We analyze the quantum supersymmetric cosmological Friedmann-Robertson-Walker model with a scalar field, with a conditional probability density and the scalar field identified as time. The Hilbert space has a spinorial structure and there is only one consistent solution, with a conserved probability density. The dynamics of the scale factor is obtained from its mean value. The uncertainty relations are fulfilled and the corresponding fluctuations are consistent with a semiclassical Universe. We give two examples which turn out to have negative potential.

We propose a general method to analytically solve transport equations during a phase transition without making approximations based on the assumption that any transport coefficient is large. Using a cosmic phase transition in the minimal supersymmetric standard model as a pedagogical example, we derive the solutions to a set of 3 transport equations derived under the assumption of supergauge equilibrium and the diffusion approximation. The result is then rederived efficiently using a technique we present involving a parametrized ansatz which turns the process of deriving a solution into an almost elementary problem. We then show how both the derivation and the parametrized ansatz technique can be generalized to solve an arbitrary number of transport equations. Finally we derive a perturbative series that relaxes the usual approximation that inactivates vacuum-expectation-value dependent relaxation and $CP$-violating source terms at the bubble wall and through the symmetric phase. Our analytical methods are able to reproduce a numerical calculation in the literature.

We exploit a new numerical technique for evaluating the tree order contributions to the primordial scalar and tensor power spectra for scalar potential models of inflation. Among other things we use the formalism to develop a good analytic approximation which goes beyond generalized slow roll expansions in that (1) it is not contaminated by the physically irrelevant phase, (2) its 0th order term is exact for the constant first slow roll parameter, and (3) the correction is multiplicative rather than additive. These features allow our formalism to capture at first order effects which are higher order in other expansions. Although this accuracy is not necessary to compare current data with any specific model, our method has a number of applications owing to the simpler representation it provides for the connection between the power spectra and the expansion history of a general model.

Axionlike particles (ALPs) are quite generic in many scenarios for physics beyond the Standard Model. They are pseudoscalar Nambu-Goldstone bosons that appear once any global $U(1)$ symmetry is broken spontaneously. The ALPs can gain mass from various nonperturbative quantum effects, such as anomalies or instantons. ALPs can couple to the matter sector including a scalar condensate such as inflaton or moduli field via derivative interactions, which are suppressed by the axion decay constant, $f_{\chi }$. Although weakly interacting, the ALPs can be produced abundantly from the coherent oscillations of a homogeneous condensate. In this paper we will study such a scenario where the ALPs can be produced abundantly, and in some cases can even overclose the Universe via odd- and even-dimensional operators, as long as $f_{\chi }/{\mathrm{\Phi }}_{\mathrm{I}}\ll 1$, where ${\mathrm{\Phi }}_{\mathrm{I}}$ denotes the initial amplitude of the coherent oscillations of the scalar condensate, $\varphi$. We will briefly mention how such dangerous overproduction would affect dark matter and dark radiation abundances in the Universe.

We introduce a new mechanism for generating magnetic fields in the recombination era. This Harrison-like mechanism utilizes vorticity in baryons that is sourced through the Bose-Einstein condensate of axions via gravitational interactions. The magnetic fields generated are on galactic scales $\sim 10\mathrm{kpc}$ and have a magnitude of the order of $B\sim 10^{-23}\mathrm{G}$ today. The field has a greater magnitude than those generated from other mechanisms relying on second-order perturbation theory, and is sufficient to provide a seed for battery mechanisms.

We study the graviton Regge trajectory in holographic QCD as a model for high energy scattering processes dominated by soft-Pomeron exchange. This is done by considering spin $J$ fields from the closed string sector that are dual to glueball states of even spin and parity. In particular, we construct a model that governs the analytic continuation of the spin $J$ field equation to the region of real $J<2$, which includes the scattering domain of the negative Maldelstam variable $t$. The model leads to approximately linear Regge trajectories and is compatible with the measured values of 1.08 for the intercept and $0.25{\mathrm{GeV}}^{-2}$ for the slope of the soft Pomeron. The intercept of the secondary Pomeron trajectory is in the same region of the subleading trajectories, made of mesons, proposed by Donnachie and Landshoff, and should therefore be taken into account.

We study the phenomenology of the Georgi-Machacek model at next-to-leading order in QCD matched to a parton shower, using a fully automated tool chain based on MadGraph5_aMC@NLO and FeynRules. We focus on the production of the fermiophobic custodial fiveplet scalars $H_5^0$, $H_5^{\pm }$, and $H_5^{\pm \pm }$ through vector boson fusion (VBF), associated production with a vector boson ($V{H}_5$), and scalar pair production ($H_5{H}_5$). For these production mechanisms we compute next-to-leading order corrections to production rates as well as to differential distributions. Our results demonstrate that the Standard Model overall $K$-factors for such processes cannot in general be directly applied to beyond-the-Standard-Model distributions, due both to differences in the scalar electroweak charges and to the variation of the $K$-factors over the differential distributions.

