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New submissions

[ total of 12 entries: 1-12 ]
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New submissions for Fri, 23 Aug 19

[1]  arXiv:1908.08166 [pdf, other]
Title: Nuclear Isotope Production by Ordinary Muon Capture Reaction
Comments: 21 pages, 5 figures
Subjects: Nuclear Experiment (nucl-ex); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)

Muon capture isotope production (MuCIP) using negative ordinary muon capture reactions (OMC) is used to efficiently produce various kinds of nuclear isotopes for both fundamental and applied science studies. The large capture probability of muon into a nucleus, together with the high intensity muon beam, make it possible to produce nuclear isotopes in the order of 10^{9-10} per second depending on the muon beam intensity. Radioactive isotopes (RIs) produced by MuCIP are complementary to those produced by photon and neutron capture reactions and are used for various science and technology applications. MuCIP on ^{Nat}Mo by using the RCNP MuSIC \muon beam is presented to demonstrate the feasibility of MuCIP. Nuclear isotopes produced by MuCIP are evaluated by using a pre-equilibrium (PEQ) and equilibrium (EQ) proton neutron emission model. Radioactive $^{99}$Mo isotopes and the metastable ^{99m}Tc isotopes, which are used extensively in medical science, are produced by MuCIP on ^{Nat}Mo and ^{100}Mo.

[2]  arXiv:1908.08490 [pdf, other]
Title: Constraining the Sea Quark Distributions Through W$^\pm$ Cross Section Ratio Measurements at STAR
Authors: M. Posik (for the STAR Collaboration)
Comments: Submitted to DIS 2019 Proceedings. 6 pgs. 5 fig
Subjects: Nuclear Experiment (nucl-ex); High Energy Physics - Experiment (hep-ex)

Over the past several years, parton distribution functions (PDFs) have become more precise. However there are still kinematic regions where more data are needed to help constrain global PDF extractions, such as the ratio of the sea quark distributions $\bar{d}$/$\bar{u}$ near the valence region. Furthermore, current measurements appear to suggest different high-$x$ behaviors of this ratio. The $W$ cross section ratio ($W^+$/$W^-$) is sensitive to the unpolarized quark distributions at large $Q^2$ set by the $W$ mass. Such a measurement can be used to help constrain the $\bar{d}$/$\bar{u}$ ratio. The STAR experiment at RHIC is well equipped to measure the leptonic decays of $W$ bosons, in the mid-pseudorapdity range $\left(|\eta| \leq 1 \right)$, produced in proton-proton collisions at $\sqrt{s}$ = 500/510 GeV. At these kinematics STAR is sensitive to quark distributions near $x$ of 0.16. STAR can also measure $W^+$/$W^-$ in a more forward region ranging from 1.0 $< \eta <$1.5, which extends the sea quark sensitivity to higher $x$. RHIC runs from 2011 through 2013 have collected about 350 pb$^{-1}$ of integrated luminosity, and an additional 350 pb$^{-1}$ from the 2017 run. These proceedings will present preliminary results of the 2011-2013 $W^+$/$W^-$ cross section ratio measurements. Additionally, the $W/Z$ cross section ratio, differential and total $W$ and $Z$ cross sections are presented.

Cross-lists for Fri, 23 Aug 19

[3]  arXiv:1908.07605 (cross-list from hep-ph) [pdf, other]
Title: Magnetic fields in heavy ion collisions: flow and charge transport
Subjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

