Large Hadron Collider (LHC) News

[Jens]

Wow - does this mean lots of BAUT members only check BAUT when they are at work? Hmmm

Probably more that on July 4, there are lot of things like fireworks and town fairs in the US, so people will not be at home. I would assume that people check on Saturdays and Sundays at home.

[tnjrp]

In regards to the numerous "what now" questions, doctor Dave Goldberg fervently hopes this latest announcement has at least one practical application:
http://io9.com/5923170/stop-calling-it-the-god-particle

[Van Rijn]

Probably more that on July 4, there are lot of things like fireworks and town fairs in the US

And picnics, house parties, block parties . . . lots of things.

[Xelebes]

In regards to the numerous "what now" questions, doctor Dave Goldberg fervently hopes this latest announcement has at least one practical application:
http://io9.com/5923170/stop-calling-it-the-god-particle

Let's call it Weighty.

[Ara Pacis]

In regards to the numerous "what now" questions, doctor Dave Goldberg fervently hopes this latest announcement has at least one practical application:
http://io9.com/5923170/stop-calling-it-the-god-particle

I can agree with that.

This is why government, philanthropists or business should fund pure science. Marketing and appealing to pop-culture seems to never end well for physicists.

[tnjrp]

If somebody's still confused about that sigma 5, don't be:
http://physicsbuzz.physicscentral.co...discovery.html

[DancesWithFruitBats]

I have heard that the Higgs boson imparts inertial mass rather than gravitational mass. Does anyone understand the difference? Also, how does the Higgs Boson affect either and what is its relation to the graviton?

[Extravoice]

If somebody's still confused about that sigma 5, don't be:
http://physicsbuzz.physicscentral.co...discovery.html

Thanks. That was a nice primer on the bell curve.

[Ivan Viehoff]

I have heard that the Higgs boson imparts inertial mass rather than gravitational mass. Does anyone understand the difference? Also, how does the Higgs Boson affect either and what is its relation to the graviton?

Inertial mass is the m in the equation F = ma (Newtonian approximation). Gravitational mass is the m and M in the equation F = GmM/r^2 (Newtonian approximation).

We are not aware of any inherent reason why a massive object's resistance to motion under application of a force (of any variety), ie its inertial mass, should be the exactly proportional to the force on it due to gravity, implying its gravitational "mass" is the same. So whatever it is that (so far as we can tell) makes the inertial and gravitational masses the same, we do not know.

Since the Higgs mechanism is nothing to do, so far as we know, with gravity, it makes sense to say that the Higgs mechanism determines the inertial mass rather than the gravitational mass. But since they are the same, so far as we can tell, in practice it would appear to determine both.

Gravitons, if they exist, and the Higgs particle are both bosons. That is about as much as we can say about their similarity at the moment. People have been doing plenty of work on gravity on the assumption that the Higgs boson exists, so proving it does exist doesn't take us much further in the investigation of gravity. Maybe some detailed investigation of the Higgs boson's properties will tell us something we don't know.

[lpetrich]

The Higgs particle makes rest masses for most of the other Standard-Model particles. It has nothing to do with inertial vs. gravitational mass.

It makes them massive by interacting with them while always being present, as it were. Without the Higgs particle, all the other Standard-Model particles would be massless. With the Higgs partlcle, only two of them are massless, and that's because of their zero interaction with the Higgs particle: the photon and the gluon.

[trinitree88]

The Higgs particle makes rest masses for most of the other Standard-Model particles. It has nothing to do with inertial vs. gravitational mass.

It makes them massive by interacting with them while always being present, as it were. Without the Higgs particle, all the other Standard-Model particles would be massless. With the Higgs partlcle, only two of them are massless, and that's because of their zero interaction with the Higgs particle: the photon and the gluon.

