266 research outputs found
Discrimination of the light CP-odd scalars between in the NMSSM and in the SLHM
The presence of the light CP-odd scalar boson predicted in the
next-to-minimal supersymmetric model (NMSSM) and the simplest little Higgs
model (SLHM) dramatically changes the phenomenology of the Higgs sector. We
suggest a practical strategy to discriminate the underlying model of the CP-odd
scalar boson produced in the decay of the standard model-like Higgs boson. We
define the decay rate of "the non -tagged jet pair" with which we compute
the ratio of decay rates into lepton and jets. They show much different
behaviors between the NMSSM and the SLHM.Comment: 5 pages, 2 figures (5 figure files
Two Higgs Doublets Model in Gauge-Higgs Unification framework
We discuss the realization of two Higgs doublets model in the framework of 6
dimensional Gauge-Higgs Unification model with a simple Lie group G_M. Two
Higgs SU(2)_L doublets can emerge at the low energy effective theory, and the
quartic coupling terms in the scalar potential, essential for the electroweak
symmetry breaking, are now G_M gauge invariant and permissive. A realistic two
Higgs doublets model can possibly be obtained only when two of the root vectors
associated with the would-be Higgs doublets and the root vector for SU(2)_L
form an isosceles triangle with vertex angle either of Pi/3, Pi/2, or 2Pi/3.
Moreover, depending on G_M, the scalar potential of resulting two Higgs
doublets model can admit only a few limited forms. The mass spectrum of the
physical Higgs and the weak mixing angle are briefly discussed.Comment: 5 Pages and 1 figure. Matches published version in PR
Measuring properties of a Heavy Higgs boson in the decay
In many extensions of the standard model, there exist a few extra Higgs
bosons. Suppose a heavy neutral Higgs boson H is discovered at the LHC, one
could then investigate CP and CPT~ properties of its couplings to a pair of
bosons through . We use the helicity-amplitude method to
write down the most general form for the angular distributions of the four
final-state leptons, which can cover the case of CP-even, -odd, and -mixed
state for the Higgs boson. We figure out there are 9 types of angular
observables and all the couplings to bosons can be fully determined by
exploiting them. A Higgs-boson mass of 260 GeV below the threshold is
illustrated with full details. With a total of events of , one can determine the couplings up to 12-20\% uncertainties.Comment: 23 pages, 4 figures, 3 tables, to appear in JHE
An exact solution of the higher-order gravity in standard radiation-dominated era
We report that the standard evolution of radiation-dominated era (RDE)
universe is a sufficient condition for solving a sixth
order gravitational field equation derived from the Lagrangian containing as well as a polynomial for a spatially
flat radiation FLRW universe. By virtue of the similarity between
and models up to the background order and of the vanishing
property of for , the analytical solution can be
obtained from a special case to general one. This proves that the standard
cosmic evolution is valid even within modified gravitational theory involving
higher-order terms. An application of this background solution to the
tensor-type perturbation reduces the complicated equation to the standard
second order equation of gravitational wave. We discuss the possible ways to
discriminate the modified gravity model on the observations such as the
gravitational wave from the disturbed universe and primordial abundances
Higgs-boson-pair production from gluon fusion at the HL-LHC and HL-100 TeV hadron collider
We perform the most up-to-date comprehensive signal-background analysis for
Higgs-pair production in channel at the HL-LHC
and HL-100 TeV hadron collider, with the goal of probing the self-coupling
of the Higgs boson. We simulate all the standard-model signal
and background processes with the simulation tools almost as sophisticated as
what experimentalists are using. We find that even for the most promising
channel at the HL-LHC with a luminosity of 3000
fb, the significance is still not high enough to establish the Higgs
self-coupling at the standard model (SM) value. Instead, we can only constrain
the self-coupling to at confidence level
after considering the uncertainties associated with the top-Yukawa coupling and
the estimation of backgrounds. Here we also extend the study to the HL-100 TeV
hadron collider. With a luminosity of 3 ab, we find there exists a bulk
region of 2.6 \lsim \lambda_{3H} \lsim 4.8 in which one cannot pin down the
trilinear coupling. Otherwise one can measure the coupling with a high
precision. At the SM value, for example, we show that the coupling can be
measured with about 20 \% accuracy. While assuming 30 ab, the bulk
region reduces to 3.1 \lsim \lambda_{3H} \lsim 4.3 and the trilinear coupling
can be measured with about 7 \% accuracy at the SM value. With all the
simulated background events and results, our study can be useful to probe the
Higgs potential of various models with extended Higgs sector, such as
two-Higgs-doublet model, MSSM, etc.Comment: 35 pages, 21 figures, 15 tables; New section V. FURTHER IMPROVEMENTS
ENVISAGED added, Tables VI and XII updated, references added; New Appendix C
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