We present and compare several cosmological constraints on the cross section for elastic scattering between dark matter (DM) and baryons, for cross sections with a range of power-law dependences on the DM-baryon relative velocity $v$, especially focusing on the case of $\sigma \propto v^{-4}$. We study constraints spanning a wide range of epochs in cosmological history, from prerecombination distortions to the blackbody spectrum and anisotropies of the cosmic microwave background (CMB), to modifications to the intergalactic medium temperature and the resulting 21 cm signal, and discuss the allowed signals in the latter channels given the constraints from the former. We improve previous constraints on DM-baryon scattering from the CMB anisotropies, demonstrate via principal component analysis that the effect on the CMB can be written as a simple function of DM mass for $v^{-4}$ scattering, and map out the redshifts dominating this signal. We show that given high-redshift constraints on DM-baryon scattering, a $v^{-4}$ scaling of the cross section for light DM would be sufficient to explain the deep 21 cm absorption trough recently claimed by the Experiment to Detect the Reionization Step, if 100% of the DM scatters with baryons; we estimate the minimal necessary velocity scaling and find that it is close to $v^{-4}$. For millicharged DM models proposed to explain the observation, where only a small fraction of the DM interacts, we estimate that a PIXIE-like future experiment measuring CMB spectral distortion could test the relevant parameter space.

We calculate all those QCD $N$-point functions which are relevant for a three-loop QCD thermodynamics calculation with finite quark masses within the hard thermal loop approximation. Using the effective quark propagator, we also calculate second-order quark and baryon number susceptibilities within the hard thermal loop approximation and compare the results with available lattice data.

We study the cross section $\sigma$ and forward-backward asymmetry ($A_{\mathrm{FB}}$) in the process $pp\to {\gamma }^{*},Z\to {\ell }^{+}{\ell }^{-}$ (with $\ell =e$, $\mu$) for determinations of parton distribution functions (PDFs) of the proton. We show that, once mapped in the invariant mass of the dilepton final state, $M(\ell \ell )$, both observables, $\sigma$ and $A_{\mathrm{FB}}$, display a statistical error which is presently competitive with that assigned to the existing PDF sets and which will rapidly become smaller than the latter as the luminosity being accumulated at Run-II of the LHC grows. This statement is applicable to both on-peak and off-peak $M(\ell \ell )$ regions, both (just) below and above it, thereby offering a means of constraining the quark PDFs over a sizable $(x,Q^2)$ range.

We define the stretched future light cone, a timelike hypersurface composed of the worldlines of radially accelerating observers with constant and uniform proper acceleration. By attributing temperature and entropy to this hypersurface, we derive Einstein’s equations from the Clausius theorem. Moreover, we show that the gravitational equations of motion for a broad class of diffeomorphism-invariant theories of gravity can be obtained from thermodynamics on the stretched future light cone, provided the Bekenstein-Hawking entropy is replaced by the Wald entropy.

We study deformations of the quantum conformal mechanics of de Alfaro-Fubini-Furlan with a rational additional potential term generated by applying the generalized Darboux-Crum-Krein-Adler transformations to the quantum harmonic oscillator and by using the method of dual schemes and mirror diagrams. In this way we obtain infinite families of isospectral and nonisospectral deformations of the conformal mechanics model with special values of the coupling constant $g=m(m+1)$, $m\in \mathbb{N}$, in the inverse square potential term, and for each completely isospectral or gapped deformation given by a mirror diagram, we identify the sets of the spectrum-generating ladder operators that encode and coherently reflect its fine spectral structure. Each pair of these operators generates a nonlinear deformation of the conformal symmetry, and their complete sets pave the way for investigation of the associated superconformal symmetry deformations.

We consider the effect of including a nonminimal coupling between a $U(1)$ vector gauge field and the graviton Regge trajectory in holographic QCD models. This coupling describes the QCD interaction between the quark bilinear electromagnetic current and the Pomeron. We test this new coupling against DIS data at low Bjorken $x$ and obtain an excellent fit with a chi squared of 1.1 over a very large kinematical range in the photon virtuality $Q^2<400{\mathrm{GeV}}^2$ and for $x<{10}^{-2}$. The scale of the new dimension full coupling, which arises from integrating higher spin fields, is of order 1–10 GeV. This value matches precisely the expectations from effective field theory, which indicate that such corrections are controlled by the mass gap between the spin two and spin four glueballs that are described holographically by the graviton and spin four field in the graviton Regge trajectory, respectively.

