Nuclear Experiment

New submissions

[ total of 12 entries: 1-12 ]
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New submissions for Fri, 27 Mar 20

[1]  arXiv:2003.11572 [pdf, ps, other]
Title: Structure of high-lying levels populated in the $^{96}$Y $\rightarrow ^{96}$Zr $β$ decay
Subjects: Nuclear Experiment (nucl-ex)

The nature of $J^{\pi}=1^-$ levels of $^{96}$Zr below the $\beta$-decay $Q_{\beta}$ value of $^{96}$Y has been investigated in high-resolution $\gamma$-ray spectroscopy following the $\beta$ decay as well as in a campaign of inelastic photon scattering experiments. Branching ratios extracted from $\beta$ decay allow the absolute $E1$ excitation strength to be determined for levels populated in both reactions. The combined data represents a comprehensive approach to the wavefunction of $1^-$ levels below the $Q_{\beta}$ value, which are investigated in the theoretical approach of the Quasiparticle Phonon Model. This study clarifies the nuclear structure properties associated with the enhanced population of high-lying levels in the $^{96}$Y$_{gs}$ $\beta$ decay, one of the three most important contributors to the high-energy reactor antineutrino spectrum.

Cross-lists for Fri, 27 Mar 20

[2]  arXiv:2003.11264 (cross-list from hep-ph) [pdf, other]
Title: Joint lattice QCD - dispersion theory analysis confirms the top-row CKM unitarity deficit
Comments: 6 pages, 5 figures, 1 table
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

Recently, the first ever lattice computation of the $\gamma W$-box radiative correction to the rate of the semileptonic pion decay allowed for a reduction of the theory uncertainty of that rate by a factor of $\sim3$. A recent dispersion evaluation of the $\gamma W$-box correction on the neutron also led to a significant reduction of the theory uncertainty, but shifted the value of $V_{ud}$ extracted from the neutron and superallowed nuclear $\beta$ decay, resulting in a deficit of the CKM unitarity in the top row. A direct lattice computation of the $\gamma W$-box correction for the neutron decay would provide an independent cross-check for this result but is very challenging. Before those challenges are overcome, we propose a hybrid analysis, converting the lattice calculation on the pion to that on the neutron by a combination of dispersion theory and phenomenological input. The new prediction for the universal radiative correction to free and bound neutron $\beta$-decay reads $\Delta_R^V=0.02477(24)$, in excellent agreement with the dispersion theory result $\Delta_R^V=0.02467(22)$. Combining with other relevant information, the top-row CKM unitarity deficit persists.

[3]  arXiv:2003.11321 (cross-list from nucl-th) [pdf, other]
Title: Self-consistent Green's function theory for atomic nuclei
Authors: Vittorio Somà
Comments: 31 pages, 10 figures, submitted to 'Frontiers in Physics'
Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Chemical Physics (physics.chem-ph)

Nuclear structure theory has recently gone through a major renewal with the development of ab initio techniques that can be applied to a large number of atomic nuclei, well beyond the light sector that had been traditionally targeted in the past. Self-consistent Green's function theory is one among these techniques. The present work aims to give an overview of the self-consistent Green's function approach for atomic nuclei, including examples of recent applications and a discussion on the perspectives for extending the method to nuclear reactions, doubly open-shell systems and heavy nuclei.

[4]  arXiv:2003.11510 (cross-list from physics.ins-det) [pdf, other]
Title: Coherent Elastic Neutrino-Nucleus Scattering with directional detectors
Comments: 14 pages, 11 figures
Subjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

We study the sensitivity of detectors with directional sensitivity to coherent elastic neutrino-nucleus scattering (CE$\nu$NS), and how these detectors complement measurements of the nuclear recoil energy. We consider stopped pion and reactor neutrino sources, and use gaseous helium and fluorine as examples of detector material. We generate Standard Model predictions, and compare to scenarios that include new, light vector or scalar mediators. We show that directional detectors can provide valuable additional information in discerning new physics, and we identify prominent spectral features in both the angular and the recoil energy spectrum for light mediators, even for nuclear recoil energy thresholds as high as $\sim 50$ keV. Combined with energy and timing information, directional information can play an important role in extracting new physics from CE$\nu$NS experiments.

