We discuss prompt production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> mesons in proton-proton collisions at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mrow><mn>68.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> energy within the nonrelativistic quantum chromodynamics <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach using different unintegrated gluon distribution functions (UGDFs). We include both direct color-singlet production (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>g</mi></math>) as well as a feed-down from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>γ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>X</mi></math> decays. The production of the decaying mesons <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup></math> is also calculated within the nonrelativistic quantum chromodynamics <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach. Differential distributions in the rapidity and transverse momentum of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> are calculated and compared with experimental data of LHCb collaboration. The LHCb fixed target data allow us to test UGDFs in a new range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>.

Poland

Anna Cisek

Antoni Szczurek

Prompt inclusive production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> mesons at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>68.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> energy within the NRQCD <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach

This work explores the impact of gravitational cracking on energy exchange within a self-gravitating sphere. For such a purpose, we use the isotropic extension of Einstein’s universe solution, modified through gravitational decoupling using extended minimal geometric deformation, which previously exhibited notable energy exchange behavior between its fluid components. This study bridges two critical concepts in the analysis of static self-gravitating spheres within the framework of General Relativity, traditionally examined independently. Our findings indicate that the onset of fractures markedly influences the energy exchange that sustains the sphere. Compared to a system in hydrostatic equilibrium, gravitational cracking significantly accelerates this exchange, occurring inwardly in the inner regions and outwardly in the outer regions of the disturbed system. Notably, the energy exchange intensifies in the outer regions, becoming more pronounced as the relativistic fluids gain energy density.

Ecuador

S. Medina

J. Andrade

D. Santana

Pakistan

Azerbaijan

Tayyab Naseer

Effect of gravitational cracking on energy exchange in relativistic fluids: a first approach

In this work, we constrain the bounce energy scale $$\rho _{s\downarrow }^{1/4}$$ in a generic bouncing-cosmology framework using the probable nanohertz stochastic gravitational-wave signal from NANOGrav 15-year, EPTA DR2, PPTA DR3, and IPTA DR2. A full Bayesian fit to the analytic stochastic-GW spectrum, for the first time, reveals two distinct posterior branches in $$\bigl (\rho _{s\downarrow }^{1/4},\,w_{1}\bigr )$$ : one near $$w_{1}\approx 0.3$$ and another at $$w_{1}\gg 1$$ , where $$w_{1}$$ is the contraction-phase equation of state. We find that current PTA data strongly favor the bounce hypothesis over six conventional SGWB sources, while yielding smaller Bayes factors than its parent dual inflation–bounce scenario as the bounce scale is explicit. Both branches imply $$\rho _{s\downarrow }^{1/4}>M_\textrm{pl}$$ , indicating a trans-Planckian probe. In particular, the $$w_{1}\gg 1$$ branch violates the dominant energy condition, motivating novel early-Universe physics. These results, confirmed by an accelerated machine learning approach, offer a rare observational window into UV completions of cosmology.

China

Junrong Lai

Changhong Li

Probing the bounce energy scale in bouncing cosmologies with pulsar timing arrays

In this article we explore the effect of chemical potential at zero temperature in the implementation of $\textit{in-medium}$ effects in the perturbative sector in finite energy sum rules. For this purpose, we explore the axial, axial-pseudoscalar and pseudoscalar current correlators involving charged pions. The inclusion of non-normal ordered condensates with chemical potential effects in the operator mixing is considered. As a result, the contribution of the operator mixing with chemical potential dependence cancels all the explicit chemical potential contribution of the perturbative sector, aligned with the so-called “silver blaze problem”. We find an abrupt transition when $$\mu =\sqrt{s_0}/2$$ , with $$s_0$$ representing the hadronic continuum threshold. Exploring beyond this critical chemical potential we found similarities with low-energy effective meson models at high chemical potential.

