Mon·Jan 27, 2020Monday·January 27, 2020

1. 01*

   Shape coexistence in the neutron-deficient ${}^{188}$Hg investigated via lifetime measurements

   M. Siciliano🇮🇹 · I. Zanon🇮🇹 · A. Goasduff🇮🇹 · P.R. John🇮🇹 · T.R. Rodríguez🇪🇸 · S. Péru🇫🇷 · I. Deloncle🇫🇷 · J. Libert🇫🇷 · M. Zielińska🇫🇷 · D. Ashad🇮🇹 · D. Bazzacco🇮🇹 · G. Benzoni🇮🇹 and 32 other authors

   Shape coexistence in the $Z\approx 82$ region has been established in mercury, lead and polonium isotopes. Even-even mercury isotopes with $100\le N\le 106$ present multiple fingerprints of this phenomenon, which seems to be no longer present for $N\ge 110$. According to a number of theoretical calculations, shape coexistence is predicted in the ${}^{188}$Hg isotope. The ${}^{188}$Hg nucleus was populated using two different fusion-evaporation reactions with two targets, ${}^{158}$Gd and ${}^{160}$Gd, and a beam of ${}^{34}$S, provided by the Tandem-ALPI accelerators complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the $\gamma$ rays were detected using the GALILEO $\gamma$-ray array. The lifetimes of the excited states were determined using the Recoil Distance Doppler-Shift method, employing the dedicated GALILEO plunger device. Using the two-bands mixing and rotational models, the deformation of the pure configurations was obtained from the experimental results. The extracted transition strengths were compared with those calculated with the state-of-the-art symmetry-conserving configuration-mixing (SCCM) and five-dimentional collective Hamiltonian (5DCH) approaches in order to shed light on the nature of the observed structures in the ${}^{188}$Hg nucleus. An oblate, a normal- and a super-deformed prolate bands were predicted and their underlying shell structure was also discussed.

   nucl-exnucl-thPRC(2020)·25 citations
2. 02*

   Dynamics of critical fluctuations: Theory -- phenomenology -- heavy-ion collisions

   M. Bluhm🇫🇷 · M. Nahrgang🇫🇷 · A. Kalweit🇨🇭 · M. Arslandok🇩🇪 · P. Braun-Munzinger🇩🇪 · S. Floerchinger🇩🇪 · E.S. Fraga🇧🇷 · M. Gazdzicki🇩🇪 · C. Hartnack🇫🇷 · C. Herold🇹🇭 · R. Holzmann🇩🇪 · Iu. Karpenko🇫🇷 and 18 other authors

   This report summarizes the presentations and discussions during the Rapid Reaction Task Force "Dynamics of critical fluctuations: Theory -- phenomenology -- heavy-ion collisions", which was organized by the ExtreMe Matter Institute EMMI and held at GSI, Darmstadt, Germany in April 2019. We address the current understanding of the dynamics of critical fluctuations in QCD and their measurement in heavy-ion collision experiments. In addition, we outline what might be learned from studying correlations in other physical systems, such as cold atomic gases.

   ↳ nucl-thhep-phnucl-exNPA(2020)·127 citations
3. 03*

   Comparative analysis of $\omega p$, $\varphi p$, and $J/\psi p$ scattering lengths from A2, CLAS, and GlueX threshold measurements

   Igor Strakovsky (GWU)🇺🇸 · Lubomir Pentchev (JLab)🇺🇸 · Alexander Titov (JINR)🇷🇺

   The high accuracy $\varphi$-meson photoproduction data from the CLAS experiment in Hall~B of Jefferson Laboratory allow us to determine the near-threshold total cross section of the $\gamma p\to \varphi p$ reaction and use it for evaluating the $\varphi p$ scattering length ${\alpha }_{\varphi p}$. These data result in an absolute value of $|{\alpha }_{\varphi p}|=(0.063\pm 0.010)$~fm, which is smaller than the typical hadron size. A comparative analysis of ${\alpha }_{\varphi p}$ with the previously determined scattering lengths for $\omega p$ and $J/\psi p$ from the A2 and GlueX experiments is performed.

   ↳ hep-phhep-exnucl-exnucl-thPRC(2020)·57 citations
4. 04*

   Peculiarity of the ${}^{12}$C$(0^{+})$ and ${}^{12}$C$(2^{+})$ energy spectrum in a 3$\alpha$ model

   E.M. Tursunov · I. Mazumdar

   Lowest energy spectrum of the ${}^{12}$C nucleus is analyzed in the 3$\alpha$ cluster model with a deep $\alpha \alpha$-potential of Buck, Friedrich and Wheatley with Pauli forbidden states in the $S$ and $D$ waves. The direct orthogonalization method is applied for the elimination of the 3$\alpha$-Pauli forbidden states. The effects of possible first order quantum phase transition are shown in the lowest ${}^{12}$C($0_1^{+})$ and ${}^{12}$C($2_1^{+})$ states from weakly bound phase to a deep phase. The ground and lowest $2^{+}$ states of the ${}^{12}$C nucleus in the deep phase are created by the critical eigen states of the Pauli projector for the $0^{+}$ and $2^{+}$ three-alpha functional spaces, respectively.

