The angle-dependent cusp anomalous dimension governs divergences coming from soft gluon exchanges between heavy particles, such as top quarks. We focus on the matter-dependent contributions and compute the first truly non-planar terms. They appear at four loops and are proportional to a quartic Casimir operator in color space. Specializing our general gauge theory result to U(1), we obtain the full QED four-loop angle-dependent cusp anomalous dimension. While more complicated functions appear at intermediate steps, the analytic answer depends only on multiple polylogarithms with singularities at fourth roots of unity. It can be written in terms of four rational structures, and contains functions of up to maximal transcendental weight seven. Despite this complexity, we find that numerically the answer is tantalizingly close to the appropriately rescaled one-loop formula, over most of the kinematic range. We take several limits of our analytic result, which serves as a check and allows us to obtain new, power-suppressed terms. In the anti-parallel lines limit, which corresponds to production of two massive particles at threshold, we find that the subleading power correction vanishes. Finally, we compute the quartic Casimir contribution for scalars in the loop. Taking into account a supersymmetric decomposition, we derive the first non-planar corrections to the quark anti-quark potential in maximally supersymmetric gauge theory.

The hot and dense core formed in the collapse of a massive star is a powerful source of hypothetical feebly-interacting particles such as sterile neutrinos, dark photons, axion-like particles (ALPs), and others. Radiative decays such as $a\to2\gamma$ deposit this energy in the surrounding material if the mean free path is less than the radius of the progenitor star. For the first time, we use a supernova (SN) population with particularly low explosion energies as the most sensitive calorimeters to constrain this possibility. These SNe are observationally identified as low-luminosity events with low ejecta velocities and low masses of ejected $^{56}$Ni. Their low energies limit the energy deposition from particle decays to less than about 0.1 B, where $1~{\rm B~(bethe)}=10^{51}~{\rm erg}$. For 1-500 MeV-mass ALPs, this generic argument excludes ALP-photon couplings $G_{a\gamma\gamma}$ in the $10^{-10}$-$10^{-8}~{\rm GeV}^{-1}$ range.

We study magnetic conversion of ultra-relativistic axion-like particles (ALPs) into photons in compact-star environments, focusing on the hot, transient conditions of core-collapse supernova (SN) remnants and neutron-star mergers (NSMs). We address previously overlooked uncertainties, particularly the suppression caused by ejected matter near the stellar surface, a region crucial to the conversion process. We derive analytical expressions for the transition rate; they reveal the influence of key parameters and their uncertainties. We update constraints using historical gamma-ray data from SN~1987A and find g_{a\gamma}<5\times10^{-12}~{\rm GeV}^{-1} for $m_a\lesssim10^{-9}$ meV. We also forecast sensitivities for a future Galactic SN and for NSMs, assuming observations with Fermi-LAT or similar gamma-ray instruments. We distinguish ALPs -- defined as coupling only to photons and produced via Primakoff scattering -- from axions, which also couple to nucleons and emerge through nuclear bremsstrahlung. We omit pionic axion production due to its large uncertainties and inconsistencies, though it could contribute comparably to bremsstrahlung under optimistic assumptions. For the compact sources, we adopt time-averaged one-zone models, guided by numerical simulations, to enable clear and reproducible parametric studies.

We study chiral symmetry restoration with increasing temperature and density in gauge theories subject to mutually perpendicular electric and magnetic fields using holography. We determine the chiral symmetry breaking phase structure of the D3/D7 and D3/D5 systems in the temperature-density-electric field directions. A magnetic field may break the chiral symmetry and an additional electric field induces Ohm and Hall currents as well as restoring the chiral symmetry. At zero temperature the D3/D5 system displays a line of holographic BKT phase transitions in the density-electric field plane, while the D3/D7 system shows a mean-field phase transition. At intermediate temperatures, the transitions in the density-electric field plane are of first order at low density, transforming to second order at critical points as density rises. At high temperature the transition is only ever first order.

