arXiv subjects

Faisal Akram

Publications and source records attributed to Faisal Akram.

25 records · Page 2Linked to original sources

arXiv2014

Higher Hybrid Charmonia in an Extended Potential Model

The quark potential model for mesons and its extension for hybrid mesons are used to study the effects of radial excitations on the masses, sizes and radial wave functions at the origin for conventional and hybrid charmonium mesons. These results can help in experimentally recognizing hybrid mesons. The properties of conventional and hybrid charmonium mesons are calculated for the ground and radially excited states using the shooting method to numerically solve the required Schrodinger equation for the radial wave functions. We compare our results with the experimentally observed masses and theoretically predicted results of the other models. Our results have implications for scalar form factors, energy shifts, and polarizabilities of conventional and hybrid mesons. The comparison of masses of conventional and hybrid charmonium meson with the masses of recent discovered XYZ-particles is also discussed.

hep-ph↗

arXiv2013

B_{c} absorption cross sections by nucleons

The cross sections of $B_{c}$\ absorption by nucleons are calculated in meson-baryon exchange model using hadronic Lagrangian based on SU(4)/SU(5) flavor symmetries. The values of different coupling constants used in the model are obtained from vector meson dominance model, QCD sum rule or SU(4)/SU(5) flavor symmetries. Calculated values of cross sections are found to be significantly different from the previous study in which b-flavored hadron exchange is neglected. These results could be useful in calculating production rate of $B_{c}$ meson in relativistic heavy ion collisions.

nucl-th↗

arXiv2013

Hadronic absorption cross sections of $B_{c}$

The cross sections of $B_{c}$\ absorption by $π$ mesons are calculated using hadronic Lagrangian based on SU(5) flavor symmetry. Calculated cross sections are found to be in range 2 to 7 mb and 0.2 to 2 mb for the processes $B_{c}^{+}π\rightarrow DB$ and $B_{c}^{+}π\rightarrow D^{\ast}B^{\ast}$ respectively, when the monopole form factor is included. These results could be useful in calculating production rate of $B_{c}$ meson in relativistic heavy ion collisions.

nucl-th↗

arXiv2013

Dictionary Adaptation in Sparse Recovery Based on Different Types of Coherence

In sparse recovery, the unique sparsest solution to an under-determined system of linear equations is of main interest. This scheme is commonly proposed to be applied to signal acquisition. In most cases, the signals are not sparse themselves, and therefore, they need to be sparsely represented with the help of a so-called dictionary being specific to the corresponding signal family. The dictionaries cannot be used for optimization of the resulting under-determined system because they are fixed by the given signal family. However, the measurement matrix is available for optimization and can be adapted to the dictionary. Multiple properties of the resulting linear system have been proposed which can be used as objective functions for optimization. This paper discusses two of them which are both related to the coherence of vectors. One property aims for having incoherent measurements, while the other aims for insuring the successful reconstruction. In the following, the influences of both criteria are compared with different reconstruction approaches.

cs.IT↗

arXiv2011

Optimization of Neutrino Oscillation Parameters using Differential Evolution

We combine Differential Evolution, a new technique, with the traditional grid based method for optimization of solar neutrino oscillation parameters $Δm^2$ and $\tan^{2}θ$ for the case of two neutrinos. The Differential Evolution is a population based stochastic algorithm for optimization of real valued non-linear non-differentiable objective functions that has become very popular during the last decade. We calculate well known chi-square ($χ^2$) function for neutrino oscillations for a grid of the parameters using total event rates of chlorine (Homestake), Gallax+GNO, SAGE, Superkamiokande and SNO detectors and theoretically calculated event rates. We find minimum $χ^2$ values in different regions of the parameter space. We explore regions around these minima using Differential Evolution for the fine tuning of the parameters allowing even those values of the parameters which do not lie on any grid. We note as much as 4 times decrease in $χ^2$ value in the SMA region and even better goodness-of-fit as compared to our grid-based results. All this indicates a way out of the impasse faced due to CPU limitations of the larger grid method.

physics.comp-ph↗

arXiv2006

Equalization of Response Functions of SK and SNO

We have studied the equalization of the response functions of the SK and SNO for total event rate and event rate for the energy bins. To calculate the response functions of SNO, we have used the latest theoretical values of the cross section of the neutrino-deuteron CC process. By using these new theoretical values, we find that the trigger threshold of the SK at which its response function is equalized to the response function of SNO (at the trigger threshold of 6.75 MeV), is 8.5 MeV. This value is 0.1 MeV smaller than the value calculated using the old theoretical values of the cross section of neutrino-deuteron process. The use of these new theoretical values also produces a small change in the range of the energy bins where the response functions are equalized.

hep-ph↗

arXiv2002

Present Status of epsilon'/epsilon

We give the recent experimental results and theoretical analysis of CP violating ratio epsilon'/epsilon. The present status is discussed in the light of the standard model.

hep-ph↗