Nikola Herceg, Nikola Konjik, A. Naveena Kumara
et al.
Abstract Noncommutative (NC) geometry may open an alternative route to quantum gravity. We study the signatures that quantum structure of spacetime may leave on Dirac quasinormal mode spectrum in the setting defined by a common astrophysical background. For that purpose we examine the influence of spacetime noncommutativity on the Dirac quasinormal modes in modified Reissner–Nordström black hole spacetime. The framework for the latter study is provided by the effective model of NC gravity coupled to fermions introduced in Dimitrijević Ćirić et al. (Eur Phys J C 83:387, 2023). This model describes a classical Dirac field coupled to a modified Reissner–Nordström geometry where the corresponding metric acquires an additional nonvanishing $$r-\varphi $$ r - φ component. As the earlier study shows, this model appears to be equivalent to a model of semiclassical NC gauge theory in which a NC gauge field is coupled to a NC fermion field on the one side and the classical Reissner–Nordström background on the other. We compute the resulting Dirac quasinormal modes and compare them with those of the undeformed Reissner–Nordström spacetime. The results show that spacetime noncommutativity modifies both the oscillation frequencies and damping rates, and induces features in the effective potential and quasinormal mode spectrum reminiscent of a Zeeman-like splitting. Since such geometric modifications are expected to become relevant only near the Planck scale, these effects are more naturally associated with microscopic rather than astrophysical black holes.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract In this paper we study non-factorizable N $$ \mathcal{N} $$ = 1 superamplitudes for massive chiral superstates. We demonstrate how little group scaling and the supersymmetric Ward identities determine the form of non-factorizable massless superamplitudes, then extrapolate to massive superamplitudes by requiring they reduce to the massless form when we send all masses to zero. This technique does not depend on whether or not the superstates are self-conjugate (so that the fermionic components are either Dirac or Majorana) or whether the superamplitude is dressed with a form-factor.
Nuclear and particle physics. Atomic energy. Radioactivity
Christopher Beem, Mario Martone, Matteo Sacchi
et al.
Abstract A well-established organisational principle for Argyres-Douglas-type 𝒩 = 2 superconformal field theories in four dimensions is to characterise such theories by the data defining a(n irregular) Hitchin system on ℂℙ1. The dictionary between Hitchin system data and various features of the corresponding SCFT has been studied extensively, but the overall structure of the resulting space of SCFTs still appears quite complicated. In this work, we systematically delineate a variety of simplifications that arise within this class of constructions due to several large classes of isomorphisms between SCFTs associated with inequivalent Hitchin system data (and their exactly marginal gaugings). We restrict to the most studied class of theories, namely the type A theories without outer automorphism twists.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract With the help of Young tensor technique, we enumerate the complete and independent set of effective operators up to dim-8 for the extension of the standard model with a Goldstone boson by further imposing the Adler’s zero condition in the soft momentum limit. Such basis can be reduced to describe the axion or majoron effective Lagrangian if further (symmetry) constraints are imposed. Then reformulating dark photon as combination of Goldstone boson and transverse gauge boson, the effective operators of the Goldstone boson can be extended to effective chiral Lagrangian description of the dark photon. For the first time we obtain 0 (0), 6 (44), 1 (1), 44 (356), 32 (520) operators in Goldstone effective field theory, and 9 (49), 0 (0), 108 (676), 10 (426), 1904 (40783) operators in dark photon effective field theory at the dimension 4, 5, 6, 7, 8 for one (three) generation of fermions.
Nuclear and particle physics. Atomic energy. Radioactivity
Hamza Abouabid, Abdesslam Arhrib, Hannah Arnold
et al.
