Hubble image of the spiral galaxy NGC 1068. Credit: NASA/ESA/A. van der Hoeven

Posted on November 3, 2022 by Staff

The detection was made at the National Science Foundation-supported IceCube Neutrino Observatory, a massive neutrino telescope encompassing 1 billion tons of instrumented ice at depths of 1.5 to 2.5 kilometers below Antarctica’s surface near the South Pole. This unique telescope, which explores the farthest reaches of our universe using neutrinos, reported the first observation of a high-energy astrophysical neutrino source in 2018. The source, TXS 0506+056, is a known blazar located off the left shoulder of the Orion constellation and 4 billion light-years away.

“One neutrino can single out a source. But only an observation with multiple neutrinos will reveal the obscured core of the most energetic cosmic objects,” says Francis Halzen, a professor of physics at the University of Wisconsin–Madison and principal investigator of IceCube. He adds, “IceCube has accumulated some 80 neutrinos of teraelectronvolt energy from NGC 1068, which are not yet enough to answer all our questions, but they definitely are the next big step towards the realization of neutrino astronomy.”

Unlike light, neutrinos can escape in large numbers from extremely dense environments in the universe and reach Earth largely undisturbed by matter and the electromagnetic fields that permeate extragalactic space. Although scientists envisioned neutrino astronomy more than 60 years ago, the weak interaction of neutrinos with matter and radiation makes their detection extremely difficult. Neutrinos could be key to our queries about the workings of the most extreme objects in the cosmos.

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An artist's impression of a gamma-ray burst. (ESO/A. Roquette)

12 October 2022
By MICHELLE STARR

Observatories around the world have just detected a colossal flare of extremely energetic radiation described as "record-breaking".

The event, first detected on October 9, was so bright that it was initially confused for an event closer to home. Initially dubbed Swift J1913.1+1946, it was thought to be a brief flash of X-rays from a not-too-distant source. It was only through further analysis that astronomers discovered the true nature of the glow – a gamma-ray burst, one of the most violent explosions in the Universe, now re-named GRB221009A.

Though further away, it was still one of the closest seen yet, just 2.4 billion light-years away. Moreover, this exceptionally bright gamma-ray burst appears to be the most energetic ever detected, coming in at up to 18 teraelectronvolts.

To be clear, though this proximity happens to be 20 times closer than the average long gamma-ray burst, it poses absolutely no danger to life on Earth.

Rather, it's tremendously exciting – an event that could shed new light (pun intended) on these fascinating explosions. Although its closeness makes it appear brighter in our sky, GRB221009A is possibly the most intrinsically bright gamma-ray burst we've ever seen.

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Computer reconstruction of a collision event in the Large Hadron Collider beauty experiment. The collision produces a B meson, which subsequently decays into other particles that strike LHCb’s detectors.  CERN/LHCb

Charlie Wood -- May 26, 2020

Amid the chaotic chains of events that ensue when protons smash together at the Large Hadron Collider in Europe, one particle has popped up that appears to go to pieces in a peculiar way.

All eyes are on the B meson, a yoked pair of quark particles. Having caught whiffs of unexpected B meson behavior before, researchers with the Large Hadron Collider beauty experiment (LHCb) have spent years documenting rare collision events featuring the particles, in hopes of conclusively proving that some novel fundamental particle or effect is meddling with them.

In their latest analysis, first presented at a seminar in March, the LHCb physicists found that several measurements involving the decay of B mesons conflict slightly with the predictions of the Standard Model of particle physics — the reigning set of equations describing the subatomic world. Taken alone, each oddity looks like a statistical fluctuation, and they may all evaporate with additional data, as has happened before. But their collective drift suggests that the aberrations may be breadcrumbs leading beyond the Standard Model to a more complete theory.

“For the first time in certainly my working life, there are a confluence of different decays that are showing anomalies that match up,” said Mitesh Patel, a particle physicist at Imperial College London who is part of LHCb.

