651 research outputs found
Large Hadroproduction of as a Probe of Gluon Distribution inside Proton
The transverse momentum distribution of single vector boson production at
hadron colliders provides useful ways of testing the Standard Model and
searching new physics beyond the Standard Model. We study large
hadroproduction of -boson as a probe of gluon distributions inside proton.
We investigate how to get initial gluon-involving contributions, or how to
subtract quark-quark (or -antiquark) contributions from total cross section. We
also investigated the simultaneous measurement of the rapidity and the
transverse momentum of the produced boson, to obtain momentum fractions of
initial partons. And we extracted relevant uncertainties involving in
experimental and theoretical analyses. This large hadroproduction of
can be used as constraints on analyses of global parton (gluon and quarks)
distribution functions inside proton.Comment: (a) 13 pages(LaTeX) + 1 figure ps file(3 pages):compressed, uuencoded
(b) accepted by Phys.Lett.B. (c) some figures are combined and one is
omitted. (d) conclusion part is included into abstrac
Interactions between Grape Maturity Indices and Quality for Pinotage and Cabernet Sauvignon Wines from Four Localities
Three grape maturity indices viz. degrees Balling (OB), OB total titratable acid (TT A) ratio and the OB.pH product of musts were compared regarding their ability to predict optimum quality for Cabernet Sauvignon and Pinotage wines. Comprehensive analytical data from 128 musts and corresponding wines for the 1979 and 1980 vintages from the Stellenbosch, Durbanville, Lutzville and Robertson areas were subjected to principal component analysis using variables and variable ratios selected by correlation to quality weighting. The results indicated that 0B alone could not perform the function of a grape maturity index for predicting optimum quality. In the case of the OB/TT A index, the range wherein maximum wine quality occurred was too wide tobe of practical value in this instance. The 0B.pH index gave a narrower optimum range, and in contrast to the two other indices gave similar results for both cultivars
Extended double seesaw model for neutrino mass spectrum and low scale leptogenesis
We consider a variant of seesaw mechanism by introducing extra singlet
neutrinos, with which we show how the low scale leptogenesis is realized
without imposing the tiny mass splitting between two heavy Majorana neutrinos
required in the resonant leptogenesis. Thus, we can avoid the so-called
gravitino problem when our scenario is supersymmetrized. We show that an
introduction of the new singlet fermion leads to a new contribution which can
enhance the lepton asymmetry for certain range of parameter space. We also
examine how both the light neutrino mass spectrum and relatively light sterile
neutrinos of order a few 100 MeV can be achieved without being in conflict with
the constraints on the mixing between the active and sterile neutrinos.Comment: RevTex 12 pages, 1 figure, title changed, typos corrected, numerical
results improved, to appear in Phys. Lett.
SUSY-QCD Effect on Top-Charm Associated Production at Linear Collider
We evaluate the contribution of SUSY-QCD to top-charm associated production
at next generation linear colliders. Our results show that the production cross
section of the process could be as large as 0.1
fb, which is larger than the prediction of the SM by a factor of .Comment: version to appear in PR
Virtual SUSY Threshold Effects and CDF large Anomaly
Recent CDF data of the inclusive jet cross section shows threshold-like
structured deviation, around transverse momentum
GeV. If this data is real, not just some statistical fluctuation, is it
possible to interpret the anomaly in terms of virtual SUSY effects? The purpose
of this note is to address this question. However, we find that virtual SUSY
loop interference effects [near the threshold] are too small to explain the CDF
data. Our main conclusion seems to be on the right track if we assume that the
recent global analysis of improved parton distributions by Lai et al. is
correct. PACS number(s): 14.65.Ha, 12.38.Bx, 12.60.Jv, 13.85.-tComment: 10 pages, RevTex, 1 Tex file and 5-page postscript together, To
appear in Phys.Lett.
Virtual Effects of Split SUSY in Higgs Productions at Linear Colliders
In split supersymmetry the gauginos and higgsinos are the only supersymmetric
particles possibly accessible at foreseeable colliders like the CERN Large
Hadron Collider (LHC) and the International Linear Collider (ILC). In order to
account for the cosmic dark matter measured by WMAP, these gauginos and
higgsinos are stringently constrained and could be explored at the colliders
through their direct productions and/or virtual effects in some processes. The
clean environment and high luminosity of the ILC render the virtual effects of
percent level meaningful in unraveling the new physics effects. In this work we
assume split supersymmetry and calculate the virtual effects of the
WMAP-allowed gauginos and higgsinos in Higgs productions e+e- -> Z h and e+e-
-> \nu_e \bar_\nu_e h through WW fusion at the ILC. We find that the production
cross section of e+e- -> Zh can be altered by a few percent in some part of the
WMAP-allowed parameter space, while the correction to the WW-fusion process
e+e- -> \nu_e \bar_\nu_e h is below 1%. Such virtual effects are correlated
with the cross sections of chargino pair productions and can offer
complementary information in probing split supersymmetry at the colliders.Comment: more discussions added (7 pages, 10 figs
Dietary quality and patterns and non-communicable disease risk of an Indian community in KwaZulu-Natal, South Africa
BACKGROUND : Limited data exist on the South African Indian diet despite their high prevalence of non-communicable
diseases. This study attempted to determine the dietary quality and patterns of an Indian population in KwaZulu-Natal
with reference to the high prevalence of non-communicable disease
METHODS : Two-hundred-and-fifty apparently healthy Indians, aged 35–55 years participated in a cross-sectional study
where diet was assessed using a validated quantitative food frequency questionnaire. Mean intakes were compared to
the World Health Organization goals. Dietary quality was determined by index construction and dietary patterns by factor
analysis.
