Assignment Of Quantum Numbers Research Articles

Spectroscopic study of exotic fully-heavy tetraquark states [formula omitted] ([formula omitted])

In this article, we utilize the non-relativistic potential model to investigate the mass spectra of exotic fully-heavy tetraquark states QQQ̄Q̄ (Q∈{c,b}), specifically examining [cc][c̄c̄] and [bb][b̄b̄].We treat these states as diquark–antidiquark bound systems governed by a diquark–antidiquark color Coulomb plus confining linear potential.To determine the masses of the ground state and its radially and orbitally excited states for fully-heavy tetraquark states, we incorporate perturbative spin–spin, spin–orbit and spin–tensor interaction potentials.Our results of masses of nS, nP and nD states of fully heavy tetraquark states are compared with both other theoretical predictions and experimental data.Remarkably, our results closely align with theoretical as well as experimental observations.Furthermore, our findings also support the assignment of JPC quantum numbers to the recently observed structures by ATLAS, LHCb and CMS collaborations, including X(6600), X(6900) and X(7200).

ExoMol line lists – LVI. The SO line list, MARVEL analysis of experimental transition data and refinement of the spectroscopic model

ABSTRACT A semi-empirical IR/Vis line list, SOLIS, for the sulphur monoxide molecule 32S16O is presented. SOLIS includes accurate empirical rovibrational energy levels, uncertainties, lifetimes, quantum number assignments, and transition probabilities in the form of Einstein A coefficients covering the $X\, {}^{3}\Sigma ^{-}$$, a\, {}^{1}\Delta , b\, {}^{1}\Sigma ^{+}, A\, {}^{3}\Pi , B\, {}^{3}\Sigma ^{-}, A^{\prime \prime }\, {}^{3}\Sigma ^{+}, A^{\prime }\, {}^{3}\Delta$, and $e\, {}^{1}\Pi$ systems and wavenumber range up to 43 303.5 cm−1 (≥230.93 nm) with J ≤ 69. SOLIS has been computed by solving the rovibronic Schrödinger equation for diatomics using the general purpose variational code Duo and starting from a published ab initio spectroscopic model of SO (including potential energy curves, coupling curves, (transition) dipole moment curves) which is refined to experimental data. To this end, a database of 50 106 experimental transitions, 48 972 being non-redundant, has been compiled through the analysis of 29 experimental sources, and a self-consistent network of 8558 rovibronic energy levels for the X, a, b, A, B, and C electronic states has been generated with the marvel algorithm covering rotational and vibrational quantum numbers J ≤ 69 and v ≤ 30 and energies up to 52 350.40 cm−1. No observed transitions connect to the $B\, {}^{3}\Sigma ^{-}$(v = 0) state which is required to model perturbations correctly, so we leave fitting the $B\, {}^3\Sigma ^-$ and $C\, {}^3\Pi$ state UV model to a future project. The SO line list is available at ExoMol from www.exomol.com.

Exploring the parameter space of an endohedral atom in a cylindrical cavity.

Endohedral fullerenes, or endofullerenes, are chemical systems of fullerene cages encapsulating single atoms or small molecules. These species provide an interesting challenge of Potential Energy Surface determination as examples of non-covalently bonded, bound systems. While the majority of studies focus on C60 as the encapsulating cage, introducing some anisotropy by using a different fullerene, e.g., C70 can unveil a double well potential along the unique axis. By approximating the potential as a pairwise Lennard-Jones (LJ) summation over the fixed C cage atoms, the parameter space of the Hamiltonian includes three tunable variables: (M, ɛ, σ) representing the mass of the trapped species, the LJ energy, and length scales respectively. Fixing the mass and allowing the others to vary can imitate the potentials of endohedral species trapped in more elongated fullerenes. We choose to explore the LJ parameter space of an endohedral atom in C70 with ɛ ∈ [20, 150 cm-1], and σ ∈ [2.85, 3.05 Å]. As the barrier height and positions of these wells vary between [1, 264 cm-1] and [0.35, 0.85 Å] respectively, using a 3D direct product basis of 1D harmonic oscillator (HO) wavefunctions centred at the origin where there is a local maximum is unphysical. Instead we propose the use of a non-orthogonal basis set, using 1D HO wavefunctions centred in each minimum and compare this to other choices. The ground state energy of the X@C70 is tracked across the LJ parameter space, along with its corresponding nuclear translational wavefunctions. A classification of the wavefunction characteristics, namely the prolateness and "peanut-likeness" based on its statistical moments is also proposed. Excited states of longer fullerenes are assigned quantum numbers, and the fundamental transitions of Ne@C70 are tracked across the parameter space.

