With assumptions that the violation of the distance-duality relation entirely arises from nonconservation of the photon number and that the absorption is frequency independent in the observed frequency range, we perform cosmological-model-independent tests for the cosmic opacity. The observational data include the largest Union2.1 type Ia supernova sample, which is taken for observed $D_{\mathrm{L}}$, and galaxy cluster samples compiled by De Filippis et al. and Bonamente et al., which are responsible for providing observed $D_{\mathrm{A}}$. Two parametrizations, $\tau (z)=2ϵz$ and $\tau (z)=(1+z{)}^{2ϵ}-1$, are adopted for the optical depth associated with the cosmic absorption. We find that an almost transparent universe is favored by the Filippis et al. sample, but it is only marginally accommodated by the Bonomente et al. samples at 95.4% confidence level (C.L.) (even at 99.7% C.L. when the $r<100\mathrm{kpc}$-cut spherical $\beta$ model is considered). Taking the possible cosmic absorption (in the 68.3% C.L. range) constrained from the model-independent tests into consideration, we correct the distance moduli of SNe Ia and then use them to study their cosmological implications. The constraints on the $\Lambda \mathrm{CDM}$ show that a decelerating expanding universe with ${\Omega }_{\Lambda }=0$ is only allowed at 99.7% C.L. by observations when the Bonamente et al. sample is considered. Therefore, our analysis suggests that an accelerated cosmic expansion is still needed to account for the dimming of SNe, and the standard cosmological scenario remains being supported by current observations.

Inspiraling binaries of compact objects are primary targets for current and future gravitational-wave observatories. Waveforms computed in general relativity are used to search for these sources, and will probably be used to extract source parameters from detected signals. However, if a different theory of gravity happens to be correct in the strong-field regime, source-parameter estimation may be affected by a fundamental bias: that is, by systematic errors due to the use of waveforms derived in the incorrect theory. If the deviations from general relativity are not large enough to be detectable on their own and yet these systematic errors remain significant (i.e., larger than the statistical uncertainties in parameter estimation), fundamental bias cannot be corrected in a single observation, and becomes stealth bias. In this article we develop a scheme to determine in which cases stealth bias could be present in gravitational-wave astronomy. For a given observation, the answer depends on the detection signal-to-noise ratio and on the strength of the modified-gravity correction. As an example, we study three representative stellar-mass binary systems that will be detectable with second-generation ground-based observatories. We find that significant systematic bias can occur whether or not modified gravity can be positively detected, for correction strengths that are not currently excluded by any other experiment. Thus, stealth bias may be a generic feature of gravitational-wave detections, and it should be considered and characterized, using expanded models such as the parametrized post-Einstein framework, when interpreting the results of parameter-estimation analyses.

A new idea for neutrino mass was proposed recently, where its smallness is not due to the seesaw mechanism, i.e., not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting of singlet Majorana fermions $N_i$ with masses of order 10 keV, and neutrino masses are scaled down from them by factors of about ${10}^{-5}$. We discuss how this model may be implemented with the non-Abelian discrete symmetry $A_4$ for neutrino mixing and consider the phenomenology of $N_i$ as well as the extra scalar doublet $({\eta }^{+},{\eta }^0)$.

We revisit the status of lepton flavor violating (LFV) $\mu eqq$ contact interactions from the view point of ${\mu }^{-}-e^{-}$ conversion in nuclei. We consider their contribution to this LFV process via the two mechanisms on the hadronic level: direct nucleon and meson exchange ones. In the former case the quarks are embedded directly into the nucleons while in the latter in mesons which then interact with nucleons in a nucleus. We revise and in some cases reevaluate the hadronic parameters relevant for both mechanisms and calculate the contribution of the above mentioned contact interactions in coherent ${\mu }^{-}-e^{-}$ conversion in various nuclei. Then we update our previous upper bounds and derive new ones for the scales of the $\mu eqq$ contact interactions from the experimental limits on the capture rates of ${\mu }^{-}-e^{-}$ conversion. We compare these limits with the ones derived in the literature from other LFV processes and comment on the prospects of LHC searches related to the contact $\mu eqq$ interactions.

