Spin Parity Research Articles

Spin Parity of Spiral Galaxies. III. Dipole Analysis of the Distribution of SDSS Spirals with 3D Random Walk Simulations

Abstract Observation has not yet determined whether the distribution of spin vectors of galaxies is truly random. It is unclear whether is there any large-scale symmetry-breaking in the distribution of the vorticity field in the universe. Here, we present a formulation to evaluate the dipole component D max of the observed spin distribution, whose statistical significance σ D can be calibrated by the expected amplitude for 3D random walk (random flight) simulations. We apply this formulation to evaluate the dipole component in the distribution of Sloan Digital Sky Survey (SDSS) spirals. Shamir published a catalog of spiral galaxies from the SDSS DR8, classifying them with his pattern recognition tool into clockwise and counterclockwise (Z-spiral and S-spiral, respectively). He found significant photometric asymmetry in their distribution. We have confirmed that this sample provides dipole asymmetry up to a level of σ D = 4.00. However, we also found that the catalog contains a significant number of multiple entries of the same galaxies. After removing the duplicated entries, the number of samples shrunk considerably to 45%. The actual dipole asymmetry observed for the “cleaned” catalog is quite modest, σ D = 0.29. We conclude that SDSS data alone do not support the presence of a large-scale symmetry-breaking in the spin vector distribution of galaxies in the local universe. The data are compatible with a random distribution.

Investigation of the alignment mechanism and loss of collectivity in Pm135

High-spin excited states of $^{135}\mathrm{Pm}$ have been investigated using the $^{107}\mathrm{Ag}(^{32}\mathrm{S}$, $2p2n$) reaction at 145-MeV beam energy. Three negative-parity bands have been investigated up to $\ensuremath{\sim}9.0\ensuremath{-}$, $7.6\ensuremath{-}$, and $6.9\ensuremath{-}\mathrm{MeV}$ excitation energies with spin parities $(55/{2}^{\ensuremath{-}})$, $(49/{2}^{\ensuremath{-}})$, and $(47/{2}^{\ensuremath{-}})\phantom{\rule{4pt}{0ex}}\ensuremath{\hbar}$, respectively. The experimental results have been interpreted using the triaxial projected shell model. It is shown that the observation of the parallel band structures can be explained in terms of crossing of two $s$ bands with the yrast band, which is a rare phenomenon for an odd-$A$ nucleus. Further, the lifetimes of levels in yrast band have been extracted using Doppler shift attenuation method. The evaluated $B(E2)$ values of yrast states show the loss of collectivity at higher spin, attributed to the alignment process.

Mixing angles between the tetraquark states with two heavy quarks within QCDsum rules

LHCb collaboration has recently announced the observation of a doubly charmed tetraquark $T_{cc \bar{u} \bar{d}}^+$ state with spin parity $J^P = 1^+$. This exotic state can be explained as a molecular state with small binding energy. According to conventional quark model, both $D^+ D^{0\ast}$ and $(D^0 D^{+\ast})$ multiquark states are expected to have the same mass and flavor in the exact $SU(3)$ symmetry. However, since the quark masses are different, $SU(3) (SU(2))$ symmetry is violated; hence, the mass and flavor eigenstates do not coincide. The mass eigenstates can be represented as a linear combination of the flavor eigenstates, which is characterized by the mixing angle $\theta$. In the present work, the possible mixing angles between the $T_{cc}$ states are calculated. Moreover, the analyses are extended for all the possible tetraquarks scenarios with two heavy and two light quarks within the molecular picture although those states have not been observed yet. Our prediction on mixing angle between doubly charmed tetraquark states shows that $SU(3)$ symmetry breaking is around $7\%$ maximally.

