Nuclear Theory·nucl-th

Friday·June 8, 2018

6 papers—3 primary·3 cross-listed

01
[Submitted on 7 Jun 2018]
Correlations imposed by the unitary limit between few-nucleon systems, nuclear matter and neutron stars
A. Kievsky · M. Viviani · D. Logoteta · I. Bombaci · L. Girlanda
The large values of the singlet and triplet two-nucleon scattering lengths locate the nuclear system close to the unitary limit. This particular position strongly constrains the low-energy observables in the three-nucleon system as depending on one parameter, the triton binding energy, and introduces correlations in the low energy sector of light nuclei. Here we analyze the propagation of these correlations to infinite nuclear matter showing that its saturation properties, the equation of state of $β$ -stable nuclear matter and several properties of neutron stars, as their maximum mass, are well determined solely by a few number of low-energy quantities of the two- and three-nucleon systems. In this way we make a direct link between the universal behavior observed in the low-energy region of few-nucleon systems and fundamental properties of nuclear matter and neutron stars.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1806.02636 [pdf]
PRL(2018)·55 citations
02
[Submitted on 7 Jun 2018]
Dissecting reaction calculations using Halo EFT and ab initio input
P. Capel · D. R. Phillips · H.-W. Hammer
We present a description of the break-up of halo nuclei in peripheral nuclear reactions by coupling a model of the projectile motivated by Halo Effective Field Theory with a fully dynamical treatment of the reaction using the Dynamical Eikonal Approximation. Our description of the halo system reproduces its long-range properties, i.e., binding energy and asymptotic normalization coefficients of bound states and phase shifts of continuum states. As an application we consider the break-up of 11Be in collisions on Pb and C targets. Taking the input for our Halo-EFT-inspired description of 11Be from a recent ab initio calculation of that system yields a good description of the Coulomb-dominated breakup on Pb at energies up to about 2 MeV, with the result essentially independent of the short-distance part of the halo wave function. However, the nuclear dominated break-up on C is more sensitive to short-range physics. The role of spectroscopic factors and possible extensions of our approach to include additional short-range mechanisms are also discussed.
Comments:
Published within Phys. Rev. C. We have corrected a few typos, most importantly, the depth V_{s1/2}^{(2)} in Table I for the sole cutoff \sigma=2 fm has been corrected to its actual value +3MeV fm^{-2}
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1806.02712 [pdf]
PRC(2018)·41 citations
03
[Submitted on 7 Jun 2018]
Combined few-body and mean-field model for nuclei
D. Hove🇩🇰 · E. Garrido🇪🇸 · P. Sarriguren🇪🇸 · D.V. Fedorov🇩🇰 · H.O.U. Fynbo🇩🇰 · A.S. Jensen🇩🇰 · N.T. Zinner🇩🇰
The challenging nuclear many-body problem is discussed along with classifications and qualitative descriptions of existing methods and models. We present detailed derivations of a new method where cluster correlations co-exist with an underlying mean-field described core-structure. The variation of an antisymmetrized product of cluster and core wave functions and a given nuclear interaction, provide sets of self-consistent equations of motion. After the applications on dripline nuclei we discuss perspectives with improvements and applications. In the conclusion we summarize while emphasizing the merits of consistently treating both short- and large-distance properties, few- and many-body correlations, ordinary nuclear structure, and concepts of halos and Efimov states.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1806.02768 [pdf]
J.Phys.G(2018)·6 citations
04
[Submitted on 7 Jun 2018] (cross-list from hep-ph)
Threshold corrections of $χ_{c} (2 P)$ and $χ_{b} (3 P)$ states and $J / ψ ρ$ and $J / ψ ω$ transitions of the $X (3872)$ in a coupled-channel model
J. Ferretti🇨🇳 · E. Santopinto🇮🇹
We calculate the masses of $χ_{c} (2 P)$ and $χ_{b} (3 P)$ states with threshold corrections in a coupled-channel model. Here, the meson quarkonium core is augmented by higher Fock components due to pair-creation effects. According to our results, we interpret the resonances characterized by very small threshold corrections, like $χ_{b} (3 P)$ 's, as almost pure quarkonia, and those states characterized by non-negligible threshold corrections, like the $X (3872)$ , as quarkonium cores plus meson-meson components. We also study the $J / ψ ρ$ and $J / ψ ω$ hidden-flavor strong decays of the $X (3872)$ . The decays are calculated as the dissociation of one of these components ( $D^{0} D ˉ^{0 *}$ ) into a $c c ˉ$ state ( $J / ψ$ ) plus a light meson ( $ρ$ or $ω$ ) in a potential model. In particular, our result for the ratio between the $X (3872) \to J / ψ ω$ and $J / ψ ρ$ widths (0.6) is compatible with the present experimental data ( $0.8 \pm 0.3$ ) within the experimental error.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1806.02489 [pdf]