At the earliest times after a heavy-ion collision, the magnetic field created by the spectator nucleons will generate an extremely strong, albeit rapidly decreasing in time, magnetic field. The impact of this magnetic field may have detectable consequences, and is believed to drive anomalous transport effects like the Chiral Magnetic Effect (CME). We detail an exploratory study on the effects of a dynamical magnetic field on the hydrodynamic medium created in the collisions of two ultrarelativistic heavy-ions, using the framework of numerical ideal MagnetoHydroDynamics (MHD) with the ECHO-QGP code. In this study, we consider a magnetic field captured in a conducting medium, where the conductivity can receive contributions from the electromagnetic conductivity $\sigma$ and the chiral magnetic conductivity $\sigma_{\chi}$. We first study the elliptic flow of pions, which we show is relatively unchanged by the introduction of a magnetic field. However, by increasing the magnitude of the magnetic field, we find evidence for an enhancement of the elliptic flow in peripheral collisions. Next, we explore the impact of the chiral magnetic conductivity on electric charges produced at the edges of the fireball. This initial $\sigma_\chi$ can be understood as a long-wavelength effective description of chiral fermion production. We then demonstrate that this chiral charge, when transported by the MHD medium, produces a charge dipole perpendicular to the reaction plane which extends a few units in rapidity. Assuming charge conservation at the freeze-out surface, we show that the produced charge imbalance can have measurable effects on some experimental observables, like $v_1$ or $\langle \sin \phi \rangle$. This demonstrates the ability of a MHD fluid to transport the signature of the initial chiral magnetic fields to late times.

[4]  arXiv:1908.07921 (cross-list from hep-ex) [pdf, other]
Title: Dark Matter at the Intensity Frontier: the new MESA electron accelerator facility
Comments: Proceedings of ALPS 2019, April 22 - 27, 2019, Obergurgl, Austria. arXiv admin note: substantial text overlap with arXiv:1809.07168
Subjects: High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Instrumentation and Detectors (physics.ins-det)

Dark Matter is being searched with a variety of methods, each of which tackles this challenge focusing on different kinds of particles, masses and couplings. Here we describe Dark Matter searches conducted with accelerators and fixed targets. In particular, we highlight the contribution of the experiments being built at the new Mainz Energy-recovery Superconducting Accelerator (MESA) facility. MESA will provide intense electron beams for hadron and nuclear physics, as well as for Dark Matter searches with competitive sensitivities.

[5]  arXiv:1908.08009 (cross-list from physics.ins-det) [pdf]
Title: Network Time Synchronization of the Readout Electronics for a New Radioactive Gas Detection System
Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

In systems with multiple radiation detectors, time synchronization of the data collected from different detectors is essential to reconstruct multi-detector events such as scattering and coincidences. In cases where the number of detectors exceeds the readout channels in a single data acquisition electronics module, multiple modules have to be synchronized, which is traditionally accomplished by distributing clocks and triggers via dedicated connections. To eliminate this added cabling complexity in the case of a new radioactive gas detection system prototype under development at the French Atomic Energy Commission, we implemented time synchronization between multiple XIA Pixie-Net detector readout modules through the existing Ethernet network, based on the IEEE 1588 precision time protocol. The detector system is dedicated to the measurement of radioactive gases at low activity and consists of eight large silicon pixels and two NaI(Tl) detectors, instrumented with a total of three 4-channel Pixie-Net modules. Detecting NaI(Tl)/silicon coincidences will make it possible to identify each radioisotope present in the sample. To allow these identifications at low activities, the Pixie-Net modules must be synchronized to a precision well below the targeted coincidence window of 500-1000 ns. Being equipped with an Ethernet PHY compatible with IEEE 1588 and synchronous Ethernet that outputs a locally generated but system-wide synchronized clock, the Pixie-Net can operate its analog to digital converters and digital processing circuitry with that clock and match time stamps for captured data across the three modules. Depending on the network configuration and synchronization method, the implementation is capable to achieve timing precisions between 300 ns and 200 ps.

