7,084 research outputs found
Top 2014: Theory Summary
This write-up is the summary of the theoretical presentations at the Top 2014
Workshop held in Mandelieu France from September 29 to October 3, 2014.Comment: 7 page
Dark Matter from Unification of Color and Baryon Number
We analyze a recently proposed extension of the Standard Model based on the
SU(4) x SU(2)_L x U(1)_X gauge group, in which baryon number is interpreted as
the fourth color and dark matter emerges as a neutral partner of the ordinary
quarks under SU(4). We show that under well-motivated minimal flavor-violating
assumptions the particle spectrum contains a heavy dark matter candidate which
is dominantly the partner of the right-handed top quark. Assuming a standard
cosmology, the correct thermal relic density through freeze-out is obtained for
dark matter masses around 2 - 3 TeV. We examine the constraints and future
prospects for direct and indirect searches for dark matter. We also briefly
discuss the LHC phenomenology, which is rich in top quark signatures, and
investigate the prospects for discovery at a 100 TeV hadron collider.Comment: 6 pages, 5 figure
A Fat Higgs with a Fat Top
A new variant of the supersymmetric Fat Higgs model is presented in which the
MSSM Higgses as well as the top quark are composite. The underlying theory is
an s-confining SU(3) gauge theory with the MSSM gauge groups realized as gauged
sub-groups of the chiral flavor symmetries. This motivates the large Yukawas
necessary for the large top mass and SM-like Higgs of mass>>M_Z in a natural
way as the residual of the strong dynamics responsible for the composites. This
removes fine-tuning associated with these couplings present in the original Fat
Higgs and New Fat Higgs models, respectively.Comment: 17 pages, 4 figures, Latex2e, uses JHEP3.cls and youngtab.sty, new
references adde
A High Quality Composite Axion
The strong CP problem is a compelling motivation for physics beyond the
Standard Model. The most popular solutions invoke a global Peccei-Quinn
symmetry, but are challenged by quantum gravitational corrections which are
thought to be incompatible with global symmetries, arguing that realistic
theories contain additional structure. We explore a construction in which the
Peccei-Quinn symmetry is protected to arbitrary order by virtue of a
supersymmetric, confining
product gauge group, achieving for an model
with GeV. This construction leads to low energy
predictions such as a gauge symmetry, and for engineers a
naturally order ~TeV value for the parameter of the MSSM.Comment: 17 pages, 2 figures, 3 table
Extended MSSM Neutralinos as the Source of the PAMELA Positron Excess
We consider a scenario within the Minimal Supersymmetric Standard Model
extended by a singlet chiral superfield, in which neutralino dark matter
annihilates to light singlet-like Higgs bosons, which proceed to decay to
either electron-positron or muon-antimuon pairs. Unlike neutralino
annihilations in the MSSM, this model can provide a good fit to the PAMELA
cosmic ray positron fraction excess. Furthermore, the singlet-like scalar Higgs
can induce a large Sommerfeld enhancement and provide an annihilation rate
sufficient to accommodate the observed positron excess
Top Spin and Experimental Tests
We examine pair mass dependence near threshold as a means to measure the spin
of the top quark in hadron collisions, and we discuss the possibility that a
top squark signal could be hidden among the top events.Comment: 9 pages, RevTeX, 3 figures. Contribution to the Thinkshop on
Top-Quark Physics for the Tevatron Run II, Fermilab, October 16 - 18, 199
Collider Constraints on Dipole-Interacting Dark Matter
Dark matter which interacts through a magnetic or electric dipole moment is
an interesting possibility which may help to resolve the discrepancy between
the DAMA annual modulation signal and the null results of other searches. In
this article we examine relic density and collider constraints on such dark
matter, and find that for couplings needed to explain DAMA, the thermal relic
density is generically in the right ballpark to account for cosmological
measurements. Collider constraints are relevant for light WIMPs, but less
constraining that direct searches for masses above about 10 GeV.Comment: 11 pages, 2 figures, extended discussion, added references,
conclusion unchange
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