31 |
The Standard Model Analyasis Of The Cp Violation In The Inclusive Semileptonic B-meson DecaysEygi, Zeynep Deniz 01 February 2005 (has links) (PDF)
Being a flavor changing neutral current process, inclusive semileptonic B- meson decays provide reliable testing grounds for the Standard Model at the loop level. They are also importanat in the CKM phenomology and investing the CP violation due to the existence of sizable interference terms in the decay amplitude. In this work , the rare inclusive semileptonic B- meson decays for (lepton is electron ,muon , tau) are investigated in the context of the Standard Model.The differential branching ratio, forward-backward asymmetry ,CP &ndash / violating asymmetry and CP &ndash / violating asymmetry in the forward-backward asymmetry in these processes are examined.The dependencies of these physical parameters on the Standard Model parametres are analyzed by paying a special attention to the long distance effects. Although the branching ratios predicted for the inclusive semileptonic B- meson decays are relatively small because of CKM suppression , it has been found that there is a significant ACP and ACP(AFB) for these processes.
|
32 |
Model Independent Analysis Of Rare Exlusive B-meson DecaysCakmak, Kerim Mehmet 01 January 2004 (has links) (PDF)
Using the general, model indepenent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for l+ and l- for the effective B -> / K(K*)l+l- decays has been calculated. Existence of regions of Wilson coefficients for which the branching ratio coincides with the Standard Model result, while the lepton polarizations differ from the standard model prediction is expected. Hence, studying lepton polarizations in these regions of Wilson coefficients may be helpful in establishing new physics beyond standard model.
|
33 |
The early development of Islamic fiqh in Kûfah with special reference to the works of Abû Yûsuf and Shaybânî /Ansari, Zafar Ishaq January 1966 (has links)
No description available.
|
34 |
Scalar Meson Effects In Radiative Decays Of Vector MesonsKerman Solmaz, Saime 01 November 2003 (has links) (PDF)
The role of scalar mesons in radiative vector meson decays is
investigated. The effects of scalar-isoscalar f_{0}(980) and
scalar-isovector a_{0}(980) mesons are studied in the mechanism of the radiative Phi-> / pi{+}pi{-}gamma and
phi-> / pi{0}eta gamma decays, respectively. A
phenomenological approach is used to study the radiative
phi-> / pi{+}p{-}gamma decay by considering the
contributions of sigma-meson, rho-meson and f_{0}-meson.
The interference effects between different contributions are
analyzed and the branching ratio for this decay is calculated. The
radiative phi-> / pi{0}eta gamma decay is studied
within the framework of a phenomenological approach in which the contributions of rho-meson, chiral loop and a_{0}-meson are
considered. The interference effects between different
contributions are examined and the coupling constants g_{phi
a_{0} gamma} and g_{a_{0}K{+}K{-}} are estimated using the experimental branching ratio for the
phi-> / pi{0}eta gamma decay. Furthermore, the
radiative rho{0}pi{+}pi{-}gamma$ and
rho{0}-> / pi{0}pi{0}gamma decays are studied to
investigate the role of scalar-isoscalar sigma-meson. The
branching ratios of the rho{0}-> / pi{+}pi{-}gamma
and rho{0}-> / pi{0}pi{0}gamma decays are
calculated using a phenomenological approach by adding to the
amplitude calculated within the framework of chiral perturbation
theory and vector meson dominance the amplitude of sigma-meson
intermediate state. In all the decays studied the scalar meson
intermediate states make important contributions to the overall
amplitude.
|
35 |
Space Radiation Environment And Radiation Hardness Assurance Tests Of Electronic Components To Be Used In Space MissionsAmutkan, Ozge 01 July 2010 (has links) (PDF)
Space radiation is significantly harmful to electronic Components. The operating time, duration and orbit of the space mission are affected by the characteristic of the radiation environment. The aging and the performance of the electronic components are modified by radiation. The performance of the space systems such as electronic units, sensors, power and power subsystem units, batteries, payload equipments, communication units, remote sensing instruments, data handling units, externally located units,
and propulsion subsystem units is determined by the properly functioning of various electronic systems. Such systems are highly sensitive against space radiation.
