In the framework of weakly coupled potential nonrelativistic QCD, we derive, first, an analytical expression for the chromopolarizability of $1S$ bottomonium states in agreement with previous determinations. Then we use the QCD trace anomaly to obtain the two-pion production amplitude for the chromopolarizability operator and match the result to a chiral effective field theory with $1S$ bottomonium states and pions as degrees of freedom. In this chiral effective field theory we compute some long-range properties of the $1S$ bottomonium generated by the pion coupling such as the leading chiral logarithm to the $1S$ bottomonium mass and the van der Waals potential between two $1S$ bottomonium states. Both results improve on previously known expressions.

A system presenting fractal structure in its thermodynamical functions is introduced, and it is shown that Tsallis statistics is the correct framework for describing the thermodynamical aspects of such a fractal. Its Haussdorf dimension and its Lipshitz-Hölder exponent are determined in terms of the entropic index $q$. The connections with the intermittency in experimental data are discussed. The thermodynamical aspects of the thermofractal is related to the microscopic interaction of its components through the $S$-matrix.

This paper examines detection prospects and constraints on the chromomagnetic dipole operator for the bottom quark. This operator has a flavor, chirality and Lorentz structure that is distinct from other dimension-6 operators considered in Higgs coupling studies. Its nonstandard Lorentz structure results in boosted $b\overline{b}h$ events, providing a rate-independent signal of new physics. To date, we find this operator is unconstrained by $pp\to h+\mathrm{jets}$ and $pp\to \overline{b}b$ searches: for order-1 couplings the permitted cutoff $\mathrm{\Lambda }$ for this operator can be as low as $\mathrm{\Lambda }\sim 1\mathrm{TeV}$. We show how to improve this bound with collider cuts that allow a $b$-tagged Higgs-plus-dijet search in the Higgs-to-diphoton decay channel to exclude cutoffs as high as $\sim 6\mathrm{TeV}$ at $2\sigma$ with $3{\mathrm{ab}}^{-1}$ of luminosity at the 14 TeV LHC. Cuts on the $p_T$ of the Higgs are key to this search, because the chromomagnetic dipole yields a nonstandard fraction of boosted Higgses.

We describe a measurement of the ratio of the cross sections times branching fractions of the $B_c^{+}$ meson in the decay mode $B_c^{+}\to J/\psi {\mu }^{+}\nu$ to the $B^{+}$ meson in the decay mode $B^{+}\to J/\psi K^{+}$ in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96\mathrm{TeV}$. The measurement is based on the complete CDF Run II data set, which comes from an integrated luminosity of $8.7{\mathrm{fb}}^{-1}$. The ratio of the production cross sections times branching fractions for $B_c^{+}$ and $B^{+}$ mesons with momentum transverse to the beam greater than $6\mathrm{GeV}/c$ and rapidity magnitude smaller than 0.6 is $0.211\pm 0.012{(\mathrm{stat})}_{-0.020}^{+0.021}(\mathrm{syst})$. Using the known $B^{+}\to J/\psi K^{+}$ branching fraction, the known $B^{+}$ production cross section, and a selection of the predicted $B_c^{+}\to J/\psi {\mu }^{+}\nu$ branching fractions, the range for the total $B_c^{+}$ production cross section is estimated.

We study transitions of hadronic matter (HM) to three-flavor quark matter (3QM), regarding the conversion processes as combustion and describing them hydrodynamically. Under the assumption that HM is metastable with their free energies being larger than those of 3QM but smaller than those of two-flavor quark matter, we consider in this paper the conversion induced by diffusions of the seed 3QM. This is a sequel to our previous paper, in which the shock-induced conversion was studied in the same framework. We not only pay attention to the jump condition on both sides of the conversion front, but the structures inside the front are also considered by taking into account what happens during the conversion processes on the time scale of weak interactions. We employ for HM Shen’s equation of state (EOS), which is based on the relativistic mean field theory, and the bag model-based EOS for quark matter just as in the previous paper. We demonstrated in that paper that in this combination of EOSs, the combustion will occur for a wide range of the bag constant and strong coupling constant in the so-called endothermic regime, in which the Hugoniot curve for combustion runs below the initial state. Elucidating the essential features of the diffusion-induced conversion both in the exothermic and endothermic regimes first by a toy model, we then analyze more realistic models. We find that weak deflagration nearly always occurs and that weak detonation is possible only when the diffusion constant is (unrealistically) large and the critical strange fraction is small. The velocities of the conversion front are $\sim {10}^3–{10}^7\mathrm{cm}/\mathrm{s}$ depending on the initial temperature and density as well as the parameters in the quark matter EOS and become particularly small when the final state is in the mixed phase. Finally we study linear stability of the laminar weak-deflagration front and find that it is unstable in the exothermic regime (Darrius-Landau instability) but stable in the endothermic regime, which is quite contrary to the ordinary combustions.