Study of I=0 bottomonium bound states and resonances in S , P , D , and F waves with lattice QCD static-static-light-light potentials

In this paper we study $I = 0$ bottomonium in $S$, $P$, $D$ and $F$ waves considering five coupled channels, one confined quarkonium and four open $B^{(*)} \bar B^{(*)}$ and $B_s^{(*)} \bar B_s^{(*)}$ meson-meson channels. To this end we use and extend a recently developed novel approach utilizing lattice QCD string breaking potentials for the study of quarkonium bound states and resonances. This approach is based on the Born Oppenheimer approximation and the unitary emergent wave method and allows to compute the poles of the $\mbox{T}$ matrix. We compare our results to existing experimental results for $I = 0$ bottomonium and discuss masses, decay widths and the assignment of angular momentum quantum numbers. Moreover, we determine the quarkonium and meson-meson composition of these states to clarify, which of them are ordinary quarkonium, and which of them should rather be interpreted as tetraquarks.

Systematic analysis of strange single heavy baryons and * *Supported by the National Natural Science Foundation of China (11675265, 12175068), the Continuous Basic Scientific Research Project (WDJC-2019-13), the Leading Innovation Project (LC 192209000701) and the Central Government Guidance Funds for Local Scientific and Technological Development of China (Guike ZY22096024)

Motivated by the experimental progress in the study of heavy baryons, we investigate the mass spectra of strange single heavy baryons in the λ-mode, using the relativistic quark model and the infinitesimally shifted Gaussian basis function method. We show that experimental results are well captured using the predicted masses. The root mean square radii and radial probability density distributions of the wave functions are analyzed in detail. Meanwhile, the mass spectra allow us to successfully construct the Regge trajectories in the plane. We also preliminarily assign quantum numbers to the recently observed baryons, including , , , , , , , , , , , and . Finally, the spectral structure of strange single heavy baryons is discussed. Accordingly, we predict several new baryons that may be observed in forthcoming experiments.

Quantum number assignments of light strange baryons in Regge phenomenology

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,M2) and (n,M2) 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 JP assignments.

Novel machine-learning method for spin classification of neutron resonances

The performance of nuclear reactors and other nuclear systems depends on a precise understanding of the neutron interaction cross sections for materials used in these systems. These cross sections exhibit resonant structure whose shape is determined in part by the angular-momentum quantum numbers of the resonances. The correct assignment of the quantum numbers of neutron resonances is, therefore, paramount. In this project, we apply machine learning to automate the quantum number assignments using only the resonances' energies and widths and not relying on detailed transmission or capture measurements. The classifier used for quantum number assignment is trained using stochastically generated resonance sequences whose distributions mimic those of real data. We explore the use of several physics-motivated features for training our classifier. These features amount to out-of-distribution tests of a given resonance's widths and resonance-pair spacings. We pay special attention to situations where either capture widths cannot be trusted for classification purposes or where there is insufficient information to classify resonances by the total spin $J$. We demonstrate the efficacy of our classification approach using simulated and actual $^{52}\mathrm{Cr}$ resonance data.

