Augustin Sabio Vera

We show that rank-ordered jet rapidity distributions provide simple probes of high-energy QCD dynamics at the LHC. Comparing the Balitsky-Fadin-Kuraev-Lipatov-based Monte Carlo () to standard event generators based on collinear factorization and Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) parton showers (8, 7) in inclusive dijet topologies at 13 TeV, we find clear shape differences. While inclusive distributions can be very similar, rank-ordered spectra reveal that populates the rapidity interval more democratically, whereas DGLAP showers exhibit stronger edge enhancement and central concentration. We quantify the separation using the total-variation and one-dimensional Wasserstein distances between normalized histograms. The separation persists when applying the harder selection p T , j > 60 GeV and H T 2 > 250 GeV . Rank-ordered rapidity distributions thus compress exclusive multijet information into simple histograms, offering a new handle on high-energy radiation patterns measurable with existing data.

After the end of World War II, the commitment to confine scientific activities in universities and research institutions to peaceful and civilian purposes has entered, in the form of {\it Civil Clauses}, the charters of many research institutions and universities. In the wake of recent world events, the relevance and scope of such Civil Clauses has been questioned in reports issued by some governments and by the EU Commission, a development that opens the door to a possible blurring of the distinction between peaceful and military research. This paper documents the reflections stimulated by a panel discussion on this issue recently organized by the Science4Peace Forum. We review the adoptions of Civil Clauses in research organizations and institutions in various countries, present evidence of the challenges that are emerging to such Civil Clauses, and collect arguments in favour of maintaining the purely civilian and peaceful focus of public (non-military) research.

In high-energy particle physics, the study of particle-particle correlations in proton-proton and heavy-ion collisions constitutes a pivotal frontier in the effort to understand the fundamental dynamics of the strong force. To the best of our knowledge, we employ for the first time the Balitsky-Fadin-Kuraev-Lipatov dynamics implemented in a Monte Carlo code in momentum space to compute final-state correlations in proton-proton collisions. Our present work aims to investigate whether the particular dynamics of the high-energy limit of QCD can contribute to the long-range rapidity correlations and the enigmatic ridge effect in proton-proton collisions. Published by the American Physical Society 2024

Quantum properties of the state associated to the gluon Green’s function in the Balitsky-Fadin-Kuraev-Lipatov approach are studied using a discretization in virtuality space. Considering the coupling constant as imaginary, its density matrix corresponds to a pure state for any energy. Nonlinear corrections due to high gluon densities are modeled through a suppression of infrared modes in the Hamiltonian making it no longer Hermitian. This introduces quantum decoherence into the evolution equation. When the coupling is real this leads to unbounded normalization of states which becomes bounded for sufficient saturation of infrared modes. Physical quantum properties, such as a purity smaller than one or a positive von Neumann entropy, hence are recovered when the infrared/ultraviolet original symmetry of the formalism is broken. Similarly to the work of Armesto, Domínguez, Kovner, Lublinsky and Skokov in [], an evolution equation of Lindblad type for the normalized density matrix describing the open system is obtained. Published by the American Physical Society 2024

Multi-particle production studies have always been an important tool in the effort to study the properties of the strong force already from the fifties of the previous century. As the center-of-mass energy of present day hadron colliders and in particular the Large Hadron Collider (LHC) has increased enormously over the years and the focus currently is on the study of multi-jet final states, it would be instructive to see whether the early days phenomenological models applied some 50–60 years ago to describe multi-particle production have anything to offer in the study of multi-jet final states as well as whether they offer predictions different from the QCD based ones. In this paper, we will consider events with two jets well separated in rapidity with similar transverse momenta whereas a number of mini-jets or jets is to be found in between these two bounding jets. Such configurations are relevant for the high energy scattering limit of QCD. We fix the final jet multiplicity to take particular values and we report on a first comparison between the predictions of the old multiperipheral Chew-Pignotti model applied for final state jets and those of BFKL. We compare single jet rapidity distributions as well as jet-jet rapidity correlations.

An asymmetric version of the classical Kermack-McKendrick description of an epidemic evolution is presented in terms of four independent parameters. This is enough to obtain an accurate description of the different stages of the COVID-19 pandemia in any country for the reported daily and total number of casualties due to the infection. The asymmetry accounts for lockdown effects introduced to reduce the impact of the epidemic outburst. A set of new variables allows for an analytic study of the evolution of the system before and after the lockdown measures are put in place. A continuous matching is possible for all variables in the system apart from the time dependence of the infection rate. An analytic expression is obtained for this discontinuity which is proposed as a good quantity to gauge the efficiency of the lockdown measures. A study of this variable for different countries is performed.