arXiv subjects
Publications and source records attributed to Alka Upadhyay.
The study of fully light tetraquark states composed solely of the light quarks u, d, and s provides an essential framework to understand the underlying dynamics of low-energy Quantum Chromodynamics (QCD). Within the framework of SU(3)f flavor symmetry, these states are classified into different multiplets, giving rise to a rich spectrum of non-strange, singly strange, doubly strange, and hidden-strangeness configurations.
The charm ($D$) and charm-strange ($D_s$) mesons are investigated in a variational scheme using Gaussian trial wave functions. The Hamiltonian contains Song and Lin potential with a constant term dependent on radial and orbital quantum numbers. The Gaussian wave function used has a dependence on radial distance $r$, radial quantum number $n$, orbital quantum number $l$ and a trial parameter $μ$. The obtained spectra of $D$ and $D_s$ mesons are in good agreement with other theoretical models and available experimental masses. The mass spectra of $D$ and $D_s$ mesons are also used to plot Regge trajectories in the ($J$, $M^2$) and ($n_r$, $M^2$) planes. In ($J$, $M^2$) plane, both natural and unnatural parity states of $D$ and $D_s$ mesons are plotted. The trajectories are parallel and equidistant from each other. The two-body strong decays of $D$ and $D_s$ are analyzed in the framework of heavy quark effective theory using computed masses. The strong decay widths are given in terms of strong coupling constants. These couplings are also estimated by comparing them with available experimental values for observed states. Also, the partial decay width ratios of different states are analyzed and used to suggest assignments to the observed states. We have assigned the spin-parity to newly observed $D^*_{s2}(2573)$ as the strange partner of $D^*_2(2460)$ identified as $1^3P_2$, $D_1^*(2760)$ and $D^*_{s1}(2860)$ as $1^3D_1$, $D^*_3(2750)$ and $D^*_{s3}(2860)$ as $1^3D_3$, $D_2(2740)$ as $1D_2$, $D_0(2550)$ as $2^1S_0$, $D^*_1(2660)$ and $D^*_{s1}(2700)$ as $2^3S_1$, $D^*_J(3000)$ as $2^3P_0$, $D_J(3000)$ as $2P_1$, $D^*_2(3000)$ as $1^3F_2$ states.
The magnetic octupole moment of $J^P= \frac{3}{2}^+$ decuplet baryons are discussed in the statistical framework, treating baryons as an ensembles of quark-gluon Fock states. The probabilities associated with multiple strange and non-strange Fock states depict the importance of sea in spin, flavor $\&$ color space, which are further merged into statistical parameters. The individual contribution of valence and sea (scalar, vector and tensor) to the magnetic octupole moment is calculated. The symmetry breaking in both sea and valence is experienced by a suppression factor $k(1-C_l)^{n-1}$ and a mass correction parameter 'r', respectively. The factor $k(1-C_l)^{n-1}$ systematically reduces the probabilities of Fock states containing multiple strange quark pairs. The octupole moment value is obtained -ve for $Δ^{++}, Δ^+, Σ^{*+}$ and +ve for $Δ^{-}, Σ^{*-}, Ξ^{*-}, Ω^-$ baryons with the domination of scalar (spin-0) sea. The computed results are compared with existing theoretical predictions, demonstrating good consistency. These predictions may serve as valuable inputs for future high-precision experiments and theoretical explorations in hadron structure.
