Search

The precision measurement of the tritium $\beta$-decay spectrum performed by the KATRIN experiment provides a unique way to search for general neutrino interactions (GNI). All theoretical allowed GNI terms involving neutrinos are incorporated into a low-energy effective field theory, and can be identified by specific signatures in the measured tritium $\beta$-spectrum. In this paper an effective description of the impact of GNI on the $\beta$-spectrum is formulated and the first constraints on the effective GNI parameters are derived based on the 4 million electrons collected in the second measurement campaign of KATRIN in 2019. In addition, constraints on selected types of interactions are investigated, thereby exploring the potential of KATRIN to search for more specific new physics cases, including a right-handed W boson, a charged Higgs or leptoquarks.

We present a proposal for a future light dark matter search experiment at the Electron Stretcher Accelerator ELSA in Bonn: Lohengrin. It employs the fixed-target missing momentum based technique for searching for dark-sector particles. The Lohengrin experiment uses a high intensity electron beam that is shot onto a thin target to produce mainly SM bremsstrahlung and - in rare occasions - possibly new particles coupling feebly to the electron. A well motivated candidate for such a new particle is the dark photon, a new massive gauge boson arising from a new gauge interaction in a dark sector and mixing kinetically with the standard model photon. The Lohengrin experiment is estimated to reach sensitivity to couplings small enough to explain the relic abundance of dark matter in various models for dark photon masses between approximately 1 MeV and approximately 100 MeV.

The projected sensitivity of the effective electron neutrino-mass measurement with the KATRIN experiment is below 0.3 eV (90 % CL) after five years of data acquisition. The sensitivity is affected by the increased rate of the background electrons from KATRIN's main spectrometer. A special shifted-analysing-plane (SAP) configuration was developed to reduce this background by a factor of two. The complex layout of electromagnetic fields in the SAP configuration requires a robust method of estimating these fields. We present in this paper a dedicated calibration measurement of the fields using conversion electrons of gaseous $^\mathrm{83m}$Kr, which enables the neutrino-mass measurements in the SAP configuration., Comment: 19 pages, 11 figures

The advancements in smart sensors for Industry 4.0 offer ample opportunities for low-powered predictive maintenance and condition monitoring. However, traditional approaches in this field rely on processing in the cloud, which incurs high costs in energy and storage. This paper investigates the potential of neural networks for low-power on-device computation of vibration sensor data for predictive maintenance. We review the literature on Spiking Neural Networks (SNNs) and Artificial Neuronal Networks (ANNs) for vibration-based predictive maintenance by analyzing datasets, data preprocessing, network architectures, and hardware implementations. Our findings suggest that no satisfactory standard benchmark dataset exists for evaluating neural networks in predictive maintenance tasks. Furthermore frequency domain transformations are commonly employed for preprocessing. SNNs mainly use shallow feed forward architectures, whereas ANNs explore a wider range of models and deeper networks. Finally, we highlight the need for future research on hardware implementations of neural networks for low-power predictive maintenance applications and the development of a standardized benchmark dataset., Comment: The final version will be published at the ECML-PKDD 2024 joint post-workshop proceeding in Springer Communications in Computer and Information Science

Surveys in the Milky Way and Large Magellanic Cloud revealed that the majority of massive stars will interact with companions during their lives. However, knowledge of the binary properties of massive stars at low metallicity, which approaches the conditions of the Early Universe, remains sparse. We present the Binarity at LOw Metallicity (BLOeM) campaign - an ESO large programme designed to obtain 25 epochs of spectroscopy for 929 massive stars in the SMC - the lowest metallicity conditions in which multiplicity is probed to date (Z = 0.2 Zsun). BLOeM will provide (i) the binary fraction, (ii) the orbital configurations of systems with periods P < 3 yr, (iii) dormant OB+BH binaries, and (iv) a legacy database of physical parameters of massive stars at low metallicity. The stars are observed with the LR02 setup of the giraffe instrument of the Very Large Telescope (3960-4570A, resolving power R=6200; typical signal-to-noise ratio S/N=70-100). This paper utilises the first 9 epochs obtained over a three-month time. We describe the survey and data reduction, perform a spectral classification of the stacked spectra, and construct a Hertzsprung-Russell diagram of the sample via spectral-type and photometric calibrations. The sample covers spectral types from O4 to F5, spanning the effective temperature and luminosity ranges 6.5

The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium $\beta$-decay close to the kinematic endpoint. Based on the first five neutrino-mass measurement campaigns, we derive a best-fit value of $m_\nu^{2} = {-0.14^{+0.13}_{-0.15}}~\mathrm{eV^2}$, resulting in an upper limit of $m_\nu < {0.45}~\mathrm{eV}$ at 90 % confidence level. With six times the statistics of previous data sets, amounting to 36 million electrons collected in 259 measurement days, a substantial reduction of the background level and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two., Comment: 61 pages, 20 figures, 2 tables

