Nuclear Theory·nucl-th

Monday·November 21, 2016

11 papers—5 primary·6 cross-listed

01
Two Photon Transition Form Factor of $c ˉ c$ Quarkonia
Jing Chen🇨🇳 · Minghui Ding🇨🇳 · Lei Chang🇨🇳 · Yu-xin Liu🇨🇳
The two photon transition of $c ˉ c$ quarkonia are studied within a covariant approach based on the consistent truncation scheme of the quantum chromodynamics Dyson-Schwinger equation for the quark propagator and the Bethe--Salpeter equation for the mesons. We find the decay widths of $η_{c} \to γ γ$ and $χ_{c 0, 2} \to γ γ$ in good agreement with experimental data. The obtained transition form factor of $η_{c} \to γ γ^{*}$ for a wide range of space-like photon momentum transfer squared is also in agreement with the experimental findings of the BABAR experiment. As a by-product, the decay widths of $η_{b}, χ_{b 0, 2} \to γ γ$ and the transition form factor of $η_{b}, χ_{c 0, b 0} \to γ γ^{*}$ are predicted, which await for experimental test.
nucl-thhep-phPRD(2017)·43 citations
02
Description of the $^{11}$ Li $(p, d)^{10}$ Li transfer reaction using structure overlaps from a full three-body model
J. Casal · M. Gómez-Ramos · A. M. Moro
Recent data on the differential angular distribution for the transfer reaction $^{11}$ Li(p,d) $^{10}$ Li at $E / A = 5.7$ MeV in inverse kinematics are analysed within the DWBA reaction framework, using the overlap functions calculated within a three-body model of $^{11}$ Li. The weight of the different $^{10}$ Li configurations in the system's ground state is obtained from the structure calculations unambiguously. The effect of the $^{9}$ Li spin in the calculated observables is also investigated. We find that, although all the considered models succeed in reproducing the shape of the data, the magnitude is very sensitive to the content of $p_{1/2}$ wave in the $^{11}$ Li ground-state wave function. Among the considered models, the best agreement with the data is obtained when the $^{11}$ Li ground state contains a $\sim$ 31\% of $p_{1/2}$ wave in the $n$ - $^{9}$ Li subsystem. Although this model takes into account explicitly the splitting of the $1^{+}$ and $2^{+}$ resonances due to the coupling of the $p_{1/2}$ wave to the $3/ 2^{-}$ spin of the core, a similar degree of agreement can be achieved with a model in which the $^{9}$ Li spin is ignored, provided that it contains a similar p-wave content.
nucl-thPLB(2017)·25 citations
03
Renormalization of the three-boson system with short-range interactions revisited
E. Epelbaum🇩🇪 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪 · De-Liang Yao🇩🇪
We consider renormalization of the three-body scattering problem in low-energy effective field theory of self-interacting scalar particles by applying time-ordered perturbation theory to the manifestly Lorentz-invariant formulation. The obtained leading-order equation is perturbatively renormalizable and non-perturbatively finite and does not require a three-body counter term in contrast to its non-relativistic approximation.
nucl-thEPJA(2017)·19 citations
04
In-Medium Pion Valence Distribution Amplitude
K. Tsushima (Cruzeiro do Sul U.)🇧🇷 · J. P. B. C de Melo (Cruzeiro do Sul U.)🇧🇷
After a brief review of the quark-based model for nuclear matter, and some pion properties in medium presented in our previous works, we report new results for the pion valence wave function as well as the valence distribution amplitude in medium, which are presented in our recent article. We find that both the in-medium pion valence distribution and the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.
nucl-thhep-exhep-phnucl-exFew Body Syst.(2017)·3 citations
05
Two-photon exchange correction to $2 S$ - $2 P$ splitting in muonic helium-3 ions
Carl E. Carlson🇺🇸 · Mikhail Gorchtein🇩🇪 · Marc Vanderhaeghen🇩🇪
We calculate the two-photon exchange correction to the Lamb shift in muonic helium-3 ions within the dispersion relations framework. Part of the effort entailed making analytic fits to the electron- $^{3}$ He quasielastic scattering data set, for purposes of doing the dispersion integrals. Our result is that the energy of the 2 $S$ state is shifted downwards by two-photon exchange effects by 15.14(49) meV, in good accord with the result obtained from a potential model and effective field theory calculation.
nucl-thhep-phnucl-exPRA(2017)·37 citations
06
Condensate of excitations in moving superfluids
E.E. Kolomeitsev · D.N. Voskresensky