Systematic study of one-loop realizations of d = 7 long-range 0νββ decay operators

We study the systematical one-loop decomposition of the dimension-7 long-range 0νββ decay operators. We find that there are 3 genuine one-loop topologies and 8 diagrams. The procedure to determine the SM quantum number assignments for both internal and external fields is presented. The Majorana neutrino mass in long-range 0νββ models is discussed. We also present a one-loop 0νββ decay model which produces Majorana neutrino mass at three-loop level. The phenomenological predictions for light neutrino mass and 0νββ decay half-life time including both mass mechanism and long-range contribution are studied.

Strong decay widths and mass spectra of charmed baryons

The total decay widths of the charmed baryons are calculated by means of the $^{3}{P}_{0}$ model. Our calculations consider in the final states: the charmed baryon-(vector/pseudoscalar) meson pairs and the (octet/decuplet) baryon-(pseudoscalar/vector) charmed meson pairs, within a constituent quark model. Furthermore, we calculate the masses of the charmed baryon ground states and their excitations up to the $D$-wave in a constituent quark model both in the three-quark and in the quark-diquark schemes, utilizing a Hamiltonian model based on a harmonic oscillator potential plus a mass splitting term that encodes the spin, spin-orbit, isospin, and flavor interactions. The parameters of the Hamiltonian model are fitted to the experimental data of the charmed baryon masses and decay widths. As the experimental uncertainties of the data affect the fitted model parameters, we have thoroughly propagated these uncertainties into our predicted charmed baryon masses and decay widths via a Monte Carlo bootstrap approach, which is often absent in other theoretical studies on this subject. Our quantum number assignments and predictions of the masses and strong partial decay widths are in reasonable agreement with the available data. Thus, our results show the ability to guide future measurements in LHCb, Belle and Belle II experiments. Finally, the appendices provide some details of our calculations, in which we include the flavor coupling coefficients, which are useful for further theoretical investigations.

Molecular interpretation of X(3960) as D_s^+ D_s^- state

We study D_s^+ D_s^- and D bar{D} states assuming that they are hadronic molecules with J^{PC}=0^{++} quantum number. We use two-point QCD sum rule formalism and extract the mass and decay constant values of these states. We take into account contributions of various quark, gluon, and mixed vacuum condensates up to dimension eight. The extracted mass and decay constant values of D bar{D} and D_s^+ D_s^- states read as M_{D bar{D}} = 3795^{+85}_{-82}~{textrm{MeV}} , f_{D bar{D}} = 1.70^{+0.33}_{-0.29} times 10^{-2} ~{textrm{GeV}}^5, and M_{D_s^+ D_s^-} = 3983^{+93}_{-88} ~{textrm{MeV}}, f_{D_s^+ D_s^-} = 2.52^{+0.64}_{-0.54} times 10^{-2} ~{textrm{GeV}}^5, respectively. The predicted mass of D_s^+ D_s^- state is in good agreement with the recent LHCb observation and supports quantum number and molecular picture assignments. A possible observation of D bar{D} state would help for establishing the lowest four-quark state in charmonium sector.

Experimental study of the 3Πg3 and 4Σg+3 states of the rubidium dimer

This paper reports a high-resolution experimental study of the $3^{3}\mathrm{\ensuremath{\Pi}}_{g}$ and $4^{3}\mathrm{\ensuremath{\Sigma}}_{g}^{+}$ electronic states of the $^{85}\mathrm{Rb}_{2}$ dimer. In the experiment, rovibrational levels of the two electronic states were probed using the perturbation facilitated optical-optical double resonance technique by exciting $^{85}\mathrm{Rb}_{2}$ molecules from thermally populated levels of the ground $X^{1}\mathrm{\ensuremath{\Sigma}}_{g}^{+}$ state through intermediate levels of the mixed $A^{1}\mathrm{\ensuremath{\Sigma}}_{u}^{+}\ensuremath{\sim}b^{3}\mathrm{\ensuremath{\Pi}}_{u}$ electronic states. The resonances of the probe laser were observed by detecting the laser induced fluorescence from the target states to the $a^{3}\mathrm{\ensuremath{\Sigma}}_{u}^{+}$ triplet ground state. In addition, to confirm the triplet character as well as the vibrational quantum number assignment of the states, for selected resonances the fluorescence to the $a^{3}\mathrm{\ensuremath{\Sigma}}_{u}^{+}$ state was resolved and bound-free spectra were recorded. From the observed term values for each state potential-energy curves were constructed using the Rydberg-Klein-Rees method.

