Tue·Mar 31, 2020Tuesday·March 31, 2020

1. 01*

   Nonfuel Antineutrino Contributions in the High Flux Isotope Reactor

   A.B. Balantekin · H.R. Band · C.D. Bass · D.E. Bergeron · D. Berish · N.S. Bowden · J.P. Brodsky · C.D. Bryan · T. Classen · A.J. Conant · G. Deichert · M.V. Diwan and 44 other authors

   Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties becoming lower than those from theory, carefully considering all sources of ${\overline{\nu }}_e$ is important when making theoretical predictions. One source of ${\overline{\nu }}_e$ that is often neglected arises from the irradiation of the nonfuel materials in reactors. The ${\overline{\nu }}_e$ rates and energies from these sources vary widely based on the reactor type, configuration, and sampling stage during the reactor cycle and have to be carefully considered for each experiment independently. In this article, we present a formalism for selecting the possible ${\overline{\nu }}_e$ sources arising from the neutron captures on reactor and target materials. We apply this formalism to the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the ${\overline{\nu }}_e$ source for the the Precision Reactor Oscillation and Spectrum Measurement (PROSPECT) experiment. Overall, we observe that the nonfuel ${\overline{\nu }}_e$ contributions from HFIR to PROSPECT amount to 1\% above the inverse beta decay threshold with a maximum contribution of 9\% in the 1.8--2.0~MeV range. Nonfuel contributions can be particularly high for research reactors like HFIR because of the choice of structural and reflector material in addition to the intentional irradiation of target material for isotope production. We show that typical commercial pressurized water reactors fueled with low-enriched uranium will have significantly smaller nonfuel ${\overline{\nu }}_e$ contribution.

   nucl-exhep-exPRC(2020)·13 citations
2. 02*

   Shakeup and shakeoff satellite structure in the electron spectrum of ${}^{83}$Kr${}^m$

   R. G. Hamish Robertson🇺🇸 · Vedantha Venkatapathy🇺🇸

   The isotope ${}^{83}$Kr${}^m$, a 1.8-hr isomer of stable ${}^{83}$Kr, has become a standard for the calibration of tritium beta decay experiments to determine neutrino mass. It is also widely used as a low-energy electron source for the calibration of dark-matter experiments. The nominally monoenergetic internal conversion lines are accompanied by shakeup and shakeoff satellites that modify the line shape. We draw on theoretical and experimental information to derive a quantitative description of the satellite spectrum of the K-conversion line.

   nucl-exhep-exPRC(2020)·10 citations
3. 03*

   Search of critical effects in NA61/SHINE

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

   NA61/SHINE is a multi-purpose experiment to study hadron-proton, hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton Synchrotron (SPS). The experiment performs unique measurements for the physics of strong interactions as well as important reference measurements for neutrino and cosmic-ray physics. The primary goals of the experiment are the study of the onset of deconfinement and the search for the critical point of the strongly interacting matter, to uncover the mechanism of thermalisation and to test the validity of statistical models. For this purpose, a two-dimensional scan was performed by varying the beam momentum (13$A$--158$A$~GeV/$c$) and the size of colliding systems (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb). In this contribution, we present recent NA61/SHINE results on the search for critical effects in spectra and fluctuations. We see no clear indication for the onset of deconfinement for intermediate colliding systems. Nevertheless, results from p+p interactions on spectra and onset of deconfinement reveal anomalous behaviour in proximity to transition energy. In fluctuation analysis of collisions of medium size nuclei at the top SPS energy, no prominent signal of critical point was observed.

   nucl-exhep-ex0 citations
4. 04*

   The Q.Q Interaction and Variation of Single Particle Energies

   Mingyang Ma · Praveen C Srivastava🇮🇳 · Larry Zamick🇺🇸

   In this work we make further studies of the quadrupole quadrupole interaction used in shell model calculations.Whereas in a previous work we adjusted the single particle energies so as to obtain the rotatonal spectrum of the Elliott model, we here vary the single particle energies and see the various spectral shapes that evolve.