PLB(2019)·45 citations
05
[Submitted on 7 Jun 2018] (cross-list from hep-ph)
Thermodynamic versus kinetic approach to polarization-vorticity coupling
Wojciech Florkowski🇵🇱 · Avdhesh Kumar🇵🇱 · Radoslaw Ryblewski🇵🇱
We critically compare thermodynamic and kinetic approaches, that have been recently used to study relations between the spin polarization and fluid vorticity in systems consisting of spin-one-half particles. The thermodynamic approach refers to general properties of global thermal equilibrium with a rigid-like rotation and demonstrates that the spin-polarization and thermal-vorticity tensors are equal. On the other hand, the kinetic approach uses the concept of the Wigner function and its semi-classical expansion. In most of the works done so far, the Wigner functions satisfy kinetic equations with a vanishing collision term. We show that this assumption restricts significantly applicability of such frameworks and, in contrast to many claims found in the literature, does not allow for drawing any conclusions regarding the relation between the thermal-vorticity and spin-polarization tensors, except for the fact that the two should be constant in global equilibrium. We further show how the kinetic-theory equations including spin degrees of freedom can be used to formulate a hydrodynamic framework for particles with spin. We define hydrodynamic equations starting separately from the formulation by de~Groot, van~Leeuwen, and van~Weert and from the canonical formalism. In the former case the energy-momentum tensor is symmetric and the spin tensor is conserved, while in the later case the energy-momentum tensor is not symmetric and the spin tensor is not conserved. Nevertheless, in the two cases the total angular momentum is always conserved. Interestingly, the two approaches are connected by the pseudo-gauge transformation, which we explicitly define.
Comments:
A significantly extended Sec. 8 where we define hydrodynamic equations starting separately from the formulation by de Groot et al. and the canonical formalism. Interestingly, the two approaches are connected by the pseudo-gauge transformation, which we explicitly define
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1806.02616 [pdf]
PRC(2018)·138 citations
06
[Submitted on 7 Jun 2018] (cross-list from hep-ph)
A neutrinoless double beta decay master formula from effective field theory
V. Cirigliano🇺🇸 · W. Dekens🇺🇸 · J. de Vries🇳🇱 · M. L. Graesser🇺🇸 · E. Mereghetti🇺🇸
We present a master formula describing the neutrinoless-double-beta decay ( $0 ν β β$ ) rate induced by lepton-number-violating (LNV) operators up to dimension nine in the Standard Model Effective Field Theory. We provide an end-to-end framework connecting the possibly very high LNV scale to the nuclear scale, through a chain of effective field theories. Starting at the electroweak scale, we integrate out the heavy Standard Model degrees of freedom and we match to an $S U (3)_{c} \otimes U (1)_{em}$ effective theory. After evolving the resulting effective Lagrangian to the QCD scale, we use chiral perturbation theory to derive the lepton-number-violating chiral Lagrangian. The chiral Lagrangian is used to derive the two-nucleon $0 ν β β$ transition operators to leading order in the chiral power counting. Based on renormalization arguments we show that in various cases short-range two-nucleon operators need to be enhanced to leading order. We show that all required nuclear matrix elements can be taken from existing calculations. Our final result is a master formula that describes the $0 ν β β$ rate in terms of phase-space factors, nuclear matrix elements, hadronic low-energy constants, QCD evolution factors, and high-energy LNV Wilson coefficients, including all the interference terms. Our master formula can be easily matched to any model where LNV originates at energy scales above the electroweak scale. As an explicit example, we match our formula to the minimal left-right-symmetric model in which contributions of operators of different dimension compete, and we discuss the resulting phenomenology.
Comments:
Published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1806.02780 [pdf]
JHEP(2018)·187 citations

Affiliations

first authorsco-authorsvia INSPIRE

Correlations imposed by the unitary limit between few-nucleon systems, nuclear matter and neutron stars

Dissecting reaction calculations using Halo EFT and ab initio input

Combined few-body and mean-field model for nuclei

Threshold corrections of χc​(2P) and χb​(3P) states and J/ψρ and J/ψω transitions of the X(3872) in a coupled-channel model

Thermodynamic versus kinetic approach to polarization-vorticity coupling

A neutrinoless double beta decay master formula from effective field theory

Affiliations

Threshold corrections of $χ_{c} (2 P)$ and $χ_{b} (3 P)$ states and $J / ψ ρ$ and $J / ψ ω$ transitions of the $X (3872)$ in a coupled-channel model