Rare particle decay could mean new physics

Aug 23, 2011 By Anne Ju

(PhysOrg.com) -- An incredibly rare sub-atomic particle decay might not be quite as rare as previously predicted, say Cornell researchers. This discovery, culled from a vast data set at the Collider Detector at Fermilab (CDF), is a clue for physicists trying to catch glimpses of how the universe began.

The work, which is generating buzz because of its possible implications for the existence of new physics, has been submitted to by an international team of scientists, among them Julia Thom-Levy, Cornell assistant professor of physics, and graduate student Walter Hopkins. The paper is available on arXiv.

Thom-Levy studies the decay of particles formed in high-energy collisions, with particular focus on a class of particles called strange B-mesons that consist of a beauty quark bound to a strange quark. The of Physics predicts the rate of strange B-mesons decaying into a pair of oppositely charged as exceedingly rare, with only a few decays out of 350 trillion collisions expected.

In the new data from Fermilab's , the researchers found four of these decays for every one expected. While the upward fluctuation could be a statistical fluke, it is attracting widespread attention in the field because it might possibly indicate the presence of new particles and lead to an entirely new model of physics.

Over the years, as scientists were able to collide more particles at higher energies, they were able to set upper limits on the probability of such decays. The Fermilab data set has allowed scientists to further narrow the probability of the rate of decay to be between 0.46 and 3.9 x 10-9.

One possible explanation for the observed excess is the existence of supersymmetric particles, for which no evidence yet exists, but which can help explain the origin of , which makes up about one fourth of the universe.

"So this could mean an excess, and it could mean the presence of new particles, but what is needed is a lot more data to really have enough numbers to constrain this more strongly," Thom-Levy said.

Such a larger data set is being worked on now by scientists, including Thom-Levy, at the Large Hadron Collider at CERN, which runs at higher energies than the Tevatron and may eventually confirm the excess in the Fermilab data.

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More information: Search for B_s --> mu+mu- and B_d --> mu+mu- Decays with CDF II, arXiv:1107.2304v1 [hep-ex] arxiv.org/abs/1107.2304v1

Abstract
A search has been performed for B_s --> mu+mu- and B_d --> mu+mu- decays using 7/fb of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B_d candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of BF(B_d-->mu+mu-) < 6.0E-9 at 95% confidence level. We observe an excess of B_s candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B_s --> mu+mu- could produce such an excess or larger is 1.9%. These data are used to determine BF(B_s-->mu+mu-) = (1.8^{+1.1}_{-0.9})E-8 and provide an upper limit of BF(B_s -->mu+mu-) < 4.0E-8 at 95% confidence level.

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User comments : 27

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albenza
4.1 / 5 (11) Aug 23, 2011
Funny. Just as we think we are about to understand what is going on, a new door opens, and we are baffled by the universe yet again.

We are still just learning to walk... Sad as it may seem, I think we still have a very long way to go, before we scratch the surface of how, where and what the universe really is. (That is assuming we ever will).
antialias_physorg
5 / 5 (13) Aug 23, 2011
Careful: 'new physics' doesn't automatically mean that all the 'old physics' is dead wrong...just that we're missing pieces.

Whether we are missing a little or a lot to get the whole picture is also pure speculation.
Mayday
1 / 5 (21) Aug 23, 2011
The history of science is so funny and also ironic.("ironical" is actually the right word, but it sounded too funny to type in) Over and over, new discoveries are made and we are greeted with a chorus of scientists rushing to defend their "belief" in the old "facts." Yet they shower unending disdain on people who "believe" in matters of spirit. Too bad one can't obtain a grant for practicing spirituality.

Wait for it...
PHANT0M PARTICLE
1.3 / 5 (16) Aug 23, 2011
God im soooo sick of hearing about " dark matter and "dark energy" why OH why dont the physicists just say " We dont know what is at work here ,when we figure it out we will give " it" a real name"
tkjtkj
4.7 / 5 (13) Aug 23, 2011
Too bad one can't obtain a grant for practicing spirituality.

Wait for it...


