What Exactly Was That "Ghost Particle" And How Was It Detected?

Artist's conception of the blazar in Orion  that emitted the ghost particle (aka neutrino) detected at the Ice Cube facility in Antarctica.

As usual, the media in stories about this "revolutionary" astrophysical find, chooses terms like "ghost particle" aiming to elicit plenty of clicks.  In fact, the term can apply to any neutrino precisely because one of the properties of these near massless particles is the ability to pass through an enormous amount of matter without causing any reaction. Like the cartoon character "Caspar the friendly ghost",  they can literally pass through walls. In fact, only about 1 in ten billion neutrinos traversing a matter barrier equal to Earth's diameter, reacts with even a proton or neutron.

Hence, by virtue of being unaffected by normal matter, radiation or gravity we have "ghostly neutrinos". 

In the case of the recent discovery-  announced Thursday at the National Science Foundation- we learned one and only one neutrino "made the cut"  in being detected by Ice Cube. This neutrino arrived from a "blazar" - a hyper active galaxy in the constellation Orion, 3.7 billion light years distant - and hurling neutrinos like particles from a cosmic ray gun.  Indeed, the international team assembled in D.C. for the announcement believes the neutrino- spewing blazar to be the first known source of higher energy cosmic rays to reach Earth.  See also:

http://brane-space.blogspot.com/2012/10/unlocking-secrets-of-galactic-cosmic.html

This particular neutrino intercepted the Ice Cube detector in September, 2017, with an energy of 290 terra electron volts. (Recall here that 1 eV = 1.6 x 10 ^-19 J) . That energy is some 40 times greater than similar particles produced in the Large Hadron collider.   But how do we know, what signature do we have, that it was a neutrino?  Also what type of neutrino?  Recall I had discussed three different types in an earlier post, the electron neutrino, tau neutrino and muon neutrino, e.g.

http://brane-space.blogspot.com/2016/11/whither-all-the-missing-neutrinos.html

In the current single neutrino case from the blazar, it appears we have a muon neutrino - based also on archival data. We suspect it is an actual neutrino because the little bugger generated Cherenkov radiation, and hence able to move faster than the speed of light c, in ice.   Some accounts have the muons moving faster than light, period, which is incorrect. It is faster than light in the ice, e.g. forming the Ice Cube detector.   Moving faster than light through a medium like ice, the muons, electrons spun off, glow or flare.   It is the sensors in the ice of the Ice Cube that "spotted" the flares and from that - and some useful statistical analysis (see bottom of post) the neutrino interaction was deduced.   The initial discovery was confirmed by astronomers at 20 different observatories. The find itself caps almost 20 years of work by a collaboration comprising 300 astrophysicists and astronomers (you can more easily see their names appended to the pdf version  of one of the papers accessible at the end.)

OK, so how did the above reference "confirmation" take place? Well, lo and behold, at nearly the same time , the Fermi Gamma-ray Space Telescope   detected an increase in energetic activity from the same direction as the blazar. Coincidence? Nope, the contributing researchers don't buy it, mainly because the rigorous statistics indicates a physical connection. Readers can read the end conclusion in the paper for yourselves. (Of course, the uncertainty is measured in so many standard deviations and these measurements aren't entirely free of them so the participating team members can't be 100 percent sure, but they're maybe at least 70-80 percent sure. Which is a pretty good marker in astrophysical research!

Some 8 years ago, I wrote at the end of a post ('Neutrinos Then And Now',  Oct. 26, 2010  about the planned construction of the "Ice Cube" neutrino detector in Antarctica. I wrote at the time:

"Many other physicists and astronomers are interested in detecting neutrinos from much more distant objects, such as supernovas, and colliding galaxies. To that end, an enormous neutrino telescope detector called "Ice Cube" is being constructed inside an ice field in Antarctica. (See attached image). Its sensors will be aimed not only at the sky but toward the ground to detect neutrinos from the Sun and outer space that are coming through the planet"

The image shown at the time was extremely crude with virtually no details, but the one I show below basically indicates the most critical aspects.


