Apologies for the continued hiatus

Apologies for the continued and still continuing hiatus, readers. I’m talking time off from school/work/research/blogging and have been for some time now, for those who weren’t aware. I have an unfortunate slew of health issues (auto-immune disease) that I’m dealing with right now and have had to step back from some things to keep the work-life balance in check. Hopefully, I’ll be making my return to blogging (and physics [and health]) soon.

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Higgs Gossip: Observation of a γγ resonance at a mass…

Update (April 25th, 2011) at end.

So I woke up this morning to several emails about a strange “Higgs sighting” at ATLAS.  On a Woit’s blog, a commenter named Higgs? shared an abstract purporting observations of some 115 GeV resonance at CERN.  It claims to be from an “internal note” from the ATLAS Collaboration.

Higgs? says:

Internal Note
Report number ATL-COM-PHYS-2011-415
Title Observation of a γγ resonance at a mass in the vicinity of 115 GeV/c2 at ATLAS and its Higgs interpretation
Author(s) Fang, Y (-) ; Flores Castillo, L R (-) ; Wang, H (-) ; Wu, S L (University of Wisconsin-Madison)
Imprint 21 Apr 2011. – mult. p.
Subject category Detectors and Experimental Techniques
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords Diphoton ; Resonance ; EWEAK ; HIGGS ; SUSY ; EXOTICS ; EGAMMA
Abstract Motivated by the result of the Higgs boson candidates at LEP with a mass of about 115~GeV/c2, the observation given in ATLAS note ATL-COM-PHYS-2010-935 (November 18, 2010) and the publication “Production of isolated Higgs particle at the Large Hadron Collider Physics” (Letters B 683 2010 354-357), we studied the γγ invariant mass distribution over the range of 80 to 150 GeV/c2. With 37.5~pb−1 data from 2010 and 26.0~pb−1 from 2011, we observe a γγ resonance around 115~GeV/c2 with a significance of 4σ. The event rate for this resonance is about thirty times larger than the expectation from Higgs to γγ in the standard model. This channel H→γγ is of great importance because the presence of new heavy particles can enhance strongly both the Higgs production cross section and the decay branching ratio. This large enhancement over the standard model rate implies that the present result is the first definitive observation of physics beyond the standard model. Exciting new physics, including new particles, may be expected to be found in the very near future.

See: http://cdsweb.cern.ch/record/1346326?

Is this a Higgs sighting? Well, the abstract says, “the event rate…is about thirty times larger than the expectation from Higgs to γγ in the standard model” making it certainly not evidence for a Standard Model Higgs.  Is it a real observation? That’s a better question at this point.  Better still, is this a real note?

I don’t work with CERN, so my login doesn’t give me permission to access internal memos (in fact, I can only read the partial title “Observation of a γγ resonance at a mass”?) although others have told me that the paper is actually there and does claim what the abstract is presenting (although perhaps not convincingly).

One of my favourite ATLAS postdocs, Mark Tibbetts, said,

The line from the management is “This is not an official result of the ATLAS experiment.”

“Not an official result”. Hmm…

Now, the authors are a little interesting because they include Sau Lau Wu. Wu is often associated with her excitement, near the end of the LEP days, when her team thought they had observed a Higgs candidate around 114GeV/c2 (it was basically ruled out later).  The energies being so similar here make this curious.

Another important thing to point out is that the CDF has also been focused on the H→γγ search and has seen no 115 GeV bump in their data [see Search for a Standard Model Higgs Boson Decaying Into Photons at CDF Using 7.0 fb-1 of Data [pdf] from April 18th, 2011].  If this sizable 115 GeV bump was being found in ATLAS data, the CDF should also have seen a hint of it, not, nothing.