Light top squarks (stops) and light higgsinos are the key features of natural supersymmetry (SUSY), where the higgsinos ${\tilde{\chi }}_1^{\pm }$ and ${\tilde{\chi }}_{1,2}^0$ are nearly degenerate and act as the missing transverse energy (${\overline{)E}}_T$) at the LHC. Besides the pair production via strong interaction, the stop can be produced via the electroweak interaction. The determination of the electroweak properties of the stop is an essential task for the LHC and future colliders. So, in this paper, we investigate the single stop (${\tilde{t}}_1$) production $pp\to {\tilde{t}}_1+{\overline{)E}}_T$ via the electroweak interaction in natural SUSY at the LHC, which gives the monotop signature $t+{\overline{)E}}_T$ from ${\tilde{t}}_1\to t{\tilde{\chi }}_{1,2}^0$ or the monobottom signature $b+{\overline{)E}}_T$ from ${\tilde{t}}_1\to b{\tilde{\chi }}_1^{+}$. We perform Monte Carlo simulations for these signatures and obtain the observations: (1) The signal $b+{\overline{)E}}_T$ has a better sensitivity than $t+{\overline{)E}}_T$ for probing natural SUSY; (2) the parameter region with a higgsino mass $100\mathrm{GeV}\lesssim \mu \lesssim 225\mathrm{GeV}$ and stop mass $m_{{\tilde{t}}_1}\lesssim 620\mathrm{GeV}$ can be probed through such single stop production with $S/\sqrt{B}>3$ and $4\%\lesssim S/B\lesssim 19\%$ at the 14 TeV LHC with an integrated luminosity of $3000{\mathrm{fb}}^{-1}$.

We consider the phenomenology of a resonance that couples to photons but not gluons, and estimate its production rate at the LHC from photon-photon fusion in elastic $pp$ scattering using the equivalent photon and narrow width approximations. The rate is sensitive only to the mass, the spin, the total width of the resonance, and its branching fraction to photons. Production cross sections of 3–6 fb at 13 TeV can be easily accommodated for a 750 GeV resonance with partial photon width of 15 GeV. This provides the minimal explanation of the reported diphoton anomaly in the early LHC Run II data.

The isospin, spin and parity dependent potential of a pair of $B$ mesons is computed using Wilson twisted mass lattice QCD with two flavors of degenerate dynamical quarks. The $B$ meson is addressed in the static-light approximation, i.e. the $b$ quarks are infinitely heavy. From the results of the $BB$ meson-meson potentials, a simple rule can be deduced stating which isospin, spin and parity combinations correspond to attractive and which to repulsive forces. We provide fits to the ground state potentials in the attractive channels and discuss the potentials in the repulsive and excited channels. The attractive channels are the most important since they can possibly lead to a bound four-quark state, i.e. a $\overline{b}\overline{b}ud$ tetraquark. Using these attractive potentials in the Schrödinger equation, we find an indication for such a tetraquark state of two static bottom antiquarks and two light $u/d$ quarks with mass extrapolated down to the physical value.

We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $\mathrm{\Lambda }$ and ${\mathrm{\Sigma }}^0$ of the CLAS and SLAC-E84 collaborations, by considering a constituent-counting rule suggested by perturbative QCD. The counting rule emerges as a scaling behavior of cross sections in hard exclusive reactions with large scattering angles, and it enables us to determine the number of elementary constituents inside hadrons. Therefore, it could be used as a new method for identifying internal constituents of exotic hadron candidates. From the analyses of the $\gamma p\to K^{+}\mathrm{\Lambda }$ and $K^{+}{\mathrm{\Sigma }}^0$ reactions, we find that the number of elementary constituents is consistent with $n_{\gamma }=1$, $n_p=3$, $n_{K^{+}}=2$, and $n_{\mathrm{\Lambda }}=n_{{\mathrm{\Sigma }}^0}=3$. Then, an analysis is made for the photoproductions of the hyperon resonances $\mathrm{\Lambda }(1405)$, $\mathrm{\Sigma }(1385{)}^0$, and $\mathrm{\Lambda }(1520)$, where $\mathrm{\Lambda }(1405)$ is considered to be a $\overline{K}N$ molecule, and hence its constituent number could be 5. However, we find that the current data are not enough to conclude the numbers of their constituents. It is necessary to investigate the higher-energy region at $\sqrt{s}>2.8\mathrm{GeV}$ experimentally beyond the energy of the available CLAS data to count the number of constituents clearly. We also mention that our results indicate energy dependence in the constituent number, especially for $\mathrm{\Lambda }(1405)$. If an excited hyperon is a mixture of three-quark and five-quark states, the energy dependence of the scaling behavior could be valuable for finding its composition and mixture.

