We report on the dataset, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the $\beta$-decay kinematics of molecular tritium. The source is highly pure, cryogenic ${\mathrm{T}}_2$ gas. The $\beta$ electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts $\beta$ electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmology.

We compute corrections of order ${\alpha }_s^3$ to the decay $b\to c\ell \overline{\nu }$ taking into account massive charm quarks. In the on-shell scheme large three-loop corrections are found. However, in the kinetic scheme the three-loop corrections are below 1% and thus perturbation theory is well under control. We furthermore provide results for the order ${\alpha }_s^3$ corrections to $b\to u\ell \overline{\nu }$ and the third-order QED corrections to the muon decay which will be important input for reducing the uncertainty of the Fermi coupling constant $G_F$.

We apply the method of graphical functions that was recently extended to six dimensions for scalar theories, to ${\varphi }^3$ theory and compute the $\beta$ function, the wave function anomalous dimension as well as the mass anomalous dimension in the $\overline{\mathrm{MS}}$ scheme to five-loops. From the results we derive the corresponding renormalization group functions for the Lee-Yang edge singularity problem and percolation theory. After determining the $ϵ$ expansions of the respective critical exponents to $\mathcal{O}({ϵ}^5)$ we apply recent resummation technology to obtain improved exponent estimates in three, four and five dimensions. These compare favorably with estimates from fixed dimension numerical techniques and refine the four loop results. To assist with this comparison we collated a substantial amount of data from numerical techniques which are included in tables for each exponent.

Germanium is the detector material of choice in many rare-event searches looking for low-energy nuclear recoils induced by dark matter particles or neutrinos. We perform a systematic exploration of its quenching factor for sub-keV nuclear recoils, using multiple techniques: photoneutron sources, recoils from gamma-emission following thermal neutron capture, and a monochromatic filtered neutron beam. Our results point to a marked deviation from the predictions of the Lindhard model in this mostly unexplored energy range. We comment on the compatibility of our data with low-energy processes such as the Migdal effect, and on the impact of our measurements on upcoming searches.

We propose a novel method to probe the persistent hints of lepton flavor universality violation observed in semileptonic $B$ decays. Relying on the specific properties of the Belle II experiment, it consists in comparing the inclusive rates of $\mathrm{\Upsilon }(4S)\to e^{\pm }{\mu }^{\mp }X$, $\mathrm{\Upsilon }(4S)\to {\mu }^{\pm }{\tau }_{\mathrm{had}}^{\mp }X$ and $\mathrm{\Upsilon }(4S)\to e^{\pm }{\tau }_{\mathrm{had}}^{\mp }X$. We show that such a measurement can be directly related to the ratio $R(X{)}_{\tau \ell }\equiv \mathrm{\Gamma }(B\to X\tau \nu )/\mathrm{\Gamma }(B\to X\ell \nu )$ ($\ell =e$ or $\mu$), once appropriate experimental cuts are applied to suppress the effects of neutral $B$ mixing and leptons emitted through charm or tau decays. Such a measurement would thus constitute an additional and potentially competitive probe of lepton flavor universality in $b\to c\ell \nu$ transitions, complementary to existing exclusive measurements, accessible in the Belle II environment.

Existing searches for cosmic axions relics have relied heavily on the axion being nonrelativistic and making up dark matter. However, light axions can be copiously produced in the early Universe and remain relativistic today, thereby constituting a Cosmic axion Background ($\mathrm{C}a\mathrm{B}$). As prototypical examples of axion sources, we consider thermal production, dark-matter decay, parametric resonance, and topological defect decay. Each of these has a characteristic frequency spectrum that can be searched for in axion direct detection experiments. We focus on the axion-photon coupling and study the sensitivity of current and future versions of ADMX, HAYSTAC, DMRadio, and ABRACADABRA to a $\mathrm{C}a\mathrm{B}$, finding that the data collected in search of dark matter can be repurposed to detect axion energy densities well below limits set by measurements of the energy budget of the Universe. In this way, direct detection of relativistic relics offers a powerful new opportunity to learn about the early Universe and, potentially, discover the axion.