   ↳ nucl-thnucl-exRom.J.Phys.(2021)·0 citations
5. 05*

   A Novel Experimental Approach for Nanostructure Analysis: Simultaneous Small Angle X-ray and Neutron Scattering (SAXS/SANS)

   Ezzeldin Metwalli🇩🇪 · Klaus Götz🇩🇪 · Sebastian Lages🇩🇪 · Christian Bär🇩🇪 · Tobias Zech🇩🇪 · Dennis M. Noll🇩🇪 · Isabel Schuldes🇩🇪 · Torben Schindler🇩🇪 · Annemarie Prihoda🇩🇪 · Herbert Lang🇩🇪 · Jürgen Grasser🇩🇪 · Mark Jacques🇫🇷 and 5 other authors

   Exploiting small angle X-ray and neutron scattering (SAXS/SANS) on the same sample volume at the same time provides complementary nanoscale structural information at two different contrast situations. Compared with an independent experimental approach, the truly combined SAXS/SANS experimental approach ensures the exactness of the probed samples particularly for in-situ studies. Here, we introduce an advanced portable SAXS system that is dimensionally suitable for installation at D22 zone of ILL. The SAXS apparatus is based on a RIGAKU copper/molybdenum switchable microfocus rotating anode X-ray generator and a DECTRIS detector with a changeable sample-to-detector distance of up to 1.6 m in a vacuum chamber. A science case has been presented to demonstrate the uniqueness of the newly established method at ILL. Temporal structural rearrangements of both, organic stabilizing agents and organically capped gold colloidal particles during gold nanoparticle growth are simultaneously probed, enabling immediate correlated structural information. The newly established nano-analytical method at ILL will open the way for real time investigations of a wide range of innovative nanomaterials and will enable comprehensive in-situ studies on biological systems. A potential development of a fully-automated SAXS/SANS system with a common control environment and additional sample environments, permitting a continual and efficient operation of the system at the hands of ILL users, has also been introduced.

   ↳ physics.ins-detcond-mat.softnucl-ex0 citations
6. 06*

   Gravitational form factors of hyperons in light-cone QCD

   U. Özdem🇹🇷 · K. Azizi🇮🇷

   The quark parts of the gravitational form factors of hyperons are calculated by means of the light-cone QCD sum rule. In the calculations, the distribution amplitudes (DAs) of $\Sigma$, $\Xi$ and $\Lambda$ together with the general forms of their interpolating currents as well as the quark part of the energy-momentum tensor current are used. These form factors can provide information on their mass and distributions of the angular momentum, energy and pressure inside the hyperons. It is obtained that the $Q^2$ dependencies of the hyperon gravitational form factors are nicely characterized by a multipole fit function. Using the fits of these form factors, some mechanical properties such as the mechanical radius of the hyperons and the pressure and energy distributions at the center of these particles are obtained. The obtained results can help us in better understanding of the internal structures of these baryons and the QCD as theory of the strong interaction.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2020)·13 citations
7. 07*

   Lensing Mechanism Meets Small-$x$ Physics: Single Transverse Spin Asymmetry in $p^{\uparrow }+p$ and $p^{\uparrow }+A$ Collisions

   Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸

   We calculate the single transverse spin asymmetry (STSA) in polarized proton-proton ($p^{\uparrow }+p$) and polarized proton-nucleus ($p^{\uparrow }+A$) collisions ($A_N$) generated by a partonic lensing mechanism. The polarized proton is considered in the quark-diquark model while its interaction with the unpolarized target is calculated using the small-$x$/saturation approach, which includes multiple rescatterings and small-$x$ evolution. The phase required for the asymmetry is caused by a final-state gluon exchange between the quark and diquark, as is standard in the lensing mechanism of Brodsky, Hwang and Schmidt. Our calculation combines the lensing mechanism with small-$x$ physics in the saturation framework. The expression we obtain for the asymmetry $A_N$ of the produced quarks has the following properties: (i) The asymmetry is generated by the dominant elastic scattering contribution and $1/N_c^2$ suppressed inelastic contribution (with $N_c$ the number of quark colors); (ii) The asymmetry grows or oscillates with the produced quark's transverse momentum $p_T$ until the momentum reaches the saturation scale $Q_s$, and then only falls off as $1/p_T$ for larger momenta; (iii) The asymmetry decreases with increasing atomic number $A$ of the target for $p_T$ below or near $Q_s$, but is independent of $A$ for $p_T$ significantly above $Q_s$. We discuss how these properties may be qualitatively consistent with the data on $A_N$ published by the PHENIX collaboration and with the preliminary data on $A_N$ reported by the STAR collaboration.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·23 citations
8. 08*

