Long time limit of equilibrium glassy dynamics and replica calculation

It is shown that the limit t−t^′→∞$t-t^{\prime }\to \infty$ of the equilibrium dynamic self-energy can be computed from the n→1$n\to 1$ limit of the static self-energy of an n  -times replicated system with one step replica symmetry breaking structure. It is also shown that the Dyson equation of the replicated system leads in the n→1$n\to 1$ limit to the bifurcation equation for the glass ergodicity breaking parameter computed from dynamics. The equivalence of the replica formalism to the long time limit of the equilibrium relaxation dynamics is proved to all orders in perturbation for a scalar theory.     

Leading-twist shadowing,black disk regime and forward hadron production

We review theory of the leading-twist nuclear shadowing, and describe phenomenon of post-selection suppression of leading parton spectrum (effective fractional energy losses) in the proximity of the black disk regime. We argue that 2→2$2\to 2$ mechanism dominates in the inclusive leading pion production in d-Au collisions and explain that the post-selection naturally explains both the magnitude of the suppression of the forward pion production in d-Au   collisions and the pattern of the forward–central correlations. At the same time this pattern of correlations rules out 2→1$2\to 1$ mechanism as the main source of the inclusive leading pion yield. It is demonstrated that the mechanism of the double-parton interactions gives an important contribution to the production of two leading pions in pp   scattering opening a new way to study correlations of leading quarks in the nucleon. The same mechanism is enhanced in dAu→π⁰π⁰+X$dAu\to {\pi }^0{\pi }^0+X$ collisions and explains the dominance of Δφ independent component and suppression of the away side peak.     

If Gauss–Bonnet interaction plays the role of dark energy

A cosmological model has been constructed with Gauss–Bonnet-scalar interaction, where the Universe starts with exponential expansion but encounters infinite deceleration, q→∞$q\to \infty$ and infinite equation of state parameter, w→∞$w\to \infty$. During evolution it subsequently passes through the stiff fluid era, q=2$q=2$, w=1$w=1$, the radiation dominated era, q=1$q=1$, w=1/3$w=1/3$ and the matter dominated era, q=1/2$q=1/2$, w=0$w=0$. Finally, deceleration halts, q=0$q=0$, w=−1/3$w=-1/3$, and it then encounters a transition to the accelerating phase. Asymptotically the Universe reaches yet another inflationary phase q→−1$q\to -1$, w→−1$w\to -1$. Such evolution is independent of the form of the potential and the sign of the kinetic energy term, i.e., even a non-canonical kinetic energy is unable to phantomize (w<−1)$(w<-1)$ the model.     

Electronic and magnetic properties of hydrogenated graphene nanoflakes

We investigated the energetic stability, electronic, and magnetic properties of hydrogenated graphene nanoflakes (GNFs) by using density-functional theory (DFT). Hydrogenated GNFs were found to be the stable heterojunction structures. As the increase of H coverage, a transition of a small-gap semiconductor to wide-gap semiconductor occurs, accompanied with a nonmagnetic (with the coverage χ=0$\chi =0$) → magnetic (with the coverage 0<χ<1$0<\chi <1$) → nonmagnetic (with the coverage χ=1$\chi =1$) transfer for hexagonal nanoflakes and magnetic (with the coverage 0?χ<1$0?\chi <1$) → nonmagnetic (with the coverage χ=1$\chi =1$) transfer for triangular nanoflakes. The efficacious tune of band gaps and the magnetic moments on these nanoflakes by hydrogenation offers an effectual avenue for the applications of C-based nanomagnets.     

Magnetic properties of smooth terminating dipole bands in Te

Three strongly coupled sequences have been established in ^110,112Te up to high spins. They are interpreted in terms of deformed structures built on proton 1-particle–1-hole excitations that reach termination at I∼40?$I\sim 40?$. This is the first observation of smooth terminating dipole structures in this mass region. Lifetime measurements have allowed the extraction of experimental B(M1;I→I−1)$B(\mathrm{M}1;I\to I-1)$ and B(E2;I→I−2)$B(\mathrm{E}2;I\to I-2)$ reduced transition rates for one of the dipole bands in ¹¹⁰Te. The results support the deformed interpretation.     

The constraint on FCNC coupling of the top quark with a gluon from ep-collisions

Using the constraint on the single top production cross-section obtained at the HERA collider, σ(ep→etX)$\sigma (ep\to etX)$, we evaluate an upper limit on coupling constant of the anomalous top quark interaction with a gluon via flavor-changing neutral current: |κ_tgq/Λ|?0.4 TeV⁻¹$|{\kappa }_{tgq}/\Lambda |?0.4{\text{TeV}}^{\mathrm{-1}}$, BR(t→gq)<13%$\mathrm{BR}(t\to gq)<13\mathrm{\%}$.     

