Tue·Nov 5, 2019Tuesday·November 5, 2019

1. 01*

   Methods for a blind analysis of isobar data collected by the STAR collaboration

   STAR Collaboration: J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · A. Aparin · E. C. Aschenauer · M. U. Ashraf and 344 other authors

   In 2018, the STAR collaboration collected data from ${}_{44}^{96}Ru{+}_{44}^{96}Ru$ and ${}_{40}^{96}Zr{+}_{40}^{96}Zr$ at $\sqrt{s_{NN}}=200$ GeV to search for the presence of the chiral magnetic effect in collisions of nuclei. The isobar collision species alternated frequently between ${}_{44}^{96}Ru{+}_{44}^{96}Ru$ and ${}_{40}^{96}Zr{+}_{40}^{96}Zr$. In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data, STAR developed a three-step blind analysis procedure. Analysts are initially provided a "reference sample" of data, comprised of a mix of events from the two species, the order of which respects time-dependent changes in run conditions. After tuning analysis codes and performing time-dependent quality assurance on the reference sample, analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual $\approx 30$-minute data-taking runs. For this sample, species-specific information is disguised, but individual output files contain data from a single isobar species. Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage. Following these modifications, the "frozen" code is passed over the fully un-blind data, completing the blind analysis. As a check of the feasibility of the blind analysis procedure, analysts completed a "mock data challenge," analyzing data from $Au+Au$ collisions at $\sqrt{s_{NN}}=27$ GeV, collected in 2018. The $Au+Au$ data were prepared in the same manner intended for the isobar blind data. The details of the blind analysis procedure and results from the mock data challenge are presented.

   nucl-exhep-exNucl.Sci.Tech.(2021)·51 citations
2. 02*

   Single-Particle Structure of Neutron-Rich Sr Isotopes Via d( 94,95,96 Sr, p) Reactions

   S. Cruz🇨🇦 · K. Wimmer🇯🇵 · P.C. Bender🇨🇦 · R. Krücken🇨🇦 · G. Hackman🇨🇦 · F. Ames🇨🇦 · C. Andreoiu🇨🇦 · R.A.E. Austin🇨🇦 · C.S. Bancroft🇺🇸 · R. Braid🇺🇸 · T. Bruhn🇨🇦 · W.N. Catford🇬🇧 and 23 other authors

   The region around neutron number N = 60 in the neutron-rich Sr and Zr nuclei is one of the most dramatic examples of a ground state shape transition from (near) spherical below N = 60 to strongly deformed shapes in the heavier isotopes. The single-particle structure of 95-97Sr approaching the ground state shape transition at 98 Sr has been investigated via single-neutron transfer reactions using the (d, p) reaction in inverse kinematics. These reactions selectively populate states with a large overlap of the projectile ground state coupled to a neutron in a single-particle orbital. Radioactive 94,95,96Sr nuclei with energies of 5.5 AMeV were used to bombard a CD 2 target. Recoiling light charged particles and {\gamma} rays were detected using a quasi-4{\pi} silicon strip detector array and a 12 element Ge array. The excitation energy of states populated was reconstructed employing the missing mass method combined with {\gamma}-ray tagging and differential cross sections for final states were extracted. A reaction model analysis of the angular distributions allowed for firm spin assignments to be made for the low-lying 352, 556 and 681 keV excited states in 95Sr and a constraint has been placed on the spin of the higher-lying 1666 keV state. Angular distributions have been extracted for 10 states populated in the d(95Sr,p)96Sr reaction, and constraints have been provided for the spins and parities of several final states. Results are compared to shell model calculations in several model spaces and the structure of low-lying states in 94Sr and 95Sr is well-described. The spectroscopic strength of the 0+ and 2 states in 96Sr is significantly more fragmented than predicted.

   nucl-exPRC(2019)·11 citations
3. 03*

   Recent results from NA61/SHINE

   Szymon Pulawski

   The research programme of the NA61 collaboration covers a wide range of hadronic physics in the CERN SPS energy range, encompassesing measurements of hadron-hadron, hadron-nucleus as well as nucleus-nucleus collisions. The latter are analysed to better understand the properties of hot and dense nuclear matter. In this paper recent results of particle production properties as well event by event fluctuations in proton-proton, Be+Be and Ar+Sc interactions at beam energies of 19A/20A, 30A, 40A, 75A/80A and 158A GeV/c are presented.

   nucl-exhep-exActa Phys.Polon.B(2019)·2 citations
4. 04*

   Experimental Aspects of Jet Physics at a Future EIC

   B. S. Page🇺🇸 · Xiaoxuan Chu🇺🇸 · E. C. Aschenauer🇺🇸

   In this work, we present an overview of experimental considerations relevant to the utilization of jets at a future Electron-Ion Collider (EIC), a subject which has been largely overlooked up to this point. A comparison of jet-finding algorithms and resolution parameters is presented along with a detailed analysis of basic jet quantities, such as multiplicities and kinematic distributions. A characterization of the energy in the event not associated with a jet is also made. In addition, detector requirements and the effects of realistic detector resolutions are discussed. Finally, an example analysis is presented in which dijets are used to access the gluon helicity contribution to the spin of the proton.