Abstract We here report on the progress of the HHH Workshop, that took place in Dubrovnik in July 2023. After the discovery of a particle that complies with the properties of the Higgs boson of the Standard Model, all Standard Model (SM) parameters are in principle determined. However, in order to verify or falsify the model, the full form of the potential has to be determined. This includes the measurement of the triple and quartic scalar couplings. We here report on ongoing progress of measurements for multi-scalar final states, with an emphasis on three SM-like scalar bosons at 125 $$\,\text {Ge}\hspace{-.08em}\text {V}$$ Ge V , but also mentioning other options. We discuss both experimental progress and challenges as well as theoretical studies and models that can enhance such rates with respect to the SM predictions.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract We utilize the lepton number violation signal process p e − → τ + jjj to search for heavy Majorana neutrinos at future proton-electron colliders. The LHeC (FCC-eh) is considered to run with an electron beam energy of 60 GeV, a proton beam energy of 7 (50) TeV and an integrated luminosity of 1 (3) ab −1, and the electron beam is considered to be unpolarized. We apply detector configurations and simulate signal and related standard model background events for both hadronic τ h and leptonic τ ℓ final states, ℓ being a muon. After preselection, multivariate analyses are performed to reject the background. The strategy to reconstruct the heavy neutrino mass is developed and distributions of reconstructed mass are presented. Discovery sensitivities on parameter |V τN |2|V eN |2 /(|V τN |2 + |V eN |2) for the heavy neutrino mass between 10 and 3000 GeV are predicted. At the 2-σ significance, the best discovery sensitivity is ∼ 1.2 × 10 −5 (5.0 × 10 −6) at the LHeC (FCC-eh) when m N ∼ 100 GeV for the hadronic τ h final state. Sensitivities for the leptonic τ ℓ final state are found to be similar to those for the hadronic τ h final state for most of the parameter space investigated. We also derive the limits on mixing parameters from electroweak precision data (EWPD) and DELPHI experiment. Assuming |V τN |2 = |V eN |2 = |V ℓN |2, sensitivity bounds from the LHeC and FCC-eh experiments are found to be stronger than those from EWPD when m N ≲ 900 GeV, and also stronger than those from DELPHI when m N ≳ 70 GeV. Constraints are also interpreted and compared in the |V τN |2 vs. |V eN |2 plane. Compared with current limits from EWPD, DELPHI, and LHC experiments, future pe experiments can probe large additional regions in the parameter space formed by |V τN | 2 and |V eN | 2, and thus significantly enhance the discovery potential for a large portion of the |V τN | 2 vs. |V eN | 2 plane.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract We demonstrate a universal mechanism of a class of instabilities in infrared regions for massless Abelian p-form gauge theories with topological interactions, which we call generalized chiral instabilities. Such instabilities occur in the presence of initial electric fields for the p-form gauge fields. We show that the dynamically generated magnetic fields tend to decrease the initial electric fields and result in configurations with linking numbers, which can be characterized by non-invertible global symmetries. The so-called chiral plasma instability and instabilities of the axion electrodynamics and (4 + 1)-dimensional Maxwell-Chern-Simons theory in electric fields can be described by the generalized chiral instabilities in a unified manner. We also illustrate this mechanism in the (2+1)-dimensional Goldstone-Maxwell model in electric field.
Nuclear and particle physics. Atomic energy. Radioactivity
We measured a set of π ± Σ ∓ , π 0 Σ 0 , and π − Σ 0 invariant mass spectra below and above the ¯ KN mass threshold in K − induced reactions on deuteron. We deduced the S -wave ¯ KN → π Σ and ¯ KN → ¯ KN scattering amplitudes in the isospin 0 channel in the framework of a ¯ KN and π Σ coupled channel. We find that a resonance pole corresponding to Λ (1405) is located at 1417.7 + 6 . 0 − 7 . 4 (fitting errors) + 1 . 1 − 1 . 0 (systematic errors) + [ − 26 . 1 + 6 . 0 − 7 . 9 (fitting errors) + 1 . 7 − 2 . 0 (systematic errors)] i MeV / c 2 , closer to the ¯ KN mass threshold than the value determined by the Particle Data Group.
