We investigate the possibility that quarks and leptons are unified at a low energy scale much smaller than the grand unified scale. A simple theory for quark-lepton unification based on the gauge group $\mathrm{SU}(4{)}_C\otimes \mathrm{SU}(2{)}_L\otimes \mathrm{U}(1{)}_R$ is proposed. This theory predicts the existence of scalar leptoquarks which could be produced at the Large Hadron Collider. In order to have light neutrinos without fine-tuning, their masses are generated through the inverse seesaw mechanism.

We have examined the existence of the $N^{*}(1685)$ resonance, which is recently listed by the Particle Data Group as a one-star nucleon resonance, by using a covariant isobar model for kaon photoproduction and assuming that the resonance has $J^p=1/2^{+}$, in accordance with our previous finding. After the inclusion of this resonance, the changes in the total ${\chi }^2$ show two clear minima at $M_{N^{*}}=1650$ and 1696 MeV, which correspond to two different resonance states. The former corresponds to the narrow nucleon resonance found in our previous investigation, whereas the latter corresponds to a new resonance found as we increase the resonance width. From the latter we derive the mass and width relation of the $N^{*}(1685)$ resonance. We observe that the properties of both the $N^{*}(1685)$ and $N^{*}(1710)P_{11}$ resonances are strongly correlated. Although the best fit of the present work yields $M_{N^{*}}=1696\mathrm{MeV}$ and ${\Gamma }_{N^{*}}=76\mathrm{MeV}$, the apparently small $N^{*}(1710)P_{11}$ coupling constant to the $K^{+}\Lambda$ channel found in previous investigations suggests that ${\Gamma }_{N^{*}}\lesssim 35\mathrm{MeV}$, which, according to the mass and width relation, corresponds to $M_{N^{*}}\lesssim 1680\mathrm{MeV}$.

Several direct detection experiments have reported positive signals consistent with a dark matter particle with a mass of approximately 7–9 GeV and a spin-independent scattering cross section of $2.5–4.8\times {10}^{-41}{\mathrm{cm}}^2$. These results do not rise to the level of discovery, but assuming that they are due to dark matter, some questions about the underlying physics can already be addressed. In this paper, I apply the effective operator formalism for dark matter Standard Model interactions to the results of the CoGeNT and CDMS silicon target experiments. I demonstrate that only one set of flavor-blind effective operators between dark matter and quarks can be consistent with the reported results in all energy regimes of interest, namely thermal freeze-out, nuclear scattering, indirect detection, and TeV-scale colliders. This set of operators implies large couplings of dark matter with heavy quarks. The alternative implies either that the new physics has nontrivial flavor structure, that the effective formalism is not applicable and so contains new states in the spectrum accessible at the LHC, or has large annihilation channels (possibly via effective operators) into noncolored Standard Model particles.

In this paper various constraints for the parameter spaces of two variants of the two-Higgs-doublet model with a ${\mathbb{Z}}_2$-symmetric potential are reconsidered, including the LHC data on existence of a 125 GeV Higgs-like boson. We analyze the model in which only one of the doublets develops a nonzero vacuum expectation value (VEV)—the inert doublet model (IDM) and the mixed model where both of the doublets have nonzero VEVs. Positivity constraints, conditions determining the type of the vacuum, perturbative unitarity condition, constraints following from electroweak precision tests together with the LEP bounds on masses of the scalars are included in the analysis. The analysis is performed without specific assumptions regarding the Yukawa sector. For the IDM constraints on quartic couplings and masses of the scalars as well as their implications for dark matter scenarios are presented. A new type of bound on the mass parameter of the potential coming from the condition for the existence of the inert vacuum is given. In the mixed model a strong bound on the value of $\tan \beta$, $0.18\lesssim \tan \beta \lesssim 5.59$, is found. It depends on the mass of the Higgs boson and is independent of the Yukawa interactions. Also standard model (SM)-like scenarios with either $h$ or $H$ playing the role of the SM-like Higgs boson are analyzed.