   ↳ hep-phhep-exnucl-exPRD(2020)·38 citations
5. 05*

   Measurement of ambient neutrons in an underground laboratory at Kamioka Observatory and future plan

   Keita Mizukoshi · Ryosuke Taishaku · Keishi Hosokawa · Kazuyoshi Kobayashi · Kentaro Miuchi · Tatsuhiro Naka · Atsushi Takeda · Masashi Tanaka · Yoshiki Wada · Kohei Yorita

   Ambient neutrons are one of the most serious backgrounds for underground experiments in search of rare events. The ambient neutron flux in an underground laboratory of Kamioka Observatory was measured using a ${}^3\mathrm{He}$ proportional counter with various moderator setups. Since the detector response largely depends on the spectral shape, the energy spectra of the neutrons transported from the rock to the laboratory were estimated by Monte-Carlo simulations. The ratio of the thermal neutron flux to the total neutron flux was found to depend on the thermalizing efficiency of the rock. Thus, the ratio of the count rate without a moderator to that with a moderator was used to determine this parameter. Consequently, the most-likely neutron spectrum predicted by the simulations for the parameters determined by the experimental results was obtained. The result suggests an interesting spectral shape, which has not been indicated in previous studies. The total ambient neutron flux is $(23.5\pm 0.7{{}_{stat.}}_{-2.1}^{+1.9}{}_{sys.})\times 10^{-6}$ cm${}^{-2}$ s${}^{-1}$. In this paper, we explain our method of the result and discuss our future plan.

   ↳ physics.ins-dethep-exnucl-exJ.Phys.Conf.Ser.(2020)·0 citations
6. 06*

   Fabrication and beam test of a silicon-tungsten electromagnetic calorimeter

   Sanjib Muhuri🇮🇳 · Sourav Mukhopadhyay🇮🇳 · Vinay B. Chandratre🇮🇳 · Tapan K. Nayak🇮🇳 · Sumit Kumar Saha🇮🇳 · Sanchari Thakur🇮🇳 · Rama N. Singaraju🇮🇳 · Jogender Saini🇮🇳 · Anthony van den Brink🇳🇱 · Tatsuya Chujo🇯🇵 · Rajendra Nath Patra🇮🇳 · Marco van Leeuwen🇳🇱 and 4 other authors

   A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1~cm${}^2$) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from $-300$~fC to $+500$~fC. Another ASIC with a larger dynamic range, $\pm 600$~fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy ($E$) with that of the incident particle energy ($E_0$) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on $E_0$ has been found to be $\sigma /E=(15.36/\sqrt{E_0(\mathrm{GeV})}\oplus 2.0)\%$.

   ↳ physics.ins-dethep-exnucl-exJINST(2020)·14 citations
7. 07*

   Coherent Elastic Neutrino-Nucleus Scattering at the European Spallation Source

   D. Baxter🇺🇸 · J.I. Collar🇺🇸 · P. Coloma🇪🇸 · C.E. Dahl🇺🇸 · I. Esteban🇪🇸 · P. Ferrario🇪🇸 · J.J. Gomez-Cadenas🇪🇸 · M. C. Gonzalez-Garcia🇪🇸 · A.R.L. Kavner🇺🇸 · C.M. Lewis🇺🇸 · F. Monrabal🇪🇸 · J. Muñoz Vidal🇪🇸 and 3 other authors

   The European Spallation Source (ESS), presently well on its way to completion, will soon provide the most intense neutron beams for multi-disciplinary science. Fortuitously, it will also generate the largest pulsed neutrino flux suitable for the detection of Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS), a process recently measured for the first time at ORNL's Spallation Neutron Source. We describe innovative detector technologies maximally able to profit from the order-of-magnitude increase in neutrino flux provided by the ESS, along with their sensitivity to a rich particle physics phenomenology accessible through high-statistics, precision CE$\nu$NS measurements.

