were needed to advance the search for new physics. While the team in Zurich experimented with singly charged calcium isotopes, a research group led by Piet Schmidt at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig used the same isotopes but in a multiply charged state.
The German group measured a different transition in these highly charged calcium ions with similar accuracy to the Zurich team. A third group, led by Klaus Blaum at the Max Planck Institute for Nuclear Physics in Heidelberg, measured the ratios of nuclear masses between these isotopes with extreme precision.
More precise constraints determined
To interpret this result correctly, other research teams in Germany and Australia carried out precision calculations. Their results show that well-understood nuclear effects explain only part of the deviation. Another possible cause is nuclear polarization, a type of deformation of the atomic nucleus caused by electrons, which has been little studied so far. Its complex calculation shows that nuclear polarization could be large enough to explain the measured nonlinearity within the limits of the Standard Model.
“We can’t say that we’ve discovered new physics here,” emphasizes Aude Craik. “However, we know how strong the new force can be at most because we would have seen it otherwise in our measurements, even with the uncertainties”. The researchers can now set bounds on the possible values for the mass and charge of the hypothetical particle that would transmit this new force.
The researchers are now working to further improve the accuracy of their results. “We are currently measuring a third energy transition in the calcium isotopes,” says Huber, “and doing so with even greater precision than before.” With this, they aim to expand the King plot from two dimensions into a three-dimensional diagram. “We hope that this will help us overcome the theoretical challenges and make further progress in the search for this new force,” says Aude Craik.
Website: International Research Awards on High Energy Physics and Computational Science.
#HighEnergyPhysics#ParticlePhysics#QuantumPhysics#AstroparticlePhysics#ColliderPhysics#HiggsBoson#LHC#QuantumFieldTheory#NeutrinoPhysics#PhysicsResearch#ComputationalScience#DataScience#ScientificComputing#NumericalMethods#HighPerformanceComputing#MachineLearningInScience#BigData#AlgorithmDevelopment#SimulationScience#ParallelComputing
Visit Our Website : hep-conferences.sciencefather.com
Nomination Link :hep-conferences.sciencefather.com/award-nomination/?ecategory=Awards&rcategory=Awardee
Registration Link : hep-conferences.sciencefather.com/award-registration/
Member Link : hep-conferences.sciencefather.com/conference-membership/?ecategory=Membership&rcategory=Member
Awards-Winners : hep-conferences.sciencefather.com/awards-winners/
For Enquiries: physicsqueries@sciencefather.com
Get Connected Here:
==================
Social Media Link
Twitter : x.com/Psciencefather
Pinterest : in.pinterest.com/physicsresearchorganisation
Blog : physicscience23.blogspot.com
Instagram : www.instagram.com/victoriaanisa1
YouTube :www.youtube.com/channel/UCzqmZ9z40uRjiPSr9XdEwMA
Tumblr : https://www.tumblr.com/blog/hepcs
Share
Comments
Post a Comment