sábado, 30 de agosto de 2014

Physicists Directly Detect Neutrinos From Sun's Core | IFLScience

Physicists Directly Detect Neutrinos From Sun's Core | IFLScience

Neutrinos are elementary particles that are difficult to detect because they very rarely interact with ordinary matter. There are three varieties, or “flavors,” of neutrinos: electron, muon, and tau. Neutrinos forged in the Sun’s core are electron neutrinos, but can change between the other two over time. An international team of over 100 physicists, led in part by Andrea Pocar from the University of Massachusetts Amherst, have been able to directly detect neutrinos from the core of the Sun and describe the particles’ behavior.

The Sun is fueled by nuclear fusion, the majority of which convert hydrogen atoms into helium. During this reaction, neutrinos are produced and ejected out of the Sun. Though Earth is constantly getting bombarded with countless neutrinos, the majority pass through the planet without actually interacting with anything, which is why they are hard to detect.

Pocar explained the crux of the experiment in a press release:

By comparing the two different types of solar energy radiated, as neutrinos and as surface light, we obtain experimental information about the Sun's thermodynamic equilibrium over about a 100,000-year timescale. If the eyes are the mirror of the soul, with these neutrinos, we are looking not just at its face, but directly into its core. We have glimpsed the sun's soul.

As far as we know, neutrinos are the only way we have of looking into the Sun's interior. These pp neutrinos, emitted when two protons fuse forming a deuteron, are particularly hard to study. This is because they are low energy, in the range where natural radioactivity is very abundant and masks the signal from their interaction."

The neutrinos were detected by interacting with electrons in a Carbon-14-depleted medium that had been placed in the center of a giant sphere that holds nearly 240,000 gallons of incredibly pure water.

"We pushed the detector sensitivity to a limit that has never been achieved before."

lunes, 25 de agosto de 2014

A variety of magnetic materials can be controlled using only polarized light, according to new work carried out by an international team of researchers.

Lighting up: controlling magnetic materials with light.

A variety of magnetic materials can be controlled using only polarized light, according to new work carried out by an international team of researchers.

The unexpected and so far unexplained discovery shows that the optical phenomenon, which was previously thought to be possible only in ferrimagnets, is actually much more general.

The discovery could potentially have a major impact on data storage, as it could allow magnetic bits to be rapidly switched by optical pulses in state-of-the-art hard drives.

From magnetic tapes to computer hard drives, rewritable data storage has traditionally been achieved using ordering of magnetic domains.


lunes, 18 de agosto de 2014

Simulation Shows Time Travel Is Possible

Simulation Shows Time Travel Is Possible

on 13 August, 2014 at 15:19

Australian scientists created  a computer simulation in which quantum particles can move back in time.

At the same time, the study revealed a number of effects which are considered impossible according to the standard quantum mechanics.

Using photons, physicists from the University of Queensland in Australia simulated time-traveling quantum particles. a path followed by a particle which returns to its initial space-time point.

According to the researchers, their study will help to find a link between two great theories in physics: the Einstein’s general theory of relativity and quantum mechanics.


miércoles, 7 de mayo de 2014

The Large Hadron Collider may have found a new form of matter

Scientists have discovered an elusive particle that may be an example of a tetraquark, an entirely new form of matter.

Experiments at the Large Hadron Collider, the overachieving device famous for finding the Higgs boson, have confirmed that a new particle called Z(4430) exists, and is the best evidence to date of a new form of matter called a tetraquark.

And now the LHC has spotted as many as 4,000 of the elusive particles, the researchers reported in ArXiv.org .

Before you get too excited, there is still work to be done to determine if Z(4430) really is a tetraquark, and, if so, what that means for us.

Thomas Cohen at the University of Maryland in College Park told New Scientist : "Our computers aren't yet big enough to solve the theory from first principles."

But the big first hurdle has been overcome - scientists have proved that Z(4430) really does exist and shown there's still so much we have to discovery about the world we live in.


martes, 11 de marzo de 2014

750km of solid rock: new long-baseline neutrino results

Neutrino physics is one of the fastest-developing areas of particle physics.

Two ‘long-baseline’ neutrino experiments, in the US and Japan, reported results last week

Neutrinos are peculiar particles.

They are very common, billions are passing through you all the time.

Perhaps it is fortunate then that they very rarely interact with matter, and therefore do you no harm as they pass through.

They rarely interact because, uniquely among all the fundamental particles we know of that make up the matter in the universe, they only experience two of the four fundamental forces.

The have mass and energy, so they feel the gravitational force, and they also feel the weak force (that is the one carried by W and Z bosons).

But they have no charge, so they are invisible to the electromagnetic force; and the strong nuclear force also ignores them.

One thing we know about neutrinos is that when they are produced, they are one of three definite types – an electron, muon or tau type.

These types are known as flavours.

Flavour is just a label for the type of particle they can produce when they interact.

But a weird thing, which we also know, is that though there are neutrinos of three different flavours, and neutrinos of three different masses, the correspondence between the masses and the flavours is not straightforward.

The mixing between them is described by a matrix , with four different parameters that characterise how the mixing happens – basically what proportions of one kind of neutrino make up another.

(These cosmic rays produce many different kinds of particle, including neutrinos.)

Once you have built a neutrino detector (they are very big and very sensitive) you will most likely try to use any neutrinos you can, wherever they come from.


jueves, 27 de febrero de 2014

Quantum droplet In the field of quantum physics, you could call this a droplet in the bucket.

Writing in the journal Nature , they say it behaves a bit like a liquid droplet and described it as a quasiparticle — an amalgamation of smaller types of particles.

The discovery, they add, could be useful in the development of nanotechnology, including the design of optoelectronic devices.

These include things like semiconductor lasers used in Blu-ray disc players.

That does not sound like much, but the scientists say it is stable enough for research on how light interacts with certain types of matter.


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