Research Highlights
James Webb Space Telescope Looks Within for Dark Matter
Since its launch in 2021, the JWST has observed not just galaxies at the edge of the visible Universe but also our nearest stellar neighbor, Proxima Centauri. Now Peizhi Du at the University of Science and Technology of China, formerly a postdoctoral researcher at Stony Brook, as well as Stony Brook Professor Rouven Essig and his recent graduate student Hailin Xu, and NASA scientist Bernie Rauscher, have used the JWST to look for objects that are even closer. By analyzing ostensibly blank calibration images, the team sought signs of dark matter within the telescope itself. Finding none, the researchers put constraints on the existence of dark matter that interacts strongly with ordinary matter.
The team considered one proposed type of dark matter that interacts with electrically charged particles. The strength of this interaction is orders of magnitude feebler than that of electromagnetism but is still sufficiently large that it would hinder the particles’ passage through Earth’s atmosphere. Such dark matter is therefore expected to be especially hard to spot using typical ground-based experiments. Instead, space-based instruments offer a promising alternative.
The team analyzed images acquired when JWST’s near-infrared spectrograph was covered. These images were obtained so that researchers could characterize the instrument’s noise. Even so, although the sensor was protected from external photons, pixels could still record cosmic rays and internally generated radiation. Du and colleagues filtered out those events in the hope of finding a residual signal caused by strongly interacting dark matter. The absence of such a signal implies that this form of dark matter contributes no more than 0.4% to the Universe’s total.
This work was published in PRL, selected as an Editor's Suggestion and featured in Physics.
Stony Brook Simulations Help Explain Lightning’s Mysterious Origins
A recent study in Nature Physics reveals how ordinary ice can generate electricity, providing crucial insight into the origins of lightning. It was discovered that ice exhibits strong flexoelectricity—an electromechanical effect that occurs when the material is bent.
At Stony Brook University, PhD student Anthony Mannino, working under the supervision of Professor Marivi Fernandez-Serra in the Department of Physics & Astronomy and the Core Faculty at the Institute for Advanced Computational Science (IACS), spearheaded the theoretical side of the project.
The international collaboration was led experimentally by Professor Gustau Catalan and Dr. Xin Wen at the Institut Català de Nanociència i Nanotecnologia (ICN2) in Barcelona.
Using the Seawulf supercomputing cluster, Mannino performed large-scale quantum simulations that revealed how the surface of ice can undergo subtle ferroelectric ordering at low temperatures. This ordering amplifies the flexoelectric effect and explains how collisions between ice particles and graupel in thunderclouds can generate the massive charge separations that lead to lightning.
“Helping to facilitate an innovative discovery like the origin of lightning is exciting, extremely rewarding, and very much in keeping with the fundamental role of computation in contemporary science,” said Professor in the Department of Physics and Astronomy and Deputy Director of the Institute for Advanced Computational Science (IACS) Alan Calder. “As this study shows, with the combination of clever investigators and advanced computing the sky, or lightning shooting through it at least, is literally the limit.”
First Physics Results from the sPHENIX Particle Detector
The sPHENIX particle detector, the newest experiment at the Relativistic Heavy Ion Collider (RHIC) at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, has released its first physics results: precision measurements of the number and energy density of thousands of particles streaming from collisions of near-light-speed gold ions. As described in two papers recently accepted for publication in Physical Review C and the Journal of High Energy Physics, these measurements lay the foundation for the detector’s detailed exploration of the quark-gluon plasma (QGP), a unique state of matter that existed just microseconds after the Big Bang some 14 billion years ago.
The new measurements reveal that the more head-on the nuclear smashups are, the more charged particles they produce and the more total energy those firework-like sprays of particles carry. That matches nicely with results from other detectors that have tracked QGP-generating collisions at RHIC since 2000, confirming that the new detector is performing as promised.
“As a new and highly sophisticated experiment that has gone through a decade of planning, construction, and commissioning, the first questions we need to ask are: Is the detector operating properly, is our calibration accurate, and are our data-processing pipelines reliable?” said Jin Huang, a physicist at Brookhaven Lab and co-spokesperson for the sPHENIX Collaboration. “The best way to do that is to go through measurements of the fundamental collision properties and confirm that the detector is measuring them properly.”
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