New measurements of high-momentum nucleons and short-range structures in nuclei
N. Fomin, J. Arrington, R. Asaturyan, F. Benmokhtar, W. Boeglin, P. Bosted, A. Bruell, M. H. S. Bukhari, E. Chudakov, B. Clasie, S. H. Connell, M. M. Dalton, A.… 展开作者
N. Fomin, J. Arrington, R. Asaturyan, F. Benmokhtar, W. Boeglin, P. Bosted, A. Bruell, M. H. S. Bukhari, E. Chudakov, B. Clasie, S. H. Connell, M. M. Dalton, A. Daniel, D. B. Day, D. Dutta, R. Ent, L. El Fassi, H. Fenker, B. W. Filippone, K. Garrow, D. Gaskell, C. Hill, R. J. Holt, T. Horn, M. K. Jones, J. Jourdan, N. Kalantarians, C. E. Keppel, D. Kiselev, M. Kotulla, R. Lindgren, A. F. Lung, S. Malace, P. Markowitz, P. McKee, D. G. Meekins, H. Mkrtchyan, T. Navasardyan, G. Niculescu, A. K. Opper, C. Perdrisat, D. H. Potterveld, V. Punjabi, X. Qian, P. E. Reimer, J. Roche, V. M. Rodriguez, O. Rondon, E. Schulte, J. Seely, E. Segbefia, K. Slifer, G. R. Smith, P. Solvignon, V. Tadevosyan, S. Tajima, L. Tang, G. Testa, R. Trojer, V. Tvaskis, W. F. Vulcan, C. Wasko, F. R. Wesselmann, S. A. Wood, J. Wright, X. Zheng
We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data also include the kinematic region where three-nucleon correlations are expected to dominate.
High energy heavy-ion collisions produce large amounts of light nuclei and hype nuclei, especially at high baryon density around collision energy of several GeV. These light nuclei and hyper nuclei carry the information of nucleon-nucleon and hyperon-nucleon interactions and affect the chemical composition and properties of the collision system. This proceeding is a brief review for the recent measurements on light nuclei collective flow, including directed flow $v_1$, elliptic flow $v_2$, and high order flow coefficients, at finite and high baryon densities from different experiments. The lig…
While the main features of atomic nuclei are well described by nuclear mean-field models, there is a large and growing body of evidence which indicates an important additional role played by spatially-correlated nucleon-nucleon structures. The role of nucleonic structures was first suggested by Heidmann in 1950 to explain pick-up reactions of energetic nucleons. Since then a steady flux of new experimental evidence has confirmed the presence of similar structures inside atomic nuclei, dominated by correlations between pairs of nucleons. The role of these internal nucleon-nucleon correlations h…
We propose a phenomenological approach to examine the role of short- and long-range nucleon-nucleon correlations in the quenching of single-particle strength in atomic nuclei and their evolution in asymmetric nuclei and neutron matter. These correlations are thought to be the reason for the quenching of spectroscopic factors observed in $\rm (e,e'p)$, $\rm (p,2p)$ and transfer reactions. We show that the recently observed increase of the high-momentum component of the protons in neutron-rich nuclei is consistent with the reduced proton spectroscopic factors. Our approach connects recent result…
The number of nucleon (NN) scaling of the directed flow $v_1$ and elliptic flow ($v_{2}$) as well as the nuclear modification factor ($R_{cp}$) are tested for light nuclei which are produced in 0.4$A$ GeV $^{197}Au + ^{197}Au$ collisions at different impact parameters with two different in-medium nucleon-nucleon cross sections in the framework of an isospin-dependent quantum molecular dynamics (IQMD) model. In that energy domain, the emission of light nuclei can be well described by the squeeze-out phenonomenon. The results show a nice NN scaling behavior for flow parameters $v_{1}$, $v_{2}$ a…
In the past decades, it has been shown that the three-body force is necessary for a fully microscopic understanding of nuclear many-body systems, and thus efficient schemes for storing and utilizing three-body matrix elements have been developed. However, three-body matrix elements still demand a lot of memory and/or storage and it readily exceeds the limitation of the state-of-the-art supercomputers. We explore the possibility of mimicking the effects of three-body forces in medium-mass region, especially lower $pf$ shell, by density-dependent effective nucleon-nucleon interactions combining …
For more than half a century, nucleons are considered to move continuously in the nuclei. Recent electron-scattering experiments indicate about 20$\sim$25\% nucleons in heavier nuclei are involved in the neutron-proton short-range correlations. Nucleons in the nuclei thus have abnormal behavior unlike those in the non-interaction fermi gas. In the neutron-rich nuclei, around the Fermi momentum, the neutron-proton short-range correlations lead to a momentum gap in the proton momentum distribution, which is circumstantially supported by the pionic experimental data. Likewise, there should also b…
The Gamow-Teller strength in nuclei can be strongly affected by the internal degrees of freedom of the nucleon. It is demonstrated that this feature is unique to the Gamow-Teller. Excitation modes that involve spatial degrees of freedom are much less influenced by the internal excitation of nucleons. The fact that the observed Gamow-Teller strength is quenched by 30-40 percent in all nuclei suggests that indeed this is due to the nucleon excitation in nuclei.
We present a theoretical study of the Maris polarization effect and its application in quasi-free reactions to assess information on the structure of exotic nuclei. We discuss the uncertainties in the calculations of triple differential cross sections and of analyzing powers due the choices of various nucleon-nucleon interactions the optical potentials and limitations of the method. Our calculations explore a large number of choices for the nucleon-nucleon (NN) interactions and the optical potential for nucleon-nucleus scattering. Our study implies that polarization variables in (p,2p) reactio…
The short-range correlation (SRC) induced by the tensor force in the isosinglet neutron-proton interaction channel leads to a high-momentum tail (HMT) in the single-nucleon momentum distributions n(k) in nuclei. Owing to the remaining uncertainties about the tensor force, the shape of the nucleon HMT may be significantly different from the dilute interacting Fermi gas model prediction $n(k) \sim1/k^4$ similar to the HMT in cold atoms near the unitary limit. Within an isospin- and momentum-dependent Boltzmann-Uehling-Uhlenbeck transport model incorporating approximately the nucleon HMT, we inve…
Local chiral effective field theory interactions have recently been developed and used in the context of quantum Monte Carlo few- and many-body methods for nuclear physics. In this work, we go over detailed features of local chiral nucleon-nucleon interactions and examine their effect on properties of the deuteron, paying special attention to the perturbativeness of the expansion. We then turn to three-nucleon interactions, focusing on operator ambiguities and their interplay with regulator effects. We then discuss the nuclear Green's function Monte Carlo method, going over both wave-function …
With the development of radioactive beam facilities, studies concerning the shell evolution of unstable nuclei have recently gained prominence. Intruder components, particularly s-wave intrusion, in the low-lying states of light neutron-rich nuclei near N=8 are of importance in the study of shell evolution. The use of single-nucleon transfer reactions in inverse kinematics has been a sensitive tool that can be used to quantitatively investigate the single-particle orbital component of selectively populated states. The spin-parity, spectroscopic factor (or single-particle strength), and effecti…
Background: Multi-nucleon transfer reactions have recently attracted attention as a possible path to the synthesis of new neutron-rich heavy nuclei. Purpose: We study transfer reactions involving massive nuclei with the intention of understanding if the semi-classical model GRAZING coupled to an evaporation and fission competition model can satisfactory reproduce experimental data on transfer reactions in which fission plays a role. Methods: We have taken the computer code GRAZING and have added fission competition to it (GRAZING-F) using our current understanding of $Γ_n/Γ_f$, fission barrier…
