Abstract This work investigates a simple, representative extension of the Standard Model with a real scalar singlet and spontaneous Z 2 breaking, which allows for a strongly first-order phase ...transition, as required by electroweak baryogenesis. We perform analytical and numerical calculations that systematically include one-loop thermal effects, Coleman-Weinberg corrections, and daisy resummation, as well as evaluation of bubble nucleation. We study the rich thermal history and identify the conditions for a strongly first-order electroweak phase transition with nearly degenerate extrema at zero temperature. This requires a light scalar with mass below 50 GeV. Exotic Higgs decays, as well as Higgs coupling precision measurements at the LHC and future collider facilities, will test this model. Additional information may be obtained from future collider constraints on the Higgs self-coupling. Gravitational-wave signals are typically too low to be probed by future gravitational wave experiments.
125 GeV Higgs boson and the type-II seesaw model Dev, P. S. Bhupal; Ghosh, Dilip Kumar; Okada, Nobuchika ...
The journal of high energy physics,
03/2013, Letnik:
2013, Številka:
3
Journal Article
Abstract We propose a minimal A 4 flavor symmetric model, assisted by Z 2 × Z 3 symmetry, which can naturally takes care of the appropriate lepton mixing and neutrino masses via Type-I seesaw. It ...turns out that the framework, originated due to a specific flavor structure, favors the normal hierarchy of light neutrinos and simultaneously narrows down the range of Dirac CP violating phase. It predicts an interesting correlation between the atmospheric mixing angle and the Dirac CP phase too. While the flavor structure indicates an exact degeneracy of the right-handed neutrino masses, renormalization group running of the same from a high scale is shown to make it quasi-degenerate and a successful flavor leptogenesis takes place within the allowed parameter space obtained from neutrino phenomenology.
A FB in the SMEFT: precision Z physics at the LHC Bresó-Pla, Víctor; Falkowski, Adam; González-Alonso, Martín
The journal of high energy physics,
08/2021, Letnik:
2021, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A
bstract
We study the forward-backward asymmetry
A
FB
in
pp → ℓ
+
ℓ
−
at the
Z
peak within the Standard Model Effective Field Theory (SMEFT). We find that this observable provides per mille level ...constraints on the vertex corrections of the
Z
boson to quarks, which close a flat direction in the electroweak precision SMEFT fit. Moreover, we show that current
A
FB
data is precise enough so that its inclusion in the fit improves significantly LEP bounds even in simple New Physics setups. This demonstrates that the LHC can compete with and complement LEP when it comes to precision measurements of the
Z
boson properties.
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