Modern Physics Letters A

An approach is discussed on the determination of the leading order hadronic contribution to the muon anomaly, $a_{\mu }^{\mathrm{\text{HAD}}}$, based entirely on theory. This method makes no use of $e^{+}{e}^{-}$ annihilation data, a likely source of the current discrepancy between theory and experiment beyond the 3$\sigma$ level. What this method requires is essentially knowledge of the first derivative of the vector current correlator at zero-momentum. In the heavy-quark sector, this is obtained from the well-known heavy-quark expansion in perturbative quantum chromodynamics (QCD), leading to values of $a_{\mu }^{\mathrm{\text{HAD}}}$ in the charm- and bottom-quark region which were fully confirmed by later lattice QCD (LQCD) results. In the light-quark sector, using recent preliminary LQCD results for the first derivative of the vector current correlator at zero-momentum leads to the value $a_{\mu }^{\mathrm{\text{HAD}}}=(729\text{–}871)\times 10^{-10}$, which is significantly larger than values obtained from using $e^{+}{e}^{-}$ data. A separate approach based on the operator product expansion (OPE), and designed to quench the contribution of these data, reduces the discrepancy by at least 40%. In addition, it exposes a tension between the OPE and $e^{+}{e}^{-}$ data, thus suggesting the blame for the discrepancy on the latter.

We compute the QCD coupling constant, ${\alpha }_s$, from the Adler function with vector hadronic vacuum polarization (HVP) function. On the lattice, Adler function can be measured by the differential of HVP at two different momentum scales. HVP is measured from the conserved-local vector current correlator using n_f = 2 + 1 flavor Domain Wall lattice data with three different lattice cutoffs, up to a${}^{-1}\approx$ 3.14 GeV. To avoid the lattice artifact due to O(4) symmetry breaking, we set the cylinder cut on the lattice momentum with reflection projection onto vector current correlator, and it then provides smooth function of momentum scale for extracted HVP. We present a global fit of the lattice data at a justified momentum scale with three lattice cutoffs using continuum perturbation theory at ${𝒪}({\alpha }_s^4)$ to obtain the coupling in the continuum limit at arbitrary scale. We take the running to Z boson mass through the appropriate thresholds, and obtain ${\alpha }_s^{(5)}$(M_Z) = 0.1191(24)(37) where the first is statistical error and the second is systematic one.

We investigate the sound absorption in quark matter due to the interaction of the sound wave with the precritical fluctuations of the diquark-pair field above $T_{\mathrm{\text{c}}}$. The soft collective mode of the pair field is derived using the time-dependent Ginzburg–Landau functional with random Langevin forces. The strong absorption near the phase transition line may be viewed as a manifestation of Mandelshtam–Leontovich slow relaxation time theory.

We point out that when doubly-charged bileptons are pair produced at the LHC, kinematics dictate that they are both almost at rest in the lab frame and therefore their decays lead to final state muons in a characteristic X-shape with only very tiny track curvature because of the high muon energies. Such X-events have essentially no Standard Model background and provide a smoking gun for the 331 model.

Electroweak observables are highly sensitive to the loop corrections. Therefore, a proper gauge-fixing mechanism is always needed to define the propagators which are involved in Feynman loop amplitude. With this spirit, we compute gauge-fixing mechanism in five-dimensional (5D) universal extra-dimensional (UED) model with boundary localized terms (BLTs). These BLTs are not 5D operators in four-dimensional (4D) effective theory but some sort of boundary conditions on the respective fields at the fixed points of $S^1/Z_2$ orbifold. Furthermore, these BLTs nontrivially modify the Kaluza–Klein (KK) spectra and some of the interactions among the KK-excitations compared to the minimal UED (mUED), in which, these BLTs are absent. In this note, we calculate the gauge-fixing mechanism in the electroweak sector of such nontrivial UED scenario. Moreover, we discuss the composition and masses of Goldstone and any physical scalar that emerge after the symmetry breaking in this set up with different choices of gauge.

The doubly-charged Higgs bosons $(H_5^{\pm \pm })$ are the typical particles predicted in the Georgi–Machacek (GM) model and their decay modes depend on the magnitude of the triplet vacuum expectation value (VEV) $v_{\mathrm{\Delta }}$. In this paper, we focus on the study of their pair production process at the International Linear Collider (ILC): $e^{+}{e}^{-}\to H_5^{++}{H}_5^{--}\to W^{+}{W}^{+}{W}^{-}{W}^{-}\to {\ell }^{-}{\ell }^{-}jjjjE{/}_T^{\mathrm{\text{miss}}}$, with the subsequent decay of two like-sign $W$ bosons through a pair of like-sign dileptons and the remaining two in their hadronic decays. The 5$\sigma$ confidence level discovery reach at the ILC is also studied with two collision energies of 1.0 TeV and 1.5 TeV.

We discuss the relation between Noether (point) symmetries and discrete symmetries for a class of minisuperspace cosmological models. We show that when a Noether symmetry exists for the gravitational Lagrangian, then there exists a coordinate system in which a reversal symmetry exists. Moreover, as far as concerns, the scale-factor duality symmetry of the dilaton field, we show that it is related to the existence of a Noether symmetry for the field equations, and the reversal symmetry in the normal coordinates of the symmetry vector becomes scale-factor duality symmetry in the original coordinates. In particular, the same point symmetry as also the same reversal symmetry exists for the Brans–Dicke scalar field with linear potential while now the discrete symmetry in the original coordinates of the system depends on the Brans–Dicke parameter and it is a scale-factor duality when ${\omega }_{\mathrm{\text{BD}}}=1$. Furthermore, in the context of the O’Hanlon theory for f(R)-gravity, it is possible to show how a duality transformation in the minisuperspace can be used to relate different gravitational models.

We examine Podolsky’s electrodynamics, which is non-invariant under the usual duality transformation. We deduce a generalization of Hodge’s star duality, which leads to a dual gauge field and restores to a certain extent the dual symmetry. The model becomes fully dual symmetric asymptotically, when it reduces to the Maxwell theory. We argue that this strict dual symmetry directly implies the existence of the basic invariants of the electromagnetic fields.