We study the index of 4d $\mathcal{N}=4$ Yang-Mills theory with $U(N)$ gauge group, focusing on the physics of the dual Bogomolny-Prasad-Sommerfield black holes in ${\mathrm{AdS}}_5\times S^5$. Certain aspects of these black holes can be studied from finite $N$ indices with reasonably large $N^2$. We make numerical studies of the index for $N\le 6$, by expanding it up to reasonably high orders in the fugacity. The entropy of the index agrees very well with the Bekenstein-Hawking entropy of the dual black holes, say at $N^2=25$ or 36. Our data clarifies and supports the recent ideas which allowed analytic studies of these black holes from the index, such as the complex saddle points of the Legendre transformation and the oscillating signs in the index. In particular, the complex saddle points naturally explain the $\frac{1}{N}$-subleading oscillating patterns of the index. We also illustrate the universality of our ideas by studying a model given by the inverse of the MacMahon function.

A measurement of the sum of neutrino masses is one of the main applications of upcoming measurements of gravitational lensing of the cosmic microwave background (CMB). This measurement can be confounded by modelling uncertainties related to so-called “baryonic effects” on the clustering of matter, arising from gas dynamics, star formation, and feedback from active galactic nuclei and supernovae. In particular, a wrong assumption about the form of baryonic effects on CMB lensing can bias a neutrino mass measurement by a significant fraction of the statistical uncertainty. In this paper, we investigate three methods for mitigating this bias: (1) restricting the use of small-scale CMB lensing information when constraining neutrino mass; (2) using an external tracer to remove the low-redshift contribution to a CMB lensing map; and (3) marginalizing over a parametric model for baryonic effects on large-scale structure. We test these methods using Fisher matrix forecasts for experiments resembling the Simons Observatory and CMB-S4, using a variety of recent hydrodynamical simulations to represent the range of possible baryonic effects, and using cosmic shear measured by the Rubin Observatory’s LSST as the tracer in method (2). We find that a combination of (1) and (2), or (3) on its own, will be effective in reducing the bias induced by baryonic effects on a neutrino mass measurement to a negligible level, without a significant increase in the associated statistical uncertainty.

ANAIS (annual modulation with NaI scintillators) is a dark matter direct detection experiment consisting of 112.5 kg of NaI(Tl) detectors in operation at the Canfranc Underground Laboratory (LSC), in Spain, since August 2017. ANAIS’ goal is to confirm or refute in a model independent way the DAMA/LIBRA positive result: an annual modulation in the low-energy detection rate having all the features expected for the signal induced by dark matter particles in a standard galactic halo. This modulation, observed for about 20 years, is in strong tension with the negative results of other very sensitive experiments, but a model-independent comparison is still lacking. By using the same target material, NaI(Tl), such a comparison is more direct and almost independent in dark matter particle and halo models. Here, we present the annual modulation analysis corresponding to three years of ANAIS data (for an effective exposure of $313.95\mathrm{kg}\times \mathrm{y}$), applying a blind procedure, which updates the one developed for the 1.5 years analysis, and later applied to 2 years. The analysis also improves the background modeling in the fitting of the region of interest rates. We obtain for the best fit in the [1–6] keV ([2–6] keV) energy region a modulation amplitude of $-0.0034\pm 0.0042\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ ($0.0003\pm 0.0037\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$), supporting the absence of modulation in our data, and incompatible with the DAMA/LIBRA result at 3.3 (2.6) $\sigma$, for a sensitivity of 2.5 (2.7) $\sigma$. Moreover, we include two complementary analyses: a phase-free annual modulation search and the exploration of the possible presence of a periodic signal at other frequencies. Finally, we carry out several consistency checks of our result, and we update the ANAIS-112 projected sensitivity for the scheduled 5 years of operation.

We report high-precision measurements of the longitudinal double-spin asymmetry, $A_{LL}$, for midrapidity inclusive jet and dijet production in polarized $pp$ collisions at a center-of-mass energy of $\sqrt{s}=200\mathrm{GeV}$. The new inclusive jet data are sensitive to the gluon helicity distribution, $\mathrm{\Delta }g(x,Q^2)$, for gluon momentum fractions in the range from $x\simeq 0.05$ to $x\simeq 0.5$, while the new dijet data provide further constraints on the $x$ dependence of $\mathrm{\Delta }g(x,Q^2)$. The results are in good agreement with previous measurements at $\sqrt{s}=200\mathrm{GeV}$ and with recent theoretical evaluations of prior world data. Our new results have better precision and thus strengthen the evidence that $\mathrm{\Delta }g(x,Q^2)$ is positive for $x>0.05$.

