Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session KB: Nuclear reactions: Hadrons/Light Ions |
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Chair: Belen Montegudo Godoy, MSU-NSCL/FRIB |
(Author Not Attending)
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KB.00001: Comparison of ToF vs Unfolding Methods for Neutron Spectroscopy Studies of with CATRiNA Jesus Perello, Ashton Morelock, Sergio Almaraz-Calderon, Lagy Baby, Kenneth Hanselman, Nathan Gerken The (d,n) reaction, the analog to the (d,p) reaction, is an important spectroscopic tool, yet hardly any measurements involve the detection of an outgoing neutron due to the difficulty of extracting neutron energy. The standard method for measuring neutron energies is time-of-flight (ToF) where the arrival time of neutrons are measured in reference to gamma-rays. Recently, deuterated liquid scintillators have gained great interest in nuclear physics research due to their pulse-shape discrimination capabilities, and a distinct peak in their pulse-height (PH) spectrum that can be directly related to the incident neutron energy. At FSU, we have built a response matrix for the CATRiNA deuterated neutron detector array as well as an unfolding algorithm to obtain neutron energies from their PH spectra. In this work we present results from a direct comparison of spectroscopic information obtained using CATRiNA by ToF and PH unfolding methods . Both, ToF and PH spectra unfolding, techniques have been used to obtain differential cross-sections and spectroscopic factors for states populated in the $^{12}$C(d,n)$^{13}$N and d(d,n)$^3$He reactions at beam energies of E$_{lab}$= 4-8 MeV. [Preview Abstract] |
Saturday, October 31, 2020 8:42AM - 8:54AM |
KB.00002: Analysis of Hadronization in QGP on nuclear collisions Suresh Ahuja The Standard Model(SM) of particle physics describes LHC pp collisions concerning large momentum transfer scales. But at lower scales the perturbative approach breaks down, requiring development of phenomenological models. There are limitations in SM such as the scale of Higgs Boson mass is being much different from naive quantum-mechanical expectations, Dark matter (DM) remains an enigma, despite extensive astronomical confirmation of its existence, \underline {Neutrino masses} are observed to be nonzero~and elements of the Pontecorvo--Maki--Nakagawa--Sakata matrix have been measured, but these masses are not easily accounted for in the Standard Model. Numerical lattice simulations of Quantum Chromodynamics (QCD) predict the formation of a deconfined Quark-Gluon Plasma (QGP) at a transition temperature. . In a coalescence plus fragmentation approach the heavy baryon/meson ratio is a significant parameter with higher transverse momentum. A coalescence model considering aggregation of charm quarks and stability of top quarks is analyzed which considers inelastic deformation, collision energy (binding energy, and formation of loose particles on reaching plateau in clusters on Hadronization. Replace this text with your abstract body. [Preview Abstract] |
Saturday, October 31, 2020 8:54AM - 9:06AM |
KB.00003: Status of the Atlas of Neutron Resonances David Brown, Gustavo Nobre, Grier Sayers, Sophia Hollick, Pedro Rodriguez The \textit{Atlas of Neutron Resonances} is the most comprehensive compilation of neutron resonances, thermal cross sections, resonance integrals and Maxwellian averaged cross sections generally available. For decades, the \textit{Atlas} was carefully curated and maintained by Dr. Said Mughabghab who sadly passed on during the summer of 2018 after publishing the 2018 edition of the \textit{Atlas}. We are continuing the development of this important compendium. To a large extent, the \textit{Atlas} book is generated from a series of text files given in a single purpose domain-specific format. Therefore we developed a software API and began the systematic assessment of the \textit{Atlas} files. With this work past, we are now focusing on new efforts to expand the quality and scope of the \textit{Atlas}. Current and recently completed projects include a cross comparison of the \textit{Atlas} bibliography with Nuclear Science References and the EXFOR data library, a better determination of average resonance parameters, and using machine learning to assess the correctness of the spin group assignments of resonances tabulated in the \textit{Atlas}. [Preview Abstract] |
Saturday, October 31, 2020 9:06AM - 9:18AM |
KB.00004: Measurements of generalized jet angularities in pp collisions at $\sqrt{s} = 5.02$ TeV with ALICE Ezra Lesser In recent years jet substructure observables have been used at the LHC as instruments to search for new physics as well as to test perturbative and probe non-perturbative processes in QCD. One such observable, the generalized jet angularity, is of particular interest due its infrared and collinear (IRC) safety and thus calculability from first principles. Its general form has two continuous parameters $\beta$ and $\kappa$, which weight the relative jet constituent angle and $p_\text{T}$, espectively. These can be varied along with the jet radius $R$ to recast the observable while maintaining IRC safety, therefore providing various configurations to systematically constrain theoretical calculations. The high-precision capability of the ALICE tracking system allows a unique opportunity at LHC energies to measure tracks with low $p_\text{T}$, permitting both accessibility to the softer components inside jets as well as measurement of jets with altogether lower $p_\text{T}$. We report the generalized jet angularities in ALICE using pp collisions at $\sqrt{s}$ = 5.02 TeV with charged particle tracks. The parameters $\kappa$ = 1 and $\beta$ = 1, 1.5, 2, 3 are investigated at both large and small values of $R$. Results are presented and compared to theoretical models. [Preview Abstract] |
