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Nosso universo vai congelar como uma cerveja super-resfriada…

SCIENTIFIC METHOD / SCIENCE & EXPLORATION

Finding the Higgs? Good news. Finding its mass? Not so good.

“Fireballs of doom” from a quantum phase change would wipe out present Universe.

by  – Feb 19 2013, 8:55pm HB

A collision in the LHC’s CMS detector.

Ohio State’s Christopher Hill joked he was showing scenes of an impending i-Product launch, and it was easy to believe him: young people were setting up mats in a hallway, ready to spend the night to secure a space in line for the big reveal. Except the date was July 3 and the location was CERN—where the discovery of the Higgs boson would be announced the next day.

It’s clear the LHC worked as intended and has definitively identified a Higgs-like particle. Hill put the chance of the ATLAS detector having registered a statistical fluke at less than 10-11, and he noted that wasn’t even considering the data generated by its partner, the CMS detector. But is it really the one-and-only Higgs and, if so, what does that mean? Hill was part of a panel that discussed those questions at the meeting of the American Association for the Advancement of Science.

As theorist Joe Lykken of Fermilab pointed out, the answers matter. If current results hold up, they indicate the Universe is currently inhabiting what’s called a false quantum vacuum. If it were ever to reach the real one, its existing structures (including us), would go away in what Lykken called “fireballs of doom.”

We’ll look at the less depressing stuff first, shall we?

Zeroing in on the Higgs

Thanks to the Standard Model, we were able to make some very specific predictions about the Higgs. These include the frequency with which it will decay via different pathways: two gamma-rays, two Z bosons (which further decay to four muons), etc. We can also predict the frequency of similar looking events that would occur if there were no Higgs. We can then scan each of the decay pathways (called channels), looking for energies where there is an excess of events, or bump. Bumps have shown up in several channels in roughly the same place in both CMS and ATLAS, which is why we know there’s a new particle.

But we still don’t know precisely what particle it is. The Standard Model Higgs should have a couple of properties: it should be scalar and should have a spin of zero. According to Hill, the new particle is almost certainly scalar; he showed a graph where the alternative, pseudoscalar, was nearly ruled out. Right now, spin is less clearly defined. It’s likely to be zero, but we haven’t yet ruled out a spin of two. So far, so Higgs-like.

The Higgs is the particle form of a quantum field that pervades our Universe (it’s a single quantum of the field), providing other particles with mass. In order to do that, its interactions with other particles vary—particles are heavier if they have stronger interactions with the Higgs. So, teams at CERN are sifting through the LHC data, checking for the strengths of these interactions. So far, with a few exceptions, the new particle is acting like the Higgs, although the error bars on these measurements are rather large.

As we said above, the Higgs is detected in a number of channels and each of them produces an independent estimate of its mass (along with an estimated error). As of the data Hill showed, not all of these estimates had converged on the same value, although they were all consistent within the given errors. These can also be combined mathematically for a single estimate, with each of the two detectors producing a value. So far, these overall estimates are quite close: CMS has the particle at 125.8GeV, Atlas at 125.2GeV. Again, the error bars on these values overlap.

Oops, there goes the Universe

That specific mass may seem fairly trivial—if it were 130GeV, would you care? Lykken made the argument you probably should. But he took some time to build to that.

Lykken pointed out, as the measurements mentioned above get more precise, we may find the Higgs isn’t decaying at precisely the rates we expect it to. This may be because we have some details of the Standard Model wrong. Or, it could be a sign the Higgs is also decaying into some particles we don’t know about—particles that are dark matter candidates would be a prime choice. The behavior of the Higgs might also provide some indication of why there’s such a large excess of matter in the Universe.

But much of Lykken’s talk focused on the mass. As we mentioned above, the Higgs field pervades the entire Universe; the vacuum of space is filled with it. And, with a value for the Higgs mass, we can start looking into the properties of the Higgs filed and thus the vacuum itself. “When we do this calculation,” Lykken said, “we get a nasty surprise.”

It turns out we’re not living in a stable vacuum. Eventually, the Universe will reach a point where the contents of the vacuum are the lowest energy possible, which means it will reach the most stable state possible. The mass of the Higgs tells us we’re not there yet, but are stuck in a metastable state at a somewhat higher energy. That means the Universe will be looking for an excuse to undergo a phase transition and enter the lower state.

What would that transition look like? In Lykken’s words, again, “fireballs of doom will form spontaneously and destroy the Universe.” Since the change would alter the very fabric of the Universe, anything embedded in that fabric—galaxies, planets, us—would be trashed during the transition. When an audience member asked “Are the fireballs of doom like ice-9?” Lykken replied, “They’re even worse than that.”

Lykken offered a couple of reasons for hope. He noted the outcome of these calculations is extremely sensitive to the values involved. Simply shifting the top quark’s mass by two percent to a value that’s still within the error bars of most measurements, would make for a far more stable Universe.

And then there’s supersymmetry. The news for supersymmetry out of the LHC has generally been negative, as various models with low-mass particles have been ruled out by the existing data (we’ll have more on that shortly). But supersymmetry actually predicts five Higgs particles. (Lykken noted this by showing a slide with five different photos of Higgs taken at various points in his career, in which he was “differing in mass and other properties, as happens to all of us.”) So, when the LHC starts up at higher energies in a couple of years, we’ll actually be looking for additional, heavier versions of the Higgs.

If those are found, then the destruction of our Universe would be permanently put on hold. “If you don’t like that fate of the Universe,” Lykken said, “root for supersymmetry”

Determinando se vivemos dentro da Matrix

The Measurement That Would Reveal The Universe As A Computer Simulation

If the cosmos is a numerical simulation, there ought to be clues in the spectrum of high energy cosmic rays, say theorists

1 comment

THE PHYSICS ARXIV BLOG

Wednesday, October 10, 2012

One of modern physics’ most cherished ideas is quantum chromodynamics, the theory that describes the strong nuclear force, how it binds quarks and gluons into protons and neutrons, how these form nuclei that themselves interact. This is the universe at its most fundamental.

So an interesting pursuit is to simulate quantum chromodynamics on a computer to see what kind of complexity arises. The promise is that simulating physics on such a fundamental level is more or less equivalent to simulating the universe itself.

