Physics experiment suggests existence of new particle

Nov 02, 2010

(PhysOrg.com) -- The results of a high-profile Fermilab physics experiment involving a University of Michigan professor appear to confirm strange 20-year-old findings that poke holes in the standard model, suggesting the existence of a new elementary particle: a fourth flavor of neutrino.

The new results go further to describe a violation of a fundamental symmetry of the universe asserting that particles of antimatter behave in the same way as their matter counterparts.

Neutrinos are neutral born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation."

An electron neutrino might become a muon neutrino, and then later an electron neutrino again. Scientists previously believed three flavors of neutrino exist. In this Mini Booster Neutrino Experiment, dubbed MiniBooNE, researchers detected more oscillations than would be possible if there were only three flavors.

"These results imply that there are either new particles or forces we had not previously imagined," said Byron Roe, professor emeritus in the Department of Physics, and an author of a paper on the results newly published online in .

"The simplest explanation involves adding new neutrino-like particles, or sterile neutrinos, which do not have the normal weak interactions."

The three known types of neutrino interact with matter primarily through the weak nuclear force, which makes them difficult to detect. It is hypothesized that this fourth flavor would not interact through the weak force, making it even harder to find.

The existence of sterile neutrinos could help explain the composition of the universe, said William Louis, a scientist at Los Alamos National Laboratory who was a doctoral student of Roe's at U-M and is involved in the MiniBooNE experiment.

"Physicists and astronomers are looking for sterile neutrinos because they could explain some or even all of the dark matter of the universe," Louis said. "Sterile neutrinos could also possibly help explain the matter asymmetry of the universe, or why the universe is primarily composed of matter, rather than antimatter."

The MiniBooNE experiment, a collaboration among some 60 researchers at several institutions, was conducted at Fermilab to check the results of the Liquid Scintillator Neutrino Detector (LSND) experiment at Los Alamos National Laboratory, which started in 1990. The LSND was the first to detect more neutrino oscillations than the predicted.

MiniBooNE's initial results several years ago, based on data from a neutrino beam (as opposed to an antineutrino beam), did not support the LSND results. The LSND experiment was conducted using an antineutrino beam, though, so that was the next step for MiniBooNE.

These new results are based on the first three years of data from an antineutrino beam, and they tell a different story than the earlier results. MiniBooNE's antineutrino beam data does support the LSND findings. And the fact that the MiniBooNE experiments produced different results for antineutrinos than for neutrinos especially astounds physicists.

"The fact that we see this effect in antineutrinos and not in neutrinos makes it even more strange," Roe said. "This result means even more serious additions to our standard model would be necessary than had been thought from the first LSND result."

The result seems to violate the "charge-parity symmetry" of the universe, which asserts that the laws of physics apply in the same ways to particles and their counterpart antiparticles. Violations of this symmetry have been seen in some rare decays, but not with , Roe said.

While these results are statistically significant and do support the LSND findings, the researchers caution that they need results over longer periods of time, or additional experiments before physicists can rule out the predictions of the standard model.

Explore further: Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field

More information:
-- The paper is called "Event Excess in the MiniBooNE Search for ν̅ μ→ν̅ e Oscillations." It will be published in an upcoming edition of Physical Review Letters. prl.aps.org/abstract/PRL/v105/i18/e181801
-- MiniBooNE: www-boone.fnal.gov/index.html

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User comments : 34

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deatopmg
1.8 / 5 (21) Nov 02, 2010
Here comes yet another phantasmagorical patch, AKA; fudge factor, for the SM. When will enough be enough?
KISS
genastropsychicallst
1.3 / 5 (13) Nov 02, 2010
... particle edenanti ...
A2G
1.7 / 5 (38) Nov 02, 2010
The standard model is dead. When are those doing the research going to finally realize that it is? I have never seen a more religious group of people in my life. Belief in the SM is now about faith, not science.
jsa09
4.5 / 5 (6) Nov 02, 2010
I hope it does not take another 20 years to get further confirmation of these results. I am not sure I will live that long or retain my interest.
Noumenon
3.2 / 5 (14) Nov 02, 2010
If the standard model where dead it won't be the standard model, now would it.
Nik_2213
2.7 / 5 (3) Nov 02, 2010
How weird !! Uh, won't this affect supernova explosions, those 'standard candles' for intergalactic distances ??
eachus
4.4 / 5 (25) Nov 02, 2010
The standard model is dead. When are those doing the research going to finally realize that it is? I have never seen a more religious group of people in my life. Belief in the SM is now about faith, not science.