Collider processes with identified hadrons in the final state are widely studied in view of determining details of the proton structure and of understanding hadronization. Their theory description requires the introduction of fragmentation functions, which parametrise the transition of a produced parton into the identified hadron. To compute higher-order perturbative corrections to these processes requires a subtraction method for infrared singular configurations. We extend the antenna subtraction method to hadron fragmentation processes in hadronic collisions up to next-to-next-to-leading order (NNLO) in QCD by computing the required fragmentation antenna functions in initial-final kinematics. The integrated antenna functions retain their dependence on the momentum fractions of the incoming and fragmenting partons., Comment: 55 pages, 27 tables; v2: as published

In order to predict the black hole mass distributions at high redshift, we need to understand whether very massive single stars ($M>40$ M$_\odot$) at low metallicity $Z$ lose their hydrogen-rich envelopes, like their metal-rich counterparts, or whether a binary companion is required to achieve this. To test this, we undertake a deep spectroscopic search for binary companions of the seven apparently single Wolf-Rayet (WR) stars in the Small Magellanic Cloud (SMC; $Z \simeq 1/5 Z_\odot$). For each of them, we acquired six high-quality VLT-UVES spectra spread over 1.5 years. By using the narrow N V lines in these spectra, we monitor radial velocity (RV) variations to search for binary motion. We find low RV variations between 6 and 23 km/s for the seven WR stars, with a median standard deviation of $5$ km/s. Our Monte Carlo simulations imply probabilities below ~5% for any of our target WR stars to have a binary companion more massive than ~5 M$_\odot$ at orbital periods of less than a year. We estimate that the probability that all our target WR stars have companions with orbital periods shorter than 10 yr is below ~10$^{-5}$, and argue that the observed modest RV variations may originate from intrinsic atmosphere or wind variability. Our findings imply that metal-poor massive stars born with $M \gtrsim 40$ M$_\odot$ can lose most of their hydrogen-rich envelopes via stellar winds or eruptive mass loss, which strongly constrains their initial mass - black hole mass relation. We also identify two of our seven target stars (SMC AB1 and SMC AB11) as runaway stars with a peculiar radial velocity of ~80 km/s. Moreover, with all five previously detected WR binaries in the SMC exhibiting orbital periods of below 20 d, a puzzling absence of intermediate-to-long-period WR binaries has emerged, with strong implications for the outcome of massive binary interaction at low metallicity., Comment: Accepted for publication in Astronomy & Astrophysics

We give a $K$-theoretic and geometric interpretation for a generalized weighted Ehrhart theory of a full-dimensional lattice polytope $P$, depending on a given homogeneous polynomial function $\varphi$ on $P$, and with Laurent polynomial weights $f_Q(y)\in \mathbb{Z}[y^{\pm 1}]$ associated to the faces $Q \preceq P$ of the polytope. For this purpose, we calculate equivariant $K$-theoretic Hodge-Chern classes of an equivariant mixed Hodge module $\mathcal{M}$ on the toric variety $X_P$ associated to $P$ (defined via an equivariant embedding of $X_P$ into an ambient smooth variety). For any integer $\ell$, we introduce a corresponding equivariant Hodge $\chi_y$-polynomial $\chi_y(X_P, \ell D_P; [\mathcal{M}])$, with $D_P$ the corresponding ample Cartier divisor on $X_P$ (defined by the facet presentation of $P$). Motivic properties of the Hodge-Chern classes are used to express this equivariant Hodge polynomial in terms of weighted character sums fitting with a generalized weighted Ehrhart theory. The equivariant Hodge polynomials are shown to satisfy a reciprocity and purity formula fitting with the duality for equivariant mixed Hodge modules, and implying the corresponding properties for the generalized weighted Ehrhart polynomials. In the special case of the equivariant intersection cohomology mixed Hodge module, with the weight function corresponding to Stanley's $g$-function of the polar polytope of $P$, we recover in geometric terms a recent combinatorial formula of Beck--Gunnells--Materov., Comment: comments are welcome! arXiv admin note: text overlap with arXiv:2403.17747

Focusing is a known technique for reducing the number of proofs while preserving derivability. Skolemisation is another technique designed to improve proof search, which reduces the number of back-tracking steps by representing dependencies on the term level and instantiate witness terms during unification at the axioms or fail with an occurs-check otherwise. Skolemisation for classical logic is well understood, but a practical skolemisation procedure for focused intuitionistic linear logic has been elusive so far. In this paper we present a focused variant of first-order intuitionistic linear logic together with a sound and complete skolemisation procedure., Comment: to appear at IJCAR 2024

