The last session of the day, and the halfway point as far as parallel talks go. This time I'm staying in a single place, the BSM Higgs session.
4:30 pm: Higgs Mass from Compositeness at a Multi-TeV Scale, Jiayin Gu
NJL model is nice but, as well known for decades, does not work. Minimal extension: add a vector-like top partner. Impose SU3L symmetry to generate Higgs mass with little work.
End up with two Higgs triplets, so model is essentially two Higgs (doublet + singlet). Singlets somewhat heavy; most of chiral symmetry breaking f lies in their VEVs. This is a requirement from the lack of a custodial symmetry: top partners are expected to be too heavy to observe at the LHC.
Extending the model to include a custodial symmetry makes things much uglier, but now f is smaller and the top partners are observable.
4:45 pm: Warped Flavour, 126 GeV Scalar and the 100 TeV Collider, Amarjit Soni
Flavour constraints have, for a long time, told us that new physics does not lie at 1 TeV. In this sense, the Higgs measurements are not a surprise.
Warped models are models of flavour, and suppress the NP scale by ~ 1000, to 10 TeV.
First point: Higgs doublet can itself stabilise extra dimension, removing need for Goldberger-Wise mechanism. Fitting Higgs couplings points to KK gluon mass at 5 TeV.
There's a lot of review of RS models here. I guess Amarjit feels people have stopped talking about these models or something.
The 5pm talk is delayed till tomorrow, so we get a short break!
5:15 pm: The Decoupling Limit in the Georgi-Machacek Model, Kathryn Hartling
Model contains one doublet plus two triplets, which are combined to make the SU2 custodial symmetry manifest. Allows hVV to increase, difficult to achieve in most models.
Usual model does not have a decoupling limit, due to the use of a Z2 symmetry to simplify the scalar potential. (Unitary bounds pose upper limits on masses.) Hence, we need to drop that symmetry to see if a decoupling limit exists. Does the model approach SM when the mass parameters become large?
The answer is yes. The decoupling behaviour is quite different to comparable models, but in particular the leading correction to the hVV coupling is positive (and negative for hff).
5:30 pm: Indirect Effects of the Triplet Extension of the MSSM, Bryan Ostdiek
Like the NMSSM, but the extra scalar is a triplet rather than a singlet. Like there, adding extra scalars to raise the Higgs mass at tree level. Assume the triplet does not gain a VEV (so as to avoid T parameter constraints).
The motivation is getting the charged scalars, so we are back to the h to γγ anomaly. One of the original papers on this noted an odd effect: a decoupling-limit like effect where the pseudoscalar mass is actually very low. This talk is about the phenomenology of those model points.
'Indirect' means stop couplings. Some nice plots showing comparisons of scalar triplets and the Wino, a fermion triplet.
Question: Landau poles? Around 10^8 TeV for the points considered here. Low, but not too bad for these types of models.
5:45 pm: The Bestest Little Higgs Model in a Post-Higgs Era, Travis Martin
Precision constraints meant the "simple" LH models would be insensitive to the LHC. The B2LH model may be the exception, because of its more esoteric construction that makes it less sensitive to these constraints. Hence the question is how the model looks like now.
Type I 2HDM, so constrains on charged Higgs much reduced due to not coupling to fermions. Higgs couplings loop corrected by new scalars/fermions, of which there are a lot. Consider both the possibility of the future Higgs measurements being SM or like, or SM like with a diphoton excess.
Higgs measurements seem to want the Higgs and pseudoscalar to differ in mass by at least 200 GeV; this is due to the coupling to τ, which is enhances as the pseudoscalar does not decay to gauge bosons.
6:00 pm: Electroweak-Scale Right-Handed Neutrino Model, 126 GeV Higgs Boson and BSM Scalars, Ajinkya Kamat
Model with EW-scale right-handed neutrinos, to give testable generation of neutrino masses. Have essentially a copy (modulo neutrinos) of SM. Lepton doublet of partner contains NR (so light), other states needed for anomalies. Corresponds to enhancing gauge symmetry to SU2L x SU2R. Then things get horribly messy to break that symmetry, not screw you over with the Higgs-gluon couplings, ouch.
6:15 pm: A 125-GeV Higgs and the μ-less MSSM, Jessica Goodman
If the MSSM has no μ-term (no dimensionful terms) it will always have a massless gaugino. This is solved by generating Dirac gaugino masses through supersoft operators. This in turn involves breaking a hidden sector U1.
Unfortunately, it seems this doesn't ultimately work; we still need an effective mu term (e.g. from giving VEVs to some scalars). This in turn leads to a problem getting the Higgs mass low enough (!) without having charginos that are too light.
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