Vector boson parameters: Scheme dependence and theoretical uncertainties

The renormalization scheme dependence of electroweak parameters shifts is used to estimate uncertainties due to higher order effects. Parameter shifts are calculated from weakly scheme dependent quantities, taking care of a systematic leading log summation. A “non-standard” definition of sin² θ _W is also considered which is to be used if the ρ-parameter is kept as free parameter. Results for the leptonic decay widths of the vector bosons are also given.     

The asymmetry of solar-neutrino fluxes

With effective heliolatitude L _eff(n) for each solar-neutrino run n we separate all available Homestake experimental data for more than two solar cycles (1970–1994) on three zones SOUTH, EQUATORIAL, and NORTH in dependence on the heliolatitude (where detected neutrinos cross the Sun’s surface). For each latitudinal zone, we determine the average solar electron neutrino flux and correlations with effective solar-activity parameters for asymmetrical latitudinal belts. The obtained results indicate that neutrino should have nonzero mass and nonzero magnetic moment.     

Global analysis of helicity parton densities and their uncertainties

We present a new analysis of the helicity parton distributions of the nucleon. The analysis takes into account the available data from inclusive and semi-inclusive polarized deep inelastic scattering, as well as from polarized proton-proton (p-p) scattering at RHIC. For the first time, all theoretical calculations are performed fully at next-to-leading order (NLO) of perturbative QCD, using a method that allows incorporation of the NLO corrections in a very fast and efficient way in the analysis. We find evidence for a rather small gluon polarization in the nucleon, over a limited region of momentum fraction, and for interesting flavor patterns in the polarized sea.     

High cumulants of conserved charges and their statistical uncertainties

We study the influence of measured high cumulants of conserved charges on their associated statistical uncertainties in relativistic heavy-ion collisions. With a given number of events, the measured cumulants randomly fluctuate with an approximately normal distribution, while the estimated statistical uncertainties are found to be correlated with corresponding values of the obtained cumulants. Generally, with a given number of events, the larger the cumulants we measure, the larger the statistical uncertainties that are estimated. The error-weighted averaged cumulants are dependent on statistics. Despite this effect, however, it is found that the three sigma rule of thumb is still applicable when the statistics are above one million.     

Tweed microstructures: Experimental observations and some theoretical models

Experimental observations, mainly by transmission electron microscopy, of tweed microstructures in minerals (K-feldspar and cordierite), high-T _c superconductors (Co-doped YBCO) and metals are reviewed. Structural models of the local structure within the tweed are compared and evaluated with respect to spectroscopic measurements in a number of systems. It is concluded that in tweed microstructures which result from symmetry changes driven by cation-ordering, the local degree of order is not itself modulated. A model based on twin-related domains of the low symmetry form is consistent with experimental observations. Mechanisms of coarsening of the tweed microstructure to form the lamellar twinning observed in the fully ordered structure are briefly reviewed.     

Monojet signatures from heavy colored particles: future collider sensitivities and theoretical uncertainties

In models with colored particle \(\mathcal {Q}\) that can decay into a dark matter candidate X, the relevant collider process \(pp\rightarrow \mathcal {Q}\bar{\mathcal {Q}}\rightarrow X\bar{X}\,+\,\)jets gives rise to events with significant transverse momentum imbalance. When the masses of \(\mathcal {Q}\) and X are very close, the relevant signature becomes monojet-like, and Large Hadron Collider (LHC) search limits become much less constraining. In this paper, we study the current and anticipated experimental sensitivity to such particles at the High-Luminosity LHC at \(\sqrt{s}=14\) TeV with \(\mathcal {L}=3\) ab\(^{-1}\) of data and the proposed High-Energy LHC at \(\sqrt{s}=27\) TeV with \(\mathcal {L}=15\) ab\(^{-1}\) of data. We estimate the reach for various Lorentz and QCD color representations of \(\mathcal {Q}\). Identifying the nature of \(\mathcal {Q}\) is very important to understanding the physics behind the monojet signature. Therefore, we also study the dependence of the observables built from the \(pp\rightarrow \mathcal {Q}\bar{\mathcal {Q}} + j \) process on \(\mathcal {Q}\) itself. Using the state-of-the-art Monte Carlo suites MadGraph5_aMC@NLO+Pythia8 and Sherpa, we find that when these observables are calculated at NLO in QCD with parton shower matching and multijet merging, the residual theoretical uncertainties are comparable to differences observed when varying the quantum numbers of \(\mathcal {Q}\) itself. We find, however, that the precision achievable with NNLO calculations, where available, can resolve this dilemma.     

Experimental and theoretical observations on DDT in smooth narrow channels

A combined experimental and theoretical study of deflagration-to-detonation transition (DDT) in smooth narrow channels is presented. Some of the distinguishing features characterizing the late stages of DDT are shown to be qualitatively captured by a simple one-dimensional scalar equation. Inspection of the structure and stability of the traveling wave solutions found in the model, and comparison with experimental observations, suggest a possible mechanism responsible for front acceleration and transition to detonation.     

Dynamic response of structures with statistical uncertainties in their stiffnesses

A technique is derived to compute the instantaneous transient response statistics of an undamped linear N-degree-of-freedom structure subjected to arbitrary but deterministic forcing functions, when random uncertainties are introduced into the stiffness matrix. The uncertainties are modeled as perturbations with a Gaussian distribution. For the case of an impulsive driving function, simple bounds are derived showing the growth with time of the response uncertainty as a function of the model uncertainty.