The determination of renormalization factors is of crucial importance in lattice QCD. They relate the observables obtained on the lattice to their measured counterparts in the continuum in a suitable renormalization scheme. Therefore, they have to be computed as precisely as possible. A widely used approach is the nonperturbative Rome-Southampton method. It requires, however, a careful treatment of lattice artifacts. In this paper we investigate a method to suppress these artifacts by subtracting one-loop contributions to renormalization factors calculated in lattice perturbation theory. We compare results obtained from a complete one-loop subtraction with those calculated for a subtraction of contributions proportional to the square of the lattice spacing.

We revisit a two right-handed neutrino model with two texture zeros, namely an indirect model based on $A_4$ with the recently proposed new type of constrained sequential dominance (CSD2), involving vacuum alignments along the $(0,1,-1{)}^T$ and $(1,0,2{)}^T$ directions in flavor space, which are proportional to the neutrino Dirac mass matrix columns. In this paper we construct a renormalizable and unified indirect $A_4\times SU(5)$ model along these lines and show that, with spontaneous $CP$ violation and a suitable vacuum alignment of the phases, the charged lepton corrections lead to a reactor angle in good agreement with results from Daya Bay and RENO. The model predicts a right-angled unitarity triangle in the quark sector and a Dirac $CP$ violating oscillation phase in the lepton sector of $\delta \approx 130°$, while providing a good fit to all quark and lepton masses and mixing angles.

We discuss building models for nucleon generalized parton distributions $H$ and $E$ that are based on the formalism of double distributions (DDs). We found that the usual “$\mathrm{DD}+\mathrm{D}$-term” construction should be amended by an extra term, $\xi E_{+}^1(x,\xi )$ built from the $\alpha /\beta$ moment of the DD $e(\beta ,\alpha )$ that generates generalized parton distribution $E(x,\xi )$. Unlike the $D$ term, this function has support in the whole $-1\le x\le 1$ region, and in general does not vanish at the border points $|x|=\xi$.

We calculate the electromagnetic form factors of the scalar $K_0^{*}(1430)$, $f_0(1500)$ and $a_0(1450)$ mesons by considering them as regular quark-antiquark states and using their distribution amplitudes within the light-cone QCD sum rules approach.

The electromagnetic form factors of the $\Delta$ and $\Omega$ baryons are calculated in the framework of Poincaré-covariant bound-state equations. The quark-quark interaction is truncated to a single dressed-gluon exchange where for the dressings we use two different models and compare the results. The calculation predicts an oblate shape for the electric charge distribution and a prolate shape for the magnetic dipole distribution. We also identify the necessity of including pion-cloud corrections at low photon-momentum transfer.

The recent observation of a Higgs boson at the LHC and experimental confirmation of the nonvanishing neutrino-mixing parameter $\sin {\theta }_{13}$ offer important means to test physics beyond the standard model. We explore this within the context of the scotogenic model, in which neutrinos acquire mass radiatively via one-loop interactions with dark matter. Starting with a two-parameter neutrino-mixing matrix which is consistent with the latest neutrino-oscillation data at the one-sigma level, we derive different sets of solutions for the Yukawa couplings of the nonstandard particles in the model and use the results to consider the Higgs decays into final states involving the new particles. Assuming that the lightest one of them serves as fermionic cold dark matter, we show that such decays are allowed by various experimental and theoretical constraints to have substantial rates that are already restricted by the current LHC data. We also look at their correlations with the Higgs decays into $\gamma \gamma$ and $\gamma Z$. Upcoming LHC measurements of the Higgs boson can therefore either detect scotogenic signals or place further constraints on the model.

