The location of the critical end point (CEP) and the isentropic trajectories in the QCD phase diagram are investigated. We use the ($2+1$) Nambu–Jona-Lasinio model with the Polyakov loop coupling for different scenarios, namely by imposing zero strange quark density, which is the case in the ultrarelativistic heavy ion collisions, and $\beta$ equilibrium. The influence of strong magnetic fields and of the vector interaction on the isentropic trajectories around the CEP is discussed. It is shown that the vector interaction and the magnetic field, having opposite effects on the first-order transition, affect the isentropic trajectories differently: as the vector interaction increases, the first-order transition becomes weaker and the isentropes become smoother; when a strong magnetic field is considered, the first-order transition is strengthened and the isentropes are pushed to higher temperatures. No focusing of isentropes in region towards the CEP is seen.

The latest and most precise top quark measurements at the LHC and Tevatron are used to establish new limits on the $Wtb$ vertex. Recent results on the measurements of the $W$-boson helicity fractions and single top quark production cross section are combined in order to establish new limits at 95% CL (confidence level). The allowed regions for these limits are presented, for the first time, in three-dimensional graphics, for both real and imaginary components of the different anomalous couplings, providing a new perspective on the impact of the combination of different physics observables. These results are also combined with the prospected future measurement of the single top quark production cross section and $W$-boson helicity fractions at the LHC.

The first study is presented of $CP$ violation with an amplitude analysis of the Dalitz plot of $B^0\to D{K}^{+}{\pi }^{-}$ decays, with $D\to K^{+}{\pi }^{-}$, $K^{+}{K}^{-}$, and ${\pi }^{+}{\pi }^{-}$. The analysis is based on a data sample corresponding to $3.0{\mathrm{fb}}^{-1}$ of $pp$ collisions collected with the LHCb detector. No significant $CP$ violation effect is seen, and constraints are placed on the angle $\gamma$ of the unitarity triangle formed from elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated with the $B^0\to D{K}^{*}(892{)}^0$ decay are determined for the first time. These measurements can be used to improve the sensitivity to $\gamma$ of existing and future studies of the $B^0\to D{K}^{*}(892{)}^0$ decay.

The process $\gamma \gamma \to p\overline{p}{K}^{+}{K}^{-}$ and its intermediate processes are measured for the first time using a $980{\mathrm{fb}}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The production of $p\overline{p}{K}^{+}{K}^{-}$ and a $\mathrm{\Lambda }(1520{)}^0$ $(\overline{\mathrm{\Lambda }}(1520{)}^0)$ signal in the $p{K}^{-}$ ($\overline{p}{K}^{+}$) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near $1540\mathrm{MeV}/c^2$, denoted as $\mathrm{\Theta }(1540{)}^0$ ($\overline{\mathrm{\Theta }}(1540{)}^0$) or $\mathrm{\Theta }(1540{)}^{++}$ ($\mathrm{\Theta }(1540{)}^{--}$), is seen in the $p{K}^{-}$ ($\overline{p}{K}^{+}$) or $p{K}^{+}$ ($\overline{p}{K}^{-}$) invariant mass spectra. Cross sections for $\gamma \gamma \to p\overline{p}{K}^{+}{K}^{-}$, $\mathrm{\Lambda }(1520{)}^0\overline{p}{K}^{+}+\mathrm{c}.\mathrm{c}.$ and the products $\sigma (\gamma \gamma \to \mathrm{\Theta }(1540{)}^0\overline{p}{K}^{+}+\mathrm{c}.\mathrm{c}.)\mathcal{B}(\mathrm{\Theta }(1540{)}^0\to p{K}^{-})$ and $\sigma (\gamma \gamma \to \mathrm{\Theta }(1540{)}^{++}\overline{p}{K}^{-}+\mathrm{c}.\mathrm{c}.)\mathcal{B}(\mathrm{\Theta }(1540{)}^{++}\to p{K}^{+})$ are measured. We also determine upper limits on the products of the ${\chi }_{c0}$ and ${\chi }_{c2}$ two-photon decay widths and their branching fractions to $p\overline{p}{K}^{+}{K}^{-}$ at the 90% credibility level.

