One of the main goal of large-scale structure surveys is to test the consistency of general relativity at cosmological scales. In the $\mathrm{\Lambda }\mathrm{CDM}$ model of cosmology, the relations between the fields describing the geometry and the content of our Universe are uniquely determined. In particular, the two gravitational potentials—that describe the spatial and temporal fluctuations in the geometry—are equal. Whereas large classes of dark energy models preserve this equality, theories of modified gravity generally create a difference between the potentials, known as anisotropic stress. Even though measuring this anisotropic stress is one of the key goals of large-scale structure surveys, there are currently no methods able to measure it directly. Current methods all rely on measurements of galaxy peculiar velocities (through redshift-space distortions), from which the time component of the metric is inferred, assuming that dark matter follows geodesics. If this is not the case, all the proposed tests fail to measure the anisotropic stress. In this paper, we propose a novel test, $O^{\text{stress}}$, which directly measures anisotropic stress, without relying on any assumption about the unknown dark matter. Our method uses relativistic effects in the galaxy number counts to provide a direct measurement of the time component of the metric. By comparing this with lensing observations our test provides a direct measurement of the anisotropic stress.

Fast-pairwise neutrino oscillations potentially affect many aspects of core-collapse supernovae (CCSNe): the explosion mechanism, neutrino signals, and nucleosynthesis in the ejecta. This particular mode of collective neutrino oscillations has a deep connection to the angular structure of neutrinos in momentum space; for instance, the appearance of electron-neutrino lepton number (ELN) angular crossings in momentum space is a good indicator of the occurrence of flavor conversions. However, many multidimensional CCSN simulations are carried out with approximate neutrino transport (such as two-moment methods), which limits access to the angular distributions of neutrinos, i.e., inhibits ELN-crossing searches. In this paper, we develop a new method of searching for ELN crossing in these CCSN simulations. The required data is the zeroth and first angular moments of neutrinos and the matter profile, all of which are available in CCSN models with the two-moment method. One of the novelties of our new method is the use of a ray-tracing neutrino transport to determine ELNs in the direction of the stellar center. It is designed to compensate for shortcomings of the crossing searches with only two angular moments. We assess the capability of the method by carrying out a detailed comparison with results of full Boltzmann neutrino transport in 1D and 2D CCSN models. We find that the ray-tracing neutrino transport improves the accuracy of crossing searches; indeed, the appearance/disappearance of the crossings is accurately detected even in the region of forward-peaked angular distributions. The new method is computationally cheap and has the benefit of efficient parallelization; hence, it will be useful for ELN-crossing searches in any CCSN models that employ two-moment neutrino transport.

Recent breakthroughs in cryogenic silicon detector technology allow for the observation of single electron-hole pairs released via particle interactions within the target material. This implies sensitivity to energy depositions as low as the smallest band gap, which is $\sim 1.2\mathrm{eV}$ for silicon, and therefore sensitivity to $\mathrm{eV}/c^2$-scale bosonic dark matter and to thermal dark matter at masses below $100\mathrm{MeV}/c^2$. Various interaction channels that can probe the lowest currently accessible masses in direct searches are related to standard photoelectric absorption. In any of these respective dark matter signal models any uncertainty on the photoelectric absorption cross section is propagated into the resulting exclusion limit or into the significance of a potential observation. Using first-time precision measurements of the photoelectric absorption cross section in silicon recently performed at Stanford University, this article examines the importance having accurate knowledge of this parameter at low energies and cryogenic temperatures for these dark matter searches.

One of the most common expectations of a quantum theory of gravity is that spacetime is uncertain or fluctuating at microscopic scales, making it a stochastic medium for particle propagation. Particles traversing this spacetime may experience fluctuations in travel times or velocities, together referred to as lightcone fluctuations, with even very small effects potentially accumulating into observable signals over large distances. In this work we present a heuristic model of lightcone fluctuations and study the resulting modifications to neutrino propagation, including neutrino decoherence and arrival time spread. We show the expected scale of such effects due to “natural” Planck scale physics and consider how they may be observed in neutrino detectors, and compare the potential of neutrinos to $\gamma$-ray astronomy. Using simulations of neutrino mass states propagating in a fluctuating environment, we determine an analytic decoherence operator in the framework of open quantum systems to quantitatively evaluate neutrino decoherence resulting from lightcone fluctuations, allowing experimental constraints on neutrino decoherence to be connected to Planck scale fluctuations in spacetime and $\gamma$-ray results.