Recently, two measures of electroweak fine tuning (EWFT) have been introduced for (supersymmetry) SUSY models: ${\Delta }_{\mathrm{EW}}$ compares the $Z$ mass to each separate weak scale contribution to $m_Z$, while ${\Delta }_{\mathrm{HS}}$ compares the $Z$ mass to high scale input parameters and their consequent renormalization group evolution ($1/\Delta$ is the percent of fine tuning). While the paradigm mSUGRA/CMSSM model has been shown to be highly fine tuned under both parameters (${\Delta }_{\mathrm{EW}}\gtrsim {10}^2$ and ${\Delta }_{\mathrm{HS}}\gtrsim {10}^3$), the two-parameter nonuniversal Higgs model (NUHM2) in the context of radiatively driven natural SUSY (RNS) enjoys ${\Delta }_{\mathrm{EW}}$ as low as 10, while ${\Delta }_{\mathrm{HS}}$ remains $\gtrsim {10}^3$. We investigate fine tuning in the 19-free-parameter SUGRA model (SUGRA19). We find that with 19 free parameters, the lowest ${\Delta }_{\mathrm{EW}}$ points are comparable to what can be achieved in NUHM2 with just six free parameters. However, in SUGRA19, ${\Delta }_{\mathrm{HS}}$ can now also reach as low as 5–10. The conditions which lead to low ${\Delta }_{\mathrm{HS}}$ include $m_{H_u}\sim m_Z$ at the high scale, with nonuniversal gaugino masses $M_{1,2}\gg M_3$ also at $m_{\mathrm{GUT}}$. The low ${\Delta }_{\mathrm{HS}}$ models are severely constrained by the $b\to s\gamma$ branching fraction. In both cases of low ${\Delta }_{\mathrm{EW}}$ and ${\Delta }_{\mathrm{HS}}$, the superpotential $\mu$ parameter should be $\sim 100–300\mathrm{GeV}$. While SUSY models with low EWFT may or may not be discoverable at the LHC, the predicted light Higgsinos must show up at a linear $e^{+}{e}^{-}$ collider with $\sqrt{s}\gtrsim 2|\mu |$.

In a long distance Lagrangian approach to the low lying meson phenomenology, we present and discuss the most general spin zero multiquark interaction vertices of nonderivative type which include a set of effective interactions proportional to the current quark masses, breaking explicitly the chiral $SU(3{)}_L\times SU(3{)}_R$ and $U_A(1)$ symmetries. These vertices are of the same order in $N_c$, counting as the ’t Hooft flavor determinant interaction and the eight quark interactions which extend the original four quark interaction Lagrangian, leading in $N_c$, of Nambu and Jona-Lasinio. The $N_c$ assignments match the counting rules based on arguments set by the scale of spontaneous chiral symmetry breaking. With path-integral bosonization techniques which appropriately take into account the quark mass differences, we derive the mesonic Lagrangian up to three-point mesonic vertices. We demonstrate that explicit symmetry breaking effects in interactions are essential to obtain the correct empirical ordering and magnitude of the splitting of certain states such as $m_K<m_{\eta }$ for the pseudoscalars and $m_{{\kappa }_0}<m_{a_0}\sim m_{f_0}$ in the scalar sector, and to achieve total agreement with the empirical low lying meson mass spectra. With all parameters of the model fixed by the spectra, we analyze further a bulk of two-body decays at the tree level of the bosonic Lagrangian: the strong decays of the scalars $\sigma \to \pi \pi$, $f_0(980)\to \pi \pi$, $\kappa (800)\to \pi K$, and $a_0(980)\to \pi \eta$, as well as the two photon decays of $a_0(980)$, $f_0(980)$, and $\sigma$ mesons, and the anomalous decays of the pseudoscalars $\pi \to \gamma \gamma$, $\eta \to \gamma \gamma$, and ${\eta }^{\prime }\to \gamma \gamma$. Our results for the strong decays are within the current expectations and the pseudoscalar radiative decays are in very good agreement with data. The radiative decays of the scalars are smaller than the observed values for the $f_0(980)$ and the $\sigma$, but reasonable for the $a_0$. A detailed discussion accompanies all the results.