Vacuum stability in the Standard Model is problematic as the Higgs quartic self-coupling runs negative at a renormalization scale of about ${10}^{10}\mathrm{GeV}$. We consider a nonsupersymmetric SO(10) grand unification model for which gauge coupling unification is made possible through an intermediate scale gauge group, $G_{\mathrm{int}}=\mathrm{SU}(3{)}_C\otimes \mathrm{SU}(2{)}_L\otimes \mathrm{SU}(2{)}_R\otimes \mathrm{U}(1{)}_{B-L}$. $G_{\mathrm{int}}$ is broken by the vacuum expectation value of a $\mathbf{126}$ of SO(10) which not only provides for neutrino masses through the seesaw mechanism but also preserves a discrete ${\mathbb{Z}}_2$ that can account for the stability of a dark matter candidate, here taken to be the Standard Model singlet component of a bosonic $\mathbf{16}$. We show that in addition to these features the model insures the positivity of the Higgs quartic coupling through its interactions to the dark matter multiplet and $\mathbf{126}$. We also show that the Higgs mass squared runs negative, triggering electroweak symmetry breaking. Thus, the vacuum stability is achieved along with radiative electroweak symmetry breaking and captures two more important elements of supersymmetric models without low-energy supersymmetry. The conditions for perturbativity of quartic couplings and for radiative electroweak symmetry breaking lead to tight upper and lower limits on the dark matter mass, respectively, and this dark matter mass region (1.35–2 TeV) can be probed in future direct detection experiments.

We revisit a class of $SU(5)$ supersymmetric grand unified theory (SUSY GUT) models which arise in the context of the spectral cover with Klein Group monodromy $V_4=Z_2\times Z_2$. We examine the polynomials of the corresponding factorized spectral cover and discuss the constraints imposed on their coefficients for the transitive and nontransitive realization of this monodromy. We show that $Z_2$ matter parities can be realized via new geometric symmetries respected by the spectral cover.

The subvacuum phenomena, induced by the squeezed vacuum of the strongly coupled quantum critical fields with a dynamical scaling $z$, are explored by a probe particle. The holographic description corresponds to a string moving in ($4+1$)-dimensional Lifshitz geometry with gravitational wave perturbations. The dynamics of the particle can be realized from the motion of the endpoint of the string at the boundary. We then examine the particle’s velocity dispersion, influenced by the squeezed vacuum states of strongly coupled quantum critical fields. With appropriate choices of squeezing parameters, the velocity dispersion is found to be smaller than the value caused by the normal vacuum fluctuations of the fields. This leads to the subvacuum effect. We find that the large coupling constant of the quantum fields tends to counteract the effect in the reduction of velocity dispersion, though this phenomenon is in principle observable. The effect of the squeezed vacuum on the decoherence dynamics of a quantum particle is also investigated. Coherence loss can be shown to be less severe in certain squeezed vacuums than in normal vacuum. This recovery of coherence is understood as recoherence, another manifestation of the subvacuum phenomena. We make some estimates of the degree of recoherence and find that, contrary to the velocity dispersion case, the recoherence effect is enhanced by the large coupling constant. Finally we compare the findings in our earlier works when the particle is influenced by a weakly coupled relativistic field with the dynamical scaling $z=1$.

Nonlinear Maxwell equations are written up to the third-power deviations from a constant-field background, valid within any local nonlinear electrodynamics including QED with a Euler-Heisenberg (EH) effective Lagrangian. The linear electric response to an imposed static finite-sized charge is found in the vacuum filled by an arbitrary combination of constant and homogeneous electric and magnetic fields. The modified Coulomb field and corrections to the total charge and to the charge density are given in terms of derivatives of the effective Lagrangian with respect to the field invariants. These are specialized for the EH Lagrangian.

There has been considerable interest in applying the gauge-gravity duality to condensed matter theories with particular attention being devoted to gravity duals (Lifshitz spacetimes) of theories that exhibit anisotropic scaling. In this context, black hole solutions with Lifshitz asymptotics have also been constructed, focused on incorporating finite temperature effects. The goal here is to look at quantum polarization effects in these spacetimes and, to this aim, we develop a way to compute the coincidence limit of the Green’s function for massive, nonminimally coupled scalar fields, adapting to the present situation the analysis developed for the case of asymptotically anti–de Sitter black holes. The basics are similar to previous calculations; however, in the Lifshitz case, one needs to extend the previous results to include a more general form for the metric and dependence on the dynamical exponent. All formulas are shown to reduce to the anti–de Sitter (AdS) case studied before once the value of the dynamical exponent is set to unity and the metric functions are accordingly chosen. The analytical results we present are general and can be applied to a variety of cases, in fact, to all spherically symmetric Lifshitz black hole solutions. We also implement the numerical analysis choosing some known Lifshitz black hole solutions as illustration.

We explore how a recently developed analytical black-hole binary spacetime can be extended using numerical simulations to go beyond the slow-inspiral phase. The analytic spacetime solves the Einstein field equations approximately, with the approximation error becoming progressively smaller the more separated the binary. To continue the spacetime beyond the slow-inspiral phase, we need to transition. Such a transition was previously explored at smaller separations. Here, we perform this transition at a separation of $D=20M$ (large enough that the analytical metric is expected to be accurate), and evolve for six orbits. We find that small constraint violations can have large dynamical effects, but these can be removed by using a constraint-damping system like the conformal covariant formulation of the Z4 system. We find agreement between the subsequent numerical spacetime and the predictions of post-Newtonian theory for the waveform and inspiral rate that is within the post-Newtonian truncation error.