The majority of massive stars reside in binary systems, which are expected to experience mass transfer during their evolution. However, so far the conditions under which mass transfer leads to a common envelope, and thus possibly to a merging of both stars, are not well understood. Main uncertainties arise from the possible swelling of the mass gainer, and from angular momentum loss from the binary system, during non-conservative mass transfer. We have computed a dense grid of detailed models of stars accreting mass at constant rates, to determine their radius increase due to their thermal disequilibrium. While we find that models with faster than thermal timescale accretion generally expand, this expansion remains quite limited in the intermediate mass regime even for accretion rates which exceed the thermal timescale accretion rate by a factor of 100. Our models of massive accretion stars expand to extreme radii under those conditions. When the accretion rate exceed the Eddington accretion rate, our models expand dynamically. We have derived analytical fits to the radius evolution of our models and a prescription for the borderline between stable mass transfer and mergers for arbitrary accretion efficiencies. We then apply our results to grids of binary models adopting various constant mass transfer efficiencies and angular momentum budgets. We find that the former parameter has the stronger effect on the outcome of the Roche lobe overflow. Our results are consistent with detailed binary evolution models, and often lead to a smaller initial parameter space for stable mass transfer than other recipes in the literature. We use this method to investigate the origin of the Wolf-Rayet stars with O star companions in the Small Magellanic Cloud, and find that the efficiency of the mass transfer process which lead to the formation of the Wolf-Rayet star was likely below 50%., Comment: 19 pages

Massive binary evolution models are needed to predict massive star populations in star forming galaxies, the supernova diversity, and the number and properties of gravitational wave sources. Such models are often computed using so called rapid binary evolution codes, which approximate the evolution of the binary components based on detailed single star models. However, about one third of the interacting massive binary stars undergo mass transfer during core hydrogen burning (Case A mass transfer), whose outcome is difficult to derive from single star models. Here, we use a large grid of detailed binary evolution models for primaries in the initial mass range 10 to 40 Solar masses of LMC and SMC composition, to derive analytic fits for the key quantities needed in rapid binary evolution codes, i.e., the duration of core hydrogen burning, and the resulting donor star mass. Systems with shorter orbital periods produce up to 50% lighter stripped donors and have a up to 30% larger lifetime than wider systems. We find that both quantities depend strongly on the initial binary orbital period, but that the initial mass ratio and the mass transfer efficiency of the binary have little impact on the outcome. Our results are easily parameterisable and can be used to capture the effects of Case A mass transfer more accurately in rapid binary evolution codes., Comment: 10 pages

We survey recent developments in the study of torus equivariant motivic Chern and Hirzebruch characteristic classes of projective toric varieties, with applications to calculating equivariant Hirzebruch genera of torus-invariant Cartier divisors in terms of torus characters, as well as to general Euler-Maclaurin type formulae for full-dimensional simple lattice polytopes. We present recent results by the authors, emphasizing the main ideas and some key examples. This includes global formulae for equivariant Hirzebruch classes in the simplicial context proved by localization at the torus fixed points, a weighted versions of a classical formula of Brion, as well as of the Molien formula of Brion-Vergne. Our Euler-Maclaurin type formulae provide generalizations to arbitrary coherent sheaf coefficients of the Euler-Maclaurin formulae of Cappell-Shaneson, Brion-Vergne, Guillemin, etc., via the equivariant Hirzebruch-Riemann-Roch formalism. Our approach, based on motivic characteristic classes, allows us, e.g., to obtain such Euler-Maclaurin formulae also for (the interior of) a face. We obtain such results also in the weighted context, and for Minkovski summands of the given full-dimensional lattice polytope., Comment: survey paper overviewing recent results by the authors from arXiv:2303.16785, emphasizing the main ideas and some key examples

We give a cohomological and geometrical interpretation for the weighted Ehrhart theory of a full-dimensional lattice polytope $P$, with Laurent polynomial weights of geometric origin. For this purpose, we calculate the motivic Chern and Hirzebruch characteristic classes of a mixed Hodge module complex $\mathcal{M}$ whose underlying cohomology sheaves are constant on the $\mathbb{T}$-orbits of the toric variety $X_P$ associated to $P$. Besides motivic coefficients, this also applies to the intersection cohomology Hodge module. We introduce a corresponding generalized Hodge $\chi_y$-polynomial of the ample divisor $D_P$ on $X_P$. Motivic properties of these characteristic classes are used to express this Hodge polynomial in terms of a very general weighed lattice point counting and the corresponding weighted Ehrhart theory. We introduce, for such a mixed Hodge modules complex $\mathcal{M}$ on $X$, an Ehrhart polynomial $E_{P,\mathcal{M}}$ generalizing the Hodge polynomial of $\mathcal{M}$ and satisfying a reciprocity formula and a purity formula fitting with the duality for mixed Hodge modules. This Ehrhart polynomial and its properties depend only on a Laurent polynomial weight function on the faces $Q$ of $P$. In the special case of the intersection cohomology mixed Hodge module, the weight function corresponds to Stanley's $g$-function of the polar polytope of $P$, hence it depends only on the combinatorics of $P$. In particular, we obtain a combinatorial formula for the intersection cohomology signature., Comment: comments are welcome! v2: corrected several typos, added one reference

