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The thermonuclear burning rates for the {sup 14}C({alpha},{gamma}){sup 18}O radiative capture reaction are calculated at temperatures (0.3{lt}{ital T}{lt}10 GK) of relevance to the early universe. These rates are particularly important for estimating the formation of heavy elements in an inhomogeneous big bang nucleosynthesis, proposed by Applegate, Hogan, and Scherrer (that would suggest the quark-gluon to hadron phase transition is first order). We investigate the effect of a possible new broad ({Gamma}{approx}0.45 MeV) 1{sup {minus}} state, at approximately 9.0 MeV in {sup 18}O as would be deduced from the Yale-Michigan State University measurement of the beta-delayed alpha-particle emission of {sup 18}N and suggested by the Notre Dame-Caltech measurement of the nonresonant {sup 14}C({alpha},{gamma}){sup 18}O cross section. The gamma widths of the proposed broad state is estimated using the Alhassid, Gai, and Bertsch sum rule, and an experimental study is proposed.

Emulators for low-energy nuclear physics can provide fast & accurate predictions of bound-state and scattering observables for applications that require repeated calculations with different parameters, such as Bayesian uncertainty quantification. In this paper, we extend a scattering emulator based on the Kohn variational principle (KVP) to momentum space (including coupled channels) with arbitrary boundary conditions, which enable the mitigation of spurious singularities known as Kohn anomalies. We test it on a modern chiral nucleon-nucleon (NN) interaction, including emulation of the coupled channels. We provide comparisons between a Lippmann-Schwinger equation emulator and our KVP momentum-space emulator for a representative set of neutron-proton (np) scattering observables, and also introduce a quasi-spline-based approach for the KVP-based emulator. Our findings show that while there are some trade-offs between accuracy and speed, all three emulators perform well. Self-contained Jupyter notebooks that generate the results and figures in this paper are publicly available., 18 pages, 15 figures, matches published version

In this paper we study mass relations of mirror nuclei in terms of Coulomb energies calculated by the microscopic relativistic continuum Hartree-Bogoliubov theory. An additional term corresponding to the Nolen-Schiffer anomaly is assumed to take the same form as the well-known empirical formula. The resultant root-mean-square deviations of these mass relations are typically less than 100 keV. Based on these relations, 61 unknown proton-rich nuclear masses are predicted for $18\ensuremath{\leqslant}A\ensuremath{\leqslant}87$ with positive two-proton separation energies and are tabulated in the Supplemental Material of this paper.

Background: Recently, the researches of cluster structure have attracted considerable attention. Many microscopic structure models have been applied to describe the cluster configurations.Purpose: To better analyze the cluster structure and associate with the experimental observations, comparative studies are carried out in this paper by combining the nuclear structure model with the electron scattering theory.Method: The density distributions for candidate nuclei of normal and cluster states are obtained from the deformed relativistic Hartree-Bogoliubov (RHB) model. Using some moderate approximations, the corresponding Coulomb form factors $|{F}_{C}{(q)|}^{2}$ and inclusive cross sections for different configurations are calculated by the distorted wave Born approximation (DWBA) and coherent density fluctuation model (CDFM), respectively.Results: Comparing the $|{F}_{C}{(q)|}^{2}$ and inclusive cross sections of different configurations, the effects of nuclear cluster structure can be revealed, due to the differences of nuclear charge radii ${R}_{C}$ in coordinate space and the discrepancies of Fermi momentum ${k}_{F}$ in momentum space.Conclusions: Results illustrate that the cluster structure can be reflected from the elastic and inclusive electron scattering. The studies conducted in this paper provide a new approach to analyze the cluster configurations, and are also helpful to guide future electron scattering experiments.

In the previous paper I \cite{bhagwat20} we have shown that self-consistent Extended Thomas-Fermi (ETF) potentials and densities associated with a given finite-range interaction can be parametrized by generalized Fermi distributions. As a next step, a comprehensive calculation of ground-state properties of a large number of spherical and deformed even-even nuclei is carried out in the present work using the Gogny D1S force within the ETF scheme. The parametrized ETF potentials and densities of paper I are used to calculate the smooth part of the energy and the shell corrections within the Wigner-Kirkwood semiclassical averaging scheme. It is shown that the shell corrections thus obtained, along with a simple liquid drop prescription, yield a good description of ground-state masses and potential energy surfaces for nuclei spanning the entire periodic table., Comment: 17 pages, 8 Figures and 2 Tables

In this paper, we present a systematic study of Xe-Xe collisions at 5.44-TeV center-of-mass energy. We employ the Monte Carlo (hydrodynamics plus jets) $\mathrm{HYDJET}++$ model to calculate the pseudorapidity distribution, transverse momentum $({p}_{T})$ spectra and the elliptic flow $({v}_{2})$ of charged hadrons with different parameters in two geometrical configurations: body-body and tip-tip type of Xe-Xe collisions. The kinematic ranges $0l{p}_{T}l50\phantom{\rule{0.28em}{0ex}}\mathrm{GeV}/c$ and $|\ensuremath{\eta}|l0.8$ are considered for our paper. Results are obtained for seven classes of centrality. For comparison, we have shown results from the AMPT model with the string-melting version. The results obtained for Xe-Xe collision systems for minimum bias at midrapidity match well with the experimental data of the ALICE/CMS Collaborations. We observe that the pseudorapidity density depends on the size and geometry of the colliding system. The centrality dependence of average transverse momentum ($\ensuremath{\langle}{p}_{T}\ensuremath{\rangle}$) and average elliptic flow ($\ensuremath{\langle}{v}_{2}\ensuremath{\rangle}$) is also observed. The charged hadron properties also show clear dependence on the geometrical configuration of the collisions. Our model results have been compared to results obtained in the AMPT model. The $\mathrm{HYDJET}++$ model justifies data more closely than the AMPT model, the latter mostly overpredicts the experimental data.