$CP$ violation, which is crucial for producing the baryon asymmetry of the Universe, is enhanced in particle-antiparticle oscillations. We study particle-antiparticle oscillations [of a particle with mass $O(100\mathrm{GeV})$] with $CP$ violation in the early Universe in the presence of interactions with $O(\mathrm{ab}\text{−}\mathrm{fb})$ cross sections. We show that if baryon-number-violating interactions exist, a baryon asymmetry can be produced via out-of-equilibrium decays of oscillating particles. As a concrete example we study a $U(1{)}_R$-symmetric, $R$-parity-violating supersymmetry model with pseudo-Dirac gauginos, which undergo particle-antiparticle oscillations. Taking bino to be the lightest $U(1{)}_R$-symmetric particle, and assuming it decays via baryon-number-violating interactions, we show that bino-antibino oscillations can produce the baryon asymmetry of the Universe.

In this paper, we provide a systematic investigation of high-order primordial perturbations with nonlinear dispersion relations due to quantum gravitational effects in the framework of uniform asymptotic approximations. Because of these effects, the equation of motion of the mode function in general has multiple turning points. After obtaining analytically approximated solutions to any order in different regions, associated with different types of turning points, we match them to the third one. To this order the errors are less than 0.15%. General expressions of the power spectra of the primordial tensor and scalar perturbations are derived explicitly. We also investigate effects of backreactions of the quantum gravitational corrections, and make sure that inflation lasts long enough in order to solve the underlying problems, such as flatness, horizon, and monopole. Then we study various features of the spectra that are observationally relevant. In particular, under a moderate assumption about the energy scale of the underlying theory of quantum gravity, we have shown that the quantum gravitational effects may alter significantly the ratio between the tensor and scalar power spectra, thereby providing a natural mechanism to alleviate the tension between observations and certain inflationary models, including the one with a quadratic potential.

We investigate the influence of cosmological constant $\mathrm{\Lambda }$ on gravitational lensing. By the method of an elliptic integral, we give out the solution to the null geodesic equation in the Reissner–Nordstrom–de Sitter spacetime. The deflection angle of light is obtained by studying the intrinsic geometry of the spatial equatorial plane in the Reissner–Nordstrom–de Sitter spacetime. By applying the expansion of elliptic integrals, we find the deflection angle in the weak field limit and in the strong field limit, respectively. We find the angular position and magnification of images and discuss its behavior under changed $\mathrm{\Lambda }$. At last, we give out the higher-order term in the strong field limit.

The Comment against our work [S. Mondal and S. K. Rai, Phys. Rev. D 93, 011702 (2016).] is based on a presumptive and incorrectly chosen large value of “charge-flip” probability. We address the concerns of the author and show why the values chosen and the estimates of the background cross section given in the Comment become irrelevant when folded in with expected numbers for the efficiency provided by an analysis done by the CMS Collaboration for a heavy Majorana neutrino search after proper event selection criteria are set for the final states.

Reference [S. Mondal and S. K. Rai, Phys. Rev. D 93, 011702 (2016).] recently argued that the projected Large Hadron Electron Collider (LHeC) presents a unique opportunity to discover a left-right symmetry since the LHeC has availability for polarized electrons. In particular, the authors apply some basic $p_T$ cuts on the jets and claim that the on-shell production of right-handed neutrinos at the LHeC, which violates lepton number in two units, has practically no standard model background and, therefore, that the right-handed nature of $W_R$ interactions that are intrinsic to left-right symmetric models can be confirmed by using colliding beams consisting of an 80% polarized electron and a 7 TeV proton. In this Comment, we show that their findings, as presented, have vastly underestimated the SM background which prevents a Left-Right symmetry signal from being seen at the LHeC.

We propose a minimal vectorlike leptonic dark matter (DM) with renormalizable interaction in a beyond-the-Standard-Model (SM) scenario, in which the SM is augmented with a vectorlike doublet and a singlet lepton. The additional fermions are odd under a discrete $Z_2$ symmetry, while the rest of the SM particles are singlets, thus providing stability to the DM. In this scenario, we show that the DM emerges as an admixture of the neutral component of the vectorlike doublet and the singlet leptons. The singlet-doublet mixing ($\sin \theta$) plays a crucial role in yielding the correct relic density as well as in obtaining null direct DM search results through an interplay of interactions via $Z$ and Higgs mediation. The mixing is also strongly constrained from the invisible $Z$ and Higgs decay width. We found that the correct relic abundance of DM can be obtained in a large region of parameter space for a DM mass larger than $M_Z/2$ and $\sin \theta \lesssim 0.1$. The details of model phenomenology with collider signatures at the Large Hadron Collider (LHC) are discussed. In particular, we show that for $\sin \theta \lesssim 0.01$, the charged companion of the DM can give rise to an observable displaced vertex signature, marking a significant departure from other fermionic DM scenarios, while keeping the relic abundance intact.