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The NuSTAR telescope is sensitive to the high-energy X-rays that would provide stronger evidence for the existence of axions.
NASA/JPL-Caltech

Jonathan O'Callaghan  -  October 19, 2021

Approximately 85% of the mass in the universe is missing — we can infer its existence, we just can’t see it. Over the years, a number of different explanations for this “dark matter” have been proposed, from undiscovered particles to black holes. One idea in particular, however, is drawing renewed attention: the axion. And researchers are turning to the skies to track it down.

Axions are hypothetical lightweight particles whose existence would resolve two major problems. The first, fussed over since the 1960s, is the strong charge-parity (CP) problem, which asks why the quarks and gluons that make up protons and neutrons obey a certain symmetry. Axions would show that an unseen field is responsible.

The second is dark matter. Axions “are excellent dark matter candidates,” said Asimina Arvanitaki, a theoretical physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada. Axions would clump together in exactly the ways we expect dark matter to, and they have just the right properties to explain why they’re so hard to find — namely, they’re extremely light and reluctant to interact with regular matter.

Earlier this year, a group of scientists reported that they might have spotted evidence of axions being produced by neutron stars — collapsed stars that are so dense, a tiny sample little bigger than a grain of sand would weigh as much as an aircraft carrier. Ever since the 1980s, physicists have thought that if axions do exist, they should be produced inside the hot cores of neutron stars, where neutrons and protons smash together at high energies.

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Fourteen celestial sources of gamma rays (colored dots in this all-sky map of the Milky Way; yellow indicates bright sources and blue shows dim sources) may come from stars made of antimatter. SIMON DUPOURQUÉ/IRAP

If true, the preliminary find might mean some antimatter survived to the present day

By Maria Temming
APRIL 26, 2021

Fourteen pinpricks of light on a gamma-ray map of the sky could fit the bill for antistars, stars made of antimatter, a new study suggests.

These antistar candidates seem to give off the kind of gamma rays that are produced when antimatter — matter’s oppositely charged counterpart — meets normal matter and annihilates. This could happen on the surfaces of antistars as their gravity draws in normal matter from interstellar space, researchers report online April 20 in Physical Review D.

“If, by any chance, one can prove the existence of the antistars … that would be a major blow for the standard cosmological model,” says Pierre Salati, a theoretical astrophysicist at the Annecy-le-Vieux Laboratory of Theoretical Physics in France not involved in the work. It “would really imply a significant change in our understanding of what happened in the early universe.”

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The storage-ring magnet used for the g – 2 experiment at Fermilab.Credit: Reidar Hahn/Fermilab

30 March 2021

 Long-awaited muon physics experiment nears moment of truth

A result that has been 20 years in the making could reveal the existence of new particles, and upend fundamental physics.

After a two-decade wait that included a long struggle for funding and a move halfway across a continent, a rebooted experiment on the muon — a particle similar to the electron but heavier and unstable — is about to unveil its results. Physicists have high hopes that its latest measurement of the muon’s magnetism, scheduled to be released on 7 April, will uphold earlier findings that could lead to the discovery of new particles.

The Muon g – 2 experiment, now based at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, first ran between 1997 and 2001 at Brookhaven National Laboratory on Long Island, New York. The original results, announced in 2001 and then finalized in 20061, found that the muon’s magnetic moment — a measure of the magnetic field it generates — is slightly larger than theory predicted. This caused a sensation, and spurred controversy, among physicists. If those results are ultimately confirmed — in next week’s announcement, or by future experiments — they could reveal the existence of new elementary particles and upend fundamental physics. “Everybody’s antsy,” says Aida El-Khadra, a theoretical physicist at the University of Illinois at Urbana-Champaign.

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The Large Hadron Collider at Cern, where scientists are studying the decay of a subatomic particle known as the ‘beauty quark’
(EPA)

23.3.2021

Harry Cockburn : INDEPENDENT

Scientists ‘cautiously excited’ as experiment points towards new era in our understanding of the universe

Unexpected behaviour of subatomic particle known as the ‘beauty quark’ turns standard model of particle physics on its head

Scientists studying the fundamental forces which govern the universe and everything in it are “cautiously excited” recent experiments could lead to a “new era” in our understanding of physics.

