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Installation and interconnection work of the IT String cold masses and cold powering system
No full textThe photos capture installation and interconnection work of the HL-LHC IT String cold masses and cold powering system
HH production at LHC
No full textHiggs boson pair production (HH) plays a central role in probing the Higgs boson self-interactions, which are key to understanding the shape of the Higgs potential and the mechanism of electroweak symmetry breaking. This talk presents the latest results from the ATLAS and CMS experiments on non-resonant Higgs boson pair production, based on the full Run 2 dataset collected at\sqrt{s} = 13 TeV, These analyses provide sensitivity to the Higgs boson self-coupling and the quartic VVHH coupling, offering key tests of the Higgs sector beyond single-Higgs measurements. The talk further includes projections for future sensitivity at the High-Luminosity LHC, outlining the expected improvements and challenges ahead
Black holes with electroweak hair: The detailed derivation
No full textWe present a very detailed derivation of solutions describing hairy black holes within the gravity-coupled Weinberg-Salam theory, which were previously reported in Gervalle and Volkov [Black holes with electroweak hair, Phys. Rev. Lett. 133, 171402 (2024)]. These black holes support a strong magnetic field that polarizes the electroweak vacuum and creates a condensate of massive fields carrying superconducting currents along the black hole horizon. The currents, in turn, generate a “corona” of magnetic vortex segments attached to the horizon at both ends. The condensate and corona together constitute the black hole hair. The extremal solutions approach, in the far field, the magnetic Reissner-Nordström configuration, with a total mass that is lower than the total charge, M<|Q|, due to the negative Zeeman energy of the condensate. This makes the removal of the hair energetically unfavorable. The maximally hairy black holes exhibit masses comparable to terrestrial values, with approximately 11% of their total mass stored in the hair. Given that these solutions arise within a well-tested theoretical framework, they are likely to have physical relevance.We present a very detailed derivation of solutions describing hairy black holes within the gravity-coupled Weinberg-Salam theory, which were previously reported in \href{https://doi.org/10.1103/PhysRevLett.133.171402}{Phys.Rev.Lett. 133 (2024) 171402}. These black holes support a strong magnetic field that polarizes the electroweak vacuum and creates a condensate of massive fields carrying superconducting currents along the black hole horizon. The currents, in turn, generate a ``corona'' of magnetic vortex segments attached to the horizon at both ends. The condensate and corona together constitute the black hole hair. The extremal solutions approach, in the far field, the magnetic Reissner-Nordström configuration, with a total mass that is {\it lower} than the total charge, , due to the negative Zeeman energy of the condensate. This makes the removal of the hair energetically unfavorable. The maximally hairy black holes exhibit masses comparable to terrestrial values, with approximately 11% of their total mass stored in the hair. Given that these solutions arise within a well-tested theoretical framework, they are likely to have physical relevance
Revisiting the theory of spin correlations and entanglement in top pair production at the LHC
No full textRecent ATLAS and CMS studies of spin correlations and entanglement in top pair production at hadron colliders have evidenced some inadequacy in the current modeling of the process of top pair production and decay. It has been argued that one needs to include the effect of a very short-lived pseudoscalar bound state to reconcile the data with the theoretical prediction. In this talk I review the problem, and argue that in fact standard perturbation theory is enough to correctly describe these phenomena, with no need to consider threshold-enhanced corrections to all orders and to deal with bound states formation. A simple quantum mechanical model is used to show that the leading correction due to bound state formation has the same form as other corrections that arise from the continuum right above threshold, and that the combination of the two leads to a well-defined expansion in perturbation theory. Furthermore, by examining the calculation of the process as implemented in current Monte Carlo generators, I show that these corrections, that are of the third subleading order in the strong coupling constant, are tiny, while threshold enhanced corrections of first and second subleading order (not related to bound states) seem to be enough to understand the current discrepancies.</p
Displays of a ttH (H → cc) candidate event seen in the CMS detector
No full textDisplays of an event seen in the CMS detector in 2018 consistent with the production of a top quark-antiquark pair in association with a H boson, which decays into a charm quark-antiquark pair
Charge radii measurements of exotic tin isotopes in the proximity of and
No full textWe report nuclear charge radii for the isotopes Sn104–134, measured using two different collinear laser spectroscopy techniques at ISOLDE-CERN. These measurements clarify the archlike trend in charge radii along the isotopic chain and reveal an odd-even staggering that is more pronounced near the N=50 and N=82 shell closures. The observed local trends are well described by both nuclear density functional theory and valence space in-medium similarity renormalization group calculations. Both theories predict appreciable contributions from beyond-mean-field correlations to the charge radii of the neutron-deficient tin isotopes. The models, however, fall short of reproducing the magnitude of the known B(E2) transition probabilities, highlighting the remaining challenges in achieving a unified description of both ground-state properties and collective phenomena.We report nuclear charge radii for the isotopes Sn, measured using two different collinear laser spectroscopy techniques at ISOLDE-CERN. These measurements clarify the arch-like trend in charge radii along the isotopic chain and reveal an odd-even staggering that is more pronounced near the and shell closures. The observed local trends are well described by both nuclear density functional theory and valence space in-medium similarity renormalization group calculations. Both theories predict appreciable contributions from beyond-mean-field correlations to the charge radii of the neutron-deficient tin isotopes. The models, however, fall short of reproducing the magnitude of the known transition probabilities, highlighting the remaining challenges in achieving a unified description of both ground-state properties and collective phenomena
SUSY Highlight Talk: Recent results in electroweak searches for compressed spectra
No full textSupersymmetry (SUSY) models featuring small mass splittings between one or more particles and the lightest neutralino could solve the hierarchy problem as well as offer a suitable dark matter candidate consistent with the observed thermal-relic dark matter density. However, the detection of SUSY higgsinos at the LHC remains challenging especially if their mass-splitting is O(1 GeV) or lower. Searches are developed using 140 fb of proton-proton collision data collected by the ATLAS detector at a center-of-mass energy =13 TeV to overcome the challenge. Novel techniques are developed exploiting machine-learning techniques, low-momentum leptons or tracks, or topologies consistent with VBF production of the supersymmetric particles. Results are interpreted in terms of SUSY simplified models and, for the first time since the LEP era, sensitivity is achieved in previously uncovered gaps in different ranges of mass-splitting
Exploring the Nuclear Chart via Precision Mass Spectrometry with the TITAN MR-TOF MS
No full textIsotopes at the limits of nuclear existence are of great interest for their critical role in nuclear astrophysical reactions and their exotic structure. Experimentally, exotic nuclides are challenging to address due to their low production cross-sections, overwhelming amounts of contamination, and lifetimes of typically less than a second. To this end, a Multiple-Reflection Time-of-Flight mass spectrometer at the TITAN-TRIUMF facility was built to determine atomic masses. This device is the preferred tool to work with exotic nuclides due to its ability to resolve the species of interest from contamination and short measurement cycle times, enabling mass measurements of isotopes with millisecond half-lives. With a relative precision of the order 10, we demonstrate why the TITAN MR-TOF MS is the tool of choice for precision mass surveys for nuclear structure and astrophysics. The capabilities of the device are showcased in this work, including new mass measurements of short-lived tin isotopes (Sn) approaching the proton dripline as well as Zr, Y, and Y. The last three illustrate how the broadband surveys of MR-TOF MS reach beyond the species of immediate interest