The ability to directly detect gravitational waves has enabled us to empirically probe the nature of ultracompact relativistic objects. Several alternatives to the black holes of classical general relativity have been proposed which do not have a horizon, in which case a newly formed object (e.g., as a result of binary merger) may emit echoes: bursts of gravitational radiation with varying amplitude and duration, but arriving at regular time intervals. Unlike in previous template-based approaches, we present a morphology-independent search method to find echoes in the data from gravitational wave detectors, based on a decomposition of the signal in terms of generalized wavelets consisting of multiple sine-Gaussians. The ability of the method to discriminate between echoes and instrumental noise is assessed by inserting into the noise two different signals: a train of sine-Gaussians, and an echoing signal from an extreme mass-ratio inspiral of a particle into a Schwarzschild vacuum spacetime, with reflective boundary conditions close to the horizon. We find that both types of signals are detectable for plausible signal-to-noise ratios in existing detectors and their near-future upgrades. Finally, we show how the algorithm can provide a characterization of the echoes in terms of the time between successive bursts, and damping and widening from one echo to the next.

We study weak gravitational lensing around a compact object with arbitrary quadrupole moment in the presence of plasma. The studied compact objects are considered to be spherically symmetric. The additional parameter $\epsilon$ regulating the quadrupole moment in the metric alters the deflection angle of light rays along with the plasma parameters. In the vacuum, the number of images due to the presence of the parameter $\epsilon$ increases and causes the increase of the magnification of the image source. The effects of uniform and nonuniform plasma on gravitational lensing around the compact object are also studied.

Electromagnetic radiation emitted by a charged particle plunging from slightly below the innermost stable circular orbit into a Schwarzschild black hole is examined. Both even- and odd-parity electromagnetic perturbations are considered. They are described by using gauge invariant master functions and the regularized multipolar waveforms as well as their unregularized counterparts constructed from the quasinormal-mode spectrum are obtained for arbitrary directions of observation and, in particular, outside the orbital plane of the plunging particle. They are in excellent agreement and the results especially emphasize the impact of higher harmonics on the distortion of the waveforms.

The study of the cosmic-ray deuteron and antideuteron flux is receiving increasing attention in current astrophysics investigations. For both cases, an important contribution is expected from the nuclear interactions of primary cosmic rays with intergalactic matter. In this work, deuteron and antideuteron production from 20 to $2.6\times {10}^7\mathrm{GeV}$ beam energy in $\mathrm{p}+\mathrm{p}$ and $\mathrm{p}+\mathrm{A}$ collisions were simulated using EPOS-LHC and Geant4’s FTFP-BERT Monte Carlo models by adding an event-by-event coalescence model afterburner. These estimates depend on a single parameter ($p_0$) obtained from a fit to the data. The $p_0$ for deuterons in this wide energy range was evaluated for the first time. It was found that $p_0$ for antideuterons is not a constant at all energies as previous works suggested and, as a consequence, the antideuteron production cross section can be at least 20 times smaller in the low-collision-energy region than earlier estimations.

Gravitational waves have only two polarization modes in general relativity. However, there are six possible modes of polarization in a generic metric theory of gravity. Thus, tests of gravitational-wave polarization can be tools for pursuing the nature of space-time structure. The observations of gravitational waves with a worldwide network of interferometric detectors such as Advanced LIGO, Advanced Virgo, and KAGRA will make it possible to obtain the information of gravitational-wave polarization from detector signals. We study the separability of the polarization modes for the inspiral gravitational waves from the compact binary coalescences systematically. Unlike some other waveforms such as burst, the binary parameters need to be properly considered. We show that three polarization modes of gravitational waves would be separable with the global network of three detectors to some extent, depending on the signal-to-noise ratio and the duration of the signal. We also show that with four detectors the three polarization modes would be more easily distinguished by breaking a degeneracy of the polarization modes and even the four polarization modes would be separable.

We propose that neutrino masses can be zero in vacuo and may be generated by the local distribution of dark matter through a feeble long range scalar force. We discuss potential phenomenological constraints and implications of this framework. Our model typically implies that the cosmic neutrino background left over from the big bang is mostly absent in our Galactic neighborhood. Hence, a positive detection signal from future proposed experiments, such as PTOLEMY, could in principle falsify our scenario.

