arXiv subjects
Publications and source records attributed to Ajay Kumar Rai.
Hadron spectroscopy is an important tool towards the study of internal quark dynamics in a composite system. The present article focuses on the study of resonance spectra of strange baryons with S=-2, -3. The non-relativistic approach utilizes screened potential as hypercentral one to obtain masses. The spin-dependent part for all possible hyperfine states has been incorporated.
In last few years the experimental evidence of charmed mesons is increasing remarkably. In the present work we systematically studied the $D$ meson by employing Regge phenomenology. By assuming the existence of the quasilinear Regge trajectories, several relations between Regge slope, intercept, and meson masses have been extracted. With the aid of these derived relations, Regge parameters are evaluated in both the ($J,M^{2}$) and ($n,M^{2}$) planes to obtain the mass spectra of $D$ meson. In the forthcoming years, we believe that more candidates will be reported and our predictions could provide useful information for future experimental evidences.
In this article, the linear plus modified Yukawa potential (LIMYP) is used as the quark antiquark interaction potential for the approximate analytical bound state solution of the Klein Gordon equation in three-dimensional space. The energy eigenvalues and associated wavefunction are obtained by solving the Klein Gordon equation analytically using the Nikiforov Uvarov (NU) method. The mass spectra of heavy mesons such as charmonium $(c\bar{c})$, bottomonium $(b\bar{b})$, and $b\bar{c}$ for various quantum states are obtained using the energy spectra expression. In comparison to experimental data, graphical modification of acquired mass spectra of heavy mesons with the parameter employed in the energy equation and the current potential provides good results.
An approximate bound state solution of the Klein-Gordon equation is derive analytically for the 3-dimensional space with a combination framework of linear plus modified Yukawa Potential (LIMYP) using the Nikiforov-Uvarov (N-U) method for obtaining the energy eigenvalues and corresponding wave function. A detailed study of mass spectra of all combination sets of heavy-light flavor mesons vis-a-vis $(Ks/Kq; K= C, B)$ is investigated by treating both heavy-light flavor mesons non-relativistic with an effective quark-antiquark interaction potential for different quantum states. Along with that, an elucidated graphical representation is scrutinized with the calculated mass spectra obtained from the energy eigenvalue against the corresponding variables for all the combination sets of heavy-light flavors mesons. Therefore, the current framework potential provides excellent reconciliation with the experimental data of states known to date and minuscule \% difference in lower quantum states, which increases with higher quantum states that can be correlated with the higher screening factor coming into the account.
In the present work, the mass-spectra of the light mesons, the kaons ($u\overline{s}$) and strangeonium ($s\overline{s}$) is systematically studied within the framework of Regge phenomenology. Several relations between Regge slope, intercept, and meson masses are extracted with the assumption of linear Regge trajectories. Using these relations the ground state masses ($1^{1}S_{0}$ and $1^{3}S_{1}$) of the pure $s\overline{s}$ states are evaluated. Further, the Regge slopes are extracted for kaons and strangeonium to obtain the orbitally excited state masses in the ($J,M^{2}$) plane. Similarly, the values of Regge parameters are calculated in the ($n,M^{2}$) plane for each Regge trajectory and obtain the radially excited state masses of mesons lying on that Regge trajectory. We compared our obtained spectrum with the experimental observations where available and with the predictions of other theoretical approaches. Here, we predict the possible quantum numbers of several recently observed experimental states, which still require further verification, and also evaluate the higher orbital and radial excited states that may be detected in the near future. We expect our predicted results could provide valuable information for future experimental searches for missing excited kaons and strangeonium mesons.
We calculate the mass spectra of $Λ_{c}$, $Ξ_{c}$, $Σ_{c}$, $Ξ_{c}^{'}$, and $Ω_{c}$ baryons in the framework of quark-diquark configuration using relativistic flux tube model. The spin-dependent interactions are included in the j-j coupling scheme to find complete mass spectra. We satisfactorily describe the known singly charmed baryons in quark-diquark configuration. The possible spin-parity $ J^{P} $ quantum numbers are assigned to several experimentally observed states. Furthermore, some useful mass predictions are given for more excited states that are reasonably consistent with other model predictions for lower excited states. {From the obtained results the Regge trajectories for these singly charmed baryons are constructed in the ($J,M^{2}$) plane and the properties like linearity, parallelism and equidistant are verified.} Also, these predictions should be tested in future experiments.
