Unapproved results from the LHC: preview of the next 6 months

Last talk of the LHC Shows the Way workshop, with the most provocative title.

Entries in this post may or may not be mangled misrepresentations of stuff the speaker made up just to be provocative...

Starting point: there is something at ~ 125 GeV and it is consistent with a boson, possibly a scalar, and quite likely a standard model Higgs boson.

Preliminary results for CMS experiments show branching ratio to ττ decay mode a little bit lower than normal.
ATLAS initially did simple crude analysis of this channel.
Now redone with more data and better technique.
ATLAS expect to make statement as soon as end of August on this channel.
Specifically what the coupling of the 125 GeV scalar is to fermionic decay modes.

This will either open up new turf or push everything into the standard model.

About 10 meetings per day within LHC collaboration on Higgs scenarios.

Are there excesses in the γγ channel at ATLAS?
With missing energy?

We are shown a partial plot, of the data not to be shown publicly, with axis labels missing, but with error bars.

Statistically insignificant as yet, but there is some hint of an excess at a particular mass... this could be interesting with an order of magnitude more data. Which they will have.

Could there be multiple Higgs, with the decay modes hiding in the data? Yes there could. Yes they can look. Maybe they can see them if they are there. Hard as more parameters are added.

Could see second Higgs at few hundred GeV IF it is there.

Next: Dark Matter - Mono-Anything?

Hoping to get cascade to dark matter WIMP (or channel through supersymmetric sector, but not talking about that today).

Look for mono-jets - one sided particle jet with presumably a dark matter WIMP going off undetected in the opposite direction.
For obvious reasons double WIMP modes are hard to detect...

Can also look for multi-jet events with missing energy and missing momentum no co-aligned with the known jets (to filter out calibration errors etc).

Neutrino jets from Z decay gives similar events, need to be filtered out etc.
So any signal is hidden in know standard model events that need to be accurately calibrated out.

So far mono-jets consistent with standard model events.
Upper limit on WIMP production, modulo assumptions about coupling strengths and function of spin states etc.
Sensitive in the 10-100 GeV range if I read graph axis labels right. Complementary to many ground based elastic scattering direct detection experiments.

Modulo couplings it puts lower mass limit on the supersymmetric boson as a function of the limit on the least massive supersymmetric particle.
Model dependent but broadly consistent.

Interesting discussion on how experimental results are communicated and then interpreted by theorists.
Some of the same problem we have in astro - quite often it is possible to reanalyse same data but better (as opposed to reanalyse old+new data with NEW selection procedures), but it is boring, no one wants to do it and it is very hard to publish.
So not done.
So real constraints are not well communicated and partial obsolete results get stuck in theory which leads to unnecessary speculative theory papers which are actually already ruled out.

So, clearly, the status quo is a WIN-WIN.

Some examples are shown on upper limits to conjectured particles.

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No questions about 125 GeV WIMP, 125 GeV Higgs?

By Derek Fox (not verified) on 09 Aug 2012 #permalink