We numerically investigate the interior of a four-dimensional, spherically symmetric charged black hole accreting neutral null fluid. Previous study by Marolf and Ori suggested that late infalling observers encounter an effective shock wave as they approach the outgoing portion of the inner horizon. Nonlinear perturbations could generate an effective gravitational shock wave, which manifests as a drop of the area coordinate $r$ from inner horizon value $r_{-}$ towards zero in an extremely short proper time duration of the infalling observer. We consider three different scenarios: a) A charged black hole accreting a single (ingoing) null fluid; b) a charged black hole perturbed by two null fluids, ingoing and outgoing; c) a charged black hole perturbed by an ingoing null fluid and a self-gravitating scalar field. While we do not observe any evidence for a gravitational shock in the first case, we detect the shock in the other two, using ingoing timelike and null geodesics. The shock width $\mathrm{\Delta }\tau$ decreases rapidly with a fairly good match to a new, generalized exponential law, $\mathrm{\Delta }\tau \sim e^{-\int {\kappa }_{-}({\tilde{V}}_f)d{\tilde{V}}_f}$, where ${\tilde{V}}_f$ is a specific timing parameter for the ingoing timelike geodesics and ${\kappa }_{-}({\tilde{V}}_f)$ is a generalized (Reissner-Nordström-like) surface gravity of the charged black hole at the inner horizon. We also gain new insight into the internal (classical) structure of a charged black hole perturbed by two null fluids, including strong evidence for the existence of a spacelike $r=0$ singularity. We use a finite-difference numerical code with double-null coordinates combined with an adaptive gauge method in order to solve the field equations from the region outside the black hole down to the vicinity of the $r=0$ singularity.

Motivated by tension between the predictions of ordinary cold dark matter (CDM) and observations at galactic scales, ultralight axionlike particles (ULALPs) with mass of the order ${10}^{-22}\mathrm{eV}$ have been proposed as an alternative CDM candidate. We consider cold and collisionless ULALPs produced in the early Universe by the vacuum realignment mechanism and constituting most of CDM. The ULALP fluid is commonly described by classical field equations. However, we show that, like QCD axions, the ULALPs thermalize by gravitational self-interactions and form a Bose-Einstein condensate, a quantum phenomenon. ULALPs, like QCD axions, explain the observational evidence for caustic rings of dark matter because they thermalize and go to the lowest energy state available to them. This is one of rigid rotation on the turnaround sphere. By studying the heating effect of infalling ULALPs on galactic disk stars and the thickness of the nearby caustic ring as observed from a triangular feature in the infrared astronomical satellite map of our galactic disk, we obtain lower-mass bounds on the ULALP mass of order ${10}^{-23}$ and ${10}^{-20}\mathrm{eV}$, respectively.

