87 research outputs found
Symmetric cumulants and event-plane correlations in Pb+Pb collisions
The ALICE Collaboration has recently measured the correlations between
amplitudes of anisotropic flow in different Fourier harmonics, referred to as
symmetric cumulants. We derive approximate relations between symmetric
cumulants involving and and the event-plane correlations measured
by ATLAS. The validity of these relations is tested using event-by-event
hydrodynamic calculations. The corresponding results are in better agreement
with ALICE data than existing hydrodynamic predictions. We make quantitative
predictions for three symmetric cumulants which are not yet measured.Comment: 6 pages. Minor revision: error bars in Fig.2 have been correcte
Separating the impact of nuclear skin and nuclear deformation in high-energy isobar collisions
Bulk nuclear structure properties, such as radii and deformations, leave
distinct signatures in the final state of relativistic heavy-ion collisions.
Isobaric collisions offer an easy route to establish explicit connections
between the colliding nuclei's structure and the observable outcomes. Here, we
investigate the effects of nuclear skin thickness and nuclear deformations on
the elliptic flow () and its fluctuations in high-energy
Ru+Ru and Zr+Zr collisions. Our findings reveal
that the difference in skin thickness between these isobars only influences the
inherent ellipticity of the collision systems, . In
contrast, differences in nuclear deformations solely impact the fluctuations of
around . Hence, we have identified a data-driven
method to disentangle the effects of nuclear skin and nuclear deformations,
marking a significant step toward assessing the consistency of nuclear
phenomena across energy scales.Comment: 7 pages, 3 figures plus an appendi
The shape of gold
Having a detailed theoretical knowledge of the low-energy structure of the
heavy odd-mass nucleus Au is of prime interest as the structure of this
isotope represents an important input to theoretical simulations of collider
experiments involving gold ions performed worldwide at relativistic energies.
In the present article, therefore, we report on new results on the structure of
Au obtained from state-of-the-art multi-reference energy density
functional (MR-EDF) calculations. Our MR-EDF calculations were realized using
the Skyrme-type pseudo-potential SLyMR1, and include beyond mean-field
correlations through the mixing, in the spirit of the Generator Coordinate
Method (GCM), of particle-number and angular-momentum projected triaxially
deformed Bogoliubov quasi-particle states. Comparison with experimental data
shows that the model gives a reasonable description of Au with in
particular a good agreement for most of the spectroscopic properties of the
ground state. From the collective wave function of the correlated
state, we compute an average deformation and
for the ground state. We use this result to
construct an intrinsic shape of Au representing a
microscopically-motivated input for precision simulations of the associated
collider processes. We discuss, in particular, how the triaxiality of this
nucleus is expected to impact Au+Au collision experiments at
ultrarelativistic energy.Comment: 16 pages, 6 figure
Structure of Xe through multi-reference energy density functional calculations
Recently, values for the Kumar quadrupole deformation parameters of the
nucleus Xe have been computed from the results of a Coulomb excitation
experiment, indicating that this xenon isotope has a prominent triaxial ground
state. Within a different context, it was recently argued that the analysis of
particle correlations in the final states of ultra-relativistic heavy-ion
collisions performed at the Large Hadron Collider (LHC) points to a similar
structure for the adjacent isotope, Xe. In the present work, we report
on state-of-the-art multi-reference energy density functional calculations that
combine projection on proton and neutron number as well as angular momentum
with shape mixing for the three isotopes Xe using the
Skyrme-type pseudo-potential SLyMR1. Exploring the triaxial degree of freedom,
we demonstrate that the ground states of all three isotopes display a very
pronounced triaxial structure. Moreover, comparison with experimental results
shows that the calculations reproduce fairly well the low-energy excitation
spectrum of the two even-mass isotopes. By contrast, the calculation of
Xe reveals some deficiencies of the effective interaction.Comment: 26 pages, 17 figure
Imaging the initial condition of heavy-ion collisions and nuclear structure across the nuclide chart
A major goal of the hot QCD program, the extraction of the properties of the
quark gluon plasma (QGP), is currently limited by our poor knowledge of the
initial condition of the QGP, in particular how it is shaped from the colliding
nuclei. To attack this limitation, we propose to exploit collisions of selected
species to precisely assess how the initial condition changes under variations
of the structure of the colliding ions. This knowledge, combined with
event-by-event measures of particle correlations in the final state of
heavy-ion collisions, will provide in turn a new way to probe the collective
structure of nuclei, and to confront and exploit the predictions of
state-of-the-art ab initio nuclear structure theories. The US nuclear community
should capitalize on this interdisciplinary connection by pursuing collisions
of well-motivated species at high-energy colliders.Comment: 23 pages, 6 figure
Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia
Observing the deformation of nuclei with relativistic nuclear collisions
International audienceI show that particle collider experiments on relativistic nuclear collisions can serve as direct probes of the deformation of the colliding nuclear species. I argue that collision events presenting very large multiplicities of particles and very small values of the average transverse momentum of the emitted hadrons probe collision geometries in which the nuclear ellipsoids fully overlap along their longer side. By looking at these events one selects interaction regions whose elliptic anisotropy is determined by the deformed nuclear shape, which becomes accessible experimentally through the measurement of the elliptic flow of outgoing hadrons
Constraining the quadrupole deformation of atomic nuclei with relativistic nuclear collisions
International audiencePreliminary data by the STAR collaboration at the BNL Relativistic Heavy Ion Collider shows that the elliptic flow, v2, and the average transverse momentum, 〈pt〉, of final-state hadrons produced in high-multiplicity U238+U238 collisions are negatively correlated. This observation brings experimental evidence of a significant prolate deformation, β≈0.3, in the colliding U238 nuclei. I show that a quantitative description of this new phenomenon can be achieved within the hydrodynamic framework of heavy-ion collisions, and that thus such kind of data in the context of high-energy nuclear experiments can help constrain the quadrupole deformation of the colliding species
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