| 1. |
- Aartsen, M. G., et al.
(author)
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Computational techniques for the analysis of small signals in high-statistics neutrino oscillation experiments
- 2020
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 977
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Journal article (peer-reviewed)abstract
- The current and upcoming generation of Very Large Volume Neutrino Telescopes - collecting unprecedented quantities of neutrino events - can be used to explore subtle effects in oscillation physics, such as (but not restricted to) the neutrino mass ordering. The sensitivity of an experiment to these effects can be estimated from Monte Carlo simulations. With the high number of events that will be collected, there is a trade-off between the computational expense of running such simulations and the inherent statistical uncertainty in the determined values. In such a scenario, it becomes impractical to produce and use adequately-sized sets of simulated events with traditional methods, such as Monte Carlo weighting. In this work we present a staged approach to the generation of expected distributions of observables in order to overcome these challenges. By combining multiple integration and smoothing techniques which address limited statistics from simulation it arrives at reliable analysis results using modest computational resources.
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| 2. |
- Milstead, David A., et al.
(author)
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Study of the material of the ATLAS inner detector for Run 2 of the LHC
- 2017
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In: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221. ; 12:12
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Journal article (peer-reviewed)abstract
- The ATLAS inner detector comprises three different sub-detectors: the pixel detector, the silicon strip tracker, and the transition-radiation drift-tube tracker. The Insertable B-Layer, a new innermost pixel layer, was installed during the shutdown period in 2014, together with modifications to the layout of the cables and support structures of the existing pixel detector. The material in the inner detector is studied with several methods, using a low-luminosity s=13 TeV pp collision sample corresponding to around 2.0 nb-1 collected in 2015 with the ATLAS experiment at the LHC. In this paper, the material within the innermost barrel region is studied using reconstructed hadronic interaction and photon conversion vertices. For the forward rapidity region, the material is probed by a measurement of the efficiency with which single tracks reconstructed from pixel detector hits alone can be extended with hits on the track in the strip layers. The results of these studies have been taken into account in an improved description of the material in the ATLAS inner detector simulation, resulting in a reduction in the uncertainties associated with the charged-particle reconstruction efficiency determined from simulation. © 2017 CERN.
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| 3. |
- Aad, G., et al.
(author)
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- 2015
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Journal article (peer-reviewed)
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| 4. |
- Di Vecchia, Paolo, et al.
(author)
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Radiation reaction from soft theorems
- 2021
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 818
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Journal article (peer-reviewed)abstract
- Radiation reaction (RR) terms at the third post-Minkowskian (3PM) order have recently been found to be instrumental in restoring smooth continuity between the non-relativistic, relativistic, and ultra-relativistic (including the massless) regimes. Here we propose a new and intriguing connection between RR and soft (bremsstrahlung) theorems which short-circuits the more involved conventional loop computations. Although first noticed in the context of the maximally supersymmetric theory, unitarity and analyticity arguments support the general validity of this 3PM-order connection that we apply, in particular, to Einstein's gravity and to its Jordan-Brans-Dicke extension. In the former case we find full agreement with a recent result by Damour obtained through a very different reasoning.
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| 5. |
- Li, Wenxian, 1989-, et al.
(author)
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HFSZEEMAN95 : A program for computing weak and intermediate magnetic-field- and hyperfine-induced transition rates
- 2020
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In: Computer Physics Communications. - : Elsevier BV. - 0010-4655 .- 1879-2944. ; 253
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Journal article (peer-reviewed)abstract
- Hfszeeman95 is an updated and extended Fortran 95 version of the Hfszeeman program (Andersson and Jönsson, 2008). Given relativistic atomic state functions generated by the Grasp2018 package (Fischer et al., 2019), Hfszeeman95 together with the accompanying Matlab/GNU Octave program Mithit allows for: (1) the computation and plotting of Zeeman energy splittings of magnetic fine- and hyperfine structure substates as functions of the strength of an external magnetic field, (2) the computation of transition rates between different magnetic fine- and hyperfine structure substates in the presence of an external magnetic field and rates of hyperfine-induced transitions in the field free limit, (3) the synthesization of spectral profiles for transitions obtained from (2). With the new features, Hfszeeman95 and the accompanying Matlab/GNU Octave program Mithit are useful for the analysis of observational spectra and to resolve the complex features due to the splitting of the fine and hyperfine levels.