We present physical results for a variety of light hadronic quantities obtained via a combined analysis of three $2+1$ flavour domain wall fermion ensemble sets. For two of our ensemble sets we used the Iwasaki gauge action with $\beta =2.13$ ($a^{-1}=1.75(4)\mathrm{GeV}$) and $\beta =2.25$ ($a^{-1}=2.31(4)\mathrm{GeV}$) and lattice sizes of ${24}^3\times 64$ and ${32}^3\times 64$ respectively, with unitary pion masses in the range 293(5)–417(10) MeV. The extent $L_s$ for the 5th dimension of the domain wall fermion formulation is $L_s=16$ in these ensembles. In this analysis we include a third ensemble set that makes use of the novel $\mathrm{Iwasaki}+\mathrm{DSDR}$ (dislocation suppressing determinant ratio) gauge action at $\beta =1.75$ ($a^{-1}=1.37(1)\mathrm{GeV}$) with a lattice size of ${32}^3\times 64$ and $L_s=32$ to reach down to partially-quenched pion masses as low as 143(1) MeV and a unitary pion mass of 171(1) MeV, while retaining good chiral symmetry and topological tunneling. We demonstrate a significant improvement in our control over the chiral extrapolation, resulting in much improved continuum predictions for the above quantities. The main results of this analysis include the pion and kaon decay constants, $f_{\pi }=127(3{)}_{\mathrm{stat}}(3{)}_{\mathrm{sys}}\mathrm{MeV}$ and $f_K=152(3{)}_{\mathrm{stat}}(2{)}_{\mathrm{sys}}\mathrm{MeV}$ respectively ($f_K/f_{\pi }=1.199(12{)}_{\mathrm{stat}}(14{)}_{\mathrm{sys}}$); the average up/down quark mass and the strange-quark mass in the $\overline{\mathrm{MS}}$-scheme at 3 GeV, $m_{\mathrm{ud}}(\overline{\mathrm{MS}},3\mathrm{GeV})=3.05(8{)}_{\mathrm{stat}}(6{)}_{\mathrm{sys}}\mathrm{MeV}$ and $m_s(\overline{\mathrm{MS}},3\mathrm{GeV})=83.5(1.7{)}_{\mathrm{stat}}(1.1{)}_{\mathrm{sys}}$; the neutral kaon mixing parameter in the $\overline{\mathrm{MS}}$-scheme at 3 GeV, $B_K(\overline{\mathrm{MS}},3\mathrm{GeV})=0.535(8{)}_{\mathrm{stat}}(13{)}_{\mathrm{sys}}$, and in the RGI scheme, ${\widehat{B}}_K=0.758(11{)}_{\mathrm{stat}}(19{)}_{\mathrm{sys}}$; and the Sommer scales $r_1=0.323(8{)}_{\mathrm{stat}}(4{)}_{\mathrm{sys}}\mathrm{fm}$ and $r_0=0.480(10{)}_{\mathrm{stat}}(4{)}_{\mathrm{sys}}$ ($r_1/r_0=0.673(11{)}_{\mathrm{stat}}(3{)}_{\mathrm{sys}}$). We also obtain values for the SU(2) chiral perturbation theory effective couplings, $\overline{l_3}=2.91(23{)}_{\mathrm{stat}}(7{)}_{\mathrm{sys}}$ and $\overline{l_4}=3.99(16{)}_{\mathrm{stat}}(9{)}_{\mathrm{sys}}$.

We propose a recursive algorithm for the calculation of multibaryon correlation functions that combines the advantages of a recursive approach with those of the recently proposed unified contraction algorithm. The independent components of the correlators are built recursively by adding the baryons one after the other in a given order. The list of nonzero independent components is also constructed in a recursive manner, significantly reducing the resources required for this step. We computed the number of operations required to calculate the correlators up to ${}^8\mathrm{Be}$, and observed a significant speedup compared to other techniques. For the calculation of ${}^4\mathrm{He}$ and ${}^8\mathrm{Be}$ correlation functions in the fully relativistic case $\mathcal{O}({10}^8)$ operations are required, whereas for nonrelativistic operators this number can be reduced to, e.g., $\mathcal{O}({10}^4)$ in the case of ${}^4\mathrm{He}$.