There are one or two challenges of course. The physics is mind-bogglingly complex and operates on a vanishingly small scale. So even using the world’s most powerful supercomputers, physicists have only managed to simulate tiny corners of the cosmos just a few femtometers across. (A femtometer is 10^-15 metres.)

That may not sound like much but the significant point is that the simulation is essentially indistinguishable from the real thing (at least as far as we understand it).

It’s not hard to imagine that Moore’s Law-type progress will allow physicists to simulate significantly larger regions of space. A region just a few micrometres across could encapsulate the entire workings of a human cell.

Again, the behaviour of this human cell would be indistinguishable from the real thing.

It’s this kind of thinking that forces physicists to consider the possibility that our entire cosmos could be running on a vastly powerful computer. If so, is there any way we could ever know?

Today, we get an answer of sorts from Silas Beane, at the University of Bonn in Germany, and a few pals.  They say there is a way to see evidence that we are being simulated, at least in certain scenarios.

First, some background. The problem with all simulations is that the laws of physics, which appear continuous, have to be superimposed onto a discrete three dimensional lattice which advances in steps of time.

The question that Beane and co ask is whether the lattice spacing imposes any kind of limitation on the physical processes we see in the universe. They examine, in particular, high energy processes, which probe smaller regions of space as they get more energetic

What they find is interesting. They say that the lattice spacing imposes a fundamental limit on the energy that particles can have. That’s because nothing can exist that is smaller than the lattice itself.

So if our cosmos is merely a simulation, there ought to be a cut off in the spectrum of high energy particles.

It turns out there is exactly this kind of cut off in the energy of cosmic ray particles,  a limit known as the Greisen–Zatsepin–Kuzmin or GZK cut off.

This cut-off has been well studied and comes about because high energy particles interact with the cosmic microwave background and so lose energy as they travel  long distances.

But Beane and co calculate that the lattice spacing imposes some additional features on the spectrum. “The most striking feature…is that the angular distribution of the highest energy components would exhibit cubic symmetry in the rest frame of the lattice, deviating significantly from isotropy,” they say.

In other words, the cosmic rays would travel preferentially along the axes of the lattice, so we wouldn’t see them equally in all directions.

That’s a measurement we could do now with current technology. Finding the effect would be equivalent to being able to to ‘see’ the orientation of lattice on which our universe is simulated.

That’s cool, mind-blowing even. But the calculations by Beane and co are not without some important caveats. One problem is that the computer lattice may be constructed in an entirely different way to the one envisaged by these guys.

Another is that this effect is only measurable if the lattice cut off is the same as the GZK cut off. This occurs when the lattice spacing is about 10^-12 femtometers. If the spacing is significantly smaller than that, we’ll see nothing.

Nevertheless, it’s surely worth looking for, if only to rule out the possibility that we’re part of a simulation of this particular kind but secretly in the hope that we’ll find good evidence of our robotic overlords once and for all.

Ref: arxiv.org/abs/1210.1847: Constraints on the Universe as a Numerical Simulation

Origens da Massa

A ler com cuidad, Wilczek sempre é muito didático…

Origins of Mass

Frank Wilczek
(Submitted on 29 Jun 2012 (v1), last revised 22 Aug 2012 (this version, v2))

Newtonian mechanics posited mass as a primary quality of matter, incapable of further elucidation. We now see Newtonian mass as an emergent property. Most of the mass of standard matter, by far, arises dynamically, from back-reaction of the color gluon fields of quantum chromodynamics (QCD). The equations for massless particles support extra symmetries – specifically scale, chiral, and gauge symmetries. The consistency of the standard model relies on a high degree of underlying gauge and chiral symmetry, so the observed non-zero masses of many elementary particles ($W$ and $Z$ bosons, quarks, and leptons) requires spontaneous symmetry breaking. Superconductivity is a prototype for spontaneous symmetry breaking and for mass-generation, since photons acquire mass inside superconductors. A conceptually similar but more intricate form of all-pervasive (i.e. cosmic) superconductivity, in the context of the electroweak standard model, gives us a successful, economical account of $W$ and $Z$ boson masses. It also allows a phenomenologically successful, though profligate, accommodation of quark and lepton masses. The new cosmic superconductivity, when implemented in a straightforward, minimal way, suggests the existence of a remarkable new particle, the so-called Higgs particle. The mass of the Higgs particle itself is not explained in the theory, but appears as a free parameter. Earlier results suggested, and recent observations at the Large Hadron Collider (LHC) may indicate, the actual existence of the Higgs particle, with mass $m_H \approx 125$ GeV. In addition to consolidating our understanding of the origin of mass, a Higgs particle with $m_H \approx 125$ GeV could provide an important clue to the future, as it is consistent with expectations from supersymmetry.

Comments: Invited review for the Central European Journal of Physics. This is the supplement to my 2011 Solvay Conference talk promised there. It is adapted from an invited talk given at the Atlanta APS meeting, April 2012. 33 pages, 6 figures. v2: Added update section bringing in the CERN discovery announcement
Subjects: High Energy Physics – Phenomenology (hep-ph); History and Philosophy of Physics (physics.hist-ph)
Report number: MIT-CTP 4379
Cite as: arXiv:1206.7114v2 [hep-ph]

Físicos apostadores

Acho que estou devendo uma pizza para o Jorge Stolfi. Como disse Giovani Amelino-Camelia, a chance dos neutrinos superluminais realmente existirem era de uma para dez mil, mas apostar nessa possibilidade era por demais tentador, pois participar de uma revolução científica com essa chance é bem melhor do que apenas fazer trabalhos tecnicamente corretos e mesmo elegantes,  mas de significância marginal. 

Phenomenology of Philosophy of Science: OPERA data

Giovanni Amelino-Camelia
(Submitted on 15 Jun 2012)

I observe that, as the physics side of the OPERA-anomaly story is apparently unfolding, there can still be motivation for philosophy of science to analyze the six months of madness physicists spent chasing the dream of a new fundamental-physics revolution. I here mainly report data on studies of the OPERA anomaly that could be relevant for analyses from the perspective of phenomenology of philosophy of science. Most of what I report is an insider’s perspective on the debate that evolved from the original announcement by the OPERA collaboration of evidence of superluminal neutrinos. I also sketch out, from a broader perspective, some of the objectives I view as achievable for the phenomenology of philosophy of science.

