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Journal of Physics G: Nuclear and Particle Physics - latest papers

Latest articles for Journal of Physics G: Nuclear and Particle Physics

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  • B − L model in light of the CDF II result
    Recent CDF II collaboration’s result on W mass measurements contradict Standard Model (SM) prediction, requiring new physics to explain this anomaly. Such new physics may manifest through tree-level or loop-level corrections to the mass of the W boson. In this work, we investigate the possibility that the CDF-II result is indicative of new physics not directly changing the W boson mass but rather the Z boson mass. Since the Z boson mass goes as an input into the SM prediction for W boson mass, this change in Z mass ultimately leads to the discrepancy between the CDF-II measurement and the SM expectation. We demonstrate this idea through one of the simplest and most studied U(1) gauge extensions of the SM, namely the gauged U(1)B−L extension. We demonstrate that B − L extended models can explain the revised best-fit values for S, T, and U following the CDF II results. We studied the parameter space of models with and without mixing between neutral gauge bosons. We also reviewed the dark matter constraints and demonstrated that there is parameter space that is compatible with the current W boson mass, relic abundance, and direct detection experiments.

  • Genetic programming for the nuclear many-body problem: a guide
    Genetic Programming (GP) is an evolutionary algorithm that generates computer programs, or mathematical expressions, to solve complex problems. In this Guide, we demonstrate how to use GP to develop surrogate models to mitigate the computational costs of modeling atomic nuclei with ever increasing complexity. The computational burden escalates when uncertainty quantification is pursued, or when observables must be globally computed for thousands of nuclei. By studying three models in which the mean field depends on the total particle density self-consistently, we show that by constructing reduced order models supported by GP one can speed up many-body computations by several orders of magnitude with a negligible loss in accuracy.

  • Large hadron collider signatures of exotic vector-like quarks within the 2-Higgs doublet model type-II
    We study the decay of the exotic Vector-Like Quarks (VLQs) X and Y, with 5/3 and −4/3 units of electric charge, respectively, within the 2-Higgs Doublet Model (2HDM). Building on our previous studies of Vector-Like Top and Bottom quarks, we now investigate the characteristics of X and Y in the alignment limit of a Type-II Yukawa structure and show that, in the framework of such a 2HDM, one can have large non-Standard Model (SM) decay rates of the X and Y states. Our analysis focuses on their potential detection at the Large hadron collider, based on their pair production followed by a variety of both SM and non-SM decay patterns. In order to distinguish between doublet and triplet representations of the VLQs X and Y, we uncover specific signatures that can provide insights into this particular architecture of Beyond the SM physics.

  • Azimuthal fluctuations of magnetic field and its correlation with the matter geometry in Au + Au, Au + Cu and p + Pb collisions
    We investigated the azimuthal fluctuations of the magnetic field and its correlation with matter geometry using event-by-event simulations in three collision systems: symmetric Au + Au collisions, asymmetric Au + Cu collisions, and small system p + Pb collisions. The correlation between the orientation of the magnetic field and the reaction plane enables the detection of the charge azimuthal correlation driven by the chiral magnetic effect (CME). However, the fluctuations arising from the configuration of the magnetic field and initial matter geometry, especially in the central and peripheral regions, suppress the correlation intensity. Therefore, a quantitative factor is introduced to evaluate the suppression of correlation by fluctuations. We found that the difference in factor R between Au + Au and Au + Cu collisions may serve as evidence for the presence of CME. The correlation pattern in the small system differs markedly from that in the other two collision systems. The orientation of the magnetic field and event plane are fully random in small systems with high multiplicities and only weakly correlated in those with low multiplicities.

  • Dineutron clusters in 7He and 8He structure
    The hyper-radial barrier strongly hinders formation of more than three clusters. We investigate how well the dominating cluster components in 7He and 8He, respectively can be described as α+n+2n and α+2n+2n, where 2n is the dineutron. Effective interactions compatible with 5He and 6He are used. We vary the lesser known n-2n and 2n-2n interactions, where very small strengths are required. We provide energies, radii, and partial wave decomposition of all computed, predicted or measured, ground and resonance states. We predict substructures within each of the three-body quantum states. We also calculate the neutron-structure sensitive invariant mass spectrum of the four-nucleon system, after fast removal of the α-particle from 8He. We show that all available experimental information are fairly well reproduced. Very little room is left for variation of the effective interaction parameters. Thus, the dominating features of the subsequently derived reaction and structure properties are well supported.