| 1. |
- Bandyopadhyay, Triparno, et al.
(författare)
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Notes on a Z′
- 2021
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Ingår i: XXIII DAE High Energy Physics Symposium - Select Proceedings. - Singapore : Springer Nature Singapore. - 1867-4941 .- 0930-8989. - 9789813344075 ; 261, s. 175-180
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Konferensbidrag (refereegranskat)abstract
- We reexamine anomaly free U(1) extensions of the standard model in the light of LHC Drell-Yan data, constraints from unitarity, and neutrino-electron scattering to put model-independent bounds in the parameter space populated by MZ′, the Z- Z′ mixing angle (αz ), and the extra U(1) effective gauge coupling (gx′ ). We propose a formalism where any model dependence is absorbed into these three parameters.
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| 2. |
- Ekström, Andreas, 1980
(författare)
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Strong Interactions for Precision Nuclear Physics
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 549-558
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Konferensbidrag (refereegranskat)abstract
- One of the key challenges in ab initio nuclear theory is to understand the emergence of nuclear structure from quantum chromodynamics. I will address this challenge and focus on the statistical aspects of uncertainty quantification and parameter estimation in chiral effective field theory.
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| 3. |
- Hansson, Thors Hans, et al.
(författare)
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Effective field theories for topological states of matter
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer. - 0930-8989 .- 1867-4941. ; 239, s. 1-68
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Tidskriftsartikel (refereegranskat)abstract
- Since the discovery of the quantum Hall effect in the 1980s it has been clear that there exists states of matter characterized by subtle quantum mechanical effects that renders certain properties surprisingly stable against dirt and noise. The theoretical understanding of these topological quantum phases have continued to develop during the last few decades and it has really surged after the discovery of the time-reversal invariant topological insulators. There are many examples of topological phases that have been important for the theoretical understanding of topological states of matter as well as being of great physical relevance. In this chapter we will focus on some examples that we find particularly enlightening and relevant, but we will not make a complete classification. Some of the most important tools for the understanding of topological quantum matter are based on effective field theory methods. We shall employ two different types of effective field theories. The first, which is valid at intermediate length and time-scales, will not capture the physics at microscopic scales. Such theories are the analogs, for topological phases, of the Ginzburg–Landau theories used to describe the usual symmetry breaking non-topological phases. The second type of theories describe the physics on scales where non-topological gapped states would be very boring, namely at distances and times much larger than the correlation length and the time set by the inverse gap. On these scales everything is independent of any distance and the theories will be topological field theories, which do not describe any dynamics in the bulk, but do carry information about topological properties of the excitations, and also about excitations at the boundaries of the system. Finally, we will also study effective response actions. In a strict sense these are not effective theories, since they do not have any dynamical content, but encode the response of the system to external perturbations, typically an electromagnetic field. As we shall see, however, the effective response action for topological states can be used to extract parts of the dynamic theory through a method called functional bosonization.
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| 4. |
- Hernandez, O. J., et al.
(författare)
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A Statistical Analysis of the Nuclear Structure Uncertainties in μD
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 833-837
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Konferensbidrag (refereegranskat)abstract
- The charge radius of the deuteron (D), was recently determined to three times the precision compared with previous measurements using the measured Lamb shift in muonic deuterium ((formula presented)D). However, the (formula presented)D value is 5.6 (formula presented) smaller than the world averaged CODATA-2014 value (Pohl R et al. (2016) Science 353:669 [1]). To shed light on this discrepancy we analyze the uncertainties of the nuclear structure calculations of the Lamb shift in (formula presented)D and conclude that nuclear theory uncertainty is not likely to be the source of the discrepancy.
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| 5. |
- Miliucci, M., et al.
(författare)
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Kaonic Deuterium Precision Measurement at DA Φ NE : The SIDDHARTA-2 Experiment
- 2020
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Ingår i: Recent Progress in Few-Body Physics : Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018 - Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018. - Cham : Springer International Publishing. - 1867-4941 .- 0930-8989. - 9783030323578 - 9783030323561 ; 238, s. 965-969
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Bokkapitel (refereegranskat)abstract
- Light kaonic atoms spectroscopy offers the unique opportunity to perform experiments equivalent to scattering at vanishing relative energies. This allows the determination of the antikaon-nucleus interaction at threshold, without the need of extrapolation to zero energy, as in the case of scattering experiments. In this framework, the SIDDHARTA-2 collaboration aims to perform the first measurement of kaonic deuterium transition to the fundamental level, which is mandatory to extract the isospin dependent antikaon—nucleon scattering lengths. The experiment will be carried out at the DA(formula presented)NE collider of LNF-INFN in 2019–2020.
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| 6. |
- Richter, Steffen, et al.
