1,412 research outputs found
The Marital/Separate Property Distinction in the District of Columbia
This article is part of Developments of the Law in the District of Columbia
The Marital/Separate Property Distinction in the District of Columbia
This article is part of Developments of the Law in the District of Columbia
Low lying S=-1 excited baryons and chiral symmetry
The s-wave meson-baryon interaction in the sector is studied by
means of coupled-channels, using the lowest-order chiral Lagrangian and the N/D
method to implement unitarity. The loops are regularized using dimensional
renormalization. In addition to the previously studied ,
employing this chiral approach leads to the dynamical generation of two more
s-wave hyperon resonances, the and states. We
make comparisons with experimental data and look for poles in the complex plane
obtaining the couplings of the resonances to the different final states. This
allows us to identify the and the resonances
with and quasibound states, respectively.Comment: 12 pages, 2 figures, revised version to appear in Phys. Lett. B,
errata corrected: modulus of coupling contants is modulus square
Lattice Matrix Elements and CP Violation in B and K Physics: Status and Outlook
Status of lattice calculations of hadron matrix elements along with CP
violation in B and in K systems is reviewed. Lattice has provided useful input
which, in conjunction with experimenatl data, leads to the conclusion that
CP-odd phase in the CKM matrix plays the dominant role in the observed
asymmetry in . It is now quite likely that any beyond the SM,
CP-odd, phase will cause only small deviations in B-physics. Search for the
effects of the new phase(s) will consequently require very large data samples
as well as very precise theoretical predictions. Clean determination of {\it
all} the angles of the unitarity triangle therefore becomes essential. In this
regard processes play a unique role. Regarding K-decays,
remarkable progress made by theory with regard to maintenance of chiral
symmetry on the lattice is briefly discussed. First application already provide
quantitaive information on and the rule. The enhancement
in appears to arise solely from tree operators, esp. ; penguin
contribution to appears to be very small. However, improved
calculations are necessary for \epsilon^'/epsilon as there the contributions
of QCD penguins and electroweak penguins largely seem to cancel. There are good
reasons, though, to believe that these cancellations will not survive
improvements that are now underway. Importance of determining the unitarity
triangle purely from K-decays is also emphasized.Comment: Invited talk at the 9th International Symposium on Particles, Strings
and Cosmology (PASCOS 03), Mumbai (Bombay) India,3-8 Jan 200
What can we learn from a measurement of sin(2 beta + gamma)?
The constraints on the value of the CKM phase gamma that may be achieved by
prospective measurements of sin(2 beta) and sin(2 beta + gamma) are discussed.
Significant constraints require quite small errors, and may depend on
assumptions about strong phases. The measurement of sin(2 beta + gamma)
combined with other experiments could provide valuable limits on new physics in
Bd-Bdbar mixing.Comment: 10 pages, 7 figures, RevTex 4, uses amsmath and graphic
Possible evidence for the breakdown of the CKM-paradigm of CP-violation
Using primarily experimental inputs for S(B -> psi Ks), Delta M_Bs, Delta
M_Bd, BR(B -> tau nu) and epsilon_K along with necessary inputs from the
lattice, we find that the measured value of sin(2 beta) is smaller than
expectations of the Standard Model by as much as 3.3 sigma, and also that the
measured value of the BR(B -> tau nu) seems to be less than the predicted value
by about 2.8 sigma. However, through a critical study we show that most likely
the dominant source of these deviations is in B_d(s) mixings and in sin(2 beta)
and less so in B -> tau nu, and also that the bulk of the problem persists even
if input from epsilon_K is not used. The fact that kaon mixing and epsilon_K
are not the dominant source of the deviation from the Standard Model has the
very important consequence that model independent considerations imply that the
scale of the relevant new CP-violating physics is below O(2 TeV), thus
suggesting that direct signals of the new particle(s) may well be accessible in
collider experiments at the LHC and perhaps even at the Tevatron.Comment: 6 pages, 8 figures. Added another fit and some more discussion
showing that BR(B->tau nu) comes out in good agreement with predictions of
the SM if the measured value of sin2beta is not used as an input. References
adde
Parity-Violating Excitation of the \Delta(1232): Hadron Structure and New Physics
We consider prospects for studying the parity-violating (PV) electroweak
excitation of the \Delta(1232) resonance with polarized electron scattering.
