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2017:groups:tools:contur

This is an old revision of the document!


Information on Contur-related projects

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2HDM Studies

Kristin Lohwasser, Ken Lane, Jon Butterworth, David Grellscheid, Lukas Pritchett, …

First look with default parameters

Made in Les Houches, Masses as below, Beta = 0.0813, MixH = 0.0883

Proposed parameter scan from Ken

Start with:

  • m(h_1) = 125 GeV
  • m(h_2) = 30 GeV
  • m(h_3) = 30 GeV
  • beta = arcsin(v2/246 GeV) = 0.05084 for v2 = 12.5 GeV (and = 0.08139 20 GeV, if you feel ambitious)
  • mixh = beta - alpha for alpha = -0.435 x 10^{-2} (and -0.695 x 10{-2} for v2 = 20 GeV; ditto)

The signal processes of interest are:

$$\begin{aligned} \bar{q} q \rightarrow \gamma, Z \rightarrow h^+ h^- \rightarrow \mu^+ \mu^- + E_T^{\rm missing} \\ \bar{d} u \rightarrow W^+ \rightarrow h^+ h_2 \ {\rm AND}\ h^+ h_3 \rightarrow \mu^+ \mu^+ \mu^- + E_T^{\rm missing}, \\ {\rm (plus\ charge\ conjugate\ )} \\ \bar{q} q \rightarrow Z \rightarrow h_2 h_3 \rightarrow \bar{b} b \mu^+ \mu^-\end{aligned}$$

For these, you want to scan over $h^+$ mass from 95 GeV to 250 GeV.

Update from Jon 18 Sept

Here's a first look, for inclusive $h^+$ or $h^-$ production, 8 TeV, parameters as above and beta = 0.0508, mixh = 0.0547 and $m(h^{+/-}) = 100$ GeV.

Total cross section 1.8 pb.

Note that the ATLAS 4l result still has a lot of exclusion power, even though the $h_2 h_3$ production channel is switched off (with this switched on, the total cross section is ~346 pb). From looking at the Herwig logs, I think this contribution may come from events like $q\bar{q} \rightarrow h_2 h^+ \rightarrow h_2 h_3 \mu \nu$ with subsequent $h_2, h_3$ decays to muons.

However, you can see that the ATLAS WW measurement also has some exclusion - about 92%. I don't understand why the CMS H->WW one doesn't have an exclusion anywhere in the same league. Either the Higgs selection cuts suppress it or there is a bug/feature in the rivet routine (either ATLAS or CMS!). I will look into it.


Light Scalar Particles

Susan Shotkin Gascon-Shotkin, Linda Finco, Sijing Zhang, Grégory Moreau, Peter Richardson, Sylvain Fichet, David Grellscheid, Jon Butterworth, David Yallup…

Joint with Higgs group.

Herwig status

Herwig not dealing with UFO file properly. PR aiming to fix the 3D vertex. This is now fixed. Peter has implemented the relevant vertices in Herwig/ThePEG and its UFO interface, and validated the cross section against MadGraph. This is not yet in 7.1.1 but is in the Herwig 7 trunk in the repository, hopefully in next release. The exception is the 5-point vertices which are used in the CP-even model:

 Warning: Lorentz structure VVVVS ( g g g g phiNP ) in V_49 is not supported.
 Warning: Lorentz structure VVSSS ( W- W+ H H phiNP ) in V_118 is not supported.
 Warning: Lorentz structure VVVVS ( a a W- W+ phiNP ) in V_122 is not supported.
 Warning: Lorentz structure VVVVS ( W- W- W+ W+ phiNP ) in V_126 is not supported.
 Warning: Lorentz structure VVVVS ( a W- W+ Z phiNP ) in V_150 is not supported.
 Warning: Lorentz structure VVSSS ( Z Z H H phiNP ) in V_156 is not supported.
 Warning: Lorentz structure VVVVS ( W- W+ Z Z phiNP ) in V_160 is not supported.

These are currently ignored - hope they aren't a major effect (they don't look like they should be…)

Some (preliminary!) results with Contur

Suggested parameter ranges from Sylvain:

 CP-even scalar:
 mphi in [10, 100] GeV
 f0B in [1, 10] TeV
 f0W in [1, 10] TeV
 f0H in [1, 10] TeV
 CP-odd scalar:
 mphi in [10, 100] GeV
 f0B in [1, 10] TeV
 f0W in [1, 10] TeV
 For each case, all the other f's should be set to very large values. 

So, here is a scan using these ranges for the CP-odd scalar model (f0 value labelled $\Lambda$ on the vertical axis, $M_\phi$ on the horizontal.

… so this is looking pretty promising. Everything excluded except the lowest mass/highest scale. This needs to be carefully checked, of course. All the yellow region above is excluded by the ATLAS diphoton cross sections: arXiv:1704.03839. If those are not included, the ATLAS $Z+\gamma$ measurements (in dilepton+photon and MET+photon) have quite some power on their own, see below.

Z+photon

Missing ET + photon

Remember, big caveat on this is that the data is assumed to exactly agree with the SM, which means (given we only really know that these data are consistent with the SM) that we are neglected the SM theory uncertainties.

Older Stuff

Not really sure of what sensible parameter ranges would be at the moment, but here is an example run for CP-Odd scalar with some 8 TeV data. I (Jon) set $m_\phi = 80$ GeV, and setting the mass scales for the effective couplings at 50 or 100 TeV as follows: $f0B, f0W, f0H, f0gam, f0Z = 50$ TeV, $f0G, f0u, f0d, f0l = 100$ TeV. Total cross section is $4.4 pb^{-1}$.

The Contur “exclusion” for these parameters with the 8 TeV measurements currently in Rivet is at 77% cl. The exclusion dominantly comes from the ATLAS diphoton cross sections: arXiv:1704.03839. The comparison plots are here for 7 TeV 8 TeV. You can see that the most significant exclusion is from the mass peak, though many other differential cross sections show a significant effect (they are not all combined, since they are the same events - only the most significant contributes to the overall c.l.)

I also made a run where I increased the couplings to weak bosons by setting $f0B, f0W, f0H, f0Z = 5$ TeV, just to see what happens. I also turned off the $\phi$+jet process, to focus on the electroweak-type signatures. The exclusion is now at 97% c.l., dominated by the ATLAS $W/Z + \gamma$ measurement. The results are here for 7 TeV and 8 TeV (8 TeV is by far the most interesting).

(Modulo BR changes, the exclusion from the diphotons would presumably still be similar to the above, since the production cross section is driven by $f0G$ which didn't change. This could be combined with the 97%, as the events are independent.)

Next step? Agree some sensible parameter ranges to scan, presumably mass and some subset of couplings; I can combine 7, 8 and 13 TeV limits, of course.

2017/groups/tools/contur.1505982247.txt.gz · Last modified: 2017/09/21 10:24 by jonathan.butterworth