18,762 research outputs found
Superconducting Vortices induced Periodic Magnetoresistance Oscillations in Single Crystal Au Nanowires
We show in this paper that it is possible to induce superconducting vortices
in a gold nanowire connected to superconducting electrodes. The gold nanowire
acquires superconductivity by the proximity effect. The differential
magnetoresistance of the nanowire beyond a critical magnetic field shows
uniform oscillations with increasing field with a period of \phi0/(2\pir^2)
(\phi0 = h/2e is the superconducting flux quantum, r = 35 nm is the radius of
the nanowire). We demonstrate that these periodic oscillations are the
signatures of the sequential generation and moving of vortices across the gold
nanowire
LHC Signatures of Two-Higgs-Doublets with Fourth Family
On-going Higgs searches in the light mass window are of vital importance for
testing the Higgs mechanism and probing new physics beyond the standard model
(SM). The latest ATLAS and CMS searches for the SM Higgs boson at the LHC
(7TeV) found some intriguing excesses of events in the \gamma\gamma/VV^*
channels (V=Z,W) around the mass-range of 124-126 GeV. We explore a possible
explanation of the \gamma\gamma and VV^* signals from the light CP-odd Higgs
A^0 or CP-even Higgs h^0 from the general two-Higgs-doublet model with
fourth-family fermions. We demonstrate that by including invisible decays of
the Higgs boson A^0 or h^0 to fourth-family neutrinos, the predicted
\gamma\gamma and VV^* signals can explain the observed new signatures at the
LHC, and will be further probed by the forthcoming LHC runs in 2012.Comment: 22pp, 10 Figs, JHEP published version, references adde
Probing Gravitational Dark Matter
So far all evidences of dark matter (DM) come from astrophysical and
cosmological observations, due to gravitational interactions of the DM. It is
possible that the true DM particle in the universe joins gravitational
interactions only, but nothing else. Such a Gravitational DM (GDM) acts as a
weakly interacting massive particle (WIMP), which is conceptually simple and
attractive. In this work, we explore this direction by constructing the
simplest scalar GDM particle . It is a odd singlet under the
standard model (SM) gauge group, and naturally joins the unique dimension-4
interaction with Ricci curvature, , where is the
dimensionless nonminimal coupling. We demonstrate that this gravitational
interaction , together with Higgs-curvature nonminimal
coupling term , induces effective couplings between
and SM fields which can account for the observed DM thermal relic
abundance. We analyze the annihilation cross sections of GDM particles and
derive the viable parameter space for realizing the DM thermal relic density.
We further study the direct/indirect detections and the collider signatures of
such a scalar GDM. These turn out to be highly predictive and testable.Comment: 33pp, JCAP Final Version. Only minor rewordings, references adde
Asymptotically Safe Higgs Inflation
We construct a new inflation model in which the standard model Higgs boson
couples minimally to gravity and acts as the inflaton. Our construction of
Higgs inflation incorporates the standard model with Einstein gravity which
exhibits asymptotic safety in the ultraviolet region. The slow roll condition
is satisfied at large field value due to the asymptotically safe behavior of
Higgs self-coupling at high energies. We find that this minimal construction is
highly predictive, and is consistent with both cosmological observations and
collider experiments.Comment: 16pp, to match JCAP Final Version, only minor refinements, references
adde
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