Mobile robots are being used on a large scale in various crowded situations and become part of our society. The socially acceptable navigation behavior of a mobile robot with individual human consideration is an essential requirement for scalable applications and human acceptance. Deep Reinforcement Learning (DRL) approaches are recently used to learn a robot's navigation policy and to model the complex interactions between robots and humans. We propose to divide existing DRL-based navigation approaches based on the robot's exhibited social behavior and distinguish between social collision avoidance with a lack of social behavior and socially aware approaches with explicit predefined social behavior. In addition, we propose a novel socially integrated navigation approach where the robot's social behavior is adaptive and emerges from the interaction with humans. The formulation of our approach is derived from a sociological definition, which states that social acting is oriented toward the acting of others. The DRL policy is trained in an environment where other agents interact socially integrated and reward the robot's behavior individually. The simulation results indicate that the proposed socially integrated navigation approach outperforms a socially aware approach in terms of ego navigation performance while significantly reducing the negative impact on all agents within the environment., Comment: Accepted at 2024 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

We illustrate how purpose-specific, graphical modeling enables application experts with different levels of expertise to collaboratively design and then produce complex applications using their individual, purpose-specific modeling language. Our illustration includes seven graphical Integrated Modeling Environments (IMEs) that support full code generation, as well as four browser-based applications that were modeled and then fully automatically generated and produced using DIME, our most complex graphical IME. While the seven IMEs were chosen to illustrate the types of languages we support with our Language-Driven Engineering (LDE) approach, the four DIME products were chosen to give an impression of the power of our LDE-generated IMEs. In fact, Equinocs, Springer Nature's future editorial system for proceedings, is also being fully automatically generated and then deployed at their Dordrecht site using a deployment pipeline generated with Rig, one of the IMEs presented. Our technology is open source and the products presented are currently in use., Comment: 43 pages, 30 figures

Robust and performant controllers are essential for industrial applications. However, deriving controller parameters for complex and nonlinear systems is challenging and time-consuming. To facilitate automatic controller parametrization, this work presents a novel approach using deep reinforcement learning (DRL) with N-dimensional B-spline geometries (BSGs). We focus on the control of parameter-variant systems, a class of systems with complex behavior which depends on the operating conditions. For this system class, gain-scheduling control structures are widely used in applications across industries due to well-known design principles. Facilitating the expensive controller parametrization task regarding these control structures, we deploy an DRL agent. Based on control system observations, the agent autonomously decides how to adapt the controller parameters. We make the adaptation process more efficient by introducing BSGs to map the controller parameters which may depend on numerous operating conditions. To preprocess time-series data and extract a fixed-length feature vector, we use a long short-term memory (LSTM) neural networks. Furthermore, this work contributes actor regularizations that are relevant to real-world environments which differ from training. Accordingly, we apply dropout layer normalization to the actor and critic networks of the truncated quantile critic (TQC) algorithm. To show our approach's working principle and effectiveness, we train and evaluate the DRL agent on the parametrization task of an industrial control structure with parameter lookup tables., Comment: 7 pages, 7 figures, accepted at the 2023 IEEE International Conference on Systems, Man, and Cybernetics (SMC), Honolulu, HI, USA

Brasselet, the second author and Yokura introduced Hodge-theoretic Hirzebruch-type characteristic classes $IT_{1, \ast}$, and conjectured that they are equal to the Goresky-MacPherson $L$-classes for pure-dimensional compact complex algebraic varieties. In this paper, we show that the framework of Gysin coherent characteristic classes of singular complex algebraic varieties developed by the first and third author in previous work applies to the characteristic classes $IT_{1, \ast}$. In doing so, we prove the ambient version of the above conjecture for a certain class of subvarieties in a Grassmannian, including all Schubert subvarieties. Since the homology of Schubert subvarieties injects into the homology of the ambient Grassmannian, this implies the conjecture for all Schubert varieties in a Grassmannian. We also study other algebraic characteristic classes such as Chern classes and Todd classes (or their variants for the intersection cohomology sheaves) within the framework of Gysin coherent characteristic classes.