We analyze the quantum dynamics of a relativistic homogeneous superfluid in a complex scalar field theory. Unlike zero-charge condensates, which undergo quantum evaporation due to internal number-changing processes, we show that $U(1)$ superfluids preserve their internal coherence indefinitely in this theory. In particular, although not Hamiltonian eigenstates, these configurations are stable in the full quantum theory to all orders in perturbation theory. This is demonstrated by explicitly constructing the corresponding quantum state and studying its dynamics. Crucially, maintaining stability requires the quantum state to go beyond a naive coherent-state construction: specific non-Gaussian corrections are essential for having a stationary state. The resulting state is identified as the interacting vacuum of the superfluid fluctuations, which also serves as the ground state of the modified Hamiltonian $\hat{H}-\mu \hat{Q}$, with $\mu$ the full-fledged quantum chemical potential and $\hat{Q}$ the $U(1)$ charge. Finally, we check that the phonon mode remains gapless once one-loop corrections are included, confirming the robustness of the Goldstone theorem beyond the semiclassical regime, even in systems with a spontaneously broken Lorentz symmetry.

The core of a massive star (M > 8 Msun) eventually collapses. This implosion usually triggers a supernova (SN) explosion that ejects most of the stellar envelope and leaves behind a neutron star (NS) with a mass of up to about 2 Msun. Sometimes the explosion fails and a black hole forms instead. The NS radiates its immense binding energy (some 10% of its rest mass or $2-4\times10^{53}$ erg) almost entirely as neutrinos and antineutrinos of all flavors with typical energies of some 10 MeV. This makes core-collapse SNe the most powerful neutrino factories in the Universe. Such a signal was observed once - with limited statistics - from SN 1987A in the Large Magellanic Cloud. Today, however, many large neutrino detectors act as SN observatories and would register a high-statistics signal. A future Galactic SN, though rare (1-3 per century), would produce a wealth of astrophysical and particle-physics information, including possible signatures for new particles. Neutrinos are key to SN dynamics in the framework of the Bethe-Wilson delayed explosion paradigm. After collapse, they are trapped in the core for a few seconds, forming a dense neutrino plasma that can exhibit collective flavor evolution caused by the weak interaction, a subject of intense theoretical research.

We study preheating after hilltop inflation where the inflaton couples to another scalar field, e.g. a right-handed sneutrino, which provides a mechanism for generating the correct initial conditions for inflation and also a decay channel for the inflaton that allows for reheating and non-thermal leptogenesis. In the presence of such a coupling, we find that after the phases of tachyonic preheating and tachyonic oscillations, during which the inflaton field becomes inhomogeneous, there can be a subsequent preheating phase where the fluctuations of the other field get resonantly enhanced, from initial vacuum fluctuations up to amplitudes of the same order (and even larger) as the ones of the inflaton field. This resonant enhancement differs from the usual parametric resonance as the inflaton field is inhomogeneous at the time the enhancement takes place. We study this effect using lattice simulations as well as semi-analytically with a generalized Floquet analysis for inhomogeneous background fields.

We study magnetic conversion of ultra-relativistic axion-like particles (ALPs) into photons in compact-star environments, focusing on the hot, transient conditions of core-collapse supernova (SN) remnants and neutron-star mergers (NSMs). We address previously overlooked uncertainties, particularly the suppression caused by ejected matter near the stellar surface, a region crucial to the conversion process. We derive analytical expressions for the transition rate; they reveal the influence of key parameters and their uncertainties. We update constraints using historical gamma-ray data from SN~1987A and find g_{a\gamma}<5\times10^{-12}~{\rm GeV}^{-1} for $m_a\lesssim10^{-9}$ meV. We also forecast sensitivities for a future Galactic SN and for NSMs, assuming observations with Fermi-LAT or similar gamma-ray instruments. We distinguish ALPs -- defined as coupling only to photons and produced via Primakoff scattering -- from axions, which also couple to nucleons and emerge through nuclear bremsstrahlung. We omit pionic axion production due to its large uncertainties and inconsistencies, though it could contribute comparably to bremsstrahlung under optimistic assumptions. For the compact sources, we adopt time-averaged one-zone models, guided by numerical simulations, to enable clear and reproducible parametric studies.

