Parity Partners Research Articles

Chiral symmetry breaking, chiral partners, and the [formula omitted] and [formula omitted] in medium

We clarify the concept of chiral partners. For a vector meson, the isospin-zero and hypercharge-zero state in the flavor octet mixes with the flavor singlet state. Since the flavor singlet vector meson does not have a chiral partner, the mixed ω and ϕ mesons will not have chiral partners. This means that even when chiral symmetry is restored, these mesons will not become degenerate with their corresponding parity partners. On the other hand, the K1 and K∗ mesons are chiral partners, and both have widths smaller than 100 MeV. Therefore, we emphasize that studying these mesons in environments where chiral symmetry is restored is particularly important for understanding the effect of chiral symmetry restoration on chiral partners and their masses.

Baryonic screening masses in QCD at high temperature

We compute the baryonic screening masses of the nucleon and of its negative parity partner in thermal QCD with Nf=3 massless quarks for a wide range of temperatures, from T∼1 GeV up to ∼160 GeV. The computation is performed by Monte Carlo simulations of lattice QCD with O(a)-improved Wilson fermions by exploiting a recently proposed strategy to study non-perturbatively QCD at very high temperature. Very large spatial extensions are considered in order to have negligible finite volume effects. For each temperature we have simulated 3 or 4 values of the lattice spacing, so as to perform the continuum limit extrapolation with confidence at a few permille accuracy. The degeneracy of the positive and negative parity-state screening masses, expected from Ward identities associated to non-singlet axial transformations, provides further evidence for the restoration of chiral symmetry in the high temperature regime of QCD. In the entire range of temperatures explored, the baryonic masses deviate from the free theory result, 3πT, by 4–8%. The contribution due to the interactions is clearly visible up to the highest temperature considered, and cannot be explained by the expected leading behavior in the QCD coupling constant g over the entire range of temperatures explored.

Analysis of Determinants of Risk Factors for Hepatitis B Incidence in Pregnant Women in Makassar City

Hepatitis B (HBV) infection in pregnant women has become a global concern because the most common transmission occurs worldwide, especially in endemic areas, namely mother-to-child transmission during the prepartum or perinatal period with the risk of contracting hepatitis B (HBV) infection. in children more than 90%. Quantitative research using observational analytic methods and case control study design was used to find risk factors. The sample size was obtained by means of "Total Sampling" for the case group as many as 45 respondents with a 1:1 ratio between the case and control groups. Data were processed and analyzed using chi-square test and logistic regression test. Statistical tests show that education level, parity, and sexual partners are risk factors for the incidence of hepatitis B in pregnant women. Meanwhile, age group and type of work are not risk factors for hepatitis B incidence in pregnant women. Education level, parity, and sexual partners are risk factors for hepatitis B incidence in pregnant women. Among all the risk factors found, sexual partners were the most at risk for the incidence of hepatitis B in pregnant women in Makassar City (p-value = 0.022; OR: 12.920; 95% CI: 1.440-115.894).

Anomaly-induced chiral mixing in cold and dense matter

We construct the spectral functions for light vector mesons at finite density and temperature in the presence of a novel mixing between parity partners, induced by baryon density via the Wess-Zumino-Witten action. As the main origin of in-medium broadening, a set of baryon resonances that strongly couple to the vector mesons and the modifications of kaons and anti-kaons due to the Kaplan-Nelson term are included. It is shown that the vector spectra, even with the broadening effects, exhibit sizable signatures of chiral symmetry restoration thanks to the chiral mixing depending on three-momenta carried by the vector mesons. Those spectral functions are used to calculate the integrated production rates of lepton pairs, and a proper binning in momenta and potential decrease in the vector-meson masses due to chiral symmetry restoration are discussed in quantifying the signatures.

