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Nosheen Akbar

Publications and source records attributed to Nosheen Akbar.

18 recordsLinked to original sources

Temperature dependence on Spectrum of Heavy Hybrid Mesons

In this work, temperature dependence on the masses of conventional and hybrid heavy quarkonium systems is investigated. For this, a thermally screened interaction is incorporated through Debye mass $(m_{D}(T))$ into the potential models of conventional and hybrid charmonium ($c\overline{c}$) and bottomonium ($b\overline{b}$) mesons (conventional and hybrid). Mass eigenvalues for S, P, D states of these mesons are computed by power series expansion method at different values of debye mass. Comparison with available lattice-QCD-inspired potentials and previous numerical studies show strong agreement and validate the efficiency of power-series technique for calculations of mass of heavy quarkonium at finite-temperature. Our results can be helpful to explore the recent experimentally determined states of charmonium and bottomonium.

hep-ph

Models for differential cross section in neutron-proton scattering and their implications

A few analytic exponential models of elastic differential cross section, constructed as purely phenomenological models, are proposed and tested. The models incorporate energy-dependent exponential slopes, power-law prefactors, and localized Gaussian modifications which are built to reproduce the observed dip region, supplemented in some cases by logarithmic $t$-dependent slopes. Simple additive sub-leading exponential contributions that represent charge conjugation and isospin roles are introduced in the models to increase applicability and quality of fit across elastic differential cross section data of $np$, $n\bar{p}$, $pp$, and $p\bar{p}$ elastic scattering. The models reproduce the characteristic features of the elastic scattering data such as the dip-bump structure, shrinkage of the forward peak, and controlled curvature that is localized around the dip. Parameters of the models are found by fitting the experimental data of elastic $np$ differential cross section in an energy range of $\sqrt{s}$ = 3.36 GeV to 26.02 GeV, across a momentum range of $0.065 \leq \mid t\mid \leq 5.341 \textrm{GeV}^{2}$. The parameter values and their ranges, obtained by $χ^{2}$ minimization are found within their assumed expected bounds with the $np$ data fitting. The total cross section, the slope parameter, the interaction radius, the total elastic cross section, the inelastic cross section, the ratios $σ_{el}/σ_{tot}$, and $σ_{inel}/σ_{tot}$ are predicted by the models for the $np$ scattering at all the energies, which show accurate quantitative agreement with their reference values. The results show that the proposed models not only provide accurate quantitative description of $np$ elastic differential cross section but also yield estimates of the observables that are consistent with theoretical expectations from Regge phenomenology and high-energy scattering constraints.

hep-ph

Mass Spectrum, Radii, and Radiative Decay Widths of Toponium

In this work, radial Schrodinger equation with a non-relativistic quark potential model (NRQPM) is solved numerically by employing the shooting method. Calculated numerical wave functions (or solutions) are used to compute the masses, root mean square (RMS) radii, $E1$ and $M1$ radiative transitions, and branching ratios of $S, P, D$ and $F$ states of toponium mesons ($t\overline{t}$). Calculated results are compared with recently available theoretical data. This work will be helpful for experimentalists in gaining a deeper understanding of toponium states.

hep-ph

Energy eigenvalues of quadratic, pure quartic and quartic anharmonic oscillators with variational method

In this work, the energy eigenvalues are calculated for the quadratic ($\frac{g^2 x^2}{2}$), pure quartic ($λx^4 $), and quartic anharmonic oscillators ($\frac{g^2 x^2}{2} + λx^4 $) by applying variational method. For this, simple harmonic oscillator wave functions are considered as trial wave functions to calculate the energies for the ground state and first ten excited states with $g = 1$ and $λ=1/4$. For quartic anharmonic oscillators, energy values are calculated at different values of $λ$ with $g=1$. These energies for the ground state are compared with available numerically calculated data. Maximum value of $\%$error is found to be 1.9977. To get more accurate results, a new set of trial wave functions is suggested. With the newly proposed wave functions, maximum value of $\%$ error for the energy values reduces to 0.561. In this work, energies for the ground and first five excited states of quartic anharmonic oscillators are reported at different values of $λ$. Dependence of $λ$ on the wave functions is observed and concluded that wave functions are converging (shrinking) by increasing the $λ$.

quant-ph

Models for differential cross section in proton-proton scattering and their implications at ISR and LHC energies

