Fri·Aug 14, 2020Friday·August 14, 2020

1. 01*

   The Majorana Demonstrator's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se

   I.J. Arnquist🇺🇸 · F.T. Avignone III🇺🇸 · A.S. Barabash🇷🇺 · C.J. Barton🇺🇸 · F.E. Bertrand🇺🇸 · E. Blalock🇺🇸 · B. Bos🇺🇸 · M. Busch🇺🇸 · M. Buuck🇺🇸 · T.S. Caldwell🇺🇸 · Y-D. Chan🇺🇸 · C.D. Christofferson🇺🇸 and 51 other authors

   The Majorana Demonstrator is a neutrinoless double-beta decay search consisting of a low-background modular array of high-purity germanium detectors, $\sim 2/3$ of which are enriched to 88\% in ${}^{76}$Ge. The experiment is also searching for double-beta decay of ${}^{76}$Ge to excited states (e.s.) in ${}^{76}$Se. ${}^{76}$Ge can decay into three daughter states of ${}^{76}$Se, with clear event signatures consisting of a $\beta \beta$-decay followed by the prompt emission of one or two $\gamma$-rays. This results with high probability in multi-detector coincidences. The granularity of the Demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9~kg-y of isotopic exposure, the Demonstrator has set world leading limits for each e.s.\ decay of ${}^{76}$Ge, with 90\% CL lower half-life limits in the range of $(0.75-4.0)\times 10^{24}$~y. In particular, for the $2\nu$ transition to the first $0^{+}$ e.s.\ of ${}^{76}$Se, a lower half-life limit of $7.5\times 10^{23}$~y at 90\% CL was achieved.

   nucl-exPRC(2021)·24 citations
2. 02*

   Comment on: "The interaction of neutrons with 7Be at BBN temperatures: Lack of Standard Nuclear Solution to the Primordial 7Li Problem" by M. Gai et al

   M. Paul🇮🇱 · R. Dressler🇨🇭 · U. Koester🇫🇷 · D. Schumann🇨🇭

   The article recently published by M. Gai et al. claims to reach conclusions from a collaborative experiment dedicated to the study of the 7Be(n,alpha) reaction. These claims were published with no authorization from key collaborators, including a PI of the experiment. The Authors of the present Comment reject the conclusions of M. Gai et et al. and condemn the scientific and ethical misconduct involved in their publication. A formal Comment, similarly expressing the Authors' rejection of these conclusions was submitted to EPJ Web of Conferences who published the above article.

   nucl-ex1 citation
3. 03*

   Defect behavior and radiation tolerance of MAB phases (MoAlB and Fe2AlB2) with comparison to MAX phases

   Hongliang Zhang · JunYoung Kim🇰🇷 · Ranran Su · Peter Richardson🇬🇧 · Jianqi Xi · Erich Kisi · John O'Connor · Liqun Shi · Izabela Szlufarska

   MAB phases are a new class of layered ternary materials that have already shown a number of outstanding properties. Here, we investigate defect evolution and radiation tolerance of two MAB phases, MoAlB and Fe2AlB2, using a combination of experimental characterization and first-principles calculations. We find that Fe2AlB2 is more tolerant to radiation-induced amorphization than MoAlB, both at 150 {\deg}C and at 300 {\deg}C. The results can be explained by the fact that the Mo Frenkel pair is unstable in MoAlB and as a result, irradiated MoAlB is expected to have a significant concentration of MoAl antisites, which are difficult to anneal even at 300 {\deg}C. We find that the tolerance to radiation-induced amorphization of MAB phases is lower than in MAX phases, but it is comparable to that of SiC. However, MAB phases do not show radiation-induced cracking which is observed in MAX phases under the same irradiation conditions. This study suggests that MAB phases might be a promising class of materials for applications that involve radiation.

   ↳ cond-mat.mtrl-scinucl-exActa Mater.(2020)·0 citations
4. 04*

   Dynamical grooming at work: from p+p to Pb+Pb

   Alba Soto-Ontoso🇺🇸

   We present a quantitative comparison between two grooming techniques: SoftDrop (SD) and Dynamical Grooming (DyG), in terms of the resilience of their associated observables to the underlying event, hadronization and pileup in proton-proton collisions at $\sqrt{s}=13$ TeV. For that purpose, we study the groomed momentum fraction, $z_g$, in QCD jets along with boosted W tagging. In addition, we obtain the groomed momentum angle, $R_g$, within several jet quenching Monte-Carlo models in order to asses the sensitivity of SD and DyG observables to quark-gluon plasma (QGP) effects in heavy-ion collisions.

