6,608 research outputs found
Effect of simultaneous application of field and pressure on magnetic transitions in LaCaMnO
We study combined effect of hydrostatic pressure and magnetic field on the
magnetization of LaCaMnO. We do not observe any
significant effect of pressure on the paramagnetic to ferromagnetic transition.
However, pressure asymmetrically affects the thermal hysteresis across the
ferro-antiferromagnetic first-order transition, which has strong field
dependence. Though the supercooling (T*) and superheating (T**) temperatures
decrease and the value of magnetization at 5K (M) increases with
pressure, T* and M shows abrupt changes in tiny pressure of 0.68kbar.
These anomalies enhance with field. In 7Tesla field, transition to
antiferromagnetic phase disappears in 0.68kbar and M show significant
increase. Thereafter, increase in pressure up to 10kbar has no noticeable
effect on the magnetization
Evidence of 1D behaviour of He confined within carbon-nanotube bundles
We present the first low-temperature thermodynamic investigation of the
controlled physisorption of He gas in carbon single-wall nanotube (SWNT)
samples. The vibrational specific heat measured between 100 mK and 6 K
demonstrates an extreme sensitivity to outgassing conditions. For bundles with
a few number of NTs the extra contribution to the specific heat, C,
originating from adsorbed He at very low density displays 1D behavior,
typical for He atoms localized within linear channels as grooves and
interstitials, for the first time evidenced. For larger bundles, C
recovers the 2D behaviour akin to the case of He films on planar
substrates (grafoil).Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
The nonleptonic decays of -flavored mesons to -wave charmonium and charm meson states
The detection of radially excited heavy meson \\states in recent years and
measurement of heavy meson decays, particularly and
, by the LHCb and ATLAS Collaborations, have aroused
a lot of theoretical interest in the nonleptonic decays of -flavored mesons.
In this paper, we study the exclusive two-body nonleptonic ,
, and -meson decays to two vector meson
() states. Assuming the factorization hypothesis, we calculate the
weak-decay form factors from the overlapping integrals of meson wave functions,
in the framework of the relativistic independent quark (RIQ) model. We find a
few dominant decay modes: , ,
, and with predicted branching fractions of 1.54, 1.42, 1.17, 0.53 and 0.52
(in ), which are experimentally accessible. The predicted branching
fractions for corresponding decay modes to excited () states, obtained in
the order lie within the detection accuracy of the
current experiments at LHCb and Tevatron. The sizeable -odd fractions
predicted for -meson decay to two charmful states:
and indicate significant -violation hinting at
the so-called new physics beyond the standard model.Comment: arXiv admin note: text overlap with arXiv:2202.0116
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