In this article, we perform an extensive study of flavor observables in a two-Higgs-doublet model with generic Yukawa structure (of type III). This model is interesting not only because it is the decoupling limit of the minimal supersymmetric standard model but also because of its rich flavor phenomenology which also allows for sizable effects not only in flavor-changing neutral-current (FCNC) processes but also in tauonic $B$ decays. We examine the possible effects in flavor physics and constrain the model both from tree-level processes and from loop observables. The free parameters of the model are the heavy Higgs mass, $\tan \beta$ (the ratio of vacuum expectation values) and the “nonholomorphic” Yukawa couplings ${ϵ}_{ij}^f(f=u,d,\ell )$. In our analysis we constrain the elements ${ϵ}_{ij}^f$ in various ways: In a first step we give order of magnitude constraints on ${ϵ}_{ij}^f$ from ’t Hooft’s naturalness criterion, finding that all ${ϵ}_{ij}^f$ must be rather small unless the third generation is involved. In a second step, we constrain the Yukawa structure of the type-III two-Higgs-doublet model from tree-level FCNC processes ($B_{s,d}\to {\mu }^{+}{\mu }^{-}$, $K_L\to {\mu }^{+}{\mu }^{-}$, ${\overline{D}}^0\to {\mu }^{+}{\mu }^{-}$, $\Delta F=2$ processes, ${\tau }^{-}\to {\mu }^{-}{\mu }^{+}{\mu }^{-}$, ${\tau }^{-}\to e^{-}{\mu }^{+}{\mu }^{-}$ and ${\mu }^{-}\to e^{-}{e}^{+}{e}^{-}$) and observe that all flavor off-diagonal elements of these couplings, except ${ϵ}_{32,31}^u$ and ${ϵ}_{23,13}^u$, must be very small in order to satisfy the current experimental bounds. In a third step, we consider Higgs mediated loop contributions to FCNC processes [$b\to s(d)\gamma$, $B_{s,d}$ mixing, $K-\overline{K}$ mixing and $\mu \to e\gamma$] finding that also ${ϵ}_{13}^u$ and ${ϵ}_{23}^u$ must be very small, while the bounds on ${ϵ}_{31}^u$ and ${ϵ}_{32}^u$ are especially weak. Furthermore, considering the constraints from electric dipole moments we obtain constrains on some parameters ${ϵ}_{ij}^{u,\ell }$. Taking into account the constraints from FCNC processes we study the size of possible effects in the tauonic $B$ decays ($B\to \tau \nu$, $B\to D\tau \nu$ and $B\to D^{*}\tau \nu$) as well as in $D_{(s)}\to \tau \nu$, $D_{(s)}\to \mu \nu$, $K(\pi )\to e\nu$, $K(\pi )\to \mu \nu$ and $\tau \to K(\pi )\nu$ which are all sensitive to tree-level charged Higgs exchange. Interestingly, the unconstrained ${ϵ}_{32,31}^u$ are just the elements which directly enter the branching ratios for $B\to \tau \nu$, $B\to D\tau \nu$ and $B\to D^{*}\tau \nu$. We show that they can explain the deviations from the SM predictions in these processes without fine-tuning. Furthermore, $B\to \tau \nu$, $B\to D\tau \nu$ and $B\to D^{*}\tau \nu$ can even be explained simultaneously. Finally, we give upper limits on the branching ratios of the lepton flavor-violating neutral $B$ meson decays ($B_{s,d}\to \mu e$, $B_{s,d}\to \tau e$ and $B_{s,d}\to \tau \mu$) and correlate the radiative lepton decays ($\tau \to \mu \gamma$, $\tau \to e\gamma$ and $\mu \to e\gamma$) to the corresponding neutral current lepton decays (${\tau }^{-}\to {\mu }^{-}{\mu }^{+}{\mu }^{-}$, ${\tau }^{-}\to e^{-}{\mu }^{+}{\mu }^{-}$ and ${\mu }^{-}\to e^{-}{e}^{+}{e}^{-}$). A detailed Appendix contains all relevant information for the considered processes for general scalar-fermion-fermion couplings.

We study inclusive dijet azimuthal decorrelations in proton-proton collisions at the CERN LHC invoking the hypothesis of parton Reggeization in $t$-channel exchanges at high energies. In the parton Reggeization approach, the main contribution to the azimuthal angle difference between the two most energetic jets is due to the Reggeon-Reggeon-particle-particle scattering, when the fusion of two Reggeized gluons into a pair of Yang-Mills gluons dominates. Using a high-energy factorization scheme with the Kimber-Martin-Ryskin unintegrated parton distribution functions and the Fadin-Lipatov effective vertices we obtain good agreement of our calculations with recent measurements by the ATLAS and CMS Collaborations at the CERN LHC.

