Tue·Oct 17, 2017Tuesday·October 17, 2017

1. 01*

   Sensitivity and discovery potential of the proposed nEXO experiment to neutrinoless double beta decay

   nEXO Collaboration: J.B. Albert · G. Anton · I.J. Arnquist · I. Badhrees · P.S. Barbeau · D. Beck · V. Belov · F. Bourque · J.P. Brodsky · E. Brown · T. Brunner · A. Burenkov and 133 other authors

   The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double beta ($0\nu \beta \beta$) decay in ${}^{136}$Xe with a target half-life sensitivity of approximately $10^{28}$ years using $5\times 10^3$ kg of isotopically enriched liquid-xenon in a time projection chamber. This improvement of two orders of magnitude in sensitivity over current limits is obtained by a significant increase of the ${}^{136}$Xe mass, the monolithic and homogeneous configuration of the active medium, and the multi-parameter measurements of the interactions enabled by the time projection chamber. The detector concept and anticipated performance are presented based upon demonstrated realizable background rates.

   nucl-exphysics.ins-detPRC(2018)·309 citations
2. 02*

   Anisotropic flow of identified particles in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   Redmer Alexander Bertens🇺🇸

   Anisotropic flow is sensitive to the shear $(\eta /s)$ and bulk ($\zeta /s$) viscosity of the quark-gluon plasma created in heavy-ion collisions, as well as the initial state of such collisions and hadronization mechanisms. In these proceedings, elliptic ($v_2$) and higher harmonic ($v_3,v_4$) flow coefficients of ${\pi }^{\pm }$, $K^{\pm }$, p$(\overline{\mathrm{p}})$ and the $\varphi$-meson, are presented for Pb-Pb collisions at the highest-ever center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. Comparisons to hydrodynamic calculations (IP-Glasma, MUSIC, UrQMD) are shown to constrain the initial conditions and viscosity of the medium.

   nucl-exhep-exEPJ Web Conf.(2018)·0 citations
3. 03*

   Highlights from STAR heavy ion program

   V.A. Okorokov (on behalf of the STAR Collaboration, National Research Nuclear University MEPhI)🇷🇺

   Recent experimental results obtained in STAR experiment at the Relativistic heavy-ion collider (RHIC) with ion beams will be discussed. Investigations of different nuclear collisions in some recent years focus on two main tasks, namely, detail study of quark-gluon matter properties and exploration of the quantum chromodynamics (QCD) phase diagram. Results at top RHIC energy show clearly the collective behavior of heavy quarks in nucleus-nucleus interactions. Jet and heavy hadron measurements lead to new constraints for energy loss models for various flavors. Heavy-ion collisions are unique tool for the study of topological properties of theory as well as the magneto-hydrodynamics of strongly interacting matter. Experimental results obtained for discrete QCD symmetries at finite temperatures confirm indirectly the topologically non-trivial structure of QCD vacuum. Finite global vorticity observed in non-central Au+Au collisions can be considered as important signature for presence of various chiral effects in sQGP. Most results obtained during stage I of the RHIC beam energy scan (BES) program show smooth behavior vs initial energy. However certain results suggest the transition in the domain of dominance of hadronic degrees of freedom at center-of-mass energies between 10--20 GeV. The stage II of the BES at RHIC will occur in 2019--2020 and will explore with precision measurements in the domain of the QCD phase diagram with high baryon densities. Future developments and more precise studies of features of QCD phase diagram in the framework of stage II of RHIC BES will be briefly discussed.

   nucl-exEPJ Web Conf.(2017)·18 citations
4. 04*

   Spectroscopy of excited states of unbound nuclei ${}^{30}$Ar and ${}^{29}$Cl

   X.-D. Xu🇨🇳 · I. Mukha🇩🇪 · L.V. Grigorenko🇷🇺 · C. Scheidenberger🇩🇪 · L. Acosta🇮🇹 · E. Casarejos🇪🇸 · V. Chudoba🇷🇺 · A.A. Ciemny🇵🇱 · W. Dominik🇵🇱 · J. Duénas-Díaz · V. Dunin🇷🇺 · J. M. Espino🇪🇸 and 36 other authors