While much scientific experimentation confirms existing hypothesis, it seems what gets scientists really bursting with enthusiasm is the discovery of something which confounds their existing theories.

This is what has happened following recent work by an international team conducting a study on subatomic particles at the Large Hadron Collider (LHC) at CERN, the European Organisation for Nuclear Research, near Geneva in Switzerland

The LHC is the world’s largest and most powerful particle accelerator. It is a 27-kilometre long ring of superconducting magnets buried 100 metres deep below the Alps, where physicists fire streams of particles through the tube at close to the speed of light, before crashing them headlong into one another and examining the results of these impacts.

A long-term experiment examining a type of subatomic particle called a beauty quark has revealed that when it is observed in the LHCb experiment, it breaks down into other subatomic particles at an uneven rate.

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Link to the arXiv article 

New subatomic particles could explain a surprisingly large number of decays of particles called kaons seen in the KOTO experiment (detector shown). JAPAN PROTON ACCELERATOR RESEARCH COMPLEX (J-PARC) CENTER

By Emily Conover

Certain extremely rare decays seem to be happening more often than expected

 A little-known type of particle called a kaon may be stepping into the spotlight.

The exotic subatomic particles are attracting attention for their unexpected behavior in an experiment at a Japanese particle accelerator. Rare kaon decays seem to be happening more frequently than expected, according to the KOTO experiment. If the result holds up to further scrutiny, it could hint at never-before-seen particles that would dethrone particle physicists’ reigning theory, the standard model.

There’s still a good chance KOTO’s result will be overturned, says Yuval Grossman of Cornell University. But “there’s the extremely exciting possibility that they see something totally new.”

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Peter van Nieuwenhuizen, Sergio Ferrara and Dan Freedman (left to right, in a picture from 2016) received a Breakthrough Prize for creating supergravity theory.Credit: CERN

Three physicists honoured for theory that has been hugely influential — but might not be a good description of reality.

Whether the theory of supergravity, an attempt to unify all the forces of nature, is a true description of the world still hangs in the balance more than 40 years after it was proposed. Nonetheless it has now nabbed its founders one of the most lucrative awards in science: a shared US$3-million Special Breakthrough Prize in fundamental physics.

Supergravity1 was devised in 1976 by particle physicists Sergio Ferrara of CERN, Europe’s particle-physics laboratory near Geneva, Switzerland; Daniel Freedman of the Massachusetts Institute of Technology in Cambridge; and Peter van Nieuwenhuizen of Stony Brook University in New York. The selection committee that awarded the prize chose to honour the theory, in part, for its impact on the understanding of ordinary gravity. Supergravity also underpins one of physicists’ favourite candidate ‘theories of everything’, string theory. The latter asserts that elementary particles are made of tiny threads of energy, but it remains unproven.

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LHCb. Maximilien Brice et al./CERN

March 21, 2019

Author: Marco Gersabeck
Lecturer in Physics, University of Manchester

Why do we exist? This is arguably the most profound question there is and one that may seem completely outside the scope of particle physics. But our new experiment at CERN’s Large Hadron Collider has taken us a step closer to figuring it out.

To understand why, let’s go back in time some 13.8 billion years to the Big Bang. This event produced equal amounts of the matter you are made of and something called antimatter. It is believed that every particle has an antimatter companion that is virtually identical to itself, but with the opposite charge. When a particle and its antiparticle meet, they annihilate each other – disappearing in a burst of light.

Why the universe we see today is made entirely out of matter is one of the greatest mysteries of modern physics. Had there ever been an equal amount of antimatter, everything in the universe would have been annihilated. Our research has unveiled a new source of this asymmetry between matter and antimatter.

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MASSIVE MACHINES A researcher stands in the cavernous spectrometer of KATRIN, an experiment in Germany to measure the mass of particles called neutrinos.

Physicists build giant machines to study tiny particles
BY EMILY CONOVER 9:30AM, SEPTEMBER 19, 2018

Diana Parno’s head swam when she first stepped inside the enormous, metallic vessel of the experiment KATRIN. Within the house-sized, oblong structure, everything was symmetrical, clean and blindingly shiny, says Parno, a physicist at Carnegie Mellon University in Pittsburgh. “It was incredibly disorienting.”

