Nuclear Theory·nucl-th

Friday·July 3, 2020

15 papers—7 primary·8 cross-listed

08
Precision tests of fundamental physics with $η$ and $η^{'}$ mesons
Liping Gan🇺🇸 · Bastian Kubis🇩🇪 · Emilie Passemar🇺🇸 · Sean Tulin🇨🇦
Decays of the neutral and long-lived $η$ and $η^{'}$ mesons provide a unique, flavor-conserving laboratory to test low-energy Quantum Chromodynamics and search for new physics beyond the Standard Model. They have drawn world-wide attention in recent years and have inspired broad experimental programs in different high-intensity-frontier centers. New experimental data will offer critical inputs to precisely determine the light quark mass ratios, $η$ - $η^{'}$ mixing parameters, and hadronic contributions to the anomalous magnetic moment of the muon. At the same time, it will provide a sensitive probe to test potential new physics. This includes searches for hidden photons, light Higgs scalars, and axion-like particles that are complementary to worldwide efforts to detect new light particles below the GeV mass scale, as well as tests of discrete symmetry violation. In this review, we give an update on theoretical developments, discuss the experimental opportunities, and identify future research needed in this field.
↳ hep-phhep-exnucl-exnucl-thPhys.Rept.(2022)·179 citations
09
"QM19 summary talk": Outlook and future of heavy-ion collisions
Constantin Loizides (ORNL)🇺🇸
A summary of the QM19 conference is given by highlighting a few selected results. These are discussed as examples to illustrate the exciting future of heavy-ion collisions and the need for further instrumentation. (The arXiv version is significantly longer than the printed proceedings, with more figures.)
↳ nucl-exnucl-thNPA(2021)·6 citations
10
Next-to-leading order Balitsky-Kovchegov equation beyond large $N_{c}$
T. Lappi🇫🇮 · H. Mäntysaari🇫🇮 · A. Ramnath🇫🇮
We calculate finite- $N_{c}$ corrections to the next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation. We find analytical expressions for the necessary correlators of six Wilson lines in terms of the two-point function using the Gaussian approximation. In a suitable basis, the problem reduces from the diagonalization of a six-by-six matrix to the diagonalization of a three-by-three matrix, which can easily be done analytically. We study numerically the effects of these finite- $N_{c}$ corrections on the NLO BK equation. In general, we find that the finite- $N_{c}$ corrections are smaller than the expected $1/ N_{c}^{2} \sim 10%$ . The corrections may be large for individual correlators, but have less of an influence on the shape of the amplitude as a function of the dipole size. They have an even smaller effect on the evolution speed as a function of rapidity.
↳ hep-phnucl-thPRD(2020)·30 citations
11
Energy scan/dependence of kinetic freeze-out scenarios of multi-strange and other identified particles in central nucleus-nucleus collisions
Muhammad Waqas🇨🇳 · Fu-Hu Liu🇨🇳 · Rui-Qin Wang🇨🇳 · Irfan Siddique🇨🇳
The transverse momentum (mass) spectra of the multi-strange and non-multi-strange (i.e. other identified) particles in central gold-gold (Au-Au), lead-lead (Pb-Pb), argon-muriate (Ar-KCl) and nickel-nickel (Ni-Ni) collisions over a wide energy range have been studied in this work. The experimental data measured by various collaborations have been analyzed. The blast-wave fit with Tsallis statistics is used to extract the kinetic freeze-out temperature and transverse flow velocity from the experimental data of transverse momentum (mass) spectra. The extracted parameters increase with the increase of collision energy and appear with the trend of saturation at the Beam Energy Scan (BES) energies at the Relativistic Heavy Ion Collider (RHIC). This saturation implies that the onset energy of phase transition of partial deconfinement is 7.7 GeV and that of whole deconfinement is 39 GeV. Furthermore, the energy scan/dependence of kinetic freeze-out scenarios are observed for the multi-strange and other identified particles, though the multiple freeze-out scenarios are also observed for various particles.
↳ hep-phhep-exnucl-exnucl-thEPJA(2020)·41 citations
12
Dynamic scale anomalous transport in QCD with electromagnetic background
Mamiya Kawaguchi🇨🇳 · Shinya Matsuzaki🇨🇳 · Xu-Guang Huang🇨🇳
We discuss phenomenological implications of the anomalous transport induced by the scale anomaly in QCD coupled to an electromagnetic (EM) field, based on a dilaton effective theory. The scale anomalous current emerges in a way perfectly analogous to the conformal transport current induced in a curved spacetime background, or the Nernst current in Dirac and Weyl semimetals -- both current forms are equivalent by a "Weyl transformation". We focus on a spatially homogeneous system of QCD hadron phase, which is expected to be created after the QCD phase transition and thermalization. We find that the EM field can induce a dynamic oscillatory dilaton field which in turn induces the scale anomalous current. As the phenomenological applications, we evaluate the dilepton and diphoton productions induced from the dynamic scale anomalous current, and find that those productions include a characteristic peak structure related to the dynamic oscillatory dilaton, which could be tested in heavy ion collisions. We also briefly discuss the out-of-equilibrium particle production created by a nonadiabatic dilaton oscillation, which happens in a way of the so-called tachyonic preheating mechanism.
