| |
Bhattacharya, A., Dey, C., Kumar, M. C., & Pandey, V. (2025). Next to soft threshold resummation for VH production. Eur. Phys. J.-Spec. Top., , 12pp.
Abstract: We study the threshold effects for the associated production of a Higgs boson with a massive vector boson (V=Z,W)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(V=Z,W)$$\end{document} in the qq<overline>-> V star -> VH\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$q\bar{q} \rightarrow V<^>\star \rightarrow VH$$\end{document} process at the LHC. By leveraging the universality of threshold logarithms and employing soft-virtual (SV) and next-to-soft virtual (NSV) resummation techniques, we compute threshold corrections to next-to-next-to-leading logarithmic accuracy. After matching the resummed predictions to the Next-to-Next-to-Leading order (NNLO) fixed order results, we present the invariant mass distribution to NNLO +NNLL<overline>\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+\overline{\text {NNLL}}$$\end{document} accuracy in QCD for the current LHC energies and the total production cross sections. The VH production channel is crucial for studying the couplings of the Higgs boson to the vector bosons (W, Z) and understanding the mechanism of electroweak symmetry breaking. Precision measurements of this process help test the validity of the standard model (SM) and can reveal potential deviations indicating new physics.
|
|
Song, J., Bayar, M., Li, Y. Y., & Oset, E. (2025). Revisiting the Λc+→K0η reaction: the role of N*(1535),N* and Σ(1620). Eur. Phys. J. C, 85(10), 1114–14pp.
Abstract: We perform a theoretical study of the weak decay Lambda c+-> K0 eta p using a coupled-channel chiral unitary approach that incorporates both pseudoscalar-baryon and vector-baryon interactions. Our framework includes contributions from both internal and external weak emission mechanisms, as well as strong final state interactions. We assume that the N*(1535) and N*(1650 resonances are dynamically generated through meson-baryon scattering and they appear as distinct structures in the eta p invariant mass distributions. A clear peak also appears in the K0p invariant mass distribution around 1620 MeV, associated with the dynamically generated Sigma(1620) resonance. Notably, this work provides the first theoretical description of the simultaneous observation of these two related N* resonances in the same meson-baryon final state. Our results highlight the crucial role of final state interaction and the interplay between different weak decay topologies in shaping the resonance patterns. These findings offer new insights into the nature of nucleon excitations and support the interpretation of N*(1535) and N*(1650) as dynamically generated states. Moreover, the identification of the Sigma(1620) further supports the picture of hadronic molecular structures emerging from meson-baryon interactions in the non-perturbative QCD regime.
|
|
Song, J., Li, Y. Y., & Oset, E. (2025). Molecular states with bottom mesons and multistrange baryons systems. Eur. Phys. J. C, 85(10), 1101–13pp.
Abstract: We investigate molecular states formed by bottom mesons and multistrange baryons from both octet and decuplet flavor representations, using the local hidden gauge approach combined with coupled-channel Bethe-Salpeter equations. Focusing on strangeness sectors S = – 1 -4, we predict several bound states in the S = – 1 I = 1/2 3/2 and S = – 2 I = 0 sectors. No bound states are found in other isospin channels, where the interaction is repulsive, nor in higher strangeness sectors. The binding energies are analyzed under different values of the cutoff regularization parameters, providing estimates of theoretical uncertainties. This study provides concrete predictions to support future experimental investigations and improve understanding of heavy-flavor multistrange exotic hadrons.
|
|
Ternes, C. A., & Tortola, M. (2025). Neutrino magnetic moments: effective versus fundamental parameters. Nucl. Phys. B, 1019, 117107–8pp.
Abstract: The search for neutrino magnetic moments offers a valuable window into physics beyond the Standard Model. However, a common misconception arises in the interpretation of experimental results: the assumption that the so-called effective neutrino magnetic moment is a universal, experiment-independent quantity. In reality, this effective parameter depends on the specific characteristics of each experiment, including the neutrino source, flavor composition or energy spectrum. As a result, the effective magnetic moment derived from solar neutrino data differs fundamentally from that obtained in reactor or accelerator-based experiments. Treating these quantities as directly comparable can lead to misleading conclusions. In this work, we clarify the proper definition of the effective neutrino magnetic moment in various experimental contexts and discuss the implications of this misconception for global analyses and theoretical interpretations.
|
|
NA64 Collaboration(Andreev, Y. M. et al), Molina Bueno, L., & Tuzi, M. (2026). High efficiency veto hadron calorimeter in the NA64 experiment at CERN. Nucl. Instrum. Methods Phys. Res. A, 1081, 170830–10pp.
Abstract: NA64 is a fixed-target experiment at the CERN SPS designed to search for Light particle Dark Matter (LDM) candidates with masses in the sub-GeV range. During the 2016-2022 runs, the experiment obtained the world-leading constraints, leaving, however, part of the well-motivated region of parameter space suggested by benchmark LDM models still unexplored. To further improve sensitivity, as part of the upgrades to the setup of NA64 at the CERN SPS H4 beamline, a prototype veto hadron calorimeter (VHCAL) was installed in the downstream region of the experiment during the 2023 run. The VHCAL, made of Cu-Sc layers, was expected to be an efficient veto against upstream electroproduction of large-angle hadrons or photon-nuclear interactions, reducing the background from secondary particles escaping the detector acceptance. With the collected statistics of 4.4 x 1011 electrons on target (EOT), we demonstrate the effectiveness of this approach by rejecting this background by more than an order of magnitude. This result provides an essential input for designing a full-scale optimized VHCAL to continue running background-free during LHC Run 4, when we expect to collect 1013 EOT. Furthermore, this technique combined with improvements in the analysis enables us to decrease our missing energy threshold from 50 GeV to 40 GeV, thereby enhancing the signal sensitivity of NA64.
|
|
|