Now, electrons — thankfully immune to bouts of dizziness — traverse the inside of this zeppelin-shaped monstrosity located in Karlsruhe, Germany. Building the experiment took years and tens of millions of dollars. Why create such an extreme apparatus? It’s all part of a bid to measure the mass of itty-bitty subatomic particles known as neutrinos.

KATRIN, which is short for Karlsruhe Tritium Neutrino Experiment, started test runs in May. The experiment is part of a multipronged approach to the study of particle physics, one of dozens of detectors built in an assortment of odd-looking shapes and sizes. Their mission: dive deep into the standard model, particle physicists’ theory of the subatomic building blocks of matter — and maybe overthrow it.

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In this artistic rendering, a blazar emits both neutrinos and gamma rays that could be detected by the IceCube Neutrino Observatory as well as by other telescopes on Earth and in space. Credit: IceCube/NASA

By the IceCube Collaboration, 12 Jul 2018 10:00 AM

An international team of scientists has found the first evidence of a source of high-energy cosmic neutrinos, ghostly subatomic particles that can travel unhindered for billions of light years from the most extreme environments in the universe to Earth.
The observations, made by the IceCube Neutrino Observatory at the Amundsen–Scott South Pole Station and confirmed by telescopes around the globe and in Earth’s orbit, help resolve a more than a century-old riddle about what sends subatomic particles such as neutrinos and cosmic rays speeding through the universe.

Since they were first detected over one hundred years ago, cosmic rays—highly energetic particles that continuously rain down on Earth from space—have posed an enduring mystery: What creates and launches these particles across such vast distances? Where do they come from?
Because cosmic rays are charged particles, their paths cannot be traced directly back to their sources due to the powerful magnetic fields that fill space and warp their trajectories. But the powerful cosmic accelerators that produce them will also produce neutrinos. Neutrinos are uncharged particles, unaffected by even the most powerful magnetic field. Because they rarely interact with matter and have almost no mass—hence their sobriquet “ghost particle”—neutrinos travel nearly undisturbed from their accelerators, giving scientists an almost direct pointer to their source.

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Inside the MiniBooNE tank, photodetectors capture the light created when a neutrino interacts with an atomic nucleus. (Reidar Hahn / Fermilab)

Natalie Wolchover  1.6.2018

Physicists are both thrilled and baffled by a new report from a neutrino experiment at Fermi National Accelerator Laboratory near Chicago. The MiniBooNE experiment has detected far more neutrinos of a particular type than expected, a finding that is most easily explained by the existence of a new elementary particle: a “sterile” neutrino that’s even stranger and more reclusive than the three known neutrino types. The result appears to confirm the anomalous results of a decades-old experiment that MiniBooNE was built specifically to double-check.

The persistence of the neutrino anomaly is extremely exciting, said the physicist Scott Dodelson of Carnegie Mellon University. It “would indicate that something is indeed going on,” added Anže Slosar of Brookhaven National Laboratory.

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A simulation of a neutron star merger. NASA GODDARD SPACE FLIGHT CENTER

BY KATHERINE HIGNETT ON 1/19/18 AT 8:47 AM

Update | Last August, astronomers detected the massive collision of two neutron stars. This neutron star merger sent gravitational waves surging through space. It also unleashed a gamma ray burst—the world’s most powerful laser.

Normally gamma ray bursts glow brightly for a short time, then fizzle out and lose energy. New electromagnetic observations from NASA’s Chandra X-ray observatory show the burst brightening, baffling astronomers.

An exploding cocoon
A more complex explanation is needed for the bizarre brightening, the authors wrote. They propose that a "cocoon"-shaped explosion might do the job. In this model, a jet from the collision shock-heats the surrounding gas and debris, creating a boiling cocoon of matter.

The new X-ray observations support recent discoveries from radio emissions. Last month, another team of researchers reported the strengthening of radio emissions from the neutron star merger. They produced a digital reconstruction, seen in the video below, of a similar "cocoon" model.

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Natalie Wolchover -- December 18, 2017

The mother of all string theories passes a litmus test that, so far, no other candidate theory of quantum gravity has been able to match.