Saturday, October 31, 2020 9:18AM - 9:30AM |
KB.00005: Transverse Single-Spin Asymmetry for Electromagnetic Jets at Forward Rapidities at STAR in p$^\uparrow$ + p Collisions at $\sqrt s$ = 200 GeV Latiful Kabir There have been various attempts, both experimentally and theoretically, to understand the origin of the unexpectedly large transverse single-spin asymmetries ($A_N$) for inclusive hadron production at forward rapidity in p$^\uparrow$ + p collisions that persist at high center-of-mass energies. Two proposed potential sources are the twist-3 contributions in the collinear factorization and the transverse-momentum-dependent contributions from either the initial-state quark and gluon Sivers functions or the final-state Collins fragmentation function. In 2015 and 2017, RHIC collected data from transversely polarized pp collisions, which are ideal to further characterize $A_N$ and explore its potential sources. The STAR Forward Meson Spectrometer (FMS) and Endcap Electromagnetic Calorimeter (EEMC), having pseudo-rapidity ($\eta$) coverages of 2.6 - 4.2 and 1.1 - 2.0 respectively, can be used to detect photons, neutral pions, and eta mesons. We present an analysis update for $A_N$ of electromagnetic jets in FMS and EEMC using p$^\uparrow$ + p collisions at $\sqrt s = $ 200 GeV. In this analysis, we explore the dependences of $A_N$ on photon multiplicity inside the jet, jet transverse momentum, and jet energy. [Preview Abstract] |
Saturday, October 31, 2020 9:30AM - 9:42AM |
KB.00006: MCNP Simulation Study of the Dual Radiation Rotating Scattering Mask for Localization of Gamma and Neutron Sources Devon Loomis, Ivan Novikov, Alex Barzilov Recent advancements in the development of scintillation materials capable of the simultaneous detection of gamma rays and neutrons have made it possible to significantly simplify radiation detection systems, where a single detector replaces a high pressured He-3 tube and a scintillation crystal. Capitalizing on these recent advances, a novel radiation detecting system was developed to detect and localize gamma and neutron radiation sources using a specially designed Dual Radiation Rotating Scattering Mask (DRRSM). The DRRSM synthesizes concepts employed in rotational modulation collimators and coded-aperture imaging systems in order to simultaneously localize and discriminate neutron and gamma sources with various energies. The DRRSM consists of small voxels of lead to attenuate gamma rays and UHMW poly to attenuate and scatter neutrons. It rotates around the detector axis, modulating the detector's signal in a way that is unique to the source location. A Maximum Likelihood Estimation Maximization algorithm is then used to convert the modulated signal to its corresponding source location. We describe the experimental system design and analyze the results from the MCNP transport code simulations that have been used to validate the system performance. [Preview Abstract] |
Saturday, October 31, 2020 9:42AM - 9:54AM |
KB.00007: New chromium reaction evaluations Gustavo Nobre, Marco Pigni, David Brown, Roberto Capote, Andrej Trkov, Ramon Arcilla, Arantzazu Cuadra Chromium is very common in many nuclear applications as one of the main components in structural materials, secondary only to iron in stainless steel alloys. Re-evaluation of iron isotopes through the CIELO project, released in the ENDF/B-VIII.0 library, revealed that poor performance of steel in simulations of zero-power nuclear reactors is due to uncertainties in the previous chromium evaluations. Even though minor Cr isotopes constitute less than 17\% of $^{\mathrm{Nat}}$Cr, there are strong capture resonances in the low neutron-incident energy region driven by $^{50,53}$Cr cross sections. Therefore, we present new evaluations for all stable Cr isotopes, using modern nuclear theory and the EMPIRE code framework, and new evaluations of resonance data. Monte Carlo simulations for critical assemblies using new evaluations show significant improvement in the agreement with observed values. Evaluation of fast-neutron range incorporates many inelastic data experiments for the first time, in a consistent manner between neutron and gamma cross sections. [Preview Abstract] |
Saturday, October 31, 2020 9:54AM - 10:06AM |
KB.00008: Improving the probability tables of the cross section of near closed-shell nuclei Matteo Vorabbi, Dave Brown, Caleb Mattoon, Gert Godfree, Bret Beck The level density distribution of near closed-shell nuclei is much lower than the typical nucleus, therefore, the cross sections show significant fluctuations and these fluctuations are not predictable. The current methodology used to describe such behavior and construct the probability table of the cross section is based on the extrapolation of the average resonance widths and average resonance spacings from the resonance region and use these parameters to construct the probability table. Although this is a standard and widely used technique, it does not take into account the existing experimental data, such for total and the elastic cross section. Our goal is to extend the current theory and provide a more general approach to compute the probability distribution function of the cross section combining the existing probability tables and the available experimental data. Results will be presented for $^{\mathrm{90}}$Zr. [Preview Abstract] |
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