Please go spread your religious poppycock elsewhere ... where scientists refuse to tread ...

hard2grep
2.5 / 5 (2) Aug 23, 2011
I see preparedness on the part of waiting physicists. As it grows late in the higgs hunting season, they are realizing that there may be something in the numbers that suggests an alternate outcome. At least if we are wrong, then we still have a shot at figuring out gravity.
antialias_physorg
4.3 / 5 (8) Aug 23, 2011
dark matter and "dark energy" why OH why dont the physicists just say " We dont know what is at work here ,when we figure it out we will give " it" a real name"

because occasionally scintists have to talk to each other about observable efects - and then it#s god to have common terminology.

The term 'dark' already signifies that there doesn't yet exist a really a solid framework for either the energy/matter thus denoted.
For now we only know what it does (drives cosmic expansion, reates gavity lensing effects) and what it doesn't do (doesn't interact with ordinary matter/radiation)

You can count on it that when physicists figure out what these things really are (and there will probably more than the two categories as I suspect there will be an entire 'dark zoo') that they will be given other names.
Baseline
5 / 5 (19) Aug 23, 2011
The history of science is so funny and also ironic.("ironical" is actually the right word, but it sounded too funny to type in) Over and over, new discoveries are made and we are greeted with a chorus of scientists rushing to defend their "belief" in the old "facts." Yet they shower unending disdain on people who "believe" in matters of spirit. Too bad one can't obtain a grant for practicing spirituality.
he funds raised here have been keeping the world in darkness and reinforcing the
Wait for it...


You already have a process for that and it's been in place for a very long time it's called the collection plate. The money raised there has been keeping man in ignorance for centuries, no need for yet another mechanism for keeping us from progress.
fmfbrestel
4 / 5 (4) Aug 23, 2011
Another advancement of physics by an accelerator scheduled to be mothballed. Hope those scientists are preparing for their upcoming unemployment filing.
antialias_physorg
5 / 5 (9) Aug 23, 2011
Don't worry too much about the scientists. They have good qualifications and are versatile enough to be employable in a wide range of fields (scientific or at a company doing R&D).

Heck, I had twice the situation that a non-renewable contract ran out during my scientific career (three times if you count the time I got my degree at university) - each time I had to write a grand total of one job application to find something new and interesting to do. And I am probably just an average researcher in my field.
SteveL
1 / 5 (5) Aug 23, 2011
Sometimes (often) I check the stats in articles.
From the article: "but which can help explain the origin of dark matter, which makes up about one fourth of the universe."

Which matches up with "Dark matter makes up about 25%." from: http://science.na...-energy/ :

From Wikipedia http://en.wikiped...k_matter : "From these figures, dark matter constitutes 83%, (23/(23 4.6)), of the matter in the universe, whereas ordinary matter makes up only 17%."

I truly wish those who write informative articles to disseminate information to the masses would keep their information updated.
Jaeherys
not rated yet Aug 23, 2011
Dark matter makes up ~25% of the total energy but ~83% of the total matter.
fmfbrestel
5 / 5 (5) Aug 23, 2011
@antialias Good to know, but the point remains, we are shutting down a perfectly good facility which is still contributing cutting edge research. Cern might have a more powerful accelerator, but (if you forgive the analogy) having the most powerful telescope imaginable does not grant you enough time to scan the universe at full power. Being the second best does not imply having no value.
NameIsNotNick
5 / 5 (4) Aug 23, 2011

Wait for it...


Well what do you expect when you show such a complete ignorance of the scientific method.
wordofmouth
not rated yet Aug 23, 2011
I'm confident more new physics will come from crashing particles. If it's found that the higgs-bonson doesn't exist, this opens even bigger doors for exploration.
Vendicar_Decarian
3 / 5 (4) Aug 24, 2011
"Yet they shower unending disdain on people who "believe" in matters of spirit" - Foofa

Ya, those silly scientists and their silly scientific ways. When will they ever learn that Spiritualism has cured more diseases than they will ever cure.