Theoretical interpretation of Ξc(2970)

The open charm strong decay widths and certain ratio of branching fractions of a charmed strange baryon ${\mathrm{\ensuremath{\Xi}}}_{c}(2970)$ are calculated in a $^{3}{P}_{0}$ model. The results are compatible with the latest experimental data. The theoretical ratio of decay branching fractions $R=\mathcal{B}[{\mathrm{\ensuremath{\Xi}}}_{c}(2970{)}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}(2645{)}^{0}{\ensuremath{\pi}}^{+}]/\mathcal{B}[{\mathrm{\ensuremath{\Xi}}}_{c}(2970{)}^{+}\ensuremath{\rightarrow}\phantom{\rule{0ex}{0ex}}{\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}0}{\ensuremath{\pi}}^{+}]\ensuremath{\approx}1.0$. The spin parity ${J}^{P}=1/{2}^{+}$ and $3/{2}^{+}$ for different assignments are analyzed. From the results of our calculation, ${\mathrm{\ensuremath{\Xi}}}_{c}(2970)$ can be interpreted as a $2S$-wave state with ${J}^{P}({s}_{l})=1/{2}^{+}(0)$. The distinctions between the $2S$-wave ${n}_{\ensuremath{\rho}}$- and ${n}_{\ensuremath{\lambda}}$-excitation states and between states with ${s}_{l}=0$ and ${s}_{l}=1$ and between states with total spin $1/2$ and $3/2({s}_{l}=1)$ are also discussed.

Hidden-bottom molecular states from varSigma ^{(*)}_bB^{(*)}-varLambda _bB^{(*)} interaction

In this work, we study possible hidden-bottom molecular pentaquarks P_b from coupled-channel varSigma ^{(*)}_bB^{(*)}-varLambda _bB^{(*)} interaction in the quasipotential Bethe-Salpeter equation approach. In isodoublet sector with I=1/2, with the same reasonable parameters the interaction produces seven molecular states, a state near varSigma _bB threshold with spin parity J^P=1/2^-, a state near varSigma ^*_bB threshold with 3/2^-, two states near varSigma _bB^* threshold with 1/2^- and 3/2^-, and three states near varSigma _b^*B^* threshold with 1/2^-, 3/2^-, and 5/2^-. The results suggest that three states near varSigma _b^* B^* threshold and two states near varSigma _b B^* threshold are very close, respectively, which may be difficult to distinguish in experiment without partial wave analysis. Compared with the hidden-charm pentaquark, the P_b states are relatively narrow with widths at an order of magnitude of 1 MeV or smaller. The importance of each channel considered is also discussed, and it is found that the varLambda _b B^* channel provides important contribution for the widths of those states. In isoquartet sector with I=3/2, cutoff should be considerably enlarged to achieve bound states from the interaction, which makes the existence of such states unreliable. The results in the current work are helpful for searching for hidden-bottom molecular pentaquarks in future experiments, such as the COMPASS, J-PARC, and the Electron Ion Collider in China (EicC).

Synthesis on Heavy Higgs from the Standard Model to 2HDM and Beyond

In the context of particle physics, within the ATLAS and CMS experiments at large hadron collider (LHC), this work presents the discussion of the discovery of a particle compatible with the Higgs boson by the combination of several decay channels, with a mass of the order of 125.5 GeV. With increased statistics, that is the full set of data collected by the ATLAS and CMS experiments at LHC ( s1/2 = 7GeV and s1/2 = 8GeV ), the particle is also discovered individually in the channel h-->γγ with an observed significance of 5.2σ and 4.7σ, respectively. The analysis dedicated to the measurement of the mass mh and signal strength μ which is defined as the ratio of σ(pp --> h) X Br(h-->X) normalized to its Standard Model where X = WW*; ZZ*; γγ ; gg; ff. The combined results in h-->γγ channel gave the measurements: mh = 125:36 ± 0:37Gev, (μ = 1:17 ± 0:3) and the constraint on the width Γ(h) of the Higgs decay of 4.07 MeV at 95%CL. The spin study rejects the hypothesis of spin 2 at 99 %CL. The odd parity (spin parity 0- state) is excluded at more than 98%CL. Within the theoretical and experimental uncertainties accessible at the time of the analysis, all results: channels showing the excess with respect to the background-only hypothesis, measured mass and signal strength, couplings, quantum numbers (JPC), production modes, total and differential cross-sections, are compatible with the Standard Model Higgs boson at 95%CL. Although the Standard Model is one of the theories that have experienced the greatest number of successes to date, it is imperfect. The inability of this model to describe certain phenomena seems to suggest that it is only an approximation of a more general theory. Models beyond the Standard Model, such as 2HDM, MSSM or NMSSM, can compensate some of its limitations and postulate the existence of additional Higgs bosons.