We consider the observable effects of $CP$-violating anomalous $ZZh$ interaction arising from gauge-invariant dimension-six operators at the Large Hadron Collider (LHC), with the purpose of distinguishing them from not only the standard model effects but also those of $CP$-even anomalous interactions of a similar nature. The postulation of a gauge-invariant origin makes various couplings of this kind interrelated. The updated constraints from the LHC as well as limits from neutron and electron dipole moments are used in selecting the benchmark interaction strengths. We use some asymmetry parameters that have no contribution from standard or $CP$-even anomalous interactions. Parton showering and detector-level simulation are included to make our analysis as realistic as possible. On the whole, we conclude that gauge-invariant interaction of strength $\ge 40/{\mathrm{TeV}}^2$ can be successfully isolated using integrated luminosities in the $1.5–3.0{\mathrm{ab}}^{-1}$ range.

We consider the minimal ${\mathrm{U}(1)}^{\prime }$ extension of the standard model (SM) with the classically conformal invariance, where an anomaly-free ${\mathrm{U}(1)}^{\prime }$ gauge symmetry is introduced along with three generations of right-handed neutrinos and a ${\mathrm{U}(1)}^{\prime }$ Higgs field. Since the classically conformal symmetry forbids all dimensional parameters in the model, the ${\mathrm{U}(1)}^{\prime }$ gauge symmetry is broken by the Coleman-Weinberg mechanism, generating the mass terms of the ${\mathrm{U}(1)}^{\prime }$ gauge boson ($Z^{\prime }$ boson) and the right-handed neutrinos. Through a mixing quartic coupling between the ${\mathrm{U}(1)}^{\prime }$ Higgs field and the SM Higgs doublet field, the radiative ${\mathrm{U}(1)}^{\prime }$ gauge symmetry breaking also triggers the breaking of the electroweak symmetry. In this model context, we first investigate the electroweak vacuum instability problem in the SM. Employing the renormalization group equations at the two-loop level and the central values for the world average masses of the top quark ($m_t=173.34\mathrm{GeV}$) and the Higgs boson ($m_h=125.09\mathrm{GeV}$), we perform parameter scans to identify the parameter region for resolving the electroweak vacuum instability problem. Next we interpret the recent ATLAS and CMS search limits at the LHC Run-2 for the sequential $Z^{\prime }$ boson to constrain the parameter region in our model. Combining the constraints from the electroweak vacuum stability and the LHC Run-2 results, we find a bound on the $Z^{\prime }$ boson mass as $m_{Z^{\prime }}\gtrsim 3.5\mathrm{TeV}$. We also calculate self-energy corrections to the SM Higgs doublet field through the heavy states, the right-handed neutrinos and the $Z^{\prime }$ boson, and find the naturalness bound as $m_{Z^{\prime }}\lesssim 7\mathrm{TeV}$, in order to reproduce the right electroweak scale for the fine-tuning level better than 10%. The resultant mass range of $3.5\mathrm{TeV}\lesssim m_{Z^{\prime }}\lesssim 7\mathrm{TeV}$ will be explored at the LHC Run-2 in the near future.

Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply virtual Compton scattering and deeply virtual meson production with lepton beam. A complementary probe with hadron beam is the exclusive pion-induced Drell-Yan process. In this paper, we discuss recent theoretical advances on describing this process in terms of nucleon GPDs and pion distribution amplitudes. Furthermore, we address the feasibility of measuring the exclusive pion-induced Drell-Yan process ${\pi }^{-}p\to {\mu }^{+}{\mu }^{-}n$ via a spectrometer at the High Momentum Beamline being constructed at J-PARC in Japan. Realization of such measurement at J-PARC will provide a new test of perturbative QCD descriptions of a novel class of hard exclusive reactions. It will also offer the possibility of experimentally accessing nucleon GPDs at large timelike virtuality.

A symmetry-preserving truncation of the two-body bound state problem in relativistic quantum field theory is used to compute the leading-twist parton distribution amplitudes (PDAs) for the first radial excitations of the $\pi$ and $K$ mesons. In common with ground states in these channels, the PDAs are found to be dilated with respect to the relevant conformal-limit form and skewed toward the heavier valence quark in asymmetric systems. In addition, the PDAs of radially excited pseudoscalar mesons are not positive definite, owing to the fact that dynamical chiral symmetry breaking (DCSB) forces the leptonic decay constant of such states to vanish in the chiral limit. These results highlight that DCSB is expressed visibly in every pseudoscalar meson constituted from light quarks. Hence, so long as its impact is empirically evident in the pseudoscalar members of a given spectrum level, it is unlikely that chiral symmetry is restored in any of the hadrons that populate this level.