Predictions for the Higgs masses are a distinctive feature of supersymmetric extensions of the Standard Model, where they play a crucial role in constraining the parameter space. The discovery of a Higgs boson and the remarkably precise measurement of its mass at the LHC have spurred new efforts aimed at improving the accuracy of the theoretical predictions for the Higgs masses in supersymmetric models. The "Precision SUSY Higgs Mass Calculation Initiative" (KUTS) was launched in 2014 to provide a forum for discussions between the different groups involved in these efforts. This report aims to present a comprehensive overview of the current status of Higgs-mass calculations in supersymmetric models, to document the many advances that were achieved in recent years and were discussed during the KUTS meetings, and to outline the prospects for future improvements in these calculations.

We document the three main new features in release 2.0.0 of the HOPPET parton distribution function evolution code, specifically support for N$^3$LO QCD evolution in the variable flavour number scheme, for the determination of hadronic structure functions for massless quarks up to N$^3$LO, and for QED evolution to an accuracy phenomenologically equivalent to NNLO QCD. Additionally we describe a new Python interface, CMake build option, functionality to save a hoppet table as an LHAPDF grid and update our performance benchmarks, including optimisations in interpolating PDF tables.

We present a classification of a large class of type IIA N=1 supersymmetric compactifications to AdS4, based on left-invariant SU(3)-structures on coset spaces. In the absence of sources the parameter spaces of all cosets leading to a solution contain regions corresponding to nearly-Kaehler structure. I.e. all these cosets can be viewed as deformations of nearly-Kaehler manifolds. Allowing for (smeared) six-brane/orientifold sources we obtain more possibilities. In the second part of the paper, we use a simple ansatz, which can be applied to all six-dimensional coset manifolds considered here, to construct explicit thick domain wall solutions separating two AdS4 vacua of different radii. We also consider smooth interpolations between AdS4 x M6 and R^{1,2} x M7, where M6 is a nearly-Kaehler manifold and M7 is the G2-holonomy cone over M6.

We consider thermal strongly-coupled N=2 SYM theory with fundamental matter at finite isospin chemical potential. Using gauge/gravity duality, i.e. a probe of two flavor D7-branes embedded in the AdS black hole background, we find a critical temperature at which the system undergoes a second order phase transition. The critical exponent of this transition is one half and coincides with the result from mean field theory. In the thermodynamically favored phase, a flavor current acquires a vev and breaks an Abelian symmetry spontaneously. This new phase shows signatures known from superconductivity, such as an infinite dc conductivity and a gap in the frequency-dependent conductivity. The gravity setup allows for an explicit identification of the degrees of freedom in the dual field theory, as well as for a dual string picture of the condensation process.

Directed and elliptic flow measurements for charged pions and protons are reported as a function of transverse momentum, rapidity, and centrality for 40 and 158A GeV Pb + Pb collisions as recorded by the NA49 detector. Both the standard method of correlating particles with an event plane, and the cumulant method of studying multiparticle correlations are used. In the standard method the directed flow is corrected for conservation of momentum. In the cumulant method elliptic flow is reconstructed from genuine 4, 6, and 8-particle correlations, showing the first unequivocal evidence for collective motion in A+A collisions at SPS energies.

We present a systematic method for computing cosmological amplitudes, including in-in correlators and wavefunction coefficients, in FRW spacetime. Specializing to cases with conformally-coupled external scalars and massive scalar exchanges, we introduce a decomposition into massive family trees, which capture the nested time structure common to these observables. We then evaluate these building blocks using the Method of Brackets (MoB), a multivariate extension of Ramanujan's master theorem that operates directly on the integrand, translating integrals into discrete summations via a compact set of algebraic rules. This yields infinite series representations valid across the full space of external momenta and internal energies. We also develop Feynman-like diagrammatic rules that map interaction graphs to summand structures, enabling efficient and scalable computation. The resulting expressions make time evolution manifest, smoothly interpolate to the conformal limit, and are well suited for both numerical evaluation and analytic analysis of massive field effects in cosmology.