RESULTS : The mean daily percentage of energy (%E) from n-3 fatty acids (0.24 %E), dietary fibre (18.4 g/day) and fruit
and vegetable intakes (229.4 g/day) were below the World Health Organization goals. Total fat (36.1 %E),
polyunsaturated fatty acids (11.8 %E), n-6 fatty acids (11 %E) and free sugars (12.5 %E) exceeded the goals. The means
for the deficient index reflected a moderate diet quality whereas, the excess index reflected good diet quality. The
Pearson partial correlation coefficients between the deficient index and risk markers were weak whilst, the excess index
was inversely correlated with waist circumference for the whole sample. Two factors were identified, based on the
percentage of fat that contributed to each food group: factor 1 (meat and fish versus legume and cereal pattern),
which accounted for added fat through food preparation; and Factor 2 (nuts and seeds versus sugars and visible fat
pattern), which accounted for obvious fat. The medians for waist circumference, blood glucose, cholesterol and
triglyceride levels showed significant decreasing trends for factor 1 (p < 0.05). The medians for blood glucose and
cholesterol showed significant decreasing trends for factor 2 (p < 0.01).
CONCLUSION : A shortfall of fruit and vegetable, fibre and n-3 fatty acid intake in the diet is highlighted. When assessing
the diet quality and patterns, guidance on the prudent use of added fats may lead to a healthier lifestyle reducing the
prevalence of non-communicable diseases.Grants from the South African Medical Research Council,
National Research Foundation; Thuthuka and North-West University.am201
Flavor Democracy in Standard Models at High Energies
It is possible that the standard model (SM) is replaced around some
transition energy \E_{tr} by a new, possibly Higgsless, ``flavor gauge
theory'' such that the Yukawa (running) parameters of SM at E \sim \E_{tr}
show up an (approximate) flavor democracy (FD). We investigate the latter
possibility by studying the renormalization group equations for the Yukawa
couplings of SM with one and two Higgs doublets, by evolving them from given
physical values at low energies () to \E_{tr} ( \sim
\E_{pole}) and comparing the resulting fermion masses and CKM matrix elements
at E \simeq \E_{tr} for various and ratios of vacuum
expectation values. We find that the minimal SM and the closely related SM with
two Higgs doublets (type I) show increasing deviation from FD when energy is
increased, but that SM with two Higgs doublets (type II) clearly tends to FD
with increasing energy - in both the quark and the leptonic sector (q-q and l-l
FD). Furthermore, we find within the type II model that, for \E_{pole} \ll
\E_{Planck}, can be less than in most cases of chosen
. Under the assumption that also the corresponding Yukawa couplings in
the quark and the leptonic sector at E \simeq \E_{tr} are equal (l-q FD), we
derive estimates of bounds on masses of top quark and tau-neutrino, which are
compatible with experimental bounds.Comment: 23 pages (7 Figs. available on request), standard LATEX, preprint
DO-TH 93-08, SNUTP 93-12, YUMS 93-0
Supersymmetric CP Violation in in Minimal Supergravity Model
Direct CP asymmetries and the CP violating normal polarization of lepton in
inclusive decay B \to X_s l^+ l^- are investigated in minimal supergravity
model with CP violating phases. The contributions coming from exchanging
neutral Higgs bosons are included. It is shown that the direct CP violation in
branching ratio, A_{CP}^1, is of {\cal{O}}(10^{-3}) for l=e, \mu, \tau. The CP
violating normal polarization for l=\mu can reach 0.5 percent when tan\beta is
large (say, 36). For l=\tau and in the case of large \tan\beta, the direct CP
violation in backward-forward asymmetry, A_{CP}^2, can reach one percent, the
normal polarization of \tau can be as large as a few percent, and both are
sensitive to the two CP violating phases, \phi_\mu and \phi_{A_0}, and
consequently it could be possible to observe them (in particular, the normal
polarization of \tau) in the future B factories.Comment: 14 pages, latex, 5 figure
Higgs-mediated leptonic decays of B_s and B_d mesons as probes of supersymmetry
If tan(beta) is large, down-type quark mass matrices and Yukawa couplings
cannot be simultaneously diagonalized, and flavour violating couplings of the
neutral Higgs bosons are induced at the 1-loop level. These couplings lead to
Higgs-mediated contributions to the decays B_s -> mu+ mu- and B_d -> tau+ tau-,
at a level that might be of interest for the current Tevatron run, or possibly,
at B-factories. We evaluate the branching ratios for these decays within the
framework of minimal gravity-, gauge- and anomaly-mediated SUSY breaking
models, and also in SU(5) supergravity models with non-universal gaugino mass
parameters at the GUT scale. We find that the contribution from gluino loops,
which seems to have been left out in recent phenomenological analyses, is
significant. We explore how the branching fraction varies in these models,
emphasizing parameter regions consistent with other observations.Comment: Revised to accommodate minor changes in original text and update
reference
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