Sigh! You have to understand how science works. There is always a standard model. Experimentalists test their data against the (current) SM, and theorists propose extensions or tweaks to the standard model based on the experimental data.

Eventually fit between data and theory is strong enough, and new theory is added into the SM. It may replace or augment the existing theory. Now experimentalists test against the NEW standard model, and physics proceeds.

The thing to watch for are improvements to the SM that reduce or eliminate the large number of 'free' parameters in the model. These are numbers selected for no other reason than their fit to the data. Eliminating just one free parameter from the model is probably worth a Nobel Prize.
Tangent2
1.6 / 5 (17) Nov 02, 2010
I would have to agree with the majority here, it looks like we are just too keen on patching up the standard model that a rethink about particle physics isn't even considered. It's like taking an old boat that has been patched up all over out on the water and hoping it holds together.. and it would.. just barely, but that is not good enough to be incorporated into a theory of everything.
Ravenrant
2.8 / 5 (10) Nov 02, 2010
We worship a lot of false or near gods and Einstein is one of them. He was right about almost everything, ALMOST, he wasn't and isn't infallible and yet most scientists have more faith in his theories than the devout have in the bible. I am sure he was wrong about a few things. We need to stop worshiping his theories and start questioning more.
Bonkers
4 / 5 (11) Nov 02, 2010
Guys, you're missing the point, the Standard Model is a largely empirical best-fit to the data, it defines what we observe. New verified data like a sterile neutrino needs an extension built for it - ugly but accurate.
Given this behavioural model, the theoretical physicists have a datum they can measure up to.
We are all waiting for the (presumed) elegant theory that matches the SM with fewer arbitrary parameters, and for the insight that would bring. Top contender is a version of supersymmetry, but the additional dimensions it brings are extraordinary, containing the fabric to (IMO) support paraphysics, intelligence, soul - and therefore requires extraordinary evidence.
Question
not rated yet Nov 02, 2010
What are the differences they kept referring to in this article? Numbers please.
Slotin
1.3 / 5 (29) Nov 02, 2010
The existence of another generation of particles is logical in fractal model of Universe, composed of nested fluctuations like every dense particle gas. After all, some indicia of fourth generation of quarks was revealed recently - so why not search for fourth generation of neutrino?

http://arxiv.org/.../9603436

http://www.scienc..._go_away
Slotin
1.2 / 5 (19) Nov 02, 2010
The existence of fourth generation of particles actually violates the concept of Higgs field - if nothing else, we are forced to search for even more massive scalar field corresponding the newly revealed fourth generation of quarks and neutrinos. Which makes the concept of distinct rest mass of Higgs boson somewhat illusive, indeed... I'd recommend to read just this article in this connection:

http://www.physor...225.html
HaveYouConsidered
4.5 / 5 (2) Nov 02, 2010
I am not close enough to the details of the physics to know for certain, but this news is perhaps interesting in terms of supporting Heim Theory as an alternative to the SM. It is, after all, the only alternative that has some success at predicting (quite accurately) particle masses from fundamental constants, something SM does not do, since SM requires masses to be "plugged in" empirically.

But HT also predicts the existence of a (so far unseen) neutral electron. If new neutrinos are turning up, perhaps the neutral electron will also.
Slotin
1.2 / 5 (26) Nov 02, 2010
The standard model is dead. Belief in the SM is now about faith, not science.
Theories aren't dead, until better model is found - they're just becoming more and more approximative. There are many extensions of SM, which can handle fourth generation of particles, they've even their own shortcuts (SM4, SM4+D).

http://link.aps.o...2.033009
http://arxiv.org/abs/1004.3464

The more then twenty constants of SM are making it sufficiently flexible for most of theorists, who are looking for continuity in jobs and professional carriers. I'd recommend you to become familiar with streetlight effect before prognosing urgent death of SM.

http://discoverma...t-effect
poktopok
4.8 / 5 (9) Nov 02, 2010
We worship a lot of false or near gods and Einstein is one of them. He was right about almost everything, ALMOST, he wasn't and isn't infallible and yet most scientists have more faith in his theories than the devout have in the bible. I am sure he was wrong about a few things. We need to stop worshiping his theories and start questioning more.