Suppression of flavor symmetry breaking in B decay sum rules

While flavor symmetries are useful for studying hadronic B   decays, symmetry relations for amplitudes and decay rates are usually violated by first order symmetry breaking corrections. We point out two cases in which first order symmetry breaking is suppressed by a small ratio of amplitudes: (1) An isospin sum rule for four B→Kπ$B\to K\pi$ decays, where isospin breaking is shown to be negligible. (2) An SU(3)$\mathrm{SU}(3)$ sum rule for pairs of B→Kπ$B\to K\pi$ and B→Kη₈$B\to K{\eta }_8$, generalized to pairs of B→Kπ$B\to K\pi$, B→Kη$B\to K\eta$ and B→Kη^′$B\to K{\eta }^{\prime }$.     

First observation of electronic structure of the even parity boron acceptor states in diamond

We use electronic Raman scattering for studying the band structure of the ns$\mathrm{n}s$ boron acceptor states in diamond. For the first time, the spin–orbit splitting of these acceptor states and the 1s→ns$1s\to \mathrm{n}s$ Lyman series of transitions are observed. The spin–orbit splitting linearly increases with n number. Lyman series exhibit fine structure consisting of four bands each. The energy spacing between series is equal to ∼13 meV$\sim 13\text{meV}$. Evolution of Raman spectra of the boron-doped diamond with increasing boron concentration is shown. Mott transition is revealed in Raman spectrum. Correct values of Luttinger parameters for diamond are specified.     

FCNC-induced heavy-quark events at the LHC from supersymmetry

We analyze the production and subsequent decay of the neutral Higgs bosons h≡h⁰,H⁰,A⁰$h\equiv h^0,H^0,A^0$ of the MSSM into electrically neutral quark pairs of different flavors (qq^′≡tc,bs$q{q}^{\prime }\equiv tc,bs$, depending on h  ) at the LHC, i.e. σ(pp→h→qq^′)$\sigma (pp\to h\to q{q}^{\prime })$, and compare with the direct FCNC production mechanisms σ(pp→qq^′)$\sigma (pp\to q{q}^{\prime })$. The cross-sections are computed in the unconstrained MSSM with minimal flavor-mixing sources and taking into account the stringent bounds from b→sγ$b\to s\gamma$. We extend the results previously found for these FCNC processes, which are singularly uncommon in the SM. Specifically, we report here on the SUSY-EW part of σ(pp→h→qq^′)$\sigma (pp\to h\to q{q}^{\prime })$ and the SUSY-QCD and SUSY-EW contributions to σ(pp→bs)$\sigma (pp\to bs)$. In this way, the complete map of MSSM predictions for the qq^′$q{q}^{\prime }$-pairs produced at the LHC becomes available. The upshot is that the most favorable channels are: (1) the Higgs boson FCNC decays into bs, and (2) the direct production of tc   pairs, both of them at the ∼1 pb$\sim 1\text{pb}$ level and mediated by SUSY-QCD effects. If, however, the SUSY-QCD part is suppressed, we find a small SUSY-EW yield for σmax_{(pp→h→tc)}∼¹⁰⁻⁴ pb$\sigma {(pp\to h\to tc)}_{\max }\sim {10}^{\mathrm{-4}}\text{pb}$ but, at the same time, σmax_{(pp→h→bs)}∼0.1–1 pb$\sigma {(pp\to h\to bs)}_{\max }\sim 0.1\text{–}1\text{pb}$, which implies a significant number (∼¹⁰⁴–¹⁰⁵$\sim {10}^4\text{–}{10}^5$) of bs   pairs per 100 fb⁻¹$100{\text{fb}}^{\mathrm{-1}}$ of integrated luminosity.     