   ↳ hep-phhep-exnucl-exPoS(2021)·4 citations
5. 05*

   Recent quarkonium measurements in small systems with the ALICE detector at the LHC

   Manuel Guittière (on behalf of the ALICE Collaboration)🇫🇷

   At the LHC collision energies, multiple parton interactions (MPI) are a key ingredient for particle production models including hard scale processes like heavy-quark production (charm and beauty). Quarkonium measurements in high-multiplicity proton-proton (pp) collisions can shed light on the role of MPI at such hard momentum scales, as well as on the interplay between hard and soft particle production mechanisms. In addition, quarkonium production measurements in minimum bias pp collisions, besides serving as a reference for heavy-ion collisions collected at the same center-of-mass energy, represent a benchmark test of various QCD based models. In this contribution, the latest quarkonium measurements performed by the ALICE collaboration in pp collisions at several center-of-mass energies are presented. A comprehensive study of the multiplicity dependence of the quarkonium production at $\sqrt{s}=13$ TeV, based on minimum bias and high-multiplicity triggered events, is also presented. Such measurements include $\psi$(2S) production at forward rapidity as a function of the charged particle multiplicity density, as well as the latest multiplicity dependent inclusive J/$\psi$ production measurements at midrapidity, based on multiplicity estimators covering different pseudorapidity regions. Similar multiplicity dependent measurements in p--Pb collisions at center-of-mass energies of $\sqrt{s_{\mathrm{NN}}}=$ 5.02 and 8.16 TeV are also presented. The reported results are compared with available theoretical model calculations.

   ↳ hep-exnucl-exPoS(2021)·1 citation
6. 06*

   Particle Production in AgAg Collisions at $E_{\mathrm{Kin}}=1.58A$ GeV within a Hadronic Transport Approach

   Jan Staudenmaier🇩🇪 · Natey Kübler🇩🇪 · Hannah Elfner🇩🇪

   Heavy-ion collisions at low beam energies explore the high density regime of strongly-interacting matter. The dynamical evolution of these collisions can be successfully described by hadronic transport approaches. In March 2019, the HADES collaboration has taken data for AgAg collisions at $E_{\mathrm{Kin}}=1.58A$ GeV and in this work, we provide predictions for particle production and spectra within the Simulating Many Accelerated Strongly-interacting Hadrons (SMASH) approach. The multiplicities and spectra of strange and non-strange particles follow the expected trends as a function of system size. In particular, in AuAu collisions, much higher yields of double-strange baryons were observed experimentally than expected from a thermal model. Therefore, we incorporate a previously suggested mechanism to produce $\Xi$ baryons via rare decays of high mass $N^{\ast }$ resonances and predict the multiplicities. In addition, we predict the invariant mass spectrum for dilepton emission and explore the most important sources of dileptons above 1 GeV, that are expected to indicate the temperature of the medium. Interestingly, the overall dilepton emission is very similar to the one in AuAu collisions at $1.23A$ GeV, a hint that the smaller system at a higher energy behaves very similar to the larger system at lower beam energy.

   ↳ hep-phnucl-exnucl-thPRC(2021)·12 citations
7. 07*

   Simulating core excitation in breakup reactions of halo nuclei using an effective three-body force

   P. Capel🇧🇪 · D. R. Phillips🇺🇸 · H.-W. Hammer🇩🇪

   We extend our previous calculation of the breakup of 11Be using Halo Effective Field Theory and the Dynamical Eikonal Approximation to include an effective 10Be-n-target force. The force is constructed to account for the virtual excitation of 10Be to its low-lying 2+ excited state. In the case of breakup on a 12C target this improves the description of the neutron-energy and angular spectra, especially in the vicinity of the 11Be 5/2+ state. By fine-tuning the range parameters of the three-body force, a reasonable description of data in the region of the 3/2+ 11Be state can also be obtained. This sensitivity to the three-body force's range results from the structure of the overlap integral that governs the 11Be s-to-d-state transitions induced by the three-body force.

   ↳ nucl-thnucl-exPLB(2022)·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.