Given present knowledge of Standard Model parameters, such PV experiments could
allow a determination of the N -> \Delta electroweak helicity amplitudes. We
discuss the experimental feasibility and theoretical interpretability of such a
determination as well as the prospective implications for hadron structure
theory. We also analyze the extent to which a PV N -> \Delta measurement could
constrain various extensions of the Standard Model.Comment: 43 pages, RevTex, 8 PS figures, uses epsf.sty, rotate.sty, version to
appear in Nucl. Phys. A, main points emphasized, some typos correcte
Implications of the Top Quark Mass Measurement for the CKM Parameters, and CP Asymmetries
Motivated by the recent determination of the top quark mass by the CDF
collaboration, \mt =174 \pm 10 ^{+13}_{-12} GeV, we review and update the
constraints on the parameters of the quark flavour mixing matrix in
the standard model. In performing our fits, we use inputs from the measurements
of the following quantities: (i) \abseps, the CP-violating parameter in
decays, (ii) \delmd, the mass difference due to the \bdbdbar\ mixing, (iii)
the matrix elements \absvcb and \absvub, and (iv) -hadron lifetimes. We
find that the allowed region of the unitarity triangle is very large, mostly
due to theoretical uncertainties. (This emphasizes the importance of
measurements of CP-violating rate asymmetries in the system.) Nevertheless,
the present data do somewhat restrict the allowed values of the coupling
constant product and the renormalization-scale
invariant bag constant . With the updated CKM matrix we present the
currently-allowed range of the ratio , as well as
the standard model predictions for the \bsbsbar\ mixing parameter \xs and the
quantities , and , which characterize
the CP-asymmetries in -decays. The ALEPH collaboration has recently reported
a significant improvement on the lower limit on the \bs-\bsb mass
difference, (95\% C.L.). This has interesting
consequences for the CKM parameters which are also worked out.
NOTE: this is a revised and updated version of our previous paper.Comment: LaTeX, 27 pages, 16 uuencoded figures (enclosed), CERN-TH.7398/94,
UdeM-GPP-TH-94-0
Towards a Model-Independent Analysis of Rare Decays
Motivated by the experimental accessibility of rare decays in the ongoing
and planned experiments, we propose to undertake a model-independent analysis
of the inclusive decay rates and distributions in the processes \bgamaxs~ and
\Bsell ~( or ). We show how measurements of the decay rates and
distributions in these processes would allow us to extract the magnitude and
sign of the dominant Wilson coefficients of the magnetic moment operator \mb
\bar{s}_L \sigma_{\mu \nu} b_R F^{\mu \nu } and the four-fermion operators
and . Non-standard-model
effects could thus manifest themselves at low energy in rare decays through
the Wilson coefficient having values distinctly different from their
standard-model counterparts. We illustrate this possibility using the examples
of the two-doublet Higgs models and the minimal supersymmetric models. The
dilepton invariant mass spectrum and the forward-backward asymmetry of
in the centre-of-mass system of the dilepton pair in the decay \Bsell ~are also
worked out for the standard model and some representative solutions for the
other two models.Comment: LaTeX, 36 pages, 11 figures appended after \end{document} as
uu-encoded and compressed .eps files, uses epsf, CERN-TH.7346/9
The effects of caffeinated and decaffeinated coffee on sex hormone-binding globulin and endogenous sex hormone levels: A randomized controlled trial
10.1186/1475-2891-11-86Nutrition Journal111
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