We study the two-Higgs-doublet model with a type-II seesaw mechanism. In view of constraints from the Higgs data, we consider the aligned two-Higgs-doublet scheme and its effects on muon anomalous magnetic dipole moment, $a_{\mu }$, including both one-loop and two-loop Barr-Zee type diagrams. Thanks to a sizable trilinear scalar coupling, the Barr-Zee type diagrams mediated by the Higgs triplet fields have a dominant effect on $a_{\mu }$. In particular, unlike the usual two-Higgs-doublet models that require exotic Higgs bosons light in mass, the masses of the corresponding particles in the model are of $\mathcal{O}(100)\mathrm{GeV}$. The doubly charged Higgs boson presents a different decay pattern from the usual Higgs triplet model and thus calls for a new collider search strategy, such as multi-$\tau$ searches at the LHC.

Right-handed neutrinos offer an elegant solution to two well-established phenomena beyond the Standard Model (SM)—masses and oscillations of neutrinos, as well as the baryon asymmetry of the Universe. It is also a minimalistic solution, since it requires only singlet Majorana fermions to be added to the SM particle content. If these fermions are nearly degenerate, the mass scale of right-handed neutrinos can be very low and accessible by the present and planned experiments. There are at least two well-studied mechanisms of low-scale leptogenesis: baryogenesis via oscillations and resonant leptogenesis. These two mechanisms were often considered separate, but they can, in fact, be understood as two different regimes of one and the same mechanism, described by a unique set of quantum kinetic equations. In this work, we show, using a unified description based on quantum kinetic equations, that the parameter spaces of these two regimes of low-scale leptogenesis significantly overlap. We present a comprehensive study of the parameter space of low-scale leptogenesis with the mass scale ranging from 0.1 to $\sim {10}^6\mathrm{GeV}$. The unified perspective of this work reveals the synergy between intensity and energy frontiers in the quest for heavy Majorana neutrinos.

The recently improved observation of the fine structure constant has led to a negative $2.4\sigma$ anomaly of electron $g-2$. Combined with the long-existing positive $4.2\sigma$ discrepancy of the muon anomalous magnetic moment, it is interesting and difficult to explain these two anomalies with a consistent model without introducing flavor violations. We show that they can be simultaneously explained in the inverse seesaw extended next-to-minimal supersymmetric standard model by the Higgsino-sneutrino contributions to $(g-2{)}_e$ and $(g-2{)}_{\mu }$. The spectrum features prefer light $\mu$, which can predict $m_Z$ naturally, and it is not difficult to obtain a $\tau$-type sneutrino dark matter candidate that is compatible with the observed dark matter relic density and the bounds from dark matter direct detection experiments. Due to the compressed spectra and the undetectable decay mode of selectrons, they can evade the current Large Hadron Collider constraints.

We propose a model which explains the baryon asymmetry of the universe and dark matter relic density at the same time. In this model, dark matter candidate is the dark baryon composed by dark quarks. A scalar mediator, which couples to the standard model leptons and dark quarks, is introduced to generate the asymmetry of baryon and dark baryon simultaneously. Direct detection and collider detection of this model are studied. We find that current underground direct detection experiments and LHC can hardly detect this model. But future lepton colliders, such as CEPC, have great potential to detect a large portion of the model parameter space, via novel signal “displaced lepton jet”.

In order to address the baryon asymmetry in the Universe one needs to understand the origin of baryon and lepton number violation. In this article, we discuss the mechanism of baryogenesis via leptogenesis to explain the matter-antimatter asymmetry in theories with spontaneous breaking of baryon and lepton number. In this context, a lepton asymmetry is generated through the out-of-equilibrium decays of right-handed neutrinos at the high-scale, while local baryon number must be broken below the multi-TeV scale to satisfy the cosmological bounds on the dark matter relic density. We demonstrate how the lepton asymmetry generated via leptogenesis can be converted in two different ways: (a) in the theory predicting Majorana dark matter the lepton asymmetry is converted into a baryon asymmetry, and (b) in the theory with Dirac dark matter the decays of right-handed neutrinos can generate lepton and dark matter asymmetries that are then partially converted into a baryon asymmetry. Consequently, we show how to explain the matter-antimatter asymmetry, the dark matter relic density and neutrino masses in theories for local baryon and lepton number.

Many extensions of the Standard Model predict the existence of new charged or neutral gauge bosons, with a wide variety of phenomenological implications depending on the model adopted. The search for such particles is extensively carried through at the Large Hadron Collider (LHC), and it is therefore of crucial importance to have for each proposed scenario quantitative predictions that can be matched to experiments. In this work we focus on the implications of one of these models, the top-flavor model (TF), proposing a charged $W^{\prime }$ boson that has preferential couplings to the third-generation fermions. We compare such predictions to the ones from the so-called sequential Standard Model (SSM), that is used as benchmark, being one of the simplest and most commonly considered models for searches at the LHC. We identify the parameter space still open for searches at the LHC, and we show that the cross sections for the processes $pp\to W^{\prime }\to \tau \nu$ and $pp\to W^{\prime }\to tb$ in the TF assume different values with respect to the SSM as a function of the particle mass and width and that the TF has realizations that would not be allowed in the SSM and not yet excluded by data. This study makes the case for further searches at the LHC and shows how a complete and systematic model-independent analysis of $W^{\prime }$ boson phenomenology at colliders is essential to provide guidance for future searches.