Gluon string breaking and meson spectrum in the holographic Soft Wall model

We propose a general method for finding a string-like meson spectrum which is based on a certain condition for the breaking of closed gluon string. A model is constructed that successfully realizes the proposed method. The model is based on the holographic Soft Wall model for QCD and the use of the Wilson confinement criterion. We applied our approach to the vector and scalar cases and obtained numerical predictions for the intercepts of corresponding Regge like radial meson spectra. A good agreement is obtained both with the existing experimental data and with some other known phenomenological approaches. Remarkably, our closed string breaking condition has two branches. We argue that they should correspond to states of opposite parity. The Wilson confinement criterion leads then to a natural mass splitting between parity partners. The constructed model represents thus the first example of bottom-up holographic model in which the effects of chiral symmetry breaking can emerge automatically, i.e., without additional assumptions taken outside of the holographic approach.

Masses of hadrons in the chiral symmetry restored vacuum

We calculate the masses of the vector and axial-vector mesons as well as the nucleon and the delta resonance in the chiral symmetry restored vacuum. This is accomplished by separating the quark operators appearing in the QCD sum rules for these hadrons into the chiral symmetric and symmetry breaking parts depending on the contributions of the fermion zero modes. We then extract the vacuum expectation values of all the separated parts of the quark operators using the QCD sum rule relations for these hadrons with their vacuum masses and widths. By taking the chiral symmetry breaking parts to be zero while keeping the symmetric operators to their vacuum values, we obtain the chiral symmetric part of the hadron masses. We find that the masses of chiral partners, such as the $(\rho,a_1)$ and $(K^*,K_1)$, become degenerate to values between 500 and 600 MeV in the chiral symmetry restored vacuum, while parity partners $(\omega,f_1)$ that are chiral partners only in the limit where the disconnected diagrams are neglected remain non-degenerate with masses $(655,1060)$ MeV, respectively. The masses of the nucleon and the Delta are also found to reduce to about 500 and 600 MeV, respectively, in the chiral symmetric vacuum. This shows that while chiral symmetry breaking is responsible for the mass difference between chiral partner, both the meson and baryon retain non-trivial fraction of their masses in the chiral symmetry restored vacuum.

Mesons and baryons: Parity partners

We calculate masses of light and heavy mesons as well as baryons of negative parity containing $u,d,s,c$ and $b$ quarks. It is an extension of our previous work where we had studied the positive parity baryons. We adopt a quark-diquark picture of baryons where the diquarks are non-pointlike with a finite spatial extension. 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, axial vector Ward-Takahashi identity and low-energy Goldberger-Treiman relations. This treatment simultaneously describes mesons and provides attractive correlations for diquarks in the $\overline{3}$ representation. Employing this model, we compute the spectrum and masses of all spin-1/2 and spin-3/2 baryons of negative parity, supplementing our earlier evaluation of positive parity baryons, containing 1, 2 or 3 heavy quarks. In the process, we calculate masses of a multitude of mesons and corresponding diquarks. Wherever possible, we make comparisons of our results with known experimental observations as well as theoretical predictions of several models and approaches including lattice quantum chromodynamics, finding satisfactory agreement. We also make predictions for heavier states not yet observed in the experiment.

Dynamical diquarks in the $${\varvec{\gamma ^{(*)} p\rightarrow N(1535)\frac{1}{2}^-}}$$ transition

The $\gamma^{(\ast)}+p \to N(1535) \tfrac{1}{2}^-$ transition is studied using a symmetry-preserving regularisation of a vector$\,\otimes\,$vector contact interaction (SCI). The framework employs a Poincar\'e-covariant Faddeev equation to describe the initial and final state baryons as quark+di\-quark composites, wherein the diquark correlations are fully dynamical, interacting with the photon as allowed by their quantum numbers and continually engaging in breakup and recombination as required by the Faddeev kernel. The presence of such correlations owes largely to the mechanisms responsible for the emergence of hadron mass; and whereas the nucleon Faddeev amplitude is dominated by scalar and axial-vector diquark correlations, the amplitude of its parity partner, the $N(1535) \tfrac{1}{2}^-$, also contains sizeable pseudoscalar and vector diquark components. It is found that the $\gamma^{(\ast)}+p \to N(1535) \tfrac{1}{2}^-$ helicity amplitudes and related Dirac and Pauli form factors are keenly sensitive to the relative strengths of these diquark components in the baryon amplitudes, indicating that such resonance electrocouplings possess great sensitivity to baryon structural details. Whilst SCI analyses have their limitations, they also have the virtue of algebraic simplicity and a proven ability to reveal insights that can be used to inform more sophisticated studies in frameworks with closer ties to quantum chromodynamics.