   Several states of proton-unbound isotopes ${}^{30}$Ar and ${}^{29}$Cl were investigated by measuring their in-flight decay products, ${}^{28}$S+proton+proton and ${}^{28}$S+proton, respectively. A refined analysis of ${}^{28}$S-proton angular correlations indicates that the ground state of ${}^{30}$Ar is located at $2.45_{-0.10}^{+0.05}$ MeV above the two-proton emission threshold. The theoretical investigation of the ${}^{30}$Ar ground state decay demonstrates that its mechanism has the transition dynamics with a surprisingly strong sensitivity of the correlation patterns of the decay products to the two-proton decay energy of the ${}^{30}$Ar ground state and the one-proton decay energy as well as the one-proton decay width of the ${}^{29}$Cl ground state. The comparison of the experimental ${}^{28}$S-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed ${}^{30}$Ar excited states decay by sequential emission of protons via intermediate resonances in ${}^{29}$Cl. Based on the findings, the decay schemes of the observed states in ${}^{30}$Ar and ${}^{29}$Cl were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously-known states of a two-proton emitter ${}^{19}$Mg were remeasured. Evidences for one new excited state in ${}^{19}$Mg and two unknown states in ${}^{18}$Na were found.

   nucl-exPRC(2018)·17 citations
5. 05*

   Measurement of the D-meson nuclear modification factor and elliptic flow in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$ with ALICE at the LHC

   Fabrizio Grosa (for the ALICE Collaboration)🇮🇹

   Heavy-flavour hadrons are recognised as a powerful probe for the characterisation of the deconfined medium created in heavy-ion collisions, the Quark-Gluon Plasma (QGP). The ALICE Collaboration measured the production of ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast }$ and ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ mesons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$. The measurement of the nuclear modification factor ($R_{\mathrm{AA}}$) provides a strong evidence of the in-medium parton energy loss. The comparison between the ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ and the non-strange D-meson $R_{\mathrm{AA}}$ can help to study the hadronisation mechanism of the charm quark in the QGP. In mid-central collisions, the measurement of the D-meson elliptic flow $v_2$ at low transverse momentum ($p_{\mathrm{T}}$) gives insight into the participation of the charm quark into the collective motion of the system, while at high $p_{\mathrm{T}}$ it constrains the path-length dependence of the energy loss. The ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ $v_2$, measured for the first time at the LHC, is found to be compatible to that of non-strange D mesons and positive with a significance of about $2.6\sigma$. Further evidence of a strong coupling of the charm quark to the light quarks of the underlying medium is suggested by the first application of the Event-Shape Engineering (ESE) technique to D-meson elliptic flow.

   nucl-exEPJ Web Conf.(2018)·4 citations
6. 06*

   Centrality and transverse momentum dependence of $J/\psi$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV at mid-rapidity with ALICE

   Dennis Weiser (for the ALICE collaboration)🇩🇪

   We present new results for the nuclear modification factor \RAA of \jpsi mesons as a function of centrality and transverse momentum at mid-rapidity. The measurement is carried out with the ALICE central barrel detectors in the acceptance range $|y|$ < 0.9 and \pt > 0 in the dielectron decay channel.

   nucl-exEPJ Web Conf.(2018)·5 citations
7. 07*

   Light nuclei production in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV

   Lilin Zhu🇨🇳 · Hua Zheng🇮🇹 · Che Ming Ko🇺🇸 · Yifeng Sun🇺🇸

   Using the coalescence model based on the phase-space distribution of nucleons from an extended blast-wave model that includes the space-momentum correlation of high momentum nucleons, we study the transverse momentum spectra and elliptic flows of deuteron and helium-3 in Pb+Pb collisions at the energy $\sqrt{s_{NN}}=2.76$ TeV. We find that the measured elliptic flows of deuteron can be satisfactorily described if nucleons of large transverse momenta are more spread in space when their momenta are more aligned along the reaction plane.

   ↳ nucl-thnucl-exEPJA(2018)·22 citations
8. 08*

   Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment

   T. M. Ito🇺🇸 · E. R. Adamek🇺🇸 · N. B. Callahan🇺🇸 · J. H. Choi🇺🇸 · S. M. Clayton🇺🇸 · C. Cude-Woods🇺🇸 · S. Currie🇺🇸 · X. Ding🇺🇸 · D. E. Fellers🇺🇸 · P. Geltenbort🇫🇷 · S. K. Lamoreaux🇺🇸 · C. Y. Liu🇺🇸 and 14 other authors

   The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was $184(32)$ UCN/cm${}^3$, a four-fold increase from the highest previously reported. The polarized UCN density stored in an external chamber was measured to be $39(7)$ UCN/cm${}^3$, which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of $\sigma (d_n)=3\times 10^{-27}$ $e\cdot$cm.