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective mass of the electron antineutrino via a high-precision measurement of the tritium beta-decay spectrum in its end-point region. The target neutrino-mass sensitivity of 0.2 eV / c^2 at 90% C.L. can only be achieved in the case of high statistics and a good control of the systematic uncertainties. One key systematic effect originates from the calculation of the molecular final states of T_2 beta decay. In the first neutrino-mass analyses of KATRIN the contribution of the uncertainty of the molecular final-states distribution (FSD) was estimated via a conservative phenomenological approach to be 0.02 eV^2 / c^4. In this paper a new procedure is presented for estimating the FSD-related uncertainties by considering the details of the final-states calculation, i.e. the uncertainties of constants, parameters, and functions used in the calculation as well as its convergence itself as a function of the basis-set size used in expanding the molecular wave functions. The calculated uncertainties are directly propagated into the experimental observable, the squared neutrino mass m_nu^2. With the new procedure the FSD-related uncertainty is constrained to 0.0013 eV^2 / c^4, for the experimental conditions of the first KATRIN measurement campaign.

Here we report on the analysis of a metallic Late Neolithic copper axe by means of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The axe was found at Eskilstorp, south-west Scania during archaeological excavations in autumn of 2015. It showed a hint of silver en-richment on the surface which is unusual for Late Neolithic axes from Pile type hoard. To identify the origin of the silver content, we extracted a thin lamella of the axe interior using Focused Ion Beam (FIB) technology to reach the internal structure to keep the process extremely minimally invasive. The results revealed the presence of porous external layer of copper oxide enriched with silver particles. It is shown with the corrosion test performed on copper-silver experimental replica that the silver en-richment is attributed to the selective dissolution of copper metal as a resut of corrosion process on the axe. The corrosion experiment is performed in the presence of an organic electrolyte such as Hemic Acid (HA) which replicates soil and natural water environment. In the scope of this research work, we found a strong evidence that the silver on the surface of the axe was not decrative layer and instead remained on the surface due to its more noble character while copper leached out into the soil due to corrosion.

In R-parity-violating (RPV) supersymmetric models, light neutralinos with masses from the GeV-scale down to even zero are still allowed by all laboratory constraints. They are further consistent with dark matter observations, as they decay via RPV couplings. These RPV couplings are in general constrained to be small. Hence, such light neutralinos, if produced, e.g., at a beam-dump or collider experiment, appear as displaced vertices or missing energy at the detector level. The same signatures have been extensively searched for at various experiments in the theoretical context of sterile neutrinos which mix with active neutrinos. In this work, we recast the sensitivity of both past and present experiments to sterile neutrinos to obtain new bounds on RPV couplings associated with a light neutralino. We find experiments such as T2K, BEBC, FASER, DUNE, and MoEDAL-MAPP can improve the current bounds on RPV couplings by up to $3-4$ orders of magnitude in several benchmark scenarios., Comment: 33 pages + references, 11 figures, and 8 tables, accepted for publication in JHEP

Session types are types for specifying the protocols that communicating processes must follow in a concurrent system. When composing two or more well-typed processes, a session typing system must check whether such processes are multiparty compatible, a property that guarantees that all sent messages are eventually received and no deadlock ever occurs. Previous work has shown that duality and the more general notion of coherence are sufficient syntactic conditions for guaranteeing the multiparty compatibility property. In this paper, following a propositions-as-types fashion which relates session types to linear logic, we generalise coherence to forwarders. Forwarders are processes that act as middleware by forwarding messages according to a given protocol. Our main result shows that forwarders not only generalise coherence, but fully capture all well-typed multiparty compatible processes., Comment: arXiv admin note: substantial text overlap with arXiv:2112.07636

In this paper we give a first study of perfect copositive $n \times n$ matrices. They can be used to find rational certificates for completely positive matrices. We describe similarities and differences to classical perfect, positive definite matrices. Most of the differences occur only for $n \geq 3$, where we find for instance lower rank and indefinite perfect matrices. Nevertheless, we find for all $n$ that for every classical perfect matrix there is an arithmetically equivalent one which is also perfect copositive. Furthermore we study the neighborhood graph and polyhedral structure of perfect copositive matrices. As an application we obtain a new characterization of the cone of completely positive matrices: It is equal to the set of nonnegative matrices having a nonnegative inner product with all perfect copositive matrices., Comment: 20 pages, 1 figure

We consider equivariant versions of the motivic Chern and Hirzebruch characteristic classes of a quasi-projective toric variety, and extend many known results from non-equivariant to the equivariant setting. The corresponding generalized equivariant Hirzebruch genus of a torus-invariant Cartier divisor is also calculated. Further global formulae for equivariant Hirzebruch classes are obtained in the simplicial context by using the Cox construction and the equivariant Lefschetz-Riemann-Roch theorem. Alternative proofs of all these results are given via localization at the torus fixed points in equivariant $K$- and homology theories. In localized equivariant $K$-theory, we prove a weighted version of a classical formula of Brion for a full-dimensional lattice polytope. We also generalize to the context of motivic Chern classes the Molien formula of Brion-Vergne. Similarly, we compute the localized Hirzebruch class, extending results of Brylinski-Zhang for the localized Todd class. We also elaborate on the relation between the equivariant toric geometry via the equivariant Hirzebruch-Riemann-Roch and Euler-Maclaurin type formulae for full-dimensional simple lattice polytopes. Our results provide generalizations to arbitrary coherent sheaf coefficients, and algebraic geometric proofs of (weighted versions of) the Euler-Maclaurin formulae of Cappell-Shaneson, Brion-Vergne, Guillemin, etc., via the equivariant Hirzebruch-Riemann-Roch formalism. Our approach, based on motivic characteristic classes, allows us to obtain such Euler-Maclaurin formulae also for (the interior of) a face, or for the polytope with several facets removed. We also prove such results in the weighted context, and for Minkovski summands of the given full-dimensional lattice polytope. Some of these results are extended to local Euler-Maclaurin formulas for the tangent cones at the vertices of the given lattice polytope., Comment: 96 pages, comments are very welcome; minor additions in v2

In this paper we prove a new generic vanishing theorem for $X$ a complete homogeneous variety with respect to an action of a connected algebraic group. Let $A, B_0\subset X$ be locally closed affine subvarieties, and assume that $B_0$ is smooth and pure dimensional. Let $\mathcal{P}$ be a perverse sheaf on $A$ and let $B=g B_0$ be a generic translate of $B_0$. Then our theorem implies $(-1)^{\operatorname{codim} B}\chi(A\cap B, \mathcal{P}|_{A\cap B})\geq 0$. As an application, we prove in full generality a positivity conjecture about the signed Euler characteristic of generic triple intersections of Schubert cells. Such Euler characteristics are known to be the structure constants for the multiplication of the Segre-Schwartz-MacPherson classes of these Schubert cells., Comment: 11 pages, comments welcome

For a certain class of solutions of the cubic nonlinear Sch\"odinger equation we prove non-existence in the generic case. In the nongeneric case we present a two-parameter set of solutions, bounded or unbounded, depending on corresponding constraints., Comment: 14 pages, 5 figures

The equivariant motivic Chern class of a Schubert cell in a `complete' flag manifold $X=G/B$ is an element in the equivariant K theory ring of $X$ to which one adjoins a formal parameter $y$. In this paper we prove several `folklore results' about the motivic Chern classes, including finding specializations at $y=-1$ and $y=0$; the coefficient of the top power of $y$; how to obtain Chern-Schwartz-MacPherson (CSM) classes as leading terms of motivic classes; divisibility properties of the Schubert expansion of motivic Chern classes. We collect several conjectures about the positivity, unimodality, and log concavity of CSM and motivic Chern classes of Schubert cells, including a conjectural positivity of structure constants of the multiplication of Poincar\'e duals of CSM classes. In addition, we prove a `star duality' for the motivic Chern classes. We utilize the motivic Chern transformation to define two equivariant variants of the Hirzebruch transformation, which appear naturally in the Grothendieck-Hirzebruch-Riemann-Roch formalism. We utilize the Demazure-Lusztig recursions from the motivic Chern class theory to find similar recursions giving the Hirzebruch classes of Schubert cells, their Poincar{\'e} duals, and their Segre versions. We explain the functoriality properties needed to extend the results to `partial' flag manifolds $G/P$., Comment: 46 pages

We describe a class of combinatorial design problems which typically occur in professional sailing league competitions. We discuss connections to resolvable block designs and equitable coverings and to scheduling problems in operations research. We in particular give suitable boolean quadratic and integer linear optimization problem formulations, as well as further heuristics and restrictions, that can be used to solve sailing league problems in practice. We apply those techniques to three case studies obtained from real sailing leagues and compare the results with previously used tournament plans., Comment: 22 pages, improved exposition, added additional references

Historically, Kennard was the first to choose the standard deviation as a quantitative measure of uncertainty, and neither he nor Heisenberg explicitly explained why this choice should be appropriate from the experimental physical point of view. If a particle is prepared by a single slit of spatial width $\Delta x$, it has been shown that a finite standard deviation $\sigma_p<\infty$ can only be ensured if the wave-function is zero at the edge of $\Delta x$, otherwise it does not exist [8]. Under this circumstances the corresponding sharp inequality is $\sigma_p \Delta x\geq \pi\hbar$. This bound will be reconsidered from the mathematical point of view in terms of a variational problem in Hilbert space and will furthermore be tested in a 4f-single slit diffraction experiment of a laser beam. Our results will be compared with a laser-experiment recently given by Fern\'andez-Guasti (2022) [9]., Comment: 7 pages, 4 figures