We study transitions of hadronic matter (HM) to three-flavor quark matter (3QM) locally, regarding the conversion processes as combustion and describing them hydrodynamically. Not only the jump condition on both sides of the conversion front but the structures inside the front are also considered by taking into account what happens during the conversion processes on the time scale of weak interactions as well as equations of state (EOSs) in the mixed phase. Under the assumption that HM is metastable with their free energies being larger than those of 3QM but smaller than those of two-flavor quark matter (2QM), we consider the transition via 2QM triggered by a rapid density rise in a shock wave. Based on the results, we discuss which combustion modes (strong/weak detonation) may be realized. HM is described by an EOS based on the relativistic mean field theory, and 2QMs and 3QMs are approximated by the MIT bag model. We demonstrate for a wide range of the bag constant and strong coupling constant in this combination of EOSs that the combustion may occur in the so-called endothermic regime, in which the Hugoniot curve for combustion runs below the one for the shock wave in the $p-V$ plane and which has no terrestrial counterpart. Elucidating the essential features in this scenario first by a toy model, we then analyze more realistic models. We find that strong detonation always occurs. Depending on the EOS of quark matter as well as the density of HM and the Mach number of the detonation front, deconfinement from HM to 2QM is either completed or not completed in the shock wave. In the latter case, which is more likely if the EOS of quark matter ensures that deconfinement occurs above the nuclear saturation density and that the maximum mass of cold quark stars is larger than $2M_{\odot }$, the conversion continues further via the mixing state of HM and 3QM on the time scale of weak interactions.

In the alignment limit of a multidoublet Higgs sector, one of the Higgs mass eigenstates aligns in field space with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider $CP$-conserving two-Higgs-doublet models (2HDMs) of type I and type II near the alignment limit in which the heavier of the two $CP$-even Higgs bosons, $H$, is the SM-like state observed with a mass of 125 GeV, and the couplings of $H$ to gauge bosons approach those of the SM. We review the theoretical structure and analyze the phenomenological implications of this particular realization of the alignment limit, where decoupling of the extra states cannot occur given that the lighter $CP$-even state $h$ must, by definition, have a mass below 125 GeV. For the numerical analysis, we perform scans of the 2HDM parameter space employing the software packages 2hdmc and lilith, taking into account all relevant pre-LHC constraints, constraints from the measurements of the 125 GeV Higgs signal at the LHC, as well as the most recent limits coming from searches for other Higgs-like states. Implications for Run 2 at the LHC, including expectations for observing the other scalar states, are also discussed.

We compute fragmentation corrections to hadroproduction of the quarkonium states $J/\psi$, ${\chi }_{cJ}$, and $\psi (2S)$ at leading power in $m_c^2/p_T^2$, where $m_c$ is the charm-quark mass and $p_T$ is the quarkonium transverse momentum. The computation is carried out in the framework of nonrelativistic QCD. We include corrections to the parton-production cross sections through next-to-leading order in the strong coupling ${\alpha }_s$ and corrections to the fragmentation functions through second order in ${\alpha }_s$. We also sum leading logarithms of $p_T^2/m_c^2$ to all orders in perturbation theory. We find that, when we combine these leading-power fragmentation corrections with fixed-order calculations through next-to-leading order in ${\alpha }_s$, we are able to obtain good fits for $p_T\ge 10\mathrm{GeV}$ to hadroproduction cross sections that were measured at the Tevatron and the LHC. Using values for the nonperturbative long-distance matrix elements that we extract from the cross-section fits, we make predictions for the polarizations of the quarkonium states. We obtain good agreement with measurements of the polarizations, with the exception of the CDF Run II measurement of the prompt $J/\psi$ polarization, for which the agreement is only fair. In the predictions for the prompt-$J/\psi$ cross sections and polarizations, we take into account feeddown from the ${\chi }_{cJ}$ and $\psi (2S)$ states.

