1,590 research outputs found
Sfermion Pair Production at Colliders
We discuss pair production of stops, sbottoms, staus and tau--sneutrinos at a
collider. We present the formulae for the production cross
sections and perform a detailed numerical analysis within the Minimal
Supersymmetric Standard Model. In particular, we consider sfermion production
near and .Comment: 21 pages, Latex, uses Revtex (included), 8 figures (included as
PS-files
Supernova matter at subnuclear densities as a resonant Fermi gas: Enhancement of neutrino rates
At low energies nucleon-nucleon interactions are resonant and therefore
supernova matter at subnuclear densities has many similarities to atomic gases
with interactions dominated by a Feshbach resonance. We calculate the rates of
neutrino processes involving nucleon-nucleon collisions and show that these are
enhanced in mixtures of neutrons and protons at subnuclear densities due to the
large scattering lengths. As a result, the rate for neutrino pair
bremsstrahlung and absorption is significantly larger below 10^{13} g cm^{-3}
compared to rates used in supernova simulations.Comment: 5 pages, 4 figures, published version, NORDITA-2014-2
Duality for pathwise superhedging in continuous time
We provide a model-free pricing-hedging duality in continuous time. For a
frictionless market consisting of risky assets with continuous price
trajectories, we show that the purely analytic problem of finding the minimal
superhedging price of a path dependent European option has the same value as
the purely probabilistic problem of finding the supremum of the expectations of
the option over all martingale measures. The superhedging problem is formulated
with simple trading strategies, the claim is the limit inferior of continuous
functions, which allows for upper and lower semi-continuous claims, and
superhedging is required in the pathwise sense on a -compact sample
space of price trajectories. If the sample space is stable under stopping, the
probabilistic problem reduces to finding the supremum over all martingale
measures with compact support. As an application of the general results we
deduce dualities for Vovk's outer measure and semi-static superhedging with
finitely many securities
Triple product correlations in top squark decays
We propose several T-odd asymmetries in the decay chains of the top squarks
and and , for . We
calculate the asymmetries within the Minimal Supersymmetric Standard Model with
complex parameters , and . We give the analytic formulae for
the decay distributions. We present numerical results for the asymmetries and
estimate the event rates necessary to observe them. The largest T-odd asymmetry
can be as large as 40%.Comment: 26 pages, 5 figures; misprints corrected; reference adde
SUSY-QCD corrections to stop and sbottom decays into Higgs bosons
We calculate the order(\alpha_s) SUSY-QCD corrections to the widths of stop
and sbottom decays into Higgs bosons within the Minimal Supersymmetric Standard
Model. We give the complete analytical formulae paying particular attention to
the on-shell renormalization of the soft SUSY-breaking parameters. We also
perform a detailed numerical analysis of both stop and sbottom decays into all
Higgs bosons h^0, H^0, A^0, and H^\pm. We find that the SUSY-QCD corrections
are significant, mostly negative and of the order of a few ten percent.Comment: revised version, one figure and a few comments adde
Neutralino Phenomenology at LEP2 in Supersymmetry with Bilinear Breaking of R-parity
We discuss the phenomenology of the lightest neutralino in models where an
effective bilinear term in the superpotential parametrizes the explicit
breaking of R-parity. We consider supergravity scenarios where the lightest
supersymmetric particle (LSP) is the lightest neutralino and which can be
explored at LEP2. We present a detailed study of the LSP decay properties and
general features of the corresponding signals expected at LEP2. We also
contrast our model with gauge mediated supersymmetry breaking.Comment: 21 pages, Latex, uses axodraw.sty (included), 13 figures included as
ps- and eps-files, figures slightly changed after bug-fixing, comparison with
GMSB and a few references added, version to appear in NP
CP asymmetries in the supersymmetric trilepton signal at the LHC
In the CP-violating Minimal Supersymmetric Standard Model, we study the
production of a neutralino-chargino pair at the LHC. For their decays into
three leptons, we analyze CP asymmetries which are sensitive to the CP phases
of the neutralino and chargino sector. We present analytical formulas for the
entire production and decay process, and identify the CP-violating
contributions in the spin correlation terms. This allows us to define the
optimal CP asymmetries. We present a detailed numerical analysis of the cross
sections, branching ratios, and the CP observables. For light neutralinos,
charginos, and squarks, the asymmetries can reach several 10%. We estimate the
discovery potential for the LHC to observe CP violation in the trilepton
channel.Comment: 39 pages, 8 figures, version to appear in EPJC, discussion(s) added,
typo in (D.79), (D.118) corrected, new Fig. 7; The European Physical Journal
C, Volume 72, Issue 3, 201
Supersymmetric Electroweak Corrections to Heavier Top Squark Decay into Lighter Top Squark and Neutral Higgs Boson
We calculate the Yukawa corrections of order , and
to the widths of the decays in the Minimal Supersymmetric Standard
Model, and perform a detailed numerical analysis. We also compare the results
with the ones presented in an earlier literature, where the SUSY-QCD corrections to the same three decay processes have
been calculated.
Our numerical results show that for the decays , , the Yukawa corrections are
significant in most of the parameter range, which can reach a few ten percent,
and for the decay , the Yukawa corrections are
relatively smaller, which are only a few percent. The numerical calculations
also show that using the running quark masses and the running trilinear
coupling , which include the QCD, SUSY-QCD, SUSY-Electroweak effects and
resume all high order ()-enhanced effects, can vastly improve the
convergence of the perturbation expansion. We also discuss the effects of the
running of the higgsino mass parameter on the corrections, and find that
they are significant, too, especially for large .Comment: 37 pages, 19 eps figure
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