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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 469 records · Page 26

Centrality dependence of high energy jets in p + Pb collisions at energies available at the CERN Large Hadron Collider

We investigate the recently measured centrality dependence of high energy jets in proton-lead collisions at the LHC. Here, we hypothesize that events with jets of very high energy (a few hundred GeV) are characterized by a suppressed number of soft particles, thus shifting these events into more peripheral bins. This naturally results in the suppression (enhancement) of the nuclear modification factor, R p A, in central (peripheral) collisions. Our calculations suggest that a moderate suppression of the order of 20%, for 10 3 GeV jets, can quantitatively reproduce the experimental data. Finally, we further extract the suppression factor as a function of jet energy and test our conjecture using available R p A data for various centralities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Spectra and flow of light nuclei in relativistic heavy ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

Within the framework of the coalescence model based on the phase-space distributions of protons and neutrons generated from the iebe-vishnu hybrid model with ampt initial conditions, we study the spectra and elliptic flow of deuterons and helium-3 in relativistic heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Larger Hadron Collider (LHC). Results from our model calculations for Au+Au collisions at √ s NN = 200 GeV at RHIC and Pb+Pb collisions at √ s NN = 2.76 TeV at the LHC are compared with available experimental data. Good agreements are generally seen between theoretical results and experimental data, except that the calculated yield of helium-3 in Pb+Pb collisions at √ s NN = 2.76 TeV underestimates the data by about a factor of 2. Possible reasons for these discrepancies are discussed. Here, we also make predictions on the spectra and elliptic flow of deuterons and helium-3 in Pb+Pb collisions at √ s NN = 5.02 TeV that are being studied at LHC.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Landau-Pomeranchuk-Midgal effect and charm production in p p collisions at energies available at the CERN Large Hadron Collider using the parton cascade model

We study the impact of the Landau-Pomeranchuk-Midgal (LPM) effect on the dynamics of parton interactions in proton-proton collisions at energies available at the CERN Large Hadron Collider. For our investigation we utilize a microscopic kinetic theory based on the Boltzmann equation. The calculation traces the space-time evolution of the cascading partons interacting via semihard pQCD scatterings and fragmentations. We focus on the impact of the LPM effect on the production of charm quarks, since their production is exclusively governed by processes well described in our kinetic theory. Furthermore, the LPM effect is found to become more prominent as the collision energy rises and at central rapidities, and may significantly affect the model's predicted charm distributions at low momenta.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Measurement of 𝑑 2⁢ 𝜎/𝑑⁢|$\vec{q}$|⁢𝑑⁢𝐸 avail in charged current 𝜈 𝜇 -nucleus interactions at ⟨𝐸 𝜈 ⟩=1.86 GeV using the NOvA Near Detector

Double- and single-differential cross sections for inclusive charged-current 𝜈 𝜇 -nucleus scattering are reported for the kinematic domain 0 to 2 GeV/𝑐 in three-momentum transfer and 0 to 2 GeV in available energy, at a mean 𝜈 𝜇 energy of 1.86 GeV. The measurements are based on an estimated 995,760 𝜈 𝜇 charged-current (CC) interactions in the scintillator medium of the NOvA Near Detector. The subdomain populated by 2-particle-2-hole (2p2h) reactions is identified by the cross section excess relative to predictions for 𝜈 𝜇 -nucleus scattering that are constrained by a data control sample. Models for 2-particle-2-hole processes are rated by 𝜒 2 comparisons of the predicted-versus-measured 𝜈 𝜇 CC inclusive cross section over the full phase space and in the restricted subdomain. Shortfalls are observed in neutrino generator predictions obtained using the theory-based València and SuSAv2 2p2h models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Reconsidering seismological constraints on the available parameter space of macroscopic dark matter

Using lunar seismological data, constraints are proposed on the available parameter space of macroscopic dark matter (macros). Here we show that actual limits are considerably weaker by considering in greater detail the mechanism through which macro impacts generate detectable seismic waves, which have wavelengths considerably longer than the diameter of the macro. We show that the portion of the macro parameter space that can be ruled out by current seismological evidence is considerably smaller than previously reported, and specifically that candidates with greater than or equal to nuclear density are not excluded by lunar seismology.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