   ↳ physics.ins-dethep-exhep-phnucl-exJHEP(2020)·127 citations
8. 08*

   Probing the partonic degrees of freedom in high multiplicity p-Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV

   Wenbin Zhao🇨🇳 · Che Ming Ko🇺🇸 · Yu-Xin Liu🇨🇳 · Guang-You Qin🇨🇳 · Huichao Song🇨🇳

   We investigate the role of partonic degrees of freedom in high multiplicity p-Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV carried out at the Large Hadron Collider (LHC) by studying the production and collective flow of identified hadrons at intermediate $p_T$ via the coalescence of soft and hard partons generated from viscous hydrodynamics (VISH2+1) and the energy loss model (LBT), respectively. We find that combining the intermediate $p_T$ hadrons from the coalescence with the low $p_T$ hadrons from hydrodynamics and high $p_T$ hadrons from the jet fragmentation, our Hydro-Coal-Frag model provides a nice description of the measured $p_T$-spectra and the differential elliptic flow $v_2(p_T)$ of pions, kaons and protons over the $p_T$ range from 0 to 6 GeV. We further demonstrate the necessity of including the quark coalescence contribution to reproduce the experimentally observed approximate number of constituent quark scaling of hadron $v_2$ at intermediate $p_T$. Our results thus indicate the importance of partonic degrees of freedom and also hint at the possible formation of quark-gluon plasma in high multiplicity p+Pb collisions at the LHC.

   ↳ nucl-thhep-phnucl-exPRL(2020)·100 citations
9. 09*

   Charge asymmetry dependence of flow and a novel correlator to detect the chiral magnetic wave in a multiphase transport model

   Diyu Shen🇨🇳 · Jinhui Chen🇨🇳 · Guoliang Ma🇨🇳 · Yu-Gang Ma🇨🇳 · Qiye Shou🇨🇳 · Song Zhang🇨🇳 · Chen Zhong🇨🇳

   In a multiphase transport model with the initial electric quadrupole moment, we studied and discussed the charge asymmetry ($A_{\mathrm{ch}}$) dependence of flow at varied kinematic windows in semi-central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. We then proposed a novel correlator $W$ which specially focuses on the difference of elliptic flow between positively and negatively charged hadrons induced by the chiral magnetic wave and, more importantly, is irrelevant to the ambiguous $A_{\mathrm{ch}}$. We found that the distribution of the second order correlator $W_2$ displays a convex structure in the absence of the quadrupole and a concave shape in the presence of the quadrupole. We also studied the response of $W_n$ for both signal and resonance background in a toy model and in analytical calculation. Such a method provides a new way to detect the chiral magnetic wave.

   ↳ hep-phnucl-exPRC(2019)·10 citations
10. 10*

    Spectrum of fully-heavy tetraquarks from a diquark+antidiquark perspective

    M. A. Bedolla🇲🇽 · J. Ferretti🇺🇸 · C. D. Roberts🇨🇳 · E. Santopinto🇮🇹

    Using a relativized diquark model Hamiltonian, we calculate the masses of $J^{PC}=0^{++}$ ground-state tetraquarks in the following systems: $bs\bar{b}\bar{s}$, $bb\bar{n}\bar{n}$ ($n=u,d$), $bb\bar{s}\bar{s}$, $cc\bar{c}\bar{c}$, $bb\bar{b}\bar{b}$, $bc\bar{b}\bar{c}$ and $bb\bar{c}\bar{c}$. We also compute extensive spectra for the fully-heavy quark flavour combinations. Finally, as a test of the diquark model approach, we compute the masses of fully-heavy baryons in the diquark model. Our results may be compared soon to the forthcoming experimental data for fully-heavy three-quark systems.

    ↳ hep-phhep-exhep-latnucl-ex+1EPJC(2020)·190 citations
11. 11*

    Nucleon/Hyperon Physics at BES

    Stephen Lars Olsen🇨🇳

    The year 2019 marks the 30th anniversary of BES and the 100th anniversary of Rutherford's discovery of the proton. In spite of the fact that when BES operations started the proton was already 70 years old and the strange hyperons were all over 25, BES continues to make important and unique measurements of nucleon and hyperon properties, including some interesting discoveries.

    ↳ hep-exhep-phnucl-ex1 citation
12. 12*

    Absorption of $\omega$ and $\varphi$ mesons in the inclusive photonuclear reaction

    Swapan Das🇮🇳

    The $\omega$ and $\varphi$ mesons dominantly decay outside the nucleus because the decay-lengths of them are much larger than the dimension of the nucleus. Therefore, the medium modification of the above mesons is studied through their absorption in the nucleus. CLAS collaboration at Jefferson Laboratory (Jlab) has investigated the absorption of the $\omega$ and $\varphi$ mesons by measuring the nuclear transparency ratios for them in the $\gamma A\to \omega (\varphi )X\to e^{+}{e}^{-}X$ reaction. The nuclear transparency ratios for both $\omega$ and $\varphi$ mesons in the above reactions have been calculated, and those are compared with the experimental findings, reported from Jlab, to estimate the $\omega$ meson nucleon and $\varphi$ meson nucleon cross sections in the nucleus.