We perform a thermal unflavored leptogenesis analysis on minimal left-right symmetric models with discrete left-right symmetry identified as generalized parity or charge conjugation. When left-right symmetry is unbroken in the lepton Yukawa sector, the neutrino Dirac coupling matrix is completely determined by neutrino masses and mixing angles, allowing CP violation needed to generate leptogenesis totally resides in the low-energy sector. With two lepton asymmetry generation ways, both type I and mixed type I+II neutrino mass generation mechanisms are considered. After solving the Boltzmann equations numerically, we find that the low-energy CP phases in the lepton mixing matrix can successfully produce the observed baryon asymmetry, and in some cases, the Dirac CP phase can be the only source of CP violation. Finally, we discuss the interplay among low-energy CP phase measurements, leptogenesis, and neutrinoless double beta decay. We show that the viable models for successful leptogenesis can be probed in next-generation neutrinoless double-beta decay experiments.
Nuclear and particle physics. Atomic energy. Radioactivity
Stefania De Curtis, Stefano Moretti, Ryo Nagai
et al.
Abstract We study CP-Violation (CPV) in a Composite 2-Higgs Doublet Model (C2HDM) based on the global symmetry breaking SO(6)/[SO(4) × SO(2)], wherein the strong sector is modeled by a two-site moose structure. Non-trivial complex phases in the interactions involving fermions in both the elementary and strong sectors can induce CPV in the Higgs potential as well as the Yukawa coupling parameters. We compute both of the latter and analyse their dependence upon the aforementioned complex phases. Finally, we discuss physics observables which are distinctive of this model. Even in the simplest case with only one complex phase in the strong sector we can get significant CPV effects.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract Canonical forms of positive geometries play an important role in revealing hidden structures of scattering amplitudes, from amplituhedra to associahedra. In this paper, we introduce “stringy canonical forms”, which provide a natural definition and extension of canonical forms for general polytopes, deformed by a parameter α′. They are defined by real or complex integrals regulated with polynomials with exponents, and are meromorphic functions of the exponents, sharing various properties of string amplitudes. As α′→ 0, they reduce to the usual canonical form of a polytope given by the Minkowski sum of the Newton polytopes of the regulating polynomials, or equivalently the volume of the dual of this polytope, naturally determined by tropical functions. At finite α′, they have simple poles corresponding to the facets of the polytope, with the residue on the pole given by the stringy canonical form of the facet. There is the remarkable connection between the α′→ 0 limit of tree-level string amplitudes, and scattering equations that appear when studying the α′→ ∞ limit. We show that there is a simple conceptual understanding of this phenomenon for any stringy canonical form: the saddle-point equations provide a diffeomorphism from the integration domain to the interior of the polytope, and thus the canonical form can be obtained as a pushforward via summing over saddle points. When the stringy canonical form is applied to the ABHY associahedron in kinematic space, it produces the usual Koba-Nielsen string integral, giving a direct path from particle to string amplitudes without an a priori reference to the string worldsheet. We also discuss a number of other examples, including stringy canonical forms for finite-type cluster algebras (with type A corresponding to usual string amplitudes), and other natural integrals over the positive Grassmannian.
Nuclear and particle physics. Atomic energy. Radioactivity
Rabah Abdul Khalek, Stefano Forte, Thomas Gehrmann
et al.