Novel pentaquark picture for singly heavy baryons from chiral symmetry

We propose a new type of structure for singly heavy baryons of $Qqq\overline{q}q$ in addition to the conventional one of $Qqq$. Based on chiral symmetry of the light quarks, we show that the $Qqq\overline{q}q$ baryon offers a novel picture for heavy-quark spin-singlet and flavor-antisymmetric baryons. By making use of the effective Lagrangian approach, we find that ${\mathrm{\ensuremath{\Lambda}}}_{c}(2765)$ and ${\mathrm{\ensuremath{\Xi}}}_{c}(2967)$ are mostly $Qqq\overline{q}q$, while ${\mathrm{\ensuremath{\Lambda}}}_{c}(2286)$ and ${\mathrm{\ensuremath{\Xi}}}_{c}(2470)$ are mostly $Qqq$. The masses of negative-parity baryons are predicted. We also derive a sum rule and the extended Goldberger-Treiman relation that the masses of the baryons satisfy. Furthermore, a mass degeneracy of parity partners of the baryons with the restoration of chiral symmetry is discussed. These are the unique features that the conventional picture of radial excitation in the quark model does not accommodate. Our findings provide useful information not only for future experiments but also for future lattice simulations on diquarks.

Maternal Sociodemographic Factors and Antenatal Stress.

Antenatal stress has been associated with adverse birth outcomes such as fetal growth restriction, low birth weight, and preterm birth. Understanding key determinants of stress in a vulnerable pregnant population has the potential of informing development of targeted cost-effective interventions to mitigate against these adverse birth outcomes. We conducted a secondary analysis of data from 150 pregnant women attending antenatal care services at a rural referral hospital in Kenya. The participants completed a sociodemographic and clinical questionnaire, the Cohen’s Perceived Stress Scale (PSS) and gave a hair sample for cortisol and cortisone analysis. The association between selected sociodemographic predictors (age, parity, marital status, maternal education, household income, polygyny, and intimate partner violence) and outcomes (hair cortisol, hair cortisone, and PSS score) was examined using univariate, bivariate and multivariate models. We found a negative association between PSS scores and household income (β = −2.40, p = 0.016, 95% CI = −4.36, −0.45). There was a positive association of the ratio of hair cortisone to cortisol with Adolescent age group (β = 0.64, p = 0.031, 95% CI = 0.06, 1.22), and a negative association with Cohabitation (β = −1.21, p = 0.009, 95% CI = −2.11, −0.31). We conclude that household income influenced psychological stress in pregnancy. Adolescence and cohabitation may have an influence on biological stress, but the nature of this effect is unclear.

Parity partner bands in 163Lu: A novel approach for describing the negative parity states from a triaxial super-deformed band

The wobbling spectrum of [Formula: see text]Lu is described through a novel approach, starting from a triaxial rotor model within a semi-classical picture, and obtaining a new set of equations for all four rotational bands that have wobbling character. Redefining the band structure in the present model is done by adopting the concepts of Signature Partner Bands and Parity Partner Bands. Indeed, describing a wobbling spectrum in an even–odd nucleus through signature and parity quantum numbers is an inedited interpretation of the triaxial super-deformed bands.

To a Question of Social Dynamics of Migration Processes: World and Russian Transformations