Many aspects of the large-scale structure of the Universe can be described successfully using cosmological models in which $27\pm 1\%$ of the critical mass-energy density consists of cold dark matter (CDM). However, few—if any—of the predictions of CDM models have been successful on scales of $\sim 10\mathrm{kpc}$ or less. This lack of success is usually explained by the difficulty of modeling baryonic physics (star formation, supernova and black-hole feedback, etc.). An intriguing alternative to CDM is that the dark matter is an extremely light ($m\sim {10}^{-22}\mathrm{eV}$) boson having a de Broglie wavelength $\lambda \sim 1\mathrm{kpc}$, often called fuzzy dark matter (FDM). We describe the arguments from particle physics that motivate FDM, review previous work on its astrophysical signatures, and analyze several unexplored aspects of its behavior. In particular, (i) FDM halos or subhalos smaller than about $10^7(m/{10}^{-22}\mathrm{eV}{)}^{-3/2}$ $M_{\odot }$ do not form, and the abundance of halos smaller than a few times $10^{10}(m/{10}^{-22}\mathrm{eV}{)}^{-4/3}$ $M_{\odot }$ is substantially smaller in FDM than in CDM. (ii) FDM halos are comprised of a central core that is a stationary, minimum-energy solution of the Schrödinger-Poisson equation, sometimes called a “soliton,” surrounded by an envelope that resembles a CDM halo. The soliton can produce a distinct signature in the rotation curves of FDM-dominated systems. (iii) The transition between soliton and envelope is determined by a relaxation process analogous to two-body relaxation in gravitating N-body systems, which proceeds as if the halo were composed of particles with mass $\sim \rho {\lambda }^3$ where $\rho$ is the halo density. (iv) Relaxation may have substantial effects on the stellar disk and bulge in the inner parts of disk galaxies, but has negligible effect on disk thickening or globular cluster disruption near the solar radius. (v) Relaxation can produce FDM disks but a FDM disk in the solar neighborhood must have a half-thickness of at least $\sim 300(m/{10}^{-22}\mathrm{eV}{)}^{-2/3}\mathrm{pc}$ and a midplane density less than $0.2(m/{10}^{-22}\mathrm{eV}{)}^{2/3}$ times the baryonic disk density. (vi) Solitonic FDM subhalos evaporate by tunneling through the tidal radius and this limits the minimum subhalo mass inside $\sim 30\mathrm{kpc}$ of the Milky Way to a few times $10^8(m/{10}^{-22}\mathrm{eV}{)}^{-3/2}$ $M_{\odot }$. (vii) If the dark matter in the Fornax dwarf galaxy is composed of CDM, most of the globular clusters observed in that galaxy should have long ago spiraled to its center, and this problem is resolved if the dark matter is FDM. (viii) FDM delays galaxy formation relative to CDM but its galaxy-formation history is consistent with current observations of high-redshift galaxies and the late reionization observed by Planck. If the dark matter is composed of FDM, most observations favor a particle mass $\gtrsim {10}^{-22}\mathrm{eV}$ and the most significant observational consequences occur if the mass is in the range $1–10\times {10}^{-22}\mathrm{eV}$. There is tension with observations of the Lyman-$\alpha$ forest, which favor $m\gtrsim 10–20\times {10}^{-22}\mathrm{eV}$ and we discuss whether more sophisticated models of reionization may resolve this tension.

We demonstrate that in the framework of standard general relativity, polytropic spheres with properly fixed polytropic index $n$ and relativistic parameter $\sigma$, giving a ratio of the central pressure $p_{\mathrm{c}}$ to the central energy density ${\rho }_{\mathrm{c}}$, can contain a region of trapped null geodesics. Such trapping polytropes can exist for $n>2.138$, and they are generally much more extended and massive than the observed neutron stars. We show that in the $n–\sigma$ parameter space, the region of allowed trapping increases with the polytropic index for intervals of physical interest, $2.138<n<4$. Space extension of the region of trapped null geodesics increases with both increasing $n$ and $\sigma >0.677$ from the allowed region. In order to relate the trapping phenomenon to astrophysically relevant situations, we restrict the validity of the polytropic configurations to their extension $r_{\mathrm{extr}}$ corresponding to the gravitational mass $M\sim 2M_{\odot }$ of the most massive observed neutron stars. Then, for the central density ${\rho }_{\mathrm{c}}\sim 10^{15}\mathrm{g}{\mathrm{cm}}^{-3}$, the trapped regions are outside $r_{\mathrm{extr}}$ for all values of $2.138<n<4$; for the central density ${\rho }_{\mathrm{c}}\sim 5\times 10^{15}\mathrm{g}{\mathrm{cm}}^{-3}$, the whole trapped regions are located inside $r_{\mathrm{extr}}$ for $2.138<n<3.1$; while for ${\rho }_{\mathrm{c}}\sim 10^{16}\mathrm{g}{\mathrm{cm}}^{-3}$, the whole trapped regions are inside $r_{\mathrm{extr}}$ for all values of $2.138<n<4$, guaranteeing astrophysically plausible trapping for all considered polytropes. The region of trapped null geodesics is located close to the polytrope center and could have a relevant influence on the cooling of such polytropes or binding of gravitational waves in their interior.

Motivated by the potential prospects of the $B_c^{*}$ meson samples at hadron colliders, the bottom-changing $B_c^{*}\to \psi (1S,2S)P$, ${\eta }_c(1S,2S)P$ weak decays are first studied with the perturbative QCD approach, where $P=\pi$ and $K$. It is found that the branching ratio of the Cabibbo-Kobayashi-Maskawa-favored $B_c^{*}\to J/\psi \pi$ decay is about $\sim \mathcal{O}(10^{-8})$, which might be measurable at the future LHC experiments.