Few composite exponential models for the differential cross section are proposed to analyse the proton-proton ($pp$) elastic scattering at several energies. These proposed models are fitted to the data for $pp$ elastic differential cross section reported at CERN-ISR, LHC, and extrapolated energies of other models. These models have produced important features including dip-bump structure and shrinkage of the forward peak. Position of the dip is also well produced by our models for all the data across a broad energy range of $\sqrt{s}$ = 23 GeV, 23.5 GeV, 27.23 GeV, 30.7 GeV, 44.7 GeV, 52.8 GeV, 62.5 GeV, 200 GeV, 800 GeV, 2.76 TeV, 7 TeV, 8 TeV, 13 TeV, 14 TeV, 15 TeV, and 28 TeV. Employing these proposed models, elastic cross section, inelastic cross section, and total cross section are calculated at all the energies. Calculated results are compared with experimental data and theoretical results of other models. Implications of these results (obtained by models) related to the structure and dynamics of proton are discussed. The findings of this study emphasize the significance of combining theoretical and phenomenological approaches to accurately describe $pp$ elastic scattering at high energies and provide significant information to future LHC experiments for the investigation of differential cross section.

hep-ph

Mass Spectrum, Root Mean Square Radii, Form Factors and Charge Radii of Mesons

In this work, properties of charmonium, bottomonium and charmed-bottom mesons for S, P, D states are calculated with the selection of suitable trial wave functions for the non-relativistic potential model along with the incorporation of spin interactions. These trial wave functions are tested by calculating the masses of ground, radial and orbital excited states of mesons with the variational method. The mass predictions show good agreement with the available experimental data and theoretical predictions found by different methods. This indicates that these trial wave functions are appropriate for further study on mesons. These trial wave functions are used to calculate RMS radii, form factors and charged radii. Results show that RMS radii and charged radii have inverse relation with the masses of mesons, i.e., heavier mesons have smaller radii and vice versa. Momentum dependence of the form factors is studied graphically.

hep-ph

Spectrum of Hybrid Charmonium, Bottomonium and $B_c$ Mesons by Power Series Method

Power series method (PSM) is revisited to find the masses of S, P, and D states of conventional charmonium ($c\overline{c}$), bottomonium ($b\overline{b}$), and $B_c$ ($\overline{b}c$) mesons by assuming the solution of N-dimensional radial Schrodinger equation in series form. An extension in the potential model is proposed by fitting it with lattice data to study the hybrid mesons. The proposed potential model is used to find the masses of hybrid $c\overline{c}$, $b\overline{b}$, and $\overline{b}c$ mesons by applying the power series method. Calculated results are compared with theoretical findings and available experimental data. Our results can be helpful for the investigation of newly experimentally discovered charmonium, bottomonium, and $B_c$ states.

hep-ph

Spectrum and Decay Properties of Bottomonium Mesons

We calculate the spectrum and wave functions (WFs) of various states of bottomonium mesons ($b\overline{b}$) using a non-relativistic quark potential model (NRQPM). The calculated WFs are used to compute the radiative widths of various states of $b\overline{b}$. The strong decays widths of bottomonium states are also calculated using $^3P_0$ model by choosing simple harmonic oscillator wave functions (SHOWFs). The $β$ of SHOWFs for various states of the mesons are measured by fitting the numerical wave functions. The radiative and strong decay widths are used to calculate the branching ratios of $b\overline{b}$ mesons. We also compare our calculated masses and widths with available experimental data.

hep-ph

Masses, Radii and Regge Trajectories of $Σ_u^-$ State Hybrid Charmonium

In this paper, masses and radii of $Σ^-_u$ states hybrid charmonium mesons are calculated by numerically solving the Schrödinger equation with non-relativistic potential model. Results for calculated masses of $Σ^-_u$ states charmonium hybrid mesons are found to be close to the results obtained through lattice simulations. Calculated masses are used to construct Regge trajectories. It is found that the trajectories are almost linear and parallel.

hep-ph

Potential Model for $Σ_{u}^{-}$ Hybrid Meson State

In this paper, lattice simulations are used to propose a potential model for gluonic excited $Σ^-_u$ states of bottomonium meson . This proposed model is used to calculate radial wave functions, masses and radii of $Σ_u^-$ bottomonium hybrid mesons. Here, gluonic field between a quark and an antiquark is treated as in the Born-Oppenheimer expansion, and Schr$\ddot{o}$dinger equation is numerically solved employing shooting method. Results of calculated masses for $Σ^-_{u}$ state are in quite good agreement with the lattice simulations.

hep-ph

Decay Properties of Conventional and Hybrid $B_c$ Mesons

Spectrum, radial wave functions at origin, decay constants, weak decay widths, life time and branching ratios for radially excited conventional and hybrid $B_c$ mesons are derived within non-relativistic quark model framework employing Schr$\ddot{\textrm{o}}$dinger equation by shooting method. Calculated results are compared with available theoretical results and experimental observations. This work may help in identifying the new discovered $B_c$ meson states at CDF ,LHCb and ATLAS.

