Tue·Dec 3, 2019Tuesday·December 3, 2019

1. 01*

   Clustering in ${}^{18}$O -- absolute determination of branching ratios via high-resolution particle spectroscopy

   S. Pirrie🇬🇧 · C. Wheldon🇬🇧 · Tz. Kokalova🇬🇧 · J. Bishop🇺🇸 · R. Hertenberger🇩🇪 · H.-F. Wirth🇩🇪 · S. Bailey🇬🇧 · N. Curtis🇬🇧 · D. Dell'Aquila🇮🇹 · Th. Faestermann🇩🇪 · D. Mengoni🇮🇹 · R. Smith🇬🇧 · D. Torresi🇮🇹 · A. Turner🇺🇸

   The determination of absolute branching ratios for high-energy states in light nuclei is an important and useful tool for probing the underlying nuclear structure of individual resonances: for example, in establishing the tendency of an excited state towards $\alpha$-cluster structure. Difficulty arises in measuring these branching ratios due to similarities in available decay channels, such as (${}^{18}$O,$\mathbf{n}$) and (${}^{18}$O,$2n$), as well as differences in geometric efficiencies due to population of bound excited levels in daughter nuclei. Methods are presented using Monte Carlo techniques to overcome these issues.

   nucl-exSciPost Phys.Proc.(2020)·2 citations
2. 02*

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

   ALICE Collaboration

   The $p_{\mathrm{T}}$-differential non-linear flow modes, $v_{4,22}$, $v_{5,32}$, $v_{6,33}$ and $v_{6,222}$ for ${\pi }^{\pm }$, ${\mathrm{K}}^{\pm }$ , ${\mathrm{K}}_{\mathrm{S}}^0$ , p + $\overline{\mathrm{p}}$, $\Lambda$ + $\overline{\Lambda }$ and $\varphi$-meson have been measured for the first time at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV in Pb-Pb collisions with the ALICE detector at the Large Hadron Collider. The results were obtained with a multi-particle technique, correlating the identified hadrons with reference charged particles from a different pseudorapidity region. These non-linear observables probe the contribution from the second and third order initial spatial anisotropy coefficients to higher flow harmonics. All the characteristic features observed in previous $p_{\mathrm{T}}$-differential anisotropic flow measurements for various particle species are also present in the non-linear flow modes, i.e. increase of magnitude with increasing centrality percentile, mass ordering at low $p_{\mathrm{T}}$ and particle type grouping in the intermediate $p_{\mathrm{T}}$ range. Hydrodynamical calculations (iEBE-VISHNU) that use different initial conditions and values of shear and bulk viscosity to entropy density ratios are confronted with the data at low transverse momenta. These calculations exhibit a better agreement with the anisotropic flow coefficients than the non-linear flow modes. These observations indicate that non-linear flow modes can provide additional discriminatory power in the study of initial conditions as well as new stringent constraints to hydrodynamical calculations.

   nucl-exhep-exJHEP(2020)·24 citations
3. 03*

   Measurement of Longitudinal Spin Asymmetries for Weak Boson Production at STAR

   Jinlong Zhang (for the STAR Collaboration)🇨🇳

   The production of $W^{\pm }$ bosons in longitudinally polarized proton-proton collisions at RHIC provides a direct probe for the spin-flavor structure of the proton through the parity-violating single-spin asymmetry, $A_L$. At STAR, the leptonic decay channel $W\to e\nu$ can be effectively measured with the electromagnetic calorimeters and time projection chamber. STAR has measured the $A_L(W)$ as a function of the decay electrons pseudorapidity from datasets taken in 2011 and 2012, which has provided significant constraints on the helicity-dependent PDFs of $\bar{u}$ and $\bar{d}$ quarks. In 2013 the STAR experiment collected an integrated luminosity of $\sim$250 pb${}^{-1}$ at $\sqrt{s}=510$ GeV with an average beam polarization of $\sim$56\%, which is more than three times larger than the total integrated luminosity of previous years. The final results from the 2013 dataset for $W$-boson $A_L$ will be reported. Also, the impacts of STAR data on our knowledge of the sea-quark spin-flavor structure of the proton will be discussed.

   ↳ hep-exnucl-exInt.J.Mod.Phys.Conf.Ser.(2016)·0 citations
4. 04*

   HIJING can describe the anisotropy-scaled charge-dependent correlations at the Relativistic Heavy Ion Collider

   Jie Zhao🇺🇸 · Yicheng Feng🇺🇸 · Hanlin Li🇨🇳 · Fuqiang Wang🇺🇸

   The experimentally measured charge-depdendent correlations in heavy ion collisions have been suggested as a signature of the chiral magenetic effect (CME). Early model studies could not reproduce the measurement. For example, the Hijing model yielded far smaller magnitude for the charge-dependent correlation than observed in data. This led to the conclusion that the CME had to be invoked to explain the observed correlations in heavy ion collisions. In this paper we show that this conclusion of the CME interpretation is premature. We show that the reason that Hijing predicts a far smaller correlation than data is because the elliptic anisotrpy ($v_2$) parameter in Hijing is too small. When properly scaled, the Hijing model can reproduce in entirety the measured correlations. We also employ the AMPT model, which has a large enough $v_2$, to demonstrate that the measured data can be easily accommodated by models without invoking the CME.

   ↳ nucl-thnucl-exPRC(2020)·17 citations
5. 05*

   From bound states to the continuum

   Calvin W. Johnson🇺🇸 · Kristina D. Launey🇺🇸 · Naftali Auerbach🇮🇱 · Sonia Bacca🇩🇪 · Bruce R. Barrett🇺🇸 · Carl Brune🇺🇸 · Mark A. Caprio🇺🇸 · Pierre Descouvemont🇧🇪 · W. H. Dickhoff🇺🇸 · Charlotte Elster🇺🇸 · Patrick J. Fasano🇺🇸 · Kevin Fossez🇺🇸 and 26 other authors

   This white paper reports on the discussions of the 2018 Facility for Rare Isotope Beams Theory Alliance (FRIB-TA) topical program "From bound states to the continuum: Connecting bound state calculations with scattering and reaction theory". One of the biggest and most important frontiers in nuclear theory today is to construct better and stronger bridges between bound state calculations and calculations in the continuum, especially scattering and reaction theory, as well as teasing out the influence of the continuum on states near threshold. This is particularly challenging as many-body structure calculations typically use a bound state basis, while reaction calculations more commonly utilize few-body continuum approaches. The many-body bound state and few-body continuum methods use different language and emphasize different properties. To build better foundations for these bridges, we present an overview of several bound state and continuum methods and, where possible, point to current and possible future connections.

   ↳ nucl-thnucl-exJ.Phys.G(2020)·89 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.