A real breakthrough

It seems that this blog was based on a false alarm. If I ever decide to blog seriously about particle physics, I might want to start over. However, for now I shall at least note the slowly spreading attention to Alejandro Rivero's great discovery.

Slightly unorthodox supersymmetry

Matt Strassler again: ways that reality might depart from the most common three assumptions about the phenomenology of supersymmetry. (For very unorthodox supersymmetry, see here.)

More Higgs

Matt Strassler, reporting on a Mumbai conference: "Most interesting result from Tevatron: both CDF and D0 see an excess of events consistent with a supersymmetric Higgs particle in the mass range 120-150 GeV, in a production mechanism that is absent in the Standard Model. (Experts: this is b-quark plus Higgs, where Higgs decays to b-quark and b-antiquark) However this is a tough measurement and it is hard to know whether to trust this… and the excesses are not that large. (And Higgs decay to taus is not observed with a b.)"

Higgs

Hello world, it's been a while, hasn't it? This blog went into hibernation once it began to look like there was no phenomenon to explain, just a glitch in the modeling of background events. But I will now rouse it from its slumbers to report a few things.

At the moment, the search for the Higgs boson is the center of attention. Lubos Motl likes the idea of one Higgs at 115 GeV and another at 144 GeV, as indicative of supersymmetry. But meanwhile I shall report a paper which instead seeks to explain two such Higgses in terms of a composite model; and another which explains the Tevatron data in terms of a two-Higgs model. But first let us see what the LHC says after a few more months.

Task force

John Terning: "A task force is set up to get to the bottom of the discrepancy. The task force will include Fermilab theorists Estia Eichten and Keith Ellis."

Tropical interlude

While we wait for more information, here's Mina Aganagic on the other ostensible topic of this blog, tropical geometry.

Is it real? 2

CDF says it's real, D0 says it isn't. What's going on?

Phil Gibbs: "The differences are too subtle to see from just the visual image, and it does not help that they used different bins. There does appear to be significant differences in the backgrounds while the data look quite similar. If that is the case then the problem is purely theoretical and they just need to compare their background calculations. However, the detectors are different so perhaps the backgrounds should not look exactly the same. Only the people directly involved have enough details to get to the bottom of it."

Georgios Choudalakis (a member of CERN's ATLAS collaboration): "Since the 1st day, I was telling CDF they should re-examine their background, re-consider how systematics are taken into account, and not interpret the discrepancy as a Gaussian, because that was a biased interpretation, perfect to mislead theorists. The BumpHunter was telling me that the most discrepant excess was not a Gaussian, as claimed by CDF, but a broad excess between 120 and 250 GeV, which is the range where the background had a high slope. This was very strongly suggesting that the background was not centered right."

t prime and b prime

Jester suggests that the CDF bump might arise from a 300 GeV resonance which decays to a 150 GeV resonance. In comments, Daniel de França suggests that this could be one fourth-generation quark (t') decaying to another fourth-generation quark (b'). Alas, this very straightforward idea may be inconsistent with existing lower bounds on the mass of a fourth generation.

Dark matter

"Light dark matter in leptophobic Z' models". "Dark Forces At The Tevatron". And see the last paragraph of "Light Z' Bosons at the Tevatron", by the same authors (same, with an error of ±1).

ATLAS blips from TeV-scale strings

Lubos reports the possibility that the CDF bump, and some striking events recorded by ATLAS, might all be explained by TeV-scale strings if the string scale is 2.35 TeV.

Is it real?

Tommaso Dorigo thinks the bump is "a problem in the modeling of backgrounds, one which was unnoticed before only because it is small enough to have escaped previous attempts at "tuning" the simulations". And Pauline Gagnon of CERN reports that ATLAS didn't see anything at that energy in 2010. But ATLAS this year has already generated ten times as much data as it did last year; so really we should just wait for an assessment based on this year's observations.

Other anomalous observations

Lubos Motl made a list of recent claims of BSM (beyond standard model) physics, and asked whether there are any papers out there which can explain at least two of these observations. I find especially interesting "A unified, flavor symmetric explanation for the t-tbar asymmetry and Wjj excess at CDF" by Nelson et al. There's no leptophobic Z' boson here, instead there's a flavor symmetry and new scalar fields. It's a little messy, but the first implementation of a new idea often is, so it would be of interest to understand the essence of how the model does its thing.

Elsewhere in Lubos's list, there's a bump at 325 GeV. What's quite interesting is that a bump around 325 GeV has been observed under two separate circumstances. A discussion with Tommaso Dorigo highlights the obvious reason why they "shouldn't" be the same particle. Still, physics has many possibilities, so maybe there's a way around this. If I was making a model with four generations, I'd start here.

Finally, although the initial claim of a 115 GeV Higgs at the LHC was not endorsed by the rest of the collaboration, it's an attractive value for theoretical reasons. So, if I was just trying to make a field theory model of what we see in our colliders, I guess I'd be looking for a four-generation model a la Lebed and Mayes, which generalized Nelson et al's mechanism, and which had a 115 GeV Higgs. In fact, I have no idea if all those proposals can coexist. But that's part of how theoretical progress occurs - you see if you can fit several things at once into your model, and either you can, or you can't, or you first have to change something...

Instant update

That didn't take long... A very brief investigation into the concept of tropical geometry revealed impressionistic connections to both the relatively orthodox approaches to real-world physics that I am investigating, and one of the wilder speculations that I have my eye on. If the idea was to learn something and to obtain a starting point for extended (beyond-standard-model) phenomenology, then that's mission accomplished already.

Hello world

Hello world. This blog has been created in order to document the results of an exercise in creative absurdity.

Today the physics blogs carry the news that a bump in the data, indicative of a new particle, which was reported last month, has now been confirmed at almost "5-sigma" significance. The most obvious interpretation is that it is a new neutral boson - generically called a Z' boson, since the Z is the known neutral boson - but one that is "leptophobic", coupling to quarks but not to leptons.

As a quasi-amateur physicist only just venturing into particle phenomenology, I'm still trying to settle on an approach which gives us back the Standard Model. I'm not ready for a new particle! More precisely, I have no "intuition" about what this might be, no guiding theoretical preference.

So here is where "absurdity" can help. It turns out that Leptophobia, as well as being an aversion to leptons, is a type of butterfly: a "neotropical genus", the Encyclopedia of Life informs me.

But I have noticed, in the physics preprints, an occasional reference to something called "tropical geometry" (about which I know nothing). And "genus" has a number of mathematical meanings, such as the number of "handles" on a topological object. Anyone familiar with Kaluza-Klein models and compactifications in string theory will understand that such topological properties of the extra dimensions can determine basic features of observable physics.

So here is the absurd premise of this blog: We shall explore the idea that the leptophobia of our new Z' boson (if that is what it is) has something to do with the genus of a tropical (or "neo-tropical") geometry in the hidden dimensions of space-time.

It is at least a way to learn some new mathematics, and to begin thinking about this new phenomenon.