3,845 research outputs found
Light Axion within the Next-to-Minimal Supersymmetric Standard Model
We analyze the Higgs sector in the Next-to-Minimal Supersymmetric Standard
Model, emphasizing the possibility of a light CP-odd scalar (axion) in the
spectrum. We compute the coupling of the Standard-Model-like Higgs boson to a
pair of axions, and show that it can be large enough to modify the Higgs
branching fractions, with a significant impact on the Higgs searches. We
delineate the range of parameters relevant for this scenario, and also derive
analytic expressions for the scalar masses and couplings in two special cases -
a decoupling limit where all scalars other than the axion are heavier than the
Standard-Model-like Higgs boson, and the large tan beta limit.Comment: 28 pages, 6 figure
Dirichlet heat kernel for unimodal L\'evy processes
We estimate the heat kernel of the smooth open set for the isotropic unimodal
pure-jump L\'evy process with infinite L\'evy measure and weakly scaling
L\'evy-Kchintchine exponent.Comment: 38 page
Composite Vectorlike Fermions
We study a dynamical mechanism that generates a composite vectorlike fermion,
formed by the binding of an -tuplet of elementary chiral fermions to an
-tuplet of scalars. Deriving the properties of the composite fermion in the
large limit, we show that its mass is much smaller than the compositeness
scale when the binding coupling is near a critical value. We compute the
contact interactions involving four composite fermions, and find that their
coefficients scale as . Physics beyond the Standard Model may include
composite vectorlike fermions arising from this mechanism.Comment: 6 pages, 3 figure
Stochastic particle acceleration in flaring stars
The acceleration of electrons by the Fermi-Parker mechanisms in a quasistationary turbulent plasma of dimension l, mean magnetic field strength B, and mean number density n are considered. The electrons suffer radiative and ionization losses and have a scattering mean free path that increases linearly with their momentum. Analytic solutions for the steady-state electron energy spectra are presented. The spectra are characterized by an exponential cutoff above a given momentum determined by the synchrontron or the confinement time, depending on the physical characteristics of the accelerating region
A comparison of the Benjamini-Hochberg procedure with some Bayesian rules for multiple testing
In the spirit of modeling inference for microarrays as multiple testing for
sparse mixtures, we present a similar approach to a simplified version of
quantitative trait loci (QTL) mapping. Unlike in case of microarrays, where the
number of tests usually reaches tens of thousands, the number of tests
performed in scans for QTL usually does not exceed several hundreds. However,
in typical cases, the sparsity of significant alternatives for QTL mapping
is in the same range as for microarrays. For methodological interest, as well
as some related applications, we also consider non-sparse mixtures. Using
simulations as well as theoretical observations we study false discovery rate
(FDR), power and misclassification probability for the Benjamini-Hochberg (BH)
procedure and its modifications, as well as for various parametric and
nonparametric Bayes and Parametric Empirical Bayes procedures. Our results
confirm the observation of Genovese and Wasserman (2002) that for small p the
misclassification error of BH is close to optimal in the sense of attaining the
Bayes oracle. This property is shared by some of the considered Bayes testing
rules, which in general perform better than BH for large or moderate 's.Comment: Published in at http://dx.doi.org/10.1214/193940307000000158 the IMS
Collections (http://www.imstat.org/publications/imscollections.htm) by the
Institute of Mathematical Statistics (http://www.imstat.org
Three-dimensional magnetostatic models of the large-scale corona
A special class of magnetostatic equilibria is described, which are mathematically simple and yet sufficiently versatile so as to fit any arbitrary normal magnetic flux prescribed at the photosphere. With these solutions, the corona can be modeled with precisely the same mathematically simple procedure as has previously been done with potential fields. The magnetostatic model predicts, in addition to the coronal magnetic field, the three dimensional coronal density which can be compared with coronagraph observations
One-dimensional quasi-relativistic particle in the box
Two-term Weyl-type asymptotic law for the eigenvalues of one-dimensional
quasi-relativistic Hamiltonian (-h^2 c^2 d^2/dx^2 + m^2 c^4)^(1/2) + V_well(x)
(the Klein-Gordon square-root operator with electrostatic potential) with the
infinite square well potential V_well(x) is given: the n-th eigenvalue is equal
to (n pi/2 - pi/8) h c/a + O(1/n), where 2a is the width of the potential well.
Simplicity of eigenvalues is proved. Some L^2 and L^infinity properties of
eigenfunctions are also studied. Eigenvalues represent energies of a `massive
particle in the box' quasi-relativistic model.Comment: 40 pages, 4 figures; minor correction
Electroweak symmetry breaking by extra dimensions
Electroweak symmetry breaking may be naturally induced by the observed quark
and gauge fields in extra dimensions without a fundamental Higgs field. We show
that a composite Higgs doublet can arise as a bound state of and a
linear combination of the Kaluza-Klein states of , due to QCD in extra
dimensions. The top quark mass depends on the number of active
Kaluza-Klein modes, and is consistent with the experimental value.Comment: 4 pages, LaTeX, talk presented at PASCOS99, Lake Tahoe, Californi
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