We argue that extensions of the SM with a warped extra dimension, together with a new $${\mathbb {Z}}_2$$ Z 2-odd scalar singlet, provide a natural explanation not only for the hierarchy problem but also for the nature of fermion bulk masses and the observed dark matter relic abundance. In particular, the Kaluza-Klein excitations of the new scalar particle, which is required to naturally obtain fermion bulk masses through Yukawa-like interactions, can be the leading portal to any fermion propagating into the bulk of the extra dimension and playing the role of dark matter. Moreover, such scalar excitations will necessarily mix with the Higgs boson, leading to modifications of the Higgs couplings and branching ratios, and allowing the Higgs to mediate the coannihilation of the fermionic dark matter.
Chair emeritus, SETI institute — the search for extraterrestrial intelligence.
Dr. Jill Tarter is Chair Emeritus for SETI (Search for Extraterrestrial Intelligence) Research at the SETI Institute, a not-for-profit research organization whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to apply the knowledge gained to inspire and guide present and future generations.
Dr. Tarter received her Bachelor of Engineering Physics Degree with Distinction from Cornell University and her Master’s Degree and a Ph.D. in Astronomy from the University of California, Berkeley. She served as Project Scientist for NASA’s SETI program, the High Resolution Microwave Survey, and has conducted numerous observational programs at radio observatories worldwide. Since the termination of funding for NASA’s SETI program in 1993, she has served in a leadership role to secure private funding to continue the exploratory science. Currently, she serves on the management board for the Allen Telescope Array, an innovative array of 350 (when fully realized) 6-m antennas at the Hat Creek Radio Observatory, it will simultaneously survey the radio universe for known and unexpected sources of astrophysical emissions, and speed up the search for radio emissions from other distant technologies by orders of magnitude.
Dr. Tarter’s work has brought her wide recognition in the scientific community, including the Lifetime Achievement Award from Women in Aerospace, two Public Service Medals from NASA, Chabot Observatory’s Person of the Year award (1997), Women of Achievement Award in the Science and Technology category by the Women’s Fund and the San Jose Mercury News (1998), and the Tesla Award of Technology at the Telluride Tech Festival (2001). She was elected an AAAS Fellow in 2002 and a California Academy of Sciences Fellow in 2003. In 2004 Time Magazine named her one of the Time 100 most influential people in the world, and in 2005 Dr. Tarter was awarded the Carl Sagan Prize for Science Popularization at Wonderfest, the biannual San Francisco Bay Area Festival of Science.
Dr. Tarter is deeply involved in the education of future citizens and scientists. In addition to her scientific leadership at NASA and SETI Institute, Dr. Tarter was the Principal Investigator for two curriculum development projects funded by NSF, NASA, and others. The first, the Life in the Universe series, created 6 science teaching guides for grades 3–9 (published 1994–96). Her second project, Voyages Through Time, is an integrated high school science curriculum on the fundamental theme of evolution in six modules: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution and Evolution of Technology (published 2003).
Dr. Tarter is a frequent speaker for science teacher meetings and at museums and science centers, bringing her commitment to science and education to both teachers and the public.
Many people are now familiar with her work as portrayed by Jodie Foster in the movie Contact. She is also the subject of the book, Making Contact: Jill Tarter and the Search for Extraterrestrial Intelligence.
Scientists have discovered the first evidence for a rare type of stellar explosion, or supernova in the Milky Way. This intriguing object lies near the center of our galaxy in a supernova remnant called Sagittarius A East (Sgr A East). Chandra data revealed that Sgr A East may belong to a spec.
Eventually, galaxies stop making new stars. But why did some stop so much sooner than others? Hint: black holes play a role.
A galaxy’s main business is star formation. And when they’re young, like youth everywhere, they keep themselves busy with it. But galaxies age, evolve, and experience a slow-down in their rate of star formation. Eventually, galaxies cease forming new stars altogether, and astronomers call that quenching. They’ve been studying quenching for decades, yet much about it remains a mystery.
A new study based on the IllustrisTNG simulations has found a link between a galaxy’s quenching and its stellar size.
Scientists are finally figuring out how much dark matter — the almost imperceptible material said to tug on everything, yet emit no light — really weighs.
Astronomy owes George Ellery Hale and the Palomar Observatory a great debt of gratitude for persevering with the construction of a telescope that forever changed cosmology.
BASE opens up new possibilities in the search for cold dark matter.
The Baryon Antibaryon Symmetry Experiment (BASE) at CERN’s Antimatter Factory has set new limits on how easily axion-like particles in a narrow mass range around 2.97 neV can turn into photons, the particles of light. BASE’s new result, published by Physical Review Letters, describes this pioneering method and opens up new experimental possibilities in the search for cold dark matter.
Axions, or axion-like particles, are candidates for cold dark matter. From astrophysical observations, we believe that around 27% of the matter-energy content of the universe is made up of dark matter. These unknown particles feel the force of gravity, but they barely respond to the other fundamental forces, if they experience them at all. The best accepted theory of fundamental forces and particles, called the Standard Model of particle physics, does not contain any particles that have the right properties to be cold dark matter.
Since the Standard Model leaves many questions unanswered, physicists have proposed theories that go beyond it, some of which explain the nature of dark matter. Among such theories are those that suggest the existence of axions or axion-like particles. These theories need to be tested, and many experiments have been set up around the world to look for these particles, including at CERN. For the first time, BASE has turned the tools developed to detect single antiprotons, the antimatter equivalent of a proton, to the search for dark matter. This is especially significant as BASE was not designed for such studies.
“BASE has extremely sensitive detection systems to study the properties of single trapped antiprotons. These detectors can also be used to search for signals of particles other than those produced by antiprotons in traps. In this work, we used one of our detectors as an antenna to search for a new type of axion-like particles,” says Jack Devlin, a CERN research fellow working on the experiment.
Compared to the large detectors installed in the Large Hadron Collider (LHC), BASE is a small experiment. It is connected to CERN’s Antiproton Decelerator, which supplies it with antiprotons. BASE captures and suspends these particles in a Penning trap, a device that combines electric and strong magnetic fields. To avoid collisions with ordinary matter, the trap is operated at 5 kelvins (around-268 degrees Celsius), a temperature at which exceedingly low pressures, similar to those in deep space, are reached. In this extremely well-isolated environment, clouds of trapped antiprotons can exist for years at a time. By carefully adjusting the electric fields, the physicists at BASE can isolate individual antiprotons and move them to a separate part of the experiment. In this region, very sensitive superconducting resonant detectors can pick up the tiny electrical currents generated by single antiprotons as they move around the trap.
I don’t think that star is the same after that one night stand.
When black holes swallow down massive amounts of matter from the space around them, they’re not exactly subtle about it. They belch out tremendous flares of X-rays, generated by the material heating to intense temperatures as it’s sucked towards the black hole, so bright we can detect them from Earth.
This is normal black hole behaviour. What isn’t normal is for those X-ray flares to spew forth with clockwork regularity, a puzzling behaviour reported in 2019 from a supermassive black hole at the centre of a galaxy 250 million light-years away. Every nine hours, boom — X-ray flare.
After careful study, astronomer Andrew King of the University of Leicester in the UK identified a potential cause — a dead star that’s endured its brush with a black hole, trapped on a nine-hour, elliptical orbit around it. Every close pass, or periastron, the black hole slurps up more of the star’s material.
