We evaluate the octupole in the large-$N_c$ limit in the McLerran-Venugopalan model and derive a general expression of the 2n-point correlator, which can be applied in analytical studies of the multiparticle production in the scatterings between hard probes and dense targets.

The renormalization that relates a coupling “a” associated with a distinct renormalization group beta function in a given theory is considered. Dimensional regularization and mass independent renormalization schemes are used in this discussion. It is shown how the renormalization $a^{*}=a+x_2{a}^2$ is related to a change in the mass scale $\mu$ that is induced by renormalization. It is argued that the infrared fixed point is to be a determined in a renormalization scheme in which the series expansion for a physical quantity $R$ terminates.

The lack of observation of supersymmetry thus far implies that the weak supersymmetry scale is larger than what was thought before the LHC era. This observation is strengthened by the Higgs boson mass measurement at $\sim 125\mathrm{GeV}$, which within supersymmetric models implies a large loop correction and a weak supersymmetry scale lying in the several TeV region. In addition if neutralino is the dark matter, its relic density puts further constraints on models often requiring coannihilation to reduce the neutralino relic density to be consistent with experimental observation. The coannihilation in turn implies that the mass gap between the lightest supersymmetric particle and the next to lightest supersymmetric particle will be small, leading to softer final states and making the observation of supersymmetry challenging. In this work we investigate stau coannihilation models within supergravity grand unified models and the potential of discovery of such models at the LHC in the post–Higgs boson discovery era. We utilize a variety of signal regions to optimize the discovery of supersymmetry in the stau coannihilation region. In the analysis presented we impose the relic density constraint as well as the constraint of the Higgs boson mass. The range of sparticle masses discoverable up to the optimal integrated luminosity of the HL-LHC is investigated. It is found that the mass difference between the stau and the neutralino does not exceed $\sim 20\mathrm{GeV}$ over the entire mass range of the models explored. Thus the discovery of a supersymmetric signal arising from the stau coannihilation region will also provide a measurement of the neutralino mass. The direct detection of neutralino dark matter is analyzed within the class of stau coannihilation models investigated. The analysis is extended to include multiparticle coannihilation where stau along with chargino and the second neutralino enter into the coannihilation process.

We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with $N_f=2$ flavors of twisted mass clover-improved fermions with a physical value of the pion mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed nonperturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are $g_S^u=5.20(42)(15)(12)$, $g_S^d=4.27(26)(15)(12)$, $g_S^s=0.33(7)(1)(4)$, and $g_S^c=0.062(13)(3)(5)$ and for the tensor charges $g_T^u=0.794(16)(2)(13)$, $g_T^d=-0.210(10)(2)(13)$, $g_T^s=0.00032(24)(0)$, and $g_T^c=0.00062(85)(0)$ in the $\overline{\mathrm{MS}}$ scheme at 2 GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from estimating the contamination due to the excited states, when our data are precise enough to probe the first excited state.

We propose a practical effective model by introducing temperature ($T$) dependence to the coupling strengths of four-quark and six-quark Kobayashi–Maskawa–’t Hooft interactions in the $2+1$ flavor Polyakov-loop extended Nambu–Jona-Lasinio model. The $T$ dependence is determined from lattice QCD (LQCD) data on the renormalized chiral condensate around the pseudocritical temperature $T_c^{\chi }$ of chiral crossover and the screening-mass difference between $\pi$ and $a_0$ mesons in $T>1.1T_c^{\chi }$ where only the $U(1{)}_{\mathrm{A}}$-symmetry breaking survives. The model well reproduces LQCD data on screening masses $M_{\xi }^{\mathrm{scr}}(T)$ for both pseudoscalar mesons ($\xi =\pi ,K,\eta ,{\eta }^{\prime }$) and scalar ones ($\xi =a_0,\kappa ,\sigma ,f_0$), particularly in $T\gtrsim T_c^{\chi }$. Using this effective model, we predict meson pole masses $M_{\xi }^{\mathrm{pole}}(T)$ for scalar and pseudoscalar mesons. For ${\eta }^{\prime }$ meson, the prediction is consistent with the experimental value at finite $T$ measured in heavy-ion collisions. We point out that the relation $M_{\xi }^{\mathrm{scr}}(T)-M_{\xi }^{\mathrm{pole}}(T)\approx M_{{\xi }^{\prime }}^{\mathrm{scr}}(T)-M_{{\xi }^{\prime }}^{\mathrm{pole}}(T)$ is pretty good when $\xi$ and ${\xi }^{\prime }$ are the scalar mesons, and show that the relation $M_{\xi }^{\mathrm{scr}}(T)/M_{{\xi }^{\prime }}^{\mathrm{scr}}(T)\approx M_{\xi }^{\mathrm{pole}}(T)/M_{{\xi }^{\prime }}^{\mathrm{pole}}(T)$ is well satisfied within 20% error when $\xi$ and ${\xi }^{\prime }$ are the pseudoscalar mesons and also when $\xi$ and ${\xi }^{\prime }$ are the scalar mesons.

