Scientists tracked a neutrino back to a violent black hole — and it could help explain where elusive cosmic rays originate.
Category: particle physics – Page 307
An international research team led by the University of Würzburg and the University of Geneva (UNIGE) is shedding light on one aspect of this mystery: neutrinos are thought to be born in blazars, galactic nuclei fed by supermassive black holes.
Sara Buson has always thought of it as a significant task. In 2017, the researcher and his associates introduced a blazar (TXS 0506+056) as a potential neutrino source for the first time. That study sparked a scientific debate about whether there truly is a connection between blazars and high-energy neutrinos.
After taking this initial, positive step, Prof. Buson’s team received funding from the European Research Council to launch an ambitious multi-messenger research project in June 2021. Analyzing numerous signals (or “messengers,” for example, neutrinos) from the Universe is required. The primary objective is to shed light on the origin of astrophysical neutrinos, potentially confirming blazars as the first highly certain source of high-energy extragalactic neutrinos.
Scientists have found three new examples of a very exotic form of matter made of quarks. They can yield insights into the early Universe.
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Should the Fed make a 1-percentage-point hike at the July meeting, it would be the largest move since Paul Volcker was Fed chairman in the 1980s.
Lasers normally use mirrors to create laser light, but a new kind uses clumps of moving particles. The result is a laser that is more programmable and could generate extra-sharp visual displays.
A team of researchers from IBM Research Europe, Universidade de Santiago de Compostela and the University of Regensburg has changed the bonds between the atoms in a single molecule for the first time. In their paper published in the journal Science, the group describes their method and possible uses for it. Igor Alabugin and Chaowei Hu, have published a Perspective piece in the same journal issue outlining the work done by the team.
The current method for creating complex molecules or molecular devices, as Alagugin and Chaowei note, is generally quite challenging—they liken it to dumping a box of Legos in a washing machine and hoping that some useful connections are made. In this new effort, the research team has made such work considerably easier by using a scanning tunneling microscope (STM) to break the bonds in a molecule and then to customize the molecule by creating new bonds—a chemistry first.
The work by the team involved placing a sample material into a scanning tunneling microscope and then using a very tiny amount of electricity to break specific bonds. More specifically, they began by pulling four chlorine atoms from the core of a tetracyclic to use as their starting molecule. They then moved the tip of the STM to a C-CI bond and then broke the bond with a jolt of electricity. Doing so to the other C-CI and C-C pairs resulted in the formation of a diradical, which left six electrons free for use in forming other bonds. In one test of creating a new molecule, the team then used the free electrons (and a dose of high voltage) to form diagonal C-C bonds, resulting in the creation of a bent alkyne. In another example, they applied a dose of low voltage to create a cyclobutadiene ring.
The quantum vibrations in atoms hold a miniature world of information. If scientists can accurately measure these atomic oscillations, and how they evolve over time, they can hone the precision of atomic clocks as well as quantum sensors, which are systems of atoms whose fluctuations can indicate the presence of dark matter, a passing gravitational wave, or even new, unexpected phenomena.
A major hurdle in the path toward better quantum measurements is noise from the classical world, which can easily overwhelm subtle atomic vibrations, making any changes to those vibrations devilishly hard to detect.
Now, MIT physicists have shown they can significantly amplify quantum changes in atomic vibrations, by putting the particles through two key processes: quantum entanglement and time reversal.
A curious thing happened when MIT researchers Adam Vernon and Ronald Garcia Ruiz, along an international team of scientists, recently performed an experiment in which a sensitive laser spectroscopy technique was used to measure how the nuclear electromagnetic properties of indium isotopes evolve when an extreme number of neutrons are added to the nucleus. These nuclei do not exist in nature, and once created, their lifetimes can be as short as a fraction of a second, so the team artificially created the nuclei using a particle accelerator at the CERN research facility in Switzerland. By using a combination of multiple lasers and an ion trap, the team isolated the isotopes of interest and performed precision measurements of atoms containing these exotic nuclei. In turn, it allowed the extraction of their nuclear properties.
Vernon, a postdoc in the Laboratory for Nuclear Science (LNS); Garcia Ruiz, an assistant professor of physics and LNS affiliate; and their colleagues achieved a surprising result. When measuring a nucleus with a certain “magic” number of neutrons—82—the magnetic field of the nucleus exhibited a drastic change, and the properties of these very complex nuclei appear to be governed by just one of the protons of the nucleus.
“The new observation at 82 total neutrons changes this picture of the nucleus. We had to come up with new nuclear theories to explain the result,” says Vernon.
Lasers normally use mirrors to create laser light, but a new kind uses clumps of moving particles. The result is a laser that is more programmable and could generate extra-sharp visual displays.
TRISO particles cannot melt in a reactor and can withstand extreme temperatures well beyond the threshold of current nuclear fuels.
There’s a lot of buzz around advanced nuclear.
These technologies are going to completely change the way we think about nuclear reactors.
More than 70 projects are underway in the United States with new designs that are expected to be more economical to build and operate.
After the Higgs, the Large Hadron Collider was expected to find other theorised particles. It didn’t, but particle physicists are optimistic about a new era of experiment-led exploration.