A Centauro event is a kind of anomalous event observed in cosmic-ray detectors since 1972. They are so named because their shape resembles that of a centaur: i.e., highly asymmetric.
In 1972, the Andean detector registered a cascade that was strangely rich in charged, quark-based particles; far more particles were detected in the bottom portion of the detector than in the top portion.
In years since, the detectors in Bolivia and Tajikistan have detected more than 40 Centauro events. Various explanations have been suggested. One possible explanation might be if the strong force between particles behaves unusually when they have extremely high energies.
Exploding black holes are also a possibility. The team calculated what signal a detector would register if a cosmic ray creates a miniature black hole that explodes nearby. The researchers' prediction is consistent with the observed Centauro events.
The Tomaras team hopes that computer simulations of mini-black holes exploding, and further observations, will solve the puzzle.
Solution to the Centauro puzzle
In 2003 an international team of researches from Russia and Japan found out that the mysterious observation from mountain-top cosmic ray experiments can be explained with conventional physics.
The new analysis of Centauro I reveals that there is a difference in the arrival angle between the upper block and lower block events, so the two are not products of the same interaction. That leaves only the lower chamber data connected to the Centauro I event. In other words, the man-horse analogy becomes redundant. There is only an obvious "tail", and no "head". The original detector setup had gaps between neighboring blocks in the upper chamber. Linear dimensions of gaps were comparable to the geometrical size of the event. The signal observed in the lower detector was similar to an ordinary interaction occurred at low altitude above the chamber, thus providing a natural solution: passing of a cascade of particles through a gap between the upper blocks.
In 2005 it was shown that "other Centauro events" can be explained by peculiarities of the Chacaltaya detector. So-called "exotic signal" observed so far in cosmic ray experiments using a traditional X-ray emulsion chamber detector can be consistently explained within the framework of standard physics.
Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter.
Cosmic rays are high-energy protons and atomic nuclei that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy, and from distant galaxies. Upon impact with Earth's atmosphere, cosmic rays produce showers of secondary particles, some of which reach the surface; although the bulk is intercepted by the magnetosphere or the heliosphere.
In astroparticle physics, an ultra-high-energy cosmic ray (UHECR) is a cosmic ray with an energy greater than 1 EeV (1018 electronvolts, approximately 0.16 joules), far beyond both the rest mass and energies typical of other cosmic ray particles.
Bruno Benedetto Rossi was an Italian experimental physicist. He made major contributions to particle physics and the study of cosmic rays. A 1927 graduate of the University of Bologna, he became interested in cosmic rays. To study them, he invented an improved electronic coincidence circuit, and travelled to Eritrea to conduct experiments that showed that cosmic ray intensity from the West was significantly larger than that from the East.
Neutrino astronomy is the branch of astronomy that observes astronomical objects with neutrino detectors in special observatories. Neutrinos are created as a result of certain types of radioactive decay, nuclear reactions such as those that take place in the Sun or high energy astrophysical phenomena, in nuclear reactors, or when cosmic rays hit atoms in the atmosphere. Neutrinos rarely interact with matter, meaning that it is unlikely for them to scatter along their trajectory, unlike photons. Therefore, neutrinos offer a unique opportunity to observe processes that are inaccessible to optical telescopes, such as reactions in the Sun's core. Neutrinos can also offer a very strong pointing direction compared to charged particle cosmic rays.
The Unruh effect is a kinematic prediction of quantum field theory that an accelerating observer will observe a thermal bath, like blackbody radiation, whereas an inertial observer would observe none. In other words, the background appears to be warm from an accelerating reference frame; in layman's terms, an accelerating thermometer in empty space, removing any other contribution to its temperature, will record a non-zero temperature, just from its acceleration. Heuristically, for a uniformly accelerating observer, the ground state of an inertial observer is seen as a mixed state in thermodynamic equilibrium with a non-zero temperature bath.
Micro black holes, also called quantum mechanical black holes or mini black holes, are hypothetical tiny black holes, for which quantum mechanical effects play an important role. The concept that black holes may exist that are smaller than stellar mass was introduced in 1971 by Stephen Hawking.
Exotic baryons are a type of hadron with half-integer spin, but have a quark content different from the three quarks (qqq) present in conventional baryons. An example would be pentaquarks, consisting of four quarks and one antiquark (qqqqq̅).