A possibility of the condensation of excitations with a non-zero momentum in rectilinearly moving and rotating superfluid bosonic and fermionic (with Cooper pairing) media is considered in terms of a phenomenological order-parameter functional at zero and non-zero temperature. The results might be applicable to the description of bosonic systems like superfluid $^{4}$ He, ultracold atomic Bose gases, charged pion and kaon condensates in rotating neutron stars, and various superconducting fermionic systems with pairing, like proton and color-superconducting components in compact stars, metallic superconductors, and neutral fermionic systems with pairing, like the neutron component in compact stars and ultracold atomic Fermi gases. Order parameters of the "mother" condensate in the superfluid and the new condensate of excitations, corresponding energy gains, critical temperatures and critical velocities are found.
↳ cond-mat.quant-gasastro-ph.HEnucl-thPTEP(2017)·4 citations
07
Chiral magnetic plasmons in anomalous relativistic matter
E. V. Gorbar🇺🇦 · V. A. Miransky🇨🇦 · I. A. Shovkovy🇺🇸 · P. O. Sukhachov🇨🇦
The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long-wavelength limit, but also affect the qualitative dependence on the wave vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.
↳ cond-mat.mes-hallhep-phhep-thnucl-thPRB(2017)·36 citations
08
Spin-1 diquark contributing to the formation of tetraquarks in light mesons
Hungchong Kim🇰🇷 · Myung-Ki Cheoun🇰🇷 · K. S. Kim🇰🇷
We apply a mixing framework to the light meson systems and examine tetraquark possibility in the scalar channel. In the diquark-antidiquark model, a scalar diquark is a compact object when its color and flavor structures are in ( $3 ˉ_{c}$ , $3 ˉ_{f}$ ). Assuming that all the quarks are in an $S$ -wave, the spin-0 tetraquark formed out of this scalar diquark has only one spin configuration, $∣ J, J_{12}, J_{34} ⟩ = ∣000 ⟩$ , where $J$ is the spin of the tetraquark, $J_{12}$ the diquark spin, $J_{34}$ the antidiquark spin. In this construction of the scalar tetraquark, we notice that another compact diquark with spin-1 in ( $6_{c}$ , $3 ˉ_{f}$ ) can be used although it is less compact than the scalar diquark. The spin-0 tetraquark constructed from this vector diquark leads to the spin configuration $∣ J, J_{12}, J_{34} ⟩ = ∣011 ⟩$ . The two configurations, $∣000 ⟩$ and $∣011 ⟩$ , are found to mix strongly through the color-spin interaction. The physical states can be identified with certain mixtures of the two configurations which diagonalize the hyperfine masses of the color-spin interaction. Matching these states to two scalar resonances $a_{0} (980), a_{0} (1450)$ or to $K_{0}^{*} (800), K_{0}^{*} (1430)$ depending on the isospin channel, we find that their mass splittings are qualitatively consistent with the hyperfine mass splittings which can support their tetraquark structure. To test our mixing scheme further, we also construct the tetraquarks for $J = 1, J = 2$ with the spin configurations, $∣111 ⟩$ and $∣211 ⟩$ , and discuss possible candidates in the physical spectrum.
↳ hep-phnucl-thEPJC(2017)·17 citations
09
Excluded-volume effects for a hadron gas in Yang-Mills theory
Paolo Alba🇩🇪 · Wanda Maria Alberico🇮🇹 · Alessandro Nada🇮🇹 · Marco Panero🇮🇹 · Horst Stöcker🇩🇪
When the multiplicities of particles produced in heavy-ion collisions are fitted to the hadron-resonance-gas model, excluded-volume effects play a significant role. In this work, we study the impact of such effects on the equation of state of pure Yang-Mills theory at low temperatures, comparing the predictions of the statistical model with lattice results. In particular, we present a detailed analysis of the SU(2) and SU(3) Yang-Mills theories: we find that, for both of them, the best fits to the equilibrium thermodynamic quantities are obtained when one assumes that the volume of different glueball states is inversely proportional to their mass. The implications of these findings for QCD are discussed.
↳ hep-lathep-phnucl-thPRD(2017)·26 citations
10
QCD-inspired determination of NJL model parameters
Paul Springer🇩🇪 · Jens Braun🇩🇪 · Stefan Rechenberger🇩🇪 · Fabian Rennecke🇩🇪
The QCD phase diagram at finite temperature and density has attracted considerable interest over many decades now, not least because of its relevance for a better understanding of heavy-ion collision experiments. Models provide some insight into the QCD phase structure but usually rely on various parameters. Based on renormalization group arguments, we discuss how the parameters of QCD low-energy models can be determined from the fundamental theory of the strong interaction. We particularly focus on a determination of the temperature dependence of these parameters in this work and comment on the effect of a finite quark chemical potential. We present first results and argue that our findings can be used to improve the predictive power of future model calculations.
↳ hep-phnucl-thEPJ Web Conf.(2017)·24 citations
11
Chiral transport of neutrinos in supernovae
Naoki Yamamoto🇯🇵
The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.
↳ astro-ph.HEhep-phnucl-thEPJ Web Conf.(2017)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE