Tue·Dec 22, 2020Tuesday·December 22, 2020

1. 01*

   Extraction of the specific shear viscosity of quark-gluon plasma from two-particle transverse momentum correlations

   Victor Gonzalez🇺🇸 · Sumit Basu🇸🇪 · Pedro Ladron de Guevara🇪🇸 · Ana Marin🇩🇪 · Jinjin Pan🇺🇸 · Claude A. Pruneau🇺🇸

   The specific shear viscosity, $\eta /s$, of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions at RHIC and LHC is estimated based on the progressive longitudinal broadening of transverse momentum two-particle correlators, $G_2$, reported as a function of collision centrality by the STAR and ALICE experiments. Estimates are computed as a function of collision centrality using the Gavin ansatz which relates the $G_2$ longitudinal broadening to the specific shear viscosity. Freeze out times required for the use of the ansatz are computed using a linear fit of freeze out times reported as a function of the cubic root of the charged particle pseudorapidity density $(\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta {)}^{1/3}$. Estimates of $\eta /s$ based on ALICE data exhibit little to no dependence on collision centrality at LHC energy, while estimates obtained from STAR data hint that $\eta /s$ might be a function of collision centrality at top RHIC energy.

   nucl-exhep-exhep-phEPJC(2021)·15 citations
2. 02*

   International Workshop on Next Generation Gamma-Ray Source

   C. R. Howell🇺🇸 · M. W. Ahmed🇺🇸 · A. Afanasev🇺🇸 · D. Alesini🇮🇹 · J. R. M. Annand🇬🇧 · A. Aprahamian🇺🇸 · D. L. Balabanski🇷🇴 · S. V. Benson🇺🇸 · A. Bernstein🇺🇸 · C. R. Brune🇺🇸 · J. Byrd🇺🇸 · B. E. Carlsten🇺🇸 and 41 other authors

   A workshop on The Next Generation Gamma-Ray Sources sponsored by the Office of Nuclear Physics at the Department of Energy, was held November 17--19, 2016 in Bethesda, Maryland. The goals of the workshop were to identify basic and applied research opportunities at the frontiers of nuclear physics that would be made possible by the beam capabilities of an advanced laser Compton beam facility. To anchor the scientific vision to realistically achievable beam specifications using proven technologies, the workshop brought together experts in the fields of electron accelerators, lasers, and optics to examine the technical options for achieving the beam specifications required by the most compelling parts of the proposed research programs. An international assembly of participants included current and prospective $\gamma$-ray beam users, accelerator and light-source physicists, and federal agency program managers. Sessions were organized to foster interactions between the beam users and facility developers, allowing for information sharing and mutual feedback between the two groups. The workshop findings and recommendations are summarized in this whitepaper.

   nucl-exnucl-thphysics.acc-phJ.Phys.G(2022)·35 citations
3. 03*

   Measurement of the Ar(e,e${}^{\prime }$ p) and Ti(e,e${}^{\prime }$ p) cross sections in Jefferson Lab Hall A

   L. Gu🇺🇸 · D. Abrams🇺🇸 · A. M. Ankowski🇺🇸 · L. Jiang🇺🇸 · B. Aljawrneh🇺🇸 · S. Alsalmi🇸🇦 · J. Bane🇺🇸 · A. Batz🇺🇸 · S. Barcus🇺🇸 · M. Barroso🇺🇸 · O. Benhar🇮🇹 · V. Bellini🇮🇹 and 49 other authors

   The E12-14-012 experiment, performed in Jefferson Lab Hall A, has collected exclusive electron-scattering data (e,e${}^{\prime }$p) in parallel kinematics using natural argon and natural titanium targets. Here, we report the first results of the analysis of the data set corresponding to beam energy of 2,222 MeV, electron scattering angle 21.5 deg, and proton emission angle -50 deg. The differential cross sections, measured with $\sim$4% uncertainty, have been studied as a function of missing energy and missing momentum, and compared to the results of Monte Carlo simulations, obtained from a model based on the Distorted Wave Impulse Approximation.

   nucl-exnucl-thPRC(2021)·22 citations
4. 04*

   A technique to study the elastic and inelastic interaction of quarkonium with hadrons using femtoscopic correlations

   Marzieh Bahmani🇵🇱 · Daniel Kikoła🇵🇱 · Leszek Kosarzewski🇨🇿

   We present a method for the measurement of parameters of elastic and inelastic interactions of charmonium with hadrons. In this technique, we use femtoscopic analysis of charmonium-hadron correlations at low relative momentum and the Lednicky-Lyuboshitz analytical model to extract the interaction parameters. We argue that such a study is already feasible in the LHCb experiment at the LHC, and we discuss the prospects for studies in the STAR at RHIC and other experiments at the LHC.