Ipetrich. Actually there are three masses. The third is the mass that reacts with the ubiquitous neutrino sea, via the three branches of the weak currents, the W⁺, the W^-, and the Z⁰. The last one, the Z⁰, can be any particle/antiparticle pair, and at energies less than 1.022 Gev/c², can only be either a massless photon/anti-photon or a neutrino/antineutrino pair. The latter is Gamow's defined graviton from his text "Gravity"...a Project Physics Reader from the sixties.
I used it years ago to define a trinity of equivalence, and patched it into H.Georgi's SU[5] symmetry (Sci Am. 1981) to make a simple GUT. It successfully predicted the coincidences seen at the Rome/Maryland gravitational wave detectors and the IMB, Baksan, Mont Blanc, and Kamiokande neutrino detectors @ sigma 3.2 during SN1987a and reported @ Neutrino 88 @ Tufts University by Guido Pizella (published in Il Nuovo Cimento C).
It is not a surprise that a resonance is seen @ ~ 125.99 Gev/c², as two energetic Z's....one a W⁺/W^- pair can interract with a second Z that is splitting such that the final transient state has a mass of ~125.99 as was first noted by Lubos Motl on his blog.

pete


SEE:http://cupp.oulu.fi/neutrino/nd-cross.html

SEE:http://motls.blogspot.com/2012/07/hi...n-100.html?m=1

SEE:http://en.wikipedia.org/wiki/Lubo%C5%A1_Motl

[lpetrich]

Ipetrich. Actually there are three masses. The third is the mass that reacts with the ubiquitous neutrino sea, via the three branches of the weak currents, the W⁺, the W^-, and the Z⁰. The last one, the Z⁰, can be any particle/antiparticle pair, and at energies less than 1.022 Gev/c², can only be either a massless photon/anti-photon or a neutrino/antineutrino pair. The latter is Gamow's defined graviton from his text "Gravity"...a Project Physics Reader from the sixties.

That seems to me totally mixed up. I'd recommend Wikipedia as a source, except that it's rather confused. So I'm using this instead:


CERN mug summarizes Standard Model, but is off by a factor of 2

Here is what each term means:

• Gauge-particle kinetic energy and self-interaction.
• Elementary-fermion kinetic energy and gauge-particle interaction.
• "Hermitian conjugate", a sort of mirror image. This one is redundant, and makes the aforementioned factor-of-2 error.
• Elementary-fermion-Higgs-particle interactions.
• "Hermitian conjugate" again, but a necessary one this time.
• Higgs-particle kinetic energy and gauge-particle interaction.
• Higgs-particle potential energy.

All the "particles" here are quantized fields.

D = gradient with gauge-particle interaction
psi = elementary fermion
phi = Higgs particle
y's = interaction strengths
V = potential

The ultimate origin of Standard-Model-particle mass is the Higgs potential term. It makes the lowest-energy value of phi nonzero, and its continual presence then gives masses to the elementary fermions and some of the gauge particles.

[Extravoice]

The BBC is reporting that the Atlas team is claiming 5.9 sigma:

link

The article says they are sure they found a particle, but still have to confirm that it is the particle they were expecting.

[Ara Pacis]

The BBC is reporting that the Atlas team is claiming 5.9 sigma:

link

The article says they are sure they found a particle, but still have to confirm that it is the particle they were expecting.

So, if it's not the boson, then it must be closely related right... Some sort of Boson's Mate? ;-)

[Extravoice]

So, if it's not the boson, then it must be closely related right... Some sort of Boson's Mate? ;-)

I didn't know that the CQ rules allowed for such leeward jokes.

[Noclevername]

You guys better keep it on an even keel.

[Ara Pacis]

Why are you guys always trying to take the wind out of my sails?

[Noclevername]

Q: What do you do with a subatomic pirate?

A: Make him walk the Planck.

[trinitree88]

Q: What do you do with a subatomic pirate?

A: Make him walk the Planck.

