Les Houches
2023 Session
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- Use of wiki pages and slack. Wifi access/set-up.
- Important info about bus, lodging, facilities.
- Bulletins.
Wikis of Previous sessions
Les Houches Themes
(Lyrics and Music)
(Lyrics and Music)
This is an old revision of the document!
Responsible: Ken Lane
Participants: Ken & Jon B + Will Shepherd + David Sperka
=== Notes on Parameters === edited by Ken Lane on 27 October, 2019; edits indicated by KL:
KL: The definition of $\sin(\beta-\alpha)$ is inverted in this file compared to usual convention of Branco et al., so the alignment limit is achieved when $\sin(\beta-\alpha) = 0$ (It is $\sin(\beta-\alpha) = 1$ in the standard definition of Branco et al. b/c they define the \rho_1–\rho_2 → h,H (= h1,h2 below) mixing angle \alpha as \pi/2 in the alignment limit. KL & Will Shepherd defined \alpha = \beta in the alignment limit b/c it is in line with the Higgs h1 = H(125) being a Goldstone boson of spontaneous scale symmetry breaking. Thus, in the KL-WS convention, \sin(\beta - \alpha) = \sin\delta where \delta is the misalignment angle in their paper, PRD 99, 055015 (2019), \delta = 0in the alignment limit – which is tree approximation in the GW-2HDM.).
An example of the Higgs branching ratios for these settings is here:lhc-s101-runpoint_0100.log.txt KL: These June 30, 2019, BR's are out of date and incorrect.
It can be seen that the branching ratio to $b$ quarks is about 80%, so higher than the SM value. This seems to be due the fact that Herwig is LO and does not use a running $b$ mass (Ken).
Still do not understand why the $H \rightarrow \gamma\gamma$ branching fraction is zero.
Higgs labelling conventions (left is the UFO name, right the name usually used):
Is $\tan\beta$ the usual definition?
Fix the m(h+/-) and A masses to be equal to $M$ and related to the $H^\prime$ mass via $(540 GeV)^4 = M_{H^\prime}^4 + 3M^4$, and scan over $0.1 < \tan\beta < 10$ and $150 < M < 410$GeV.
As you can see, the measurements disfavour $\tan\beta > 1$ regardless of $M = M_A$. There is some increase in sensitivity at high $M_A$. We can also plot the same data as a function of $M_{H^\prime}$:
The binning is equally spaced in $M$, so gets distorted in $M_{H^\prime}$ (can do another scan in $M_{H^\prime}$ if useful). However, even here we can see the increased sensitivity at high $M_A$ corresponds to $M_{H^\prime} < 250$GeV or so.
We can look at the sensitivity plots for different signatures. The sensitivity that reaches to lowest $\tan\beta$ comes from dilepton+X measurements around the $Z$ pole (so $Z+$jet and similar measurements). See below:
Lepton+MET+X measurements (mostly $W$+jet or top) also have their best sensitivity at quite $M$, but a bit lower than the dileptons, so at intermediate $M_{H^\prime}$, see below the same scan plotted against the two different masses.
The inclusive $\gamma$ measurements also have some sensitivity, which shows a sharp cutoff once $M_A > 350$ GeV. (See below.)
This needs to be understood. Next, we should try and identify exactly which processes and which cross section measurements drive these sensitivities to check whether they makes sense.
Trying this 2HDM: https://feynrules.irmp.ucl.ac.be/wiki/2HDM
Quick test run for 13TeV with these parameters:
set /Herwig/FRModel/Particles/h2:NominalMass 150*GeV set /Herwig/FRModel/Particles/h3:NominalMass 410*GeV set /Herwig/FRModel/Particles/h+:NominalMass 410*GeV set /Herwig/FRModel/Particles/h-:NominalMass 410*GeV set /Herwig/FRModel/FRModel:tanbeta 0.5 set /Herwig/FRModel/FRModel:sinbma 1.0
I think h2 = H', and h3 = A in Ken's language. Not sure which way up $\tan\beta$ is.
Herwig output:
Seems to be some sensitivity in the CMS top and W+jets measurements and the ATLAS Z+jets…to be checked. Note this run is only 1000 events, will do more once we agree whether it looks sensible. Then also plan to fix $[2 M_{h^\pm}^4 + M_{h3}^4 + M_{h2}^4] = 540^4$ GeV and scan in $\tan\beta$ and $M_{h2}$.
Same run but with
set /Herwig/FRModel/FRModel:tanbeta 2.0
Herwig output:
Same as above, swith
set /Herwig/FRModel/FRModel:tanbeta 0.5
Herwig output:
Same as above, still with
set /Herwig/FRModel/FRModel:tanbeta 2.0
Herwig output:
TODO add the resonant modes gg→h2 etc