   A Nuclear Periodic Table

   K. Hagino🇯🇵 · Y. Maeno🇯🇵

   There have been many empirical evindences which show that the single-particle picture holds to a good approximation in atomic nuclei. In this picture, protons and neutrons move independently inside a mean-field potential generated by an interaction among the nucleons. This leads to the concept of nuclear shells, similar to the electronic shells in atoms. In particular, the magic numbers due to closures of the nucleonic shells, corresponding to noble gases in elements, have been known to play an important role in nuclear physics. Here we propose a periodic table for atomic nuclei, in which the elements are arranged according to the known nucleonic shells. The nuclear periodic table clearly indicates that nuclei in the vicinity of the magic numbers can be understood in terms of a shell closure with one or two additional nucleons or nucleon holes, while nuclei far from the magic numbers are characterized by nuclear deformation.

   ↳ nucl-thcond-mat.str-elnucl-ex0 citations
9. 09*

   The production of isolated photons in PbPb and pp collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV

   CMS Collaboration

   The transverse energy ($E_{\mathrm{T}}^{\gamma }$) spectra of photons isolated from other particles are measured using proton-proton (pp) and lead-lead (PbPb) collisions at the LHC at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV with integrated luminosities of 27.4 pb${}^{-1}$and 404 $\mu$b${}^{-1}$ for pp and PbPb data, respectively. The results are presented for photons with 25 $<$ $E_{\mathrm{T}}^{\gamma }$ $<$ 200 GeV in the pseudorapidity range $|\eta |$ $<$ 1.44, and for different centrality intervals for PbPb collisions. Photon production in PbPb collisions is consistent with that in pp collisions scaled by the number of binary nucleon-nucleon collisions, demonstrating that photons do not interact with the quark-gluon plasma. Therefore, isolated photons can provide information about the initial energy of the associated parton in photon+jet measurements. The results are compared with predictions from the next-to-leading-order JETPHOX generator for different parton distribution functions (PDFs) and nuclear PDFs (nPDFs). The comparisons can help to constrain the nPDFs global fits.

   ↳ hep-exnucl-exJHEP(2020)·43 citations
10. 10*

    Hadron Blind Cherenkov Counters

    I.Tserruya · K.Aokia · C.Woody

    In this paper, we present some of the most prominent realizations of the HBD concept in real experiments. We describe the first implementation of an HBD that was made in the CERES experiment at CERN using a spectrometer based on a doublet of hadron blind RICH detectors for the measurement of low-mass electron pairs in pA and AA collisions at the SPS. We next present a detailed account of a more extensive realization of the HBD that was made in the PHENIX experiment for the measurement of low-mass electron pairs in central heavy-ion collisions at RHIC, followed by a description of a very similar detector that is currently under construction at J-PARC for the measurement of vector mesons though their $e^{+}{e}^{-}$ decay in pA collisions. We conclude with a brief discussion of possible evolutions of the HBD concept as well as possible developments and uses of HBDs in experiments at the future Electron Ion Collider.

    ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·6 citations
11. 11*

    Statistical hadronization model for heavy-ion collisions in a few GeV energy regime

    Sz. Harabasz🇩🇪 · W. Florkowski🇵🇱 · T. Galatyuk🇩🇪 · M. Gumberidze🇩🇪 · R. Ryblewski🇵🇱 · P. Salabura🇵🇱 · J. Stroth🇩🇪

    We show that the transverse-mass and rapidity spectra of protons and pions produced in Au-Au collisions at sqrt(sNN) = 2.4 GeV can be well reproduced in a thermodynamic model assuming single freeze-out of particles from a spherically symmetric hypersurface. This scenario corresponds to a physical picture used by Siemens and Rasmussen in the original formulation of the blast-wave model. Our framework modifies and extends this approach by incorporation of a Hubble-like expansion of QCD matter and inclusion of resonance decays. In particular, the Delta(1232) resonance is taken into account, with a width obtained from the virial expansion. Altogether, our results bring evidence for substantial thermalization of the matter produced in heavy-ion collisions in a few GeV energy regime and its nearly spherical expansion.