The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft $m_{\mathrm{jet}}^2/p_T^{\mathrm{jet}}$ scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from nonglobal logarithms depending on the ratio of the jet mass and jet-veto variables. For our exclusive jet cross section these nonglobal logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size $R$ are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in PYTHIA. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.

A simple theoretical framework for the spontaneous breaking of parity, and baryon and lepton numbers is proposed. In this context, the baryon and lepton numbers are independent local gauge symmetries, while parity is defined making use of the left-right symmetry. We show that in the minimal model the new leptoquark fields needed to define an anomaly-free theory also generate neutrino masses through the type III seesaw mechanism. The spectrum of neutrinos and some phenomenological aspects are discussed. This theory predicts the possible existence of two light sterile neutrinos.

A measurement of the rate for the “wrong-sign” decay $D^0\to K^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ relative to that for the “right-sign” decay $D^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-}$ is presented. Using $791{\mathrm{fb}}^{-1}$ of data collected with the Belle detector, we obtain a branching fraction ratio of $R_{\mathrm{ws}}=[0.324\pm 0.008(\mathrm{stat})\pm 0.007(\mathrm{sys})]\%$. Multiplying this ratio by the world average value for the branching fraction $\mathcal{B}(D^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-})$ gives a branching fraction $\mathcal{B}(D^0\to K^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-})=(2.61\pm {0.06}_{-0.08}^{+0.09})\times {10}^{-4}$.

The directional weak decay constants of neutral pions are determined at finite temperature $T$, chemical potential $\mu$ and in the presence of a constant magnetic field $B$. To do this, we first derive the energy dispersion relation of neutral pions from the corresponding effective action of a two-flavor, hot and magnetized Nambu–Jona-Lasinio model. Using this dispersion relation, including nontrivial directional refraction indices, we then generalize the partially conserved axial vector current relation of neutral pions and derive the Goldberger-Treiman as well as the Gell–Mann-Oakes-Renner relations consisting of the directional quark-pion coupling constant $g_{qq{\pi }^0}^{(\mu )}$ and the weak decay constant $f_{{\pi }^0}^{(\mu )}$ of neutral pions. The temperature dependence of $g_{qq{\pi }^0}^{(\mu )}$ and $f_{{\pi }^0}^{(\mu )}$ are then determined for fixed chemical potential and various constant background magnetic fields. The Goldberger-Treiman and Gell–Mann-Oakes-Renner relations are also verified at finite $T$, $\mu$ and $eB$. It is shown that, because of the explicit breaking of the Lorentz invariance by the magnetic field, the directional quark-pion coupling and decay constants of neutral pions in the longitudinal and transverse directions with respect to the direction of the external magnetic field are different, i.e., $g_{qq{\pi }^0}^{\parallel }\ne g_{qq{\pi }^0}^{\perp }$ and $f_{{\pi }^0}^{\parallel }\ne f_{{\pi }^0}^{\perp }$. As it turns out, for fixed $T$, $\mu$ and $B$, $g_{qq{\pi }^0}^{\parallel }>g_{qq{\pi }^0}^{\perp }$ and $f_{{\pi }^0}^{\parallel }<f_{{\pi }^0}^{\perp }$.

We present firstly the master equation of an electromagnetic perturbation with Weyl correction in the four-dimensional black hole spacetime, which depends not only on the Weyl correction parameter, but also on the parity of the electromagnetic field. It is quite different from that of the usual electromagnetic perturbation without Weyl correction in the four-dimensional spacetime. And then we have investigated numerically the dynamical evolution of the electromagnetic perturbation with Weyl correction in the background of a four-dimensional Schwarzschild black hole spacetime. Our results show that the Weyl correction parameter $\alpha$ and the parities imprint in the wave dynamics of the electromagnetic perturbation. For the odd parity electromagnetic perturbation, we find it grows with exponential rate if the value of $\alpha$ is below the negative critical value ${\alpha }_c$. However, for the electromagnetic perturbation with even parity, we find that there does not exist such a critical threshold value and the electromagnetic field always decays in the allowed range of $\alpha$.