   ↳ nucl-thnucl-exPhys.Atom.Nucl.(2022)·10 citations
5. 05*

   Latest results on the production of hadronic resonances in ALICE at the LHC

   Arvind Khuntia (for the ALICE Collaboration)🇵🇱

   Measurement of short-lived hadronic resonances are used to study different aspects of particle production and collision dynamics in pp, p-A and relativistic heavy-ion collisions. The yields of resonances are sensitive to the competing processes of hadron rescattering and regeneration, thus making these particles unique probes of the properties of the late hadronic phase. Measurements of resonances with different masses and quantum numbers also provide insight into strangeness production and processes that determine the shapes of particle momentum spectra at intermediate transverse momenta, as well as the species dependence of hadron suppression at high momentum. We present the comprehensive set of results in the ALICE experiment with unprecedented precision for $\rho (770{)}^0$, K${}^{\ast }(892)$, $\varphi (1020)$, $\Sigma (1385{)}^{\pm }$, $\Lambda (1520)$, and $\Xi (1530{)}^0$ production in pp, p-Pb, Xe-Xe and Pb-Pb collisions in the energy range $\sqrt{s_{\mathrm{NN}}}$ = 2.76-13 TeV, including the latest measurements from LHC Run 2. The obtained results are used to study the system-size and collision-energy evolution of transverse momentum spectra, particle ratios and nuclear modification factors and to search for the onset of collectivity in small collision systems. We compare these results to lower energy measurements and model calculations where available.

   ↳ hep-exnucl-exNPA(2021)·5 citations
6. 06*

   Parity- and time-reversal-violating nuclear forces

   J. de Vries🇺🇸 · E. Epelbaum🇩🇪 · L. Girlanda🇮🇹 · A. Gnech🇮🇹 · E. Mereghetti🇺🇸 · M. Viviani🇮🇹

   Parity-violating and time-reversal conserving (PVTC) and parity-violating and time-reversal-violating (PVTV) forces in nuclei form only a tiny component of the total interaction between nucleons. The study of these tiny forces can nevertheless be of extreme interest because they allow to obtain information on fundamental symmetries using nuclear systems. The PVTC interaction derives from the weak interaction between the quarks inside nucleons and nuclei and the study of PVTC effects opens a window on the quark-quark weak interaction. The PVTV interaction is sensitive to more exotic interactions at the fundamental level, in particular to strong CP violation in the Standard Model Lagrangian, or even to exotic phenomena predicted in various beyond-the-Standard-Model scenarios. The presence of these interactions can be revealed either by studying various asymmetries in polarized scattering of nuclear systems, or by measuring the presence of non-vanishing permanent electric dipole moments of nucleons, nuclei and diamagnetic atoms and molecules. In this contribution, we review the derivation of the nuclear PVTC and PVTV interactions within various frameworks. We focus in particular on the application of chiral effective field theory, which allows for a more strict connection with the fundamental interactions at the quark level. We investigate PVTC and PVTV effects induced by these potential on several few-nucleon observables, such as the longitudinal asymmetry in proton-proton scattering and radiative neutron-proton capture, and the electric dipole momentsof the deuteron and the trinucleon system.

   ↳ nucl-thhep-phnucl-exFront.in Phys.(2020)·55 citations
7. 07*

   Measuring intensity interference in a low multiplicity system $\pi \pi x$ with a new observing method

   Q. He🇯🇵 · X. He🇨🇳 · T. Li🇨🇳

   Prior proposed observing approaches using event mixing technique for Bose-Einstein correlations (BEC) measurements in exclusive reactions with very low multiplicities are still unsatisfactory due to the problems of sample reduction and introducing extra and unnecessary fitting parameters. We here propose an event mixing method with a new mixing cut, named energy sum range (ESR) cut, to investigate two-pion Bose-Einstein correlations (BEC) in reactions with only two identical pions among three final state particles. This mixing method employs two-pion energy sum characteristic to control the mixing procedures, with no requirement on eliminating any original events. Numerical simulations are performed to show the viability of this new BEC observing method.

   ↳ nucl-thhep-exnucl-exActa Phys.Polon.B(2020)·1 citation
8. 08*

   Slow Fluors for Effective Separation of Cherenkov Light in Liquid Scintillators

   Steven D. Biller🇬🇧 · Edward J. Leming🇬🇧 · Josephine L. Paton🇬🇧

   The timing and spectral characteristics of four highly efficient, slow fluors are presented for liquid scintillator solutions using linear alkylbenzene (LAB) as the primary solvent. The mixtures exhibit high light yields, but with rise times of several ns or more and decay times on the order of tens of ns. Consequently, such liquid scintillator mixtures can be used for effective separation of Cherenkov and scintillation components based on timing in large scale liquid scintillation detectors. Such a separation, showing high light yield and directional information, is demonstrated here on a bench-top scale for electrons with energies extending below 1 MeV. This could have significant consequences for the future development of such detectors for measurements of solar neutrinos and neutrinoless double beta decay as well as providing good directional information for elastic scattering events from supernovae neutrinos and reactor anti-neutrinos, amongst others.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2020)·48 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.