We probe how common extremely rapid rotation is among massive stars in the early universe by measuring the OBe star fraction in nearby metal-poor dwarf galaxies. We apply a new method that uses broad-band photometry to measure the galaxy-wide OBe star fractions in the Magellanic Clouds and three more distant, more metal-poor dwarf galaxies. We find OBe star fractions of ~20% in the Large Magellanic Cloud (0.5 Z_Solar), and ~30% in the Small Magellanic Cloud (0.2 Z_Solar) as well as in the so-far unexplored metallicity range from 0.1 Z_solar to 0.2 Z_solar occupied by the other three dwarf galaxies. Our results imply that extremely rapid rotation is common among massive stars in metal-poor environments such as the early universe., Comment: Conference proceedings for a talk in IAU Symposium 361: Massive Stars Near and Far, Ballyconnell, Ireland, 9-13 May 2022

The Early Universe, together with many nearby dwarf galaxies, is deficient in heavy elements. The evolution of massive stars in such environments is thought to be affected by rotation. Extreme rotators amongst them tend to form decretion disks and manifest themselves as OBe stars. We use a combination of U B, GAIA, Spitzer, and Hubble Space Telescope photometry to identify the complete populations of massive OBe stars - one hundred to thousands in number - in five nearby dwarf galaxies. This allows us to derive the galaxy-wide fractions of main sequence stars that are OBe stars (f_OBe), and how it depends on absolute magnitude, mass, and metallicity (Z). We find f_OBe = 0.22 in the Large Magellanic Cloud (0.5 Z_Sun), increasing to f_OBe = 0.31 in the Small Magellanic Cloud (0.2 Z_Sun). In the so far unexplored metallicity regime below 0.2 Z_Sun, in Holmberg I, Holmberg II, and Sextans A, we also obtain high OBe star fractions of 0.27, 0.27, and 0.27, respectively. These high OBe star fractions, and the strong contribution in the stellar mass range which dominates the production of supernovae, shed new light on the formation channel of OBe stars, as well as on the preference of long-duration gamma-ray bursts and superluminous supernovae to occur in metal-poor galaxies., Comment: 19 pages, 23 figures - accepted for publication in Astronomy & Astrophysics

In order to predict the spins of stellar remnants we need to understand the evolution of the internal rotation of stars, and to identify at which stage the rotation of the contracting cores of evolved stars decouples from their expanding envelopes. The donor stars of mass transferring binaries lose almost their entire envelope and may thus offer a direct view on their core rotation. After the mass transfer event they contract and fade rapidly, although they are well observable when caught in the short-lived B-star phase. The B-type primary of the galactic binary system LB-1, which was originally suggested to contain a massive black hole, is nicely explained as a stripped star accompanied by a fainter Be star. The narrow absorption lines in the primary's spectrum signify extremely slow rotation, atypical of B-type main-sequence stars. Here we investigate the evolution of mass donors in generic grids of detailed binary evolution models, where both stars include differential rotation, internal angular momentum transport, and spin-orbit coupling. Whereas the mass gainers are typically spun-up during the mass transfer, we find that the spins of the stripped donor models depend sensitively on the employed mechanism for internal angular momentum transport. Purely hydrodynamic transport cannot explain the observed slow rotation, while models including magnetic angular momentum transport are able to reproduce the observed rotation of LB-1 and similar stars, independent of the initial rotation rate. In such models the spin of the white dwarfs that emerge at the end of the evolution is independent of the mass stripping. We find evidence that the mass transfer in LB-1 was moderately non-conservative., Comment: 18 pages, 13 figures. Accepted in Astronomy and Astrophysics

Isolated photon production at hadron colliders proceeds via direct production and fragmentation processes. Theory predictions for the isolated photon and photon-plus-jet cross section often impose idealised photon isolation criteria, eliminating the fragmentation contribution and introducing a systematic uncertainty in the comparison to data. We present NNLO predictions for the photon-plus-jet cross section with the experimental isolation including both, direct and fragmentation contributions. Predictions with two different parton-to-photon fragmentation functions are compared, allowing for an estimation of the uncertainty stemming from the only loosely constrained photon fragmentation functions., Comment: 11 pages, 2 figures, one table, contribution to the proceedings of "Loops and Legs in Quantum Field Theory - LL2022, 25-30 April, 2022, Ettal, Germany"

This article is on the research of Wilhelm von Waldenfels in the mathematical field of quantum (or non-commutative) probability theory. Wilhelm von Waldenfels was one of the pioneers, even one of the founders, of quantum probability. We concentrate on a small part of his scientific work. The aspects of physics are practically not mentioned at all. There is nothing on his results in classical probability on groups (Waldenfels operators). This is an attempt to show how the concepts of non-commutative notions of independence and of L\'evy processes on structures like Hopf algebras developed from the ideas of Wilhelm von Waldenfels., Comment: This article is my contribution to the special volume of IDAQP in memory of Robin L. Hudson and Wilhelm von Waldenfels

