175 research outputs found
The encyclopedia of actuarial science
We give a short historical survey on why and how the Encyclopedia has emerged. We consider both the editorial and the managerial side of the project. We indicate some of the special features of the work
Radiative Mechanism to Light Fermion Masses in the MSSM
In a previous work we have showed that the Symmetry,
imply that the light fermions, the electron and the quarks, and , get
their masses only at one loop level. Here, we considere the more general
hypothesis for flavour mixing in the sfermion sector in the MSSM. Then, we
present our results to the masses of these light fermions and as a final result
we can explain why the quark is heavier than the quarks. This
mechanism is in agrement with the experimental constraint on the sfermion's
masses values.Comment: 22 pages, 8 figures, TeX mistakes corrected, accepted for publication
in JHE
K* nucleon hyperon form factors and nucleon strangeness
A crucial input for recent meson hyperon cloud model estimates of the nucleon
matrix element of the strangeness current are the nucleon-hyperon-K* (NYK*)
form factors which regularize some of the arising loops. Prompted by new and
forthcoming information on these form factors from hyperon-nucleon potential
models, we analyze the dependence of the loop model results for the
strange-quark observables on the NYK* form factors and couplings. We find, in
particular, that the now generally favored soft N-Lambda-K* form factors can
reduce the magnitude of the K* contributions in such models by more than an
order of magnitude, compared to previous results with hard form factors. We
also discuss some general implications of our results for hadronic loop models.Comment: 9 pages, 8 figures, new co-author, discussion extended to the
momentum dependence of the strange vector form factor
Super-conservative interpretation of muon g-2 results applied to supersymmetry
The recent developments in theory and experiment related to the anomalous
magnetic moment of the muon are applied to supersymmetry. We follow a very
cautious course, demanding that the supersymmetric contributions fit within
five standard deviations of the difference between experiment and the standard
model prediction. Arbitrarily small supersymmetric contributions are then
allowed, so no upper bounds on superpartner masses result. Nevertheless,
non-trivial exclusions are found. We characterize the substantial region of
parameter space ruled out by this analysis that has not been probed by any
previous experiment. We also discuss some implications of the results for
forthcoming collider experiments.Comment: 10 pages, latex, 3 fig
Reevaluation of the role of nuclear uncertainties in experiments on atomic parity violation with isotopic chains
In light of new data on neutron distributions from experiments with
antiprotonic atoms [ Trzcinska {\it et al.}, Phys. Rev. Lett. 87, 082501
(2001)], we reexamine the role of nuclear-structure uncertainties in the
interpretation of measurements of parity violation in atoms using chains of
isotopes of the same element. With these new nuclear data, we find an
improvement in the sensitivity of isotopic chain measurements to ``new
physics'' beyond the standard model. We compare possible constraints on ``new
physics'' with the most accurate to date single-isotope probe of parity
violation in the Cs atom. We conclude that presently isotopic chain experiments
employing atoms with nuclear charges Z < 50 may result in more accurate tests
of the weak interaction.Comment: 6 pages, 1 fig., submitted to Phys. Rev.
Hadronic Parity Violation and Inelastic Electron-Deuteron Scattering
We compute contributions to the parity-violating (PV) inelastic
electron-deuteron scattering asymmetry arising from hadronic PV. While hadronic
PV effects can be relatively important in PV threshold electro- disintegration,
we find that they are highly suppressed at quasielastic kinematics. The
interpretation of the PV quasielastic asymmetry is, thus, largely unaffected by
hadronic PV.Comment: 27 pages, 13 figures, uses REVTeX and BibTe
Supergauge interactions and electroweak baryogenesis
We present a complete treatment of the diffusion processes for supersymmetric
electroweak baryogenesis that characterizes transport dynamics ahead of the
phase transition bubble wall within the symmetric phase. In particular, we
generalize existing approaches to distinguish between chemical potentials of
particles and their superpartners. This allows us to test the assumption of
superequilibrium (equal chemical potentials for particles and sparticles) that
has usually been made in earlier studies. We show that in the Minimal
Supersymmetric Standard Model, superequilibrium is generically maintained --
even in the absence of fast supergauge interactions -- due to the presence of
Yukawa interactions. We provide both analytic arguments as well as illustrative
numerical examples. We also extend the latter to regions where analytical
approximations are not available since down-type Yukawa couplings or supergauge
interactions only incompletely equilibrate. We further comment on cases of
broken superequilibrium wherein a heavy superpartner decouples from the
electroweak plasma, causing a kinematic bottleneck in the chain of
equilibrating reactions. Such situations may be relevant for baryogenesis
within extensions of the MSSM. We also provide a compendium of inputs required
to characterize the symmetric phase transport dynamics.Comment: 49 pages, 9 figure
The Off-diagonal Goldberger-Treiman Relation and Its Discrepancy
We study the off-diagonal Goldberger-Treiman relation (ODGTR) and its
discrepancy (ODGTD) in the N, Delta, pi sector through O(p^2) using heavy
baryon chiral perturbation theory. To this order, the ODGTD and axial vector N
to Delta transition radius are determined solely by low energy constants. Loop
corrections appear at O(p^4). For low-energy constants of natural size, the
ODGTD would represent a ~ 2% correction to the ODGTR. We discuss the
implications of the ODGTR and ODGTD for lattice and quark model calculations of
the transition form factors and for parity-violating electroexcitation of the
Delta.Comment: 11 pages, 1 eps figur
Implications of the Muon Anomalous Magnetic Moment for Supersymmetry
We re-examine the bounds on supersymmetric particle masses in light of the
E821 data on the muon anomalous magnetic moment. We confirm, extend and
supersede previous bounds. In particular we find (at one sigma) no lower limit
on tan(beta) or upper limit on the chargino mass implied by the data at
present, but at least 4 sparticles must be lighter than 700 to 820 GeV and at
least one sparticle must be lighter than 345 to 440 GeV. However, the E821
central value bounds tan(beta) > 4.7 and the lighter chargino mass by 690 GeV.
For tan(beta) < 10, the data indicates a high probability for direct discovery
of SUSY at Run II or III of the Tevatron.Comment: 20 pages LaTeX, 14 figures; references adde
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