arXiv subjects

Priyanka

Publications and source records attributed to Priyanka.

25 records · Page 2Linked to original sources

arXiv2019

First measurement of tW production cross-section at $\sqrt s$~= 13 TeV with CMS

The inclusive cross-section for tW production in proton-proton collisions at $\sqrt{s} = 13$ TeV is measured for an integrated luminosity of 35.9 fb$^{-1}$ collected by the CMS experiment. The measurement is performed using events with one electron and one muon in the final state and at least one b-quark jet, and utilises kinematic differences between the signal and the dominating $t\bar{t}$ background using multivariant discriminants which is designed to disentangle the two processes. The measured cross-section of $σ= 63.1 \pm 1.8~({\rm stat}) \pm 6.4~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is observed to be in agreement with the Standard Model.

hep-ex↗

arXiv2018

Anomalous heat equation in a system connected to thermal reservoirs

We study anomalous transport in a one-dimensional system with two conserved quantities in presence of thermal baths. In this system we derive exact expressions of the temperature profile and the two point correlations in steady state as well as in the non-stationary state where the later describes the relaxation to the steady state. In contrast to the Fourier heat equation in the diffusive case, here we show that the evolution of the temperature profile is governed by a non-local anomalous heat equation. We provide numerical verifications of our results.

cond-mat.stat-mech↗

arXiv2017

Structural and Magnetic Characterizations of Co2FeGa/SiO2 Nanoparticles Prepared via Chemical Route

We report the synthesis of Co2FeGa/SiO2 nanoparticles by sol-gel method and characterization using x-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetic measurements. The Rietveld refinements of XRD data with space group Fm-3m clearly show the formation of A2 disorder single phase and the lattice constant is found to be 5.738 Å. The energy-dispersive x-ray spectroscopy (EDX) confirm the elemental composition close the desired values. The value of coercivity is found to be around 283 Oe and 126 Oe, measured at 10 K and 300 K, respectively. We observed the saturation magnetization significantly lower than expected from Slater-Pauling rule. This decrease in the magnetic moment might be due to the presence of amorphous SiO2 during the synthesis process. A large content of small size SiO2 particles along with Co2FeGa nanoparticles are also found in TEM study.

cond-mat.mes-hall↗

arXiv2017

Tuning ferromagnetism and spin state in La$_{(1-x)}$$A_x$CoO$_3$ ($A=$ Sr, Ca) nanoparticles

We use the x-ray diffraction, magnetic susceptibility, isothermal magnetization, and photoelectron spectroscopy to study the structural, magnetic and electronic properties of La$_{(1-x)}$$A_x$CoO$_3$ ($A=$ Sr, Ca; $x=$ 0 -- 0.2) nanoparticles. The Rietveld refinements of room temperature powder x-ray diffraction data confirm the single phase and the rhombohedral crystal structure with R$\bar{3}$C space group. We find drastic changes in the magnetic properties and spin-states with Sr/Ca substitution (hole doping). For $x=$ 0 sample, the magnetic measurements show a ferromagnetic transition at T$_{\rm C}$$\approx$85 K, which shifted significantly to higher temperatures with hole doping; simultaneously a significant increase in the spontaneous magnetic moment has been observed. Whereas, the coercive field H$_{\rm C}$ values are 7, 4.4 and 13.2~kOe for $x=$ 0, 0.2 (Sr), and 0.2(Ca) samples. Furthermore, the FC magnetization shows a ferromagnetic Brillouin function like behavior at low temperatures for Ca samples. We demonstrate that the Sr/Ca substitution increases the population of IS (Co$^{3+}$) and LS (Co$^{4+}$) states and tune the ferromagnetism in nanoparticles via double-exchange interactions between Co$^{3+}$-- Co$^{4+}$. Our results suggest an important role of hole carriers and nano-size effect in controlling the spin-state and magnetism in La$_{(1-x)}$$A_x$CoO$_3$ nanoparticles.

cond-mat.mes-hall↗

arXiv2016

Critical dynamics of classical systems under slow quench

We study the slow quench dynamics of a one-dimensional nonequilibrium lattice gas model which exhibits a phase transition in the stationary state between a fluid phase with homogeneously distributed particles and a jammed phase with a macroscopic hole cluster. Our main result is that in the critical region ({\it i.e.}, at the critical point and in its vicinity) where the dynamics are assumed to be frozen in the standard Kibble-Zurek argument, the defect density exhibits an algebraic decay in the inverse annealing rate with an exponent that can be understood using critical coarsening dynamics. However, in a part of the critical region in the fluid phase, the standard Kibble-Zurek scaling holds. We also find that when the slow quench occurs deep into the jammed phase, the defect density behavior is explained by the rapid quench dynamics in this phase.

cond-mat.stat-mech↗

arXiv2016

Critical dynamics of the jamming transition in one-dimensional nonequilibrium lattice-gas models

We consider several one-dimensional driven lattice gas models that show a phase transition in the stationary state between a high-density fluid phase in which the particles are homogeneously distributed and a low-density jammed phase where a hole cluster of macroscopic length forms in front of a particle. Using a hydrodynamic equation for an interface growth model obtained from the driven lattice gas models of interest here, we find that in the fluid phase, the roughness exponent and the dynamic exponent that, respectively, characterise the scaling of the saturation width and the relaxation time of the interface with the system size are given by the KPZ exponents. However, at the critical point, we show analytically that when the equal time density-density correlation function decays slower than inverse distance, the roughness exponent varies continuously with a parameter in the hop rates but it is one half otherwise. Using these results and numerical simulations for the density-density autocorrelation function, we further find that the dynamic exponent $z=3/2$ in all the cases.

cond-mat.stat-mech↗

arXiv2014

Two-point correlation function of an exclusion process with hole-dependent rates

We consider an exclusion process on a ring in which a particle hops to an empty neighbouring site with a rate that depends on the number of vacancies $n$ in front of it. In the steady state, using the well known mapping of this model to the zero range process, we write down an exact formula for the partition function and the particle-particle correlation function in the canonical ensemble. In the thermodynamic limit, we find a simple analytical expression for the generating function of the correlation function. This result is applied to the hop rate $u(n)=1+(b/n)$ for which a phase transition between high-density laminar phase and low-density jammed phase occurs for $b > 2$. For these rates, we find that at the critical density, the correlation function decays algebraically with a continuously varying exponent $b-2$. We also calculate the two-point correlation function above the critical density, and find that the correlation length diverges with a critical exponent $ν=1/(b-2)$ for $b < 3$ and $1$ for $b > 3$. These results are compared with those obtained using an exact series expansion for finite systems.

cond-mat.stat-mech↗