In the Standard Model (SM) we calculate the decay rate of the neutron radiative ${\beta }^{-}$ decay to order $O({\alpha }^2/{\pi }^2\sim {10}^{-5})$, where $\alpha$ is the fine-structure constant, and radiative corrections to order $O(\alpha /\pi \sim {10}^{-3})$. The obtained results together with the recent analysis of the neutron radiative ${\beta }^{-}$ decay to next-to-leading order in the large proton-mass expansion, performed by Ivanov et al. [Phys. Rev. D 95, 033007 (2017)], describe recent experimental data by the RDK II Collaboration [Bales et al., Phys. Rev. Lett. 116, 242501 (2016)] within 1.5 standard deviations. We argue a substantial influence of strong low-energy interactions of hadrons coupled to photons on the properties of the amplitude of the neutron radiative ${\beta }^{-}$ decay under gauge transformations of real and virtual photons.

We study physical properties of constant curvature black holes in Einstein–anti-de Sitter (AdS) gravity. These objects, which are locally AdS throughout the space, are constructed from identifications of global AdS spacetime, in a similar fashion as the Banados-Teitelboim-Zanelli black hole in three dimensions. We find that, in dimensions equal to or greater than 4, constant curvature black holes have zero mass and angular momentum. Only in odd dimensions are we able to associate a nonvanishing conserved quantity to these solutions, which corresponds to the vacuum (Casimir) energy of the spacetime.

We introduce simple generic models of surface dynamics in loop quantum gravity (LQG). A quantum surface is defined as a set of elementary patches of area glued together. We provide it with an extra structure of locality (nearest neighbors), thought of as induced by the whole spin network state defining the 3d bulk geometry around the quantum surface. Here, we focus on classical surface dynamics, using a spinorial description of surface degrees of freedom. We introduce two classes of dynamics, to be thought as templates for future investigation of LQG dynamics with the dynamics of quantum black holes in mind. The first defines global dynamics of the closure defect of the surface, with two basic toy models, either a dissipative dynamics relaxing towards the closure constraint or a Hamiltonian dynamics precessing the closure defect. The second class of dynamics describes the isolated regime, when both area and closure defect are conserved throughout the evolution. The surface dynamics is implemented through $\mathrm{U}(N)$ transformations and generalizes to a Bose-Hubbard Hamiltonian with a local quadratic potential interaction. We briefly discuss the implications of modeling the quantum black hole dynamics by a surface Bose-Hubbard model.

We extend the classical results on the symmetry inheritance of the canonical electromagnetic fields, described by the Maxwell’s Lagrangian, to a much wider class of models, which include those of the Born-Infeld, power Maxwell and the Euler-Heisenberg type. Symmetry inheriting fields allow the introduction of electromagnetic scalar potentials and these are proven to be constant on the Killing horizons. Finally, using the relations obtained along the analysis, we generalize and simplify the recent proof for the symmetry inheritance of the 3-dimensional case, as well as give the first constraint for the higher dimensional electromagnetic fields.

We show that a partially massless graviton can propagate on a large set of spacetimes which are not Einstein spacetimes. Starting from a recently constructed theory for a massive graviton that propagates the correct number of degrees of freedom on an arbitrary spacetime, we first give the full explicit form of the scalar constraint responsible for the absence of a sixth degree of freedom. We then spell out generic conditions for the constraint to be identically satisfied, so that there is a scalar gauge symmetry which makes the graviton partially massless. These simplify if one assumes that spacetime is Ricci symmetric. Under this assumption, we find explicit non-Einstein spacetimes (some, but not all, with vanishing Bach tensors) allowing for the propagation of a partially massless graviton. These include in particular the Einstein static Universe.

We construct exact solutions representing a Friedmann-Lemaître-Robsertson-Walker (FLRW) universe in a generalized hybrid metric-Palatini theory. By writing the gravitational action in a scalar-tensor representation, the new solutions are obtained by either making an ansatz on the scale factor or on the effective potential. Among other relevant results, we show that it is possible to obtain exponentially expanding solutions for flat universes even when the cosmology is not purely vacuum. We then derive the classes of actions for the original theory which generate these solutions.

The ($2+1$)-dimensional non-Fermi liquid (NFL) has a dual description in the ($3+1$)-dimensional anti–de Sitter (AdS) spacetime. We begin with a dyonic Reissner-Nordstrom (RN) black brane background, and consider the bulk Dirac fermion field coupled with the background $U(1)$ gauge field, as well an intrinsic axial gauge field which is induced by chiral anomaly. The axial gauge field is effectively induced from the topological term in the bulk, which would lead to nontrivial effects on the boundary NFL. We study these effects through calculating the retarded Green’s functions of the dual NFL holographically, in both analytical and numerical approaches. We also obtain correlation functions in the low frequency limit at zero and finite temperatures, as well as the dispersion spectrum of the Dirac cones, Fermi arc of the surface states, which can be related with the experiment.

Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we present a third possibility, using only dark matter (DM) and ordinary matter. The mechanism relies on the coupling between dark matter and ordinary matter through an effective metric. Dark matter couples to an Einstein-frame metric, and experiences a matter-dominated, decelerating cosmology up to the present time. Ordinary matter couples to an effective metric that depends also on the DM density, in such a way that it experiences late-time acceleration. Linear density perturbations are stable and propagate with arbitrarily small sound speed, at least in the case of “pressure” coupling. Assuming a simple parametrization of the effective metric, we show that our model can successfully match a set of basic cosmological observables, including luminosity distance, baryon acoustic oscillation measurements, angular-diameter distance to last scattering, etc. For the growth history of density perturbations, we find an intriguing connection between the growth factor and the Hubble constant. To get a growth history similar to the $\mathrm{\Lambda }\mathrm{CDM}$ prediction, our model predicts a higher $H_0$, closer to the value preferred by direct estimates. On the flip side, we tend to overpredict the growth of structures whenever $H_0$ is comparable to the Planck preferred value. The model also tends to predict larger redshift-space distortions at low redshift than $\mathrm{\Lambda }\mathrm{CDM}$.

We use a variant of the $D4-D8$ construction that includes two chiral and one heavy meson, to describe heavy-light baryons and their exotics as heavy mesons bound to a flavor instanton in bulk. At strong coupling, the heavy meson is shown to always bind in the form of a flavor instanton zero mode in the fundamental representation. The ensuing instanton moduli for the heavy baryons exhibits both chiral and heavy quark symmetry. We detail how to quantize it, and derive model independent mass relations for heavy baryons with a single-heavy quark in leading order, in overall agreement with the reported baryonic spectra with one charm or bottom. We also discuss the low-lying masses and quantum assignments for the even and odd parity states, some of which are yet to be observed. We extend our analysis to double-heavy pentaquarks with hidden charm and bottom. In leading order, we find a pair of double-heavy iso-doublets with $I{J}^{\pi }=\frac{1}{2}{\frac{1}{2}}^{-},\frac{1}{2}{\frac{3}{2}}^{-}$ assignments for all heavy flavor combinations. We also predict five new Delta-like pentaquark states with $I{J}^{\pi }=\frac{3}{2}{\frac{1}{2}}^{-},\frac{3}{2}{\frac{3}{2}}^{-},\frac{3}{2}{\frac{5}{2}}^{-}$ assignments for both charm and bottom.

Mesonic and nucleon fluctuation effects are investigated in medium. We couple the nucleon field to the $2+1$ flavor meson model and investigate the finite temperature and density behavior of the system, in particular, the axial anomaly function. Somewhat contrary to earlier expectations, we find that it tends to strengthen at finite density. At lower temperatures, nucleon density fluctuations can cause a relative difference in the $U_A(1)$ axial anomaly of about 20%. This has important consequences on the mesonic spectra, especially on the $\eta -{\eta }^{\prime }$ system, as we observe no drop in the ${\eta }^{\prime }$ mass as a function of the baryochemical potential, irrespective of the temperature. Based on the details of chiral symmetry restoration, it is argued that there has to be a competition between underlying QCD effects of the anomaly and fluctuations of the low energy hadronic degrees of freedom, and the fate of the $U_A(1)$ coefficient should be decided by taking into account both effects simultaneously.

The interpretation of the baryon asymmetry of the Universe necessitates the $CP$ violation beyond the Standard Model (SM). We present a general cancellation mechanism in the theoretical predictions of the electron electric dipole moments (EDM), quark chromo-EDMs, and Weinberg operators. A relative large $CP$ violation in the Higgs sector is allowed by the current electron EDM constraint released by the ACME collaboration in 2013, and the recent ${}^{199}\mathrm{Hg}$ EDM experiment. The cancellation mechanism can be induced by the mass splitting of heavy Higgs bosons around $\sim \mathcal{O}(0.1–1)\mathrm{GeV}$, and the extent of the mass degeneracy determines the magnitude of the $CP$-violating phase. We explicate this point by investigating the $CP$-violating two-Higgs-doublet model and the minimal supersymmetric Standard Model. The cancellation mechanism is general when there are $CP$ violation and mixing in the Higgs sector of new physics models. The $CP$-violating phases in this scenario can be excluded or detected by the projected ${}^{225}\mathrm{Ra}$ EDM experiments with precision reaching $\sim {10}^{-28}e·\mathrm{cm}$, as well as the future colliders.