We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos $N_{\mathrm{eff}}$ at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter $\chi$ couples more strongly to the neutrinos $\nu$ than to the photons $\gamma$ and electrons $e^{-}$, ${\mathrm{\Gamma }}_{\chi \gamma ,\chi e}\ll {\mathrm{\Gamma }}_{\chi \nu }$, or ${\mathrm{\Gamma }}_{\chi \gamma ,\chi e}\gg {\mathrm{\Gamma }}_{\chi \nu }$, the lower mass limit on the asymmetric dark matter is about 18 MeV for $N_{\mathrm{eff}}\simeq 3.0$.

We perform a joint analysis of current data from cosmology and laboratory experiments to constrain the neutrino mass parameters in the framework of Bayesian statistics, also accounting for uncertainties in nuclear modeling, relevant for neutrinoless double $\beta$ decay ($0\nu 2\beta$) searches. We find that a combination of current oscillation, cosmological, and $0\nu 2\beta$ data constrains $m_{\beta \beta }<0.045\mathrm{eV}$ ($0.014\mathrm{eV}<m_{\beta \beta }<0.066\mathrm{eV}$) at 95% C.L. for normal (inverted) hierarchy. This result is in practice dominated by the cosmological and oscillation data, so it is not affected by uncertainties related to the interpretation of $0\nu 2\beta$ data, like nuclear modeling, or the exact particle physics mechanism underlying the process. We then perform forecasts for forthcoming and next-generation experiments, and find that in the case of normal hierarchy, given a total mass of 0.1 eV, and assuming a factor-of-two uncertainty in the modeling of the relevant nuclear matrix elements, it will be possible to measure the total mass itself, the effective Majorana mass and the effective electron mass with an accuracy (at 95% C.L.) of 0.05, 0.015, 0.02 eV, respectively, as well as to be sensitive to one of the Majorana phases. This assumes that neutrinos are Majorana particles and that the mass mechanism gives the dominant contribution to $0\nu 2\beta$ decay. We argue that more precise nuclear modeling will be crucial to improve these sensitivities.

In this paper we present in more detail a construction using Wilson lines and the corresponding dual Galilean conformal field theory calculations for analytically determining holographic entanglement entropy for flat space in $2+1$ dimensions first presented in A. Bagchi, R. Basu, D. Grumiller, and M. Riegler, Phys. Rev. Lett. 114, 111602 (2015). In addition, we show how the construction using Wilson lines can be expanded to flat space higher-spin theories and determine the thermal entropy of (spin-3 charged) flat space cosmologies using this approach.

We present a new frequency-domain phenomenological model of the gravitational-wave signal from the inspiral, merger and ringdown of nonprecessing (aligned-spin) black-hole binaries. The model is calibrated to 19 hybrid effective-one-body–numerical-relativity waveforms up to mass ratios of $1:18$ and black-hole spins of $|a/m|\sim 0.85$ (0.98 for equal-mass systems). The inspiral part of the model consists of an extension of frequency-domain post-Newtonian expressions, using higher-order terms fit to the hybrids. The merger ringdown is based on a phenomenological ansatz that has been significantly improved over previous models. The model exhibits mismatches of typically less than 1% against all 19 calibration hybrids and an additional 29 verification hybrids, which provide strong evidence that, over the calibration region, the model is sufficiently accurate for all relevant gravitational-wave astronomy applications with the Advanced LIGO and Virgo detectors. Beyond the calibration region the model produces physically reasonable results, although we recommend caution in assuming that any merger-ringdown waveform model is accurate outside its calibration region. As an example, we note that an alternative nonprecessing model, SEOBNRv2 (calibrated up to spins of only 0.5 for unequal-mass systems), exhibits mismatch errors of up to 10% for high spins outside its calibration region. We conclude that waveform models would benefit most from a larger number of numerical-relativity simulations of high-aligned-spin unequal-mass binaries.

In this paper we discuss the anatomy of frequency-domain gravitational-wave signals from nonprecessing black-hole coalescences with the goal of constructing accurate phenomenological waveform models. We first present new numerical-relativity simulations for mass ratios up to 18, including spins. From a comparison of different post-Newtonian approximants with numerical-relativity data we select the uncalibrated SEOBNRv2 model as the most appropriate for the purpose of constructing hybrid post-Newtonian/numerical-relativity waveforms, and we discuss how we prepare time-domain and frequency-domain hybrid data sets. We then use our data together with results in the literature to calibrate simple explicit expressions for the final spin and radiated energy. Equipped with our prediction for the final state we then develop a simple and accurate merger-ringdown model based on modified Lorentzians in the gravitational-wave amplitude and phase, and we discuss a simple method to represent the low frequency signal augmenting the TaylorF2 post-Newtonian approximant with terms corresponding to higher orders in the post-Newtonian expansion. We finally discuss different options for modelling the small intermediate frequency regime between inspiral and merger ringdown. A complete phenomenological model based on the present work is presented in a companion paper [S. Khan et al., following paper, Phys. Rev. D 93 044007 (2016)].

