Fri·Apr 30, 2021Friday·April 30, 2021

1. 01*

   The Lowest Broad Alpha Cluster Resonances in ${}^{19}$F

   A. Volya🇺🇸 · V. Z. Goldberg🇺🇸 · A. K. Nurmukhanbetova🇰🇿 · D. K. Nauruzbayev🇰🇿 · G. V. Rogachev🇺🇸

   There is a deep astrophysical interest in the structure of ${}^{19}$F states close to the alpha decay threshold. The nuclear structure of these states is important for understanding of the development of $\alpha$ clustering in the ${}^{20}$Ne region. Emergence of clustered states and generally states that favor coupling to reaction channels near the corresponding decay thresholds is currently of special interest in theoretical physics. Excitation function for ${}^{15}$N($\alpha$,$\alpha$) elastic scattering was measured by the TTIK method. These new data together with old, high energy resolution data, were analyzed using the R matrix approach. ${}^{19}$F nuclear structure was calculated using configuration interaction methods with the recently developed effective interaction Hamiltonian. The parameters of broad low spin $\ell =0$ and 1 relative partial wave resonances close to the $\alpha$ decay threshold in ${}^{19}$F were identified. Detailed theoretical analysis was carried out identifying all states coupled to the $\ell =0$ and 1 alpha cluster channels. Considering hierarchy of states with different harmonic oscillator shell excitations allows to evaluate coupling to the alpha channels with different number of nodes in the relative wave function and helps to explain the distribution of the clustering strength and emergence of broad clustering resonances. Comparison of clustering in ${}^{20}$Ne into ${}^{16}$O+$\alpha$ and consideration of spin-orbit splitting of the ${}^{15}$N+$\alpha$ channel provides additional evidence. Detailed analysis of new and old experimental data allows to identify a series of $\alpha$ clustering resonances in ${}^{19}$F and to assess the distribution of the clustering strength which is of importance to questions of astrophysics and for theoretical understanding of many-body physics and emergence of clustering in loosely bound or unstable nuclei.

   nucl-exnucl-thPRC(2022)·9 citations
2. 02*

   Survival probabilities of charmonia as a clue to measure transient magnetic fields

   Sachio Iwasaki🇯🇵 · Daisuke Jido🇯🇵 · Makoto Oka🇯🇵 · Kei Suzuki🇯🇵

   We investigate time evolution of $S$-wave charmonium populations under a time-dependent homogeneous magnetic field and evaluate survival probabilities of the low-lying charmonia to the goal of estimating the magnetic field strength at heavy-ion collisions. Our approach implements mixing between different spin eigenstates and transitions to radially excited states. We show that the survival probabilities can change even by an extremely short magnetic field. Furthermore, we find that the survival probabilities depend on the initial spin states. We propose the sum of the survival probabilities over spin partners as an observable insensitive to the initial states. We also find that the sum can be approximately given as a function of $\sigma B_0^2$ with a duration time $\sigma$ and the maximum strength of the magnetic field $B_0$.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2021)·9 citations
3. 03*

   A review of quarkonia under strong magnetic fields

   Sachio Iwasaki🇯🇵 · Makoto Oka🇯🇵 · Kei Suzuki🇯🇵

   We review the properties of quarkonia under strong magnetic fields. The main phenomena are (i) mixing between different spin eigenstates, (ii) quark Landau levels and deformation of wave function, (iii) modification of $\bar{Q}Q$ potential, and (iv) the motional Stark effect. For theoretical approaches, we review (i) constituent quark models, (ii) effective Lagrangians, (iii) QCD sum rules, and (iv) holographic approaches.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJA(2021)·46 citations
4. 04*

   Unveiling the pole structure of S-matrix using deep learning

   Denny Lane B. Sombillo🇵🇭 · Yoichi Ikeda🇯🇵 · Toru Sato🇯🇵 · Atsushi Hosaka🇯🇵

   Particle scattering is a powerful tool to unveil the nature of various subatomic phenomena. The key quantity is the scattering amplitude whose analytic structure carries the information of the quantum states. In this work, we demonstrate our first step attempt to extract the pole configuration of inelastic scatterings using the deep learning method. Among various problems, motivated by the recent new hadron phenomena, we develop a curriculum learning method of deep neural network to analyze coupled channel scattering problems. We show how effectively the method works to extract the pole configuration associated with resonances in the $\pi N$ scatterings.

   ↳ hep-phhep-exnucl-exnucl-th+1Rev.Mex.Fis.Suppl.(2022)·10 citations
5. 05*

   Initial- and final-state temperatures of emission source from differential cross-section in squared momentum transfer in high energy collisions

   Qi Wang🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿

   The differential cross-section in squared momentum transfer of $\rho$, ${\rho }^0$, $\omega$, $\varphi$, $f_0(980)$, $f_1(1285)$, $f_0(1370)$, $f_1(1420)$, $f_0(1500)$, and $J/\psi$ produced in high energy virtual photon-proton ($\gamma$${}^{\ast }p$), photon-proton ($\gamma p$), and proton-proton ($pp$) collisions measured by the H1, ZEUS, and WA102 Collaborations are analyzed by the Monte Carlo calculations. In the calculations, the Erlang distribution, Tsallis distribution, and Hagedorn function are separately used to describe the transverse momentum spectra of the emitted particles. Our results show that the initial- and final-state temperatures increase from lower squared photon virtuality to higher one, and decrease with increasing of center-of-mass energy.

   ↳ hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2021)·12 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.