Noclevername. oHHHHH!....Even worse, make him walk the Planck on a building's ledge, subatomic pirates are afraid of Widths, not Heights

[trinitree88]

That seems to me totally mixed up. I'd recommend Wikipedia as a source, except that it's rather confused. So I'm using this instead:


CERN mug summarizes Standard Model, but is off by a factor of 2

Here is what each term means:

• Gauge-particle kinetic energy and self-interaction.
• Elementary-fermion kinetic energy and gauge-particle interaction.
• "Hermitian conjugate", a sort of mirror image. This one is redundant, and makes the aforementioned factor-of-2 error.
• Elementary-fermion-Higgs-particle interactions.
• "Hermitian conjugate" again, but a necessary one this time.
• Higgs-particle kinetic energy and gauge-particle interaction.
• Higgs-particle potential energy.

All the "particles" here are quantized fields.

D = gradient with gauge-particle interaction
psi = elementary fermion
phi = Higgs particle
y's = interaction strengths
V = potential

The ultimate origin of Standard-Model-particle mass is the Higgs potential term. It makes the lowest-energy value of phi nonzero, and its continual presence then gives masses to the elementary fermions and some of the gauge particles.

Ipetrich. Yep, the other side of the mug has the equations from the blackboard in the background that tries to explain the mystery that is.............a woman. :rollseyes-default: pete

[lpetrich]

[1207.7214] Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
[1207.7235] Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

ATLAS
Mass = 126.0 +- 0.4 (stat) +- 0.4 (syst) GeV
CMS
Mass = 125.3 +- 0.4 (stat) +- 0.5 (syst) GeV

Higgs decay | Stdevs | - | Obs/SM | -
2-photon | 3.4, 3.2, 4.5 | 4.1 | 1.8 +- 0.5 | 1.6 +- 0.4
Z(Z) -> 4l | 2.5, 2.6, 3.6 | 3.2 | 1.4 +- 0.6 | 0.7 +- 0.35
W(W) -> lnln | 1.3, 3.3, 2.8 | 1.7 | 1.3 +- 0.5 | 0.7
Total | 3.6, 4.9, 6.0 | 5.0 | 1.4 +- 0.3 | 0.87 +- 0.23
Stdevs: for 7 TeV, 8 TeV, both (ATLAS), both (CMS)
Obs/SM: ATLAS, CMS

l = charged lepton
n = neutrino
Z(Z), W(W) - one Z or W virtual

Tau-tau and bottom-bottom decays not observed with good statistical significance at either ATLAS or CMS.

The decay rates are consistent with the Standard Model, though the margins of error are large, and though the photon-photon decay is a bit fast.


Global number of stdevs (look-elsewhere effect)
Detector | Range (GeV) | Stdevs
ATLAS | 110 - 150 | 5.3
ATLAS | 110 - 600 | 5.1
CMS | 115 - 130 | 4.6
CMS | 110 - 145 | 4.5
Range = range of possible Higgs-particle masses

[ShinAce]

We had a public lecture at Carleton university on the Higgs Boson. The second speaker was Thomas Koffas and he seemed to be intimately involved with the ATLAS detector.

At any rate, I had a chance to ask him when we might get confirmation of isotropic decay of the Higgs. He basically said there's currently little to no data on that, and it should be forthcoming by the end of this year. Which is to say probably in 2014 after the upgrade.

[Jens]

The second speaker was Thomas Koffas and he seemed to be intimately involved with the ATLAS detector.

I hope not too intimately, though. It often ends up badly when scientists become romantically involved with their instruments.

[Jerry]

Which gender do the French assign to a detector?

[nota]

Ipetrich. Actually there are three masses. The third is the mass that reacts with the ubiquitous neutrino sea, via the three branches of the weak currents, the W⁺, the W^-, and the Z⁰. The last one, the Z⁰, can be any particle/antiparticle pair, and at energies less than 1.022 Gev/c², can only be either a massless photon/anti-photon or a neutrino/antineutrino pair.

pete

what is an anti-photon ??

a bit of dark ??

[lpetrich]

There isn't a separate antiphoton -- the photon is its own antiparticle, just like the Z and the Standard-Model Higgs particle.