Strongly interacting massive particles (SIMPs) are hypothetical particles that interact strongly between themselves and weakly with ordinary matter, but could form the inferred dark matter despite this.
The Cryogenic Dark Matter Search (CDMS) is a series of experiments designed to directly detect particle dark matter in the form of Weakly Interacting Massive Particles. Using an array of semiconductor detectors at millikelvin temperatures, CDMS has at times set the most sensitive limits on the interactions of WIMP dark matter with terrestrial materials. The first experiment, CDMS I, was run in a tunnel under the Stanford University campus. It was followed by CDMS II experiment in the Soudan Mine. The most recent experiment, SuperCDMS, was located deep underground in the Soudan Mine in northern Minnesota and collected data from 2011 through 2015. The series of experiments continues with SuperCDMS SNOLAB, an experiment located at the SNOLAB facility near Sudbury, Ontario in Canada that started construction in 2018 and is expected to start data taking in early 2020s.
This is a timeline of subatomic particle discoveries, including all particles thus far discovered which appear to be elementary given the best available evidence. It also includes the discovery of composite particles and antiparticles that were of particular historical importance.
The IceCube Neutrino Observatory is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10). Its thousands of sensors are located under the Antarctic ice, distributed over a cubic kilometre.
Main injector neutrino oscillation search (MINOS) was a particle physics experiment designed to study the phenomena of neutrino oscillations, first discovered by a Super-Kamiokande (Super-K) experiment in 1998. Neutrinos produced by the NuMI beamline at Fermilab near Chicago are observed at two detectors, one very close to where the beam is produced, and another much larger detector 735 km away in northern Minnesota.
The XENON dark matter research project, operated at the Italian Gran Sasso National Laboratory, is a deep underground research facility featuring increasingly ambitious experiments aiming to detect dark matter particles. The experiments aim to detect particles in the form of weakly interacting massive particles (WIMPs) by looking for rare interactions via nuclear recoils in a liquid xenon target chamber. The current detector consists of a dual phase time projection chamber (TPC).
An exotic star is a hypothetical compact star composed of something other than electrons, protons, neutrons, or muons, and balanced against gravitational collapse by degeneracy pressure or other quantum properties. Exotic stars include quark stars and perhaps strange stars, as well as speculative preon stars. Of the various types of exotic star proposed, the most well evidenced and understood is the quark star.
The gravitational wave background is a random gravitational-wave signal potentially detectable by gravitational wave detection experiments. Since the background is supposed to be statistically random, it has yet been researched only in terms of such statistical descriptors as the mean, the variance, etc.
Gravitational-wave astronomy is an emerging branch of observational astronomy which aims to use gravitational waves to collect observational data about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.
Paul Buford Price, usually known as P. Buford Price, was a professor in the Graduate School at the University of California, Berkeley and a member of the National Academy of Sciences. His work had been wide-ranging over his career, but began with the study of physics and included cosmic rays, astrophysics, nuclear physics, glaciology, climatology, biology in extreme environments, and origins of life. He was born November 8, 1932 in Memphis, TN and died December 28, 2021.
A strangelet is a hypothetical particle consisting of a bound state of roughly equal numbers of up, down, and strange quarks. An equivalent description is that a strangelet is a small fragment of strange matter, small enough to be considered a particle. The size of an object composed of strange matter could, theoretically, range from a few femtometers across to arbitrarily large. Once the size becomes macroscopic, such an object is usually called a strange star. The term "strangelet" originates with Edward Farhi and Robert Jaffe in 1984. Strangelets can convert matter to strange matter on contact. Strangelets have been suggested as a dark matter candidate.
Primordial black hole (also abbreviated as PBH) is a hypothetical type of black hole that formed soon after the Big Bang. In the early universe, high densities and heterogeneous conditions could have led sufficiently dense regions to undergo gravitational collapse, forming black holes. Yakov Borisovich Zel'dovich and Igor Dmitriyevich Novikov in 1966 first proposed the existence of such black holes. The theory behind their origins was first studied in depth by Stephen Hawking in 1971. Since primordial black holes did not form from stellar gravitational collapse, their masses can be far below stellar mass (c. 2×1030 kg).
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
