Tue·Oct 26, 2021Tuesday·October 26, 2021

1. 01*

   A global study of ${}^9$Be + p at 2.72 A MeV

   V. Soukeras🇮🇹 · O. Sgouros🇮🇹 · A. Pakou🇬🇷 · F. Cappuzzello🇮🇹 · J. Casal🇪🇸 · C. Agodi🇮🇹 · G. A. Brischetto🇮🇹 · S. Calabrese🇮🇹 · D. Carbone🇮🇹 · M. Cavallaro🇮🇹 · I. Ciraldo🇮🇹 · I. Dimitropoulos🇬🇷 and 8 other authors

   Background: In our recent experiment, ${}^9$Be+p at 5.67A MeV, the breakup decay rates to the 3 configurations, $\alpha$+$\alpha$+n, ${}^8$Be${}^{\ast }$+n and ${}^5$He+${}^4$He of ${}^9$Be, were observed and quantified, in a full kinematics approach. Unfolding step by step the accessibility to the above configurations, it will require similar studies at lower and higher energies as well as the interpretation of the data in a theoretical framework. Purpose: Investigate the breakup decay rate of ${}^9$Be+p at 2.72A MeV, where the $\alpha$+$\alpha$+n configuration is mainly accessible. Compare and interpret data at 2.72A MeV and 5.67A MeV into a 4-body CDCC formalism; Point out and discuss couplings to continuum. Methods: Our experimental method includes an exclusive breakup measurement in a full kinematic approach of ${}^9$Be incident on a proton target at 2.72A MeV, together with elastic scattering and other reaction channels measurements under the same experimental conditions. The interpretation of the data at 2.72A MeV and 5.67A MeV is considered in a 4-body CDCC approach, using the Transformed Harmonic Oscillator method for the 3-body projectile. Results: An elastic scattering angular distribution at 2.72A MeV is measured, which compares very well with CDCC calculations, indicating a strong coupling to continuum. At the same energy, the measured breakup and total reaction cross sections present good agreement with the calculated values. Further on, the elastic scattering and breakup cross section data at 5.67A MeV are found in very good agreement with the CDCC calculations. The present results support further our 3-body model for the structure of ${}^9$Be, validating relevant radiative reaction rates obtained previously.

   nucl-exPRC(2020)·7 citations
2. 02*

   Measurements of heavy-flavor production as a function of multiplicity with ALICE at the LHC

   Yoshini Bailung (on behalf of the ALICE Collaboration)🇮🇳

   In this contribution, the production of heavy-flavor hadrons as a function of multiplicity, via the study of the D-meson and heavy-flavor hadron decay leptons self-normalized yields in pp collisions at the center of mass energy $\sqrt{s}=13$ TeV is discussed. Comparisons are made with similar measurements of J/$\psi$ at $\sqrt{s}=13$ TeV and various model calculations. The ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ and ${\mathrm{D}}_{\mathrm{s}}^{+}/{\mathrm{D}}^0$ yield ratios in different multiplicity intervals in pp collisions at $\sqrt{s}=13$ TeV are also reported. In addition, the ALICE measurement of ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV down to transverse momentum ($p_{\mathrm{T}}$) = 0 GeV/$c$ is presented. Finally, the nuclear modification factor is shown for open charm hadrons at $\sqrt{s}=5.02$ TeV in p-Pb collisions. Finally, measurements of the elliptic flow of heavy-flavor hadron decay leptons in p-Pb systems are presented, which hint towards a possible collective behaviour in high multiplicity p-Pb collisions.

   ↳ hep-exnucl-exSciPost Phys.Proc.(2022)·1 citation
3. 03*

   Optimization of basis functions for the multi-configuration mixing using the Replica Exchange Monte-Carlo method and its application to ${}^{12}$C

   Takatoshi Ichikawa · Naoyuki Itagaki🇯🇵

   To calculate excited states in quantum many-body systems, multi-configuration mixing has often been employed. However, it has been still unclear how to choose important Slater determinants from a huge model space. We propose a novel efficient method as the Replica Exchange Monte-Carlo (RXMC) method to sample important Slater determinants and optimize and analyze the obtained results. As an application, we apply it to the ground and excited states of ${}^{12}$C based on the Bloch-Brink $\alpha$ cluster model and show the detailed structure of the obtained states. The RXMC method enables us to efficiently sample Slater determinants following the Boltzmann distribution on the multi-dimensional potential energy surface (PES) under a given model space. To analyze the obtained excited states, we embed sampled basis functions onto the PES calculated with the $\beta$-$\gamma$ constraint method and discuss the main component in the state. The RXMC method can efficiently perform the samplings with a temperature parameter of $T_L=2.5$ MeV in ${}^{12}$C. We obtain the gas-like state with a wide density distribution in the tail part in the second $0^{+}$ state. We also obtain the linear-chain-like states with the bending and stretching vibrational modes in the third and fourth $0^{+}$ states, respectively. In the fifth $0^{+}$ state, the main component of the basis functions contains expanded equilateral triangle configurations. The second $0^{+}$ gas-like state emerges at the local minimum in the PES, which is the beginning of the valley structure connected to the linear-chain breakup channel. The third and fourth linear-chain-like states emerge in this valley structure. We conclude that the RXMC method is a powerful method to calculate the excited states of nuclei, which would be applied to much complicated nuclear fission dynamics in heavier nuclei.