At this point, I see no reason in speculating on what this [result] means.  It’s a rumour.  The analysis may be very limited.  The data may be non-existent.  And it’s not impossible that someone uploaded it to the CERN servers as a joke.  If the ATLAS Collaboration were to release it themselves, then we could be excited (and if people want to start throwing around “fourth generation”, “non-Standard Higgs”, “SUSY confirmed/ruled out”, then it might be reasonable).  Until there is an official statement from the collaboration, or even one of the co-authors, this is just gossip.  Don’t get excited.  Seriously.

For more remarks, analysis, and speculation:

Update: April 25th, 2011: “Spokeswoman quashes Higgs particle rumor” in Nature.

ATLAS’ spokeswoman Fabiola Gianotti stops short of disowning the leaked document, but tells Nature signals of the kind reported in the memo show up quite frequently in the course of data analysis and are later falsified after more detailed scrutiny. “Only official ATLAS results, i.e. results that have undergone all the necessary scientific checks by the Collaboration, should be taken seriously,” she says.

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What’s been going on in the universe

So my readers probably noticed the fact that this blog just stopped mid-February, without any explanation.  Life in our local part of the universe was substantially more chaotic than usual.  World wide protests, devastating natural disasters, nuclear fears, war, and us just trying to go about our day to day lives, buying a home, securing funding, getting sick, planning a wedding, all the while not looking at what was sitting just out of the corner of our eyes.

When the world is in crisis, physics doesn’t stop, science doesn’t stop.  Wars, famine, the need to rebuild – all of these are actually great motivators for researchers.  Unfortunately, most of us aren’t in fields that can actually offer anything close to intellectual assistance during these times.  There is a strange and sad fact about this planet and the animals that inhabit it though, and that is that there is always some part of the world that is in crisis.  If we took a pause every time something unimaginable to us happened, very little would ever get done.  Nevertheless, I paused.

To get back into things, here’s about a months worth of reading – there should be two other posts out later this week (back to some more serious blogging too). Astrophysics and Gravitation gives us some updates on the MOND versus dark matter debate (is MOND winning? or have we already seen dark matter?), a silly paper on stars with wormhole centres, another success for Einstein@Home, a possible explanation for the “Fermi Bubble”, a new value for the Hubble constant, a long overdue fix for the Pioneer Anomaly, and a huge explosion in space for NASA. Lots of news from CERN and Fermilab in High Energy & Particles, including the search for SUSY at the LHC, the hunt for the Higgs, a single top quark at the CMS, heavy antimatter for ALICE, the much hyped results of new physics at the Tevatron, and using a Fermi-Fermi gas to model the Big Bang. Finally in General Relativity & Quantum Gravity we get a lesson on quantum Riemann surfaces in Chern-Simons theory, a curious experiment using gravity waves to suss out dimensionality, an introduction to group field theories, BF models of gravity, and spin foams, an update on the status of Horava gravity, an absurd paper on life inside black holes, and an essay from the 1960s by George Gamow.

Continue reading »

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Apologies for the blogging hiatus

Posts here will re-commence this week.

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This “Week” in the Universe: February 1st – February 21st

So I’ve been remiss in my reading lately, but here are my picks from the past few weeks.  We have Outstanding Problems in Galaxy Formation, Herschel on Dark Matter, Dark Matter Detection Discussed, “Symmetry Breaking” in Graphene?, Closed Timelike Curves and Postselection, Frame-Like Geometry of Double Field Theory, and Loop Lectures with Carlo Rovelli.
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Happy Valentine’s Day

Since I didn’t have the time to put together another Valentine’s Day special, like last year’s “The Mathematician’s Valentine“, you get ‘Colour Your Own Physics Valentine’s Day Cards’ for all occasions:

The romantic doubly-special Valentine:

The platonic BF theory Valentine:

And finally, the awkward and sexual cosmic censorship Valentine:

Happy Valentine’s Day

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This Week in the Universe: January 25th – January 31st

Just a link collection today; I’m scrambling with deadlines right now.

Astrophysics and Gravitation:

New Most Distance Galaxy Candidate Found

For more, see NASA’s Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe.