Mexico

Chile

Alfredo Raya

Cristian Villavicencio

Finite-energy sum rules at finite chemical potential and zero temperature

We discuss the low-energy properties of binary superfluids with density-dependent interactions. Adding an intraspecies coupling that induces an explicit soft symmetry breaking, we determine the background pressure, and we show that the low-energy spectrum consists of a massless Nambu-Goldstone boson and a massive (pseudo) Nambu-Goldstone boson. When the background velocities of the two superfluids are transonic, the system is characterized by two distinct acoustic horizons: the hydrodynamic analog of the black hole event horizon. The Hawking-like emission occurring at these horizons produces an effective friction on the fluids. We compute the viscosity-to-entropy ratios close to the two acoustic horizons, finding that the emission of pseudo Nambu-Goldstone bosons violates the bound conjectured by Kovtun, Son, and Starinet.

Italy

Silvia Trabucco

Luca Lepori

Maria Luisa Chiofalo

Massimo Mannarelli

Binary superfluids: Low-energy properties and dissipative processes from spontaneous emission of massive phonons

We investigate the essential properties of gravitational quantum field theory (GQFT) based on spin gauge symmetry, using the general theory of quantum electrodynamics as an example. A constraint equation for the field strength of the gravigauge field is derived, serving as a gravitization equation within the spin-related gravigauge spacetime. This equation reveals how gravitational effects emerge from the non-commutative relation of the gravigauge derivative operator. By transmuting the action from gravigauge spacetime to Minkowski spacetime, we demonstrate that translational invariance results in a vanishing energy-momentum tensor in GQFT when the equations of motion are applied to all fundamental fields, including the gravigauge field. This extends the conservation law of the energy-momentum tensor in quantum field theory to a cancellation law of the energy-momentum tensor in GQFT. As a result, an equivalence between the general gravitational equation and the zero energy-momentum tensor theorem naturally arises in GQFT. Certain aspects of the Poincaré gauge theory are also briefly discussed. Furthermore, a GQFT incorporating the Chern-Simons action in three-dimensional spacetime is developed, based on the inhomogeneous spin gauge symmetry WS(1,2) and the global Poincaré symmetry PO(1,2). This framework provides a basis for exploring its connection to Witten's perspective on three-dimensional gravity.

Yue-Liang Wu

Gravitization equation and zero energy momentum tensor theorem with cancellation law in gravitational quantum field theory

Thermal light dark matter (LDM) with particle masses in the 1 MeV–1 GeV range could successfully explain the observed dark matter abundance as a relic from the primordial Universe. In this picture, a new feeble interaction acts as a “portal” between the Standard Model and LDM particles, allowing for the exploration of this paradigm at accelerator experiments. In the last years, the “missing energy” experiment NA64$\textit{e}$ at CERN SPS (Super Proton Synchrotron) has set world-leading constraints in the vector-mediated LDM parameter space, by exploiting a 100 GeV electron beam impinging on an electromagnetic calorimeter, acting as an active target. In this paper, we report a detailed description of the analysis of a preliminary measurement with a 70 GeV/c positron beam at NA64$\textit{e}$, performed during summer 2023 with an accumulated statistics of 1$\textit{.}$596 × 10 positrons on target (hereafter referred to as $\textit{e}$ OT). This data set was analyzed with the primary aim of evaluating the performance of the NA64$\textit{e}$ detector with a lower energy positron beam, towards the realization of the post-LS3 program. The analysis results, other than additionally probing unexplored regions in the LDM parameter space, provide valuable information towards the future NA64$\textit{e}$ positron campaign.