Background: This is the third of a series of papers on baryon-baryon (BB) interactions, where the baryons are the lowest lying baryon states with spin and parity ${J}^{P}={(1/2)}^{+}$. The paper presents the extended-soft-core (ESC) model ESC16 for BB channels with strangeness $S=\ensuremath{-}2$.Purpose: The aim is to describe the ingredients of the $S=\ensuremath{-}2$ ESC16 potentials, to apply these two-body interactions to BB scattering and via $G$-matrix calculations to hypernuclear systems, and to compare with the presently available experimental information.Methods:The potentials for $S=\ensuremath{-}2$ are based on the SU(3) extension of the ESC potentials for the strangeness $S=0$ and $S=\ensuremath{-}1$ sectors, which are fitted to experimental nucleon-nucleon ($NN$), hyperon-nucleon ($YN$), and hyperon-hyperon ($YY$) data. Flavor SU(3) symmetry is broken only `kinematically' by the masses of the baryons and the mesons. For the $S=\ensuremath{-}2$ channels almost no experimental scattering data exist, and the information from hypernuclei is also rather limited. Nevertheless, in the fit to the $S=0$ and $S=\ensuremath{-}1$ sectors information from the Nagara event and the scarce experimental results on the $\mathrm{\ensuremath{\Xi}}N$ cross sections have been used as (mild) constraints to determine the free parameters in the simultaneous fit of the deuteron and the $NN\ensuremath{\bigoplus}YN$ scattering data. Therefore, the potentials for the $S=\ensuremath{-}2$ sectors are almost completely determined by the fits to the $NN, YN$ data, and SU(3) symmetry.Results: Various properties of the $S=\ensuremath{-}2$ potentials are illustrated by giving results for scattering lengths, bound states, phase parameters, and total cross sections. The well-depth ${U}_{\mathrm{\ensuremath{\Xi}}}$ is calculated and $\mathrm{\ensuremath{\Xi}}N G$-matrix interactions are derived and applied to ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$-capture reactions. Here, a phenomenological $\mathrm{\ensuremath{\Xi}}N$ interaction is added to describe the experiments. Furthermore, the ESC16 model supplemented with phenomenological SU(3) symmetric gaussian interactions is analyzed, and attractive $\mathrm{\ensuremath{\Xi}}N$ interactions are obtained. Combined with three-body forces derived from the ESC meson-pair vertices and the Fujita-Miyazawa interaction, yields good baryon well depths.Conclusions: The ESC16 $S=\ensuremath{-}2$ potentials, with kinematically broken SU(3) symmetry, provide a basis for realistic calculations in nuclear and hypernuclear physics. For a successful description of the well depth's ${U}_{N},{U}_{\mathrm{\ensuremath{\Lambda}}},{U}_{\mathrm{\ensuremath{\Sigma}}}$, and ${U}_{\mathrm{\ensuremath{\Xi}}}$ and hypernuclear $S=\ensuremath{-}2$ reactions phenomenological additions are needed.

International audience; Since its inception, the so-called surrogate-reaction method (SRM) has motivated the development and improvement of theories in connection to direct reactions. This paper reassesses some of the developments carried out in previous decades to deal with the representation of direct reaction probability data. It is believed that the experimental probabilities assimilation in the neutron cross section evaluation process can be better estimated using tools resulting from the efforts made over the years. This paper provides a new perspective on this issue both in terms of fission and γ-ray emission probabilities. In addition to the “natural” assimilation path that considers analyzing probabilities jointly with cross sections to extract nuclei structural properties, this article puts forward a prescription to convert, with a good level of confidence, measured direct-reaction induced probabilities to pseudoexperimental neutron-induced cross sections. This approach is named after the SRM as extended SRM (ESRM).

In this paper we study mass relations of mirror nuclei, with our focus on local correlations of deviations between theoretical nuclear masses and experimental data. With inclusion of such local correlations, we are able to construct very accurate mass formulas of mirror nuclei. The root-mean-square deviation (RMSD) of our formulas is $\ensuremath{\sim}69$ keV for nuclei with $10\ensuremath{\le}Z\ensuremath{\le}38$ and $ZgN+1$ in the AME2016 database, and, furthermore, the RMSD value becomes only 51 keV if one excludes three experimental data for which experimental uncertainties are larger than 150 keV. More than 240 proton-rich nuclear masses with mass number $A$ below 80 are predicted within the theoretical accuracy of 300 keV and are tabulated in the Supplemental Material of this paper. As a simple application, our predicted results are adopted to predict candidates with two-proton radioactivity.

In this paper we revisit mass relations of mirror nuclei by considering the odd-even feature in Coulomb energy. A substantial improvement and competitive accuracy of mass relations is achieved, with root-mean-squared deviations (RMSD) of only 93 keV; for the first time one is able to construct simple mass formulas for mirror nuclei with the RMSD below 100 keV in light- and medium-mass regions (mass number $A=20$--90) by using only four parameters. As a by-product we tabulate our predictions of masses excesses unaccessible experimentally in the Supplemental Material of this paper.

In this paper we study patterns of nuclear charge radii from three perspectives. The first is based on the so-called $\ensuremath{\delta}{R}_{i\mathrm{n}\ensuremath{-}j\mathrm{p}}$ relations, the root-mean-square deviation of which was reported to be 0.0072 fm for nuclei with both neutron number $N$ and proton number $Z$ $\ensuremath{\ge}8$, and are pointed out here to have actually a much smaller value, which is $\ensuremath{\approx}0.003$ fm for most nuclei with $N\ensuremath{\ge}28$ and $Z\ensuremath{\ge}28$. The second and third perspectives are new relations proposed in this paper. One is called the $\ensuremath{\delta}{R}_{\mathrm{nn}}$ relation enlightened from the so-called ``nonpairing'' interaction $\ensuremath{\delta}{V}_{\mathrm{nn}}$ in studies of nuclear binding energies, and the other is a linear dependence of nuclear charge radii in terms of valence nucleon numbers. All these relations are very accurate in most regions, and sizable deviations from these relations could be used to shed light on structural evolutions such as phase transitions and shape coexistence. About 830 unknown nuclear charge radii are enclosed in our Supplemental Material in this paper, with theoretical uncertainty below 0.03 fm.

Proton number fluctuation is sensitive observable to search for the QCD critical point in heavy-ion collisions. In this paper, we studied rapidity acceptance dependence of the proton cumulants and correlation functions in most central Au+Au collisions at sNN=5GeV from a microscopic hadronic transport model [the jet AA microscopic transportation model (JAM)]. At midrapidity, we found the effects of resonance weak decays and hadronic rescattering on the proton cumulants and correlation functions are small, but those effects get larger when further increasing the rapidity acceptance. On the other hand, we found the baryon number conservation is a dominant background effect on the rapidity acceptance dependence of proton number fluctuations. It leads to a strong suppression of cumulants and cumulant ratios as well as the negative proton correlation functions. We also studied those two effects on the energy dependence of cumulant ratios of net-proton distributions in most central Au+Au collisions at sNN=5−200GeV from the JAM model. This paper can serve as a noncritical baseline for a future QCD critical point search in heavy-ion collisions at the high baryon density region.