Comments: 13 pages, LaTex
Subjects: History and Philosophy of Physics (physics.hist-ph); High Energy Physics – Experiment (hep-ex); High Energy Physics – Phenomenology (hep-ph)
Cite as: arXiv:1206.3554v1 [physics.hist-ph]

After Particle Search, Some Wallets May Lose Mass

By 

When physicists at CERN reported on July 4 that they had discovered a new particle resembling the long-sought Higgs boson, it prompted a worldwide celebration of pride and mystification.

It also prompted a worldwide settling of scores as physicists — inveterate gamblers — examine the data to decide whether it is time to pay up on longstanding bets about the existence of the boson, which has been the object of a 40-year manhunt.

As described by the Standard Model, the theory that now rules physics, the Higgs boson would be tangible evidence of a hypothesized cosmic molasses known as the Higgs field. That field endows some elementary particles with mass, breaking a logjam of mathematical symmetry in the laws of the early universe and thus adding diversity and the possibility of life to the cosmos. Physicists say it will take them at least the rest of the year and maybe longer to ascertain whether the new particle fits the theoretical prediction — in particular that it has no spin, the first known subatomic knuckle ball.

Nevertheless, the British cosmologist Stephen Hawking, who 10 years ago bet the University of Michigan theorist Gordon Kane $100 that the particle didn’t exist, has already told reporters he is conceding defeat. Dr. Kane is awaiting his windfall. “I haven’t heard directly from him,” Dr. Kane said in an e-mail, “but I assume I will soon, in some interesting way.” Read more [+]

Emaranhados no tempo

New Type Of Entanglement Allows ‘Teleportation in Time,’ Say Physicists

Conventional entanglement links particles across space. Now physicists say a similar effect links particles through time.

KFC 01/17/2011

  • 29 COMMENTS

Entanglement is the strange quantum phenomenon in which two or more particles become so deeply linked that they share the same existence.

That leads to some counterintuitive effects, in particular, when two entangled particles become widely separated. When that happens, a measurement on one immediately influences the other, regardless of the distance between them. This “spooky-action-at-a-distance” has profound implications about the nature of reality but a clear understanding of it still eludes physicists.

Today, they have something else to puzzle over. Jay Olson and Timothy Ralph at the University of Queensland in Australia say they’ve discovered a new type of entanglement that extends, not through space, but through time. Read more [+]

Neutrinos, Higgs e LHC no BLOGPULSE

Higgs Bolon (Bolão do Higgs)


Higgs Bolon (Bolão do Higgs)

Choose your educated guess about the mass of the Higgs Boson or its existence and comment it. To participate there is a fee of US$ 100. You must not sign as an anonymous in the comments.

A. The Higgs boson has a mass in the interval 120-130 Gev as annouced by LHC.

B. The Higgs boson has a mass out of that interval.

C. The Higgs boson does not exist.

The comments close in January 31, 2012, and the prize shall be shared when LHC announces a five sigma result or a retractation of the claim about evidence for a Higgs boson mass around 125 GeV. 

Comparando os dois experimentos do OPERA sobre neutrinos superluminais

OK, OK, sei que é feio o simples cut and paste (o SEMCIÊNCIA ganhou o prêmio Tartaruga no II EWCLiPo por causa disso) mas preciso registrar aqui o ótimo post do Matt Strassler sobre os experimentos do OPERA, para futuras referências.

Of Particular Significance

Conversations About Science with Theoretical Physicist Matt Strassler

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OPERA: Comparing the Two Versions

Matt Strassler 11/19/11Ok, here’s the latest, as I currently understand it, on the OPERA experiment’s measurement that suggests (if it is correct in all respects) that neutrinos might be traveling faster than the speed of light, which in the standard version of Einstein’s theory of special relativity should be the ultimate speed limit that no particles can exceed.

Warning: For the moment not all numbers are double-checked, and there might, in places, be a number that’s off by as much as a factor of 10. But there should be no major errors. Also, I’m going to be restructuring the website a little bit and will add more cross-links between this article and the various OPERA articles and posts that I’ve put up. Apologies if there’s a bit of construction going on while you’re here. Read more [+]

Estamos em um período revolucionário na Física? Neutrinos anômalos, anti-mesons anômalos e Multiverso como ortodoxia

Achei um blog muito bom para seguir o desdobramento da controvérsia sobre os neutrinos aparentemente superluminais:

Of Particular Significance

Conversations About Science with Theoretical Physicist Matt Strassler

Cientistas famosos como Lee Smolin comentam neste blog. Acho que vou começar a seguir o caso dos neutrinos apenas por este blog e evitar as notícias de jornal e de revistas de divulgação. O blog também comenta sobre as tentativas de explicaçãoda anomalia que estão saindo no ArXiv. O status atual, segundo Matt, é que mesmo o paper do ICARUS e o paper de CG não constituem uma refutação dos resultados do OPERA, pois usam pressupostos teóricos que podem estar errados caso a relação de dispersão dos neutrinos seja outra que a da relatividade restrita. E, ao contrário de Jorge Stolfi, Matt não acredita que o problema com o OPERA tem a ver com as medidas de distância e tempo.

Neutrinos and multiverses: a new cosmology beckons

You wait decades for discoveries that could revolutionise physics, then three come along at once

“THE universe is not only queerer than we suppose, but queerer than we can suppose,” as geneticist J. B. S. Haldane once remarked. In recent decades, physicists have done their best to prove Haldane wrong, by supposing some very queer universes indeed.

Their speculations may seem fantastical, but they are well motivated. Physics poses some formidable questions that we are so far unable to answer. Why is the universe dominated by matter not antimatter? Why does our universe appear to be “fine-tuned” with just the right properties to give rise to galaxies, stars, planets, life and physicists?

The existing edifice of physics, built upon the twin foundations of general relativity and quantum mechanics, is clearly in need of renovation. We have been waiting for years for cracks to appear that might tell us how to go about it. But up to now, nature has remained stubbornly unmoved.

In the past few weeks, however, promising cracks have opened up. In September came stunning news of neutrinos travelling faster than the speed of light. Sceptics withheld judgement but now a new analysis has affirmed the initial result (see “More data shows neutrinos still faster than light”). We still await independent verification – doubts have already been cast – but if it holds up the implications are enormous, opening the door to a new and very different picture of the cosmos.