The study of exotic multi-quark states has garnered significant attention recently, particularly in heavy-quark dynamics within quantum chromodynamics (QCD). We perform a comprehensive spectroscopic analysis of fully heavy pentaquark states with quark configurations $cccc\bar{c}$ and $bbbb\bar{b}$, considering spin-parity quantum numbers $J^P = 1/2^-$, $3/2^-$, and $5/2^-$. We construct the color-spin wavefunctions to explore the internal structure and mixing effects in these exotic states. Using an extended form of the Gursey-Radicati mass formula by incorporating spin-dependent interactions, we calculated their mass spectra. The modification incorporates effective mass contributions and hyperfine interactions to improve the predictive power for these hadronic states. We systematically analyze their quantum numbers, including spin parity, isospin, and the eigenvalues of the quadratic Casimir operator, which characterize their symmetry properties. The calculated mass spectra are compared with existing theoretical predictions to assess the stability and possible decay channels of these states. The calculated mass spectra exhibit a strong dependence on the interplay between spin interactions and color configurations, shedding light on the binding mechanism within these fully heavy multiquark systems. To gain further insights into their stability and decay properties, we investigated their potential production modes from $b$-hadron decays. Our analysis identifies dominant strong decay channels, providing critical theoretical benchmarks for distinguishing these states in future LHCb or EIC experiments. This study offers new insights into the role of heavy-quark dynamics in exotic hadron spectroscopy, serving as a stringent test for effective QCD-based models and lattice QCD predictions.
Motivated by the discovery of the fully charmed tetraquark state $X(6900)$ in the invariant mass spectrum of $J/ψ$ pairs by the LHCb collaboration, this study explores the potential existence of fully heavy pentaquark states. We systematically investigate the low-lying s-wave fully heavy pentaquark states across all possible configurations. The classification of these states is performed using the Young-Yamounachi bases through the Young-tableau technique. We analyze the mass spectrum and magnetic moments of pentaquarks with quantum numbers $J^P$= $\frac{1}{2}^{\pm}$,$\frac{3}{2}^{\pm}$ and $\frac{5}{2}^{\pm}$ utilizing effective mass and screened charge schemes. Our findings are compared with various theoretical models, providing valuable insights for future experimental studies.
We investigated the electromagnetic quadrupole transition of baryon decuplet ($J^P= \frac{3}{2}^+$) to octet ($J^P= \frac{1}{2}^+$) using the statistical framework together with the principle of detailed balance. The statistical approach assumed the expansion of hadrons in terms of various quark-gluon Fock states. By specifying the appropriate multiplicity in spin, color $\&$ flavor space, the relative probabilities of strange and non-strange quark-gluon Fock state are calculated. These probabilities further accumulated in the form of statistical parameters, highlighting the importance of sea quarks and gluons in the electromagnetic transition. Our calculations includes the individual contribution of valence and sea (scalar, vector and tensor ) to the transition moment of baryons. The effect of flavor SU(3) symmetry and its breaking in both valence and sea quarks is studied by incorporating the strange quark mass. The strangeness in the sea is constrained by a suppression factor $(1-C_l)^{n-1}$, which depends upon the free energy of gluons. The computed results get affected upto 60 $\%$ and exhibit the dominance of octet sea. The present work has been compared with updated experimental data and various theoretical predictions. The results obtained may offer important insights for future experimental studies.
We analyze the ground state pentaquark structures with a single heavy quark ($qqqq\Bar{Q}$) using various phenomenological models. The recent observations of singly heavy tetraquark structures at LHCb serve as a significant motivation for this investigation. We studied the symmetric 15-plet configuration of SU(3) flavor representation with the spin-parity assignment of $5/2^-$, representing the symmetric spin state for the pentaquark systems. We employed an extended Gursey-Radicati mass formula and an effective mass scheme to compute the mass spectra of pentaquark states. Additionally, the methodology of the screened charge scheme is introduced to calculate the magnetic moment assignments, specifically for configurations involving both charm and bottom quarks. We also proposed the potential production modes originating from the weak decay of heavy baryons. We identified the strong decay channels where pentaquark transitions into a light baryon and a heavy meson. Our analysis of mass spectra, magnetic moments, and possible strong decay channels helps us to explore the inner structure of pentaquarks and their underlying quark dynamics. This work not only augments the theoretical frameworks used to describe such systems but is also helpful for future experimental pursuits at facilities like LHCb, fostering further experimental validations and discoveries in heavy quark spectroscopy.