The present article contains the descriptive study of light strange baryons $Λ$, $Σ$, $Ξ$, and $Ω$. The Regge phenomenology with quasi-linear Regge trajectories has been employed and the relations between Regge slopes, intercepts, and baryon masses have been extracted. With the aid of these relations, ground state masses are obtained for $Ξ$ and $Ω$ baryons. Further, the Regge parameters have also been estimated to calculate the excited state masses for $Λ$, $Σ$, $Ξ$, and $Ω$ baryons in both the $(J,M^{2})$ and $(n,M^{2})$ planes. The obtained results are compared with available experimental data and various theoretical approaches. The spin-parity of recently observed light baryons are predicted in this work and our predictions may be useful in future experimental searches of these baryons and their $J^{P}$ assignments.
Using the Hypercentral Constituent Quark Model (hCQM), the mass spectra of doubly heavy baryons $Ξ_{cb}$ and $Ξ_{bb}$ are determined. The model describes an interaction inside the baryonic system. Screened potential has been considered as confining potential with color-Coloumb potential to enumerate the masses of baryonic states. Regge trajectories have been plotted in $(J, M^2)$ plane. The properties like magnetic moment and radiative decay width have been determined using the obtained results.
In this paper, we presented the mass spectra of the doubly heavy $Ω$ baryons containing one light (strange) quark and two heavy (charm and bottom) quarks. Our predicted masses can be consider to determine the $J^p$ value for the resonances detected by experimental facilities in future. The masses of ground excited states (1S-6S, 1P-3P, 1D-2D, 1F-2F) are calculated for all possible $J^p$ values, using the Hypercentral Constituent Quark Model (hCQM), by employing screened potential as confining potential with color-Coloumb potential. Regge trajectories are also plotted in $(J, M^2)$ plane for natural and unnatural parities. Doubly heavy Omega states are not declared yet by any experimental facility. We compared our results to the predictions gained from other theoretical approaches, and we found that our predictions are quite close to those of them. Other properties such as magnetic moment (for spin state $\frac{1}{2}$ and $\frac{3}{2}$) and radiative decay width are calculated using the enuerated masses.
In the present article the mass spectrum, decay constant, weak decay widths, life time and branching fraction ratios and electromagnetic transition widths are calculated for ground and radially excited $B_c$ meson. To calculate the above properties the Schrödinger equation has been solved numerically for the potential. The potential employed consists of relativistic correction in the framework of pNRQCD, added to the Cornell potential. The calculated results are compared with available experimental and theoretical results.
In contrast to past studies, the current paper is focused on baryons, and all four isospin states have been independently generated using u and d quarks with various constituent masses. The hypercentral Constituent Quark Model (hCQM) serves as the theoretical foundation for computing the resonance masses. The spin-dependent and first order correction terms are added to the confining potential, which is assumed to be in linear form. The resulting results have been contrasted with a wide range of methodologies and experimentally practicable states. Regge trajectories for (n,M^2) and (J,M^2) have also been displayed in addition to mass spectra.
Inspired by the lower statistical information in the bottom {\bf sector, in this paper, we} calculate the masses and the strong decays of excited $B$ and $B_s$ mesons in the framework of heavy quark effective theory (HQET). Using an effective chiral Lagrangian approach based on heavy quark spin-flavor and light quark chiral symmetry, we explore the flavor independent parameters $Δ_F^{(c)} = Δ_F^{(b)}$ and $λ_F^{(c)} = λ_F^{(b)}$ to calculate the masses of experimentally unknown bottom mesons. Our predictions are consistent with the available experimental results and other theoretical studies. Their strong decay to the ground state bottom mesons plus light pseudoscalar mesons is calculated in terms of the square of the couplings $g_H$, $g_S$, $g_T$, $g_X$, $g_Y$, and $g_R$. The weighted average value of the couplings $g_H$, $g_S$ and $g_T$ {\bf is} obtained in the charm sector [Phys. Rev. D \textbf{86}, 054024 (2012)] by fitting the calculated decay widths with experimental measurements, which will be used in the present study to analyze the strong decays of excited open bottom mesons. Moreover, the ratio of the decay rates is also predicted, which can be countered with future experimental data.
