A bstract We present a method to determine the leadingorder (LO) contact term contributing to the nn → ppe − e − amplitude through the exchange of light Majorana neutrinos. Our approach is based on the representation of the amplitude as the momentum integral of a known kernel (proportional to the neutrino propagator) times the generalized forward Compton scattering amplitude n ( p 1 ) n ( p 2 ) W + ( k ) → $$ p\left({p}_1^{\prime}\right)p\left({p}_2^{\prime}\right){W}^{}(k) $$ p p 1 ′ p p 2 ′ W − k , in analogy to the Cottingham formula for the electromagnetic contribution to hadron masses. We construct modelindependent representations of the integrand in the low and highmomentum regions, through chiral EFT and the operator product expansion, respectively. We then construct a model for the full amplitude by interpolating between these two regions, using appropriate nucleon factors for the weak currents and information on nucleonnucleon ( NN ) scattering in the 1 S 0 channel away from threshold. By matching the amplitude obtained in this way to the LO chiral EFT amplitude we obtain the relevant LO contact term and discuss various sources of uncertainty. We validate the approach by computing themore »
Relativistic nucleon–nucleon potentials in a spindependent threedimensional approach
Abstract The matrix elements of relativistic nucleon–nucleon ( NN ) potentials are calculated directly from the nonrelativistic potentials as a function of relative NN momentum vectors, without a partial wave decomposition. To this aim, the quadratic operator relation between the relativistic and nonrelativistic NN potentials is formulated in momentumhelicity basis states. It leads to a single integral equation for the twonucleon (2 N ) spinsinglet state, and four coupled integral equations for twonucleon spintriplet states, which are solved by an iterative method. Our numerical analysis indicates that the relativistic NN potential obtained using CDBonn potential reproduces the deuteron binding energy and neutronproton elastic scattering differential and total crosssections with high accuracy.
 Award ID(s):
 2000029
 Publication Date:
 NSFPAR ID:
 10296609
 Journal Name:
 Scientific Reports
 Volume:
 11
 Issue:
 1
 ISSN:
 20452322
 Sponsoring Org:
 National Science Foundation
More Like this


Abstract The electronic structure of magnetic lanthanide atoms is fascinating from a fundamental perspective. They have electrons in a submerged open 4f shell lying beneath a filled 6s shell with strong relativistic correlations leading to a large magnetic moment and large electronic orbital angular momentum. This large angular momentum leads to strong anisotropies, i. e. orientation dependencies, in their mutual interactions. The longranged molecular anisotropies are crucial for proposals to use ultracold lanthanide atoms in spinbased quantum computers, the realization of exotic states in correlated matter, and the simulation of orbitronics found in magnetic technologies. Shortranged interactions and bond formation among these atomic species have thus far not been well characterized. Efficient relativistic computations are required. Here, for the first time we theoretically determine the electronic and rovibrational states of heavy homonuclear lanthanide Er 2 and Tm 2 molecules by applying stateoftheart relativistic methods. In spite of the complexity of their internal structure, we were able to obtain reliable spin–orbit and correlationinduced splittings between the 91 Er 2 and 36 Tm 2 electronic potentials dissociating to two groundstate atoms. A tensor analysis allows us to expand the potentials between the atoms in terms of a sum of seven spin–spin tensor operatorsmore »

A bstract The inclusive production of the J/ ψ and ψ (2S) charmonium states is studied as a function of centrality in pPb collisions at a centreofmass energy per nucleon pair $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 8 . 16 TeV at the LHC. The measurement is performed in the dimuon decay channel with the ALICE apparatus in the centreofmass rapidity intervals − 4 . 46 < y cms < − 2 . 96 (Pbgoing direction) and 2 . 03 < y cms < 3 . 53 (pgoing direction), down to zero transverse momentum ( p T ). The J/ ψ and ψ (2S) production cross sections are evaluated as a function of the collision centrality, estimated through the energy deposited in the zero degree calorimeter located in the Pbgoing direction. The p T differential J/ ψ production cross section is measured at backward and forward rapidity for several centrality classes, together with the corresponding average 〈 p T 〉 and $$ \left\langle {p}_{\mathrm{T}}^2\right\rangle $$ p T 2 values. The nuclear effects affecting the production of both charmonium states are studied using the nuclear modification factor. In the pgoing direction, a suppression of the production of both charmonium states ismore »

Deepinelastic scattering of electrons on a nucleon is a primary source of information about parton distribution functions (PDF) and transverse momentum distributions (TMD). The calculation of the QED corrections to SIDIS with any predetermined accuracy is crucial for studies of the 3D structure of the nucleon at JLab and future Electron Ion Collider (EIC). A majority of approved physics experiments that will be running with 12GeV electron beams at JLab to study the nucleon structure require percent level accuracies in the measurements of differential cross sections and polarization asymmetries. Neglecting electromagnetic corrections may lead to significant misinterpretation of data. Analysis of Todd singe spin asymmetries (SSA) in SIDIS, p (e, e'h) X, is based on an assumption that purely electromagnetic Todd effects are negligible.

Abstract The formation of clusters at subsaturation densities, as a result of manybody correlations, constitutes an essential feature for a reliable modelization of the nuclear matter equation of state (EoS). Phenomenological models that make use of energy density functionals (EDFs) offer a convenient approach to account for the presence of these bound states of nucleons when introduced as additional degrees of freedom. However, in these models clusters dissolve, by construction, when the nuclear saturation density is approached from below, revealing inconsistencies with recent findings that evidence the existence of shortrange correlations (SRCs) even at larger densities. The idea of this work is to incorporate SRCs in established models for the EoS, in light of the importance of these features for the description of heavyion collisions, nuclear structure and in the astrophysical context. Our aim is to describe SRCs at suprasaturation densities by using effective quasiclusters immersed in dense matter as a surrogate for correlations, in a regime where cluster dissolution is usually predicted in phenomenological models. Within the EDF framework, we explore a novel approach to embed SRCs within a relativistic meanfield model with density dependent couplings through the introduction of suitable inmedium modifications of the cluster properties, in particularmore »