Motivated by the recent discovery of single heavy tetraquark structures, $T_{c\bar{s}0}^a (2900)^{++}$ and $T_{c\bar{s}0}^a(2900)^0$ by the LHCb collaboration, masses and magnetic moments of singly heavy pentaquark states are estimated in this work. To classify the singly heavy pentaquark structures, we employ the special unitary representation. By using the SU(3) flavor representation, we placed singly heavy pentaquark states into the allowed flavor multiples. Also, by using the extension of the Gursey-Radicati mass formula and the effective mass scheme, we estimated the masses of singly heavy pentaquark states. Further, magnetic moments of these states have been calculated using the effective mass and the screened charge techniques. A thorough comparison of our results shows reasonable agreement with the available theoretical data and may be helpful for future experimental studies.
We carried out the systematic analysis of the $s$-wave triply heavy pentaquarks with possible configurations like $q\Bar{q}QQQ$ and $qqQQ\Bar{Q}$, ($q = u, d, s$ and $Q = c, b$ quarks). Special unitary representations are utilized to study the classification scheme for triply heavy configurations like $q\Bar{q}QQQ$ and $qqQQ\Bar{Q}$. We classified the $q\Bar{q}QQQ$-type pentaquarks into an octet and $qqQQ\Bar{Q}$-type pentaquarks into sextet configurations with the help of SU(3) flavor representation. Also, with the help of SU(2) spin representation, we studied the possible spin assignments ($\frac{1}{2}^-$, $\frac{3}{2}^-$, and $\frac{5}{2}^-$) for ground state triply heavy pentaquarks. Furthermore, we used the formalism of the extended Gursey-Radicati mass formula and effective mass scheme to estimate the masses of triply heavy pentaquarks. Additionally, we calculated the magnetic moment assignments using the effective mass and screened charge schemes. The predicted outcomes align well with the existing theoretical data and benefit future studies. Our work provides a comprehensive framework that combines the theoretical aspects of SU(3) and SU(2) symmetries with practical predictions for observables, offering a strong foundation for experimental verification. This integrated approach enhances our understanding of the complex interactions within triply heavy pentaquarks and underscores their potential role in probing deeper into the dynamics of the strong force. These findings are crucial for designing future high-energy experiments that directly observe these exotic states and confirm their properties, paving the way for new insights into quantum chromodynamics.
By taking into light the discovery of pentaquark structures like $P_{ψs}^Λ(4338)^0$, $P_c(4380)$ and $P_c(4450)$, we performed the spectroscopy of hidden-bottom pentaquarks. By utilizing special unitary representations, we systematically classified the hidden bottom pentaquarks into two distinct configurations within the SU(3) flavor representation: the octet and decuplet. In this study, we employed an extended version of the GR mass formula along with the effective mass scheme to provide estimations of the masses associated with hidden-bottom pentaquarks. Furthermore, we extend our analysis to estimate the magnetic moments using the effective mass scheme and screened charge scheme. Moreover, by employing the effective Lagrangian, we computed the partial widths for the octet configuration. This comprehensive analysis offers crucial insights into the decay mechanisms and lifetimes of these exotic particles, enhancing our understanding of their fundamental properties. Our findings, which include calculations of masses and magnetic moments, demonstrate reasonable agreement with existing theoretical predictions.
In this paper, we comprehensively explore bottomonia mass spectra and their decay properties by solving the non-relativistic Schrodinger wave equation numerically with approximate quark-antiquark potential form. We also incorporate spin-dependent terms - spin-spin, spin-orbit, and tensor terms to remove mass degeneracy and to obtain excited states ($nS, nP, nD, nF, n = 1, 2, 3, 4, 5$) mass spectra. By using Van Royen - Weisskopf formula, we investigate leptonic decay constants, di-leptonic, di-gamma, tri-gamma, di-gluon decay widths and also incorporate first-order radiative corrections. We also computed radiative transition widths, which give a better insight into the non-perturbative aspects of QCD. The present results for mass spectroscopy and decay properties are in tune with available experimental values and other theoretical predictions. Our results may provide better insight to upcoming experimental information in the near future.