It’s not easy being a “theory of everything.” A TOE has the very tough job of fitting gravity into the quantum laws of nature in such a way that, on large scales, gravity looks like curves in the fabric of space-time, as Albert Einstein described in his general theory of relativity. Somehow, space-time curvature emerges as the collective effect of quantized units of gravitational energy — particles known as gravitons. But naive attempts to calculate how gravitons interact result in nonsensical infinities, indicating the need for a deeper understanding of gravity.

String theory (or, more technically, M-theory) is often described as the leading candidate for the theory of everything in our universe. But there’s no empirical evidence for it, or for any alternative ideas about how gravity might unify with the rest of the fundamental forces. Why, then, is string/M-theory given the edge over the others?

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Artist’s impression of a gamma-ray burst, a powerful flash of gamma-rays that may be emitted from the merger of a neutron star with another compact object. [ESO/A. Roquette]

By Susanna Kohler on 9 October 2017

With the first detection of gravitational waves in 2015, scientists celebrated the opening of a new window to the universe. But multi-messenger astronomy — astronomy based on detections of not just photons, but other signals as well — was not a new idea at the time: we had already detected tiny, lightweight neutrinos emitted from astrophysical sources. Will we be able to combine observations of neutrinos and gravitational waves in the future to provide a deeper picture of astrophysical events?

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Extra dimensions hiding here

Signatures of extra dimensions that don’t normally affect the four dimensions we can observe could show up in the way they warp ripples in space-time

By Leah Crane

HIDDEN dimensions could cause ripples through reality by modifying gravitational waves – and spotting such signatures of extra dimensions could help solve some of the biggest mysteries of the universe.

Physicists have long wondered why gravity is so weak compared with the other fundamental forces. This may be because some of it is leaking away into extra dimensions beyond the three spatial dimensions we experience.

Some theories that seek to explain how gravity and quantum effects mesh together, including string theory, require extra dimensions, often with gravity propagating through them. Finding evidence of such exotic dimensions could therefore help to characterise gravity, or find a way to unite gravity and quantum mechanics – it could also hint at an explanation for why the universe’s expansion is accelerating.

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Colour composite photo of the sky field around the lonely neutron star RX J1856.5-3754 in the constellation of Corona Australis and the related cone-shaped nebula. It is based on a series of exposures obtained with the multi-mode FORS2 instrument at VLT KUEYEN through three different optical filters. The trail of an asteroid is seen in the field with intermittent blue, green and red colours. RX J1856.5-3754 is exactly in the centre of the image. Image credit: ESO.

By studying the light emitted from an extraordinarily dense and strongly magnetised neutron star using ESO’s Very Large Telescope, astronomers may have found the first observational indications of a strange quantum effect, first predicted in the 1930s. The polarisation of the observed light suggests that the empty space around the neutron star is subject to a quantum effect known as vacuum birefringence.
A team led by Roberto Mignani from INAF Milan (Italy) and from the University of Zielona Gora (Poland), used ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile to observe the neutron star RX J1856.5-3754, about 400 light-years from Earth.

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These particle tracks from the CMS experiment at the LHC show two photons arising from a roughly 750-GeV particle created in a proton-proton collision. The event may represent a new particle beyond the Standard Model of physics.
Credit: CERN

The gigantic accelerator in Europe has produced hints of an exotic particle that defies the known laws of physics
By Clara Moskowitz on December 16, 2015

A little wiggle on a graph, representing just a handful of particles, has set the world of physics abuzz. Scientists at the Large Hadron Collider (LHC) in Switzerland, the largest particle accelerator on Earth, reported yesterday that their machine might have produced a brand new particle not included in the established laws of particle physics known as the Standard Model. Their results, based on the data collected from April to November after the LHC began colliding protons at nearly twice the energy of its previous runs, are too inconclusive to be sure—many physicists warned that the wiggle could just as easily represent a statistical fluke. Nevertheless, the finding has already spawned at least 10 new papers in less than a day proposing a theoretical explanation for the particle, and has the halls and blackboards of physics departments around the world churning.

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