Einstein didn't come up with the Standard Model... in fact, the creation of the Standard Model was a purely collaborative effort, honed over dozens of years by many scientists.
Crackpot
2 / 5 (8) Nov 02, 2010
Fair enough that people still have faith in the standard model, but why this model by default is regarded superior to any other hypothesis seems strange to me. If other ideas simplifies things they deserve a glance ...

http://classicala...pot.com/
StandingBear
1.6 / 5 (10) Nov 02, 2010
new fundamental forces anyone.....or is that against the religion of Einstein......who knows maybe gravity is subject to permutations of the new and old forces. We know that some machines our government in concert with others deny.......really DO exist. They must use ...SOME ...principle of operation. Who knows, the SM may have a third dimension, and that would open a real bucket of worms for todays dogmaticists.
skajam66
5 / 5 (1) Nov 03, 2010
This appears to be contrary to results produced by the very same experiment in 2007, no?
marcin_szczurowski
2 / 5 (7) Nov 03, 2010
It all begin to look like the theory of epicycles. We don't know much but let's try to patch current not-working model for which everybody agreed.

http://xkcd.com/812/

IMO SM is even more hopeless than dark matter.
I wonder if we'll be ever capable of explaining the matter itself. Several years ago, professor that taught me basics of particle physics asked us to think which is more terrifying - to be able to divide matter infinitely or to reach solid, smooth surface at some point. We won't get anywhere close to answers if we stick to theories that obviously don't work. Methinks :P
Slotin
1.2 / 5 (21) Nov 03, 2010
Standard Model is merely a qualified regression of microscopic reality. Regressions are always approximate - on the other hand, they cannot be wrong, if they're handled like regressions. Can be equation of line wrong? It's simply a linearisation of more complex problem. If such line fits the model at least at certain range and simplifies its solution, where's the problem?

Many connections are misunderstood even by professional physicists. For example, it's generally believed, Standard Model requires the existence of Higgs boson and if we wouldn't find the Higgs boson at LHC, it would mean, SM is "wrong".

But the true is, Standard Model cannot predict/derive the rest mass of Higgs boson anyway - which means at the case of formal model (as SM undeniably is), it cannot plug it into any equation, being invariant/orthogonal to its actual value.

Why some theory should fall because we cannot find a particle, which such theory requires for anything?
Slotin
1.3 / 5 (22) Nov 03, 2010
From positivistic perspective the labelling of SM as "wrong" is ridiculous in the same way, like the saying, "the equation of line is wrong", because it doesn't fit some particular points properly. Theories cannot be wrong or right, when they're handled like approximations of reality, providing they're remain logical and consistent at formal level.

Stephen Hawking is saying in his new book, the future will use many theories, each of which will remain substantiated from its own perspective. Actually I presume, this is the multiverse, which string theorists are dreaming about.

http://www.time.c...,00.html

In my opinion, theories can be only homologies or analogies of reality. Analogies are always approximate at the quantitative level, but they're logically correct. Homologies can be exact to arbitrary degree of precision at their validity scope - but they're always wrong at logical level, as their agreement with reality is just a coincidence.
Slotin
1.5 / 5 (31) Nov 03, 2010
The pluralistic perspective of physical theories has actually it's deep socio-political application. You people are simply too testosterone driven and competitive. You can see only black and white, "good" and "bad" theories. The competition is the driving force of evolution, but after reaching of certain level it could serve like entropic force, instead.

For example, the Islamic people are fighting with western world for their oil and every part of this feud feels deeply justified in its stance. But hasn't each part of this feud its bit of truth in this fight? If we wouldn't admit it and if we wouldn't find a platform for mutual understanding and cooperation, we will all suffer the consequences.

I believe, the new generation of both physics, both humanity will not be based on authoritative selection of "good" or "wrong" theories, but on the understanding, how various theories and ideas are related mutually.
eachus
4.3 / 5 (6) Nov 06, 2010
I'm a statistician, so let me try to explain what goes on from that standpoint. In quantum mechanics, as a rough approximation, anything can happen. But the probability of most events is extremely low--including the 'signatures' of a particular massive particle that the teams running detectors look at.

So how do you determine whether or not you have seen a particular particle? You look at all the events you see--which may be lower than one in a billion collisions. Now compute how many events you would see if the standard model were true, but without the particle you are looking for, this is H_0 (aka the null hypothesis). Also compute the expectation with your new particle, or new theory. This is H_1.

There are various methods to compare H_0 and H_1, depending on the statistical test used. If the significance is high enough, you reject H_0 and accept H_1.