In this paper we report two simple relations of masses between corresponding mirror nuclei, the first of which is based on the regularity of empirical neutron-proton interactions, and the second of which is based on the regularity of the one-nucleon separation energy. We demonstrate that, for $N\ensuremath{\ge}10$, the empirical neutron-proton interaction of given nucleus with neutron number $N\ensuremath{-}1$ and proton number $Z$ (we use the convention that $N=Z$ in this paper), or abbreviated by the $(N\ensuremath{-}1,Z)$ nucleus, equals the neutron-proton interaction of its corresponding mirror nucleus, i.e., the $(N,Z\ensuremath{-}1)$ nucleus; we also demonstrate that one-proton separation energy ${S}_{p}$ and one-neutron separation energy ${S}_{n}$ of the $(N\ensuremath{-}k,Z)$ nucleus ($k=1,2,3,4$) equals one-neutron separation energy ${S}_{n}$ and one-proton separation energy ${S}_{p}$, respectively, of the $(N,Z\ensuremath{-}k)$ nucleus, after a simple correction of Coulomb energy and proton-neutron mass difference are considered. Numerical experiments show that these correlations provide us with a remarkably accurate approach to predict masses and separation energies of some proton-rich nuclei with neutron numbers from 10--46. Our predicted masses of proton-rich nuclei are tabulated as a Supplemental Material of this paper.

We have proposed in a series of previous papers a method to determine the effective axial-vector current coupling and the strength of the isoscalar proton-neutron pairing interaction for calculating the nuclear matrix elements of the neutrinoless double-$\beta$ decay by the quasiparticle random-phase approximation. The combination of these two parameters have had an uncertainty in this approach, but now this uncertainty is removed. In this paper, we apply our method to the neutrinoless double-$\beta$ decays of $^{136}$Xe and $^{130}$Te and predict the nuclear matrix elements and reduced half-lives. Our calculation is tested first by a self-check method using the two-neutrino double-$\beta$ decay, and this test ensures the application of our method to $^{136}$Xe. It turns out, however, that our method is not successful in $^{130}$Te. Further test is made for our calculation of the $\beta$ decay of $^{138}$Xe, and a satisfactory result is obtained.

Strutinsky's method is reviewed through a new understanding. This method depends on two free parameters: The smoothing parameter and the order of the curvature correction. It turns out that this method is nothing but a compromise between two fundamental conditions which are the so-called asymptotic limit which comes from the so-called remainder which imposes a small as possible smoothing parameter and the smoothing condition which forces that parameter to be, at least, slightly larger than the intershell spacing. In this paper, to find the best value of the smoothing parameter, a new criterion is proposed instead of the plateau condition. This new criterion is much more clear and free from ambiguities of the usual plateau condition. It is also found that the second free parameter, i.e., the order of the curvature correction, plays an accessory role since, it is connected intimately to the smoothing parameter, when the smoothing is realized. This paper provides a new and definitive insight into Strutinsky's method and its relationship with semiclassical methods.

Bethe wrote a pivotal paper providing the formalism for the theory of nuclear level densities. At that time, there were no known deformed nuclei, so Bethe made the assumption that all nuclei are spherical. After deformed nuclei were discovered, theorists predicted that the level density for such nuclei should be substantially enhanced over the level density for neighboring spherical nuclei. Despite these results, two comprehensive level density compilations based on neutron resonances counting at low neutron energy failed to find significant enhancement in level density for deformed nuclei. A recent paper has concluded that the Bethe spin distribution for nuclear levels is not appropriate for deformed nuclei. When a more accurate spin distribution is used in resonance analysis, it is found that an enhancement of approximately the predicted magnitude is observed.

Global spin alignment of vector mesons is a sensitive probe of system vorticity and particle production mechanism in relativistic heavy ion collisions. The measurement of global spin alignment is gaining increasing interest and deserves careful considerations. In this paper, we lay out a few practical issues that need to be taken care of when measuring global spin alignment of vector mesons. They are, the correction for event plane resolution, reconciling measurements made with different event planes, the correction for the effect of finite acceptance in pseudorapidity, and the consideration for measuring the azimuthal angle dependence. Insights and methodologies offered in this paper will help experiments to measure the global spin alignment properly and accurately., Comment: 6 pages. 4 figures. Accepted version by PRC

We employ an effective field theory (EFT) that exploits the separation of scales in the $p$-wave halo nucleus $^{8}\mathrm{B}$ to describe the process $^{7}\mathrm{Be}(p,\ensuremath{\gamma})^{8}\mathrm{B}$ up to a center-of-mass energy of 500 keV. The key leading-order (LO) and next-to-leading-order (NLO) results appeared in our earlier papers. Here we first present full details of the EFT calculation. We develop the lagrangian and power counting in terms of velocity scaling, thereby making manifest that the Coulomb force between $^{7}\mathrm{Be}$ and proton plays a major role in both scattering and radiative capture at these energies: Coulomb interactions must be included to all orders in ${\ensuremath{\alpha}}_{\mathrm{em}}$. The EFT calculation of the capture reaction is then carried out using Feynman diagrams computed in time-ordered perturbation theory, so we recover existing quantum-mechanical technology such as the Lippmann-Schwinger equation and the two-potential formalism for the treatment of the Coulomb-nuclear interference. Meanwhile, the strong interactions and the E1 operator are dealt with via EFT expansions in powers of momenta, with a breakdown scale set by the size of the $^{7}\mathrm{Be}$ core, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\approx}70$ MeV/c. This is worked out up to NLO in the EFT expansion; at this order the relevant physics in the different channels that enter the radiative capture reaction is encoded in ten different EFT couplings. The result is a model-independent parametrization for the reaction amplitude in the energy regime of interest. In the second part of the paper we consider other approaches that have been used to describe $^{7}\mathrm{Be}{(p,\ensuremath{\gamma})}^{8}\mathrm{B}$ in this energy range. We discuss the relationship of EFT to each of these approaches in qualitative terms and then make the connection quantitative by determining what the ten NLO EFT coefficients are in five different calculations that we consider representative. The EFT parameters are of natural size in all five cases, which shows that each of these earlier calculations corresponds to a particular point in the EFT parameter space. This understanding of the relationship between EFT and other ways of computing $^{7}\mathrm{Be}{(p,\ensuremath{\gamma})}^{8}\mathrm{B}$ allows us to update earlier results for the dependence of $S(0)$ on asymptotic normalization coefficients and scattering lengths, since EFT separates dependence on these asymptotic quantities from dependence on shorter-distance contributions to the matrix element. We also summarize the fit to experimental capture data presented in our earlier work and explain why we obtain an extrapolated $S(0)$ with a markedly smaller error bar than that of the previous standard evaluation. Finally, we demonstrate that the only ${\mathrm{N}}^{2}\mathrm{LO}$ corrections in $^{7}\mathrm{Be}(p,\ensuremath{\gamma})^{8}\mathrm{B}$ come from an inelasticity that is practically of $\mathrm{N}^{3}\mathrm{LO}$ size in the energy range of interest, and so the truncation error in our calculation is effectively $\mathrm{N}^{3}\mathrm{LO}$.