(författare)
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Spectral and polarization properties of VUV-mirrors for experiments at a HHG beamline
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 241, s. 175-179, s. 175-179
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Konferensbidrag (refereegranskat)abstract
- For polarization-resolved reflection experiments such as ellipsometry, not only is high reflectivity in a wide spectral range required for mirrors but also the quality of their polarization response is important. Furthermore, for VUV ellipsometry, optimal angles of incidence at the sample are between 45° and 60° with respect to the surface normal. In the best case, a setup should even allow variable angles. This requires reflective optics working at non-grazing incidence. In this theoretical study, a selection of potentially relevant materials and mirror designs for broadband use in the VUV is investigated. Based on the available tabulated databases of optical constants, we performed transfer-matrix calculations to obtain reflectance as well as polarization-response spectra in the desired VUV range up to 50 eV. From the variety of materials, we discuss metals that are otherwise commonly used at grazing incidence, Si, SiC, and as representatives for coating layers MgF2, SiO2, and Al2O3. While SiC is most universal, Si with only native oxide layer performs well especially below 25 eV. Aluminum has good properties but oxide layers are very detrimental, as protective coatings are in general.
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| 7. |
- Sahoo, Baidyanath, et al.
(författare)
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Simulation Studies of R2(Δ η, Δ ϕ) and P2(Δ η, Δ ϕ) Correlation Functions in pp Collisions with the PYTHIA and HERWIG Models
- 2022
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Ingår i: Proceedings of the 24th DAE-BRNS High Energy Physics Symposium, 2020. - Singapore : Springer Nature Singapore. - 0930-8989 .- 1867-4941. - 9789811923531 ; 277, s. 349-352
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Konferensbidrag (refereegranskat)abstract
- We presented a study of charge-independent (CI) and charge-dependent (CD) two-particle differential number correlation functions R2 and transverse momentum correlation functions P2 in pp collisions at s=2.76 TeV with the PYTHIA and HERWIG models.Calculations were presented for unidentified hadrons in three pT ranges 0.2 < pT≤ 2.0 GeV/c, 2.0 < pT≤ 5.0 GeV/c, and 5.0 < pT≤ 30.0 GeV/c.PYTHIA and HERWIG both qualitatively reproduce the near-side peak and away-side ridge correlation features reported by experiments.At low pT, both models produce narrower near-side peaks in P2 correlations than in R2 as reported by the ALICE collaboration in p–Pb and Pb–Pb collisions.This suggests that the narrower shape of the P2 near-side peak is largely determined by the pT dependent angular ordering of hadrons produced in jets.Both PYTHIA and HERWIG predict widths that decrease with increasing pT.Widths extracted for P2 correlators are typically significantly narrower than those of the R2 counterparts [1].
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| 8. |
- Sukhareva, O. M., et al.
(författare)
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Validity of Quasi-classical Approaches to True Three-Body Decays
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 283-286
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Konferensbidrag (refereegranskat)abstract
- Within the hyperspherical harmonics (HH) method the three-body problem is reduced to a motion of one effective particle in a “strongly deformed” field, which is described in the coupled-channel formalism. This method is well suited to studies of so-called true three-body decays. The reduction of the hyperspherical equations set to a single-channel approximation provides the basis of standard quasi-classical (QC) expression for width evaluation. We demonstrate that by itself the quasi-classical approach is quite precise in application to typical three-body effective potentials. However, the reduction to a single channel leads to a significant overestimation of the width.
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| 9. |
- Tavani, Francesco, et al.
(författare)
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Insights into the Structure of Reaction Intermediates Through Coupled X-ray Absorption/UV-Vis Spectroscopy
- 2021
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 220, s. 141-154
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Konferensbidrag (refereegranskat)abstract
- In this work, we propose a method for the structural characterization of chemical reaction intermediates. It allows one to analyze time-resolved coupled energy dispersive X-ray absorption spectroscopy (EDXAS) and UV-Vis reaction data through a matricial approach. Concentration profiles for the reaction key species are derived from the UV-Vis data and are used as mathematical constraints to extract their associated X-ray absorption near edge structure (XANES) spectra. The obtained XANES spectra are then quantitatively characterized by full multiple scattering (MS) calculations. We demonstrate the capabilities of this approach by applying it over a series of coupled EDXAS/UV-Vis spectra acquired in the reaction between FeII (tris(2-pyridylmethyl)amine) ([FeII(TPA)(CH3CN)2]2+ ) and H2O2. As a result, structural information for the elusive reaction key intermediate [ FeIII (TPA)(OOH)(X)]2 + is derived and it is suggested that X = CH3CN in opposition to X = H2O.
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| 10. |
- Yang, Zaihong, et al.
(författare)
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Study of Multi-neutron Systems with SAMURAI Spectrometer
- 2020
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Ingår i: Recent Progress in Few-Body Physics, FB22 201. - Cham : Springer International Publishing. - 1867-4941 .- 0930-8989. - 9783030323578 - 9783030323561 ; 238, s. 529-534
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Bokkapitel (refereegranskat)abstract
- The tetraneutron has been drawing the attention of the nuclear physics community for decades, but a firm conclusion on its existence and properties is still far from being reached despite many experimental and theoretical efforts. New measurements have recently been performed at RIBF with the SAMURAI spectrometer by applying complementary reaction probes, which will help to pin down the properties of this four-neutron system.
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