Vendicar_Decarian
1 / 5 (2) Aug 24, 2011
"the point remains, we are shutting down a perfectly good facility which is still contributing cutting edge research." - fmf

America just can't afford to keep it running.
StarGazer2011
1 / 5 (1) Aug 24, 2011
'implied non em-interactive matter' would be a better term than 'dark matter' , its not dark, its transparent :) And at this point is just an artifact of an incomplete model, possibly it exists as WIMPS or MACHOS or possibly there are a range of new phenomena and adjustments to /replacements of theory required to explain observations.
StarGazer2011
3 / 5 (4) Aug 24, 2011
@Vendicar : Maybe if the USA decomissions a couple of stealth bombers, or I dunno ... stopped bailing out failed Wall St gamblers, they could afford something useful.
antialias_physorg
5 / 5 (2) Aug 24, 2011
Good to know, but the point remains, we are shutting down a perfectly good facility which is still contributing cutting edge research. Cern might have a more powerful accelerator, but (if you forgive the analogy) having the most powerful telescope imaginable does not grant you enough time to scan the universe at full power. Being the second best does not imply having no value.

Agreed. I did not mean to imply that it's a good idea to shut down the Fermilab collider. E.g. just buying one stealth fighter less could keep that facility running for the next decade.

'implied non em-interactive matter' would be a better term than 'dark matter'

You're welcome to submit that to the relevant people. The term 'dark matter' wasn't coined with its use in pop-sci magazines in mind.

But, alas, such are political prioriies...
El_Nose
not rated yet Aug 25, 2011
the Higg's by 2012 and tests for super symmetry by 2014 --

Once we understand the fundamental laws what else is there ??
Deesky
4.2 / 5 (5) Aug 29, 2011
the Higg's by 2012 and tests for super symmetry by 2014 --

Once we understand the fundamental laws what else is there ??

The precursors to the fundamental laws. :)
antialias_physorg
not rated yet Aug 29, 2011

Once we understand the fundamental laws what else is there ??

The thing is: There are no fundamental laws.

If there were the one could always ask: Where did they come from? What makes them the way they are? Why aren't they different?

The thing about askin after fundamentals is: You always imply a causation principle (of which itself you could ask: why causation?).
Causation also always implies a temporal vector, which itself isn't always a given (especially around the big bang and maybe not with singularities)

So the question of searching for 'fundamentals' may be flawed in itself.
Remember that these laws we search for are only models for observations. And it seems that either we must model in a wholly different (i.e. atemporal) way or just settle for 'good enough' at some point.
rawa1
1 / 5 (1) Aug 29, 2011
So far LHC effectively disproved most of theoretical physics of the last forty years: Higgs, SUSY and WIMPS, Technicolor, extradimensions, leptoquarks, Randall-Sundrum gravitons, micro-black holes, CPT violation for antimatter...
Vendicar_Decarian
1 / 5 (1) Aug 29, 2011
"Maybe if the USA decomissions a couple of stealth bombers, or I dunno .." - SAtargaser

Ok, then the U.S. yearly deficit would be 1,584 billion per year.

Vendicar_Decarian
1 / 5 (1) Aug 29, 2011
"So the question of searching for 'fundamentals' may be flawed in itself. " - Antial..

That would simply imply that standard mathematics does not apply to the real world in a 1:1 manner.
antialias_physorg
4.5 / 5 (2) Aug 29, 2011
That would simply imply that standard mathematics does not apply to the real world in a 1:1 manner.

Yes. I don't think it is a given to assume that a modeling tool (which is what mathematics is) should therefore auto"magically" be able to encompass each and very aspect of the thing it models.

The map is not the territory.

The final problem is: It COULD all be chance. There COULD actually be no forces/laws whatsoever. Getting 1000 times 'heads' on a coin toss means that the probability for a completely random coin is still not zero.
So whatever law we come up with - no matter how perfectly it seems to fit with all future observations - we can never be 100% sure if it actually maps to some underlying principle or whether it's just a fluke.*

* Note that I'm in no way suggeting that we should therefore abandon the search for ever more fundamental laws - quite the opposite. Just that that search is unlikely to ever have an end or lead to a fundamental/unambiguous 'truth'.

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