Precision measurement of quasi-bound resonances in H2 and the H + H scattering length

Quasi-bound resonances of are produced via two-photon photolysis of S molecules as reactive intermediates or transition states and detected before decay of the parent molecule into three separate atoms. As was previously reported [K. F. Lai et al., Phys. Rev. Lett. 127, 183001 (2021)] four centrifugally bound quantum resonances with lifetimes of multiple μs, lying energetically above the dissociation limit of the electronic ground state of , were observed as , , , and , while also the short-lived ( ns) quasi-bound resonance was probed. The present paper gives a detailed account on the identification of the quasi-bound or shape resonances, based on laser detection via - two-photon transitions, and their strongly enhanced Franck-Condon factors due to the shifting of the wave function density to large internuclear separation. In addition, the assignment of the rotational quantum number is verified by subsequent multi-step laser excitation into autoionisation continuum resonances. Existing frameworks of full-fledged ab initio computations for the bound region in , including Born-Oppenheimer, adiabatic, non-adiabatic, relativistic and quantum-electrodynamic contributions, are extended into the energetic range above the dissociation energy. These comprehensive calculations are compared to the accurate measurements of energies of quasi-bound resonances, finding excellent agreement. They show that the quasi-bound states are in particular sensitive to non-adiabatic contributions to the potential energy. From the potential energy curve and the correction terms, now tested at high accuracy over a wide range of energies and internuclear separations, the s-wave scattering length for singlet H+H scattering is determined at . It is for the first time that such an accurate value for a scattering length is determined based on fully ab initio methods including effects of adiabatic, non-adiabatic, relativistic and QED with contributions up to .

Magnetic Feshbach resonances in collisions of 23Na40K with 40K

We present measurements of more than 80 magnetic Feshbach resonances in collisions of ultracold 23Na40K with 40K. We assign quantum numbers to a group of low-field resonances and show that they are probably due to long-range states of the triatomic complex in which the quantum numbers of the separated atom and molecule are approximately preserved. The resonant states are not members of chaotic bath of short-range states. Similar resonances are expected to be a common feature of alkali-metal diatom + atom systems.

Study on Zcs and excited Bs0 states in the chiral quark model

Stimulated by the newly observed charged hidden-charm state ${Z}_{cs}(3985{)}^{\ensuremath{-}}$ by BESIII Collaboration, ${Z}_{cs}(4000{)}^{+}$, ${Z}_{cs}(4220{)}^{+}$ and the excited ${B}_{s}^{0}$ states by LHCb Collaboration, a full calculation including masses, decay widths, and the inner structures of the states has emerged in the chiral quark model. For ${Z}_{cs}$ states, we assign quantum numbers $I({J}^{P})=\frac{1}{2}({1}^{+})$ and quark composition $c\overline{c}s\overline{u}$ according to the experiment. For ${B}_{s}^{0}$ states, systematically, investigations are performed with $I({J}^{P})=0({0}^{+}),0({1}^{+}),0({2}^{+})$ in both two-body $b\overline{s}$ and four-body $b\overline{s}q\overline{q}$ ($q=u$ or $d$) systems. Each tetraquark calculation takes all structures including meson-meson, diquark-antidiquark, and all possible color configurations into account. Among the numerical techniques to solve the two-body and four-body Schr\"odinger equation, the spatial wave functions are expanded in series of Gaussian basis functions for high precision, which is the way Gaussian expansion method (GEM) so called. Our results indicate that the low-lying states of the four-quark system are all higher than the corresponding thresholds either for $c\overline{c}s\overline{u}$ or for $b\overline{s}q\overline{q}$ systems. With the help of the real scaling method, we found two molecular resonance states with masses of 4023 and 4042 MeV for the $c\overline{c}s\overline{u}$ system. The state $c\overline{c}s\overline{u}(4042)$ has a close mass and decay width with the recent observed state ${Z}_{cs}(3985{)}^{\ensuremath{-}}$. For the $b\overline{s}q\overline{q}$ system with $J=0$, some resonance states are also found. The newly observed excited ${B}_{s}^{0}$ states can be accommodated in the chiral quark model as $2S$ or $1D$ states, and the mixing with four-quark states also needs to be considered.