[6]  arXiv:1908.08041 (cross-list from physics.ins-det) [pdf, other]
Title: First neutron data recorded at the V20 Test Instrument utilizing prototype chopper systems and beam monitors planned for ESS
Comments: 8 pages, 9 figures
Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

The main objective of the European Spallation Source (ESS) is to perform consistently high impact neutron scattering science using the highest neutron flux of any facility in its class. This ambition is naturally accompanied by operational challenges related to the vertical integration of the instruments' hardware and software shared between collaborators from 13 European countries. The present work will detail integration tests performed at the V20 Test Instrument at Helmholtz-Zentrum Berlin in Germany. An ESS chopper prototype was successfully controlled through the ESS Chopper Integration Controller (CHIC) and Experimental Physics and Industrial Control System (EPICS). Neutron data were successfully collected and time stamped using neutron beam monitors, the ESS prototype detector readout electronics and the Data Management Software Center (DMSC) data acquisition (DAQ) software. Chopper rotation events were timestamped and the chopper disk showed excellent stability and neutron absorption characteristics. The test resulted in (i) the expected time-of-flight (TOF) response, (ii) collected data that compared well with instrument reference data and (iii) revealing the diagnostic power of the performed integration tests. The results of this integration test validate the ESS chopper and detector DAQ architecture choices.

[7]  arXiv:1908.08302 (cross-list from nucl-th) [pdf, other]
Title: First-forbidden transitions in the reactor anomaly
Subjects: Nuclear Theory (nucl-th); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

We describe here microscopic calculations performed on the dominant forbidden transitions in reactor antineutrino spectra above 4 MeV using the nuclear shell model. By taking into account Coulomb corrections in the most complete way, we calculate the shape factor with the highest fidelity and show strong deviations from allowed approximations and previously published results. Despite small differences in the ab initio electron cumulative spectra, large differences on the order of several percents are found in the antineutrino spectra. Based on the behaviour of the numerically calculated shape factors we propose a parametrization of forbidden spectra. Using Monte Carlo techniques we derive an estimated spectral correction and uncertainty due to forbidden transitions. We establish the dominance and importance of forbidden transitions in both the reactor anomaly and spectral shoulder analysis. Based on these results, we conclude that a correct treatment of forbidden transitions is indispensable in both the normalization anomaly and spectral shoulder.

[8]  arXiv:1908.08455 (cross-list from hep-ph) [pdf, other]
Title: Nucleon-antinucleon annihilation at LEAR
Authors: Claude Amsler
Comments: 27 pages, 29 figures, Invited talk at the ECT* workshop on Antiproton-nucleus interactions and related phenomena
Subjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

This report is a historical review of the salient results in low energy antiproton-proton and antineutron-proton annihilation obtained at the Low Energy Antiproton Ring (LEAR), which was operated at CERN between 1983 and 1996. The intention is to provide guidelines for future experiments at the CERN AD/ELENA complex and elsewhere. In the spirit of this workshop, hadron spectroscopy - one of the cornerstones at LEAR - is briefly mentioned, while emphasis is put on the annihilation mechanism on one and two nucleons, the final state multiplicity distributions and the contributions from quarks, in particular in annihilation channels involving strangeness.

Replacements for Fri, 23 Aug 19

[9]  arXiv:1903.05529 (replaced) [pdf, other]
[10]  arXiv:1908.07113 (replaced) [pdf, other]
Title: Neutrino Detectors as Tools for Nuclear Security
Comments: 20 pages, 5 figures, comments welcome, submitted to Rev. Mod. Phys; v2 minor editing correction
Subjects: Physics and Society (physics.soc-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Instrumentation and Detectors (physics.ins-det)
[11]  arXiv:1905.06775 (replaced) [pdf, other]
Title: The onset of $ΛΛ$ hypernuclear binding
Comments: v2 -- 14 pages, 4 figures, 1 table, slightly revised, accepted for publication in PLB
Subjects: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
[12]  arXiv:1907.03647 (replaced) [pdf, other]
Title: Phonon and light read out of a Li$_2$MoO$_4$ crystal with multiplexed kinetic inductance detectors
Comments: 7 pages, 9 figures
Subjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)
[ total of 12 entries: 1-12 ]
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