    ↳ nucl-thnucl-exPRC(2020)·30 citations
12. 12*

    Differential Cross Sections for Neutron-Proton Scattering in the Region of the $d^{\ast }(2380)$ Dibaryon Resonance

    P. Adlarson · W. Augustyniak · W. Bardan · M. Bashkanov · F.S. Bergmann · M. Berłowski · H. Bhatt · M. Büscher · H. Calén · I. Ciepał · H. Clement · D.Coderre and 93 other authors

    Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized $\vec{n}p$ scattering performed in the energy region of the $d^{\ast }(2380)$ dibaryon resonance covering the the range of beam energies $T_n$ = 0.98 - 1.29 GeV ($\sqrt{s}$ = 2.32 - 2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process $dp\to np+p_{spectator}$. That way the $np$ differential cross section $\sigma (\Theta )$ was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power $A_y(\Theta )$ measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled ${}^3{D}_3{-}^3{G}_3$ waves.

    ↳ hep-exnucl-exPRC(2020)·9 citations
13. 13*

    An electron linac with high beam intensity over 1-Ampere for disposal of radioactive waste

    Y. Kawashima🇯🇵 · T. Asaka🇯🇵 · H. Ego🇯🇵 · M. Hara🇯🇵

    In order to dissipate long-lived radioactive waste, not only high ux proton accelerator but also electron linac have been proposed. A proton accelerator directly induces nuclear fission and mutation. On the other hand, electron beam has two processes: production of gamma rays through bremsstrahlung and produced gamma rays are available for the (gamma ; n) reaction. Protons dissipate nuclei and simultaneously newly produce radioisotopes of by-products. Since an electron linac produces less radioactive wastes, we focus only an electron linac with high beam intensity more than 1-Ampere. To reduce the yield of by-products for radioisotopes as less as possible, we accelerate electron beam with the energy less than 30 MeV. The accelerated beam intensity is designed to be more than 1-Ampere. To realize an electron linac with high intensity, the operation for the linac is not pulsed one, but continuous wave. To accelerate electron beam, we install higher-order-modes (HOMs) free normal conducting cavities to suppress beam instabilities.

    ↳ physics.acc-phnucl-ex0 citations
14. 14*

    Rapidity decorrelation of anisotropic flow caused by hydrodynamic fluctuations

    Azumi Sakai🇯🇵 · Koichi Murase🇯🇵 · Tetsufumi Hirano🇯🇵

    We investigate the effect of hydrodynamic fluctuations on the rapidity decorrelations of anisotropic flow in high-energy nuclear collisions using a (3+1)-dimensional integrated dynamical model. The integrated dynamical model consists of twisted initial conditions, fluctuating hydrodynamics, and hadronic cascades on an event-by-event basis. To understand the rapidity decorrelation, we analyze the factorization ratio in the longitudinal direction. Comparing the factorization ratios between fluctuating hydrodynamics and ordinary viscous hydrodynamics, we find a sizable effect of hydrodynamic fluctuations on rapidity decorrelations. We also propose to calculate the Legendre coefficients of the flow magnitude and the event-plane angle to understand the decorrelation of anisotropic flow in the longitudinal direction.

    ↳ nucl-thhep-phnucl-exPRC(2020)·40 citations
15. 15*

    Antineutrino Detectors Remain Impractical for Nuclear Explosion Monitoring

    Michael Foxe🇺🇸 · Theodore Bowyer🇺🇸 · Rachel Carr · John Orrell🇺🇸 · Brent VanDevender🇺🇸

    Fission explosions produce large numbers of antineutrinos. It is occasionally asked whether this distinctive, unshieldable emission could help reveal clandestine nuclear weapon explosions. The practical challenge encountered is that detectors large enough for this application are cost prohibitive, likely on the multi-billion-dollar scale. In this paper, we review several hypothetical use cases for antineutrino detectors as supplements to the seismic, infrasound, hydroacoustic, and airborne radionuclide sensors of the Comprehensive Nuclear-Test-Ban Treaty Organization's International Monitoring System. In each case, if an anti-neutrino detector could be constructed that would compete with existing capabilities, we conclude that the cost would considerably outstrip the value it might add to the existing monitoring network, compared to the significantly lower costs for the same or superior capability.

    ↳ physics.soc-phhep-exnucl-exphysics.ins-det2 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.