X(2239) and as hidden-strange molecular states from interaction * *Supported by the National Natural Science Foundation of China (11675228, 11775050, 61871124), the Fundamental Research Funds for the Central Universities, the national defense Pre-Research foundation of China, by State Key Laboratory of Acoustics, Chinese Academy of Sciences (SKLA201604), Science and Technology on Sonar Laboratory, the Stable Supporting Fund of Acoustic Science

In this work, we propose the possible assignment of the newly observed , as well as , as a molecular state from the interaction of a baryon and an antibaryon . With the help of effective Lagrangians, the interaction is described within the one-boson-exchange model with , , , , and exchanges considered. After inserting the potential kernel into the quasipotential Bethe-Salpeter equation, the bound states from the interaction can be studied by searching for the pole of the scattering amplitude. Two loosely bound states with spin parities and appear near the threshold with almost the same parameter. The state can be assigned to observed at BESIII, which is very close to the threshold. The scalar meson can be interpreted as a state from the interaction. The annihilation effect is also discussed through a coupled-channel calculation plus a phenomenological optical potential. It provides large widths to two bound states produced from the interaction. The mass of the state is slightly larger than the mass of the state after including the annihilation effect, which is consistent with our assignment of these two states as and , respectively. The results suggest that further investigation is required to understand the structures near the threshold, such as , , and .

Spin-Orbit-Parity-Coupled Superconductivity in Topological Monolayer WTe_{2}.

Recent experiments reported gate-induced superconductivity in the monolayer 1T^{'}-WTe_{2} which is a two-dimensional topological insulator in its normal state. The in-plane upper critical field B_{c2} is found to exceed the conventional Pauli paramagnetic limit B_{p} by one to three times. The enhancement cannot be explained by conventional spin-orbit coupling which vanishes due to inversion symmetry. In this Letter, we unveil some distinctive superconducting properties of centrosymmetric 1T^{'}-WTe_{2} which arise from the coupling of spin, momentum and band parity degrees of freedom. As a result of this spin-orbit-parity coupling (SOPC): (i)there is a first-order superconductor-metal transition at B_{c2} that is much higher than the Pauli paramagnetic limit B_{p}, (ii)spin-susceptibility is anisotropic with respect to in-plane directions and can result in possible anisotropic B_{c2}, and (iii)the B_{c2} exhibits a strong gate dependence as the spin-orbit-parity coupling is significant only near the topological band crossing points. The importance of SOPC on the topologically nontrivial inter-orbital pairing phase is also discussed. Our theory generally applies to centrosymmetric materials with topological band inversions.

Theoretical Calculation of the IBM1 Parameters and Band Crossing in Even Cerium Isotopes

An extended microscopic version of the interacting-boson model is developed. The properties of yrast-band states in even cerium isotopes up to the spin–parity of $$I^{\pi}=18^{+}$$ are calculated on the basis of this model. These spin values include those at which band crossing occurs. The model parameters are calculated on the basis of employing an average spherical potential and residual multipole forces. An extension of the model is accomplished via taking into account high-spin quasiparticle pairs, whereby a satisfactory description of energies and $$B(E\text{2})$$ values was obtained without introducing effective charges. The present investigation is a continuation of a similar analysis of the properties of low-lying collective states in even xenon and barium isotopes.