We discuss several misleading statements made in the article by Eccles et al. [Phys. Rev. C 96, 054611 (2017)]. In particular, contrary to what is claimed in that paper, the analysis of the borders of Kramers formula applicability as a function of temperature using the mean first-passage time formula was performed earlier in the paper by Gontchar et al. [Phys. Rev. C 82, 064606 (2010)].

Subsequent to the release of our original paper, we discovered in the context of preparing our technical supplement [1] for journal publication that a typographical error had existed in the text file that the analysis program used to construct the beam polarization "database" for both the original analysis, published in Ref. [2], and our final analysis. The electron-beam polarization P e and the analyzing power A y cancel exactly in the ratio R , which is proportional to the ratio P t / P l of the transferred polarization components. On the other hand, the extraction of the relative e dependence of P l / P Born l relies on knowledge of the beam polarization. As such, data taking was interrupted roughly every two days during the GEp - 2 ? experiment to perform invasive measurements of the beam polarization using the Hall C Moller polarimeter [3]. The run range affected by the typographical error was entirely contained within the data collected at Q 2 = 2.5 GeV 2 with a beam energy of E e = 3.680 GeV during January 2008. The data from this configuration were combined with the data collected at E e = 3.548 GeV due to the nearly complete overlap of these two settings in terms of Q 2 and e acceptance. It is worth remarking that this typographical error went unnoticed for so long because it only affected a small fraction of the data (less than half of the combined data for ? e ? = 0.790 ) and the difference between the actually assigned beam polarization and the polarization that should have been assigned was comparable in magnitude to the point-to-point systematic uncertainty of the measurement itself. As such, its effect did not show up in various diagnostic plots and statistical tests, such as the time stability of the extracted P l / P Born l ratio. The data for both E e = 3.548 and E e = 3.680 GeV were reprocessed using the corrected beam polarizations to determine the effect of the typographical error on the combined physics results at ? e ? = 0.790 . Because the value of P e cancels in the ratio R , changes in the assumed beam polarization can only affect the results for R via statistical fluctuations due to changes in the relative weighting of different run ranges in the unbinned maximum-likelihood estimators for R . These effects are negligible on the scale of both the statistical and the systematic uncertainties of the data. More noticeable changes are expected in the ratio P l / P Born l since the extracted value of P l is inversely proportional to the assumed value of P e . Table I shows the effect of the corrected beam polarization database on the polarization transfer observables for the combined data for the ? e ? = 0.790 setting, the only measurement affected by the typographical error. The analyzing power did not need to be recalibrated since it was determined using the ? e ? = 0.153 data, which were not affected by the typographical error. As expected, the change in the ratio R is negligible. The value of P Born l , which is computed event by event from the global fit described in the Appendix of the original paper and does not depend on P e , is also unchanged. The magnitudes of P t , P l , and P l / P Born l are reduced by a common multiplicative factor, reflecting the fact that the beam polarization had been underestimated for the run range affected by the typographical error. The most important result of the corrected analysis is that the ratio P l / P Born l has decreased by 0.0024 from 1.0167 to 1.0143, a change comparable in magnitude to the statistical uncertainty but small compared to the total and point-to-point systematic uncertainties. The P l / P Born l result for the original publication [2] would be reduced by the same multiplicative factor as the final result. The physics conclusions of both publications are not materially changed by this correction. (Table Presented). (Figure Presented).

In this paper, we study pair correlations in low-lying $T=0$ states for two typical cases of odd-odd $N=Z$ nuclei. The first case is six nucleons in a single $j=9/2$ shell, for which we study the $S$-broken-pair approximation, the isoscalar spin-1 pair condensation, and the isoscalar spin-aligned pair condensation, with schematic interactions. In the second case, we study pair approximations and correlation energies for $^{22}\mathrm{Na}$, $^{34}\mathrm{Cl}$, $^{46}\mathrm{V}$, $^{62}\mathrm{Ga}$, and $^{94}\mathrm{Ag}$ in multi-$j$ shells with effective interactions. A few $T=0$ states are found to be well represented by isoscalar nucleon pairs. The isoscalar spin-aligned pairs play an important role for the yrast $T=0$ states with $I\ensuremath{\sim}2j$ and $I\ensuremath{\sim}{I}_{\mathrm{max}}$ in $^{22}\mathrm{Na}$, $^{46}\mathrm{V}$, and $^{94}\mathrm{Ag}$. The overlap between the isoscalar $\mathcal{J}=1$ pair wave function and the shell-model wave function is around 0.5 for the $I=1,3$ states of $^{34}\mathrm{Cl}$ and the $I=1$ state of $^{94}\mathrm{Ag}$. The $I=9$ state of $^{62}\mathrm{Ga}$ is very well described by the isoscalar $\mathcal{J}=3$ pair condensation. The broken-pair approximation (which is similar to the 2-quasiparticle excitation of the isovector pair condensation) is appropriate for quite few states, such as the $I=1\ensuremath{-}3$ states of $^{34}\mathrm{Cl}$ and the $I=5$ state of $^{62}\mathrm{Ga}$. The correlation energies are presented in this paper. It is noted that the picture based on nucleon-pair wave functions is not always in agreement with the picture based on correlation energies.