The Ice Cube detector:


The Observatory seen in macro-frame:

Key aspects:

-In-Ice Sensor Network.   Engineers used hot water to melt 86 different holes a mile deep or more into the ice. There they lowered also 5,160 electric-optical sensors  then allowed them to freeze in place.

- Deep core:  The sensors are able to detect the flare (glow) from a rare neutrino- normal atom collision as the neutrino speeds through the array. The signal is then relayed to the surface, accurate to within 5 billionths of a second.

-The sensors start at a depth of 4,593 feet.


- When the neutrino collides with a proton or neuron a particle called a muon emerges. It radiates blue light as it moves through the ice along the same path as the neutrino.

 The full paper of the discovery referencing one aspect (using an analysis based on self-correlation of multiple neutrinos, prior to the specific Ice Cube Alert)  for those interested may be found here:
http://science.sciencemag.org/content/361/6398/147.full

 The key conclusion to note is:

The analysis of the Ice Cube-170922A event in (20) relies on correlation of a single neutrino with electromagnetic activity, whereas the analysis presented here relies only on self-correlation of multiple neutrinos. The coincidence of an Ice Cube alert with a flaring blazar, combined with a neutrino flare from the same object in archival Ice Cube data, pinpoints a likely source of high-energy cosmic rays.

The other paper referencing the single neutrino capture based on the simultaneous Fermi gamma ray Space telescope detection - prompting the Ice Cube alert-  can be found here:

http://science.sciencemag.org/content/361/6398/eaat1378.full

Of  course, there are always going to be pseudo conspiracy wackos who try to skew scientific or astrophysical finds into spurious conspiracy ideations, like this:

https://www.youtube.com/watch?v=4x_wNM86kRk
-------------------------------
Addendum:

Let's review again these neutrino flavors for good measure. If there are three flavors: electron, muon and tau, then there must be three different corresponding neutrino masses which we can call: m1, m2 and m3.Further, the three "flavors" are really different superpositions of the 3 basic neutrino mass states.  Moreover, and to make it more complex, we know that quantum interference between mass states means a neutrino originating in one "flavor" can transmogrify to another over its transit.

Because of the oscillations and quantum interference we need to reckon in a "misalignment" between flavor and the basic neutrino masses. This is done by reference to three independent "mixing angles": Θ_12 , Θ_23  and Θ_13. To a good approximation, oscillation in any one regime is characterized by just one Θ_ij and a corresponding mass difference, defined:

 D m _ij² = [m _j² - m _i²]

As an example, the probability that a muon neutrino of energy E acquires a different flavor after traversing distance L is:
P = sin² Θ ₂₃  sin² (l₂₃)
 
where l23 is the energy -dependent oscillation length, given by:
4ħ E c /  (D m ₃₂²)
How well do we know the parameters? Atmospheric neutrino observations yield:
 Θ ₂₃  ~ 45 degrees, while D m ₃₂² = 0.0024 eV². Meanwhile, solar neutrino data yield roughly 33 degrees for Θ₁₂ and  D m ₂₁² = 0.00008 eV². (Note: ħ is the Planck constant of action divided by 2 π)  If then:
D m ₃₁²  =  [D m ₂₁²    +  D m ₃₂² ] = 0.00008 eV² + 0.0024 eV²
We know, D m ₃₁²  =  0.00248
which is close to D m ₃₂²

'God Particle' Theorists Get Nobel Prize in Physics - But Pieces of Higgs Puzzle May Still Be Missing

The announcement yesterday of the award of the Nobel Prize in Physics created quite a media storm. Half a century after he formulated the theory that would change the world, Peter Higgs,  84, of Edinborough University, shared the 8 million Swedish kronor (£775,000) prize with François Englert at the Free University of Brussels.

The pair received the prize for showing how fundamental particles get their masses. Before the theory, the answer to this basic question was unknown After all, they had postulated the existence of the "God Particle" - otherwise known as the Higgs boson. It can be thought as the "glue" which holds particles of mass together.


In the parlance of The Royal Swedish Academy, the prize was awarded  for "the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the Atlas and CMS experiments at Cern's Large Hadron Collider."

