Higgs rumors were correct

The official results are in, at least for the LHC's 2011 data, and it appears the rumors were quite accurate. See TRF and QDS for further details. To quote CMS member Dorigo, who stated there is now "Firm Evidence" with the current data,

So the summary is that ATLAS has a 3.6-sigma significance at 126 GeV, by combining their three most sensitive channels; CMS has a 2.4-sigma significance at 124 GeV, by combining all the meaningful search channels -even less sensitive ones.

After an ATLAS and CMS combined plot is produced, there might very well be over 4 sigma evidence for a light Higgs. I'm certain Philip Gibbs is working on a combined plot at this very moment. There is still a Christmas present to be delivered! Stay tuned.

Why a light Higgs is cool

As to why many theorists are excited over news of a possible light Higgs boson with 125 GeV mass, here's a memorable excerpt from a September 2011 interview with Clerk Maxwell Professor of Theoretical Physics and former CERN staff member John Ellis:

In the first scenario (114-135 GeV), we could be looking at a Standard Model Higgs boson. This range has been refined experimentally: recent LHC results presented in Mumbai excluded the Standard Model Higgs from about 135 GeV to about 500 GeV, while LEP had previously excluded it up to 114GeV. That leaves a narrow low-mass range of about 20 GeV where it could lie. But if found in this range, the Standard Model theory would still be incomplete; the present electroweak vacuum would be unstable for such a light Higgs in the Standard Model, so we would have to come up with new physics to stabilise it.

Higgs Candidate Events

While there has been no official announcement on the possible Higgs mass from CERN, there are some nice images available on possible candidate events where the Higgs might have appeared, as mentioned at TRF.

Candidate events in the CMS Standard Model Higgs Search using 2010 and 2011 data (Click images to enlarge)

A typical candidate event including two high-energy photons whose energy (depicted by red towers) is measured in the CMS electromagnetic calorimeter. The yellow lines are the measured tracks of other particles produced in the collision.

A typical candidate event including two high-energy photons whose energy (depicted by red towers) is measured in the CMS electromagnetic calorimeter. The yellow lines are the measured tracks of other particles produced in the collision. The pale blue volume shows the CMS crystal calorimeter barrel.

Real CMS proton-proton collision events in which 4 high energy electrons (green lines and red towers) are observed. The event shows characteristics expected from the decay of a Higgs boson but is also consistent with background Standard Model physics processes.

Real CMS proton-proton collision events in which 4 high energy electrons (green lines and red towers) are observed. The event shows characteristics expected from the decay of a Higgs boson but is also consistent with background Standard Model physics processes.

Real CMS proton-proton collision events in which 4 high energy muons (red lines) are observed. The event shows characteristics expected from the decay of a Higgs boson but is also consistent with background Standard Model physics processes.

All images and descriptions copyrighted property of © 2011 CERN and used for educational purposes.

Higgs rumors at 124.6 GeV

December 13 comes ever closer and the rumors about the Higgs mass get more detailed. Lubos Motl has commented on a recent post at QDS by Tommaso Dorigo in which he seems to hint at a possible Higgs mass from diphoton Higgs decay channels

- gamma: a gamma-ray is a photon, i.e. a quantum of light. A very energetic one, to be sure: a gamma ray is such only if it carries significantly more energy than a x-ray, so above a Mega-electron-Volt or so. The gammas we will be hearing about are those directly coming from a Higgs boson decay, and these have an energy of 62.3 GeV, equivalent to the kinetic energy of a mosquito traveling at 9 centimeters per second.

Here, the Higgs mass 124.6 GeV = 62.3 GeV x 2, from a process that can be written as H -> gamma gamma - where the Higgs decays to two high energy photons. Of course, Tommaso admits

I teased my most gullible readers with a (wrong) covert give-away of the Higgs mass ...

Either way, it is fun to speculate when the actual announcement is only a few days away. So let's see how close this 124.6 GeV is to the official (statistical) CMS value on Monday.