In this work, the multiquark approach is used to analyze the spectroscopy of hidden-charm pentaquark states, motivated by recent discoveries at the LHCb collaboration. Using the SU(3) flavor representation, pentaquarks having $J^P = 5/2^-$ are arranged into 10 (decuplet) of the SU(3) flavor multiplets. The masses of pentaquarks are calculated using the extension of the Gursey-Radicati mass formula and the effective mass scheme. Also, we calculated the magnetic moments of the hidden-charm pentaquarks using the effective mass and shielded charge technique. Further, we suggested the possible production modes for $J^P = 5/2^-$ pentaquarks from the decay of bottom baryons, which consist of pentaquark states as intermediate states. Our results for masses demonstrate reasonable agreement with the available data and our analysis for both masses and magnetic moments may be useful for future experimental studies.
An operator formalism is used on the wavefunction of baryons to compute their charge radii and quadrupole moments. Total anti-symmetric wavefunction in spin, color and flavor space is framed for $J^P=\frac{1}{2}^+$ nucleons and $J^P=\frac{3}{2}^+$ hyperons. To understand the importance of sea, statistical model is used in conjugation with the detailed balance principle. Within the statistical approach, the importance of sea with quarks and gluons are studied using the relevant probabilities that are associated with spin, flavor, and color space. The present work also focuses on individual contributions of valence and sea which contains terms of scalar, vector and tensor sea. The obtained results are in agreement with available theories and few experimental outcomes. Our computed results may provide important information for upcoming experimental findings.
Tetraquark states are classified using the $SU(6)_{sf}$ spin-flavor symmetry and Young tableau technique. Further, by using the extension of Gursey-Radicati mass formula, masses of tetraquark states are predicted upto good level of accuracy. Also, Decay channels and decay widths of tetraquark states are calculated and found to be in good agreement with the experimental and available theoretical data.
We studied $F$-wave bottom mesons in heavy quark effective theory. The available experimental and theoretical data is used to calculate the masses of $F$-wave bottom mesons. The decay widths of bottom mesons are analyzed to find upper bounds of the associated couplings. We also construct Regge trajectories for our predicted data in planes ($J$, $M^2$ ) and our results nicely fit on Regge lines. Our results may provide a crucial information for upcoming experimental studies.
By exploring heavy quark effective theory (HQET), we use theoretical available data for bottom mesons to analysis the masses and decays for n = 3 charm mesons. From the predicted masses, we studied ground state strong decay modes in terms of couplings. Comparing the decays with available total decay widths, we provide upper bounds on the associated couplings. We also plot Regge trajectories for our predicted data in planes (J, $M^2$ ) and ($n_r$, $M^2$ ) and estimated higher masses (n = 4) by fixing Regge slopes and intercepts. These Regge trajectories are used to clarify $D_2^*(3000)$ state's $J^P$ as 1F ($2^+$) state. The presented results may further get confirmation through upcoming experimental information.
The statistical model in combination with detailed balance principle is able to phenomenological calculate and analyze spin and flavor dependent properties like magnetic moments (with effective masses, effective charge, with both effective mass and effective charge), quark spin polarization and distribution, strangeness suppression factor. The magnetic moments of the octet baryons are analyzed within the statistical model, by putting emphasis on the SU(3) symmetry breaking effects generated by the mass difference between the strange and non strange quarks. The work presented here assume hadrons with a sea having admixture of quark-gluon Fock states. The results obtained have been compared with theoretical models and experimental data.
The mass formulae for the baryon octet and decuplet are calculated. These formulae are function of constituent quark masses and spin spin interaction terms for the quarks inside the baryons. The coefficients in the mass formulae is estimated by the statistical model for J/P=1/2+, J/P=3/2+, incorporating the contributions from \sea" containing uu; dd; ss pairs and gluons . The measured masses are presented and found to be matching good with some of the experimental and theoretical data.