The $\ensuremath{\alpha}$-decay chains of the isotopes $^{265\ensuremath{-}279}\mathrm{Mt}$ are predicted by comparing the $\ensuremath{\alpha}$ half-lives calculated within the Coulomb and proximity potential model for deformed nuclei of Santhosh et al. [Nucl. Phys. A 850, 34 (2011)] with the spontaneous fission half-lives using the shell-effect-dependent formula of Santhosh and Nithya [Phys. Rev. C 94, 054621 (2016)]. $\ensuremath{\alpha}$ half-lives also are calculated using different theoretical formalisms for comparison. The predicted half-lives and decay modes match well with the experimental results. The use of four different mass tables for calculating the $\ensuremath{\alpha}$- decay energies indicates that the mass table of Wang et al. [Chin. Phys. C 41, 030003 (2017)], which is based on the AME2016 atomic mass evaluation, is in better agreement with experimental results. The paper predicts long $\ensuremath{\alpha}$ chains from $^{265,267\ensuremath{-}269,271\ensuremath{-}273}\mathrm{Mt}$ with half-lives within experimental limits. The isotopes $^{274\ensuremath{-}276,278}\mathrm{Mt}$ exhibit 2\ensuremath{\alpha} chains followed by spontaneous fission. The 2\ensuremath{\alpha} chain of $^{266}\mathrm{Mt}$ and the 4\ensuremath{\alpha} chain of $^{270}\mathrm{Mt}$ end with electron capture. The isotopes $^{277,279}\mathrm{Mt}$ decay via spontaneous fission. We hope that the paper will open up new areas in this field.

Background: The nuclear Coulomb form factor $|{F}_{C}{(q)|}^{2}$ is a useful tool to study nuclear structure. For spherical nuclei, $|{F}_{C}{(q)|}^{2}$ can be calculated by combining the spherical relativistic mean-field (RMF) model and the distorted wave Born approximation (DWBA) method.Purpose: In a previous paper, the axially deformed RMF model + DWBA method was successfully applied to study the Coulomb form factors of deformed even-even nuclei. In this paper, we further extend this method to study the Coulomb form factors of deformed odd-$A$ nuclei.Method: First, the charge distributions of odd-$A$ nuclei are calculated with the deformed RMF model and expanded into multipole components. Next, with the multipole moment charge distributions, the Coulomb multipoles $C0, C2$, and $C4$ are calculated. Finally, by summing over Coulomb multipoles required, the Coulomb form factors of odd-$A$ nuclei can be obtained.Results: For deformed odd-$A$ nuclei, the theoretical Coulomb form factors calculated from the deformed RMF charge densities are in better agreement with the experimental data. For nuclei with $J\ensuremath{\ge}1$, the diffraction minima of Coulomb form factors are much flatter, which is due to the contributions of quadrupole charge distributions.Conclusions: Results indicate that the axially deformed RMF model can give reasonable descriptions for multipole moment charge distributions of odd-$A$ nuclei. The method in this paper can provide a useful guide for future experiments of electron scattering off exotic odd-$A$ nuclei.

The decay modes and half-lives of 96 isotopes of the superheavy element roentgenium (Rg) within the range of $255\ensuremath{\le}A\ensuremath{\le}350$ come under investigation in the present paper. The isotopes which lie beyond the proton drip line are identified by calculating the one-proton and two-proton separation energies. The $\ensuremath{\alpha}$-decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). For a theoretical comparison the $\ensuremath{\alpha}$ half-lives are also evaluated using the Viola-Seaborg semiempirical relation, the universal curve of Poenaru et al., the analytical formula of Royer, and the universal decay law of Qi et al. Spontaneous fission half-lives are computed with the shell-effect-dependent formula of Santhosh and Nithya and the semiempirical formula of Xu et al. The decay modes are predicted by comparing the $\ensuremath{\alpha}$-decay half-lives within the CPPMDN with the corresponding spontaneous fission half-lives computed by the shell-effect-dependent formula of Santhosh and Nithya. In our paper it is seen that the isotopes $^{255\text{--}271,273}\mathrm{Rg}$ lie beyond the proton drip line and hence decay through proton emission. The isotopes $^{272,274\text{--}277}\mathrm{Rg}$ exhibit long $\ensuremath{\alpha}$ chains. Three $\ensuremath{\alpha}$ chains are predicted from the isotopes $^{278\text{--}282}\mathrm{Rg}$. The isotopes $^{283\text{--}345}\mathrm{Rg}$ decay through spontaneous fission. The isotopes $^{346\text{--}350}\mathrm{Rg}$ are found to be stable against $\ensuremath{\alpha}$ decay. The theoretical results are compared with the available experimental results and are seen to be matching well. We hope that our predictions will be useful in future experimental investigations.

A recent paper [A. K. Rhine Kumar and P. Arumugam, Phys. Rev. C 92, 044314 (2015)] presented calculations of the giant dipole resonance width and $\ensuremath{\gamma}$-ray absorption cross sections for $^{152}\mathrm{Gd}$ at various temperatures and angular momenta and compared these with the experimental data. In the comparison of the cross sections, the authors used the linearized representations of the experimental spectra which actually represent the absorption cross sections divided by the $\ensuremath{\gamma}$-ray energy. In this Comment we make the comparison with the appropriate absorption cross sections derived from the data. The comparison shows a reasonable agreement if the higher value of the dipole-dipole interaction parameter, mentioned in the paper, is used in the calculation.

We reply to the Comment by Chakrabarty and Datar, wherein they have provided a better representation of giant dipole resonance (GDR) cross sections in $^{152}\mathrm{Gd}$, along with a revised data analysis. They have demonstrated that the results presented in our original paper calculated with higher dipole-dipole interaction strength ($\ensuremath{\eta}$) are in better agreement with the data. Consequently, both the cross sections and width could be explained with the same $\ensuremath{\eta}$, unlike in Sec. III of our original paper. However, the conclusions drawn in our original paper remain intact.

Finding the best model to describe the \ensuremath{\alpha}-decay process is an old and ongoing challenge in nuclear physics. The present paper systematically studied \ensuremath{\alpha}-decay half-lives for the favored ground-state-to-ground-state transitions of 344 isotopes of nuclei with 52 $\ensuremath{\le} Z \ensuremath{\le}$ 107 using 28 versions of the proximity potential model in the framework of the Wentzel-Kramers-Brillouin approximation. The present paper introduces the best proximity versions with the fewest deviations with respect to experimental values. The models for Proximity 1977 (Prox. 77)-set 4, Prox. 77-set 5, and Dutt 2011 with the root-mean-square deviations (RMSDs) of 1 were found to predict \ensuremath{\alpha}-decay half-lives better than the other models. Comparison with fusion studies shows that Dutt 2011 is an appropriate model both for \ensuremath{\alpha}-decay studies and for the prediction of the barrier characteristic in heavy-ion fusion reactions. The calculation of \ensuremath{\alpha}-decay half-lives was repeated for even-even, even-odd, odd-even, and odd-odd nuclei. This detailed comparative study reveals that for these versions the half-lives of the even-even nuclei with RMSDs of 0.6 show less deviation than the even-odd, odd-even, and odd-odd nuclei.

