6,744 research outputs found
The light CP-even MSSM Higgs mass resummed to fourth logarithmic order
We present the calculation of the light neutral CP-even Higgs mass in the
MSSM for a heavy SUSY spectrum by resumming enhanced terms through fourth
logarithmic order (NLL), keeping terms of leading order in the top Yukawa
coupling , and NNLO in the strong coupling . To this goal,
the three-loop matching coefficient for the quartic Higgs coupling of the SM to
the MSSM is derived to order by comparing the
perturbative EFT to the fixed-order expression for the Higgs mass. The new
matching coefficient is made available through an updated version of the
program Himalaya. Numerical effects of the higher-order resummation are studied
using specific examples, and sources of theoretical uncertainty on this result
are discussed.Comment: 26 pages, 3 figures, matches version published in EPJ
Family Dependence in SU(3)_C X SU(3)_L X U(1)_X models
Using experimental results at the Z-pole and atomic parity violation, we
perform a chi-squared fit at 95% CL to obtain family-dependent bounds to Z_2
mass and Z-Z' mixing angle in the framework of SU(3)_C X SU(3)_L X U(1)_X
models. The allowed regions depend on the assignment of the quark families in
mass eigenstates into the three different families in weak eigenstates that
cancel anomaliesComment: 14 pages, 2 figures, LaTeX2e; added references, added equations with
electroweak corrections for section 4. Version to appear in Phys. Rev.
Quark mass hierarchy in 3-3-1 models
We study the mass spectrum of the quark sector in an special type I-like
model with gauge symmetry . By
considering couplings with scalar triplets at large () and small
() scales, we obtain specific zero-texture mass matrices for the
quarks which predict three massless quarks () and three massive quarks
() at the electroweak scale ( GeV). Taking into account mixing
couplings with three heavy quarks at large scales predicted by the model, the
three massless quarks obtain masses at small order that depends on the inverse
of the large scale. Thus, masses of the form
and can be obtained naturally from the gauge structure of
the model
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