Bayesian Model to Determine Size of the Universe

M. Vardanyan, R. Trotta, & J. Silk (2011). Applications of Bayesian model averaging to the curvature and size of the Universe arXiv arXiv: 1101.5476v1

For more, see New Model Says the Cosmos Is At Least 250 Times Larger Than the Visible Universe.

Black Hole – Dark Matter Correlation? Nope.

John Kormendy, & Ralf Bender (2011). Supermassive black holes do not correlate with dark matter halos of galaxies Nature 469, 377 (2011) arXiv: 1101.4650v1

For more, see Dark matter does not act as a growth factor.

High Energy Physics and Particles:

Measurement of the Muon Lifetime and Determination of the Fermi Constant

D. M. Webber et al. (MuLan Collaboration) (2011). Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision Physical Review Letters, 106 (4) DOI: 10.1103/PhysRevLett.106.041803

For more, see How Strong Is the Weak Force? New Measurement of the Muon Lifetime.

General Relativity, Quantum Gravity, et al.:

Virtual Black Holes in Hyperbolic Metamaterials

Igor I. Smolyaninov (2011). Virtual Black Holes in Hyperbolic Metamaterials arXiv arXiv: 1101.4625v1

For more, see Physicist Discovers How To Make Quantum Foam In A Test Tube.

Gravity as a Diffeomorphism Invariant Gauge Theory

Kirill Krasnov (2011). Gravity as a diffeomorphism invariant gauge theory arXiv arXiv: 1101.4788v1

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It’s Official: The LHC will run through 2012

From today’s press release:

Geneva, 31 January 2011. CERN today announced that the LHC will run through to the end of 2012 with a short technical stop at the end of 2011. The beam energy for 2011 will be 3.5 TeV. This decision, taken by CERN management following the annual planning workshop held in Chamonix last week and a report delivered today by the laboratory’s machine advisory committee, gives the LHC’s experiments a good chance of finding new physics in the next two years, before the LHC goes into a long shutdown to prepare for higher energy running starting 2014.

The LHC was previously scheduled to run to the end 2011 before going into a long technical stop necessary to prepare it for running at its full design energy of 7 TeV per beam. However, the machine’s excellent performance in its first full year of operation forced a rethink. Expected performance improvements in 2011 should increase the rate that the experiments can collect data by at least a factor of three compared to 2010. That would lead to enough data being collected this year to bring tantalising hints of new physics, if there is new physics currently within reach of the LHC operating at its current energy. However, to turn those hints into a discovery would require more data than can be delivered in one year, hence the decision to postpone the long shutdown. If there is no new physics in the energy range currently being explored by the LHC, running through 2012 will give the LHC experiments the data needed to fully explore this energy range before moving up to higher energy.

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This Week in the Universe: January 18th – January 24th

Phenomenally beautiful math was the main highlight of this week, I’d say, although none of it for the very faint of heart.

The CMS on SUSY, Bill Unruh on simulated Hawking radiation, Ed Witten on knots, and Schenkel and Van Oystaeyen on noncommutative space(times):

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Finite formula found for partition numbers

Credit: Emory and Ken Ono

So this isn’t physics*, but if you squint hard enough, you can probably make a connection.  The hot topic today is Ken Ono‘s latest work on the partition function:

Ken Ono, Amanda Folsom, & Zach Kent (2011). l-adic properties of the partition function American Institute of Mathematics.

Ken Ono & Jan Bruinier (2011). AN ALGEBRAIC FORMULA FOR THE PARTITION FUNCTION American Institute of Mathematics.

A EurekAlert press release appeared today, entitled: New math theories reveal the nature of numbers and people are already whispering “Fields Medal”. Now, I haven’t thoroughly read the paper yet, but, since I’m not a number theorist, my commentary probably won’t change very much anyway.  Obviously, like most press releases, this one is full of hyperbole and ridiculous sentences like, “the team was determined go beyond mere theories”, but the actual work being discussed is fascinating.
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