This paper calculates the elastic form factors for nucleons based on generalized parton distributions using an extended new ansatz introduced in http://dx.doi.org/10.1103/PhysRevC.105.025202 (Phys. Rev. C 105, no.2, 025202 (2022)). Different parton distribution functions (PDFs) are considered, and modifications are made to the free parameters of the new ansatz. The obtained results are systematically compared among the combinations of different PDFs and ansatzes for high ranges of momentum transfer, with $-t < 35 GeV^{-2}$. The minimum suitable parameters are used to parametrize the model. After obtaining the form factors, we proceed to compute the electric radius and the transversely unpolarized densities for the nucleon. In addition, we derive the parton distribution functions (PDFs) that depend on the impact parameter. Finally, we analyze the results by comparing them with the findings from other research and experimental data., 10 pages

Upon increasing significantly the nuclear elongation, the β-decay energy grows. This paper investigates within a simple yet partly microscopic approach, the transition rate of the β− decay of the Cf252 nucleus on the way to scission from the exit point for a spontaneous fission process. A rather crude classical approximation is made for the corresponding damped collective motion assumed to be one dimensional. Given these assumptions, we only aim in this paper at providing the order of magnitudes of such a phenomenon. At each deformation the energy available for β− decay, is determined from such a dynamical treatment. Then, for a given elongation, transition rates for the allowed (Fermi) 0+⟶0+ β decay are calculated from pair correlated wave functions obtained within a macroscopic-microscopic approach and then integrated over the time corresponding to the whole descent from exit to scission. The results are presented as a function of the damping factor (inverse of the characteristic damping time) in use in our classical dynamical approach. For instance, in the case of a descent time from the exit to the scission points of about 10−20 s, one finds a total rate of β decay corresponding roughly to 20 events per year and per milligram of Cf252. The inclusion of pairing correlations does not affect much these results.

Deformed nuclei possess enhanced moments violating time reversal invariance (T) and parity (P). Collective magnetic quadrupole moments (MQM) appear in nuclei with a quadrupole deformation (which have ordinary T,P-conserving collective electric quadrupole moments). Nuclei with an octupole deformation have a collective electric octupole moment, electric dipole moment (EDM), Schiff moment, and MQM in the intrinsic frame which rotates with the nucleus. In a state with definite angular momentum in the laboratory frame, these moments are forbidden by T and P conservation, meaning their expectation values vanish due to nuclear rotation. However, nuclei with an octupole deformation have doublets of close opposite parity rotational states with the same spin, which are mixed by T,P-violating nuclear forces. This mixing polarizes the orientation of the nuclear axis along the nuclear spin, and all moments existing in the intrinsic frame appear in the laboratory frame (provided the nuclear spin I is sufficiently large to allow such a moment). Such a mechanism produces enhanced T,P-violating nuclear moments. This enhancement also takes place in nuclei with a soft octupole vibration mode. In this paper we present updated estimates for the enhanced Schiff moment in isotopes of Eu, Sm, Gd, Dy, Er, Fr, Rn, Ac, Ra, Th, Pa, U, Np, and Pu in terms of the CP-violating π-meson–nucleon interaction constants g¯0,g¯1, and g¯2, the quantum chromodynamics parameter θ¯ and the quark chromo-EDMs. The implications of the enhanced T,P-violating moments to the search for axion dark matter in solid state experiments are also discussed, with potential alternative candidate compounds in which we may expect enhanced effects suggested.

This paper presents an extension of the MK single-pion production model [Kabirnezhad, Phys. Rev. D 97, 013002 (2018); Phys. Rev. D 102, 053009 (2020)] to high hadron invariant mass (W) and high momentum transfer (Q2) to conform to the predictions of perturbative QCD due to the quark-hadron duality evidence. New form factors for several resonances and nonresonant background in the electron-nucleon cross sections are determined taking into account the experimental data and improved evaluation techniques. Fits to electron-proton scattering data are used to constrain free parameters and to assign the related uncertainties of the model. The results from this work can be used to determine the vector current in the corresponding neutrino-nucleon cross sections, which is an important input for event generators in long-baseline neutrino-oscillation measurements.

In this paper, the parametrization of the nuclear structure function which is directly constrained by the dynamics of QCD in its high-energy limit is considered. This simple parameterization of the nuclear structure function is obtained from the proton experimental data by relying on a Froissart-bounded parametrization of the proton structure function. This phenomenological model describes high-energy QCD in the presence of saturation effects. Numerical calculations and comparison with available data from NMC, EMC and E665 Collaborations demonstrate that the suggested method by N.Armesto, C.A.Salgado and U.A. Wiedemann (ASW model) provides reliable ratio of nuclear structure functions $F_{2}^{A}/AF^{p}_{2}$ at low $x$ for light and heavy nuclei. The magnitude of nuclear shadowing is predicted for various kinematic regions and can be applied as well in analysis of ultra-high energy processes by future experiments at electron-ion colliders., will be appear in Phys.Rev.C

In this paper we show that double differences of separation energies for four neighboring nuclei cancel out with remarkable accuracy. The well-known Garvey-Kelson relations (GKs) and their generalizations are reduced to special cases of our reconstituted relations. Some of the new relations given in this paper are found to be in competitive or even better agreement with experimental data than the GKs.

We study the zero channel radius limit of Wigner's R-matrix theory for two cases, and show that it corresponds to non-relativistic effective quantum field theory. We begin with the simple problem of single-channel n-p elastic scattering in the 1S0 channel. The dependence of the R matrix width and level energy on the channel radius, "a" for fixed scattering length a0 and effective range r0 is determined. It is shown that these quantities have a simple pole for a critical value of the channel radius. The 3H(d,n)4He reaction cross section, analyzed with a two-channel effective field theory in the previous paper, is then examined using a two-channel, single-level R-matrix parametrization. The resulting S matrix is shown to be identical in these two representations in the limit that R-matrix channel radii are taken to zero. This equivalence is established by giving the relationship between the low-energy constants of the effective field theory (couplings and mass) and the R-matrix parameters (reduced width amplitudes and level energy). An excellent three-parameter fit to the observed astrophysical factor S is found for "unphysical" values of the reduced widths., Comment: 8 pages, 4 figures, part 2 of 2 companion papers