Heavy neutral leptons (HNLs) appear in many extensions of the Standard Model of particle physics. In this study, we investigate to which extent the NA62 experiment at CERN could improve the existing bounds on the HNL mixing angle $|U_e{|}^2$ by performing a missing mass search in $K^{+}\to {\pi }^0{e}^{+}N$ decays in flight. We show that the limit $|U_e{|}^2\simeq 2\times {10}^{-6}$ can be reached with the currently available data in the mass range 125–144 MeV, which is currently not well covered by production searches. Future data, together with a dedicated trigger and/or improvements in rejection of out-of-acceptance photons, can improve this limit by another order of magnitude.

In this work we discuss in detail the nonperturbative determination of the momentum dependence of the form factors entering in semileptonic decays using unitarity and analyticity constraints. The method contains several new elements with respect to previous proposals and allows to extract, using suitable two-point functions computed nonperturbatively, the form factors at low momentum transfer $q^2$ from those computed explicitly on the lattice at large $q^2$, without any assumption about their $q^2$-dependence. The approach will be very useful for exclusive semileptonic $B$-meson decays, where the direct calculation of the form factors at low $q^2$ is particularly difficult due to large statistical fluctuations and discretization effects. As a testing ground we apply our approach to the semileptonic $D\to K\ell {\nu }_{\ell }$ decay, where we can compare the results of the unitarity approach to the explicit direct lattice calculation of the form factors in the full $q^2$-range. We show that the method is very effective and that it allows to compute the form factors with rather good precision.

We calculate the magnetic moments of ground state $J^P={\frac{1}{2}}^{+}$ and $J^P={\frac{3}{2}}^{+}$ heavy flavor charm and bottom baryon states employing the concept of effective mass based on single gluon exchange interaction coupling to the spectator quarks in the nonrelativistic quark model. We exploit the current experimental information in the heavy flavor sector to estimate the interaction contributions to get the effective masses of the quarks inside the baryons. We study the spin ${\frac{1}{2}}^{\prime +}\to {\frac{1}{2}}^{+}$, ${\frac{3}{2}}^{+}\to {\frac{1}{2}}^{+}$, and ${\frac{3}{2}}^{+}\to {\frac{1}{2}}^{\prime +}$ transition moments for these baryons. We make robust predictions of the radiative $M1$ decay widths of singly, doubly, and triply heavy flavored baryons.

A unified treatment of both chiral and radiative corrections to the low-energy elastic lepton-proton scattering processes is presented in Heavy Baryon Chiral Perturbations Theory. The proton hadronic chiral corrections include the next-to-next-to-leading-order corrections, whereas the radiative corrections include the next-to-leading-order terms in our novel power counting scheme. We find that the net fractional well-defined chiral corrections with respect to the leading-order Born cross section can be as large as 10% (20%) for electron (muon) scattering process for MUon Proton Scattering Experiment (MUSE) kinematics. We show via our model-independent treatment of the low-energy lepton-proton kinematics that the largest theoretical uncertainty is due to the recent different published values of the proton’s rms radius, while, e.g., the next-higher-order hadronic chiral terms are expected to give rather nominal errors. For the radiative corrections, we demonstrate a systematic order by order cancellation of all infrared singularities and present our finite ultraviolet regularization results. We find that the radiative corrections for muon-proton scattering is of the order of 2%, whereas for electron scattering, the radiative corrections could be as large as 25%. We attribute such a contrasting result partially to the fact that in muon scattering the leading radiative-order correction goes through zero in some intermediate low-momentum transfer region, leaving the subleading radiative chiral-order effects to play a dominant role in this particular kinematic region. For the low-energy MUSE experiment, the often-neglected lepton mass as well as the Pauli form factor contributions of the relativistic leptons are incorporated in all our computations.

Using $980{\mathrm{fb}}^{-1}$ of data collected with the Belle detector operating at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the ${\mathrm{\Sigma }}_c(2455{)}^{+}$ and ${\mathrm{\Sigma }}_c(2520{)}^{+}$ charmed baryons. We find $M({\mathrm{\Sigma }}_c(2455{)}^{+})-M({\mathrm{\Lambda }}_c^{+})=166.17\pm 0.05_{-0.07}^{+0.16}\mathrm{MeV}/c^2$, $\mathrm{\Gamma }({\mathrm{\Sigma }}_c(2455{)}^{+})=2.3\pm 0.3\pm 0.3\mathrm{MeV}/c^2$, $M({\mathrm{\Sigma }}_c(2520{)}^{+})-M({\mathrm{\Lambda }}_c^{+})=230.9\pm 0.5_{-0.1}^{+0.5}\mathrm{MeV}/c^2$, and $\mathrm{\Gamma }({\mathrm{\Sigma }}_c(2520{)}^{+})={17.2}_{-2.1-0.7}^{+2.3+3.1}\mathrm{MeV}/c^2$, where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the ${\mathrm{\Sigma }}_c$ states.