Higgs rumors at 125 GeV

As we all await CERN's official CMS and ATLAS results for the 2011 Higgs hunt, rumors about its mass have surfaced at notable blogs such as Philip Gibbs' viXra log, Peter Woit's Not Even Wrong and Tommaso Dorigo's Quantum Diaries Survivor. As mentioned by "Alex" in the viXra comment section,

Today rumour is: Higgs at 125 Gev around 2-3 sigma…

Such a rumor, if true, would not only indicate evidence for the existence of the Higgs boson, but is evidence for a light Higgs boson (115-135 GeV), which popular models such as E6 GUTs and M-theory on G2-manifolds predict. Of course, 2-3 sigma evidence isn't really conclusive but it does favor physics beyond the Standard Model. These are exciting times and by December 12 and 13 we'll all get to see if the rumors are true. Moreover, Philip Gibbs has also promised everyone a combined CMS and ATLAS plot once the data is released. How's that for an early Christmas present?

Update: Over at Lubos Motl's TRF blog, a commenter "azerty13" said he received the following email from CERN Director General Rolf Heuer:

Dear colleagues,

I would like to invite you to a seminar in the main auditorium on 13 December at 14:00, at which the ATLAS and CMS experiments will present the status of their searches for the Standard Model Higgs boson. These results will be based on the analysis of considerably more data than those presented at the Summer conferences, sufficient to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the Higgs. The seminar will also be webcast.

Rolf Heuer

Such an email, if genuine, definitely supports the 2-3 sigma portion of the 125 GeV Higgs mass rumor. Stay tuned.

Update: As mentioned at viXra log, the latest incarnation of the rumor at Woit's blog gives 3.5 sigma in ATLAS and 2.5 sigma in CMS which amounts to about 4.3 sigma combined for the 10/fb. Keep in mind 5 sigma evidence is what is required at this stage of the Higgs hunting game.

LHC Beams Collide at 7 TeV

Today in Geneva Switzerland beams collided at 7 TeV in the LHC at 13:06 CEST, marking the start of the LHC research programme. Particle physicists around the world are looking forward to a potentially rich harvest of new physics as the LHC begins its first long run at an energy three and a half times higher than previously achieved at any particle accelerator.

“It’s a great day to be a particle physicist,” said CERN Director General Rolf Heuer. “A lot of people have waited a long time for this moment, but their patience and dedication is starting to pay dividends.”

“With these record-shattering collision energies, the LHC experiments are propelled into a vast region to explore, and the hunt begins for dark matter, new forces, new dimensions and the Higgs boson,” said ATLAS collaboration spokesperson, Fabiola Gianotti. “The fact that the experiments have published papers already on the basis of last year’s data bodes very well for this first physics run.”

“We’ve all been impressed with the way the LHC has performed so far,” said Guido Tonelli, spokesperson of the CMS experiment, “and it’s particularly gratifying to see how well our particle detectors are working while our physics teams worldwide are already analysing data. We’ll address soon some of the major puzzles of modern physics like the origin of mass, the grand unification of forces and the presence of abundant dark matter in the universe. I expect very exciting times in front of us.”

"This is the moment we have been waiting and preparing for", said ALICE spokesperson Jürgen Schukraft. "We're very much looking forward to the results from proton collisions, and later this year from lead-ion collisions, to give us new insights into the nature of the strong interaction and the evolution of matter in the early Universe."

“LHCb is ready for physics,” said the experiment’s spokesperson Andrei Golutvin, “we have a great research programme ahead of us exploring the nature of matter-antimatter asymmetry more profoundly than has ever been done before.”

CERN will run the LHC for 18-24 months with the objective of delivering enough data to the experiments to make significant advances across a wide range of physics channels. As soon as they have "re-discovered" the known Standard Model particles, a necessary precursor to looking for new physics, the LHC experiments will start the systematic search for the Higgs boson. With the amount of data expected, called one inverse femtobarn by physicists, the combined analysis of ATLAS and CMS will be able to explore a wide mass range, and there’s even a chance of discovery if the Higgs has a mass near 160 GeV. If it’s much lighter or very heavy, it will be harder to find in this first LHC run.

For supersymmetry, ATLAS and CMS will each have enough data to double today’s sensitivity to certain new discoveries. Experiments today are sensitive to some supersymmetric particles with masses up to 400 GeV. An inverse femtobarn at the LHC pushes the discovery range up to 800 GeV.

“The LHC has a real chance over the next two years of discovering supersymmetric particles,” explained Heuer, “and possibly giving insights into the composition of about a quarter of the Universe.”

Read More @ CERN Press