No less tantalising is a report that particles called mesons decay differently from their antimatter counterparts, anti-mesons (see “LHC antimatter anomaly hints at new physics”). If this result stands up, it would go a long way towards explaining why we have more matter than antimatter. More importantly, it would prise open the standard model of particle physics – which cannot explain the result – and point the way to yet more new physics.

The widest crack of all concerns a theory once considered outlandish but now reluctantly accepted as the orthodoxy. Almost everything in modern physics, from standard cosmology and quantum mechanics to string theory, points to the existence of multiple universes – maybe 10500 of them, maybe an infinite number (see “The ultimate guide to the multiverse”).

If our universe is just one of many, that solves the “fine-tuning” problem at a stroke: we find ourselves in a universe whose laws are compatible with life because it couldn’t be any other way. And that would just be the start of a multiverse-fuelled knowledge revolution.

Conclusive evidence may be close at hand. Theorists predict that our universe might once have collided with others. These collisions could have left dents in the cosmic microwave background, the universe’s first light, which the European Space Agency’s Planck satellite is mapping with exquisite precision. The results are eagerly awaited, and could trigger a revolution not unlike the ones unleashed by Copernicus’s idea that the Earth is not the centre of the solar system and Edwin Hubble’s discovery that our galaxy is just one among many in an expanding universe.

These are exciting, possibly epoch-making, times. Our understanding of the universe stands on the brink of being remade once again. The universe may indeed be queerer than we can suppose, but that was never going to stop us from trying.

Bolão dos neutrinos – nova rodada

Ivan entrou no bolão e apostou comigo os R$ 100. O término do bolão ficou marcado para o dia 21 de dezembro de 2012. Caso você queira participar, inscreva-se abaixo. As opções são:

A. A anomalia dos neutrinos superluminais decorrem de um erro sistemático de natureza experimental não levado em conta pelos pesquisadores da colaboração OPERA.

B. A anomalia será explicada por uma aplicação não trivial de física teórica  já conhecida (consensual).

C. A anomalia será explicada por uma proposta de física nova que não viola a simetria de Lorentz.

D. A anomalia será explicada por uma proposta de física nova que viola a simetria de Lorentz.

Façam suas apostas. Como na divisão do bolão o ganho é maior para quem apostar na hipótese mais improvável, uma análise de custo-benefício racional me diz que o melhor é apostar no item D. Está apostado!

New results show neutrinos still faster than light

Read more: “Neutrinos: Complete guide to the ghostly particle

One of the most staggering results in physics – that neutrinos may go faster than light – has not gone away with two further weeks of observations. The researchers behind the jaw-dropping finding are now confident enough in the result that they are submitting it to a peer-reviewed journal.

“The measurement seems robust,” says Luca Stanco of the National Institute of Nuclear Physics in Padua, Italy. “We have received many criticisms, and most of them have been washed out.”

Stanco is a member of the OPERA collaboration, which shocked the world in September with the announcement that the ghostly subatomic particles had arrived at the Gran Sasso mine in Italy about 60 nanoseconds faster than light speed from the CERN particle accelerator near Geneva, Switzerland, 730 kilometres away.

Tighter bunches

Theorists have been struggling to reconcile the September result with the laws of physics. Einstein’s theory of special relativity posits that nothing can travel faster than light, and many physicists believe the result could disappear in a puff of particles.

The result also unsettled those within the OPERA collaboration. Stanco was one of 15 team members who did not sign the original preprint of the paperbecause they thought the results were too preliminary.

One of the main concerns was that it was difficult to link individual neutrino hits at Gran Sasso to the particles that left CERN. To double check, the team ran a second set of measurements with tighter bunches of particles from 21 October to 6 November.

In that time, they observed 20 new neutrino hits – a piddling number compared with the 16,000 hits in the original experiment. But Stanco says the tighter particle bunches made those hits easier to track and time: “So they are very powerful, these 20 events.”

More checks

The team also rechecked their statistical analysis, confirming that the error on their measurements was indeed 10 nanoseconds. Some team members, including Stanco, had worried that the true error was larger. What they found was “absolutely compatible” with the original announcement, he says.

That was enough for Stanco to put his name to the paper, although he says six or seven team members are still holding out. The team was planning to submit the paper to a European physics journal on Thursday.

They are still running other tests, including measuring the length of a fibre-optic cable that carries information from the underground lab at Gran Sasso to a data-collection centre on the surface. The team is also trying to do the same test using another detector at the lab called RPC. That test will take another several months.

Even though he agreed to sign the paper, Stanco says: “I’m not so happy. From a theoretical point of view, it is not so appealing. I still feel that another experiment should make the measurement before I will say that I believe this result.”

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Desafio aos físicos céticos: Bolão dos Neutrinos

OK, OK, acho que ganhei o ultimo bolao dos neutrinos, dado que em poucos dias o ArXiv recebeu mais de trinta papers sobre os neutrinos superluminais.

Então lanço um novo desafio aos meus amigos físicos céticos.

Bolão de R$ 100 reais, basta assinar nos comentários para participar.

Duas opções:

A. De 01 de novembro a 21 de dezembro haverá mais papers no ArXiv com a opinião de que os resultados do OPERA refletem física nova, ou melhor, envolverão a frase: Caso os resultados do OPERA se confirmem, a minha ideia é que isso se deve a tal e tal fisica nova não convencional, envolvendo quebra de simetria de Lorentz.

B. Nesse período, a maios parte dos artigos tentará explicar os resultados como erro metodológico do OPERA.

C. Nesse período, a maior parte dos papers  tentará compatibilizar, usando idéias próprias dos autores, os resultados do OPERA com a Relatividade, em vez de assumir quebra de invariância de Lorentz (estão excluídos aqui os papers do item B, ou seja, tentarão explicar as medidas, assumidas como corretas, usando-se diversas ideias que não erros sistemáticos do OPERA).

Bom, a minha aposta é no item A.

Eu vou também chutar aqui uma ideia (que não é minha): Devido as interações das partículas com o vácuo quântico, cada tipo de partícula tem uma velocidade limite c_i, por exemplo c_gamma = c,  c_proton, c_eletron, c_neutrino etc, todas muito proximas mas nao exatamente iguais.