We study the exclusive semileptonic $B$-meson decays $B\to K(\pi ){\ell }^{+}{\ell }^{-}$, $B\to K(\pi )\nu \overline{\nu }$, and $B\to \pi \tau \nu$, computing observables in the Standard Model using the recent lattice-QCD results for the underlying form factors from the Fermilab Lattice and MILC collaborations. These processes provide theoretically clean windows into physics beyond the Standard Model because the hadronic uncertainties are now under good control for suitably binned observables. For example, the resulting partially integrated branching fractions for $B\to \pi {\mu }^{+}{\mu }^{-}$ and $B\to K{\mu }^{+}{\mu }^{-}$ outside the charmonium resonance region are $1–2\sigma$ higher than the LHCb collaboration’s recent measurements, where the theoretical and experimental errors are commensurate. The combined tension is $1.7\sigma$. Combining the Standard-Model rates with LHCb’s measurements yields values for the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_{td}|=7.45(69)\times {10}^{-3}$, $|V_{ts}|=35.7(1.5)\times {10}^{-3}$, and $|V_{td}/V_{ts}|=0.201(20)$, which are compatible with the values obtained from neutral $B_{(s)}$-meson oscillations and have competitive uncertainties. Alternatively, taking the CKM matrix elements from unitarity, we constrain new-physics contributions at the electroweak scale. The constraints on the Wilson coefficients $\mathrm{Re}(C_9)$ and $\mathrm{Re}(C_{10})$ from $B\to \pi {\mu }^{+}{\mu }^{-}$ and $B\to K{\mu }^{+}{\mu }^{-}$ are competitive with those from $B\to K^{*}{\mu }^{+}{\mu }^{-}$, and display a $2.0\sigma$ tension with the Standard Model. Our predictions for $B\to K(\pi )\nu \overline{\nu }$ and $B\to \pi \tau \nu$ are close to the current experimental limits.

QED with strong external backgrounds that can create particles from the vacuum is well developed for the so-called $t$-electric potential steps, which are time-dependent external electric fields that are switched on and off at some time instants. However, there exist many physically interesting situations where external backgrounds do not switch off at the time infinity. E.g., these are time-independent nonuniform electric fields that are concentrated in restricted space areas. The latter backgrounds represent a kind of spatial $x$-electric potential steps for charged particles. They can also create particles from the vacuum, the Klein paradox being closely related to this process. Approaches elaborated for treating quantum effects in the $t$-electric potential steps are not directly applicable to the $x$-electric potential steps and their generalization for $x$-electric potential steps was not sufficiently developed. We believe that the present work represents a consistent solution of the latter problem. We have considered a canonical quantization of the Dirac and scalar fields with $x$-electric potential step and have found in- and out-creation and annihilation operators that allow one to have particle interpretation of the physical system under consideration. To identify in- and out-operators we have performed a detailed mathematical and physical analysis of solutions of the relativistic wave equations with an $x$-electric potential step with subsequent QFT analysis of correctness of such an identification. We elaborated a nonperturbative (in the external field) technique that allows one to calculate all characteristics of zero-order processes, such, for example, scattering, reflection, and electron-positron pair creation, without radiation corrections, and also to calculate Feynman diagrams that describe all characteristics of processes with interaction between the in-, out-particles and photons. These diagrams have formally the usual form, but contain special propagators. Expressions for these propagators in terms of in- and out-solutions are presented. We apply the elaborated approach to two popular exactly solvable cases of $x$-electric potential steps, namely, to the Sauter potential and to the Klein step.

This work is concerned with suitable choices of tetrad fields and coordinate systems for the Hamiltonian formalism of a spinning particle derived in [E. Barausse, E. Racine, and A. Buonanno, Phys. Rev. D 80, 104025 (2009)]. After demonstrating that with the originally proposed tetrad field the components of the total angular momentum are not preserved in the Schwarzschild limit, we analyze other hitherto proposed tetrad choices. Then, we introduce and thoroughly test two new tetrad fields in the horizon penetrating Kerr–Schild coordinates. Moreover, we show that for the Schwarzschild spacetime background the linearized in spin Hamiltonian corresponds to an integrable system, while for the Kerr spacetime we find chaos which suggests a nonintegrable system.