Effect of simultaneous application of field and pressure on magnetic transitions in La0.5{_{0.5}}Ca0.5{_{0.5}}MnO3{_{3}}

We study combined effect of hydrostatic pressure and magnetic field on the magnetization of La${_{0.5}}$Ca${_{0.5}}$MnO${_{3}}$. 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$_{5K}$) increases with pressure, T* and M$_{5K}$ 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$_{5K}$ show significant increase. Thereafter, increase in pressure up to $\sim$10kbar has no noticeable effect on the magnetization

Evidence of 1D behaviour of He4^4 confined within carbon-nanotube bundles

We present the first low-temperature thermodynamic investigation of the controlled physisorption of He$^{4}$ 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$_{ads}$, originating from adsorbed He$^{4}$ 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$_{ads}$ recovers the 2D behaviour akin to the case of He$^{4}$ films on planar substrates (grafoil).Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

The nonleptonic decays of bb-flavored mesons to SS-wave charmonium and charm meson states

The detection of radially excited heavy meson \\states in recent years and measurement of heavy meson decays, particularly $B_c^+\to J/\psi D_s^+$ and $B_c^+\to J/\psi D_s^{*+}$, by the LHCb and ATLAS Collaborations, have aroused a lot of theoretical interest in the nonleptonic decays of $b$-flavored mesons. In this paper, we study the exclusive two-body nonleptonic $\bar{B}^0$, $\bar{B_s^0}$, $B^-$ and $B_c^-$-meson decays to two vector meson ($V_1(nS)V_2$) 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: $B^-\to D^{*0}\rho^-$, $\bar{B^0}\to D^{*+}\rho^-$, $\bar{B_s^0}\to D_s^{*+}\rho^-$, $B^-\to J/\psi K^{*-}$ and $B_c^-\to J/\psi D_s^{*-}$ 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 ($2S$) states, obtained in the order ${\cal O }(10^{-3}-10^{-4})$ lie within the detection accuracy of the current experiments at LHCb and Tevatron. The sizeable $CP$-odd fractions predicted for $B_c^-$-meson decay to two charmful states: $D^{*0}D^{*-}_{(s)}$ and $\bar{D}^{*0}D^{*-}_{(s)}$ indicate significant $CP$-violation hinting at the so-called new physics beyond the standard model.Comment: arXiv admin note: text overlap with arXiv:2202.0116