The conceptual basis of the article is based on the following position: in modern conditions of innovative development of social systems (both international and national), the structure of migration processes loses the quality of the first position, migration becomes an integral part of its everyday life. The analysis of the social dynamics of migration processes, the strategies of migrants against the background of intensified risks and uncertainty in the receiving side is of particular relevance. The article presents statistical data of the Population Division of the UN international organization – a member of the Global Group on Migration, on the ratio of the number of migrants and the total population on a global scale, as well as the number and share of immigrants in gender and geographic context, a review of scientific foreign and domestic literature is carried out. which reflects the assessments of the features of horizontal movements in recent decades, describes the behavioral strategies of migrants, representatives of a foreign cultural environment. The author’s theoretical multifactor model is presented, aimed at identifying promising areas for further research, reflecting the escalation of the impact of migration flows and the increase in the confrontational component as a counter strategy on the part of local, local communities in the course of intergroup interaction. The paper also provides statistical information on migration growth in the Russian Federation, interprets data from all-Russian research projects collected by a survey method, and a sociological survey of residents of the Yaroslavl region, characterizing the situation of migrants, their involvement in the functioning of economic sectors in the views of Russian residents (at the regional level), as well as revealing the content of relations between local communities with visiting representatives of a foreign cultural environment. An empirical study made it possible to draw a conclusion about the ambivalent response of the residents of the receiving country to the volumes of migration flows and the strategies of migrants. The author substantiated that multiple scaling of the probability of the conflict component in the socio-cultural interaction of the receiving party and arriving representatives of a foreign cultural environment requires a comprehensive implementation of programs for mutual adaptation of the above-named entities, agreed by government agencies and non-profit organizations as parity partners.

Probing chiral symmetry restoration with dileptons

Finite baryon density induces a mixing between the vector and axial-vector states, and yields multiple bumps and peaks around the vacuum masses of the ρ, ω and ϕ resonances in the spectral function. The modification become significantly pronounced when the mass difference between the parity partners decreases in dense matter. We propose that the emergent enhancement in the dilepton production rates serves as an excellent signature of the partially-restored chiral symmetry to be verified in heavy-ion collisions.

Sero-prevalence and determinants of Hepatitis B among a cohort of HIV-infected women of reproductive age in Nigeria.

IntroductionSub-Saharan Africa houses over two-thirds of the 37 million people living with human immunodeficiency virus (HIV) globally and of this, 5–20% are co-infected with Hepatitis B virus (HBV). This is double jeopardy, especially for women of reproductive age in these settings, who can transmit both viruses vertically as well as horizontally to their children. The objectives of this study were to investigate the prevalence and determinants of HBV among women of reproductive age living with HIV.MethodsThis was a cross-sectional study of HIV-infected women of reproductive age in Benue State, Nigeria. Participants were eligible for the study if they were HIV-infected women (ages 18–45 years) receiving care from any of the selected study sites. A global rapid hepatitis B surface antigen (HBsAg) antibody test strip was used to test for HBsAg in plasma. A pretested questionnaire was used to collect data on sociodemographic, clinical and lifestyle characteristics of participants. We estimated prevalence of HBV infection and used multivariable logistic regression to determine factors associated with the infection at a significance level of <0.05.ResultsA total of 6577 women were screened for HBsAg. The prevalence of HBV was 10.3% (95% CI: 9.5–10.9%). Age, parity and male partner’s HIV status were found to be associated with having HBV infection. Compared to women older than 40 years, the odds of HBV infection increased significantly with increasing age until age 35 years and decreased significantly with increasing parity (versus no parity). Women with HIV-infected partners and those without a partner had higher odds of HBV infection compared to women with HIV-negative partners.ConclusionHBV is hyperendemic among HIV-infected women of reproductive age in North Central Nigeria. Specific programs targeting HBV testing, vaccination and treatment of all women of reproductive age need to be developed in this resource-limited, high-need setting.

Signatures of chiral symmetry restoration in dilepton production

We study the structural change of the vector spectral function and integrated production rates of dileptons in the presence of the chiral mixing induced exclusively at finite density. The mixing produces multiple bumps and peaks around the vacuum masses of the ρ,ω and ϕ resonances in the spectral function. The arising modification becomes pronounced when the mass difference between parity partners decreases. In particular, the emergent enhancement around the vacuum ϕ meson in the production rates serves as an excellent signature of the partially-restored chiral symmetry in heavy-ion collisions.