   ↳ hep-phhep-exnucl-exEPJC(2021)·2 citations
5. 05*

   \boldmath{${\rm Y}$} and \boldmath{${\eta }_b$} mass shifts in nuclear matter

   G. N. Zeminiani🇧🇷 · J. J. Cobos-Martinez🇲🇽 · K. Tsushima🇧🇷

   We estimate the ${\rm Y}$, ${\eta }_b$ and $B^{\ast }$ meson mass shifts in symmetric nuclear matter. The interest is, whether the strengths of the bottomonium-(nuclear matter) and charmonium-(nuclear matter) interactions are similar or different. This is because, each ($J/\Psi ,{\rm Y}$) and (${\eta }_c,{\eta }_b$) meson group is usually assumed to have very similar properties based on the heavy charm and bottom quark masses. The estimate for the ${\rm Y}$ is made using an SU(5) effective Lagrangian and the anomalous coupling one, by studying the $BB$, $B{B}^{\ast }$, and $B^{\ast }{B}^{\ast }$ meson loop contributions for the self-energy. As for the ${\eta }_b$, we include the $B{B}^{\ast }$ and $B^{\ast }{B}^{\ast }$ meson loop contributions in the self-energy. The in-medium masses of the $B$ and $B^{\ast }$ mesons appearing in the self-energy are calculated by the quark-meson coupling model. An analysis on the $BB$, $B{B}^{\ast }$, and $B^{\ast }{B}^{\ast }$ meson loops in the ${\rm Y}$ mass shift is made by comparing with the corresponding $DD,D{D}^{\ast }$, and $D^{\ast }{D}^{\ast }$ meson loops for the $J/\Psi$ mass shift. Our prediction for the ${\eta }_b$ mass shift is made including only the lowest order $B{B}^{\ast }$ meson loop. The ${\rm Y}$ mass shift, with including only the $BB$ loop, is predicted to be -16 to -22 MeV at the nuclear matter saturation density using the ${\rm Y}BB$ coupling constant determined by the vector meson dominance model with the experimental data, while the ${\eta }_b$ mass shift is predicted to be -75 to -82 MeV with the SU(5) universal coupling constant determined by the ${\rm Y}BB$ coupling constant. Our results show an appreciable difference between the bottomonium-(nuclear matter) and charmonium-(nuclear matter) interaction strengths. We also study the ${\rm Y}$ and ${\eta }_b$ mass shifts in a heavy quark (heavy meson) symmetry limit.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJA(2021)·24 citations
6. 06*

   Update of the Three-fluid Hydrodynamics-based Event Simulator: light-nuclei production in heavy-ion collisions

   M. Kozhevnikova🇷🇺 · Yu. B. Ivanov🇷🇺 · Iu. Karpenko🇨🇿 · D. Blaschke🇵🇱 · O. Rogachevsky🇷🇺

   We present an update of the event generator based on the three-fluid dynamics (3FD), complemented by Ultra-relativistic Quantum Molecular Dynamics (UrQMD) for the late stage of the nuclear collision~-- the three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS). Two modifications are introduced. The THESEUS table of hadronic resonances is made consistent with that of the underlying 3FD model. The main modification is that the generator is extended to simulate the light-nuclei production in relativistic heavy-ion collisions, on the equal basis with hadrons. These modifications are illustrated by applications to the description of available experimental data. The first run of the updated generator revealed a good reproduction of the NA49 data on the light nuclei. The reproduction is achieved without any extra parameters, while the coalescence approach in 3FD requires special tuning of the coalescence coefficients for each light nucleus separately.