    ↳ nucl-thnucl-exEPJA(2019)·6 citations
13. 13*

    Quark number scaling of $p_T$ spectra for $\Omega$ and $\varphi$ in relativistic heavy-ion collisions

    Jun Song🇨🇳 · Feng-lan Shao🇨🇳 · Zuo-tang Liang🇨🇳

    We show that the experimental data of transverse momentum ($p_T$) spectra of $\Omega$ baryon and $\varphi$ meson at mid-rapidity in heavy-ion collisions exhibit the constituent quark number scaling in a wide energy range from RHIC to LHC. Such a scaling behavior is a direct consequence of quark combination mechanism via equal velocity combination and provides a very convenient way to extract the $p_T$ spectrum of strange quarks at hadronization. We present the results of strange quarks obtained from the available data and study the properties in particular the energy dependence of the averaged transverse momentum $⟨p_T⟩$ and the transverse radial flow velocity $⟨\beta ⟩$ with a hydrodynamics-motivated blast-wave model.

    ↳ nucl-thnucl-exPRC(2020)·16 citations
14. 14*

    Unrecognized Sources of Uncertainties (USU) in Experimental Nuclear Data

    R. Capote🇦🇹 · S. Badikov · A. Carlson🇺🇸 · I. Duran🇪🇸 · F. Gunsing🇫🇷 · D. Neudecker🇺🇸 · V.G. Pronyaev🇦🇹 · P. Schillebeeckx🇧🇪 · G. Schnabel🇸🇪 · D.L. Smith🇺🇸 · A. Wallner🇦🇺

    Evaluated nuclear data uncertainties are often perceived as unrealistic, most often because they are thought to be too small. The impact of this issue in applied nuclear science has been discussed widely in recent years. Commonly suggested causes are: poor estimates of specific error components, neglect of uncertainty correlations, and overlooked known error sources. However, instances have been reported where very careful, objective assessments of all known error sources have been made with realistic error magnitudes and correlations provided, yet the resulting evaluated uncertainties still appear to be inconsistent with observed scatter of predicted mean values. These discrepancies might be attributed to significant unrecognized sources of uncertainty (USU) that limit the accuracy to which these physical quantities can be determined. The objective of our work has been to develop procedures for revealing and including USU estimates in nuclear data evaluations involving experimental input data. We conclude that the presence of USU may be revealed, and estimates of magnitudes made, through quantitative analyses. This paper identifies several specific clues that can be explored by evaluators in identifying the existence of USU. It then describes numerical procedures to generate quantitative estimates of USU magnitudes. Key requirements for these procedures to be viable are that sufficient numbers of data points be available, for statistical reasons, and that additional supporting information about the measurements be provided by the experimenters. Realistic examples are described to illustrate these procedures and demonstrate their outcomes as well as limitations. Our work strongly supports the view that USU is an important issue in nuclear data evaluation, with significant consequences for applications, and that this topic warrants further investigation by the nuclear science community.

    ↳ physics.data-annucl-exnucl-thNucl.Data Sheets(2020)·22 citations
15. 15*

    Development of radioactive beams at ALTO: Part 2. Influence of the UCx target microstructure on the release properties of fission products

    Julien Guillot🇫🇷 · Brigitte Roussière🇫🇷 · Sandrine Tusseau-Nenez🇫🇷 · Denis S. Grebenkov🇫🇷 · Nicole Barré-Boscher🇫🇷 · Elie Borg🇫🇷 · Julien Martin🇫🇷

    Producing intense radioactive beams, in particular those consisting of short-lived isotopes requires the control of the release efficiency. The released fractions of 11 elements were measured on 14 samples that were characterized by various physicochemical analyses in a correlated paper (Part 1). A multivariate statistical approach, using the principal component analysis, was performed to highlight the impact of the microstructure on the release properties. Samples that best release fission products consist of grains and aggregates with small size and display a high porosity distributed on small diameter pores. They were obtained applying a mixing of ground uranium dioxide and carbon nanotubes powders leading to homogeneous uranium carbide samples with a porous nanostructure. A modelling under on-line ALTO conditions was carried out using the FLUKA code to compare the yields released by an optimized and a conventional target.

    ↳ physics.ins-detnucl-exphysics.app-phNucl.Instrum.Meth.B(2019)·4 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.