Spectrum of Light- and Heavy-Baryons

A symmetry-preserving truncation of the strong-interaction bound-state equations is used to calculate the spectrum of ground-state $J=1/2^+$, $3/2^+$ $(qq^\prime q^{\prime\prime})$-baryons, where $q, q^\prime, q^{\prime\prime} \in \{u,d,s,c,b\}$, their first positive-parity excitations and parity partners. Using two parameters, a description of the known spectrum of 39 such states is obtained, with a mean-absolute-relative-difference between calculation and experiment of 3.6(2.7)%. From this foundation, the framework is subsequently used to predict the masses of 90 states not yet seen empirically.

Pati-Salam explanations of the B-meson anomalies

We provide a combined explanation of the increasingly tantalizing B-meson anomalies, both in {R}_{K^{left(ast right)}} and {R}_{D^{left(ast right)}} , in the Pati-Salam model with minimal matter content. This well-known model, based on the gauge group SU(4)LC × SU(2)L × SU(2)R, naturally contains a variety of scalar leptoquarks with related and restricted couplings. In particular we show that the seesaw-motivated scalar leptoquark within the representation ( overline{mathbf{10}} ,3,1) and its right-handed parity partner ( overline{mathbf{10}} ,1,3) can solve both anomalies while making testable predictions for related observables such as B → Kνν and B → Kμτ. The solution of the {R}_{K^{left(ast right)}} anomaly alone can be related to a type-II seesaw neutrino mass structure. Explaining also {R}_{D^{left(ast right)}} requires the existence of a light right-handed neutrino, which constrains the UV structure of the model.

Catalysis of partial chiral symmetry restoration by Δ matter

We study the phase structure of dense hadronic matter including $\Delta(1232)$ as well as N(939) based on the parity partner structure, where the baryons have their chiral partners with a certain amount of chiral invariant masses. We show that, in symmetric matter, $\Delta$ enters into matter in the density region of about one to four times of normal nuclear matter density, $\rho_B \sim 1 - 4\rho_0$. The onset density of $\Delta$ matter depends on the chiral invariant mass of $\Delta$, $m_{\Delta0}$: The lager $m_{\Delta0}$, the bigger the onset density. The $\Delta$ matter of $\rho_B \sim 1 - 4\rho_0$ is unstable due to the existence of $\Delta$, and the stable $\Delta$-nucleon matter is realized at about $\rho_B \sim 4\rho_0$, i.e., the phase transition from nuclear matter to $\Delta$-nucleon matter is of first order for small $m_{\Delta0}$, and it is of second order for large $m_{\Delta0}$. We find that, associated with the phase transition, the chiral condensate changes very rapidly, i.e., the chiral symmetry restoration is accelerated by \Delta matter. As a result of the accelerations, there appear $N^*$(1535) and $\Delta$(1700), which are the chiral partners to N(939) and ${\Delta}$(1232), in high density matter, signaling the partial chiral symmetry restoration. Furthermore, we find that complete chiral symmetry restoration itself is delayed by $\Delta$ matter. We also calculate the effective masses, pressure and symmetry energy to study how the transition to $\Delta$ matter affects such physical quantities. We observe that the physical quantities change drastically at the transition density.

New levels and reinvestigation of octupole correlations in 146,147La

High spin states of neutron-rich 146,147La have been reinvestigated by $\gamma$ - $\gamma$ - $ \gamma$ and $\gamma$ - $\gamma$ - $\gamma$ - $\gamma$ coincidence data from a 252Cf spontaneous fission experiment by using Gammasphere. Thirty-two new transitions in 146La are observed. Two new bands in 146La have been established. One of them is proposed to be the octupole parity partner of the previously known band. Twenty new transitions in 147La are observed. The ground state band of 147La has been established with a proposed $ 5/2^+$ band-head. Angular correlation of cascades has been used to study the spins and parities of the states. The B(E1)/B(E2) ratios and dipole moments of bands in 146, 147La have been measured.

Parity partners in the baryon resonance spectrum

We describe a calculation of the spectrum of flavour-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector-vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavour-antitriplet scalar, pseudoscalar and vector, and flavour-sextet axial-vector quark-quark correlations can all play an active role. The model yields reasonable masses for all systems studied, and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of their internal structure: ground-state, even parity baryons are constituted, almost exclusively, from like-parity diquark correlations; but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.