The space radiation can cause damage to electronic components or functional failure on the electronics. A precisely methodology is needed to ensure that space radiation is not a threat on the functionality and performance of the electronics during their operational lives. This methodology is called as &rdquo / Radiation Hardness Assurance&rdquo / . In
this thesis, the hardening of electronics against space radiation is discussed.
This thesis describes the space radiation environments, physical mechanisms, effects of space radiation, models of the space radiation environment, simulation of the Total
Ionizing Dose, and &rdquo / Radiation Hardness Assurance&rdquo / which covers Total Ionizing Dose and Single Event Effects testing and analyzing of the electronics.
|
36 |
Lepton Flavor Violation In The Two Higgs Doublet ModelSundu, Hayriye 01 June 2007 (has links) (PDF)
The lepton flavor violating interactions are interesting in the sense that they are sensitive the physics beyond the standard model and they ensure considerable information about the restrictions of the free parameters, with the help of the possible accurate measurements. In this work, we investigate the lepton flavor
violating H+ ! W+l and the lepton flavor conserving H+ ! W+l decays in the general two Higgs doublet model and we estimate decay widths of these decays. After that, we analyze lepton
flavor violating decay !
i in the same model and calculate its branching ratio. We observe that the
experimental results of the processes under consideration can give comprehensive
information about the physics beyond the standard model and the existing free
parameters.
|
37 |
Scalar Mesons In Radiative Phi-meson Decays Into Charged K-meson StatesOzturk, Fahri 01 June 2008 (has links) (PDF)
The role of $f_{0}(980)$ and
$a_{0}(980)$ scalar meson intermediate states in the mechanism of
radiative $phi (1020)$ meson decay into two charged $K (494)$
mesons and a photon $phirightarrow K^{+} + K^{-} + gamma$ is
investigated. For the contribution of scalar meson intermediate
state two models are considered. In the kaon-loop model, the scalar
meson intermediate state couples the final state to the initial
$phi$ meson through a charged kaon-loop. The second model, called
no-structure model, consist of point-like coupling of intermediate
scalar meson state to the initial state. It is found that in the
kaon-loop model, scalar meson intermediate state results in a
considerable modification of the pure Bremsstrahlung photon
spectrum.
|
38 |
Properties Of Light And Heavy Baryons In Light Cone Qcd Sum Rules FormalismAzizi, Kazem 01 March 2009 (has links) (PDF)
In this thesis, we investigate the masses, form factors and magnetic dipole moments of some light octet, decuplet and heavy baryons containing a single heavy quark in the framework of the light cone QCD sum rules. The magnetic dipole moments can be measured considering radiative transitions within a multiplet or between multiplets.
Analyzing the transitions among the baryons and calculating the above mentioned parameters can give us insight into the structure of those baryons. In analyzing the aforementioned processes, the transition form factors play a crucial role. In this thesis, the form factors for these transitions are calculated using the light cone QCD sum rules approach.
In the limit when the light quark masses are equal, mu = md = ms, QCD has an SU(3) flavour symmetry which can be used to classify the light baryons. This classification results in the light decuplet, octet and singlet baryons. The baryons containing single heavy quark, on the other hand, can be classified according to the spin of the light degrees of freedom in the heavy quark limit, mQ -> / infinity. QCD at low energies, when the baryons are formed, is a non-perturbative theory. Hence, for phenomenology of the baryons, the QCD sum rules as a more powerful non-perturbative approach is
used.
Understanding the properties of nucleons is one of the main objectives of QCD. To investigate the properties of the nucleons, the axial N-Delta(1232) transition form factors
are calculated within the light cone QCD sum rules method. A comparison of our results on those form factors with the predictions of lattice QCD and quark model is presented. The nucleon electromagnetic form factors are also calculated in the same framework using the most general form of the nucleon interpolating current. Using two forms of the distribution amplitudes (DA&rsquo / s), predictions for the form factors are presented and compared with existing experimental data. It is shown that our results describe the existing experimental data remarkably well.