Sannomiya et al. have recently studied an extension of the Nicolai supersymmetric fermion lattice model, which is named “the extended Nicolai model.” The extended Nicolai model is parametrized by an adjustable constant $g\in \mathbb{R}$ in its defining supercharge and satisfies $\mathcal{N}=2$ supersymmetry. We show that for any nonzero $g$ the extended Nicolai model breaks supersymmetry dynamically, and the energy density of any homogeneous ground state for the model is strictly positive.

We establish model-independent sensitivity on the anomalous magnetic and electric dipole moments of the $\tau$-lepton using the two-photon processes $\gamma \gamma \to {\tau }^{+}{\tau }^{-}$ and $\gamma \gamma \to {\tau }^{+}{\tau }^{-}\gamma$. We use $\mathcal{L}=10$, 50, 100, 300, 500, 1000, 1500, 2000, $3000{\mathrm{fb}}^{-1}$ data collected with the future $e^{+}{e}^{-}$ linear collider such as the CLIC at $\sqrt{s}=380$, 1500, 3000 GeV, and we consider systematic uncertainties of ${\delta }_{\mathrm{sys}}=0\%$, 3%, 5%. We obtain sensitivity estimates at 95% C.L. on the anomalous dipole moments to the $\tau$-lepton $-0.00015\le {\tilde{a}}_{\tau }\le 0.00017$ and $|{\tilde{d}}_{\tau }(ecm)|=9.040\times {10}^{-19}$ that may be achievable in future experiments. Our results show that the processes under consideration are very promising for probing the dipole moments of the $\tau$-lepton at the future $e^{+}{e}^{-}$ linear collider at the $\gamma \gamma$ mode.

We perform the combined analysis of the double Higgs production via gluon fusion in the $b\overline{b}\gamma \gamma$ and $b\overline{b}{\tau }^{+}{\tau }^{-}$ decay channels at the High-Luminosity LHC (HL-LHC). To validate our analysis, we reproduce the ATLAS result of the $b\overline{b}\gamma \gamma$ process including all contributions from fakes. For the $b\overline{b}{\tau }^{+}{\tau }^{-}$ decay channel, we perform the similar analysis to the CMS one. As an improvement, we also perform the multivariate analysis employing the boosted decision tree algorithm. Then, we derive 68% probability contours on anomalous Higgs couplings in the effective field theory (EFT) approach for various analyses. We find that the $b\overline{b}{\tau }^{+}{\tau }^{-}$ process outperforms the $b\overline{b}\gamma \gamma$ for the measurement of energy-growing operators, while adding the $b\overline{b}{\tau }^{+}{\tau }^{-}$ process is least beneficial for improving the precision of the Higgs self-coupling (mainly set by the $b\overline{b}\gamma \gamma$ process). We illustrate that the double Higgs production alone can be comparable to the single Higgs process in constraining the modification of the top Yukawa coupling in the positive direction. Focusing on the Higgs self-coupling as a special interest, we derive the precision as a function of various improvable parameters such as tag and mistag rates of tau leptons, heavy flavor jets, photon identification, and diphoton mass resolution to take into account future phenomenological studies. As an optimistic benchmark scenario, we illustrate that the 68% and 95% probability intervals of the Higgs self-coupling, ${\lambda }_3/{\lambda }_3^{\mathrm{SM}}$, at the HL-LHC can reach [0.2, 2.3] and $[-0.1,3.5]\cup [4.0,6.5]$, respectively, where the correlation among the EFT coefficients is taken into account.

An explicit expression for the finite-volume energy shift of shallow three-body bound states for nonidentical particles is obtained in the unitary limit. The inclusion of the higher partial waves is considered. To this end, the method of Meißner, Rìos, and Rusetsky [Phys. Rev. Lett. 114, 091602 (2015)] is generalized for the case of unequal masses and arbitrary angular momenta. It is shown that in the S-wave and in the equal-mass limit, the result from Meißner, Rìos, and Rusetsky is reproduced.