What is the background here? It basically began when the two theorists produced a series of papers in 1964 that described how an invisible field that lurks in the vacuum of space interacts with elementary particles and gives some of them mass.  Now, this was still before Arno Penzias and  Robert Wilson's detection of the 2.7 K isotropic radiation subsequently traced to the "Big Bang". And hence, before the cohering process that resulted in what's been called the Standard Model.

Elaborating a bit: this so-called 'Standard Model' is generally defined as the symmetry:

SU(3) x SU(2) X U(1)

where each of the above denotes a specific matrix, or more exactly a group. See, e.g.

http://brane-space.blogspot.com/2010/04/looking-at-groups.html

In the case of SU(2) we describe it as the "special unitary group" which has the form:

S =

(a.........-b*)
(b..........a*)

where a*, b* are complex conjugates and we have (aa* + b*b) = 1. Thus the elements of SU(2) are the unitary 2 x 2 matrices with DET (determinant) = 1. These groups thus define the behavior of a specific class of subatomic particles. Spontaneous symmetry breaking would therefore resolve this combination into constituent parts, e.g.: SU(3) associated with the 'color force' of quarks:

 SU(2) x U(1)

associated with the electro-weak force.

One possible symmetry breaking (quark -boson format) is:

SU(3) x SU(2) X U(1) -> SU(3) + SU(2) x U(1)

which would occur at a particular ambient temperature (T_qb) for the universe at some epoch (E_qb) in the past. In the foregoing, the synthesis of SU(2) and U(1) into the locally gauge invariant electro-weak theory requires a mechanism which confers mass to three vector bosons while leaving the photon massless. This 'mass-giving' mechanism is called the Higgs Field or Higgs mechanism, and it demands the existence of one or more massive, spin-0 bosons otherwise called Higgs bosons.

Last year, theory evidently transmuted into reality when the discovery (thanks to the large hadron collider)  was announced at CERN. As I noted (in a July 4 blog post), Dr. Rolf Heuer, director general of CERN, while referring to the new discovery as "a historic milestone"  nevertheless cautioned that it was too soon to know for sure if the new particle (coming in at 125 billion electron volts) is actually the long sought particle. (Also, was it a unique Higgs, or just one of several?)

The problem? The culmination of analyses of over 800 trillion proton-proton collisions over the 2 years leading up to the announcement generated a quandary. When buttonholed,  the physicists admitted they  actually knew little. The CERN results were mostly based on measurements of two or three of the dozen different ways, or “channels,” by which a Higgs boson could be produced and then decay. Worse, there were hints that some of the channels were overproducing the Higgs while others might have been underproducing. In either case, false positives or false negatives, one had to look askance at the initial results.

The upshot? There may not have been a real Higgs discovered but a spurious 'mirage' imitating some of its properties but more a confection of the data than based in reality. Also, assuming a genuine signal or find, it may not have been unique but only ONE of two or three different Higgs bosons. Much like the case of the neutrino, which was once believed to be one entity only, but we now know is THREE: the electron neutrino, the tau neutrino and the muon neutrino, see e.g. http://brane-space.blogspot.com/2012/06/solving-neutrino-puzzleand-matter.html


By March 15 of this year the issue appeared settled, to the extent that at least that ONE Higgs had indeed been  found,  when CERN's brain trust stopped dithering and announced that the particle described in July 2012 was, in fact, a Higgs Boson. Spokesman Joe Incandela said in a statement issued March 15 :

“The preliminary results with the full 2012 data set are magnificent and to me it is clear that we are dealing with a Higgs boson though we still have a long way to go to know what kind of Higgs boson it is,”

 To make this final determination, the dataset was analyzed to see if the quantum properties of the boson discovered in July matched the properties that are currently predicted by physics. After tests in two different detectors, it was confirmed that the particle possessed those properties

Ben Allanach, a theoretical physicist at Cambridge University, said:

"This is the recognition of a triumph for fundamental physics that will stay in the history books for millennia to come. I am thrilled about the prize, and Englert and Higgs both deserve it well. I cannot over-stress the importance of the discovery. The mass mechanism that the Higgs boson is a signal for has had a huge impact on particle physics over the last 50 years. I think many of us felt that it had to be correct, although we were willing to let data dissuade us."

