294 research outputs found
Quantifying jet transport properties via large hadron production
Nuclear modification factor for large single hadron is studied
in a next-to-leading order (NLO) perturbative QCD (pQCD) parton model with
medium-modified fragmentation functions (mFFs) due to jet quenching in
high-energy heavy-ion collisions. The energy loss of the hard partons in the
QGP is incorporated in the mFFs which utilize two most important parameters to
characterize the transport properties of the hard parton jets: the jet
transport parameter and the mean free path , both at
the initial time . A phenomenological study of the experimental data
for is performed to constrain the two parameters with
simultaneous fits to RHIC as well as LHC data. We obtain
for energetic quarks GeV/fm and
fm in central collisions at
GeV, while GeV/fm, and
fm in central collisions at
TeV. Numerical analysis shows that the best fit favors a
multiple scattering picture for the energetic jets propagating through the bulk
medium, with a moderate averaged number of gluon emissions. Based on the best
constraints for and , the estimated value for the
mean-squared transverse momentum broadening is moderate which implies that the
hard jets go through the medium with small reflection.Comment: 8 pages, 6 figures, revised versio
Emerging chiral edge states from the confinement of a magnetic Weyl semimetal in CoSnS
The quantum anomalous Hall effect (QAHE) and magnetic Weyl semimetals (WSMs)
are topological states induced by intrinsic magnetic moments and spin-orbit
coupling. Their similarity suggests the possibility of achieving the QAHE by
dimensional confinement of a magnetic WSM along one direction. In this study,
we investigate the emergence of the QAHE in the two-dimensional (2D) limit of
magnetic WSMs due to finite size effects in thin films and step-edges. We
demonstrate the feasibility of this approach with effective models and real
materials. To this end, we have chosen the layered magnetic WSM
CoSnS, which features a large anomalous Hall conductivity and
anomalous Hall angle in its 3D bulk, as our material candidate. In the 2D limit
of CoSnS two QAHE states exist depending on the stoichiometry of
the 2D layer. One is a semimetal with a Chern number of 6, and the other is an
insulator with a Chern number of 3. The latter has a band gap of 0.05 eV, which
is much larger than that in magnetically doped topological insulators. Our
findings naturally explain the existence of chiral states in step edges of bulk
CoSnS which habe been reported in a recent experiment at
and present a realistic avenue to realize QAH states in thin films of magnetic
WSMs.Comment: Revised 3rd version of the manuscrip
Magnetostructural Transformation and Magnetoresponsive Properties of MnNiGe1-xSnx Alloys
The martensitic and magnetic phase transformations in MnNiGe1-xSnx (0 \leq x
\leq 0.200) alloys were investigated using X-ray diffraction (XRD),
differential thermal analysis (DTA) and magnetization measurements. Results
indicate that the increasing Sn substitution in MnNiGe1-xSnx results in (i)
decrease of martensitic transformation temperature from 460 to 100 K and (ii)
conversion of AFM spiral to antiparallel AFM strcuture in martensite. Based on
these, the remarkable magnetic-field-induced PM/spiral-AFM and FM/AFM
magnetostructural transformations and, large positive and negative
magnetocaloric effects are obtained. The magnetoresponsive effects of
MnNiGe1-xSnx alloys are enhanced by Sn substitution. A structural and magnetic
phase diagram of MnNiGe1-xSnx alloys has been proposed.Comment: 3 pages and 4 figure
"Hang" and "Crash" in Fault Analysis of Philips HD Series Color Doppler Ultrasound in Summary of Medical Equipment Maintenance Experience
Color doppler ultrasound is an important imaging equipment to examine systemic diseases in hospital.Over the past years, the Philips HD series ultrasound system have attracted great attention for their outstanding imaging ability. This paper introduce the structure principle of HD series ultrasound system,and introduces the difference and different troubleshooting methods when HD color doppler ultrasound system displays' Hang 'and' Crash 'faults
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