Publications

Order by: publication date number of citations

• Speed of sound in dense strong-interaction matter

  Jens Braun, Andreas Geißel, Benedikt Schallmo

  SciPost Phys. Core 7, 015 (2024) · published 5 April 2024 | Toggle abstract · pdf

  We study the speed of sound in strong-interaction matter at zero temperature and in density regimes which are expected to be governed by the presence of a color-superconducting gap. At (very) high densities, our analysis indicates that the speed of sound approaches its asymptotic value associated with the non-interacting quark gas from below, in agreement with first-principles studies which do not take the presence of a color-superconducting gap into account. Towards lower densities, however, the presence of a gap induces an increase of the speed of sound above its asymptotic value. Importantly, even if gap-induced corrections to the pressure may appear small, we find that derivatives of the gap with respect to the chemical potential can still be sizeable and lead to a qualitative change of the density dependence of the speed of sound. Taking into account constraints on the density dependence of the speed of sound at low densities, our general considerations suggest the existence of a maximum in the speed of sound. Interestingly, we also observe that specific properties of the gap can be related to characteristic properties of the speed of sound which are indirectly constrained by observations.

• Jet substructure observables for jet quenching in quark gluon plasma: A machine learning driven analysis

  Miguel Crispim Romão, José Guilherme Milhano, Marco van Leeuwen

  SciPost Phys. 16, 015 (2024) · published 18 January 2024 | Toggle abstract · pdf

  We present a survey of a comprehensive set of jet substructure observables commonly used to study the modifications of jets resulting from interactions with the Quark Gluon Plasma in Heavy Ion Collisions. The JEWEL event generator is used to produce simulated samples of quenched and unquenched jets. Three distinct analyses using Machine Learning techniques on the jet substructure observables have been performed to identify both linear and non-linear relations between the observables, and to distinguish the Quenched and Unquenched jet samples. We find that most of the observables are highly correlated, and that their information content can be captured by a small set of observables. We also find that the correlations between observables are resilient to quenching effects and that specific pairs of observables exhaust the full sensitivity to quenching effects. The code, the datasets, and instructions on how to reproduce this work are also provided.

• An algebraic approach to intertwined quantum phase transitions in the Zr isotopes

  Noam Gavrielov

  SciPost Phys. Proc. 14, 028 (2023) · published 24 November 2023 | Toggle abstract · pdf

  The algebraic framework of the interacting boson model with configuration mixing is employed to demonstrate the occurrence of intertwined quantum phase transitions (IQPTs) in the $_{40}$Zr isotopes with neutron number 52-70. The detailed quantum and classical analyses reveal a QPT of crossing normal and intruder configurations superimposed on a QPT of the intruder configuration from U(5) to SU(3) and a crossover from SU(3) to SO(6) dynamical symmetries.

• Remembering David J. Rowe

  John L. Wood, Piet Van Isacker

  SciPost Phys. Proc. 14, 013 (2023) · published 23 November 2023 | Toggle abstract · pdf

  David Rowe was a highly respected theoretical physicist who made seminal contributions that improved our understanding of the atomic nucleus, in particular of the collective behaviour of its constituent nucleons - results he often obtained with the use of sophisticated group-theoretical methods. He will also be remembered as the (co-)author of monographs on nuclear physics, written with the scientific rigour that was characteristic of his research.

• Emergent symmetries in atomic nuclei: Probing nuclear dynamics and physics beyond the standard model

  Kristina D. Launey, K. S. Becker, G. H. Sargsyan, O. M. Molchanov, M. Burrows, A. Mercenne, T. Dytrych, D. Langr, J. P. Draayer

  SciPost Phys. Proc. 14, 007 (2023) · published 23 November 2023 | Toggle abstract · pdf

  Dominant shapes naturally emerge in atomic nuclei from first principles, thereby establishing the shape-preserving symplectic Sp(3, $\mathbb{R}$) symmetry as remarkably ubiquitous and almost perfect symmetry in nuclei. We discuss the critical role of this emergent symmetry in enabling machine-learning descriptions of heavy nuclei, ab initio modeling of $\alpha$ clustering and collectivity, as well as tests of beyond-the-standard-model physics. In addition, the Sp(3, $\mathbb{R}$) and SU(3) symmetries provide relevant degrees of freedom that underpin the ab initio symmetry-adapted no-core shell model with the remarkable capability of reaching nuclei and reaction fragments beyond the lightest and close-to-spherical species.