Notice that you always have to have a standard model to compare to. The (current) SM has changes when a particle is added.
genastropsychicallst
1 / 5 (4) Nov 06, 2010
L-boson.
MorituriMax
4.4 / 5 (7) Nov 06, 2010
The standard model is dead. When are those doing the research going to finally realize that it is? I have never seen a more religious group of people in my life. Belief in the SM is now about faith, not science.


Wow, another cliched turd drops from the mouths of people who just can't stand it when models need to be looked at and perhaps modified to reflect new information. No, let's just pronounce it dead from their ivory towers because then we sound smart and everyone else sounds dumb.

Care to show us what you're going to replace it with? And does your replacement model fare any better upon closer examination?
TheGhostofZephir
3 / 5 (4) Nov 06, 2010
TheWalrus
5 / 5 (1) Nov 07, 2010
Is anyone ever going to figure out what particles are "made of?" Yes, I know, E=MC^2 and all that. But let's say string theory or M theory turns out to be correct. What are the strings? It's not enough to say they're tiny, vibrating multidimensional loops of energy. Time and space are abstractions; relationships between things. So a string can't be just an abstract relationship; there needs to be actual things that have these relationships. If strings are just abstractions, then all possiblities would be equally real and would exist simultaneously. Since they do not, there must be something tangible, something actual.

Sorry, maybe the question is too fundamental to even be answerable. I'll slink off now...
Slotin
1 / 5 (5) Nov 07, 2010
Is anyone ever going to figure out what particles are "made of?
IMO they appear to be formed with nested density fluctuations of hypothetical infinitely dense inhomogeneous massive environment, like nested density fluctuations, which are formed during condensation of supercritical fluid - it's just much more, probably infinitely dense. Such fluid appears "stringy" too...

http://www.chem.l...co24.jpg
MorituriMax
5 / 5 (1) Nov 07, 2010
Hmm, tires no longer allow vehicles to move as easily when the ratio of inside/outside air pressure is 1:1. Hence, let it be known to all, the Standard Model of tires is DEAD!
Ober
1 / 5 (2) Nov 07, 2010
IMO perhaps the problem lies with the fact we threw out the AETHER (no this isn't a typical aether,plasma spam post) apx 150 years ago. I'm still intrigued by the following physorg article;
http://www.physor...ics.html

This article gives insights into wave-particle duality which makes sense. To me this seems like one of the holy grails of physics.

I suspect the SM needs to include the aether, and perhaps then the problems associated with approximations/pertubation theory will reduce or go away entirely.

Please read the link I provided on fluid dynamics and QM. It's truly an enlightening read. Try and keep this idea in the back of your head whenever you read QM articles.
Slotin
Nov 07, 2010
This comment has been removed by a moderator.
chandram
1 / 5 (4) Nov 08, 2010
Slotin's comments are the msot sensible of the lot. May i humbly add the costituents of dark and visible matter can only get reconciled if we treat both of these to originate from the primordial matter. If we assume that the primodrdial matter consisted of very heavy quarks that could decay under a very very strong field that existed then. Gradually this strong field decayed into our present strong field strength. At that stage the dark matter seperated from visible matter. The dark matter froze at that time with such heavy quarks while the visible matter got formed from the now known 6 quarks of which the lighter three gave rise to the nucleons and formed the visible matter. The dark matter got frozen with heavy quarks as strong field strength fell below a magnitude that could not affect their further decay any more.
chandram
1 / 5 (3) Nov 08, 2010
The above comments come from Narendra Nath with petname chandram. it will be appreciated if these comments receive some response.The begnning of the universe can only be conjectured as it is near impossible to conduct definite experiments for times closer to Big Bang, say for at least first billion years of its life. The earliest one has gone is to see light from the ealiest of galaxies formed after the first billion years! N. Nath
Skeptic_Heretic
5 / 5 (1) Nov 09, 2010
Dense aether theory of Oliver Lodge was never considered by mainstream physics. So we are just revealing it again... well, slowly.
Neither was the flat earth hypothesis of George Vaukler for the same reason. It was demonstrably wrong.
So a string can't be just an abstract relationship; there needs to be actual things that have these relationships. If strings are just abstractions, then all possiblities would be equally real and would exist simultaneously. Since they do not, there must be something tangible, something actual.
Well you're making a lot of statements that aren't provable. For example: "then all possiblities would be equally real and would exist simultaneously. Since they do not"

Prove that.

FYI: Chandram and Ober added to the list.