6,407 research outputs found
On decays of Z' into unparticle stuff
We study the decay of a Z' - boson into U -unparticle and a photon. The
extended Landau-Yang theorem is used. The clear photon signal would make the
decay Z' \rightarrow \gamma U as an additional contribution mode for study of
unparticle physics.Comment: 11 pages, 3 figures, paper accepted for publication by Advances in
High Energy Physics journa
Dark matter component decaying after recombination: lensing constraints with Planck data
It has been recently suggested~\cite{Berezhiani:2015yta} that emerging
tension between cosmological parameter values derived in high-redshift (CMB
anisotropy) and low-redshift (cluster counts, Hubble constant) measurements can
be reconciled in a model which contains subdominant fraction of dark matter
decaying after recombination. We check the model against the CMB Planck data.
We find that lensing of the CMB anisotropies by the large-scale structure gives
strong extra constraints on this model, limiting the fraction as at
2\, confidence level. However, investigating the combined data set of
CMB and conflicting low- measurements, we obtain that the model with
\% exhibits better fit (by 1.5-3\, depending on the
lensing priors) compared to that of the concordance CDM cosmological
model.Comment: 5 pages, 4 figures; v2: journal version, pages++, figures+
Hidden supersymmetry and Berezin quantization of N=2, D=3 spinning superparticles
The first quantized theory of N=2, D=3 massive superparticles with arbitrary
fixed central charge and (half)integer or fractional superspin is constructed.
The quantum states are realized on the fields carrying a finite dimensional, or
a unitary infinite dimensional representation of the supergroups OSp(2|2) or
SU(1,1|2). The construction originates from quantization of a classical model
of the superparticle we suggest. The physical phase space of the classical
superparticle is embedded in a symplectic superspace
, where the inner K\"ahler supermanifold
provides
the particle with superspin degrees of freedom. We find the relationship
between Hamiltonian generators of the global Poincar\'e supersymmetry and the
``internal'' SU(1,1|2) one. Quantization of the superparticle combines the
Berezin quantization on and the conventional Dirac quantization
with respect to space-time degrees of freedom. Surprisingly, to retain the
supersymmetry, quantum corrections are required for the classical N=2
supercharges as compared to the conventional Berezin method. These corrections
are derived and the Berezin correspondence principle for underlying
their origin is verified. The model admits a smooth contraction to the N=1
supersymmetry in the BPS limit.Comment: 43 pages, LaTeX Version 2.0
Evidence for a connection between the gamma-ray and the highest energy cosmic-ray emissions by BL Lacertae objects
A set of potentially gamma-ray--loud BL Lac objects is selected by
intersecting the EGRET and BL Lac catalogs. Of the resulting 14 objects, eight
are found to correlate with arrival directions of ultra--high-energy cosmic
rays (UHECRs), with significance of the order of 5 sigma. This suggests that
gamma-ray emission can be used as a distinctive feature of those BL Lac objects
that are capable of producing UHECR.Comment: 11 pages, 1 figure, version published in APJ Letter
Hidden nonlinear supersymmetries in pure parabosonic systems
The existence of intimate relation between generalized statistics and
supersymmetry is established by observation of hidden supersymmetric structure
in pure parabosonic systems. This structure is characterized generally by a
nonlinear superalgebra. The nonlinear supersymmetry of parabosonic systems may
be realized, in turn, by modifying appropriately the usual supersymmetric
quantum mechanics. The relation of nonlinear parabosonic supersymmetry to the
Calogero-like models with exchange interaction and to the spin chain models
with inverse-square interaction is pointed out.Comment: 20 pages, one reference corrected, to appear in Int. J. Mod. Phys.
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