• Phases of cold holographic QCD: Baryons, pions and rho mesons

  Nicolas Kovensky, Aaron Poole, Andreas Schmitt

  SciPost Phys. 15, 162 (2023) · published 13 October 2023 | Toggle abstract · pdf

  We improve the holographic description of isospin-asymmetric baryonic matter within the Witten-Sakai-Sugimoto model by accounting for a realistic pion mass, computing the pion condensate dynamically, and including rho meson condensation by allowing the gauge field in the bulk to be anisotropic. This description takes into account the coexistence of baryonic matter with pion and rho meson condensates. Our main result is the zero-temperature phase diagram in the plane of baryon and isospin chemical potentials. We find that the effective pion mass in the baryonic medium increases with baryon density and that, as a consequence, there is no pion condensation in neutron-star matter. Our improved description also predicts that baryons are disfavored at low baryon chemical potentials even for arbitrarily large isospin chemical potential. Instead, rho meson condensation sets in on top of the pion condensate at an isospin chemical potential of about $9.4 m_\pi$. We further observe a highly non-monotonic phase boundary regarding the disappearance of pion condensation.

• Universal geometry of two-neutron halos and Borromean Efimov states close to dissociation

  Pascal Naidon

  SciPost Phys. 15, 123 (2023) · published 29 September 2023 | Toggle abstract · pdf

  The geometry of Borromean three-body halos, such as two-neutron halo nuclei or triatomic molecules close to dissociation, is investigated using a three-body model. This model enables to analytically derive the universal geometric properties found recently within an effective-field theory for halos made of a core and two resonantly-interacting particles [Phys. Rev. Lett., 128, 212501 (2022)]. It is shown that these properties not only apply to the ground three-body state, but also to all the excited (Efimov) states where the core-particle interaction is resonant. Furthermore, a universal geometry persists away from the resonant regime between the two particles, for any state close to the three-body threshold. This "halo universality", which applies equally to all states, is different from the Efimov universality, which is only approximate for the ground state. It is explained by the separability of the hyper-radius and hyper-angles close to the three-body dissociation threshold.

• Inferring nuclear structure from heavy isobar collisions using Trajectum

  Govert Nijs, Wilke van der Schee

  SciPost Phys. 15, 041 (2023) · published 1 August 2023 | Toggle abstract · pdf

  Nuclei with equal number of baryons but varying proton number (isobars) have many commonalities, but differ in both electric charge and nuclear structure. Relativistic collisions of such isobars provide unique opportunities to study the variation of the magnetic field, provided the nuclear structure is well understood. In this work we simulate collisions using several state-of-the-art parametrizations of the $^{96}_{40}$Zr and $^{96}_{44}$Ru isobars and show that a comparison with the exciting STAR measurement [arXiv:2109.00131] of ultrarelativistic collisions can uniquely identify the structure of both isobars. This not only provides an urgently needed understanding of the structure of the Zirconium and Ruthenium isobars, but also paves the way for more detailed studies of nuclear structure using relativistic heavy ion collisions.

  7 citations

• CJ15 global PDF analysis with new electroweak data from the STAR and SeaQuest experiments

  Sanghwa Park, Alberto Accardi, Xiaoxian Jing, Joseph F. Owens

  SciPost Phys. Proc. 8, 177 (2023) · published 11 July 2023 | Toggle abstract · pdf

  We present updates to a recent CTEQ-Jefferson Lab (CJ) global analysis of parton distribution functions with a new set of electroweak data that provide unique access to quark flavor separation in the proton. In particular, recent $W$ and $Z$ boson measurements from the STAR experiment at RHIC put additional constraints on light quarks and antiquarks near the valence regime. The new measurement of the Drell-Yan lepton pair production ratio in $p+p$ and $p+d$ collisions by the SeaQuest experiment at Fermilab extends the large-$x$ coverage of the previous E866 experiment and sheds new light on the light antiquarks distribution. In this report, the impact of these new data sets on parton distribution functions will be presented with emphasis given to the flavor asymmetry of the light antiquark sea at large values of the parton momentum $x$.

  1 citation

• Impact of nuclear structure from shell model calculations on nuclear responses to WIMP elastic scattering for $^{19}$F and $^{nat}$Xe targets

  Raghda Abdel Khaleq, Cedric Simenel, Andrew E. Stuchbery

  SciPost Phys. Proc. 12, 062 (2023) · published 5 July 2023 | Toggle abstract · pdf

  Non-relativistic effective field theory (NREFT) is one approach used for describing the interaction of WIMPs with ordinary matter. Among other factors, these interactions are expected to be affected by the structure of the atomic nuclei in the target. The sensitivity of the nuclear response components of the WIMP-nucleus scattering amplitude is investigated using shell model calculations for $^{19}$F and $^{nat}$Xe. Resulting integrated nuclear response values are shown to be sensitive to some specifics of the nuclear structure calculations.