↳ hep-phhep-exhep-thnucl-thJHEP(2020)·10 citations
13
Nuclear spin-dependent parity-violating effects in light polyatomic molecules
Yongliang Hao🇳🇱 · Petr Navrátil🇨🇦 · Eric B. Norrgard🇺🇸 · Miroslav Iliaš🇸🇰 · Ephraim Eliav🇮🇱 · Rob G. E. Timmermans🇳🇱 · Victor V. Flambaum🇦🇺 · Anastasia Borschevsky🇳🇱
Measurements of nuclear spin-dependent parity-violating (NSD-PV) effects provide an excellent opportunity to test nuclear models and to search for physics beyond the Standard Model. Molecules possess closely-spaced states with opposite parity which may be easily tuned to degeneracy to greatly enhance the observed parity-violating effects. A high-sensitivity measurement of NSD-PV effects using light triatomic molecules is in preparation [E. B. Norrgard, et al., Commun. Phys. 2, 77 (2019)]. Importantly, by comparing these measurements in light nuclei with prior and ongoing measurements in heavier systems, the contribution to NSD-PV from $Z^{0}$ -boson exchange between the electrons and the nuclei may be separated from the contribution of the nuclear anapole moment. Furthermore, light triatomic molecules offer the possibility to search for new particles, such as the postulated $Z^{'}$ boson. In this work, we detail a sensitive measurement scheme and present high-accuracy molecular and nuclear calculations needed for interpretation of NSD-PV experiments on triatomic molecules composed of light elements Be, Mg, N, and C. The ab initio nuclear structure calculations, performed within the No-Core Shell Model (NCSM) provide a reliable prediction of the magnitude of different contributions to the NSD-PV effects in the four nuclei. These results differ significantly from the predictions of the standard single-particle model and highlight the importance of including many-body effects in such calculations. In order to extract the NSD-PV contributions from measurements, a parity-violating interaction parameter $W_{PV}$ , which depends on molecular structure, needs to be known with high accuracy. We have calculated these parameters for the triatomic molecules of interest using the relativistic coupled-cluster approach.
↳ physics.atom-phhep-phnucl-thPRA(2020)·35 citations
14
Comment on "Tidal Love numbers of neutron and self-bound quark stars"
János Takátsy🇭🇺 · Péter Kovács🇭🇺
We comment on the paper of S. Postnikov et al. in Phys. Rev. D 82, 024016 (2010) and give a modified formula that needs to be taken into account when calculating the tidal Love number of neutron stars in case a first order phase-transition occurs at non-zero pressure. We show that the error made when using the original formula tends to zero as $p \to 0$ and we estimate the maximum relative error to be $\sim 5%$ if the density discontinuity is at larger densities.
↳ astro-ph.HEgr-qcnucl-thPRD(2020)·48 citations
15
Peaks within peaks and the possible two-peak structure of the Pc(4457): the effective field theory perspective
Fang-Zheng Peng🇨🇳 · Jun-Xu Lu🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Mao-Jun Yan🇨🇳 · Manuel Pavon Valderrama🇨🇳
The LHCb pentaquarks -- the $P_{c} (4312)$ , $P_{c} (4440)$ and $P_{c} (4457)$ -- have been theorized to be $Σ_{c} D ˉ$ and $Σ_{c} D ˉ^{*}$ S-wave molecules. Here we explore the possibility that two of these pentaquarks -- the $P_{c} (4440)$ and $P_{c} (4457)$ -- contain in addition a $Λ_{c} (2595) D ˉ$ component in P-wave. We will analyze the effects of this extra channel within two effective field theories: the first one will be a standard contact-range effective field theory and the second one will include the non-diagonal pion dynamics connecting the $Σ_{c} D ˉ^{*}$ and $Λ_{c} (2595) D ˉ$ channels, which happens to be unusually long-ranged. The impact of the coupled-channel dynamics between the $Σ_{c} D ˉ^{*}$ and $Λ_{c} (2595) D ˉ$ components is modest at best for the $P_{c} (4440)$ and $P_{c} (4457)$ , which will remain to be predominantly $Σ_{c} D ˉ^{*}$ molecules. However, if the quantum numbers of the $P_{c} (4457)$ are $J^{P} = \frac{1}{2}^{-}$ , the coupled-channel dynamics is likely to induce the binding of a $Λ_{c} (2595) D ˉ$ S-wave molecule (coupled to $Σ_{c} D ˉ^{*}$ in P-wave) with $J^{P} = \frac{1}{2}^{+}$ and a mass similar to the $P_{c} (4457)$ . If this is the case, the $P_{c} (4457)$ could actually be a double peak containing two different pentaquark states.
↳ hep-phhep-exnucl-thPRD(2021)·26 citations

Affiliations

first authorsco-authorsvia INSPIRE