Dai fica a pergunta: quais sao as evidencias e experimentos que realmente constrangem |c-c_i| < epsilon_i, e quanto vale epsilon_i experimentalmente para cada partícula? Putz, acho que essa ideia dá um paper!

Sim, eu sei que isso é anátema e heresia para os relativistas. A física teórica perderia sua beleza, não poderíamos mais fazer c =1 nas nossas equações etc. OK, OK, sim… é isso que se chama de “quebra de paradigma” na epistemologia de Thomas Kunh…  E percebem porque foi tão difícil para o pessoal abandonar o conceito de éter e a visão newtoniana (que tinha durado 300 anos!).

Se idéias extraordinárias precisam de evidências extraordinárias, então a Relatividade Geral só deveria ter sido aceita em 1960, por que as evidências anteriores (especialmente as do desvio da luz estelar perto do Sol) não eram nada extraordinárias, mas sim cheias de erros e ruído…

Nove papers no ArXiv sobre neutrinos superluminais

Só falta um para eu ganhar a aposta!

Lista no ArXiv Blog:

New Constraints On Neutrino Velocities

Superluminal Neutrinos Without Revolution

On the Possibility of Superluminal Neutrino Propagation

The Hypothesis of Superluminal Neutrinos: comparing OPERA with other Data

Relativistic Superluminal Neutrinos

The OPERA Neutrino Velocity Result And The Synchronisation Of Clocks

A Possible Statistical Mechanism Of Anomalous Neutrino Velocity In OPERA Experiment?

A Comment On The OPERA Result And CPT

Superluminal Neutrinos And Extra Dimensions: Constraints From The Null Energy Condition

Extensões do Modelo Padrão com Quebra de simetria de Lorentz e neutrinos superluminais

Standard-Model Extension

From Wikipedia, the free encyclopedia

Standard-Model Extension (SME) is an effective field theory that contains the Standard ModelGeneral Relativity, and all possible operators that break Lorentz symmetry.[1][2][3][4][5][6][7][8] Violations of this fundamental symmetry can be studied within this general framework. CPT violation implies the breaking of Lorentz symmetry,[9] and the SME includes operators that both break and preserve CPT symmetry.[10][11][12]

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[edit]Development

In 1989, Alan Kostelecký and Stuart Samuel proved that interactions in string theories could lead to the spontaneous breaking of Lorentz symmetry.[13] Later studies have indicated that loop-quantum gravity, non-commutative field theories, brane-world scenarios, and random dynamics models also involve the breakdown of Lorentz invariance.[14] Interest in Lorentz violation has grown rapidly in the last decades because it can arise in these and other candidate theories for quantum gravity. In the early 1990s, it was shown in the context of bosonicsuperstrings that string interactions can also spontaneously break CPT symmetry. This work[15] suggested that experiments with kaon interferometry would be promising for seeking possible signals of CPT violation due to their high sensitivity.

The SME was conceived to facilitate experimental investigations of Lorentz and CPT symmetry, given the theoretical motivation for violation of these symmetries. An initial step, in 1995, was the introduction of effective interactions.[16][17] Although Lorentz-breaking interactions are motivated by constructs such as string theory, the low-energy effective action appearing in the SME is independent of the underlying theory. Each term in the effective theory involves the expectation of a tensor field in the underlying theory. These coefficients are small due to Planck-scale suppression, and in principle are measurable in experiments. The first case considered the mixing of neutral mesons, because their interferometric nature makes them highly sensitive to suppressed effects.

In 1997 and 1998, two papers by Don Colladay and Alan Kostelecký gave birth to the minimal SME in flat spacetime.[1][2] This provided a framework for Lorentz violation across the spectrum of standard-model particles, and provided information about types of signals for potential new experimental searches.[18][19][20][21][22]

In 2004, the leading Lorentz-breaking terms in curved spacetimes were published,[3] thereby completing the picture for the minimal SME. In 1999, Sidney Coleman and Sheldon Glashowpresented a special isotropic limit of the SME.[23] Higher-order Lorentz violating terms have been studied in various contexts, including electrodynamics.[24]

[edit]Lorentz transformations: observer vs. particle

Lorentz violation implies a measurable difference between two systems differing only by a particle Lorentz transformation. The distinction between particle and observer transformations is essential to understanding Lorentz violation in physics.

In special relativity, observer Lorentz transformations relate measurements made in reference frames with differing velocities and orientations. The coordinates in the one system are related to those in the other by an observer Lorentz transformation — a rotation, a boost, or a combination of both. Both observers will agree on the laws of physics, since this transformation is simply a change of coordinates. On the other hand, identical experiments can be rotated or boosted relative to each other, while being studied by the same inertial observer. These transformations are called particle transformations, because the matter and fields of the experiment are physically transformed into the new configuration.

In a conventional vacuum, observer and particle transformations can be related to each other in a simple way—basically one is the inverse of the other. This apparent equivalence is often expressed using the terminology of active and passive transformations. The equivalence fails in Lorentz-violating theories, however, because fixed background fields are the source of the symmetry breaking. These background fields are tensor-like quantities, creating preferred directions and boost-dependent effects. The fields extend over all space and time, and are essentially frozen. When an experiment sensitive to one of the background fields is rotated or boosted, i.e. particle transformed, the background fields remain unchanged, and measurable effects are possible. Observer Lorentz symmetry is expected for all theories, including Lorentz violating ones, since a change in the coordinates cannot affect the physics. This invariance is implemented in field theories by writing a scalar lagrangian, with properly contracted spacetime indices. Particle Lorentz breaking enters if the theory includes fixed SME background fields filling the universe.

