13,510 research outputs found
The light Higgs in supersymmetric models with Higgs triplets
In supersymmetric models the presence of Higgs triplets introduce new quartic
interactions for the doublets that may raise the mass of the lightest CP-even
field up to 205 GeV. We show that the complete effect of the triplets can be
understood by decoupling them from the minimal sector and then analyzing the
vacuum and the spectrum of the two-Higgs doublet model that results. We find
that the maximum value of m_h is only achieved in a very definite region of the
parameter space. In this region, however, radiative corrections decrease the
bound to 190 GeV.Comment: 10 pages, 1 figur
Preserving the validity of the Two-Higgs Doublet Model up to the Planck scale
We examine the constraints on the two Higgs doublet model (2HDM) due to the
stability of the scalar potential and absence of Landau poles at energy scales
below the Planck scale. We employ the most general 2HDM that incorporates an
approximately Standard Model (SM) Higgs boson with a flavor aligned Yukawa
sector to eliminate potential tree-level Higgs-mediated flavor changing neutral
currents. Using basis independent techniques, we exhibit robust regimes of the
2HDM parameter space with a 125 GeV SM-like Higgs boson that is stable and
perturbative up to the Planck scale. Implications for the heavy scalar spectrum
are exhibited.Comment: 36 pages, 4 figures, 4 tables (Version 3: typographical error in eq.
(A.28) corrected
Relativistic Quantum Thermodynamics of Ideal Gases in 2 Dimensions
In this work we study the behavior of relativistic ideal Bose and Fermi gases
in two space dimensions. Making use of polylogarithm functions we derive a
closed and unified expression for their densities. It is shown that both type
of gases are essentially inequivalent, and only in the non-relativistic limit
the spinless and equal mass Bose and Fermi gases are equivalent as known in the
literature.Comment: 6 pages, 1 figur
Implications of symmetries in the scalar sector
Symmetries play a very important r\^ole in Particle Physics. In extended
scalar sectors, the existence of symmetries may permit the models to comply
with the experimental constraints in a natural way, and at the same time reduce
the number of free parameters. There is a strong interplay among internal
symmetries of the scalar potential, its CP properties and mass degeneracies of
the physical scalars. Some of these aspects were discussed in this talk.Comment: 8 pages, to be published in the Proceedings of DISCRETE2018: 6th
Symposium on Prospects in the Physics of Discrete Symmetries, 26-30 Nov 2018.
Vienna, Austri
Symmetries and Mass Degeneracies in the Scalar Sector
We explore some aspects of models with two and three SU(2) scalar doublets
that lead to mass degeneracies among some of the physical scalars. In Higgs
sectors with two scalar doublets, the exact degeneracy of scalar masses,
without an artificial fine-tuning of the scalar potential parameters, is
possible only in the case of the inert doublet model (IDM), where the scalar
potential respects a global U(1) symmetry that is not broken by the vacuum. In
the case of three doublets, we introduce and analyze the replicated inert
doublet model, which possesses two inert doublets of scalars. We then
generalize this model to obtain a scalar potential, first proposed by Ivanov
and Silva, with a CP4 symmetry that guarantees the existence of pairwise
degenerate scalar states among two pairs of neutral scalars and two pairs of
charged scalars. Here, CP4 is a generalized CP symmetry with the property that
is the identity operator only for integer values that are
multiples of 4. The form of the CP4-symmetric scalar potential is simplest when
expressed in the Higgs basis, where the neutral scalar field vacuum expectation
value resides entirely in one of the scalar doublet fields. The symmetries of
the model permit a term in the scalar potential with a complex coefficient that
cannot be removed by any redefinition of the scalar fields within the class of
Higgs bases (in which case, we say that no real Higgs basis exists). A striking
feature of the CP4-symmetric model is that it preserves CP even in the absence
of a real Higgs basis, as illustrated by the cancellation of the contributions
to the CP violating form factors of the effective ZZZ and ZWW vertices.Comment: 52 pages, 2 figures, second revised version with new material, as
published by JHE
Mass-degenerate Higgs bosons at 125 GeV in the Two-Higgs-Doublet Model
The analysis of the Higgs boson data by the ATLAS and CMS Collaborations
appears to exhibit an excess of h --> gamma\gamma events above the Standard
Model (SM) expectations; whereas no significant excess is observed in h --> ZZ*
--> {four lepton} events, albeit with large statistical uncertainty due to the
small data sample. These results (assuming they persist with further data)
could be explained by a pair of nearly mass-degenerate scalars, one of which is
a SM-like Higgs boson and the other is a scalar with suppressed couplings to
W+W- and ZZ. In the two Higgs doublet model, the observed \gamma\gamma and ZZ*
--> {four lepton} data can be reproduced by an approximately degenerate CP-even
(h) and CP-odd (A) Higgs boson for values of \sin(\beta-\alpha) near unity and
0.7 < \tan\beta < 1. An enhanced \gamma\gamma signal can also arise in cases
where m_h ~ m_H, m_H ~ m_A, or m_h ~ m_H ~ m_A. Since the ZZ* --> {four lepton}
signal derives primarily from a SM-like Higgs boson whereas the \gamma\gamma
signal receives contributions from two (or more) nearly mass-degenerate states,
one would expect a slightly different invariant mass peak in the ZZ* --> {four
lepton} and \gamma\gamma channels. The phenomenological consequences of such
models can be tested with additional Higgs data that will be collected at the
LHC in the near future.Comment: 18 pages, 19 pdf figures, v2: references added, v3&v4: added refs and
explanation
Radio Frequency Interference /RFI/ design guide for aerospace communications systems
Radio frequency interference design guide for aerospace communications system
On Bose-Einstein condensation on closed Robertson-Walker spacetimes
In this letter we summarize our analysis of Bose-Einstein condensation on
closed Robertson-Walker spacetimes. In a previous work we defined an adiabatic
KMS state on the Weyl-algebra of the free massive Klein-Gordon field. This
state describes a free Bose gas on Robertson-Walker spacetimes. We use this
state to analyze the possibility of Bose-Einstein condensation on closed
Robertson-Walker spacetimes. We take into account the effects due to the
finiteness of the spatial volume and show that they are not relevant in the
early universe. Furthermore we show that a critical radius can be defined. The
condensate disappears above the critical radius.Comment: 9 pages, 1 figure, uses elsart.cl
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