We investigated the four-quark systems with quark structures of $cs\bar{c}\bar{s}$, $cq\bar{c}\bar{s}$, $bs\bar{b}\bar{s}$, and $bq\bar{b}\bar{s}$ in the framework of the non-relativistic quark model, motivated by the recent observation of exotic resonances X(4140), X(4274), X(4350), X(4500), and X(4700) reported by several experiment collaborations. The colour antitriplet-triplet configuration of diquark-antidiquark combinations with all conceivable quantum numbers have been used to calculate their masses. The results reveal that if the colour structure of the diquark-antidiquark configuration is $\bar{3}_{c} \otimes 3$, the tetraquarks structures may occur otherwise may observed as resonance. The X(4274) state, can be defined as the $J^{PC}$=$2^{++}$ tetraquark state, while the X(4140) state can be regarded as the $J^{PC}$=$1^{++}$ tetraquark state in this calculation. When radial excitation is considered, X(4700) may be explained as a 2S radial excited tetraquark state with $J^{PC}$=$0^{++}$. The orbitally excited states Y(4626), Y(4630) and Y(4660) can be explained as P-wave tetraquark with quantum number $1^{--}$. The masses of [$bs\bar{b}\bar{s}$] and [$bq\bar{b}\bar{s}$] are found to be in the range between 10.5 GeV- 11.5 GeV and are very close to two-meson thresholds.
$Ω^{-}$ baryon with sss quarks has been scarcely observed in the experiments so far and has been exploited through many theoretical studies only. Here, an attempt has been made to explore properties of $Ω$ with hypercentral Constituent Quark Model (hCQM) with a linear confining term. The resonance mass spectra has been obtained for 1S-4S, 1P-4P, 1D-3D and 1F-2F respectively. The Regge trajectory has been investigated for the linear nature based on calculated data alongwith the magnetic moment. The present work has been compared with various approaches and known experimental findings.
The mass spectra of light-heavy tetraquarks $cq\bar{c}\bar{q}$ (q= u, d) are computed in a non-relativistic diquark model with one-gluon exchange plus confining potential. In the diquark model, a $cq\bar{c}\bar{q}$ state is regarded to be made of a light-heavy diquark (qc) and an antidiquark $\bar{q}\bar{c}$ in triplet and antitriplet colour configuration respectively. The masses of charm mesons were calculated in order to fit the model parameters used to create the masses of tetraquarks and therefore enhance the model's reliability. The masses of $(cq\bar{c}\bar{q})$ tetra-quark states are determined to be in the range of 3.8 GeV - 4.7 GeV, which is consistent with the experimentally reported charmonium-like states. In particular, the $Z_{c}(3900)$, $Z_{c}(4430)$, and $ψ(4660)$ tetraquarks, which have been seen experimentally, may all be described by our model.
In this article, we study the mass spectra of baryons containing two heavy quarks; charm-charm ($cc$) and bottom-charm ($bc$) with a light quark ($u,d,s$) within the framework of Regge phenomenology. With the assumption of linear Regge trajectories we have derived the relations between slope ratios, intercepts, and baryon masses. Using these relations, the ground state masses of $Ξ_{cc}$, $Ξ_{bc}$, $Ω_{cc}$, and $Ω_{bc}$ baryons are obtained. The values of Regge slopes and Regge intercepts are extracted for these baryons to estimate the excited state masses in both the ($J,M^{2}$) and ($n,M^{2}$) planes. Our obtained results are compared with the experimental observations where available and other theoretical predictions, which could be a valuable addition to the interpretations of experimentally unknown heavy baryon spectra.
The spectroscopy of light, strange baryons have been an important aspect with still unknown resonances and intrinsic baryonic properties. The present document is focused on the $Δ$ baryons unlike earlier work, here all the four isospin states have been separately obtained treating u and d quarks with different constituent masses. The theoretical framework for calculating the resonance masses is hypercentral Constituent Quark Model (hCQM). The confining potential is taken as of linear form alongwith the addition of spin-dependent as well as first order correction term. The results obtained have been compared with many varied approaches as well as experimental available states. In addition to mass spectra, Regge trajectories for (n,$M^{2}$) and (J,$M^{2}$) have been plotted. The magnetic moment as well as transition magnetic moment have been calculated using effective quark mass. The radiative decay width has been studied for $Δ^{+}$ and $Δ^{0}$ channels.
We enumerated ground and excited state masses of singly heavy bottom-strange baryons using the Hypercentral Constituent Quark Model (hCQM). The screening potential is used with color-Coulomb potential, as the confining potential. We determine the possible $J^P$ values to recently observed excited states like, $Ξ_b(6100)$, $Ξ_b(6227)$, $Ξ_b(6327)$, $Ξ_b(6333)$ and four $Ω_b(6316,6330,6340,6350)$ states. The Regge trajectories are plotted in $(J, M^2)$ plane to assign the $J^P$ values and quantum numbers to recently observed states. Using the calculated spectroscopic data, properties such as magnetic moment, transition magnetic moment, radiative decay width, and strong decay width are also investigated for all singly heavy bottom-strange baryonic system.