Abstract We present a systematic investigation of jet production at hadron colliders from a phenomenological point of view, with the dual aim of providing a validation of theoretical calculations and guidance to future determinations of parton distributions (PDFs). We account for all available inclusive jet and dijet production measurements from ATLAS and CMS at 7 and 8 TeV by including them in a global PDF determination, and comparing to theoretical predictions at NNLO QCD supplemented by electroweak (EW) corrections. We assess the compatibility of the PDFs, specifically the gluon, obtained before and after inclusion of the jet data. We compare the single-inclusive jet and dijet observables in terms of perturbative behaviour upon inclusion of QCD and EW corrections, impact on the PDFs, and global fit quality. In the single-inclusive case, we also investigate the role played by different scale choices and the stability of the results upon changes in modelling of the correlated experimental systematics.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract In the R 3 B experiment at FAIR, charged particles with energies up to 600 MeV and forward boosted γ -rays with energies up to 20 MeV need to be detected in scattering experiments. Calorimeters for nuclear physics experiments of this kind, using relativistic radioactive ion beams, require high energy resolution and high efficiency for simultaneous detection of strongly Doppler shifted γ -rays and high-energy charged particles. A calorimeter design that can meet these requirements, using CsI(Tl) scintillators, results in detector elements that may exhibit light output variations with crystal depth, which can limit the attainable resolution. In this paper we present results from a systematic study of 478 detector modules of CALIFA, the R 3 B calorimeter, in order to determine and minimize such variations. To facilitate further systematic studies we also present results for the total absorption length of the scintillation light, using spectrophotometry, light crosstalk between adjacent detector modules, and surface topography of the CsI(Tl) crystals from atomic force microscopy.
Abstract The swampland program of delineating the space of effective field theories consistent with quantum gravity appears similar to the bootstrap program of delineating the space of quantum field theories consistent with conformal symmetry. With this in mind we rewrite the effective field theory of the Large Volume Scenario in AdS space solely in terms of R AdS, in a form suitable for holographic analysis. This rewritten EFT takes a remarkably universal (and previously unnoticed) form, which is uniquely determined in the large-volume limit up to terms suppressed by O $$ \mathcal{O} $$ (1/lnR AdS), with no reference to any of the fluxes, brane or instanton configurations that enter the microphysics of moduli stabilisation. The putative dual 3d CFT will have two low-lying single trace scalars, an even-parity scalar Φ dual to the volume modulus with Δ Φ = 3 2 1 + 19 ≃ 8.038 $$ {\Delta}_{\varPhi }=\frac{3}{2}\left(1+\sqrt{19}\right)\simeq 8.038 $$ and an odd-parity scalar a dual to the volume axion with Δ a = 3. On the AdS side the higher-point interactions are likewise uniquely determined. As the AdS theory is both subject to swampland constraints and holographically related to a CFT, we argue that holography will lead to a ‘bootland’ — a map between swampland constraints on the AdS side and bootstrap constraints on the CFT side. We motivate this with a discussion of swampland quantum gravity constraints on the axion decay constant in the ν → ∞ limit and the 〈ΦΦaa〉 4-point function on the CFT side.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract A family of deformed AdS$$_4$$ 4 –Reissner–Nordström black branes, governed by a free parameter, is derived using the ADM formalism, in the context of the membrane paradigm. Their new event horizons, the Hawking temperature and other aspects are scrutinized. AdS/CFT near-horizon methods are then implemented to compute the shear viscosity-to-entropy ratio for the deformed AdS$$_4$$ 4 –Reissner–Nordström metric. The Killing equation is shown to yield new values for the free parameter and the shear viscosity-to-entropy ratio is used to derive a reliable range for the tidal charge.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract We show that a natural spinor-helicity formalism that can describe massive scattering amplitudes exists in D = 6 dimensions. This is arranged by having helicity spinors carry an index in the Dirac spinor 4 of the massive little group, SO(5) ∼ Sp(4). In the high energy limit, two separate kinds of massless helicity spinors emerge as required for consistency with arXiv:0902.0981, with indices in the two SU(2)’s of the massless little group SO(4). The tensors of 4 lead to particles with arbitrary spin, and using these and demanding consistent factorization, we can fix 3− and 4-point tree amplitudes of arbitrary masses and spins: we provide examples. We discuss the high energy limit of scattering amplitudes and the Higgs mechanism in this language, and make some preliminary observations about massive BCFW recursion.
Nuclear and particle physics. Atomic energy. Radioactivity