We investigate the nature of the AdS/CFT duality between a subregion of the bulk and its boundary. In global AdS/CFT in the classical $G_N=0$ limit, the duality reduces to a boundary value problem that can be solved by restricting to one-point functions of local operators in the conformal field theory (CFT). We show that the solution of this boundary value problem depends continuously on the CFT data. In contrast, the anti–de Sitter (AdS)-Rindler subregion cannot be continuously reconstructed from local CFT data restricted to the associated boundary region. Motivated by related results in the mathematics literature, we posit that a continuous bulk reconstruction is only possible when every null geodesic in a given bulk subregion has an endpoint on the associated boundary subregion. This suggests that a subregion duality for AdS-Rindler, if it exists, must involve nonlocal CFT operators in an essential way.

Several model-independent parametrizations of deviations from general relativity have been developed to test Einstein’s theory. Although these different parametrizations were developed for different gravitational observables, they ultimately all test the same underlying physics. In this paper, we develop connections between the parametrized post-Newtonian, parametrized post-Keplerian, and the parametrized post-Einsteinian frameworks, developed to carry out tests of general relativity with Solar System, binary pulsar, and gravitational wave observations, respectively. These connections, although only valid under certain assumptions such as energy/momentum conservation, allow us to use knowledge gained from one framework to inform and guide tests using the others. Relating these parametrizations and combining the results from each approach strengthens our tests of general relativity.

We present new constraints on the rest-frame sound speed, $c_{\mathrm{eff}}^2$, and the viscosity parameter, $c_{\mathrm{vis}}^2$, of the cosmic neutrino background from the recent measurements of the cosmic microwave background anisotropies provided by the Planck satellite. While broadly consistent with the expectations of $c_{\mathrm{eff}}^2=c_{\mathrm{vis}}^2=1/3$ in the standard scenario, the Planck data set hints at a higher value of the viscosity parameter, with $c_{\mathrm{vis}}^2=0.60\pm 0.18$ at 68% C.L., and a lower value of the sound speed, with $c_{\mathrm{eff}}^2=0.304\pm 0.013$ at 68% C.L. We find a correlation between the neutrino parameters and the lensing amplitude of the temperature power spectrum $A_{\mathrm{L}}$. When the latter parameter is allowed to vary, we find a better consistency with the standard model with $c_{\mathrm{vis}}^2=0.51\pm 0.22$, $c_{\mathrm{eff}}^2=0.311\pm 0.019$, and $A_{\mathrm{L}}=1.08\pm 0.18$ at 68% C.L. This result indicates that the anomalous large value of $A_{\mathrm{L}}$ measured by Planck could be connected to nonstandard neutrino properties. Including additional data sets from baryon acoustic oscillation surveys and the Hubble Space Telescope constraint on the Hubble constant, we obtain $c_{\mathrm{vis}}^2=0.40\pm 0.19$, $c_{\mathrm{eff}}^2=0.319\pm 0.019$, and $A_{\mathrm{L}}=1.15\pm 0.17$ at 68% C.L.; including the lensing power spectrum, we obtain $c_{\mathrm{vis}}^2=0.50\pm 0.19$, $c_{\mathrm{eff}}^2=0.314\pm 0.015$, and $A_{\mathrm{L}}=1.025\pm 0.076$ at 68% C.L. Finally, we investigate further degeneracies between the clustering parameters and other cosmological parameters.

Extracting parameter constraints from cosmological observations requires accurate determination of the covariance matrix for use in the likelihood function. We show here that uncertainties in the elements of the covariance matrix propagate directly to increased uncertainties in cosmological parameters. When the covariance matrix is determined by simulations, the resulting variance of the each parameter increases by a factor of order $1+N_b/N_s$, where $N_b$ is the number of bands in the measurement and $N_s$ is the number of simulations.

Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy of charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved coincide, in the perfectly conducting limit, with the ones obtainable in ideal magnetohydrodynamics where the anomalous currents are neglected. It is argued that this is the rationale for the ability to extend to anomalous magnetohydrodynamics the hydromagnetic solutions characterized by finite gyrotropy. The generally covariant aspects of the problem are addressed with particular attention to conformally flat geometries which are potentially relevant for the description of the electroweak plasma prior to the phase transition.