Collective negative parity states are believed to be related to octupole degrees of freedom in the nucleus in the geometrical model @1#. In the algebraic model, their description is the interacting boson model ~IBM! including s, p, d, and f bosons @2‐7#. One advantage of the algebraic model is the availability of analytical expressions for many physical quantities. The SU~3! limit describes a rotational spectrum @3‐5#. Analytical expressions for the energy can be written explicitly in terms of the Casimir operators of the corresponding group chain. Besides the energy spectrum, electromagnetic transition properties are important in determining the structure of a nucleus. In the sd-IBM, electromagnetic transition rates are obtained analytically @6,8#. Numerical studies have shown that the low-lying positive parity states are well-described by Ns dbosons, and the low-lying negative parity states are well described by coupling one pf boson with N21 sd bosons. In this limit, the sd bosons and pf bosons interact only via the quadrupole interaction. This is the weak correlation case. In this study, we adopt this assumption. In the strong correlation, sd bosons and pf bosons interact strongly, and the pf bosons and sd bosons are mixed strongly. Lac and Morrison @9# have derived analytical expressions in the strong correlation case using the 1/ N expansion technique. It is the purpose of this paper to give analytical expressions of E1, E2, E3, M1, and M2 transition rates involving low-lying negative parity states in the SU(3) sd 3SU(3) pf limit. The paper is organized as follows. In Sec. II, we give a brief description of the method of the calculation. In Sec. III we give the results. In Sec. IV we apply the results to some deformed nuclei. In Sec. V we give a brief summary.

An isoscalar $pn$ pair is expected to emerge in nuclei that have similar proton and neutron numbers and it may be a candidate for a deuteron ``cluster.'' There is, however, no experimental evidence for it. The purpose of this paper is to construct a new reaction model for the ($p,pd$) reaction including the deuteron breakup in the elementary process and the deuteron reformation by the final-state interactions (FSIs). How these processes contribute to the observables of the reaction is investigated. The distorted wave impulse approximation is extended in twofold. The elementary processes of the ($p,pd$), i.e., the $p$-$d$ elastic scattering and $d(p,p)pn$ reaction, are described with an impulse picture employing a nucleon-nucleon effective interaction. The three-body scattering waves in the final state of the ($p,pd$) reaction are calculated with the continuum-discretized coupled-channels method. The triple differential cross section (TDX) of the ($p,pd$) reaction is calculated with the new model. The elementary processes are described reasonably well with the present model. As for the ($p,pd$) reaction, the deuteron reformation can either increase or decrease the TDX height depending on the interference between the elastic and breakup channel of deuteron, while the \textit{back-coupling} effect always decreases it. It is shown that the deuteron reformation significantly changes the TDX of the ($p,pd$) reaction through the interference. It is important to include this process to quantitatively discuss the ($p,pd$) cross sections in view of the deuteron formation in nuclei. For more quantitative discussion regarding the experimental data, further improvement will be necessary., Comment: 11 pages, 5 figures

Chiral magnetic effect (CME) is a macroscopic transport phenomenon induced by quantum anomaly in the presence of chiral imbalance and an external magnetic field. Relativistic heavy ion collisions provide the unique opportunity to look for CME in a non-Abelian plasma, where the chiral imbalance is created by topological transitions similar to those occurring in the Early Universe. The isobar run at Relativistic Heavy Ion Collider was proposed as a way to separate the possible CME signal driven by magnetic field from the background. The first blind analysis results from this important experiment have been recently released by the STAR Collaboration. Under the pre-defined assumption of identical background in RuRu and ZrZr, the results are inconsistent with the presence of CME, as well as with all existing theoretical models (whether including CME or not). However the observed difference of backgrounds must be taken into account before any physical conclusion is drawn. In this paper, we show that once the observed difference in hadron multiplicity and collective flow are quantitatively taken into account, the STAR results could be consistent with a finite CME signal contribution of about $(6.8\pm2.6)\%$., Comment: 10 pages, 6 figures; final version

Chiral anomaly implies the existence of non-dissipative transport phenomena, such as the chiral magnetic effect. At second order in the derivative expansion, novel quantum transport phenomena emerge. In this paper, we focus on the anomalous transport driven by a combination of shear, vorticity and magnetic field. We find that the corresponding transport phenomena -- shear-induced chiral magnetic and chiral vortical effects (siCME and siCVE) -- induce characteristic charge correlations among the hadrons produced in heavy ion collisions. We propose the charge asymmetry of triangular flow as a signature of the anomalous transport, and estimate the strength of the signal, as well as the background, using hydrodynamical model simulations. We find that the signal-to-background ratio for the proposed observable is favorable for experimental detection., Comment: 7(main) + 12(supplementary) pages, 4 figures, final version

Jets produced in high energy heavy ion collisions are quenched by the quark gluon plasma. Measurements of these jets are influenced by the methods used to suppress and subtract the large, fluctuating background and the assumptions inherent in these methods. We compare the measurements of the background in Pb+Pb collisions at sNN = 2.76 TeV by the ALICE Collaboration (Abelev et al., J. High Energy Phys. 03 (2012) 053) to calculations in tenngen (a data-driven random background generator) and pythia angantyr. A detailed understanding of the width of these fluctuations is important for reducing uncertainties due to unfolding and extending measurements to lower momenta and larger resolution parameters. The standard deviation of the energy in random cones in tenngen is approximately in agreement with the form predicted in the ALICE paper, with deviations of 1–6%. The standard deviation of energy in random cones in angantyr exceeds the same predictions by approximately 13%. Deviations in both models can be explained by the assumption that the single-particle d2N/dydpT is a gamma distribution in the derivation of the prediction, whereas the model uses a different distribution. This indicates that model comparisons are potentially sensitive to the treatment of the background. We demonstrate that unfolding methods used to remove background fluctuations from jets can affect the comparisons between models and data, even in the absence of detector effects. Our findings suggest the need to more carefully consider methods for comparing simulations and data.