Another important property of the baryons is their magnetic moments. The magnetic moments of the heavy Xi_Q (Q = b or c) baryons containing a single charm or bottom quark are calculated within the light cone QCD sum rules approach. A comparison of our results with the predictions of other approaches, such as relativistic and nonrelativistic quark models, hyper central model, Chiral perturbation theory, soliton and skyrmion models is presented. Moreover, inspired by the results of recent experimental discoveries for charm and bottom baryons, the masses and magnetic moments of the heavy baryons with J^2P = 3/2^+ containing a single heavy quark are studied also within the light cone QCD sum rules method. Our results on the masses of heavy
baryons are in good agreement with predictions of other approaches, as well as with the existing experimental values. Our predictions on the masses of the states, which
are not experimentally discovered yet, can be tested in the future experiments. A comparison of our results on the magnetic moments of these baryons and the hyper
central model predictions is also presented.
|
39 |
Nuclear Spinodal Instabilities In Stochastic Mean-field ApproachesEr, Nuray 01 August 2009 (has links) (PDF)
Nuclear spinodal instabilities are investigated in non-relativistic
and relativistic stochastic mean-field approaches for charge
asymmetric and charge symmetric nuclear matter. Quantum statistical
effect on the growth of instabilities are calculated in
non-relativistic approach. Due to quantal effects, in both symmetric
and asymmetric matter, dominant unstable modes shift towards longer
wavelengths and modes with wave numbers larger than the Fermi
momentum are strongly suppressed. As a result of quantum statistical
effects, in particular at lower temperatures, amplitude of density
fluctuations grows larger than those calculated in semi-classical
approximation.
Relativistic calculations in the semi-classical limit are compared
with the results of non-relativistic calculations based on
Skyrme-type effective interactions under similar conditions. A
qualitative difference appears in the unstable response of the
system: the system exhibits most unstable behavior at higher baryon
densities around $rho_{B}=0.4 rho_{0}$ in the relativistic
approach while most unstable behavior occurs at lower baryon
densities around $rho_{B}=0.2 rho_{0}$ in the non-relativistic
calculations.
|
40 |
Spinodal Instabilities In Symmetric Nuclear Matter Within A Density-dependent Relativistic Mean-field ApproachDanisman, Betul 01 August 2011 (has links) (PDF)
The nuclear matter liquid-gas phase transition is expected to be a signal of nuclear
spinodal instabilities as a result of density fluctuations. Nuclear spinodal
instabilities in symmetric nuclear matter are studied within a stochastic relativistic
density-dependent model in semi-classical approximation. We use two
parameterization for the Lagrange density, DDME1 and TW sets. The early
growth of density fluctuations is investigated by employing relativistic Vlasov
equation based on QHD and discussed the cluster size of the condensations
from the early growth of density correlation functions. Expectations are that
hot nuclear matter behaves unstable around &rho / b &asymp / &rho / 0/4 (below the saturation
density) and at low temperatures. We therefore present our results at low temperature
T=1 MeV and at higher temperature T=5 MeV, and also at a lower
initial baryon density &rho / b = 0.2 &rho / 0 and a higher value &rho / b = 0.4 &rho / 0 where unstable
behavior is within them.
Calculations in density-dependent model are compared with the other calculations
obtained in a relativistic non-linear model and in a Skyrme type nonivrelativistic model. Our results are consistent with them. Qualitatively similar
results show that the physics of the quantities are model-independent. The size
of clusterization is estimated in two ways, by using half-wavelength of the most
unstable mode and from the width of correlation function at half maximum. Furthermore,
the average speed of condensing fragments during the initial phase of
spinodal decomposition are determined by using the current density correlation
functions.
|
Page generated in 0.0129 seconds