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Category: particle physics – Page 443

Highest-Energy Cosmic Rays Detected in Star Clusters – Energies Beyond Those From Supernovae Capable of Devouring Entire Solar Systems

For decades, researchers assumed the cosmic rays that regularly bombard Earth from the far reaches of the galaxy are born when stars go supernova — when they grow too massive to support the fusion occurring at their cores and explode.

Those gigantic explosions do indeed propel atomic particles at the speed of light great distances. However, new research suggests even supernovae — capable of devouring entire solar systems — are not strong enough to imbue particles with the sustained energies needed to reach petaelectronvolts (PeVs), the amount of kinetic energy attained by very high-energy cosmic rays.

And yet cosmic rays have been observed striking Earth’s atmosphere at exactly those velocities, their passage marked, for example, by the detection tanks at the High-Altitude Water Cherenkov (HAWC) observatory near Puebla, Mexico. Instead of supernovae, the researchers posit that star clusters like the Cygnus Cocoon serve as PeVatrons — PeV accelerators — capable of moving particles across the galaxy at such high energy rates.

IceCube Detection of a High-Energy Particle – Antineutrino “Unmistakably of Extraterrestrial Origin”

The South Pole neutrino detector saw a Glashow resonance event, a phenomenon predicted by Nobel laureate physicist Sheldon Glashow in 1960 where an electron antineutrino and an electron interact to produce a W-boson.

On December 62016, a high-energy particle called an electron antineutrino hurtled to Earth from outer space at close to the speed of light carrying 6.3 petaelectronvolts (PeV) of energy. Deep inside the ice sheet at the South Pole, it smashed into an electron and produced a particle that quickly decayed into a shower of secondary particles. The interaction was captured by a massive telescope buried in the Antarctic glacier, the IceCube Neutrino Observatory.

Physicists Measure the Gravitational Force between the Smallest Masses Yet

But Aspelmeyer and his colleagues could not declare victory quite yet: they still had to rule out the possibility that the source mass modulation was generating other forces on the test mass that would oscillate at precisely the same frequency. Periodic rocking of the table supporting the experimental apparatus, caused by recoil from the barely visible motion of the source mass, was just one of a host of confounders the researchers had to carefully quantify. In the end, they found that all known nongravitational forces would be at least 10 times smaller than the gravitational interaction.

Reaching toward Quantum Scales

Aspelmeyer believes that an improved torsion pendulum will be sensitive to gravity from masses 5000 times smaller still—lighter than a single eyelash. His ultimate goal is to experimentally test the quantum nature of gravity, a question that has perplexed physicists for nearly a century. Quantum mechanics is one of the most successful and precisely tested theories in all of science: it describes everything from the behavior of subatomic particles to the semiconductor physics that makes modern computing possible. But attempts to develop a quantum theory of gravity have repeatedly been stymied by contradictory and nonsensical predictions.

Swirlonic state of active matter

Hence, while the fast particles are abundant in molecular systems, they are practically lacking in active matter. These fast particle can overcome the attraction forces of the molecular surrounding and give rise to the gaseous phase; the lack of fast particles in active matter results in the lack of the gas, coexisting with the liquid phase. If the particle density is still larger and the repulsive forces are strong, the active matter falls into a solid phase, Fig. 1 d, where the particles mobility is suppressed.

In some range of parameters a novel swirlonic phase is formed, Fig. 1e. It is comprised of swirlons —“super-particles” with many astonishing properties which we address below. Individual active particles in swirlons perform a swirling motion around their common center. As we demonstrate in what follows, the swirlons are formed when local fluctuating force exceeds the critical force, which characterizes the ability of an active particle to move against an applied load.

Finally, for large density and very strong attractive forces a collapsed state is observed, Fig. 1 f. In the collapsed state active particle also move around the common center, however the character of the motion is rather irregular. In the present study we will focus on the gaseous, liquid and especially on the swirlonic phase.

Physicists Just Found 4 New Subatomic Particles That May Test The Laws of Nature

This month is a time to celebrate. CERN has just announced the discovery of four brand new particles at the Large Hadron Collider (LHC) in Geneva.

This means that the LHC has now found a total of 59 new particles, in addition to the Nobel prize-winning Higgs boson, since it started colliding protons – particles that make up the atomic nucleus along with neutrons – in 2009.

Excitingly, while some of these new particles were expected based on our established theories, some were altogether more surprising.

In the Race to Hundreds of Qubits, Photons May Have “Quantum Advantage”

Canadian startup Xanadu says their quantum computer is cloud-accessible, Python programmable, and ready to scale.

Quantum computers based on photons may have some advantages over electron-based machines, including operating at room temperature and not temperatures colder than that of deep space. Now, say scientists at quantum computing startup Xanadu, add one more advantage to the photon side of the ledger. Their photonic quantum computer, they say, could scale up to rival or even beat the fastest classical supercomputers—at least at some tasks.

Whereas conventional computers switch transistors either on or off to symbolize data as ones and zeroes, quantum computers use quantum bits or “qubits” that, because of the bizarre nature of quantum physics, can exist in a state known as superposition where they can act as both 1 and 0. This essentially lets each qubit perform multiple calculations at once.

The more qubits are quantum-mechanically connected entangled together, the more calculations they can simultaneously perform. A quantum computer with enough qubits could in theory achieve a “quantum advantage” enabling it to grapple with problems no classical computer could ever solve. For instance, a quantum computer with 300 mutually-entangled qubits could theoretically perform more calculations in an instant than there are atoms in the visible universe.

Eerie Stars of ‘Dark Matter’ May Be Behind Largest Gravitational Wave Detection Yet

On 21 May 2019, from a distance of 7 billion light-years away, our gravitational wave detectors were rocked by the most massive collision yet. From analysis of the signal, astronomers concluded that the detection was the result of two black holes smashing together, weighing in at 66 and 85 times the mass of the Sun respectively.

But what if it was something else? A new study offers a different interpretation of the event. It’s possible, according to an international team of astrophysicists, that the two objects were not black holes at all, but mysterious, theoretical objects called boson stars — potentially made up of elusive candidates for dark matter.

The gravitational wave event, called GW 190521, was a spectacular discovery. The object that resulted from the merger of the two objects would have been a black hole at around 142 times the mass of the Sun — within the intermediate mass range that no black hole had ever been detected before, called the black hole upper mass gap.

A Decades-Long Quest Reveals New Details of Antimatter

Planned future experiments will help researchers choose between the two pictures. But whichever model is right, SeaQuest’s hard data about the proton’s inner antimatter will be immediately useful, especially for physicists who smash protons together at nearly light speed in Europe’s Large Hadron Collider. When they know exactly what’s in the colliding objects, they can better piece through the collision debris looking for evidence of new particles or effects. Juan Rojo of VU University Amsterdam, who helps analyze LHC data, said the SeaQuest measurement “could have a big impact” on the search for new physics, which is currently “limited by our knowledge of the proton structure, in particular of its antimatter content.”

Twenty years ago, physicists began investigating a mysterious asymmetry inside the proton. Their results show how antimatter helps stabilize every atom’s core.