Synthesis of ab initio and effective Hamiltonian line lists for ozone

A synthetic line list for the ozone molecule is presented. Variational calculation using the semi-empirical potential energy surface (PES) and ab initio dipole moment surface (DMS) produce very accurate values of line intensities, but give line positions far away from their experimental values. Furthermore assignment of approximate rotational and vibrational quantum numbers are missing from variationally calculated line list. Effective Hamiltonian calculations are complimentary to ab initio line lists in these properties giving excellent value of line positions, close to experimental ones, and a full set of quantum numbers assignment. The synthesis of both these qualities in one line list is highly desirable. Here a synthetic line list for 16O3 is presented. The method of corrections of distorted intensities in variational linelist with ab initio DMS due to the artificial intensity stealing is developed and applied. Comparison of the synthetic line list with all major published line lists and available experimental data is given. The calculated line intensities agree to within experimental error for most bands for which accurate measurements are available.

Can the newly reported Pcs(4459) be a strange hidden-charm ΞcD¯* molecular pentaquark?

Stimulated by the $P_{cs}(4459)$ reported by the LHCb Collaboration, we perform a single $\Xi_c\bar{D}^*$ channel and a coupled $\Xi_c\bar{D}^*/\Xi_c^*\bar{D}/\Xi_c^{\prime}\bar{D}^*/\Xi_c^*\bar{D}^*$ channel analysis by using a one-boson-exchange model. Our results indicate that the newly $P_{cs}(4459)$ cannot be a pure $\Xi_c\bar{D}^*$ molecular state, but a coupled $\Xi_c\bar{D}^*/\Xi_c^*\bar{D}/\Xi_c^{\prime}\bar{D}^*/\Xi_c^*\bar{D}^*$ bound state with $I(J^P)=0(3/2^-)$, where the $\Xi_c\bar{D}^*$ and $\Xi_c^*\bar{D}$ components are dominant. Meanwhile, we find the interactions from the $\Xi_c^{\prime}\bar{D}^*$ system with $0(1/2^-)$, the $\Xi_c^{*}\bar{D}$ system with $1(3/2^-)$, and the $\Xi_c^{*}\bar{D}^*$ system with $1(1/2^-)$ are strongly attractive, where one can expect possible strange hidden-charm molecular or resonant structures near the these thresholds with the assigned quantum numbers.

β -decay rates of Rh115,117 into Pd115,117 isotopes in the microscopic interacting boson-fermion model

The structure of odd-$A$ $^{(115,117)}$Rh and $^{(115,117)}$Pd isotopes is studied by means of the neutron-proton Interacting Boson-Fermion Model (IBFM-2). $J^P = \frac{1}{2}^+$ quantum number assignment for the $^{(115,117)}$Pd ground-states is critically discussed and the predicted energy levels are compared to the existing experimental data. The resulting nuclear wave functions are used to compute the $\beta$-decay $ft$ values of the transitions from $^{(115,117)}$Rh to $^{(115,117)}$Pd in the microscopic IBFM-2 and the results compared with the data.