[edit]Building the SME

The SME can be expressed as a lagrangian with various terms. Each Lorentz-violating term is an observer scalar constructed by contracting standard field operators with controlling coefficients called coefficients for Lorentz violation. Notice that these are not parameters of the theory, since they can in principle be measured by appropriate experiments. The coefficients are expected to be small because of the Planck-scale suppression, so perturbative methods are appropriate. In some cases, other suppression mechanisms could mask large Lorentz violations. For instance, large violations that may exist in gravity could have gone undetected so far because of couplings with weak gravitational fields.[25] Stability and causality of the theory have been studied in detail.[26]

[edit]Spontaneous Lorentz symmetry breaking

In field theory, there are two possible ways to implement the breaking of a symmetry: explicit and spontaneous. A key result in the formal theory of Lorentz violation, published byKostelecký in 2004, is that explicit Lorentz violation leads to incompatibility of the Bianchi identities with the covariant conservation laws for the energy-momentum and spin-density tensors, whereas spontaneous Lorentz breaking evades this difficulty.[3] This theorem requires that any breaking of Lorentz symmetry must be dynamical. Formal studies of the possible causes of the breakdown of Lorentz symmetry include investigations of the fate of the expected Nambu-Goldstone modes. Goldstone’s theorem implies that the spontaneous breaking must be accompanied by massless bosons. These modes might be identified with the photon,[27] the graviton,[28][29] spin-dependent interactions,[30] and spin-independent interactions.[25]

[edit]Experimental searches

The possible signals of Lorentz violation in any experiment can be calculated from the SME.[31][32][33][34][35][36] It has therefore proven to be a remarkable tool in the search for Lorentz violation across the landscape of experimental physics. Up until the present, experimental results have taken the form of upper bounds on the SME coefficients. Since the results will be numerically different for different inertial reference frames, the standard frame adopted for reporting results is the Sun-centered frame. This frame is a practical and appropriate choice, since it is accessible and inertial on the time scale of hundreds of years.

Typical experiments seek couplings between the background fields and various particle properties such as spin, or propagation direction. One of the key signals of Lorentz violation arises because experiments on Earth are unavoidably rotating and revolving relative to the Sun-centered frame. These motions lead to both annual and sidereal variations of the measured coefficients for Lorentz violation. Since the translational motion of the Earth around the Sun is nonrelativistic, annual variations are typically suppressed by a factor 10−4. This makes sidereal variations the leading time-dependent effect to look for in experimental data.[37]
Measurements of SME coefficients have been done with experiments involving:

All experimental results for SME coefficients are tabulated in the Data Tables for Lorentz and CPT Violation.[38]

[edit]External links

[edit]See also

Neutrinos superluminais: Aposta fechada com Jorge Stolfi da UNICAMP!

JorgeStolfi Jorge Stolfi

@
@osamekinouchi O que eu quero dizer é que é muito difícil enxergar os erros em seu próprio trabalho.
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi Cena que já vi muitas vezes: “Prof, faz dois dias que procuro o bug neste programa! Começo fazendo… ah! Achei!”
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi Topo. Até a vista…
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi Não, eu sou computeiro.
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi Eu aposto uma pizza que a distância (provavelmente) ou tempo estão errados. Em que cidade vocẽ mora?
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi De fato. 😎 Mas a profissão de cientista obriga a procurar cuidadosamente erros experimentais, nossos ou dos outros.
Jorge Stolfi

JorgeStolfi Jorge Stolfi

@
@osamekinouchi Gozado como físicos só discutem como corrigir Einstein, em vez de analisar se a medida da distância está correta.
Bê Neviani

Be_neviani Bê Neviani

@
Ainda sobre o bolão dos neutrinos t.co/6JDL6e3C rt@osamekinouchi //#ueba e c/participação especial do@universofisico #twitciencia
osamekinouchi
osamekinouchi osamekinouchi
A verdade está na fora: ArXiv.orgsemciencia.haaan.com/?p=1135
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Ou seja, a explicacao tipo Navalha de Occam nao será trivial. E a teoria de inferencia estatistica diz que a Navalha falha…
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Jorge, eu acho que qualquer explicacao nao será facil pois os caras sao bons e procuraram por 6 meses por erros sistematicos
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Ou seja, a explicacao tipo Navalha de Occam nao será trivial. E a teoria de inferencia estatistica diz que a Navalha falha…
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Jorge, eu acho que qualquer explicacao nao será facil pois os caras sao bons e procuraram por 6 meses por erros sistematicos
osamekinouchi
osamekinouchi osamekinouchi
@JorgeStolfi O comentarista supos que neutrinos interagiriam fracamente pares virtuais, de modo que c<c´<C onde c´=velocidade dos neutrinos
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Eu gostei da ideia de que a luz interage com os pares eletron-positron virtuais de modo que c < C, onde C é a velocidade limite
osamekinouchi
osamekinouchi osamekinouchi
@JorgeStolfi Já sei! Me convide para dar um talk sobre o indice de Garfield-Hirsch, que é bem melhor que o indice de Hirsch!
osamekinouchi
osamekinouchi osamekinouchi
@JorgeStolfi Vc é quimico, nao? Eu sou amigo do Sergio Galembeck. Devo ir para campinas até o final do ano…
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Ribeirao Preto: Eu aceito, mas tem que ser uma pizza + um kit de cervejas Colorado (R$ 40,00)
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi Jorge, acho que agora a questao é se o efeito é real, uma verdadeira anomalia ou apenas um erro sistematico.
osamekinouchi
osamekinouchi osamekinouchi

@
@JorgeStolfi As for me, I have just enough confidence about the multiverse to bet the lives of both Andrei Linde and Martin Rees’s dog.“
osamekinouchi
osamekinouchi osamekinouchi
Martin Rees said that he was sufficiently confident about the multiverse to bet his dog’s life while Linde said he would bet his own life
osamekinouchi
osamekinouchi osamekinouchi
@JorgeStolfi Weinberg em Living in the Multiverse: “He said it: A truly committed scientist will bet just about anything …”
osamekinouchi
osamekinouchi osamekinouchi
@JorgeStolfi A medida da sua crença ou ceticismo é dada por quanto você está disposto a apostar… rs R$ 100 nao é muito!

Ainda sobre o bolão dos neutrinos

Olá Osame,
Sou avesso a apostas e bolões : – ) Não participo nem em Copa do Mundo. Mas vou confessar que torço para que o sinal do OPERA revele-se um erro sistemático ou, se for mesmo confirmado, alguém apareça com uma explicação MUITO boa que acabe salvando o princípio da causalidade.
Abraços,
Igor

  • okinouchi disse:

    Igor,

    Não sei por que mas acho que a comunidade anda muito conservadora. Por anos ficamos reclamando que a física anda muito parada, que não há nada de novo, que seria legal o LHC começar logo a revelar “física nova”. Mas física nova, por definição, é a física que abala e mesmo muda o paradigma anterior.