We study the relativistic quark-antiquark system embedded in a magnetic field (MF). The Hamiltonian containing confinement, one gluon exchange, and spin-spin interaction is derived. We analytically follow the evolution of the lowest meson states as a function of MF strength. Calculating the one gluon exchange interaction energy $⟨V_{\mathrm{OGE}}⟩$ and spin-spin contribution $⟨a_{SS}⟩$ we have observed that these corrections remain finite at large MF, preventing the vanishing of the total $\rho$ meson mass at some $B_{\mathrm{crit}}$, as previously thought. We display the $\rho$ masses as functions of the MF in comparison with recent lattice data.

The form factors of the weak $B_s$ transitions to ground-state and orbitally excited strange mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. These form factors are expressed through the overlap integrals of meson wave functions found in their mass spectrum evaluations. The momentum dependence of the form factors is determined in the whole accessible kinematical range without any additional assumptions and extrapolations. Relativistic effects, including the wave function transformation from rest to a moving reference frame as well as the contributions of the intermediate negative-energy states, are consistently taken into account. The calculated form factors are used for the evaluation of the charmless semileptonic decay rates and two-body nonleptonic $B_s$ decays in the factorization approximation. The obtained results are confronted with previous predictions and available experimental data.

The bulk and shear viscosities of a pion gas are obtained by solving the relativistic transport equation in the Chapman-Enskog approximation. In-medium effects are introduced in the $\pi \pi$ cross section through one-loop self-energies in the propagator of the exchanged $\rho$ and $\sigma$ mesons. The effect of early chemical freeze-out in heavy ion collisions is implemented through a temperature-dependent pion chemical potential. These are found to affect the temperature dependence of the bulk and shear viscosities significantly.

Motivated by recent measurements of a relatively large ${\theta }_{13}$ in the Daya Bay and RENO reactor neutrino experiments, we carry out a systematic analysis of the hybrid textures of Majorana neutrino mass matrix $M_{\nu }$, which contain one texture zero and two equal nonzero matrix elements. We show that three neutrino masses $(m_1,m_2,m_3)$ and three leptonic $CP$-violating phases $(\delta ,\rho ,\sigma )$ can fully be determined from two neutrino mass-squared differences $(\delta m^2,\Delta m^2)$ and three flavor mixing angles $({\theta }_{12},{\theta }_{23},{\theta }_{13})$. Out of sixty logically possible patterns of $M_{\nu }$, thirty-nine are found to be compatible with current experimental data at the $3\sigma$ level. We demonstrate that the texture zero of $M_{\nu }$ is stable against one-loop quantum corrections, while the equality between two independent elements not. Phenomenological implications of $M_{\nu }$ for the neutrinoless double-beta decay and leptonic $CP$ violation are discussed, and a realization of the texture zero and equality by means of discrete flavor symmetries is illustrated.

Based on a sample of 225.3 million $J/\psi$ events accumulated with the BESIII detector at the BEPCII, the decays of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{l}^{+}{l}^{-}$ are studied via $J/\psi \to \gamma {\eta }^{\prime }$. A clear ${\eta }^{\prime }$ signal is observed in the ${\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ mass spectrum, and the branching fraction is measured to be $\mathcal{B}({\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-})=(2.11\pm 0.12(\mathrm{stat})\pm 0.14(\mathrm{syst}))\times {10}^{-3}$, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No ${\eta }^{\prime }$ signal is found in the ${\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ mass spectrum, and the upper limit is determined to be $\mathcal{B}({\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-})<2.9\times {10}^{-5}$ at the 90% confidence level.

We measure the ratio of cross sections, $\sigma (p\overline{p}\to Z+b\mathrm{\text{jet}})/\sigma (p\overline{p}\to Z+\mathrm{\text{jet}})$, for associated production of a $Z$ boson with at least one jet. The ratio is also measured as a function of the $Z$ boson transverse momentum, jet transverse momentum, jet pseudorapidity, and the azimuthal angle between the $Z$ boson with respect to the highest $p_T$ $b$ tagged jet. These measurements use data collected by the D0 experiment in Run II of Fermilab’s Tevatron $p\overline{p}$ Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of $9.7{\mathrm{fb}}^{-1}$. The results are compared to predictions from next-to-leading order calculations and various Monte Carlo event generators.