   ↳ nucl-thnucl-exPRC(2022)·10 citations
4. 04*

   An upgraded focal plane detector for the MAGNEX spectrometer

   D. Torresi · O. Sgouros🇮🇹 · V. Soukeras🇮🇹 · M. Cavallaro🇮🇹 · F. Cappuzzello🇮🇹 · D. Carbone🇮🇹 · C. Agodi🇮🇹 · G. A. Brischetto🇮🇹 · S. Calabrese🇮🇹 · I. Ciraldo🇮🇹 · N. Deshmukh🇮🇹 · A. Hacisalihoglu🇹🇷 · L. La Fauci🇮🇹 · A. Spatafora🇮🇹

   An upgraded and improved version of the focal plane detector (FPD) of the large-acceptance magnetic spectrometer MAGNEX is described here. The FPD consists of a tracker operating at low pressure and of a silicon detector wall. Thanks to a different geometry of the electron multiplication and induction elements, the new detector guarantees a superior signal to noise ratio, resulting in a more accurate tracking and a cleaner identification of the detected heavy ions. The new detector has been tested by using a ${}^{18}$O beam at an energy of 84 MeV. A description of the new FPD that pinpoints the innovation and the obtained performances is given and discussed in details.

   ↳ physics.ins-detnucl-ex0 citations
5. 05*

   Ultracold neutron storage and transport at the PSI UCN source

   G. Bison (1)🇨🇭 · M. Daum (1)🇨🇭 · K. Kirch (1,2)🇨🇭 · B. Lauss (1)🇨🇭 · D. Ries (3)🇩🇪 · P. Schmidt-Wellenburg (1)🇨🇭 · G. Zsigmond (1) ((1) Laboratory for Particle Physics, Paul Scherrer Institut, Switzerland, (2) Institute for Particle Physics, ETH Zürich, Zürich, Switzerland, (3) Department of Chemistry - TRIGA site, Johannes Gutenberg University Mainz, Mainz, Germany)🇨🇭

   Efficient neutron transport is a key ingredient to the performance of ultracold neutron (UCN) sources, important to meeting the challenges placed by high precision fundamental physics experiments. At the Paul Scherrer Institute's UCN source we have been continuously improving our understanding of the UCN source parameters by performing a series of studies to characterize neutron production and moderation, and UCN production, extraction, and transport efficiency to the beamport. The present study on the absolute UCN transport efficiency completes our previous publications. We report on complementary measurements, namely one on the height-dependent UCN density and a second on the transmission of a calibrated quantity of UCN over a ~16 m long UCN guide section connecting one beamport via the source storage vessel to another beamport. These allow us quantifying and optimizing the performance of the guide system based on extensive Monte Carlo simulations.

   ↳ physics.ins-detnucl-exEPJA(2022)·16 citations
6. 06*

   Analysis of the background on cross section measurements with the MAGNEX spectrometer: the (20Ne,20O) Double Charge Exchange case

   S. Calabrese🇮🇹 · F. Cappuzzello🇮🇹 · D. Carbone🇮🇹 · M. Cavallaro🇮🇹 · C. Agodi🇮🇹 · D. Torresi · L. Acosta🇲🇽 · D. Bonanno🇮🇹 · D. Bongiovanni🇮🇹 · T. Borello-Lewin🇧🇷 · I. Boztosun🇹🇷 · G. A. Brischetto🇮🇹 and 31 other authors

   The MAGNEX magnetic spectrometer is used in the experimental measurements of Double Charge Exchange and Multi-Nucleon Transfer reactions induced by heavy ions within the NUMEN project. These processes are characterized by small cross sections under a large background due to other reaction channels. Therefore an accurate control of the signal to background ratio is mandatory. In this article, the determination of the MAGNEX spectrometer background contribution on cross section measurements is presented by applying a suitable analysis to quantify the limits of the adopted particle identification technique. The method is discussed considering the 116Cd(20Ne,20O)116Sn Double Charge Exchange reaction data, however it can be applied to any other reaction channel of interest.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·33 citations
7. 07*

   Predictions and postdictions for relativistic lead and oxygen collisions with Trajectum

   Govert Nijs🇺🇸 · Wilke van der Schee🇨🇭

   We introduce a global analysis of relativistic heavy ion collisions using Trajectum of a significantly higher precision and including a new option to vary the normalization of the centrality estimator. We use the posterior distribution of our parameters to generate a set of high statistics samples that allows us to make precise predictions including statistical and systematic uncertainties estimated from the model parameter distribution. The results are systematically compared with experiment whereby we also include many observables not included in the global analysis. This includes in particular (extremely) ultracentral anisotropic flow and mean transverse momentum, whereby we find satisfactory agreement with experiment where data is available. Lastly, we compute spectra and anisotropic flow for oxygen-oxygen collisions performed at RHIC and to be performed at the LHC and comment on how these collisions may inform us on properties of the Quark-Gluon-Plasma.

   ↳ nucl-thhep-phnucl-exPRC(2022)·79 citations
8. 08*

   Neutron-Mirror Neutron oscillations in Matter

   Yuri Kamyshkov🇺🇸 · James Ternullo🇺🇸 · Louis Varriano🇺🇸 · Zurab Berezhiani🇮🇹

   The possibility that a neutron can be transformed to a hidden sector particle remains intriguingly open. Proposed theoretical models conjecture that the hidden sector can be represented by a mirror sector, and the neutron n can oscillate into its sterile mirror twin n', exactly or nearly degenerate in mass with n. Oscillations n - n' can take place in vacuum and in the environment of the regular matter and the magnetic field where only neutron will be subject of interaction with the environment. We describe the propagation of the oscillating n - n' system as a particle of the cold neutron beam passing through the dense absorbing materials in connection with the possible regeneration type of experiments where the effect of n -> n' -> n transformation can be observed.

   ↳ hep-phnucl-exnucl-thSymmetry(2022)·19 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.