    Eu vejo as pessoas se comportarem como Lorentz que, mesmo a trasnformação tendo o seu nome, nao aceitou a relatividade e acreditou no eter até o final da vida.

    Eu gostei do comentario de um dos caras acima, em que ele propoe que, dado que fótons interagem com os pares eletron-positrons virtuais, ou seja, dado que o vácuo quantico (nao previsto pela Relatividade) se comporta como um dielétrico, a luz teria uma velocidade na verdade um pouco menor de a velocidade limite C (vamos usar C maiusculo e reservar c minusculo para a medida da velocidade da luz em laboratorio, OK?).

    Já no caso dos neutrinos, eles nao interagiriam com os pares eletron-pósitrons, de forma que sua velocidade estaria proxima de C (mesmo levando em conta que eles possuem massa nao nula).

    Me explica uma coisa: em teoria de campo, os neutrinos sao descritos por um campo spinorial? Eles seguem a equação de Dirac? Ou é melhor descrever em termos de segunda quantização? Mas de que tipo de campo? Ainda um campo spinorial de spin 1/2 ?

    Outra duvida: Com quantas casas decimais se pode medir a velocidade da luz c antes que as correcoes quanticas via interacao com os pares virtuais se façam sentir? Se a constante c for universal, isso significa que eu posso medir infinitas casas decimais (ou seja, é um problema apenas de tecnologia de medição?). Ou existe um limite fundamental para o numero de casas decimais que se pode medir nas constantes fisicas (ao contrario das constantes matematicas tipo /pi)?

    Eu ouvi falar que a convenção de tomar c = 1 pode ser conveniente mas está, em termos fisicos, errada, pois supoe, por exemplo, que c(t) = c = cte a priori, e teoricamente isto nao é justificavel (por exemplo, a teoria VLS (variable light speed) de João Magueijo, que é a concorrente da teoria da Inflação, postula que não houve inflação no inicio do Big Bang mas apenas que c era muito maior no inicio do Universo… Ver o video sensacional: http://www.youtube.com/watch?v=ig-50Rz_Q1Q

     

    Por outro lado, se Einstein estivesse vivo hoje, acho que ele estaria super excitado, afinal ele reclamava que “Sempre gostei de contestar autoridades, e a vida, para me punir, me tornou uma”… ou algo assim, estou lembrando a citação de cabeça…

    Dado que voce comentou, eu imagino que você optou pelo item B. Neste caso, veremos o resultado no dia 21 de dezembro deste ano, OK?

    Usarei os R$ 100 seus para me ajudar a comprar o telescópio que meus filhos me pediram…

Standard-Model Extension

From Wikipedia, the free encyclopedia

Standard-Model Extension (SME) is an effective field theory that contains the Standard ModelGeneral Relativity, and all possible operators that break Lorentz symmetry.[1][2][3][4][5][6][7][8] Violations of this fundamental symmetry can be studied within this general framework. CPT violation implies the breaking of Lorentz symmetry,[9] and the SME includes operators that both break and preserve CPT symmetry.[10][11][12]

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Corrida entre neutrinos e fótons: quem topa participar do bolão?

Pessoal,

Estou fazendo um bolão aqui com as seguintes regras, sobre os resultados dos neurtrinos mais rápidos que a luz do OPERA. Se você concorda, assine nos comentários (não vale assinar anônimo!).

A. Haverá consenso (positivo) sobre os resultados do OPERA até 21 de dezembro de 2011.

B. Haverá consenso (negativo) sobre os resultados do OPERA até 21 de dezembro de 2011.

C. Um monte de teóricos vão publicar sobre neutrinos hiperluminais no ARXIV até 21 de dezembro de 2011, com um mínimo de 10 papers.

PS:  Consenso significará o reconhecimento pela comunidade (não por todos, é claro!) que o efeito é real (não é devido a erro sistemático nas medidas) e necessita explicação.

Escolha a sua opção (A, B ou C). O premio do bolão será dividido entre os que tiverem a mesma opinião vencedora. A minha opinião é C para 21 de dezembro de 2011 e A se o prazo for estendido para 21 de dezembro de 2012.

Published online 22 September 2011 | Nature | doi:10.1038/news.2011.554
Updated online: 23 September 2011

News

Particles break light-speed limit

Neutrino results challenge cornerstone of modern physics.

Geoff Brumfiel

Has OPERA found super-speedy neutrinos?CERN

An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics — that nothing travels faster than 299,792,458 metres per second. [Se os resultados do OPERA estiverem corretos, então os neutrinos viajam a cerca de 299.794.000 metros por segundo.

The experiment is called OPERA (Oscillation Project with Emulsion-tRacking Apparatus), and lies 1,400 metres underground in the Gran Sasso National Laboratory in Italy. It is designed to study a beam of neutrinos coming from CERN, Europe’s premier high-energy physics laboratory located 730 kilometres away near Geneva, Switzerland. Neutrinos are fundamental particles that are electrically neutral, rarely interact with other matter, and have a vanishingly small mass. But they are all around us — the Sun produces so many neutrinos as a by-product of nuclear reactions that many billions pass through your eye every second.

The 1,800-tonne OPERA detector is a complex array of electronics and photographic emulsion plates, but the new result is simple — the neutrinos are arriving 60 nanoseconds faster than the speed of light allows. “We are shocked,” says Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA’s spokesman.

Breaking the law

The idea that nothing can travel faster than light in a vacuum is the cornerstone of Albert Einstein’s special theory of relativity, which itself forms the foundation of modern physics. If neutrinos are travelling faster than light speed, then one of the most fundamental assumptions of science — that the rules of physics are the same for all observers — would be invalidated. “If it’s true, then it’s truly extraordinary,” says John Ellis, a theoretical physicist at CERN.

Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometre trip between CERN and its detector to within 20 centimetres. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma — the physicists’ way of saying it is certainly correct. The group will present their results tomorrow at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.

At least one other experiment has seen a similar effect before, albeit with a much lower confidence level. In 2007, the Main Injector Neutrino Oscillation Search (MINOS) experiment in Minnesota saw neutrinos from the particle-physics facility Fermilab in Illinois arriving slightly ahead of schedule. At the time, the MINOS team downplayed the result, in part because there was too much uncertainty in the detector’s exact position to be sure of its significance, says Jenny Thomas, a spokeswoman for the experiment. Thomas says that MINOS was already planning more accurate follow-up experiments before the latest OPERA result. “I’m hoping that we could get that going and make a measurement in a year or two,” she says.