Detecting Higgs bosons with muons at hadron colliders

We investigate the prospects for the discovery of neutral Higgs bosons with a pair of muons by direct searches at the CERN large hadron collider (LHC) as well as by indirect searches in the rare decay Bs→μ⁺μ⁻$B_s\to {\mu }^{+}{\mu }^{-}$ at the Fermilab Tevatron and the LHC. Promising results are found for the minimal supersymmetric standard model, the minimal supergravity (mSUGRA) model, and supergravity models with non-universal Higgs masses (NUHM SUGRA). For tanβ?50$\tan \beta ?50$, we find that (i) the contours for a branching fraction of B(Bs→μ⁺μ⁻)=1×¹⁰⁻⁸$B(B_s\to {\mu }^{+}{\mu }^{-})=1\times {10}^{\mathrm{-8}}$ in the parameter space are very close to the 5σ   contours for pp→b?⁰→bμ⁺μ⁻+X$pp\to b{?}^0\to b{\mu }^{+}{\mu }^{-}+X$, ?⁰=h⁰${?}^0=h^0$, H⁰$H^0$, A⁰$A^0$ at the LHC with an integrated luminosity (L) of 30 fb⁻¹, (ii) the regions covered by B(Bs→μ⁺μ⁻)?5×¹⁰⁻⁹$B(B_s\to {\mu }^{+}{\mu }^{-})?5\times {10}^{\mathrm{-9}}$ and the discovery region for b?⁰→bμ⁺μ⁻$b{?}^0\to b{\mu }^{+}{\mu }^{-}$ with 300 fb⁻¹ are complementary in the mSUGRA parameter space, (iii) in NUHM SUGRA models, a discovery of B(Bs→μ⁺μ⁻)?5×¹⁰⁻⁹$B(B_s\to {\mu }^{+}{\mu }^{-})?5\times {10}^{\mathrm{-9}}$ at the LHC will cover regions of the parameter space beyond the direct search for b?⁰→bμ⁺μ⁻$b{?}^0\to b{\mu }^{+}{\mu }^{-}$ with L=300 fb⁻¹$L=300{\text{fb}}^{\mathrm{-1}}$.     

Analytical solutions to time-fractional partial differential equations in a two-dimensional multilayer annulus

In this paper, analytical solutions to time-fractional partial differential equations in a multi-layer annulus are presented. The final solutions are obtained in terms of Mittag-Leffler function by using the finite integral transform technique and Laplace transform technique. In addition, the classical diffusion equation (α=1$\alpha =1$), the Helmholtz equation (α→0$\alpha \to 0$) and the wave equation (α=2$\alpha =2$) are discussed as special cases. Finally, an illustrative example problem for the three-layer semi-circular annular region is solved and numerical results are presented graphically for various kind of order of fractional derivative.     

Properties of CFTs dual to charged BTZ black hole

We study properties of strongly coupled CFT's with non-zero background electric charge in 1+1$1+1$ dimensions by studying the dual gravity theory—which is a charged BTZ black hole. Correlators of operators dual to scalars, gauge fields and fermions are studied at both T=0$T=0$ and T≠0$T\ne 0$. In the T=0$T=0$ case we are also able to compare with analytical results based on AdS₂${\mathit{AdS}}_2$ and find reasonable agreement. In particular the correlation between log periodicity and the presence of finite spectral density of gapless modes is seen. The real part of the conductivity (given by the current–current correlator) also vanishes as ω→0$\omega \to 0$ as expected. The fermion Green's function shows quasiparticle peaks with approximately linear dispersion but the detailed structure is neither Fermi liquid nor Luttinger liquid and bears some similarity to a “Fermi–Luttinger” liquid. This is expected since there is a background charge and the theory is not Lorentz or scale invariant. A boundary action that produces the observed non-Luttinger liquid like behavior (k  -independent non-analyticity at ω=0$\omega =0$) in the Green's function is discussed.     

The apparent excess in the Higgs to di-photon rate at the LHC: New Physics or QCD uncertainties?

The Higgs boson with a mass _MH≈126 GeV$M_H\approx 126\text{GeV}$ has been observed by the ATLAS and CMS experiments at the LHC and a total significance of about five standard deviations has been reported by both collaborations when the channels H→γγ$H\to \gamma \gamma$ and H→ZZ→4?$H\to ZZ\to 4?$ are combined. Nevertheless, while the rates in the later search channel appear to be in accord with those predicted in the Standard Model, there seems to be an excess of data in the case of the H→γγ$H\to \gamma \gamma$ discovery channel. Before invoking new physics contributions to explain this excess in the di-photon Higgs rate, one should verify that standard QCD effects cannot account for it. We describe how the theoretical uncertainties in the Higgs boson cross section for the main production process at the LHC, gg→H$gg\to H$, which are known to be large, should be incorporated in practice. We further show that the discrepancy between the theoretical prediction and the measured value of the gg→H→γγ$gg\to H\to \gamma \gamma$ rate, reduces to about one standard deviation when the QCD uncertainties are taken into account.