[5]  arXiv:2003.11655 (cross-list from hep-ph) [pdf, other]
Title: Nucleon elastic form factors at accessible large spacelike momenta
Comments: 14 pages, 9 figures, 1 table
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

A Poincar\'e-covariant quark+diquark Faddeev equation is used to compute nucleon elastic form factors on $0\leq Q^2\leq 18 \,m_N^2$ ($m_N$ is the nucleon mass) and elucidate their role as probes of emergent hadronic mass in the Standard Model. The calculations expose features of the form factors that can be tested in new generation experiments at existing facilities, e.g. a zero in $G_E^p/G_M^p$; a maximum in $G_E^n/G_M^n$; and a zero in the proton's $d$-quark Dirac form factor, $F_1^d$. Additionally, examination of the associated light-front-transverse number and anomalous magnetisation densities reveals, inter alia: a marked excess of valence $u$-quarks in the neighbourhood of the proton's centre of transverse momentum; and that the valence $d$-quark is markedly more active magnetically than either of the valence $u$-quarks. The calculations and analysis also reveal other aspects of nucleon structure that could be tested with a high-luminosity accelerator capable of delivering higher beam energies than are currently available.

[6]  arXiv:2003.11728 (cross-list from physics.data-an) [pdf, other]
Title: A Comprehensive Monte Carlo Framework for Jet-Quenching
Authors: R.A. Soltz
Comments: 8 pages, 8 figures, contribution to the Quark Matter 2019 proceedings
Subjects: Data Analysis, Statistics and Probability (physics.data-an); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

This article presents the motivation for developing a comprehensive modeling framework in which different models and parameter inputs can be compared and evaluated for a large range of jet-quenching observables measured in relativistic heavy-ion collisions at RHIC and the LHC. The concept of a framework us discussed within the context of recent efforts by the JET Collaboration, the authors of JEWEL, and the JETSCAPE collaborations. The framework ingredients for each of these approaches is presented with a sample of important results from each. The role of advanced statistical tools in comparing models to data is also discussed, along with the need for a more detailed accounting of correlated errors in experimental results.

[7]  arXiv:2003.11836 (cross-list from hep-ph) [pdf, other]
Title: Searching for New Physics in Two-Neutrino Double Beta Decay
Comments: 28 pages, 6 figures, including appendix
Subjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

Motivated by non-zero neutrino masses and the possibility of New Physics discovery, a number of experiments search for neutrinoless double beta decay. While hunting for this hypothetical nuclear process, a significant amount of two-neutrino double beta decay data has become available. Although these events are regarded and studied mostly as the background of neutrinoless double beta decay, they can be also used to probe physics beyond the Standard Model. In this paper we show how the presence of right-handed leptonic currents would affect the energy distribution and angular correlation of the outgoing electrons in two-neutrino double beta decay. Consequently, we estimate constraints imposed by currently available data on the existence of right-handed neutrino interactions without having to assume their nature. In this way our results complement the bounds coming from the non-observation of neutrinoless double beta decay as they limit also the exotic interactions of Dirac neutrinos. We perform a detailed calculation of two-neutrino double beta decay under the presence of exotic (axial-)vector currents and we demonstrate that current experimental searches can be competitive to existing limits.

Replacements for Fri, 27 Mar 20

[8]  arXiv:1908.07113 (replaced) [pdf, other]
Title: Neutrino Detectors as Tools for Nuclear Security
Comments: 22 pages, 5 figures, published version
Journal-ref: Rev. Mod. Phys. 92 (2020) no.1, 011003
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)
[9]  arXiv:1909.03158 (replaced) [pdf, other]
Title: Studies of J/$ψ$ production at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV
Comments: 27 pages, 9 captioned figures, 1 table, authors from page 22, submitted to JHEP, figures at
Journal-ref: JHEP 2002 (2020) 041
Subjects: Nuclear Experiment (nucl-ex); High Energy Physics - Experiment (hep-ex)
[10]  arXiv:1909.12261 (replaced) [pdf, other]
Title: Catching a glimpse of the parton structure of the bound proton
Comments: 6 pages, 4 figures; minor corrections; references added. Version accepted for publication in Phys. Rev. D, Rapid Communications
Subjects: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
[11]  arXiv:1911.00456 (replaced) [pdf, ps, other]
Title: Charmed hadron chemistry in relativistic heavy-ion collisions
Comments: 6 pages, 5 figures
Subjects: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
[12]  arXiv:2001.04256 (replaced) [pdf, other]
Title: Probing impact-parameter dependent nuclear parton densities from double parton scatterings in heavy-ion collisions
Authors: Hua-Sheng Shao
Comments: 12 pages, 3 figures, 4 tables; v2: journal version (add a new appendix and references)
Journal-ref: Phys. Rev. D 101, 054036 (2020)
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
[ total of 12 entries: 1-12 ]
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