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| 6. |
- Abbasi, R., et al.
(author)
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Limits on Neutrino Emission from GRB 221009A from MeV to PeV Using the IceCube Neutrino Observatory
- 2023
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In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 946:1
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Journal article (peer-reviewed)abstract
- Gamma-ray bursts (GRBs) have long been considered a possible source of high-energy neutrinos. While no correlations have yet been detected between high-energy neutrinos and GRBs, the recent observation of GRB 221009A-the brightest GRB observed by Fermi-GBM to date and the first one to be observed above an energy of 10 TeV-provides a unique opportunity to test for hadronic emission. In this paper, we leverage the wide energy range of the IceCube Neutrino Observatory to search for neutrinos from GRB 221009A. We find no significant deviation from background expectation across event samples ranging from MeV to PeV energies, placing stringent upper limits on the neutrino emission from this source.
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| 7. |
- Blesneag, Stefan, et al.
(author)
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Matter field Kahler metric in heterotic string theory from localisation
- 2018
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In: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :4
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Journal article (peer-reviewed)abstract
- We propose an analytic method to calculate the matter field Kahler metric in heterotic compactifications on smooth Calabi-Yau three-folds with Abelian internal gauge fields. The matter field Kahler metric determines the normalisations of the N = 1 chiral superfields, which enter the computation of the physical Yukawa couplings. We first derive the general formula for this Kahler metric by a dimensional reduction of the relevant supergravity theory and find that its T-moduli dependence can be determined in general. It turns out that, due to large internal gauge flux, the remaining integrals localise around certain points on the compactification manifold and can, hence, be calculated approximately without precise knowledge of the Ricci-flat Calabi-Yau metric. In a final step, we show how this local result can be expressed in terms of the global moduli of the Calabi-Yau manifold. The method is illustrated for the family of Calabi-Yau hypersurfaces embedded in P-1 x P-3 and we obtain an explicit result for the matter field Kahler metric in this case.
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| 8. |
- Hull, Chris, et al.
(author)
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Charges and topology in linearised gravity
- 2024
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In: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; 2024:7
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Journal article (peer-reviewed)abstract
- Covariant conserved 2-form currents for linearised gravity are constructed by contracting the linearised curvature with conformal Killing-Yano tensors. The corresponding conserved charges were originally introduced by Penrose and have recently been interpreted as the generators of generalised symmetries of the graviton. We introduce an off-shell refinement of these charges and find the relation between these improved Penrose charges and the linearised version of the ADM momentum and angular momentum. If the graviton field is globally well-defined on a background Minkowski space then some of the Penrose charges give the momentum and angular momentum while the remainder vanish. We consider the generalisation in which the graviton has Dirac string singularities or is defined locally in patches, in which case the conventional ADM expressions are not invariant under the graviton gauge symmetry in general. We modify them to render them gauge-invariant and show that the Penrose charges give these modified charges plus certain magnetic gravitational charges. We discuss properties of the Penrose charges, generalise to toroidal Kaluza-Klein compactifications and check our results in a number of examples.
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| 9. |
- Yuan, Ya Hua, et al.
(author)
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Angle-resolved photoemission spectroscopy view on the nature of Ce 4f electrons in the antiferromagnetic Kondo lattice CePd5Al2
- 2021
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In: Physical Review B. - : American Physical Society (APS). - 2469-9969 .- 2469-9950. ; 103:12
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Journal article (peer-reviewed)abstract
- We report an angle-resolved photoemission spectroscopy study of the antiferromagnetic Kondo lattice CePd5Al2, focusing on the quasi-two-dimensional k-space nature of its Fermi surface and, tuning photon energy to the Ce 4d-4f on-resonance transition, the hybridization of the Ce 4f state. A strong shoulder feature on the f0 peak was detected, suggesting hybridization between conduction and f bands. On-resonance spectra revealed narrow, yet hybridized quasiparticle bands with sharp peaks and ∼ 9 meV energy dispersion near the Fermi energy EF. The observed dispersive hybridized f band can be well described by a hybridization-band picture based on the periodic Anderson model (PAM). Hence, the 4f electrons in CePd5Al2 display a dual nature, with both localized and itinerant features, but with dominantly localized character.
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| 10. |
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