Phase-space elementary information content of confined Dirac spinors

Reporting on the Wigner formalism for describing Dirac spinor structures through a covariant phase-space formulation, the quantum information quantifiers for purity and mutual information involving spin–parity (discrete) and position–momentum (continuous) degrees of freedom are consistently obtained. For Dirac spinor Wigner operators decomposed into Poincaré classes of $$\mathrm{SU}(2)\otimes \mathrm{SU}(2)$$ spinor couplings, a definitive expression for quantum purity is identified in a twofold way: firstly in terms of phase-space positively defined quantities and secondly in terms of the spin–parity traced-out-associated density matrix in the position coordinate representation, both derived from the original Lorentz-covariant phase-space Wigner representation. Naturally, such a structure supports the computation of relative (linear) entropies, respectively, associated with discrete (spin–parity) and continuous (position–momentum) degrees of freedom. The obtained theoretical tools are used for quantifying (relative) purities, mutual information as well as, by means of the quantum concurrence quantifier, the spin–parity quantum entanglement, for a charged fermion trapped by a uniform magnetic field which, by the way, has the phase-space structure completely described in terms of Laguerre polynomials associated with the quantized Landau levels. Our results can be read as the first step in the systematic computation of the elementary information content of Dirac-like systems exhibiting some kind of confining behavior.

Single particle entanglement of a massive relativistic particle: Dirac bispinors and spin 1/2 states

In this paper we study the single particle entanglement induced by a Lorentz boost. We described the particle as a solution of the free Dirac equation, a Dirac bispinor, and compare the induced momentum-spin entanglement with the result obtained in the widely considered framework of relativistic spin 1/2 states. The spin linear entropy for both approaches agree in the ultra relativistic limit. We also verify that the spin-momentum entanglement differers from the spin entropy for the bispinorial case, indicating a true multipartite entanglement involving the degrees of freedom of a Dirac bispinor state: momentum, spin and intrinsic parity. The fact that Dirac bispinors belongs to an irreducible representation of the complete Lorentz group, which also included parity as a symmetry, is the ultimate reason behind such non-trivial structure.

Pc pentaquarks with chiral tensor and quark dynamics

We investigate the hidden-charm pentaquarks as superpositions of $\Lambda_c \bar{D}^{(*)}$ and $\Sigma_c^{(*)} \bar{D}^{(*)}$ (isospin $I = 1/2$) meson-baryon channels coupled to a $uudc\bar{c}$ compact core by employing an interaction satisfying the heavy quark and chiral symmetries. Our model can consistently explain the masses and decay widths of $P_c^+(4312)$, $P_c^+(4440)$ and $P_c^+(4457)$ with the dominant components of $\Sigma_c \bar D$ and $\Sigma_c \bar D^\ast$ with spin parity assignments $J^P = 1/2^{-}, 3/2^{-}$ and $1/2^{-}$, respectively. We analyze basic properties of the $P_c$'s such as masses and decay widths, and find that the mass ordering is dominantly determined by the quark dynamics while the decay widths by the tensor force of the one-pion exchange.

QCD Kondo excitons

The quantum chromodynamics (QCD) Kondo effect is a quantum phenomenon in which heavy quarks ($c$, $b$) exist as impurity particles in quark matter composed of light quarks ($u$, $d$, $s$) at extremely high density. This is analogous to the famous Kondo effect in condensed matter physics. In the present paper, we show theoretically the existence of the "QCD Kondo excitons", i.e., the bound states of light quarks and heavy quarks, as the lowest-excitation modes above the ground state of the quark matter governed by the QCD Kondo effect. These are neutral for color and electric charges, similarly to the Kondo excitons in condensed matter, and they are new type of quasiparticles absent in the normal phase of quark matter. The QCD Kondo excitons have various masses and quantum numbers, i.e., flavors and spin parities (scalar, pseudoscalar, vector, and axialvector). The QCD Kondo excitons lead to the emergence of the neutral currents in transport phenomena, which are measurable in lattice QCD simulations. The study of the QCD Kondo excitons will provide us with understanding of new universal properties shared by quark matter and condensed matter.

