Nuclear Theory·nucl-th

Thursday·February 4, 2021

6 papers—2 primary·4 cross-listed

01
Parton collisional effect on the conversion of geometry eccentricities into momentum anisotropies in relativistic heavy-ion collisions
Long Ma🇨🇳 · Guo-Liang Ma🇨🇳 · Yu-Gang Ma🇨🇳
We explore parton collisional effects on the conversion of geometry eccentricities into azimuthal anisotropies in Pb+Pb collisions at $s_{N N}$ = 5.02 TeV using a multi-phase transport model. The initial eccentricity $ε_{n}$ (n = 2,3) and flow harmonics $v_{n}$ (n = 2,3) are investigated as a function of the number of parton collisions ( $N_{co l l}$ ) during the source evolution of partonic phase. It is found that partonic collisions leads to generate elliptic flow $v_{2}$ and triangular flow $v_{3}$ in Pb+Pb collisions. On the other hand, partonic collisions also result in an evolution of the eccentricity of geometry. The collisional effect on the flow conversion efficiency is therefore studied. We find that the partons with larger $N_{co l l}$ show a lower flow conversion efficiency, which reflect differential behaviors with respect to $N_{co l l}$ . It provides an additional insight into the dynamics of the space-momentum transformation during the QGP evolution from a transport model point of view.
nucl-thhep-phnucl-exPRC(2021)·8 citations
02
Large- $N_{c}$ analysis of two-nucleon neutrinoless double beta decay and charge-independence-breaking contact terms
Thomas R. Richardson🇺🇸 · Matthias R. Schindler🇺🇸 · Saori Pastore🇺🇸 · Roxanne P. Springer🇺🇸
The interpretation of experiments that search for neutrinoless double beta decay relies on input from nuclear theory. Cirigliano et al. recently showed that, for the light Majorana exchange formalism, effective field theory calculations require a $nn \to pp e^{-} e^{-}$ contact term at leading order. They estimated the size of this contribution by relating it to measured charge-independence-breaking (CIB) nucleon-nucleon interactions and making an assumption about the relative sizes of CIB operators. We show that the assumptions underlying this approximation are justified in the limit of the number of colors $N_{c}$ being large. We also obtain a large- $N_{c}$ hierarchy among CIB nucleon-nucleon interactions that is in agreement with phenomenological results.
nucl-thhep-phPRC(2021)·36 citations
03
Open Quantum Systems for Quarkonia
Xiaojun Yao🇺🇸
I review recent applications of the open quantum system framework in the understanding of quarkonium suppression in heavy-ion collisions, which has been used as a probe of the quark-gluon plasma for decades. The derivation of the Lindblad equations for quarkonium in both the quantum Brownian motion and the quantum optical limits and their semiclassical counterparts is explained. The hierarchy of time scales assumed in the derivation is justified from the separation of energy scales in nonrelativistic effective field theories of QCD. Physical implications of the open quantum system approach are also discussed. Finally, I list some open questions for future studies.
↳ hep-phhep-exnucl-thInt.J.Mod.Phys.A(2021)·100 citations
04
Insights into the Emergence of Mass from Studies of Pion and Kaon Structure
Craig D. Roberts🇨🇳 · David G. Richards🇺🇸 · Tanja Horn🇺🇸 · Lei Chang🇨🇳
There are two mass generating mechanisms in the standard model of particle physics (SM). One is related to the Higgs boson and fairly well understood. The other is embedded in quantum chromodynamics (QCD), the SM's strong interaction piece; and although responsible for emergence of the roughly 1 GeV mass scale that characterises the proton and hence all observable matter, the source and impacts of this emergent hadronic mass (EHM) remain puzzling. As bound states seeded by a valence-quark and -antiquark, pseudoscalar mesons present a simpler problem in quantum field theory than that associated with the nucleon. Consequently, there is a large array of robust predictions for pion and kaon properties whose empirical validation will provide a clear window onto many effects of both mass generating mechanisms and the constructive interference between them. This has now become significant because new-era experimental facilities, in operation, construction, or planning, are capable of conducting such tests and thereby contributing greatly to resolving the puzzles of EHM. These aspects of experiment, phenomenology, and theory, along with contemporary successes and challenges, are sketched herein, simultaneously highlighting the potential gains that can accrue from a coherent effort aimed at finally reaching an understanding of the character and structure of Nature's Nambu-Goldstone modes.
↳ hep-phhep-exhep-latnucl-ex+1PPNP(2021)·214 citations
05
Role of dense matter in tidal deformations of inspiralling neutron stars and in gravitational waveform with unified equations of state
Loïc Perot🇧🇪 · Nicolas Chamel🇧🇪
The role of dense-matter properties in the tidal deformability of a cold nonaccreted neutron star is further investigated. Using the set of Brussels-Montreal unified equations of state, we have computed the gravitoelectric Love numbers $k_{ℓ}$ and the gravitomagnetic Love numbers $j_{ℓ}$ up to $ℓ = 5$ . Their relative importance and their sensitivity to the symmetry energy and the neutron-matter stiffness are numerically assessed. Their impact on the phase of the gravitational-wave signal emitted by binary neutron star inspirals is also discussed.
↳ gr-qcastro-ph.HEnucl-thPRC(2021)·12 citations
06
On the structure of the correlation coefficients S(E_e) and U(E_e) of the neutron beta decay
A. N. Ivanov🇦🇹 · R. Höllwieser🇦🇹 · N. I. Troitskaya🇦🇹 · M. Wellenzohn🇦🇹 · Ya. A. Berdnikov🇷🇺
In the standard effective V - A theory of low-energy weak interactions (i.e. in the Standard Model (SM)) we analyze the structure of the correlation coefficients S(E_e) and U(E_e), where E_e is the electron energy. These correlation coefficients were introduced to the electron-energy and angular distribution of the neutron beta decay by Ebel and Feldman ( Nucl. Phys. 4, 213 (1957)) in addition to the set of correlation coefficients proposed by Jackson et al. (Phys. Rev. 106, 517 (1957)). The correlation coefficients $S (E_{e})$ and $U (E_{e})$ are induced by simultaneous correlations of the neutron and electron spins and electron and antineutrino 3-momenta. These correlation structures do no violate discrete P, C and T symmetries. We analyze the contributions of the radiative corrections of order O(alpha/pi), taken to leading order in the large nucleon mass m_N expansion, and corrections of order O(E_e/m_N), caused by weak magnetism and proton recoil. In addition to the obtained SM corrections we calculate the contributions of interactions beyond the SM (BSM contributions) in terms of the phenomenological coupling constants of BSM interactions by Jackson et al. (Phys. Rev. 106, 517 (1957)) and the second class currents by Weinberg (Phys. Rev. 112, 1375 (1958)).
↳ hep-phhep-exnucl-exnucl-thPRC(2021)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Parton collisional effect on the conversion of geometry eccentricities into momentum anisotropies in relativistic heavy-ion collisions

Large-Nc​ analysis of two-nucleon neutrinoless double beta decay and charge-independence-breaking contact terms

Open Quantum Systems for Quarkonia

Insights into the Emergence of Mass from Studies of Pion and Kaon Structure

Role of dense matter in tidal deformations of inspiralling neutron stars and in gravitational waveform with unified equations of state

On the structure of the correlation coefficients S(E_e) and U(E_e) of the neutron beta decay

Affiliations

Large- $N_{c}$ analysis of two-nucleon neutrinoless double beta decay and charge-independence-breaking contact terms