abstract

We propose a very simple toy model of a \(\mathbb {Z}_2^2\)-supersymmetric quantum system and show, via Klein’s construction, how to understand the system as being an \(N=2\) supersymmetric system with an extra \(\mathbb {Z}_2^2\)-grading. That is, the commutation/anticommutation rules are defined via the standard boson/fermion rules, but the system still has an underlying \(\mathbb {Z}_2^2\)-grading that needs to be taken into account.

abstract

Weakly nonlocal (WNL) Quantum Field Theories (QFTs) may define a new class of UV-completions in particle physics and gravity, without introducing any new elementary particle. One problematic issue is how to realize spontaneous symmetry breaking without introducing an infinite tower of ghosts in the perturbative spectrum. In this article, a WNL extension of the Standard Model (SM) is proposed: the Fuzzy Standard Model (FSM). It is a smooth deformation of the SM based on covariant star-products of fields. This new formalism realizes electroweak symmetry breaking without ghosts at tree-level. We give evidence that the FSM exhibits Vainshtein screening, aka classicalization, in the deep-UV. This could solve the electroweak hierarchy problem if it occurs at the TeV-scale.

abstract

The fractal and phase transitional properties of each type of pions (i.e. \(\pi ^{\pm ,0}\)) through one-dimensional \(\eta \)-space, at an energy of \(\sqrt {s}=13\) TeV, have been studied with the help of the Scaled Factorial Moment (SFM) framework. To generate simulated data sets for \(pp\) collisions under the minimum bias (MB) condition at \(\sqrt {s}=13\) TeV, we have employed the Monte Carlo-based event simulator PYTHIA. Various parameters such as the Levy index \((\mu )\), degree of multifractality \((r)\), anomalous fractal dimension \((d_q)\), multifractal specific heat \((c)\), and critical exponent \((\nu )\) have been calculated. To study the Bose–Einstein (BE) effect due to identical particles (here pions), we have also derived these parameters for mixed-pion pairs (i.e. \(\{\pi ^{+},\pi ^{-}\}\), \(\{\pi ^{+},\pi ^{0}\}\), and \(\{\pi ^{-},\pi ^{0}\}\)) and we find that the effects of identical particles weakened for the mixture with respect to the individual distributions. The quest for the quark–hadron phase transition has also been conducted within the framework of the Ginzburg–Landau (GL) theory of second-order phase transition. Analysis revealed that for PYTHIA-generated MB events, there is a clear indication of the quark–hadron phase transition according to the GL theory. Furthermore, the values of the multifractal specific heat (\(c\)) for each \(\pi ^{+}, \pi ^{-}, \pi ^{0}\), and the mixture-pair data sets of pions generated by the PYTHIA model at MB condition indicate a transition from multifractality to monofractality in \(pp\) collisions at \(\sqrt {s}=13\) TeV.

abstract

This study aimed at investigating the impact of temperature effects on participating nuclei during fusion reactions and emphasized the need for employing dynamic models to improve the accuracy of static approaches in the fusion process. To achieve this, the researchers utilized the improved quantum molecular dynamics model (ImQMD). Previous research on the influence of temperature on nuclear reactions has shown that static approaches can estimate the temperature of compound nuclei at the point of statistical pre-equilibrium, but they are limited when it comes to the fusion reaction process. To conduct a more detailed study, various methods based on statistical ensembles have been introduced. One of the oldest techniques used to determine nuclear temperature is Weisskopf’s theory, which has been widely applied in temperature studies of various nuclear reactions using the proximity potential. This highlights the importance of considering temperature in the reaction process. However, due to certain limitations, alternative approaches for studying temperature effects have been explored. The ImQMD model, known for its successful capture of dynamic reaction information, provides an opportunity to investigate the temperature effects on compound nuclei during fusion processes. A comparison between the results obtained using the ImQMD model and other statistical models such as Weisskopf’s theory and codes like GEMINI indicates that the dynamic ImQMD model is valuable for examining temperature fluctuations during interactions, unlike static approaches that describe nuclear processes before reaching statistical pre-equilibrium.