We study the sensitivity of the COHERENT experiment’s stopped pion source of neutrinos at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory to neutrino non-standard interactions (NSI). In particular, we find that simple event counting above threshold can improve constraints on NSI for electron- and muon-flavored NSI, with the strongest constraints arising for flavor-diagonal NSI coupling to $\mu$ neutrinos. However, if the detector resolution is sufficient to all for even a coarse spectral study of events, COHERENT will also be sensitive to the mass scale of NSI. We demonstrate that this can yield new limits on $Z^{\prime }$ completions of NSI if the gauge boson mass is $\lesssim 1\mathrm{GeV}$.

We present a dynamical cosmological solution that simultaneously accounts for the early inflationary stage of the Universe and solves the supersymmetric little hierarchy problem via the relaxion mechanism. First, we consider an inflationary potential arising from the $D$ term of a new $U(1)$ gauge symmetry with a Fayet-Iliopolous term that is independent of the relaxion. A technically natural, small $U(1)$ gauge coupling, $g\lesssim {10}^{-8}$, allows for a low Hubble scale of inflation, $H_I\lesssim 10^5\mathrm{GeV}$, which is shown to be consistent with Planck data. This feature is then used to realize a supersymmetric two-field relaxion mechanism, where the second field is identified as the inflaton provided that $H_I\lesssim 10\mathrm{GeV}$. The inflaton controls the relaxion barrier height allowing the relaxion to evolve in the early Universe and scan the supersymmetric soft masses. After electroweak symmetry is broken, the relaxion settles at a local supersymmetry-breaking minimum with a range of $F$-term values that can naturally explain supersymmetric soft mass scales up to $10^6\mathrm{GeV}$.

Previous studies of a three family Yukawa unified supersymmetric (SUSY) grand unified theory with SO(10) or Pati-Salam (PS) gauge symmetry proposed by Raby and students show that this model is able to fit low energy and inflation observables. However, the fit to low energy observables is not great especially for $\sin 2\beta$, and up and down quark masses. In this paper, we show that by choosing PS as the gauge group and modifying the Yukawa sector, the low energy fit improves significantly while other qualities of the model are maintained. In particular, the lightest SUSY particle is the neutralino with mass of order 300–500 GeV, the lightest stop and sbottom have mass of order 3–5 TeV, and the $CP$-odd Higgs mass is of order 5–6 TeV, so we are in the decoupling limit for the light Higgs boson. In addition, we reinterpret gluino simplified model analyses by the ATLAS and CMS collaborations and find that the most stringent gluino mass bound for our model is $M_{\tilde{g}}\sim 1.9\mathrm{TeV}$. The current best fit point, consistent with this bound, with gluino mass $M_{\tilde{g}}=1.9\mathrm{TeV}$ has ${\chi }^2/\mathrm{dof}\approx 1.12$, compared to the best fit point of the previous model with ${\chi }^2/\mathrm{dof}=1.90$. We find that predictions for the electric dipole moment of the electron, the branching ratio $\mathrm{BR}(\mu \to e\gamma )$ and the CP violating angle in the lepton sector, $\sin \delta$, are affected significantly as compared to previous results. In summary, we are unable to rule out this model or place an upper bound on gluino mass accessible by this run of the LHC because the ${\chi }^2/\mathrm{dof}$ of this model is well below $2\sigma$ even for a gluino mass as high as 2.7 TeV. On the bright side, this means that this model is still viable and we might find low energy SUSY particles in the near future.

Lattice QCD calculations with background magnetic fields are used to determine the magnetic moments of the octet baryons. Computations are performed at the physical value of the strange quark mass, and two values of the light quark mass, one corresponding to the $SU(3{)}_F$-symmetric point, where the pion mass is $m_{\pi }\sim 800\mathrm{MeV}$, and the other corresponding to a pion mass of $m_{\pi }\sim 450\mathrm{MeV}$. The moments are found to exhibit only mild pion-mass dependence when expressed in terms of appropriately chosen magneton units—the natural baryon magneton. A curious pattern is revealed among the anomalous baryon magnetic moments which is linked to the constituent quark model, however, careful scrutiny exposes additional features. Relations expected to hold in the large-$N_c$ limit of QCD are studied; and, in one case, a clear preference for the quark model over the large-$N_c$ prediction is found. The magnetically coupled $\mathrm{\Lambda }–{\mathrm{\Sigma }}^0$ system is treated in detail at the $SU(3{)}_F$ point, with the lattice QCD results comparing favorably with predictions based on $SU(3{)}_F$ symmetry. This analysis enables the first extraction of the isovector transition magnetic polarizability. The possibility that large magnetic fields stabilize strange matter is explored, but such a scenario is found to be unlikely.