In a previous analysis of electroproduction of hypernuclei the cross sections were calculated in distorted-wave impulse approximation where the momentum of the initial proton in the nucleus was set to zero (the frozen-proton approximation). In this paper we go beyond this approximation assuming a non zero effective proton momentum due to proton Fermi motion inside of the target nucleus discussing also other kinematical effects. To this end we have derived a more general form of the two-component elementary electroproduction amplitude (Chew-Goldberger-Low-Nambu like) which allows its use in a general reference frame moving with respect to the nucleus-rest frame. The effects of Fermi motion were found to depend on kinematics and elementary amplitudes. The largest effects were observed in the contributions from the longitudinal and interference parts of the cross sections. The extension of the calculations beyond the frozen-proton approximation improved the agreement of predicted theoretical cross sections with experimental data and once we assumed the optimum on-shell approximation, we were able to remove an inconsistency which was previously present in the calculations., 20 pages, 7 figures, 5 tables

In this paper, an off-shell extrapolation is proposed for the Regge-model $\mathit{NN}$ amplitudes presented in a paper by Ford and Van Orden [Phys. Rev. C 87, 014004 (2013)] and in an eprint by Ford (arXiv:1310.0871 [nucl-th]). A prescription for extrapolating these amplitudes for one nucleon off-shell in the initial state is given. Application of these amplitudes to calculations of deuteron electrodisintegration is presented and compared to the limited available precision data in the kinematical region covered by the Regge model.

In a previous paper a semimicroscopic core-particle coupling method that includes the conventional strong coupling core-particle model as a limiting case was applied to spectra and electromagnetic properties of several well-deformed odd nuclei. This work coupled a large single particle space to the ground-state bands of the neighboring even cores. In this paper, we generalize the theory to include excited bands of the cores, such as \ensuremath{\beta} and \ensuremath{\gamma} bands, and thereby show that the resulting theory can account for the location and structure of all bands up to about 1.5 MeV. \textcopyright{} 1996 The American Physical Society.

In this paper we discuss the role of chiral symmetry in the description of the nucleon-nucleon interaction. We make use of a generalized Nambu--Jona-Lasinio model which exhibits chiral symmetry at the quark level and demonstrate how the various components of the boson-exchange model of the nucleon-nucleon interaction arise in this model. In this paper we make use of our recent analysis of correlated two-pion exchange. We have found that when correlated two-pion exchange is represented by an effective low-mass sigma meson, that meson may be seen to be the chiral partner of the pion. (That result pertains if the meson momentum {ital q} is spacelike such that {ital t}={ital q}{sup 2}{lt}0.) We give particular attention to the vertex functions appearing in the boson-exchange model. For monopole forms of the vertex functions the cutoff parameter {Lambda}{sup OBE} varies from about 1.3 GeV to 2.0 GeV. In our model the nucleon form factors are characterized by a parameter {lambda}. We show how large cutoff parameters, such as {Lambda}{sup OBE}, can arise in our analysis {ital even} {ital if} {ital the} {ital meson}-{ital nucleon} {ital vertex} {ital is} {ital soft}, {ital with} {ital a} {ital characteristic} {ital cutoff} {ital of} {ital about} 800more » {ital MeV}. We present the values of {lambda} that puts the NJL analysis in good agreement with the boson-exchange model of the nucleon-nucleon force.« less

Band-crossing phenomena in the high-spin region of deformed nuclei are studied in this paper. The power of modern computers for large-matrix diagonalization (up to 17 527{times}17 527) is exploited in a multinucleon-plus-rotor model. The interesting test case of {sup 154}Gd is treated in this paper. Though a small basis set of 9--18 Nilsson orbitals is used, the strict angular momentum and particle number conservation guarantees superior orthogonal microscopic wave functions for nucleon transfer calculations. This method takes account of pairing correlations among the valence particles and shows the effects of quadrupole pairing and the usually neglected j{center_dot}j recoil terms.

In this paper, we first demonstrate the applicability of a phenomenological two-parameter formula, as introduced by Holmberg and Lipas from the Bohr Hamiltonian in a way that is different from Wu and Zeng. Second, for the first time, we show microscopically that Holmberg's two-parameter formula can be applied to diatomic molecules and that it can fit the experimental data of rotational spectra of HCl, HBr, and HF very well when the parameters are determined by two arbitrary experimental levels. Third, we derive a two-parameter formula describing \ensuremath{\gamma}-soft rotational spectra which is similar to the Holmberg formula, called Holmberg-like formula in this paper. The experimental yrast lines of nine nuclei in the light rare-earth region are fitted by this formula. For the nuclear \ensuremath{\gamma} stiffness, \ensuremath{\gamma} softness, and for molecular rotational spectra, all the two-parameter formulas are obtained by making use of a single potential function. It is demonstrated that the reason why one can give a unified description for those three systems is the common rotational features like the widely used harmonic oscillator approximation. More importantly, from the more microscopic nuclear fermion dynamical symmetry model (FDSM), we may derive the variable moment of inertia (VMI) model, and further obtain the Holmberg formula and Holmberg-like formula under a certain approximation, as from the nuclear geometric description within the Bohr-Mottelson model (BM). It is shown that the bridge between the descriptions of the FDSM and of the BM is the effect of stretched alignment (stretching effect). According to another interpretation of the FDSM for the nuclear stretching effect, we also give a simple formula to explain the \ensuremath{\gamma}-soft rotational spectra and compare the formula with the above one. Finally, we give a phenomenological generalization to the combination of the Holmberg and Holmberg-like formulas, which may describe a transition from \ensuremath{\gamma}-stiff rotations to \ensuremath{\gamma}-soft rotations.

Recent works concerning QCD sum rules in nuclear matter have provided a new method for the calculation of the nucleon self-energy in matter. The results of that program depend strongly on assumptions made concerning the density dependence of four-quark condensates. If a factorization scheme is used to express the four-quark condensate values in terms of the two-quark condensates, the (Lorentz) scalar self-energy of the nucleon is small. However, if the four-quark condensates have only a weak density dependence, the nucleon scalar self-energy is large and attractive, and is in accordance with Dirac phenomenology. In this paper our goal is to show how the Nambu--Jona-Lasinio model may be used to calculate the density dependence of four-quark condensates. As an elementary example we calculate some of the contributions to a four-quark condensate containing scalar-isoscalar [ital [bar q]q] pairs. These calculations suggest only a very small modification of the value of the scalar-isoscalar condensate in matter relative to the value obtained in the factorization scheme. However, when we continue our study of the correlator of operators with the quantum numbers of the nucleon, we encounter some new and important terms among the four-quark condensates. These have their origin in an exchange process betweenmore » diquarks in the nucleon and diquarks present in the nucleons of the nuclear medium (nuclear matter). These terms may be taken to represent the effects of diquark condensates'' they are present in nuclear matter. If we use the interpolating field advocated by Ioffe we obtain a correction that eliminates the problematic density dependence of the four-quark condensates described above, if nuclear matter contains a similar amount of scalar ([ital T]=0) diquarks and axial-vector ([ital T]=1) diquarks. We believe that our paper provides increased confidence in the use of QCD sum rules in the study of the properties of hadrons in matter.« less