I know Janet well, and she is a sort of taliban of neutrinos Seriously, she would have been my first choice had one asked me to name somebody who thought that neutrino masses were evidence of BSM physics. But things are not as simple as she paints them. The SM is still there, and as I said somewhere in this blog already (here),

“The neutrino masses force an extension of the Standard Model more or less as revolutionary as a rearrangement of the furniture in the kids’ room forced by the arrival of a new baby.“

Cheers,
T.

“Neutrinos vs. the Standard Model: Because Goliath Lost!”
Prof. Janet Conrad
Over years, physicists developed a “Standard Model” of particle physics which describes the data very well. It correctly predicted the results of nearly all particle physics experiments. Now we think the tiniest matter particle, the neutrino, shows a chink in the Standard model. This talk describes the discovery of neutrino mass and discusses the next steps in neutrino physics world-wide and at LNS.

Cheers,
T.

I think the D0 measurement is 2.3+-0.7, not 2.6.
In a sense, yes, it is an indication that D0, were to do the same analysis, would probably find some excess too. However, while CDF has measured the bb xs with both SVX and dimuons, D0 has done it only with dimuons. If D0 found a number close to NLO with secondary vertices, that alone would be some indication that they too have a unknown extra source of muons.

Whether that is new physics or some screwup in the simulation of energy loss and other effects in the material, is not granted though.

Cheers,
T.

I have a question:
As far as I know, one of the motivations that led to the observation of this unexpectedly large sample of events with muons at CDF was the measurement of discrepant bb cross sections (I mean, discrepant with respect to the SM predictions).
In the paper by the CDF collaboration published in Phys. Rev. D 77, with reference 072004 (the one in that the “tight SVT cuts” are applied), I read that not only CDF reported a measurement of R2b (the ratio of the measured bb cross section to the exact NLO prediction) unexpectedly large (3.0+/-0.6), but also D0 (2.6+/-0.7).
As I understand (according to the paper just released by CDF), the origin of this value of R2b (at CDF) are the “ghost muons” that in a posterior analysis are cutted by the “tight SVT cuts”. And my question is: Does the fact that there has been another (independent, I supose) measurement of R2b at D0 consistent with the one obtained by CDF support the idea that the observed “ghost muon sample” is really new physics, and not a failure in the analysis?
Thank you very much,

Elías

as far as your second question is concerned, I can answer it straight away: although not a rigorous procedure, the tail of the impact parameter distribution can be fit with , extracting the particle’s with good precision, regardless of the particle’s momentum spectrum. That is because the impact parameter remains invariant for lorentz boosts: the larger the , the longer the particle travels (by a distance ), and d scales accordingly.

As for your first question, I have an answer for you, but I prefer to check it with the author of the analysis, because there might be a subtlety and I do not want to mislead you, given that you will be making use of the information. I will get back to you shortly on that.

Cheers,
T.

I was reading Neal Stephenson’s new book and he mentions “quantum cross-talk” as a mechanism for the transfer of data between discrete cosmi in a polycosmic interpretation of the universe.

I happen to look up at a stupid poster of moon phases on the wall, and realize that if such a thing actually existed, higher density regions (like neutron stars) would have the greatest cross-talk. So I google “quantum cross talk” and get this blog.

Now. I only understand every 6th word you guys are babbling on about, but you seem to be talking about verified (sort of) tests that witness extra muons popping into this cosmos without source?

And, to make it worse, 80% of you are using avatar icons representing tiling problems, just like Stephenson’s obsessive polycosmos “Lineage” cult dudes.

Damn it, damn it.

Please try to avoid collapsing this cosmos into a singularity.

I am trying to digest the paper for a discussion in our group in A’dam and I have two burning questions:
- How is the QCD contribution subtracted to obtain the ‘ghost’ distribution for muon impact parameters in figure 7 (the first figure above)? And for example for the D0 invariant mass in figure 4?
- To obtain a lifetime from the distributions in figure 26 (last pictures shown above), you’ll need a momentum measurement. How is the momentum of these candidates estimated? This is not described in the paper.

Thanks a lot,
Wouter