Masses of light and heavy mesons and baryons: A unified picture

We compute masses of positive parity spin-$1/2$ and $3/2$ baryons composed of $u$, $d$, $s$, $c$ and $b$ quarks in a quark-diaquark picture. The mathematical foundation for this analysis is implemented through a symmetry-preserving Schwinger-Dyson equations treatment of a vector-vector contact interaction, which preserves key features of quantum chromodynamics, such as confinement, chiral symmetry breaking and low energy Goldberger-Treiman relations. This study requires a computation of diquark correlations containing these quarks which in turn are readily inferred from solving the Bethe-Salpeter equations of the corresponding mesons. Therefore, it serves as a unified formalism for a multitude of mesons and baryons. It builds on our previous works on the study of masses, decay constants and form factors of quarkonia and light mesons, employing the same model. We use two sets of parameters, one which remains exactly the same for both the light and heavy sector hadrons, and another where the coupling strength is allowed to evolve according to the available mass scales of quarks. Our results are in very good agreement with the existing experimental data as well as predictions of other theoretical approaches whenever comparison is possible.

Evening out the spin and charge parity to increase {T}_{c} in {{rm{Sr}}}_{2}{{rm{RuO}}}_{4}

Unconventional superconductivity in {{rm{Sr}}}_{2}{{rm{RuO}}}_{4} has been intensively studied for decades. However, the nature of pairing continues to be widely debated. Here we develop a detailed ab initio theory, coupling quasiparticle self-consistent GW approximation with dynamical mean field theory (DMFT), including both local and non-local correlations to address the subtle interplay among spin, charge and orbital degrees of freedom. We report that the superconducting instability has multiple triplet and singlet components. In the unstrained case the triplet eigenvalues are larger than the singlets. Under uniaxial strain, the triplet eigenvalues drop and the singlet components increase. This is concomitant with our observation of spin and charge fluctuations shifting closer to wave-vectors favoring singlet pairing. We identify a complex mechanism where charge fluctuations and spin fluctuations co-operate in the even-parity channel under strain leading to increment in critical temperature (Tc), thus proposing a novel mechanism for pushing the frontier of critical temperature (Tc) in unconventional ‘triplet’ superconductors.

Spin Parity of Spiral Galaxies. I. Corroborative Evidence for Trailing Spirals

Abstract Whether the spiral structure of galaxies is trailing or leading has been a subject of debate. We present a new spin parity catalog of 146 spiral galaxies that lists the following three pieces of information: whether the spiral structure observed on the sky is S-wise or Z-wise; which side of the minor axis of the galaxy is darker and redder, based on examination of Pan-STARRS and/or ESO/DSS2 red image archives; and which side of the major axis of the galaxy is approaching us based on the published literature. This paper confirms that all of the spiral galaxies in the catalog show a consistent relationship among these three parameters, without any confirmed counterexamples, which supports the generally accepted interpretation that all the spiral galaxies are trailing and that the darker/redder side of the galactic disk is closer to us. Although the results of this paper may not be surprising, they provide a rationale for analyzing the S/Z winding distribution of spiral galaxies, using the large and uniform image databases available now and in the near future, to study the spin vorticity distribution of galaxies in order to constrain the formation scenarios of galaxies and the large-scale structure of the universe.

Molecular states from varSigma ^{(*)}_c{bar{D}}^{(*)}-varLambda _c{bar{D}}^{(*)} interaction