We present a real-time lattice approach to study the nonequilibrium dynamics of vector and axial charges in $SU(N)\times U(1)$ gauge theories. Based on a classical description of the non-Abelian and Abelian gauge fields, we include dynamical fermions and develop operator definitions for (improved) Wilson and overlap fermions that allow us to study real-time manifestations of the axial anomaly from first principles. We present a first application of this approach to anomalous transport phenomena such as the chiral magnetic effect (CME) and the chiral separation effect (CSE) by studying the dynamics of fermions during and after a $SU(N)$ sphaleron transition in the presence of a $U(1)$ magnetic field. We investigate the fermion mass and magnetic field dependence of the suggested signatures of the CME and the CSE and point out some important aspects which need to be accounted for in the macroscopic description of anomalous transport phenomena.

Using the present upper bound on the neutron electric dipole moment, we give an estimate for the upper limit of the $CP$-violating couplings of the $\eta ({\eta }^{\prime })$ to the nucleon. Using this result, we then derive constraints on the $CP$-violating $\eta ({\eta }^{\prime })\pi \pi$ couplings, which define the two-pion $CP$-violating decays of the $\eta$ and ${\eta }^{\prime }$ mesons. Our results are relevant for the running and planned measurements of rare decays of the $\eta$ and ${\eta }^{\prime }$ mesons by the GlueX Collaboration at JLab and the LHCb Collaboration at CERN.

We investigate multilepton signatures, arising from the decays of doubly charged and singly charged Higgs bosons in the Type II seesaw model. Depending on the vacuum expectation value of the triplet $v_{\mathrm{\Delta }}$, the doubly and singly charged Higgs bosons can decay into a large variety of multilepton final states. We explore all possible decay modes corresponding to different regimes of $v_{\mathrm{\Delta }}$ that generate distinguishing four and five leptonic signatures. We focus on the 13 TeV Large Hadron Collider (LHC) and further extend the study to a very high energy proton-proton collider (VLHC) with a center-of-mass energy of 100 TeV. We find that a doubly charged Higgs boson of masses around 375 GeV can be discovered at immediate LHC runs. A heavier mass of 630 GeV can instead be discovered at the high-luminosity run of the LHC or at the VLHC with $30{\mathrm{fb}}^{-1}$.

We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and $W$ bosons. We use known constraints on the parameters of the model to compare the predicted size of these couplings with existing phenomenological constraints.

Several anomalies in the semileptonic B-meson decays such as $\mathcal{R}(D^{(*)})$ have been reported by the BABAR, Belle, and LHCb collaborations recently. In this paper, we investigate the contributions of the charged Higgs bosons from the 3-3-1 models to the $\mathcal{R}(D^{(*)})$ anomalies. We find that, in a wide range of parameter space, the 3-3-1 models might give reasonable explanations to the $\mathcal{R}(D^{(*)})$ anomalies and other analogous anomalies of the B meson’s semileptonic decays.

We explore the detection possibility of the light pseudoscalar Higgs boson in the next-to-minimal supersymmetric standard model (NMSSM) at the LHC with the center of mass energy, $\sqrt{S}=13\mathrm{TeV}$. We focus on the parameter space which provides one of the Higgs bosons as SM-like with a mass of 125 GeV and some of the non-SM-like Higgs bosons can be light having suppressed couplings with fermions and gauge bosons due to their singlet nature. It is observed that for a certain region of model parameter space, the singlet-like light pseudoscalar can decay to the diphoton ($\gamma \gamma$) channel with a substantial branching ratio. In this study, we consider this diphoton signal of a light pseudoscalar Higgs boson producing it through the chargino-neutralino production and the subsequent decay of the neutralino. We consider the signal consisting of two photons plus missing energy along with a lepton from the chargino decay. Performing a detailed simulation of the signal and backgrounds including detector effects, we present results for a few benchmark points corresponding to the pseudoscalar Higgs boson mass in the range 60–100 GeV. Our studies indicate that some of the benchmark points in the parameter space can be probed with a reasonable significance for $100{\mathrm{fb}}^{-1}$ integrated luminosity. We also conclude that exploiting this channel it is possible to distinguish the NMSSM from the other supersymmetric models.

Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass (${\varphi }_I\lesssim M_{\mathrm{Pl}}$). In order for a renormalization group (RG) improved effective $\lambda {\varphi }^4$ potential to develop an inflection point, the quartic coupling $\lambda (\varphi )$ must exhibit a minimum with an almost vanishing value in its RG evolution, namely $\lambda ({\varphi }_I)\simeq 0$ and ${\beta }_{\lambda }({\varphi }_I)\simeq 0$, where ${\beta }_{\lambda }$ is the beta function of the quartic coupling. As an example, we consider the minimal gauged $B-L$ extended Standard Model at the TeV scale, where we identify the $B-L$ Higgs field as the inflaton field. For a successful inflection-point inflation, which is consistent with the current cosmological observations, the mass ratios among the $Z^{\prime }$ gauge boson, the right-handed neutrinos and the $B-L$ Higgs boson are fixed. Our scenario can be tested in the future collider experiments such as the high-luminosity LHC and the SHiP experiments. In addition, the inflection-point inflation provides a unique prediction for the running of the spectral index $\alpha \simeq -2.7\times {10}^{-3}{(\frac{60}{N})}^2$ ($N$ is the $e$-folding number), which can be tested in the near future.

We examine the electroweak gauge sector of the noncommutative standard model and, in particular, obtain the $\mathcal{O}(\theta )$ Feynman rules for all quadrilinear gauge boson couplings. Surprisingly, an electroweak-chromodynamics mixing appears in the gauge sector of the noncommutative standard model, where the photon as well as the neutral weak boson is coupled directly to three gluons. The phenomenological perspectives of the model in $W^{-}{W}^{+}\to ZZ$ scattering are studied and it is shown that there is a characteristic oscillatory behavior in azimuthal distribution of scattering cross sections that can be interpreted as a direct signal of the noncommutative standard model. Assuming the integrated luminosity $100{\mathrm{fb}}^{-1}$, the number of $W^{-}{W}^{+}\to ZZ$ subprocesses are estimated for some values of noncommutative scale ${\mathrm{\Lambda }}_{\mathrm{NC}}$ at different center of mass energies and the results are compared with predictions of the standard model.

We present a calculation of the next-to-leading order QCD corrections to the hadroproduction process $gg\to ZZ\to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$, matched to the parton shower in the powheg framework. We take advantage of the powheg box tool for the implementation and rely on pythia8 for the showering and hadronization stages. We fully include ${\gamma }^{*}/Z$ interference effects, while also covering the single-resonant region. For this phenomenological study we focus on four lepton production as a signal process, neglecting all quark mass effects as well as the Higgs-mediated contributions, which are known to be subdominant in this case. We provide predictions from our simulations for the 13 TeV LHC Run II setup, including realistic experimental cuts.

There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in quantum chromodynamics, leading to the observed spectrum and properties of hadrons. Both the lattice and the Schwinger-Dyson communities have begun to calculate these form factors in various kinematical regimes of momenta involved. A natural consistency check for these studies is that they should match onto the perturbative predictions in the ultraviolet, where nonperturbative effects mellow down. In this article, we carry out a numerical analysis of the one-loop result for all the form factors of the quark-gluon vertex. Interestingly, even the one-loop results qualitatively encode most of the infrared enhancement features expected of their nonperturbative counter parts. We analyze various kinematical configurations of momenta: symmetric, on shell, and asymptotic. The on-shell limit enables us to compute anomalous chromomagnetic moment of quarks. The asymptotic results have implications for the multiplicative renormalizability of the quark propagator and its connection with the Landau-Khalatnikov-Fradkin transformations, allowing us to analyze and compare various Ansätze proposed so far.

In this paper we consider double-parton distribution functions (dPDFs), which are the main nonperturbative ingredients appearing in the double-parton scattering cross section formula in hadronic collisions. By using recent calculation of dPDFs by means of constituent quark models within the so-called light-front approach, we investigate the role of relativistic effects on dPDFs. We find, in particular, that the so-called Melosh operators, which allow us to properly convert the LF spin into the canonical one and incorporate a proper treatment of boosts, produce sizeable effects on dPDFs. We discuss specific partonic correlations induced by these operators in the transverse plane which are relevant to the proton structure, and we study under which conditions these results are stable against variations in the choice of the proton wave function.