Isolated photons at hadron colliders are defined by permitting only a limited amount of hadronic energy inside a fixed-size cone around the candidate photon direction. This isolation criterion admits contributions from collinear photon radiation off QCD partons and from parton-to-photon fragmentation processes. We compute the NNLO QCD corrections to isolated photon and photon-plus-jet production, including these two contributions. Our newly derived results allow us to reproduce the isolation prescription used in the experimental measurements, performing detailed comparisons with data from the LHC experiments. We quantify the impact of different photon isolation prescriptions, including no isolation at all, on photon-plus-jet cross sections and discuss possible measurements of the photon fragmentation functions at hadron colliders., Comment: 42 pages, 19 figures, one table, journal version, four ancillary data files with the NNLO predictions enclosed

In their interesting article (Physical Review A, Vol. 101, 023843 (2020)) Conforti et al. present doubly periodic (elliptic) solutions of the nonlinear Schr\"odinger equation, based on an earlier article by Akhmediev et.al. (Theoretical and Mathematical Physics, Vol. 72, 809 (1987)). We present some notes with respect to correctness, completeness, and representation of the solutions obtained.

We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these models to be further improved and systematic uncertainties to be reduced, directly contributing to future experimental success. Event generators are part of a much larger ecosystem of computational tools. They typically involve a number of unknown model parameters that must be tuned to experimental data, while maintaining the integrity of the underlying physics models. Making both these data, and the analyses with which they have been obtained accessible to future users is an essential aspect of open science and data preservation. It ensures the consistency of physics models across a variety of experiments., Comment: 164 pages, 10 figures, contribution to Snowmass 2021

We present a physics show musical with live physics experiments and live performed songs with live orchestral accompaniment. The musical was first put on stage in German at the Physikalische Institut, University of Bonn, on the 24th of March, 2019. Here we present the original German script as well as an English translation, including a translation of the songs. We also give brief descriptions of all the experiments employed, with photos as well as how we present the experiments. The musical tells the story of a couple, Life and Death, nicknamed Vita and Mortis, who want to buy a planet where they can settle down and raise a family. They arrive at the store Planetamos, run by the manager Luna Callisto and the scientist Jupi Mercury. The latter two present to Vita and Mortis what is required for life on a planet, as well as all of the extra features for sale, to make it that very special place for their family. Through Vita and Mortis the audience learns about the physical requirements for life on a planet orbiting a star. The show involves 14 live physics experiments. The four actors sing 7 songs, which are to well-known tunes with new lyrics, in German. During the show the singers are accompanied by a small live orchestra, consisting of a flute, an oboe, a piano, a violin, a cello, a harp and percussion. The show was developed by the University of Bonn physics students, who have all been very active in the University of Bonn Physics Show (Physikshow der Universitaet Bonn) the past few years. To the best of our knowledge this is the first physics show musical with live experiments and live song and orchestra., Comment: 86 pages, 18 figures

The theoretical description of photon production at particle colliders combines direct photon radiation and fragmentation processes, which can not be separated from each other for definitions of photon isolation used in experimental measurements. The theoretical description of these processes must account for collinear parton-photon configurations, retaining the dependence on the photon momentum fraction, and includes the parton-to-photon fragmentation functions. We extend the antenna subtraction method to include photon fragmentation processes up to next-to-next-to-leading order (NNLO) in QCD. Collinear photon radiation is handled using newly introduced fragmentation antenna functions and associated phase space mappings. We derive the integrated forms of the fragmentation antenna functions and describe their interplay with the mass factorisation of the photon fragmentation functions. The construction principles of antenna subtraction terms up to NNLO for identified photons are outlined, thereby enabling the application of the method to different photon production processes at colliders., Comment: 47 pages, 1 figure, 1 table, two ancillary files with the expressions for the NNLO fragmentation antenna functions enclosed, typos corrected, journal version

Session types define protocols that processes must follow when communicating. The special case of binary session types, i.e. type annotations of protocols between two parties, is known to be in a propositions-as-types correspondence with linear logic. In previous work, we have shown that the generalization to multiparty session types can be expressed either by coherence proofs or by arbiters, processes that act as middleware by forwarding messages according to the given protocol. In this paper, following the propositions-as-types fashion, we generalize arbiters to a logic, which we call forwarder logic, a fragment of classical linear logic still satisfying cut-elimination. Our main result is summarized as follows: forwarders generalize coherence and give an elegant proof-theoretic characterization of multiparty compatibility, a property of concurrent systems guaranteeing that all sent messages are eventually received and no deadlock ever occurs.