320 research outputs found
Semileptonic transitions in QCD
The form factors relevant to
decays are calculated in the framework of the three point QCD sum
rules approach. The heavy quark effective theory prediction of the form factors
are obtained. The total decay width and branching ratio for these decays are
also evaluated using the dependencies of these form factors.Comment: 4 pages, 4 figures and 3 tables. To be published in the proceedings
of the 14th International QCD Conference (QCD 08), Montpellier, France, 7-12
July 200
Double-Lepton Polarization Asymmetries and Polarized Forward Backward Asymmetries in the Rare b \to s \ell^+ \ell^- Decays in a Single Universal Extra Dimension Scenario
We study the double-lepton polarization asymmetries and single and
double-lepton polarization forward backward asymmetries of the rare b \to s
\ell^+ \ell^- mode within the Standard Model and in the
Appelquist-Cheng-Dobrescu model, which is a new physics scenario with a single
universal extra dimension. In particular, we examine the sensitivity of the
observables to the radius R of the compactified extra-dimension, which is the
new parameter in this new physics model.Comment: 20 Pages, 15 Figures and 1 Tabl
Semileptonic Decays in QCD Sum Rules
The form factors relevant to
decays are calculated in the framework of the three point QCD sum
rules approach. The heavy quark effective theory prediction of the form factors
as well as corrections to those form factors are obtained. A
comparison of the results for the ratio of form factors at zero recoil limit
and other values of with the predictions of the subleading Isgur-Wise
form factor application for is presented. The total
decay width and branching ratio for these decays are also evaluated using the
dependencies of these form factors. The results are in good agreement
with the constituent quark meson model and existing experimental data. The
case can also be detected at LHC in the near future.Comment: 28 Pages, 6 Figures and 9 Table
Flavor Changing Neutral Currents Transition of the to Nucleon in Full QCD and Heavy Quark Effective Theory
The loop level flavor changing neutral currents transitions of the
and are investigated in full
QCD and heavy quark effective theory in the light cone QCD sum rules approach.
Using the most general form of the interpolating current for ,
or , as members of the recently discovered sextet heavy baryons with
spin 1/2 and containing one heavy quark, the transition form factors are
calculated using two sets of input parameters entering the nucleon distribution
amplitudes, namely, QCD sum rules and lattice QCD inputs. The obtained results
are used to estimate the decay rates of the corresponding transitions. Since
such type transitions occurred at loop level in the standard model, they can be
considered as good candidates to search for the new physics effects beyond the
SM.Comment: 18 Pages and 13 Table
Determinants of private consumption
This paper looks at the evolution of consumption theory over time and critically examines the widely accepted permanent income / life cycle hypotheses concerning consumer behaviour in terms of the empirical evidence. Attention is also devoted to the role of time horizon, time preference and capital market imperfections in determining the consumption / savings split of individual consumers. The paper points out the forecasting inadequacies of an essentially Keynesian framework due to its insufficient attention to expectations and forward looking behaviour. The likely key influences on consumption trends in the Community over the medium to long run are examined including the reaction of consumption to both ongoing budgetary consolidation and financial liberalisation, the impact of taxation and social welfare reforms and finally the effect of demographic changes.consumption, consumers
Semileptonic to Nucleon Transitions in Full QCD at Light Cone
The tree level semileptonic and
transitions are investigated using the light cone QCD sum rules approach in
full theory. The spin--1/2, baryon with or , is
considered by the most general form of its interpolating current. The time
ordering product of the initial and transition currents is expanded in terms of
the nucleon distribution amplitudes with different twists. Considering two sets
of independent input parameters entering to the nucleon wave functions, namely,
QCD sum rules and Lattice QCD parameters, the related form factors and their
heavy quark effective theory limits are calculated and compared with the
existing predictions of other approaches. It is shown that our results satisfy
the heavy quark symmetry relations for lattice input parameters and b case
exactly and the maximum violation is for charm case and QCD sum rules input
parameters. The obtained form factors are used to compute the transition rates
both in full theory and heavy quark effective theory. A comparison of the
results on decay rate of with those predicted by other
phenomenological methods or the same method in heavy quark effective theory
with different interpolating current and distribution amplitudes of the
is also presented.Comment: 18 Pages and 16 Table
Wild oat nutrient uptake and release from residue
Non-Peer Reviewe
Performance Evaluation of Homogeneous Charge Compression Ignition Combustion Engine â A Review
The development of HCCI combustion technology has been drawing a great deal of attention from researchers. This survey explains ongoing research methodologies and results. HCCI combustion, other than conventional combustion, is purely based on chemical kinetics. At present the automobile sector faces the problem of emissions and needs to develop clean technologies. However, HCCI operation still has issues such as ignition control, combustion phasing control, operating range control, cold start, and UHC (unburned hydrocarbon) and CO (carbon monoxide) emissions. The challenge is to overcome these problems without compromising other engine parameters and performance. For HCCI, the mixture preparation is especially important, while the compression ratio, IVC (inlet valve closure) timing, inlet pressure, inlet temperature and EGR play a very prominent role in controlling it. This paper will go through a detailed discussion of all the above conditions
g_phi-pion-gamma coupling constant in light cone QCD sum rules
The coupling constant of g_phi-pion-gamma decay is calculated using light
cone QCD sum rules. A comparison of our result with the ones existing in the
literature is presented.Comment: 9 pages, 2 figure
Scalar Quarkonia at Finite Temperature
Masses and decay constants of the scalar quarkonia, with
quantum numbers are calculated in the framework of
the QCD sum rules approach both in vacuum and finite temperature. The masses
and decay constants remain unchanged up to but they start to
diminish with increasing the temperature after this point. At near the critic
or deconfinement temperature, the decay constants reach approximately to 25% of
their values in vacuum, while the masses are decreased about 6% and 23% for
bottom and charm cases, respectively. The results at zero temperature are in a
good consistency with the existing experimental values and predictions of the
other nonperturbative approaches. Our predictions on the decay constants in
vacuum as well as the behavior of the masses and decay constants with respect
to the temperature can be checked in the future experiments.Comment: 12 Pages, 9 Figures and 2 Table
- …