Wednesday, September 21, 2016

Nanopoulos' and pals' model is back to conquer the throne

Once upon a time, there was an evil witch-and-bitch named Cernette whose mass was \(750\GeV\) and who wanted to become the queen instead of the beloved king.

Fortunately, that witch-and-bitch has been killed and what we're experiencing is
The Return of the King: No-Scale \({\mathcal F}\)-\(SU(5)\),
Li, Maxin, and Nanopoulous point out. It's great news that the would-be \(750\GeV\) particle has been liquidated. They revisited the predictions of their class of F-theory-based, grand unified, no-scale models and found some consequences that they surprisingly couldn't have told us about in the previous 10 papers and that we should be happy about, anyway.

First, they suddenly claim that the theoretical considerations within their scheme are enough to assert that the mass of the gluino exceeds \(1.9\TeV\),\[

m_{\tilde g} \geq 1.9\TeV.

\] This is an excellent, confirmed prediction of a supersymmetric theory because the LHC experiments also say that with these conventions, the mass of the gluino exceeds \(1.9\TeV\). ;-)

Just to be sure, I did observe the general gradual increase of the masses predicted by their models so I don't take the newest ones too seriously. But I believe that there is still some justification so the probability could be something like 0.1% that in a year or two, we will consider their model to be a strong contender that has been partly validated by the experiments.

In the newest paper, they want the Higgs and top mass to be around\[

m_h\approx 125\GeV, \quad m_{\rm top} \approx 174\GeV

\] while the new SUSY-related parameters are\[

\tan\beta &\approx 25\\
M_V^{\rm flippon}&\approx (30-80)\TeV\\
M_{\chi^1_0}&\approx 380\GeV\\
M_{\tilde \tau^\pm} &\approx M_{\chi^1_0}+1 \GeV\\
M_{\tilde t_1} &\approx 1.7\TeV\\
M_{\tilde u_R} &\approx 2.7\TeV\\
M_{\tilde g} &\approx 2.1\TeV

\] while the cosmological parameter \(\Omega h^2\approx 0.118\), the anomalous muon's magnetic moment \(\Delta a_\mu\approx 2\times 10^{-10}\), the branching ratio of a bottom decay \(Br(b\to s\gamma)\approx 0.00035\), the muon pair branching ratio for a B-meson \(Br(B^0_s\to \mu^+\mu^-)\approx 3.2\times 10^{-9}\), the spin-independent cross section \(\sigma_{SI}\approx (1.0-1.5)\times 10^{-11}\,{\rm pb}\) and \(\sigma_{SD} \approx (4-6)\times 10^{-9}\,{\rm pb}\), and the proton lifetime\[

\tau (p\to e^+ \pi^0) \approx 1.3\times 10^{35}\,{\rm years}.

\] Those are cool, specific predictions that are almost independent of the choice of the point in their parameter space. If one takes those claims seriously, theirs is a highly predictive theory.

But one reason I wrote this blog post was their wonderfully optimistic, fairy-tale-styled rhetoric. For example, the second part of their conclusions says:
While SUSY enthusiasts have endured several setbacks over the prior few years amidst the discouraging results at the LHC in the search for supersymmetry, it is axiomatic that as a matter of course, great triumph emerges from momentary defeat. As the precession of null observations at the LHC has surely dampened the spirits of SUSY proponents, the conclusion of our analysis here indicates that the quest for SUSY may just be getting interesting.
So dear SUSY proponents, just don't despair, return to your work, and get ready for the great victory.

Off-topic: Santa Claus is driving a Škoda and he parks on the roofs whenever he brings gifts to kids in the Chinese countryside. What a happy driver.

No comments:

Post a Comment