Hadronic final state predictions from CCFM: the hadron-level Monte Carlo generator CASCADE

We discuss a practical formulation of backward evolution for the CCFM small-$x$ evolution equation and show results from its implementation in the new Monte Carlo event-generator CASCADE.Comment: 20 pages, 8 figure

Dynamical Exchanges in Facilitated Models of Supercooled liquids

We investigate statistics of dynamical exchange events in coarse--grained models of supercooled liquids in spatial dimensions $d=1$, 2, and 3. The models, based upon the concept of dynamical facilitation, capture generic features of statistics of exchange times and persistence times. Here, distributions for both times are related, and calculated for cases of strong and fragile glass formers over a range of temperatures. Exchange time distributions are shown to be particularly sensitive to the model parameters and dimensions, and exhibit more structured and richer behavior than persistence time distributions. Mean exchange times are shown to be Arrhenius, regardless of models and spatial dimensions. Specifically, $\sim c^{-2}$, with $c$ being the excitation concentration. Different dynamical exchange processes are identified and characterized from the underlying trajectories. We discuss experimental possibilities to test some of our theoretical findings.Comment: 11 pages, 14 figures, minor corrections made, paper published in Journal of Chemical Physic

Ferromagnetic Domain Structure of La0.78Ca0.22MnO3 Single Crystals

The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La0.78Ca0.22MnO3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the investigated crystals. With decreasing temperature the regular network of ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range of 70-150 K. The apparent rotation of the domain walls can be understood in terms of the Jahn-Teller deformation of the orthorhombic unit cell, accompanied by additional twinning.Comment: 7 pages, 5 figures, to be published in PR

Double Entropic Stochastic Resonance

We demonstrate the appearance of a purely entropic stochastic resonance (ESR) occurring in a geometrically confined system, where the irregular boundaries cause entropic barriers. The interplay between a periodic input signal, a constant bias and intrinsic thermal noise leads to a resonant ESR-phenomenon in which feeble signals become amplified. This new phenomenon is characterized by the presence of two peaks in the spectral amplification at corresponding optimal values of the noise strength. The main peak is associated with the manifest stochastic resonance synchronization mechanism involving the inter-well noise-activated dynamics while a second peak relates to a regime of optimal sensitivity for intra-well dynamics. The nature of ESR, occurring when the origin of the barrier is entropic rather than energetic, offers new perspectives for novel investigations and potential applications. ESR by itself presents yet another case where one constructively can harvest noise in driven nonequilibrium systems.Comment: 6 pages, 7 figures ; Europhys. Lett., in press (2009

Ab initio formulation of the four-point conductance of interacting electronic systems

We derive an expression for the four-point conductance of a general quantum junction in terms of the density response function. Our formulation allows us to show that the four-point conductance of an interacting electronic system possessing either a geometrical constriction and/or an opaque barrier becomes identical to the macroscopically measurable two-point conductance. Within time-dependent density-functional theory the formulation leads to a direct identification of the functional form of the exchange-correlation kernel that is important for the conductance. We demonstrate the practical implementation of our formula for a metal-vacuum-metal interface

Unintegrated gluon distribution and soft pp collisions at LHC

We found the parameterization of the unintegrated gluon distribution from the best description of the LHC data on the inclusive spectra of hadrons produced in $pp$ collisions at the mid-rapidity region and small transverse momenta. It is different from the one obtained within perturbative QCD only at low intrinsic transverse momenta $k_t$. The application of this distribution to analysis of the $e-p$ DIS allows us to get the results which do not contradict the H1 and ZEUS data on the structure functions at low $x$. So, the connection between the soft processes at LHC and low-$x$ physics at HERA is found.Comment: 8 pages, 4 figures. Contributed to 3rd Workshop on Multi-Parton Interactions at the LHC (MPI11), Hamburg, 21-25 November 201

Top quark forward-backward asymmetry and charge asymmetry in left-right twin Higgs model

In order to explain the Tevatron anomaly of the top quark forward-backward asymmetry $A_{FB}^t$ in the left-right twin Higgs model, we choose to give up the lightest neutral particle of $\hat{h}$ field as a stable dark matter candidate. Then a new Yukawa interaction for $\hat{h}$ is allowed, which can be free from the constraint of same-sign top pair production and contribute sizably to $A_{FB}^t$. Considering the constraints from the production rates of the top pair ($t\bar t$), the top decay rates and $t\bar{t}$ invariant mass distribution, we find that this model with such new Yukawa interaction can explain $A_{FB}^t$ measured at the Tevatron while satisfying the charge asymmetry $A_{C}^t$ measured at the LHC.Moreover, this model predicts a strongly correlation between $A_{C}^t$ at the LHC and $A_{FB}^t$ at the Tevatron, i.e., $A_{C}^t$ increases as $A_{FB}^t$ increases.Comment: 17 pages, 9 figures; matches the published versio

11B^{11}B NMR and Relaxation in MgB2MgB_2 Superconductor

$^{11}B$ NMR and nuclear spin-lattice relaxation rate (NSLR) are reported at 7.2 Tesla and 1.4 Tesla in powder samples of the intermetallic compound $MgB_2$ with superconducting transition temperature in zero field $T_c$ = 39.2 K. From the first order quadrupole perturbed NMR specrum a quadrupole coupling frequency of 835 $\pm$ 5 kHz is obtained. The Knight shift is very small and it decreases to zero in the superconducting phase. The NSLR follows a linear law with $T_1T$ = 165 $\pm$ 10 (sec K) . The results in the normal phase indicate a negligible $s$-character of the wave function of the conduction electrons at the Fermi level. Below $T_c$ the NSLR is strongly field dependent indicating the presence of an important contribution related to the density and the thermal motion of flux lines. No coherence peak is observed at the lower field investigated (1.4 T)

INFLUENCE OF LIGNIN ON DIGESTIBILITY OF FORAGE CELL WALL MATERIAL

One-hundred-ninety-four grass samples, representing eight species, were used to determine the relationships of in vitro forage dry matter, cell wall, hemicellulose and cellulose digestibilities with lignin concentration. Linear regressions indicated that dry matter digestion was inhibited to a lesser degree (P\u3c.05) by lignin concentration than was cell wall digestion. Results for linear regressions of hemicellulose and cellulose digestibilities as functions of lignin concentration showed a greater (P\u3c.05) effect of lignin on cellulose digestion. Smooth bromegrass and switchgrass were collected at both Clay Center and Mead, NE; for all digestibility measures, the Clay Center samples gave stronger (P\u3c.05) negative correlations with lignin. A comparison of linear and curvilinear models indicated that, for all digestion measurements, the curvilinear model was a better (P\u3c.05) description of relationships with lignin concentration. For all digestibility measures, lignin\u27s inhibiting effect declined at higher lignin concentrations. The curvilinear models did not show significant differences among the digestibility measures for effect of lignin. The demonstration that the forage digestibility response to lignin\u27s inhibitory effect is curvilinear in nature suggests that the mechanism of hgnin\u27s inhibition is complex

Modular termination verification for non-blocking concurrency

© Springer-Verlag Berlin Heidelberg 2016.We present Total-TaDA, a program logic for verifying the total correctness of concurrent programs: that such programs both terminate and produce the correct result. With Total-TaDA, we can specify constraints on a thread’s concurrent environment that are necessary to guarantee termination. This allows us to verify total correctness for nonblocking algorithms, e.g. a counter and a stack. Our specifications can express lock- and wait-freedom. More generally, they can express that one operation cannot impede the progress of another, a new non-blocking property we call non-impedance. Moreover, our approach is modular. We can verify the operations of a module independently, and build up modules on top of each other