Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sensitivity of flow harmonics to sub-nucleon scale fluctuations in heavy
  ion collisions   In this paper a new procedure to smooth out the initial energy densities of
hydrodynamics is employed to show that the initial spatial eccentricities
$\varepsilon_{m,n}$, which drive the final state flow harmonics $v_n$, are
remarkably robust with respect to variations of the underlying scale of initial
energy density spatial gradients, $\lambda$, in nucleus-nucleus collisions. For
$\sqrt{s}=2.76$ TeV Pb+Pb collisions, the $\varepsilon_{m,n}$'s (across
centrality classes) change by less than $10\%$ if the scale of fluctuations is
varied from $0.1$ to $1$ fm. We show, using the 2+1 Lagrangian hydrodynamic
code, v-USPhydro, that this robustness is transferred to the final $v_n$'s
computed within event by event viscous hydrodynamics. This indicates that the
flow harmonics in nucleus-nucleus collisions are not yet particularly sensitive
to the underlying microscopic sub-nucleon physics below the confinement scale.
On the other hand, the eccentricities of top $1\%$ high multiplicity
$\sqrt{s}=5.02$ TeV p+Pb collisions are found to be very sensitive to
sub-nucleonic scale fluctuations, which should be contrasted with the
robustness found in peripheral Pb+Pb collisions with the same multiplicity.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: supr-con