   ↳ physics.ins-detnucl-exphysics.acc-phPRC(2018)·95 citations
9. 09*

   News on spectra from the NA61/SHINE experiment

   Magdalena Kuich (for the NA61/SHINE Collaboration)🇵🇱

   NA61/SHINE is a fixed target experiment at the CERN Super-Proton-Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. In order to reach these goals, a study of hadron production properties is performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei. In this talk, recent results on particle production in p+p interactions, as well as Be+Be and Ar+Sc collisions in the SPS energy range are reviewed. Transverse momentum, transverse mass and rapidity spectra obtained with various analysis methods are presented. Surprises in studies of signatures of onset of deconfinement are discussed. The results are compared with available world data.

   ↳ hep-exnucl-exPoS(2017)·0 citations
10. 10*

    Examinations of the consistency of the quasiparticle random-phase approximation approach to double-$\beta$ decay of ${}^{48}$Ca

    J. Terasaki🇨🇿

    The nuclear matrix elements (NMEs) of the neutrinoless and two-neutrino double-$\beta$ decays of ${}^{48}$Ca are calculated by the quasiparticle random-phase approximation (QRPA) with emphasis on the consistency examinations of this calculation method. The main new examination points are the consistency of two ways to treat the intermediate-state energies in the two-neutrino double-$\beta$ NME and comparison with the experimental charge-exchange strength functions obtained from ${}^{48}$Ca$(p,n)$ and ${}^{48}$Ti$(n,p)$ reactions. No decisive problem preventing the QRPA approach is found. The obtained neutrinoless double-$\beta$ NME adjusted by the ratio of the effective and bare axial-vector current couplings is lowest in those calculated by several groups and close to one of the QRPA values obtained by another group.

    ↳ nucl-thnucl-exPRC(2018)·16 citations
11. 11*

    Time calibration of the J-PET detector

    M. Skurzok🇵🇱 · M. Silarski🇵🇱 · D. Alfs🇵🇱 · P. Bialas🇵🇱 · Shivani · C. Curceanu🇮🇹 · E. Czerwinski🇵🇱 · K. Dulski · A. Gajos🇵🇱 · B. Glowacz🇵🇱 · M. Gorgol🇵🇱 · B. C. Hiesmayr🇦🇹 and 23 other authors

    The Jagiellonian Positron Emission Tomograph (J-PET) project carried out in the Institute of Physics of the Jagiellonian University is focused on construction and tests of the first prototype of PET scanner for medical diagnostic which allows for the simultaneous 3D imaging of the whole human body using organic scintillators. The J-PET prototype consists of 192 scintillator strips forming three cylindrical layers which are optimized for the detection of photons from the electron-positron annihilation with high time- and high angular-resolutions. In this article we present time calibration and synchronization of the whole J-PET detection system by irradiating each single detection module with a 22Na source and a small detector providing common reference time for synchronization of all the modules.

    ↳ physics.ins-detnucl-exActa Phys.Polon.A(2017)·6 citations
12. 12*

    Helium-Xenon mixtures to improve topological signature in high pressure gas Xenon TPCs

    R. Felkai🇪🇸 · F. Monrabal🇺🇸 · D. Gonzalez-Díaz🇪🇸 · M. Sorel🇪🇸 · N. López-March🇪🇸 · J.J. Gómez-Cadenas🇪🇸 · C. Adams🇺🇸 · V.Álvarez🇪🇸 · L.Arazi🇮🇱 · C.D.R.Azevedo🇵🇹 · J.M.Benlloch-Rodríguez🇪🇸 · F.I.G.M.Borges🇵🇹 and 63 other authors

    Within the framework of xenon-based double beta decay experiments, we propose the possibility to improve the background rejection of an electroluminescent Time Projection Chamber (EL TPC) by reducing the diffusion of the drifting electrons while keeping nearly intact the energy resolution of a pure xenon EL TPC. Based on state-of-the-art microscopic simulations, a substantial addition of helium, around 10 or 15~\%, may reduce drastically the transverse diffusion down to 2.5~mm/$\sqrt{\mathrm{m}}$ from the 10.5~mm/$\sqrt{\mathrm{m}}$ of pure xenon. The longitudinal diffusion remains around 4~mm/$\sqrt{\mathrm{m}}$. Light production studies have been performed as well. They show that the relative variation in energy resolution introduced by such a change does not exceed a few percent, which leaves the energy resolution practically unchanged. The technical caveats of using photomultipliers close to an helium atmosphere are also discussed in detail.

    ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2018)·31 citations
13. 13*

    Analysis procedure of the positronium lifetime spectra for the J-PET detector

    K. Dulski · B. Zgardzinska · P. Bialas · C. Curceanu E. Czerwinski · A. Gajos · B. Głowacz · M. Gorgol · B. C. Hiesmayr · B. Jasinska · D. Kisielewska-Kaminska · G. Korcyl · P. Kowalski and 21 other authors

    Positron Annihilation Lifetime Spectroscopy (PALS) has shown to be a powerful tool to study the nanostructures of porous materials. Positron Emissions Tomography (PET) are devices allowing imaging of metabolic processes e.g. in human bodies. A newly developed device, the J-PET (Jagiellonian PET), will allow PALS in addition to imaging, thus combining both analyses providing new methods for physics and medicine. In this contribution we present a computer program that is compatible with the J-PET software. We compare its performance with the standard program LT 9.0 by using PALS data from hexane measurements at different temperatures. Our program is based on an iterative procedure, and our fits prove that it performs as good as LT 9.0.

    ↳ physics.ins-detnucl-exActa Phys.Polon.A(2017)·5 citations
14. 14*

    Non-trivial effect for the large radius at the dripline of Oxygen isotopes

    N. Itagaki🇯🇵 · A. Tohsaki🇯🇵

    The anomalous large radii are exotic phenomena observed around the neutron dripline. Around the neutron dripline, the weak binding of the last bound neutron(s) causes the drastic increase of the radius, which is called neutron halo structure. Although the nucleus ${}^{24}$O is located at the dripline of Oxygen isotopes, the separation energies of one and two neutron(s) are 4.19 MeV and 6.92 MeV, respectively. In spite of this enough binding, the enhancement of the matter radius is observed. In this study, we microscopically describe the structure change of ${}^{22}$O core in ${}^{24}$O and explain the observed large radius based on the cluster model. Two degrees of freedom for the large radius; the relative distances among four $\alpha$ clusters and size of each $\alpha$ cluster are examined, where Tohsaki interaction, which has finite range three-body terms is employed. The nucleus ${}^{24}$O has the almost the same amount of the clusterization compared with ${}^{22}$O, but the expansion of each $\alpha$ cluster plays an important role. When two neutrons are added to ${}^{22}$O at the center, the expansion of each $\alpha$ clusters is energetically more favored than enhancing the clustering for reducing the kinetic energy of the neutrons. The calculated rms matter radius of ${}^{22}$O and ${}^{24}$O are 2.75 fm and 2.92 fm, respectively. Although these are slightly smaller than the experimental values, the jump at ${}^{24}$O from ${}^{22}$O is reproduced.

    ↳ nucl-thnucl-exPRC(2018)·19 citations
15. 15*

    Comparative study of the inclusive asymmetries induced by polarized protons and antiprotons at 16 GeV/$c$ at the U-70 accelerator

    V.A. Okorokov🇷🇺 · V.V. Abramov🇷🇺 · A.A. Bogdanov🇷🇺 · M.A. Chetvertkov🇺🇸 · V.A. Chetvertkova🇩🇪 · V.V. Mochalov🇷🇺 · S.B. Nurushev🇷🇺 · M.B. Nurusheva🇷🇺 · V.L. Rykov🇷🇺 · P.A. Semenov🇷🇺 · M.N. Strikhanov🇷🇺 · A.N. Vasiliev🇷🇺

    The only comparative study of the inclusive pion single-spin asymmetries produced in the interactions of the polarized protons and antiprotons in collisions with unpolarized proton was carried out at E-704 experiment. Significant asymmetries were found at large $x_F$ and middle $p_T$, ${\pi }^{+}$ and ${\pi }^0$ asymmetries have positive signs while ${\pi }^{-}$ has negative one in the $p^{\uparrow }+p$ collisions, while in the ${\bar{p}}^{\uparrow }+p$ interactions the ${\pi }^{-}$ and ${\pi }^0$ asymmetries have positive signs while ${\pi }^{+}$ has negative sign. Similar experimental study can be done in the SPASCHARM experiment at U-70 accelerator at IHEP for various secondary particles with the use of 16 GeV polarized proton and antiproton beams.

    ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2017)·0 citations
16. 16*

    Resonances in a sudden chemical freeze-out model

    Viktor Begun🇵🇱

    The prediction for $p_T$ spectra of various resonances produced in Pb+Pb collisions at 2.76 TeV at the LHC in equilibrium and non-equilibrium models is made. It includes the $\eta$, $\rho$(770), $\Sigma$(1385), $\Lambda$(1520), and $\Xi$(1530). The apparent differences may allow to distinguish between the models.

    ↳ hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2018)·2 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.