In this work, we provide a full map of scattering scenarios between a Nielsen-Olesen vortex and antivortex. Importantly, in the deep type II regime, such a collision reveals a chaotic pattern in the final state formation with bounce windows immersed into annihilation regions. This structure is due to the energy transfer mechanism triggered by a quasinormal mode, specifically the Feshbach resonant mode, hosted by the vortex.

Several experiments searching for direct dark matter interactions aim to achieve unprecedented sensitivity to sub-GeV/c$^2$ dark matter masses through elastic scattering with nuclei in various target crystals at cryogenic temperatures. Hydrogen-rich materials, such as organic compounds, are promising candidates for the detection of sub-GeV/c$^2$ dark matter due to favourable kinematics. In this paper, we present for the first time results obtained with a sugar-based phonon detector employing sucrose crystals ($\mathbf{C_{12}H_{22}O_{11}}$), capable of particle detection with associated scintillation light.

Null Wilson loops in $\mathcal{N}=4$ super Yang-Mills are dual to planar scattering amplitudes. This duality implies hidden symmetries for both objects. We consider closely related infrared finite observables, defined as the Wilson loop with a Lagrangian insertion, normalized by the Wilson loop itself. Unlike ratio and remainder functions studied in the literature, this observable is non-trivial already for four scattered particles and bears close resemblance to (finite parts of) scattering processes in non-supersymmetric Yang-Mills theory. We study the general structure of the Wilson loop with a Lagrangian insertion, focusing in particular on its leading singularities and their (hidden) symmetry properties. We find evidence that the leading singularities can be written as certain Grassmannian integrals. The latter are manifestly dual conformal. They also have a conformal symmetry, up to total derivatives. We find that, surprisingly, the conformal symmetry becomes an invariance in the frame where the Lagrangian insertion point is sent to infinity. Furthermore, we use integrability methods to study how higher Yangian charges act on the Grassmannian integral. We evaluate the $n$-particle observable both at tree- and at one-loop level, finding compact analytic formulas. These results are explicitly written in the form of conformal leading singularities, multiplied by transcendental functions. We then compare these formulas to known expressions for all-plus amplitudes in pure Yang-Mills theory. We find a remarkable new connection: the Wilson loop with Lagrangian insertion in $\mathcal{N}=4$ super Yang-Mills appears to predict the maximal weight terms of the planar pure Yang-Mills all-plus amplitude. We test this relationship for the two-loop $n$-point Yang-Mills amplitude, as well as for the three-loop four-point amplitude.

We present Version 9 of the Feynman-diagram calculator FormCalc and a flexible new suite of shell scripts and Mathematica packages based on FormCalc, which can be adapted and used as a template for calculations.

We point out that the de Sitter swampland conjecture would be falsified if classical fluxed Type IIA orientifold vacua with a single non-BPS D7-brane were indeed part of the string theory landscape. In other words, the dS swampland conjecture implies the cancellation of K-theory charges on a compact space.

We present the analytic formula for the Energy-Energy Correlation (EEC) in electron-positron annihilation computed in perturbative QCD to next-to-next-to-next-to-leading order (N$^3$LO) in the back-to-back limit. In particular, we consider the EEC arising from the annihilation of an electron-positron pair into a virtual photon as well as a Higgs boson and their subsequent inclusive decay into hadrons. Our computation is based on a factorization theorem of the EEC formulated within Soft-Collinear Effective Theory (SCET) for the back-to-back limit. We obtain the last missing ingredient for our computation - the jet function - from a recent calculation of the transverse-momentum dependent fragmentation function (TMDFF) at N$^3$LO. We combine the newly obtained N$^3$LO jet function with the well known hard and soft function to predict the EEC in the back-to-back limit. The leading transcendental contribution of our analytic formula agrees with previously obtained results in $\mathcal{N} = 4$ supersymmetric Yang-Mills theory. We obtain the $N=2$ Mellin moment of the bulk region of the EEC using momentum sum rules. Finally, we obtain the first resummation of the EEC in the back-to-back limit at N$^3$LL$^\prime$ accuracy, resulting in a factor of $\sim 4$ reduction of uncertainties in the peak region compared to N$^3$LL predictions.