We introduce a prescription to compute the entanglement entropy of Galilean conformal field theories by combining gravitational anomalies and an İnönü-Wigner contraction. We find that our expression for the entanglement entropy in the thermal limit reproduces the Cardy formula for Galilean conformal field theories. Using this proposal, we calculate the entanglement entropy for a class of Galilean conformal field theories, which are believed to be dual to three-dimensional flat-space cosmological solutions. These geometries describe expanding (contracting) universes and can be viewed as the flat-space limit of rotating Bañados-Teitelboim-Zanelli black holes. We show that our finding reduces, in the appropriate limits, to the results discussed in the literature and provide interpretations for the previously unexplored regimes, such as flat-space chiral gravity.

Radiation reaction remains one of the most fascinating open questions in electrodynamics. The development of multi-petawatt laser facilities capable of reaching extreme intensities has lent this topic a new urgency, and it is now more important than ever to properly understand it. Two models of radiation reaction, due to Landau and Lifshitz and due to Sokolov, have gained prominence, but there has been little work exploring the relation between the two. We show that in the Sokolov theory, electromagnetic fields induce a Lorentz transformation between momentum and velocity, which eliminates some of the counterintuitive results of Landau-Lifshitz. In particular, the Lorentz boost in a constant electric field causes the particle to lose electrostatic potential energy more rapidly than it otherwise would, explaining the longstanding mystery of how an electron can radiate while experiencing no radiation reaction force. These ideas are illustrated in examples of relevance to astrophysics and laser-particle interactions, where radiation reaction effects are particularly prominent.

Using a quantum field theory approach, we consider particle scattering and vacuum instability in the so-called $L$-constant electric field, which is a constant electric field confined between two capacitor plates separated by a finite distance $L$. We obtain and analyze special sets of stationary solutions of the Dirac and Klein-Gordon equations with the $L$-constant electric field. Then, we represent probabilities of particle scattering and characteristics of the vacuum instability (related to pair creation) in terms of the introduced solutions. From exact formulas, we derive asymptotic expressions for the differential mean numbers, for the total mean number of created particles, and for the vacuum-to-vacuum transition probability. Using the equivalence principle, we demonstrate that the distributions of particles created by the $L$-constant electric field and the gravitational field of a black hole have a similar thermal structure.

We provide a general formulation for calculating conserved charges for solutions to generally covariant gravitational theories with possibly other internal gauge symmetries, in any dimensions and with generic asymptotic behaviors. These solutions are generically specified by a number of exact (continuous, global) symmetries and some parameters. We define “parametric variations” as field perturbations generated by variations of the solution parameters. Employing the covariant phase space method, we establish that the set of these solutions (up to pure gauge transformations) form a phase space, the solution phase space, and that the tangent space of this phase space includes the parametric variations. We then compute conserved charge variations associated with the exact symmetries of the family of solutions, caused by parametric variations. Integrating the charge variations over a path in the solution phase space, we define the conserved charges. In particular, we revisit “black hole entropy as a conserved charge” and the derivation of the first law of black hole thermodynamics. We show that the solution phase space setting enables us to define black hole entropy by an integration over any compact, codminesion-2, smooth spacelike surface encircling the hole, as well as to a natural generalization of Wald and Iyer-Wald analysis to cases involving gauge fields.

We derive a generalized deviation equation—analogous to the well-known geodesic deviation equation—for test bodies in general relativity. Our result encompasses and generalizes previous extensions of the standard geodesic deviation equation. We show how the standard as well as a generalized deviation equation can be used to measure the curvature of spacetime by means of a set of test bodies. In particular, we provide exact solutions for the curvature by using the standard deviation equation as well as its next order generalization.

We show universality of isothermal fluid spheres in pure Lovelock gravity where the equation of motion has only one $N$th order term coming from the corresponding Lovelock polynomial action of degree $N$. Isothermality is characterized by the equation of state, $p=\alpha \rho$ and the property, $\rho \sim 1/r^{2N}$. Then the solution describing isothermal spheres, which exist only for the pure Lovelock equation, is of the same form for the general Lovelock degree $N$ in all dimensions $d\ge 2N+2$. We further prove that the necessary and sufficient condition for the isothermal sphere is that its metric is conformal to the massless global monopole or the solid angle deficit metric, and this feature is also universal.