Field-free, Stark, and Zeeman spectroscopy of the Ã2Π1/2−X̃2Σ+ transition of ytterbium monohydroxide

The 000A2Π1/2−X2Σ+, 110A2Π1/2−X2Σ+, and 101A2Π1/2−X2Σ+ bands of an internally cold molecular beam sample of ytterbium monohydroxide, YbOH, have been recorded at the near natural linewidth limit and analyzed to determine the fine structure parameters. Numerous lines in the 000A2Π1/2−X2Σ+ band associated with the lowest rotational levels were recorded in the presence of a static electric field and analyzed to determine the magnitude of the molecular frame permanent electric dipole moment, |μel|, for the X2Σ+(0,0,0) and A2Π1/2(0,0,0) states of 1.9(2) and 0.43(10) D, respectively. An electrostatic polarizability model is used to predict the μel for the X2Σ+(0,0,0) state. The 000A2Π1/2−X2Σ+ band is recorded in the presence of a weak static magnetic field to observe the electric dipole allowed transitions having ΔJ=−2, which are used to assist in the rotational quantum number assignment and confirm the identity of the excited state. An expression for the A2Π1/2(0,0,0) magnetic g factor is derived and shown to correctly model the observed magnetic tuning. A comparison with YbF is made and implications for the use of YbOH as a venue for symmetry violation measurements are discussed.

Universal thermodynamics of a trapped Fermi gas in the superfluid regime: the role of the Pauli principle

Understanding the universal behavior of strongly-interacting systems of particles has been a major goal in multiple fields of physics from atomic physics to cosmology. Using a recently introduced manybody perturbation formalism for fermions which uses group theoretic and graphical techniques to solve the N-body problem, I study the thermodynamic behavior of the unitary regime for a trapped Fermi gas and investigate the role of the Pauli principle in the emergence of collective behavior, specifically superfluidity at ultralow temperatures. The method, which is called symmetry invariant perturbation theory, has no adjustable parameters and currently offers a solution to the manybody Schrodinger equation through first order in inverse dimensionality exactly. The solution at first order defines collective coordinates in terms of five types of N-body normal modes, identified as symmetric stretch, symmetric bend, single particle angular excitation, single particle radial excitation and phonon. A correspondence is established ‘on paper’ that enforces the Pauli principle through the assignment of specific normal mode quantum numbers. Applied at ultracold temperatures, this normal mode assignment yields occupation only in an extremely low frequency N-body phonon mode. A single particle radial excitation mode at a much higher frequency creates a gap that stabilizes the superfluidity at low temperatures. This radial excitation involves excitation of a single particle out of the synced motion of the phonon mode, rather than the breaking of a fermion pair. Coupled with the corresponding values for the energies at unitarity obtained by this manybody calculation, I obtain good agreement with experimental thermodynamic results. In particular, the lambda transition in the specific heat is clearly seen. Based on these findings, I propose a mechanism for the emergence of superfluidity at ultralow temperatures in this unitary regime that is driven by quantum statistics and the enforcement of the Pauli principle through the selection of normal modes. My results for the calculated thermodynamic quantities suggest that the emergence of some collective behaviors in macroscopic systems is due to the Pauli principle producing manybody pairing and the resulting macroscopic occupation of an N-body phonon mode.

Spectrum of Field-Ionized Triplet Gerade Rydberg States of H2 and Comparison to Multichannel Quantum-Defect Theory.

A spectrum of field-ionized triplet Rydberg states of gerade symmetry H2 has been measured, excited from the υ″ = 0, N″ = 1-3 rovibrational levels of the metastable c3Πu-2pπ state in a 6 keV fast molecular beam. The field-ionized spectrum is kinetic energy labeled in order to separate it from the well-studied υ+ ≥ 1 autoionization spectrum. The spectrum consists of both ns and nd Rydberg series with n between 10 and 28 converging to the υ+ = 0, N+ = 1-3 levels of the X+ 2Σg+ ground state of H2+. Transitions with changes in vibration and/or rotation are also identified. The spectral positions of 59 transitions in the field ionization spectrum are identified and assigned quantum numbers using the predictions of multichannel quantum-defect theory (MQDT). The transition energies and subsequent effective quantum defects are compared between the experiment and theory. Most of the observed transitions, within the experimental uncertainty of 0.2 cm-1, agree with the energies predicted by MQDT.