The distance ladder using supernovae yields higher values of the Hubble constant $H_0$ than those inferred from measurements of the cosmic microwave background (CMB) and galaxy surveys, a discrepancy that has come to be known as the “Hubble tension”. This has motivated the exploration of extensions to the standard cosmological model in which higher values of $H_0$ can be obtained from CMB measurements and galaxy surveys. The trouble, however, goes beyond $H_0$; such modifications affect other quantities, too. In particular, their effects on cosmic times are usually neglected. We explore here the implications that measurements of the age $t_{\mathrm{U}}$ of the Universe, such as a recent inference from the age of the oldest globular clusters, can have for potential solutions to the $H_0$ tension. The value of $H_0$ inferred from the CMB and galaxy surveys is related to the sound horizon at CMB decoupling (or at radiation drag), but it is also related to the matter density and to $t_{\mathrm{U}}$. Given this observation, we show how model-independent measurements may support or disfavor proposed new-physics solutions to the Hubble tension. Finally, we argue that cosmological measurements today provide constraints that, within a given cosmological model, represent an overconstrained system, offering a powerful diagnostic tool of consistency. We propose the use of ternary plots to simultaneously visualize independent constraints on key quantities related to $H_0$ like $t_{\mathrm{U}}$, the sound horizon at radiation drag, and the matter density parameter. We envision that this representation will help find a solution to the trouble of and beyond $H_0$.

We put forward novel extensions of Starobinsky inflation, involving a class of “geometric” higher-curvature corrections that yield second-order Friedmann-Lemaître equations and second-order-in-time linearized equations around cosmological backgrounds. We determine the range of models within this class that admit an extended phase of slow roll inflation as an attractor. By embedding these theories in anti-de Sitter space, we derive holographic “unitarity” bounds on the two dominant higher-order curvature corrections. Finally we compute the leading corrections to the spectral properties of scalar and tensor primordial perturbations, including the modified consistency relation $r=-8n_T$. Remarkably, the range of models singled out by holography nearly coincides with the current observational bounds on the scalar spectral tilt. Our results indicate that future observations have the potential to discriminate between different higher-curvature corrections considered here.

We present an effective-field-theory-based reconstruction of quintessence models of dark energy directly from cosmological data. We show that current cosmological data possess enough constraining power to test several quintessence model properties for redshifts $z\in [0,1.5]$ with no assumptions about the behavior of the scalar field potential. We use measurements of the cosmic microwave background, supernova distances, and the clustering and lensing of galaxies to constrain the evolution of the dark energy equation of state, swampland conjectures, the shape of the scalar field reconstructed potential, and the structure of its phase space. The standard cosmological model still remains favored by data and, within quintessence models, deviations from its expansion history are bounded to be below the 10% level at 95% confidence at any redshift below $z=1.5$.

We calculate eccentricities in high energy proton-nucleus collisions, by calculating correlation functions of the energy density field of the glasma immediately after the collision event at proper time $\tau =0^{+}$. We separately consider the effects of color charge and geometrical hot spot fluctuations, analytically performing the averages over both in a dilute-dense limit. We show that geometric fluctuations of hot spots inside the proton are the dominant source of eccentricity whereas color charge fluctuations only give a negligible correction. The size and number of hot spots are the most important parameters characterizing the eccentricities.

The scattering equivalence of quantum field theories formulated with light-front and instant-form kinematic subgroups is established using nonperturbative methods. The difficulty with field theoretic formulations of Dirac’s forms of dynamics is that the free and interacting unitary representations of the Poincaré group are defined on inequivalent representations of the Hilbert space, which means that the concept of kinematic transformations must be modified on the Hilbert space of the field theory. This work addresses this problem by assuming the existence of a field theory with the expected properties and constructs equivalent representations with instant and front-form kinematic subgroups. The underlying field theory is not initially associated with an instant form or light-front form of the dynamics. In this construction the existence of a vacuum and one-particle mass eigenstates is assumed and both the light-front and instant-form representations are constructed to share the same vacuum and one-particle states. If there is spontaneous symmetry breaking there will be a 0 mass particle in the mass spectrum (assuming no Higgs mechanism). The free field Fock space plays no role. There is no “quantization” of a classical theory. The property that survives from the perturbative approach is the notion of a kinematic subgroup, which means kinematic Poincaré transformations can be trivially implemented by acting on suitable basis vectors. This nonperturbative approach avoids dealing with issues that arise in perturbative treatments where is it necessary to have a consistent treatment of renormalization, rotational covariance, and the structure of the light-front vacuum. While addressing these issues in a computational framework is the most important unanswered question for applications, this work may provide some insight into the nature of the expected resolution and identifies the origin of some of differences between the perturbative and nonperturbative approaches.