We study a general form for the dissipative coefficient $\Gamma (T,\varphi )=C_{\varphi }{T}^m/{\varphi }^{m-1}$ in the context of warm intermediate and logamediate inflationary universe models. We analyze these models in the weak and strong dissipative regimes. In the slow-roll approximation, we describe in great detail the characteristics of these models. In both regimes, we use recent data from the WMAP nine-year data and Planck data to constrain the parameters appearing in our models.

We study the holographic and agegraphic dark energy models without interaction using the latest observational Hubble parameter data , the Union2.1 compilation of type Ia supernovae , and the energy conditions. Scenarios of dark energy are distinguished by the cutoff of cosmic age, conformal time, and event horizon. The best-fit value of matter density for the three scenarios almost steadily located at ${\Omega }_{m0}=0.26$ by the joint constraint. For the agegraphic models, they can be recovered to the standard cosmological model when the constant $c$ which presents the fraction of dark energy approaches to infinity. Absence of the upper limit of $c$ by the joint constraint demonstrates the recovery possibility. Using the fitted result, we also reconstruct the current equation of state of dark energy at different scenarios, respectively. Employing the model criteria ${\chi }_{\min }^2/\mathrm{dof}$, we find that conformal time model is the worst, but they cannot be distinguished clearly. Comparing with the observational constraints, we find that the strong energy condition is fulfilled at redshift $0.2\lesssim z\lesssim 0.3$ with $1\sigma$ confidence level. We also find that the null energy condition gives a meaningful constraint for the event horizon cutoff model, especially compared with observational Hubble parameter data only. We note that the energy condition maybe could play an important role in the interacting models because of different degeneracy between ${\Omega }_m$ and constant $c$.

We obtain analytical gravitational waveforms in the frequency domain for precessing, quasicircular compact binaries with small spins, applicable, for example, to binary neutron star inspirals. We begin by calculating an analytic solution to the precession equations, obtained by expanding in the dimensionless spin parameters and using multiple-scale analysis to separate time scales. We proceed by analytically computing the Fourier transform of time-domain waveform through the stationary phase approximation. We show that the latter is valid for systems with small spins. Finally, we show that these waveforms have a high overlap with numerical waveforms obtained through direct integration of the precession equations and discrete Fourier transformations. The resulting, analytic waveform family is ideal for detection and parameter estimation of gravitational waves emitted by inspiraling binary neutron stars with ground-based detectors.

We use WMAP-9 and other CMB data to constrain cosmological models where the primordial perturbations have both an adiabatic and a (possibly correlated) neutrino density (NDI), neutrino velocity (NVI), or cold dark matter density (CDI) isocurvature component. For NDI and CDI we use both a phenomenological approach, where primordial perturbations are parametrized in terms of amplitudes at two scales, and a slow-roll two-field inflation approach, where slow-roll parameters are used as primary parameters. For NVI we use only the phenomenological approach, since it is difficult to imagine a connection with inflation. We find that in the NDI and NVI cases larger isocurvature fractions are allowed than in the corresponding models with CDI. For uncorrelated perturbations, the upper limit to the primordial NDI (NVI) fraction is 24% (20%) at $k=0.002{\mathrm{Mpc}}^{-1}$ and 28% (16%) at $k=0.01{\mathrm{Mpc}}^{-1}$. For maximally correlated (anticorrelated) perturbations, the upper limit to the NDI fraction is 3.0% (0.9%). The nonadiabatic contribution to the CMB temperature variance can be as large as 10% ($-13\%$) for the NDI (NVI) modes. Bayesian model comparison favors the pure adiabatic initial mode over the mixed primordial adiabatic and NDI, NVI, or CDI perturbations. At best, the betting odds for a mixed model (uncorrelated NDI) are $1:3.4$ compared to the pure adiabatic model. For the phenomenological generally correlated mixed models the odds are about $1:100$, whereas the slow-roll approach leads to $1:13$ (NDI) and $1:51$ (CDI).