Yu. Andreev

A. Antonov

M. Ayala Torres

Switzerland

D. Banerjee

B. Banto Oberhauser

V. Bautin

J. Bernhard

P. Bisio

M. Bondì

A. Celentano

N. Charitonidis

P. Crivelli

A. Dermenev

S. Donskov

R. Dusaev

T. Enik

V. Frolov

S. Gertsenberger

S. Girod

S. Gninenko

Germany

M. Hösgen

Y. Kambar

A. Karneyeu

G. Kekelidze

B. Ketzer

D. Kirpichnikov

M. Kirsanov

V. Kramarenko

L. Kravchuk

N. Krasnikov

S. Kuleshov

V. Lyubovitskij

V. Lysan

A. Marini

L. Marsicano

V. Matveev

R. Mena Fredes

R. Mena Yanssen

Spain

L. Molina Bueno

M. Mongillo

D. Peshekhonov

V. Polyakov

Canada

B. Radics

K. Salamatin

V. Samoylenko

H. Sieber

D. Shchukin

O. Soto

V. Tikhomirov

I. Tlisova

A. Toropin

M. Tuzi

P. Volkov

I. Voronchikhin

J. Zamora-Saá

A. Zhevlakov

Proof of principle for a light dark matter search with low-energy positron beams at NA64

We study the Borel plane of the topological string free energy on all hypergeometric one-parameter Calabi-Yau models close to singular points in moduli space, focusing on the location of Borel singularities and the value of the associated Stokes constants. We find in particular that in models which exhibit massless D-branes at a singular point, the central charge of the D-brane close to the singular point coincides with the location of the leading Borel singularity, and the generalized Donaldson-Thomas invariant associated to the charge of the D-brane, in as far as its value is known, coincides with the Stokes constant associated to the Borel singularity.

France

Simon Douaud

Amir-Kian Kashani-Poor

Borel singularities and Stokes constants of the topological string free energy on one-parameter Calabi-Yau threefolds

A loosely bound hadronic molecule produced by a relativistic heavy-ion collision has been described as a “snowball in hell” since it emerges from a hadron resonance gas whose temperature is orders of magnitude larger than the binding energy of the molecule. This remarkable phenomenon can be explained in terms of a novel thermodynamic variable called the “contact” that is conjugate to the binding momentum of the molecule. The production rate of the molecule can be expressed in terms of the contact density at the kinetic freeze-out of the hadron resonance gas. It approaches a nonzero limit as the binding energy goes to 0.

United States

Eric Braaten

Kevin Ingles

Justin Pickett

Explaining Snowball-in-Hell Phenomena in Heavy-Ion Collisions Using a Novel Thermodynamic Variable

The jet quenching parameter and energy loss of light and heavy quarks have been investigated in the framework of holographic quantum chromodynamics (QCD) models with a critical end point (CEP) at finite baryon chemical potential in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>f</mi></msub><mo>=</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>+</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>+</mo><mn>1</mn><mo>+</mo><mn>1</mn></math> systems. The properties of the jet quenching parameter and energy loss around phase boundary have been carefully studied. It is found that the dimensionless jet quenching parameter and the energy loss of light and heavy quarks exhibit evident features around the phase boundary. Specifically, all these quantities increase rapidly near the CEP phase transition temperature <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>CEP</mi></mrow></msub></math> with fixed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mrow><mi>CEP</mi></mrow></msub></math>. Moreover, the velocity dependent behavior of heavy quark energy loss differs significantly from charged particle energy loss in quantum electrodynamics (QED) matter. For electromagnetic interaction, the energy loss of charged particle can be described by the Bethe-Bloch formula and the Lindhand-Scharff-Schiott theory at low and high velocities, respectively. However, the heavy quark energy loss at CEP is approximately proportional to velocity at low velocities and aligns with Bjorken’s results at high velocities, which indicates that the heavy quark energy loss is predominantly collisional at low velocities and gluon radiation dominant at high velocities. For light quark energy loss, the behavior of the energy loss per unit length and the total energy loss differs significantly. However, the total energy loss and stopping distance exhibit similar behavior. This implies that the stopping distance predominantly determines the total energy loss. Thus, even with increased energy loss per unit length at higher temperatures or chemical potentials, the total energy loss decreases due to the reduced stopping distance.

Zhibin Li

Danning Li

Mei Huang

Jet quenching and quark energy loss from holographic QCD