   ↳ nucl-thhep-phnucl-exPRC(2021)·15 citations
7. 07*

   Decay properties of the $d^{\ast }(2380)$ hexaquark multiplet

   M. Bashkanov🇬🇧 · G. Clash🇬🇧 · M. Mocanu🇬🇧 · M. Nicol🇬🇧 · D.P. Watts🇬🇧

   The recently discovered $d^{\ast }(2380)$ hexaquark is expected to be the lightest member of an extended SU(3) antidecuplet of hexaquark states. The experimental search for the other heavier and strange partners of the $d^{\ast }(2380)$ in the antidecuplet is a challenging task. Evaluating the most appropriate methodologies necessitates some understanding of the underlying properties of the decuplet states such as mass, width and decay branches. In this paper we provide estimates of these key properties for all decuplet states, extrapolating from information and insights garnered for the $d^{\ast }(2380)$. The predictions form a basis for the design of future discovery experiments.

   ↳ hep-phnucl-ex3 citations
8. 08*

   Reweighted nuclear PDFs using Heavy-Flavor Production Data at the LHC: nCTEQ15_rwHF & EPPS16_rwHF

   Aleksander Kusina🇵🇱 · Jean-Philippe Lansberg🇫🇷 · Ingo Schienbein🇫🇷 · Hua-Sheng Shao🇫🇷

   We present the reweighting of two sets of nuclear PDFs, nCTEQ15 and EPPS16, using a selection of experimental data on heavy-flavor meson [D0, J/psi, J/psi from B and Upsilon(1S)] production in proton-lead collisions at the LHC which were not used in the original determination of these nuclear PDFs. The reweighted PDFs exhibit significantly smaller uncertainties thanks to these new heavy-flavor constraints. We present a comparison with another selection of data from the LHC and RHIC which were not included in our reweighting procedure. The comparison is overall very good and serves as a validation of these reweighted nuclear PDF sets, which we dub nCTEQ15_rwHF & EPPS16_rwHF. This indicates that the LHC and forward RHIC heavy-flavor data can be described within the standard collinear factorization framework with the same (universal) small-x gluon distribution. We discuss how we believe such reweighted PDFs should be used as well as the limitations of our procedure.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2021)·38 citations
9. 09*

   A Model for Crosstalk in Micropattern Gas Detectors

   M. Hohlmann🇺🇸

   Crosstalk characteristics such as pulse amplitude and shape are studied with a simple PSpice model of the capacitive couplings within an MPGD. The crosstalk pulse shape can be understood as due to a CR-differentiator. Crosstalk can occur simultaneously through more than one capacitive coupling path. The crosstalk signals on these paths add differently if the signal is induced via a current source as in normal detector operation or via a voltage source as is often done in benchtop tests with an external voltage pulse generator. A few means for reducing the crosstalk are investigated with the model. It shows that a low-impedance AC path from the amplification electrode that faces the readout structure to ground is important for minimizing crosstalk. This implies a need for a sufficiently large capacitance of that amplification electrode to ground. This result has consequences for how much such an amplification electrode can be segmented without incurring crosstalk.

   ↳ physics.ins-dethep-exnucl-ex1 citation
10. 10*

    Towards complete leading-order predictions for neutrinoless double $\beta$ decay

    Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Martin Hoferichter🇨🇭 · Emanuele Mereghetti🇺🇸

    The amplitude for the neutrinoless double $\beta$ ($0\nu \beta \beta$) decay of the two-neutron system, $nn\to pp{e}^{-}{e}^{-}$, constitutes a key building block for nuclear-structure calculations of heavy nuclei employed in large-scale $0\nu \beta \beta$ searches. Assuming that the $0\nu \beta \beta$ process is mediated by a light-Majorana-neutrino exchange, a systematic analysis in chiral effective field theory shows that already at leading order a contact operator is required to ensure renormalizability. In this work, we develop a method to estimate the numerical value of its coefficient in analogy to the Cottingham formula and validate the result by reproducing the charge-independence-breaking contribution to the nucleon-nucleon scattering lengths. Our central result, while derived in the $\overline{\text{MS}}$ scheme, is given in terms of the renormalized amplitude ${\mathcal{A}}_{\nu }(|\mathbf{p}|,|{\mathbf{p}}^{\prime }|)$, matching to which will allow one to determine the contact-term contribution in regularization schemes employed in nuclear-structure calculations. Our results thus greatly reduce a crucial uncertainty in the interpretation of searches for $0\nu \beta \beta$ decay.

    ↳ nucl-thhep-exhep-lathep-ph+1PRL(2021)·103 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.