Maintaining local interactions in the quantum simulation of gauge field theories relegates most states in the Hilbert space to be unphysical—theoretically benign, but experimentally difficult to avoid. Reformulations of the gauge fields can modify the ratio of physical to gauge-variant states often through classically preprocessing the Hilbert space and modifying the representation of the field on qubit degrees of freedom. This paper considers the implications of representing SU(3) Yang-Mills gauge theory on a lattice of irreducible representations in both a global basis of projected global quantum numbers and a local basis in which controlled-plaquette operators support efficient time evolution. Classically integrating over the internal gauge space at each vertex (e.g., color isospin and color hypercharge) significantly reduces both the qubit requirements and the dimensionality of the unphysical Hilbert space. Initiating tuning procedures that may inform future calculations at scale, the time evolution of one and two plaquettes are implemented on one of IBM’s superconducting quantum devices, and early benchmark quantities are identified. The potential advantages of qudit environments, with either constrained two-dimensional hexagonal or one-dimensional nearest-neighbor internal state connectivity, are discussed for future large-scale calculations.

Prior to the epoch of reionization, the 21-cm signal of the cosmic dawn is dominated by the Lyman-$\alpha$ coupling and gas temperature fluctuations caused by the first sources of radiation. While early efforts to model this epoch relied on analytical techniques, the community quickly transitioned to more expensive seminumerical models. Here, we reassess the viability of simpler approaches that allow for rapid explorations of the vast astrophysical parameter space. We propose a new analytical method to calculate the 21-cm power spectrum based on the framework of the halo model. Both the Lyman-$\alpha$ coupling and temperature fluctuations are described by overlapping radiation flux profiles that include spectral redshifting and source attenuation due to look-back (light-cone) effects. The 21-cm halo model is compared to the seminumerical code 21 cmFAST exhibiting generally good agreement, i.e., the power spectra differ by less than a factor of 3 over a large range of $k$-modes and redshifts. We show that the remaining differences between the two methods are comparable to the expected variations from modeling uncertainties associated with the abundance, bias, and accretion rates of haloes. While these current uncertainties must be reduced in the future, our work suggests that inference at acceptable accuracy will become feasible with very efficient halo models of the cosmic dawn.

Local determinations of the Hubble constant $H_0$ favor a higher value than Planck based on cosmic microwave background and $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$). Through a model-independent expansion, we show that low redshift ($z\lesssim 0.7$) data comprising baryon acoustic oscillations, cosmic chronometers, and Type Ia supernovae have a preference for quintessence models that lower $H_0$ relative to $\mathrm{\Lambda }\mathrm{CDM}$. In addition, we confirm that an exponential coupling to dark matter cannot alter this conclusion in the same redshift range. Our results leave open the possibility that a coupling in the matter-dominated epoch, potentially even in the dark ages, may yet save $H_0$ from sinking in the string theory swampland.

The requirement of diffeomorphism symmetry for the target space can lead to anomalous commutators for the energy-momentum tensor for sigma models and for fluid dynamics, if certain topological terms are added to the action. We analyze several examples. A particular topological term is shown to lead to the known effective hydrodynamics of a dense collection of vortices, i.e., the vortex fluid theory in $2+1$ dimensions. The possibility of a similar vortex fluid in $3+1$ dimensions, as well as a fluid of knots and links, with possible extended diffeomorphism algebras is also discussed.

The next generation of ultralight dark matter (DM) direct detection experiments, which could confirm sub-eV bosons as the dominant source of DM, will feature multiple detectors operating at various terrestrial locations. As a result of the wavelike nature of ultralight DM, spatially separated detectors will each measure a unique DM phase. When the separation between experiments is comparable to the DM coherence length, the spatially varying phase contains information beyond that which is accessible at a single detector. We introduce a formalism to extract this information, which performs interferometry directly on the DM wave. In particular, we develop a likelihood-based framework that combines data from multiple experiments to constrain directional information about the DM phase space distribution. We show that the signal in multiple detectors is subject to a daily modulation effect unique to wavelike DM. Leveraging daily modulation, we illustrate that within days of an initial discovery multiple detectors acting in unison could localize directional parameters of the DM velocity distribution such as the direction of the solar velocity to subdegree accuracy, or the direction of a putative cold DM stream to the subarcminute level. We outline how to optimize the locations of multiple detectors with either resonant cavity (such as ADMX or HAYSTAC) or quasistatic (such as ABRACADABRA or DM-Radio) readouts to have maximal sensitivity to the full three-dimensional DM velocity distribution.