Maybe. But it would still be nice to finally also settle the issue of whether the putative discovery is unique, or if other Higgs bosons may be lurking in the vacuum. To that end further experiments using an upgraded Large Hadron Collider may be called for. Unfortunately,  the LHC is  currently closed down for repairs. But the team is working on making it faster and more powerful. By then, the final questions may be settled at last and we can then know the extent to which the Standard Model needs to be revised.

Let's Not Jump the Gun with the Higgs!

CERN physicists in a webcast tried to share their excitement with colleagues around the world, on their putative discovery of the Higgs. Well, can you blame them for being somewhat impatient? We're talking about a search lasting decades that's likely been one of the costliest in the history of science. We're talking of a location with its Large Hadron Collider, that was set up as THE place to dig out the Higgs boson - especially after the Superconducting Supercollider in the U.S. fell through due to lack of funding. One of the sorriest retrenchments in our history, followed by the retreat from space (and please don't get me going on the so-called "private sector" space exploits!)

Anyway, Dr. Rolf Heuer, director general of CERN, while referring to the new discovery as "a historic milestone" was nevertheless cautious in asserting that it's too soon to know for sure if the new particle (coming in at 125 billion electron volts) is actually the long sought particle. I totally agree and would suggest hypers, humpers and pumpers pipe down until further analyses are made. To be blunt, it's way too soon to be saying definitiely that THE Higgs has been found. (People may still recall how too many jumped the gun last year on the discovery of "superluminal neutrinos")

To fix ideas here, the subatomic particles are basically classified into two groups according to their "spin" - see e.g.

http://brane-space.blogspot.com/2010/07/more-quantum-mechanics-electron-spin.html

as either FERMIONS (example: the electron) or BOSONS. The Fermions are called so because they obey Fermi- Dirac statistics, e.g. http://en.wikipedia.org/wiki/Fermi%E2%80%93Dirac_statistics

while the BOSONS (for example the photon, and Higgs boson) obey Bose-Einstein statistics: E.g.  http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_statistics

Thus, these "statistics" are critical in basically determining, or rather predicting, the extent of occupancy of the particular species of particle with reference to the energy state of the particle.

The existence of the Higgs itself is tied to the so-called "Standard Model", according to which the Higgs is the only visible (and accessible) manifestation of an invisible field called the "Higgs field".   The so-called 'Standard Model' is generally defined as the symmetry: SU(3) x SU(2) X U(1)

where each of the factors defines a matrix. (Readers can review any of the past blogs on matrices, including unitary or posed as groups. See, e.g. http://brane-space.blogspot.com/2010/05/looking-at-matrix-groups.html. )Spontaneous symmetry breaking would therefore resolve this combination into constituent parts, e.g.:

SU(3) associated with the 'color force' of quarks

SU(2) x U(1) associated with the electro-weak force

One possible symmetry breaking (quark -boson format) is:

SU(3) x SU(2) X U(1) -> SU(3) + SU(2) x U(1)

which would occur at a particular ambient temperature (T_qb) for the universe at some epoch (E_qb) in the past. In the foregoing, the synthesis of SU(2) and U(1) into the locally gauge invariant electro-weak theory requires a mechanism which confers mass to three vector bosons while leaving the photon massless. This 'mass-giving' mechanism is called the Higgs Field or Higgs mechanism. It demands the existence of one or more massive, spin-0 bosons otherwise called Higgs bosons.

The problem? The culmination of analyses of over 800 trillion proton-proton collisions over the past 2 years have generated a quandary. When the physicists are buttonholed they admit they know little. The CERN results are mostly based on measurements of two or three of the dozen different ways, or “channels,” by which a Higgs boson could be produced and then decay. Worse, there are hints that some of the channels are overproducing the Higgs while others might be underproducing.

The upshot? There may not be ONE Higgs here, but two or three. Much like the case of the neutrino, which was once believed to be one entity only, but we now know is THREE: the electron neutrino, the tau neutrino and the muon neutrino, see e.g. http://brane-space.blogspot.com/2012/06/solving-neutrino-puzzleand-matter.html

All we can say now is stay tuned!