Mon·Sep 9, 2019Monday·September 9, 2019

1. 01*

   Probing Majorana neutrinos with double-$\beta$ decay

   GERDA collaboration: M. Agostini🇬🇧 · A.M. Bakalyarov🇷🇺 · M. Balata🇮🇹 · I. Barabanov🇷🇺 · L. Baudis🇨🇭 · C. Bauer🇩🇪 · E. Bellotti🇮🇹 · S. Belogurov🇷🇺 · A. Bettini🇮🇹 · L. Bezrukov🇷🇺 · D. Borowicz🇷🇺 · V. Brudanin🇷🇺 and 101 other authors

   A discovery that neutrinos are not the usual Dirac but Majorana fermions, i.e. identical to their antiparticles, would be a manifestation of new physics with profound implications for particle physics and cosmology. Majorana neutrinos would generate neutrinoless double-$\beta$ ($0\nu \beta \beta$) decay, a matter-creating process without the balancing emission of antimatter. So far, 0$\nu \beta \beta$ decay has eluded detection. The GERDA collaboration searches for the $0\nu \beta \beta$ decay of ${}^{76}$Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg$\cdot$yr, we observe no signal and derive a lower half-life limit of T${}_{1/2}$ > 0.9$\cdot$10${}^{26}$ yr (90% C.L.). Our T${}_{1/2}$ sensitivity assuming no signal is 1.1$\cdot$10${}^{26}$ yr. Combining the latter with those from other $0\nu \beta \beta$ decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 - 0.16 eV, with corresponding sensitivities to the absolute mass scale in $\beta$ decay of 0.15 - 0.44 eV, and to the cosmological relevant sum of neutrino masses of 0.46 - 1.3 eV.

   ↳ hep-exnucl-exScience(2019)·186 citations
2. 02*

   Study of QCD dynamics using small systems

   Suman Deb🇮🇳 · Golam Sarwar🇮🇳 · Raghunath Sahoo🇮🇳 · Jan-e Alam🇮🇳

   The multiplicity, finite system size and collision energy dependencies of heat capacity ($C_V$), conformal symmetry breaking measure (CSBM) and speed of sound ($c_s$) have been investigated using ALICE data for $p+p$ collisions at $\sqrt{s}$ = 7 TeV. The aim of this study is to ascertain the possibility of formation of a thermalized medium in such collisions. We find that there is a threshold in charged particle multiplicity beyond which $C_V$, CSBM and $c_s$ attain plateau. The presence of such threshold in multiplicity is further reflected in the variation of these quantities with center-of-mass energy ($\sqrt{s_{NN}}$). In order to have a grasp on experimentally obtained results, variation of $⟨p_T⟩$ with multiplicity has also been studied. The experimental results have been contrasted with PYTHIA8 and it is found that PYTHIA8 is inadequate to explain the features reflected in these quantities, thereby indicating the possibility of thermalization in such small system. It is also observed that the finite size effects alone cannot explain the non-extensive nature of particle spectra in $p+p$ collisions.

   ↳ hep-phnucl-exnucl-thEPJA(2021)·16 citations
3. 03*

   The CUPID-Mo experiment for neutrinoless double-beta decay: performance and prospects

   E. Armengaud🇫🇷 · C. Augier🇫🇷 · A. S. Barabash🇷🇺 · F. Bellini🇮🇹 · G. Benato🇺🇸 · A. Benoît · M. Beretta🇮🇹 · L. Bergé🇫🇷 · J. Billard🇫🇷 · Yu. A. Borovlev🇷🇺 · Ch. Bourgeois🇫🇷 · M. Briere🇫🇷 and 77 other authors

   CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay ($0\nu \beta \beta$) of ${}^{100}$Mo. In this article, we detail the CUPID-Mo detector concept, assembly, installation in the underground laboratory in Modane in 2018, and provide results from the first datasets. The demonstrator consists of an array of 20 scintillating bolometers comprised of ${}^{100}$Mo-enriched 0.2 kg Li${}_2$MoO${}_4$ crystals. The detectors are complemented by 20 thin cryogenic Ge bolometers acting as light detectors to distinguish $\alpha$ from $\gamma$/$\beta$ events by the detection of both heat and scintillation light signals. We observe good detector uniformity, facilitating the operation of a large detector array as well as excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Based on the observed energy resolutions and light yields a separation of $\alpha$ particles at much better than 99.9\% with equally high acceptance for $\gamma$/$\beta$ events is expected for events in the region of interest for ${}^{100}$Mo $0\nu \beta \beta$. We present limits on the crystals' radiopurity ($\le$3 $\mu$Bq/kg of ${}^{226}$Ra and $\le$2 $\mu$Bq/kg of ${}^{232}$Th). Based on these initial results we also discuss a sensitivity study for the science reach of the CUPID-Mo experiment, in particular, the ability to set the most stringent half-life limit on the ${}^{100}$Mo $0\nu \beta \beta$ decay after half a year of livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology - developed in the framework of the LUMINEU project - selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale cryogenic $0\nu \beta \beta$ experiment.

   ↳ physics.ins-dethep-exnucl-exEPJC(2020)·117 citations
4. 04*

   Measurements of jet fragmentation and jet substructure with ALICE

   Markus Fasel (ORNL, for the ALICE Collaboration)🇺🇸

   We discuss the latest results from jet fragmentation and jet substructure measurements performed with the ALICE experiment in proton-proton and heavy-ion collisions in a wide range of jet transverse momentum. The jet production cross sections and cross section ratios for different jet resolution parameters will be shown in a wide range of $p_{\text{T}}$. Results will be compared to next-to-leading order pQCD calculations.

   ↳ hep-exnucl-exPoS(2019)·1 citation

* 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.