Gravitational waves from coalescing binary black holes encode the evolution of their spins prior to merger. In the post-Newtonian regime and on the precession time scale, this evolution has one of three morphologies, with the spins either librating around one of two fixed points (“resonances”) or circulating freely. In this paper we perform full parameter estimation on resonant binaries with fixed masses and spin magnitudes, changing three parameters: a conserved “projected effective spin” $\xi$ and resonant family $\mathrm{\Delta }\mathrm{\Phi }=0,\pi$ (which uniquely label the source); the inclination ${\theta }_{JN}$ of the binary’s total angular momentum with respect to the line of sight (which determines the strength of precessional effects in the waveform); and the signal amplitude. We demonstrate that resonances can be distinguished for a wide range of binaries, except for highly symmetric configurations where precessional effects are suppressed. Motivated by new insight into double-spin evolution, we introduce new variables to characterize precessing black hole binaries which naturally reflects the time scale separation of the system and therefore better encode the dynamical information carried by gravitational waves.

The matter bounce scenario allows for a sizable parameter space where cosmological fluctuations originally exited the Hubble radius when the background energy density was small. In this scenario and its extended versions, the low energy degrees of freedom are likely responsible for the statistical properties of the cosmic microwave background power spectrum at large length scales. An interesting consequence is that these modes might be observable only at relatively late times. Therefore low redshift observations could provide evidence for, or even falsify, various bouncing models. We provide an example where a recently hinted potential deviation from $\mathrm{\Lambda }$-cold-dark-matter cosmology results from a dark matter and dark energy interaction. The same interaction allows matter bounce models to generate a red tilt for the primordial curvature perturbations in corroboration with cosmic microwave background experiments.

In this paper, we consider a charged massive fermionic quantum field in the spacetime of an idealized cosmic string, in the presence of a magnetic field confined in a cylindrical tube of finite radius. Three distinct configurations for the magnetic field are taken into account: (i) a cylindrical shell of radius $a$, (ii) a magnetic field proportional to $1/r$, and (iii) a constant magnetic field. In these three cases, the axis of the infinitely long tube of radius $a$ coincides with the cosmic string. Our main objective is to analyze the induced vacuum fermionic current densities outside the tube. In order to do that, we explicitly construct the wave functions inside and outside the tube for each case. Having the complete set of normalized wave functions, we use the summation method to develop our analysis. We show that, in the region outside the tube, the induced currents are decomposed into parts corresponding to a zero-thickness magnetic flux in addition to core-induced contributions. The latter presents a specific form depending on the magnetic field configuration considered. We also see that the only nonvanishing component of fermionic current corresponds to the azimuthal one. The zero-thickness contribution depends only on the fractional part of the ration of the magnetic flux inside the tube by the quantum one. As to the core-induced contribution, it depends on the total magnetic flux inside the tube and, consequently, it is not, in general, a periodic function of the flux.

Experimental studies of the quark-gluon plasma (QGP) focus on two, in practice distinct, regimes: one in which the baryonic chemical potential ${\mu }_B$ is essentially zero, the other in which it is of the same order of magnitude as the temperature. The cosmic QGP which dominates the early universe after reheating is normally assumed to be of the first kind, but recently it has been suggested that it might well be of the second: this is the case in the theory of “little inflation.” If that is so, then it becomes a pressing issue to fix the trajectory of the Universe, as it cools, through the quark matter phase diagram: in particular, one wishes to know where in that diagram the plasma epoch ends, so that the initial conditions of the hadronic epoch can be determined. Here we combine various tools from strongly coupled QGP theory (the latest lattice results, together with gauge-gravity duality) in order to constrain that trajectory, assuming that little inflation did occur.

Constrained flavor violation (CFV) is a recent proposal for predicting the down-quark Yukawa matrix in terms of those for up quarks and charged leptons. We study the viability of CFV with respect to its predictions for the lepton mass ratios, showing that this remains a challenge, and suggest some possible means for improving this shortcoming. We then extend CFV to include neutrinos, and show that it leads to interesting predictions for hierachical heavy neutrinos, and leptogenesis dominated by decays of the second heaviest one (“N2 leptogenesis”), as well as the possibility of low-scale leptoquark-mediated exotic decays.

We present a phenomenological study of triple-Higgs production in which we estimate the prospects for measuring the form of the Higgs potential at future circular collider projects. We analyze proton-proton collisions at a center-of-mass energy of 100 TeV and focus on two different signatures in which the final state is made of four $b$ jets and either a pair of photons or a pair of tau leptons. We study the resulting sensitivity on the Higgs cubic and quartic self-interactions and investigate how it depends on the $b$-tagging, tau-tagging and photon-resolution performances of detectors that could be designed for these future machines. We then discuss possible luminosity goals for future 100 TeV collider projects that would allow for a measurement of the Higgs potential and its possible departures from the Standard Model expectation.