We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic phase shifts for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The calculation is performed for two quark masses corresponding to pion masses of 315 and 227 MeV. The $\sigma$-meson parameters are extracted using various parametrizations of the scattering amplitude. The results obtained from a chiral unitary parametrization are extrapolated to the physical point and read $M_{\sigma }=(440_{-16}^{+10}(50)-i240(20)(25))\mathrm{MeV}$, where the uncertainties in the parentheses denote the stochastic and systematic ones. The behavior of the $\sigma$-meson parameters with increasing pion mass is discussed as well.

We provide a first calculation of the complete next-to-leading order QCD corrections for heavy flavor contributions to the inclusive structure function $g_1$ in longitudinally polarized deep-inelastic scattering. The results are derived with largely analytical methods and retain the full dependence on the heavy quark’s mass. We discuss all relevant technical details of the calculation and present numerical results for the heavy quark scaling functions. We perform important crosschecks to verify our results in the known limit of photoproduction and for the unpolarized electroproduction of heavy quarks. We also compare our calculations to the available, partial results in the polarized case, in particular, in the limit of asymptotically large photon virtualities, and analyze the behavior of the scaling functions near threshold. First steps towards phenomenological applications are taken by providing some estimates for inclusive charm production in polarized deep-inelastic scattering at a future electron-ion collider and studying their sensitivity to the polarized gluon distribution. The residual dependence of heavy quark electroproduction on unphysical factorization and renormalization scales and on the heavy quark mass is investigated.

We consider the effects of an external magnetic field on rotating fermions in $1+2$ and $1+3$ dimensions. The dual effect of a rotation parallel to the magnetic field causes a net increase in the fermionic density by centrifugation, which follows from the sinking of the particle lowest Landau level in the Dirac sea for free Dirac fermions. In $1+d=2n$ dimensions, this effect is related to the chiral magnetic effect in $2n-2$ dimensions. This phenomenon is discussed specifically for both weak and strong interfermion interactions in $1+2$ dimensions. For QCD in $1+3$ dimensions with Dirac quarks, we show that in the strongly coupled phase with spontaneously broken chiral symmetry, this mechanism reveals itself in the form of an induced pion condensation by centrifugation. We use this observation to show that this effect causes a shift in the chiral condensate at leading order in the pion interaction, and to discuss the possibility for the formation of a novel pion superfluid phase in off-central heavy-ion collisions at collider energies.

We calculate the cross section for the production of $D$ mesons and ${\mathrm{\Lambda }}_c$ baryons in proton-proton collisions at the LHC. The cross section for production of $c\overline{c}$ pairs is calculated within the $k_T$-factorization approach with the Kimber-Martin-Ryskin unintegrated gluon distributions obtained on the basis of modern collinear gluon distribution functions. We show that our approach well describes the $D^0$, $D^{+}$, and $D_s$ experimental data. We try to understand recent ALICE and LHCb data for ${\mathrm{\Lambda }}_c$ production with the $c\to {\mathrm{\Lambda }}_c$ independent parton fragmentation approach. The Peterson fragmentation functions are used. The $f_{c\to {\mathrm{\Lambda }}_c}$ fragmentation fraction and ${ϵ}_c^{\mathrm{\Lambda }}$ parameter for $c\to {\mathrm{\Lambda }}_c$ are varied. As a control plot we show the transverse momentum distributions of different species of $D$ mesons assuming standard values of the $f_{c\to D}$ fragmentation fractions known from the literature. Although one can agree with the ALICE data using the standard estimation of model uncertainties, one cannot describe simultaneously the ALICE and the LHCb data with the same set of parameters. The fraction $f_{c\to {\mathrm{\Lambda }}_c}$ necessary to describe the ALICE data is much larger than the average value obtained from $e^{+}{e}^{-}$ or $ep$ experiments. No drastic modification of the shape of the fragmentation function is allowed by the new ALICE and LHCb data for ${\mathrm{\Lambda }}_c$ production. We also discuss a possible dependence of the ${\mathrm{\Lambda }}_c/D^0$ baryon-to-meson ratio on rapidity and transverse momentum as recent observations by the ALICE and LHCb collaborations seem to suggest. Three different effects are considered: the value of the ${ϵ}_c^{\mathrm{\Lambda }}$ parameter in the Peterson fragmentation function for $c\to {\mathrm{\Lambda }}_c$, a kinematical effect related to the hadronization prescription, and a possible feed-down from higher charmed-baryon excitations. It seems very difficult, if not impossible, to understand the ALICE data within the considered independent parton fragmentation scheme.