Reasonable doubt

If MINOS were to confirm OPERA’s find, the consequences would be enormous. “If you give up the speed of light, then the construction of special relativity falls down,” says Antonino Zichichi, a theoretical physicist and emeritus professor at the University of Bologna, Italy. Zichichi speculates that the ‘superluminal’ neutrinos detected by OPERA could be slipping through extra dimensions in space, as predicted by theories such as string theory.

Ellis, however, remains sceptical. Many experiments have looked for particles travelling faster than light speed in the past and have come up empty-handed, he says. Most troubling for OPERA is a separate analysis of a pulse of neutrinos from a nearby supernova known as 1987a. If the speeds seen by OPERA were achievable by all neutrinos, then the pulse from the supernova would have shown up years earlier than the exploding star’s flash of light; instead, they arrived within hours of each other. “It’s difficult to reconcile with what OPERA is seeing,” Ellis says.

Ereditato says that he welcomes scepticism from outsiders, but adds that the researchers have been unable to find any other explanation for their remarkable result. “Whenever you are in these conditions, then you have to go to the community,” he says.

UPDATED:

The OPERA collaboration has posted a paper describing their result.

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‘Ficção Científica é maneira mais simples de gerar interesse na ciência’, diz o físico Michio Kaku

11/05/2011 06h45 – Atualizado em 11/05/2011 08h21

Há 150 anos, ao imaginar como seria a viagem do homem à Lua, o escritor Júlio Verne acertou quase na mosca três palpites: o primeiro voo sairia do estado norte-americano da Flórida, demoraria três dias para chegar ao destino e cairia no mar ao voltar à Terra. Tentando seguir seus passos, o físico teórico Michio Kaku também tenta adivinhar como ideias vindas da ficção científica, como colonizar galáxias distantes, seriam possíveis.

“O nosso desafio é mostrar para as pessoas como os conceitos científicos que vão governar o futuro no espaço podem ser compreendidos hoje mesmo, por qualquer pessoa”, afirma o cientista norte-americano de 64 anos, cocriador da teoria das cordas — agora, apresentador do programa “Física do Impossível”, no canal de TV a cabo Discovery Science.

“A ficção talvez seja a maneira mais simples de fazer as pessoas se interessarem por ciência”, afirma Kaku.

Michio Kaku 2 (Foto: Discovery / Divulgação)O físico Michio Kaku, apresentador do ‘Física do Impossível’. (Foto: Discovery / Divulgação)

Especializado em teoria das cordas – campo da física que enxerga os átomos como se fossem “fios” extremamente pequenos e oferece uma nova interpretação para como o espaço e as coisas se comportam -, o cientista usa o conhecimento disponível atualmente no mundo da física e tenta aplicá-los para explicar como seria possível captar mais energia das estrelas ou mesmo povoar o espaço.

Ao ser lembrado sobre como ideias como essas parecem estar distantes da realidade, Kaku cita o exemplo de Verne. Para o cientista, o escritor não contava com o dom de premonição e mostrou como ideias estranhas durante uma época podem apontar corretamente o futuro.

“Como ele conseguiu saber tudo isso? Não pode ser pura especulação. Ele conversava com cientistas e conseguiu, com o conhecimento da época, enxergar algo que parecia improvável”, afirma.

O ‘futuro’ nas crianças
Muito antes da fama de séries como ‘Jornada nas estrelas’ e ‘Guerra nas estrelas’, o físico norte-americano iniciou seu contato com ciência por meio de outra atração na TV: Flash Gordon, um dos primeiros herois espaciais.

“Foi a primeira vez que eu me interessei por naves, invisibilidade, aliens e viagens espaciais”, lembra o físico. A partir daí, Kaku nunca mais deixaria de espantar “como uma criança” e seguiria o caminho até virar um cientista profissional. Read more [+]

Pode a a massa gravitacional de anti-partículas ser o negativo de sua massa inercial?

Bom, se isso for verdade, o princípio da equivalência cai por terra, junto com a Relatividade Geral… Ou não?

If gravity repels antimatter, then the generation of neutrino telescopes now being built could spot the tell tale sign.

When it comes to antimatter, physicists have an embarrassing problem. Ask them whether a lump of the stuff would fall to Earth or be repelled by it, they’ll shuffle their feet and stare at their shoes.

The truth is that nobody knows; and not for lack of trying. Various attempts to drop antimatter and see where it goes have all been inconclusive.

But the mystery could now be solved by a latecomer to the field of antimatter research. Today, Dragan Hajdukovic, a physicist at CERN near Geneva, says that the current generation observatories designed to see neutrinos could answer this question.

And he takes an unconventional view of things. He points out that particle-antiparticle pairs are constantly leaping in and out of existence in any field sufficiently strong to allow this phenomenon.

Normally, gravity is too weak to support this process. However, he says that all changes inside a black hole where field strengths reach extraordinary values. Here, Hajdukovic calculates that the field ought to be strong enough to generate a regular stream of neutrino-antineutrino pairs.

If gravity attracts both matter and antimatter, then we’ll be none the wiser since matter can never escape from a black hole and we’d never see either of these particles.

But if gravity repels antimatter, the antineutrinos would be hurled out of the black hole with great energy. “While neutrinos must stay confined inside the horizon, the antineutrinos should be violently ejected,” says Hajdukovic,

That would make black holes powerful antineutrino sources. Hajdukovic calculates that the supermassive black holes at the centre of the Milky Way and Andromeda galaxies should be bright enough to be seen by the generation of the neutrino telescopes currently being built.

The biggest and most sensitive of these is IceCube, a detector currently being assembled in the ice beneath the South Pole. It should be complete next year.

Hajdukovic gives one caveat, however. He says that the discovery of antineutrinos streaming from black holes would not automatically settle the question of which way antimatter falls. The reason is that another previously unknown force may have generated the neutrino antineutrino pairs inside the balck hole. That’ll require further investigation.

Either way, that’d be a mighty interesting discovery. Let’s hope the guys at IceCube have their hi-tech lens cloths at the the ready.

Ref: arxiv.org/abs/0710.4316: Can The New Neutrino Telescopes Reveal The Gravitational Properties Of Antimatter?