We present a measurement of the combined ${\nu }_e+{\overline{\nu }}_e$ flux-averaged charged-current inclusive cross section on argon using data from the MicroBooNE liquid argon time projection chamber (lartpc) at Fermilab. Using the off-axis flux from the NuMI beam, MicroBooNE has reconstructed 214 candidate ${\nu }_e+{\overline{\nu }}_e$ interactions with an estimated exposure of $2.4\times {10}^{20}$ protons on target. Given the estimated purity of 38.6%, this implies the observation of 80 ${\nu }_e+{\overline{\nu }}_e$ events in argon, the largest such sample to date. The analysis includes the first demonstration of a fully automated application of a dE/dx-based particle discrimination technique of electron- and photon-induced showers in a lartpc neutrino detector. The main background for this first ${\nu }_e$ analysis is cosmic ray contamination. Significantly higher purity is expected in underground detectors, as well as with next-generation reconstruction algorithms. We measure the ${\nu }_e+{\overline{\nu }}_e$ flux-averaged charged-current total cross section to be $6.84\pm 1.51(\mathrm{stat})\pm 2.33(\mathrm{sys})\times {10}^{-39}{\mathrm{cm}}^2/\text{nucleon}$, for neutrino energies above 250 MeV and an average neutrino flux energy of 905 MeV when this threshold is applied. The measurement is sensitive to neutrino events where the final state electron momentum is above $48\mathrm{MeV}/\mathrm{c}$, includes the entire angular phase space of the electron, and is in agreement with the theoretical predictions from genie and nuwro. This measurement is also the first demonstration of electron-neutrino reconstruction in a surface lartpc in the presence of cosmic-ray backgrounds, which will be a crucial task for surface experiments like those that comprise the short-baseline neutrino program at Fermilab.

We offer a new solution to an old puzzle in the penguin-dominated $B\to \pi K$ decays. The puzzle is the inconsistency among the measurements of the branching ratios and $CP$ asymmetries of the four $B\to \pi K$ decays: $B^{+}\to {\pi }^{+}{K}^0$, $B^{+}\to {\pi }^0{K}^{+}$, $B_d^0\to {\pi }^{-}{K}^{+}$, $B_d^0\to {\pi }^0{K}^0$. We solve the $B\to \pi K$ puzzle by considering the effect of an axionlike particle (ALP) that mixes with the ${\pi }^0$ and has mass close to the ${\pi }^0$ mass. We show that the ALP can also explain the anomalies in the electron and muon anomalous magnetic moments.

We present a framework to simulate the dynamics of hard probes such as heavy quarks or jets in a hot, strongly coupled quark-gluon plasma (QGP) on a quantum computer. Hard probes in the QGP can be treated as open quantum systems governed in the Markovian limit by the Lindblad equation. However, due to large computational costs, most current phenomenological calculations of hard probes evolving in the QGP use semiclassical approximations of the quantum evolution. Quantum computation can mitigate these costs and offers the potential for a fully quantum treatment with exponential speed-up over classical techniques. We report a simplified demonstration of our framework on IBM Q quantum devices and apply the random identity insertion method to account for cnot depolarization noise, in addition to measurement error mitigation. Our work demonstrates the feasibility of simulating open quantum systems on current and near-term quantum devices, which is of broad relevance to applications in nuclear physics, quantum information, and other fields.

By constructing the configuration of D3-branes with D(-1)-branes as D-instantons, we study the three-dimensional Yang-Mills-Chern-Simons theory in holography. Because of the presence of the D-instantons, the D7-branes with discrepant embedding functions are able to be introduced in order to include the fundamental fermions (as flavors) and the Chern-Simons term (at very low energy) in the dual theory. The vacuum structure at zero temperature is studied in the soliton background, and it illustrates the topological phase transition in the presence of instantons. Moreover, since the confinement/deconfinement phase transition could be holographically identified as the Hawking-Page transition in the bulk, we accordingly calculate the critical temperature of the deconfinement phase transition by collecting the bulk on-shell action as the thermodynamical free energy. On the other hand, we evaluate the difference of the entanglement entropy in slab configuration by using the Ryu-Takayanagi formula since the confinement may also be characterized by the entanglement entropy. Altogether we find the behavior of the critical temperature is in qualitative agreement with the behavior of the critical length determined by the entanglement entropy which implies the entanglement entropy could indeed be a character of the confinement in our setup and the D3-D(-1) system would be a remarkable approach to study the three-dimensional gauge theory.