We consider the $pp\to pp{\rho }^0{\pi }^0$ and $pp\to pn{\rho }^0{\pi }^{+}$ processes at LHC energies. Our description is based on the nonperturbative framework of tensor pomeron and tensor reggeon exchanges. We discuss the Drell-Hiida-Deck type mechanism with centrally produced ${\rho }^0$ meson associated with a very forward/backward $\pi N$ system. The considered processes constitute an inelastic (nonexclusive) background to the $pp\to pp{\rho }^0$ reaction in the case when only the centrally produced ${\rho }^0$ meson decaying into ${\pi }^{+}{\pi }^{-}$ is measured, the final state protons are not observed, and only rapidity-gap conditions are checked experimentally. We compare our results for the $\gamma {\pi }^{+}\to {\rho }^0{\pi }^{+}$ reaction with the experimental data obtained by the H1 collaboration at HERA. We present several differential distributions for the $pp\to pn{\rho }^0{\pi }^{+}$ reaction and estimate the size of the proton dissociative background to the exclusive $pp\to pp{\rho }^0$ process. The ratio of integrated cross sections for the inelastic $pp\to pN{\rho }^0\pi$ processes, where $pN{\rho }^0\pi$ stands for $pn{\rho }^0{\pi }^{+}$ plus $pp{\rho }^0{\pi }^0$, to the reference reaction $pp\to pp{\rho }^0$ is of order of (7–10)%. We present also the ratios of the ${\rho }^0$ rapidity and transverse momentum distributions for the inelastic $pp\to pN{\rho }^0\pi$ versus the elastic $pp\to pp{\rho }^0$ reaction. Our results may be used to investigate the $\gamma \pi \to {\rho }^0\pi$ process at LHC energies.

We investigate the interaction of spin-2 fields with those of the Standard Model in a model independent framework. We have considered interactions where the spin-2 fields couple to two sets of gauge invariant tensorial operators that are not conserved unlike the energy momentum tensor with different coupling strengths. Such interactions not only change the ultraviolet behavior of the couplings but also expand the scope of the searches of spin-2 particles at the colliders. We present all the relevant renormalization constants up to three loop level in QCD and also the form factors that contribute to potential observables. This sets the ground to investigate the phenomenological consequences of these interactions with spin-2 fields through more than one tensorial operator.

Neutrino-electron scattering is a purely leptonic fundamental interaction and therefore provides an important channel to test the Standard Model, especially at the low energy-momentum transfer regime. We derived constraints on neutrino nonstardard interaction couplings depending on model-independent approaches which are described by a four-Fermi pointlike interaction and the unparticle physics model with tensorial components. Data on ${\overline{\nu }}_e-\mathrm{e}$ and ${\nu }_e-\mathrm{e}$ scattering from the TEXONO and LSND experiments, respectively, are used. The upper limits and the allowed regions of scalar, pseudoscalar, and tensorial nonstandard interaction couplings of neutrinos are derived at 90% confidence level in both one-parameter and two-parameter analysis. New upper limits for tensorial unparticle physics coupling constants and mass parameters are also placed.

We present the first search for a dark matter annual modulation signal in the Southern Hemisphere conducted with NaI(Tl) detectors, performed by the DM-Ice17 experiment. Nuclear recoils from dark matter interactions are expected to yield an annually modulated signal independent of location within the Earth’s hemispheres. DM-Ice17, the first step in the DM-Ice experimental program, consists of 17 kg of NaI(Tl) located at the South Pole under 2200 m.w.e. overburden of Antarctic glacial ice. Taken over 3.6 years for a total exposure of 60.8 kg yr, DM-Ice17 data are consistent with no modulation in the energy range of 4–20 keV, providing the strongest limits on weakly interacting massive particle dark matter from a direct detection experiment located in the Southern Hemisphere. The successful deployment and stable long-term operation of DM-Ice17 establishes the South Pole ice as a viable location for future dark matter searches and in particular for a high-sensitivity NaI(Tl) dark matter experiment to directly test the DAMA/LIBRA claim of the observation of dark matter.