hep-ph

Decay Properties of Conventional and Hybrid Charmonium Mesons

In this paper, Schrodinger equation is numerically applied through non-relativistic potential model for deriving Spectrum, radial wave functions at origin, decay constants, lepton and photon decay widths for radial and orbital excited conventional as well as hybrid charmonium mesons. These calculated results are found in agreement with others theoretical results and with the experimental observations.

hep-ph

Properties of Bc Mesons and Variational Constraints on their Masses

Spectrum, radii, radial wave functions at origin, decay constants and momentum widths for radial and orbital excited $B_c$ mesons are derived within non-relativistic quark model framework through finding numerical solution of the Schrodinger equation by shooting method. Masses of orbitally excited states are derived with a more simpler method that is developed by combining the uncertainty and variational principles. Masses of $B_c$ mesons are also calculated by using Momentum widths. Besides calculations, theoretical results are compared with the experimental observations which have implications for scalar form factors and leptonic decays of $B_c$ mesons.

hep-ph

Conventional and Hybrid $B_c$ Mesons in an Extended Potential Model

Using our analytical expressions that well model the lattice simulations of the gluonic excitations, we use the extended quark potential model to study the effects of orbital and radial excitations on the masses and sizes of conventional and hybrid $B_c$ mesons. A non relativistic formalism is used to numerically calculate the wave functions using the shooting method; this allows us also calculating the $E1$, $M1$ radiative partial widths for conventional meson to meson and hybrid to hybrid transitions. We incorporate spin mixing and compare our calculated spectrum and decay widths with the available experimental $B_c$ masses and the theoretically predicted spectra and the decay widths by other groups. Our results can help consider both conventional and hybrid quantum numbers to $B_c$ mesons as experimental results become available.

hep-ph

Higher Hybrid Bottomonia in an Extended Potential Model

Using our extension of the quark potential model to hybrid mesons that fits well to the available lattice results, we now calculate the masses, radii, wave functions at origin, leptonic and two photon decay widths, E1 and M1 radiative transitions for a significant number of bottomonium mesons. These mesons include both conventional and hybrid ones with radial and angular excitations. Our numerical solutions of the Schrodinger equation are related to QCD through the Born-Oppenheimer approach. Relativistic corrections in masses and decay widths are also calculated by applying the leading order perturbation theory. The calculated results are compared with available experimental data and the theoretical results by other groups. We also identify the states of $Υ(10860)$, $Υ(11020)$, and $Y_b(10890)$ mesons by comparing their experimental masses and decay widths with our results.

hep-ph

Wave Function Based Characteristics of Hybrid Mesons

We propose some extensions of the quark potential model to hybrids, fit them to the lattice data and use them for the purpose of calculating the masses, root mean square radii and wave functions at the origin of the conventional and hybrid charmonium mesons. We treat the ground and excited gluonic field between a quark and an antiquark as in the Born-Oppenheimer expansion, and use the shooting method to numerically solve the required Schr$\ddot{\textrm{o}}$dinger equation for the radial wave functions; from these wave functions we calculate the mesonic properties. For masses we also check through a Crank Nichelson discretization. For hybrid charmonium mesons, we consider the exotic quantum number states with $ J^{PC} = 0^{+ -}, 1^{- +}$ and $2^{+ -}$. We also 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, magnetic polarizabilities, decay constants, decay widths and differential cross sections of conventional and hybrid mesons.

hep-ph

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

Dynamical implications of gluonic excitations in meson-meson systems

We study meson-meson interactions using an extended $q^2\bar{q}^2(g)$ basis that allows calculating coupling of an ordinary meson-meson system to a hybrid-hybrid one. We use a potential model matrix in this extended basis which at quark level is known to provide a good fit to numerical simulations of a $q^2\bar{q}^2$ system in pure gluonic theory for static quarks in a selection of geometries. We use a combination of resonating group method formalism and Born approximation to include the quark motion using wave functions of a $q\bar{q}$ potential within a cluster. This potential is taken to be quadratic for ground states and has an additional smeared $\frac{1}{r}$ (Gaussian) for the matrix elements between hybrid mesons. For the parameters of this potential, we use values chosen to 1) minimize the error resulting from our use of a quadratic potential and 2) best fit the lattice data for differences of $Σ_{g}$ and $Π_{u}$ configurations of the gluonic field between a quark and an antiquark. At the quark (static) level, including the gluonic excitations was noted to partially replace the need for introducing many-body terms in a multi-quark potential. We study how successful such a replacement is at the (dynamical) hadronic level of relevance to actual hard experiments. Thus we study effects of both gluonic excitations and many-body terms on mesonic transition amplitudes and the energy shifts resulting from the second order perturbation theory (i.e. from the respective hadron loops). The study suggests introducing both energy and orbital excitations in wave functions of scalar mesons that are modelled as meson-meson molecules or are supposed to have a meson-meson component in their wave functions.

hep-ph