In this work, we systemically investigate the molecular states from the varSigma ^{(*)}_c{bar{D}}^{(*)}-varLambda _c{bar{D}}^{(*)} interaction with the help of the Lagrangians with heavy quark and chiral symmetries in a quasipotential Bethe–Salpeter equation (qBSE) approach. The molecular states are produced from isodoublet (I=1/2) varSigma _c{bar{D}} interaction with spin parity J^P=1/2^- and varSigma _c{bar{D}}^* interaction with 1/2^- and 3/2^-. Their masses and widths are consistent with the P_c(4312), P_c(4440) and P_c(4457) observed at LHCb. The states, varSigma _c^*{bar{D}}^*(1/2^-), varSigma _c^*{bar{D}}^*(3/2^-) and varSigma ^*_c{bar{D}}(3/2^-), are also produced with the same parameters. The isodoublet varSigma _c^*{bar{D}}^* interaction with 5/2^-, as well as the isoquartet (I=3/2) varSigma _c{bar{D}}^* interactions with 1/2^- and 3/2^-, varSigma _c^*{bar{D}}^* interaction with 3/2^- and 5/2^-, are also attractive while very large cutoff is required to produce a molecular state. We also investigate the origin of the widths of these molecular states in the same qBSE frame. The varLambda {bar{D}}^* channel is dominant in the decays of the states, varSigma _c{bar{D}}^*(1/2^-), varSigma _c{bar{D}}^*(3/2^-), varSigma _c^*{bar{D}}(3/2^-), and varSigma _c{bar{D}}(1/2^-). The varSigma ^*_c{bar{D}}^*(1/2^-) state has large coupling to varSigma _c{bar{D}} channel while the varSigma _c{bar{D}}^*, varSigma ^*_c{bar{D}} and varLambda _c{bar{D}}^* channels provide similar contributions to the width of the varSigma ^*_c{bar{D}}^*(3/2^-) state. These results will be helpful to understand the current LHCb experimental results, and the three predicted states and the decay pattern of these hidden-charmed molecular pentaquarks can be checked in future experiments.

The study of the 12C states from the reaction 11B(3He, d)12C

The experiment was done to study 11B(3He, d)12C reaction with energy E(3He)=25 MeV. The aim of the experiment is to determine the properties of 12C states at high excitation energies and in particular to verify which of the conflicting spin-parity assignments of the 13.35 MeV state (2− or 4−) should be assigned. Behavior of the experimental angular distribution and also the DWBA calculation correspond to spin parity 4− for 13.35 MeV state.

Revisiting the role of n-p residual interaction and the Newby shift in K = 0 bands in the odd-odd actinides

We present an analysis of all the known $ K=0$ bands in the deformed odd-odd actinide nuclei using the two quasiparticle plus rotor model to obtain the values of Newby shift. The Newby shift so obtained is expected to be free from the Coriolis mixing effects. A total of 11 bands of 238Np, 234Pa, 240-244Am and 250Bk have been analyzed. We find that the staggering pattern in all the cases is properly reproduced. We also examine the validity of an empirical rule to obtain the sign of the Newby shift. We find that for the 8 cases when $ \Omega_{n} = \Omega_{p} \neq 1/2$, the rule predicts correct sign but the rule does not work in rest of the 3 cases when $ \Omega_{n} = \Omega_{p} =1/2$. As an important outcome of our study, we propose the spin parity assignments and level energies of the $ K=0$ and $ K=5$ G-M partner bands in 240Am, $ \{5/2[523]_{p}\otimes 5/2[622]_{n}\}$. We resolve the tentative nature of the assignments and present a unique level scheme. Also, we predict the band-head energy of $ K=0$ bands in four cases, namely three $ K=0$ bands of 238Np and one $ K=0$ band of 240Am , where the band-head energy is not known experimentally. These results may be useful for future experiments.

Theoretical studies on the fine structure of $$\upalpha $$ decay for even–odd and even–even isotopes of Cm, Cf, Fm and No nuclei

Using the cubic plus Yukawa plus exponential model (CYEM), half-lives of $$\upalpha $$ decay from the ground state of the parent nuclei to the ground state of the daughter nuclei and from the ground state to an excited state of the daughter nuclei have been systematically investigated for even–odd and even–even isotopes of Cm, Cf, Fm and No nuclei by incorporating centrifugal potential term, rotational energy term, deformation effects ( $$\beta _{2}$$ and $$\beta _{4}$$ ) of the parent and daughter nuclei and spin–parity effects. We have done our calculations by considering the Coulomb, centrifugal and Yukawa plus exponential potentials as an interacting barrier for separated fragments and the cubic potential for the overlapping region. The calculated half-lives are compared with the available data. Our results are found to be in good agreement with each other. The effect of the centrifugal potential on half-life was evaluated. The branching ratio, hindrance factor and standard deviation of half-lives from the ground state of the parent nuclei to the ground state of the daughter nuclei have been calculated.